Psychology in early childhood

The journal writing is based on the readings of the chapter every week (chapter 3 and 4 book is attached  ). You can pick a topic you like and expand your thoughts based on question asked in the journal. On your papers include the typed questions before your response.  Answers must be typed and double-spaced with 1” margins on all four sides and 12 pt font. Make sure to use in text citation.  Answer all the questions below. 

1. Identify one important concept, research finding, theory, or idea in the current module and briefly describe it.
2. Describe why you think this is an important concept.
3. What possible research could be added to your concept?
4. Describe how this relates to your life.

develop
How Children
Robert Siegler Judy DeLoache Nancy Eisenberg Jenny Saffran
F o u r t h E d i t i o n
This is an exciting time in the field of child development. The past decade has brought new theories, new ways
of thinking, new areas of research, and innumerable new findings to the field. We originally wrote How Children
Develop to describe this ever improving body of knowledge of children and their development and to convey our
excitement about the progress that is being made in understanding the developmental process. We are pleased to
continue this endeavor with the publication of the Fourth Edition of How Children Develop.
—From the Preface
As new research expands the field’s understanding of child and adolescent development, the authors of How Chil-
dren Develop continue their commitment to bringing the story of today’s developmental science to the classroom in
a clear and memorable way. Joined in this Fourth Edition by Jenny Saffran of the University of Wisconsin–Madison,
they maintain their signature emphasis on the “Seven Classic Themes” of development, which facilitates students’
understanding by highlighting the fundamental questions posed by investigators past and present. The new and ex-
panded coverage in the Fourth Edition spans a wide range of topics—from broad areas like the epigenetic aspects
of development, the links between brain function and behavior, and the pervasive influence of culture to specific
subjects such as the mechanisms of infants’ learning, the effects of math anxiety, and the rapidly growing influence
of social media in children’s and adolescents’ lives. This edition also features the highly anticipated debut of Launch-
Pad, an online learning system that features Worth Publishers’ celebrated video collection; the full e-Book of How
Children Develop; and the LearningCurve quizzing system, which offers students instant feedback on their learning.
Learn more about and request access at www.worthpublishers.com/launchpad.
Order How Children Develop, Fourth Edition, with LaunchPad at no additional cost by using
ISBN 10: 1-4641-8284-1 / ISBN-13: 978-1-4641-8284-6.
Coverage of contemporary developmental science is very important to me. I prefer a text that describes the relevant
research and is updated regularly. I find How Children Develop to be very good in this area, as all of the authors are
primarily researchers.
—Jeffery Gagne, University of Texas at Arlington
I highly recommend this textbook. The main strengths are up-to-date research with clear descriptions of study
methods and findings as well as excellent real-world examples that get students interested in a topic so that they are
excited enough to read about the research and evidence that support real-world developmental phenomenon. I do
not think the text has a major weakness.
—Katherine O’Doherty, Bowdoin College
Since its inception, I think that How Children Develop is the best child development textbook available. I would not
hesitate to use it again in my classes.
—Richard Lanthier, George Washington University
www.worthpublishers.com
Cover art: Football, Bentota, Sri Lanka, 1998 (oil on canvas)
©Andrew Macara / Private Collection / The Bridgeman Art Library
develop
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W O R T H
F o u r t h
E d i t i o n
Siegler
DeLoache
Eisenberg
Saffran

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develop
How Children

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develop
How Children
F o u r t h E d i t i o n
Robert Siegler
Carnegie Mellon University
Judy DeLoache
University of Virginia
Nancy Eisenberg
Arizona State University
Jenny Saffran
University of Wisconsin–Madison
And Campbell Leaper,
University of California–Santa Cruz, reviser of Chapter 15: Gender Development

This is dedicated to the ones we love
Senior Vice President, Editorial and Production: Catherine Woods
Publisher: Kevin Feyen
Senior Acquisitions Editor: Daniel DeBonis
Development Editor: Peter Deane
Assistant Editor: Nadina Persaud
Executive Marketing Manager: Katherine Nurre
Associate Director of Market Research: Carlise Stembridge
Executive Media Editor: Rachel Comerford
Media Editor: Lauren Samuelson
Associate Media Editor: Anthony Casciano
Director of Development for Print and Digital Products: Tracey Kuehn
Associate Managing Editor: Lisa Kinne
Senior Project Editor: Vivien Weiss
Production Manager: Sarah Segal
Art Director: Barbara Reingold
Senior Designer: Kevin Kall
Cover Designer: Diana Andrews
Interior Text Designer: Lissi Sigillo
Photo Editor: Bianca Moscatelli
Photo Researcher: Elyse Rieder
Art Manager: Matt McAdams
Illustrations: Todd Buck Illustration; Precision Graphics; TSI Graphics, Inc.; MPS Ltd.
Composition: Northeastern Graphic
Printing and Binding: Quad/Graphics, Versailles
Library of Congress Control Number: 2013952245
ISBN-10: 1-4292-4231-0
ISBN-13: 978-1-4292-4231-8
© 2014, 2011, 2006, 2003 by Worth Publishers
All rights reserved.
Printed in the United States of America
First printing
Worth Publishers
41 Madison Avenue
New York, NY 10010
www.worthpublishers.com

about the authors:
Robert Siegler is the Teresa Heinz Professor of Cognitive Psychology at Carnegie
Mellon University. He is author of the cognitive development textbook Children’s
Thinking and has written or edited several additional books on child development. His
books have been translated into Japanese, Chinese, Korean, Spanish, French, Greek,
Hebrew, and Portuguese. In the past few years, he has presented keynote addresses at
the conventions of the Cognitive Development Society, the International Society for the
Study of Behavioral Development, the Japanese Psychological Association, the Eastern
Psychological Association, the American Psychological Society, and the Conference on
Human Development. He also has served as Associate Editor of the journal Developmental
Psychology, co-edited the cognitive development volume of the 2006 Handbook of Child
Psychology, and served on the National Mathematics Advisory Panel from 2006 to 2008.
Dr. Siegler received the American Psychological Association’s Distinguished Scientific
Contribution Award in 2005, was elected to the National Academy of Education in 2010,
and was named Director of the Siegler Center for Innovative Learning at Beijing Normal
University in 2012.
Judy DeLoache is the William R. Kenan Jr. Professor of Psychology at the University
of Virginia. She has published extensively on aspects of cognitive development in infants
and young children. Dr. DeLoache has served as President of the Developmental Division
of the American Psychological Association, as President of the Cognitive Development
Society, and as a member of the executive board of the International Society for the Study of
Infancy. She has presented major invited addresses at professional meetings, including the
Association for Psychological Science and the Society for Research in Child Development.
Dr. DeLoache is the holder of a Scientific MERIT Award from the National Institutes
of Health, and her research is also funded by the National Science Foundation. She has
been a visiting fellow at the Center for Advanced Study in the Behavioral Sciences in
Palo Alto, California, and at the Rockefeller Foundation Study Center in Bellagio, Italy.
She is a Fellow of the National Academy of Arts and Sciences. In 2013, she received
the Distinguished Research Contributions Award from the Society for Research in Child
Development and the William James Award for Distinguished Contributions to Research
from the Association for Psychological Science.
Nancy Eisenberg is Regents’ Professor of Psychology at Arizona State University.
Her research interests include social, emotional, and moral development, as well as so-
cialization influences, especially in the areas of self-regulation and adjustment. She has
published numerous empirical studies, as well as books and chapters on these topics.
She has also been editor of Psychological Bulletin and the Handbook of Child Psychology
and was the founding editor of the Society for Research in Child Development journal
Child Development Perspectives. Dr. Eisenberg has been a recipient of Research Scientist
Development Awards and a Research Scientist Award from the National Institutes of
Health (NICHD and NIMH). She has served as President of the Western Psychological
Association and of Division 7 of the American Psychological Association and is president-
elect of the Association for Psychological Science. She is the 2007 recipient of the Ernest
R. Hilgard Award for a Career Contribution to General Psychology, Division 1, American
Psychological Association; the 2008 recipient of the International Society for the Study
of Behavioral Development Distinguished Scientific Contribution Award; the 2009 re-
cipient of the G. Stanley Hall Award for Distinguished Contribution to Developmental
Psychology, Division 7, American Psychological Association; and the 2011 William James

vi
Fellow Award for Career Contributions in the Basic Science of Psychology from the
Association for Psychological Science.
Jenny R. Saffran is the College of Letters & Science Distinguished Professor of
Psychology at the University of Wisconsin–Madison, and an investigator at the Waisman
Center. Her research is focused on learning in infancy and early childhood, with a particular
focus on language. Dr. Saffran currently holds a MERIT award from the Eunice Kennedy
Shriver National Institute of Child Health and Human Development. She has been the
recipient of numerous awards for her scientific research, including the Boyd McCandless
Award from the American Psychological Association for early career contributions to
developmental psychology, and the Presidential Early Career Award for Scientists and
Engineers from the National Science Foundation.

vii
Preface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xx
1 An Introduction to Child Development . . . . . . . . . . . . . . . . . . 1
2 Prenatal Development and the Newborn Period . . . . . . . . . . . 39
3 Biology and Behavior . . . . . . . . . . . . . . . . . . . . . . . . . . 85
4 Theories of Cognitive Development . . . . . . . . . . . . . . . . . 129
5 Seeing, Thinking, and Doing in Infancy . . . . . . . . . . . . . . . . 171
6 Development of Language and Symbol Use . . . . . . . . . . . . . 215
7 Conceptual Development . . . . . . . . . . . . . . . . . . . . . . . 259
8 Intelligence and Academic Achievement . . . . . . . . . . . . . . . 297
9 Theories of Social Development . . . . . . . . . . . . . . . . . . . 339
10 Emotional Development . . . . . . . . . . . . . . . . . . . . . . . . 383
11 Attachment to Others and Development of Self . . . . . . . . . . 425
12 The Family . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 467
13 Peer Relationships . . . . . . . . . . . . . . . . . . . . . . . . . . . . 509
14 Moral Development . . . . . . . . . . . . . . . . . . . . . . . . . . . 553
15 Gender Development . . . . . . . . . . . . . . . . . . . . . . . . . . 593
16 Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 637
Glossary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . G-1
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . R-1
Name Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . NI-1
Subject Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . SI-1
brief contents:

viii
Preface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xx
Chapter 1 An Introduction to Child Development . . . . . . 1
Reasons to Learn About Child Development . . . . . . . . . . . . . . . . 3
Raising Children 3
Choosing Social Policies 4
Understanding Human Nature 6
Review 7
Historical Foundations of the Study of Child Development . . . . . . . . 7
Early Philosophers’ Views of Children’s Development 8
Social Reform Movements 9
Darwin’s Theory of Evolution 9
The Beginnings of Research-Based Theories of Child Development 10
Review 10
Enduring Themes in Child Development . . . . . . . . . . . . . . . . . . . 10
1 . Nature and Nurture: How Do Nature and Nurture Together Shape
Development? 10
2 . The Active Child: How Do Children Shape Their Own
Development? 12
3 . Continuity/Discontinuity: In What Ways Is Development Continuous,
and in What Ways Is It Discontinuous? 13
4 . Mechanisms of Development: How Does Change Occur? 16
5 . The Sociocultural Context: How Does the Sociocultural Context
Influence Development? 17
6 . Individual Differences: How Do Children Become So Different
from One Another? 20
7 . Research and Children’s Welfare: How Can Research Promote
Children’s Well-Being? 21
Review 22
Methods for Studying Child Development . . . . . . . . . . . . . . . . . 22
The Scientific Method 23
Contexts for Gathering Data About Children 25
Correlation and Causation 28
Designs for Examining Development 32
Ethical Issues in Child-Development Research 35
Review 36
contents:

ix
Chapter 2 Prenatal Development and
the Newborn Period . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
Prenatal Development . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
Box 2.1: A Closer look Beng Beginnings 41
Conception 42
Box 2.2: Individual differences The First—and Last—Sex Differences 44
Developmental Processes 45
Box 2.3: A Closer look Phylogenetic Continuity 46
Early Development 47
An Illustrated Summary of Prenatal Development 48
Fetal Behavior 51
Fetal Experience 52
Fetal Learning 54
Hazards to Prenatal Development 56
Box 2.4: Applications Face Up to Wake Up 61
Review 66
The Birth Experience . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66
Diversity of Childbirth Practices 68
Review 69
The Newborn Infant . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70
State of Arousal 70
Negative Outcomes at Birth 74
Box 2.5: Applications Parenting a Low-Birth-Weight Baby 78
Review 81
Chapter 3 Biology and Behavior . . . . . . . . . . . . . . . . . 85
Nature and Nurture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87
Genetic and Environmental Forces 88
Box 3.1: Applications Genetic Transmission of Disorders 94
Behavior Genetics 99
Box 3.2: Individual differences Identical Twins Reared Apart 101
Review 105
Brain Development . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106
Structures of the Brain 106
Developmental Processes 109
Box 3.3: A Closer look Mapping the Mind 110
The Importance of Experience 114
Brain Damage and Recovery 117
Review 118
The Body: Physical Growth and Development . . . . . . . . . . . . . . . 119
Growth and Maturation 119

x
Nutritional Behavior 121
Review 126
Chapter 4 Theories of Cognitive Development . . . . . . . 129
Piaget’s Theory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 132
View of Children’s Nature 132
Central Developmental Issues 133
The Sensorimotor Stage (Birth to Age 2 Years) 135
The Preoperational Stage (Ages 2 to 7) 138
The Concrete Operational Stage (Ages 7 to 12) 141
The Formal Operational Stage (Age 12 and Beyond) 141
Piaget’s Legacy 142
Box 4.1: Applications Educational Applications of Piaget’s Theory 143
Review 144
Information-Processing Theories . . . . . . . . . . . . . . . . . . . . . . 145
View of Children’s Nature 146
Central Developmental Issues 147
Box 4.2: Applications Educational Applications of Information-Processing
Theories 154
Review 155
Sociocultural Theories . . . . . . . . . . . . . . . . . . . . . . . . . . . . 155
View of Children’s Nature 156
Central Developmental Issues 158
Review 160
Box 4.3: Applications Educational Applications of Sociocultural Theories 161
Dynamic-Systems Theories . . . . . . . . . . . . . . . . . . . . . . . . . 161
View of Children’s Nature 163
Central Development Issues 165
Box 4.4: Applications Educational Applications of Dynamic-Systems
Theories 166
Review 167
Chapter 5 Seeing, Thinking, and Doing in Infancy . . . . . 171
Perception . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 173
Vision 173
Box 5.1: A Closer look Infants’ Face Perception 176
Box 5.2: A Closer look Picture Perception 183
Auditory Perception 182
Taste and Smell 186
Touch 186
Intermodal Perception 186
Review 188

xi
Motor Development . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 188
Reflexes 189
Motor Milestones 190
Current Views of Motor Development 191
Box 5.3: A Closer look “The Case of the Disappearing Reflex” 192
The Expanding World of the Infant 192
Box 5.4: Applications A Recent Secular Change in Motor Development 195
Box 5.5: A Closer look “Gangway—I’m Coming Down” 196
Review 198
Learning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 198
Habituation 199
Perceptual Learning 199
Statistical Learning 200
Classical Conditioning 201
Instrumental Conditioning 201
Observational Learning/Imitation 202
Rational Learning 204
Review 205
Cognition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 205
Object Knowledge 206
Physical Knowledge 207
Social Knowledge 208
Looking Ahead 211
Review 211
Chapter 6 Development of Language and
Symbol Use . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 215
Language Development . . . . . . . . . . . . . . . . . . . . . . . . . . . . 216
The Components of Language 217
What Is Required for Language? 218
Box 6.1: Applications Two Languages Are Better Than One 222
The Process of Language Acquisition 224
Box 6.2: Individual differences The Role of Family and School Context
in Early Language Development 235
Box 6.3: Applications: iBabies: Technology and Language Learning 240
Theoretical Issues in Language Development 246
Box 6.4: A Closer look: “I Just Can’t Talk Without My Hands” What Gestures
Tell Us About Language 248
Box 6.5: Individual differences Developmental Language Disorders 251
Review 252
Nonlinguistic Symbols and Development . . . . . . . . . . . . . . . . . 252
Using Symbols as Information 253
Drawing 254
Review 256

xii
Chapter 7 Conceptual Development . . . . . . . . . . . . . 259
Understanding Who or What . . . . . . . . . . . . . . . . . . . . . . . . 261
Dividing Objects into Categories 261
Knowledge of Other People and Oneself 266
Box 7.1: Individual differences Children with Autism Spectrum
Disorders (ASD) 270
Box 7.2: Individual differences Imaginary Companions 273
Knowledge of Living Things 273
Review 278
Understanding Why, Where, When, and How Many . . . . . . . . . . . 278
Causality 279
Box 7.3: A Closer look Magical Thinking and Fantasy 282
Space 283
Time 286
Number 288
Relations Among Understanding of Space, Time, and Number 292
Review 293
Chapter 8 Intelligence and Academic Achievement . . . 297
What Is Intelligence? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 299
Intelligence as a Single Trait 299
Intelligence as a Few Basic Abilities 299
Intelligence as Numerous Processes 300
A Proposed Resolution 300
Review 301
Measuring Intelligence . . . . . . . . . . . . . . . . . . . . . . . . . . . . 301
The Contents of Intelligence Tests 302
The Intelligence Quotient (IQ) 304
Continuity of IQ Scores 305
Box 8.1: Individual differences Gifted Children 306
Review 306
IQ Scores as Predictors of Important Outcomes . . . . . . . . . . . . . 307
Review 308
Genes, Environment, and the Development of Intelligence . . . . . . . 308
Qualities of the Child 309
Influence of the Immediate Environment 310
Influence of Society 313
Box 8.2: Applications: A Highly Successful Early Intervention: The Carolina
Abecedarian Project 318
Review 320
Alternative Perspectives on Intelligence . . . . . . . . . . . . . . . . . . 320
Review 322

xiii
Acquisition of Academic Skills: Reading, Writing,
and Mathematics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 322
Reading 322
Box 8.3: Individual differences Dyslexia 326
Writing 328
Mathematics 330
Mathematics Anxiety 334
Box 8.4: Applications Mathematics Disabilities 335
Review 335
Chapter 9 Theories of Social Development . . . . . . . . . 339
Psychoanalytic Theories . . . . . . . . . . . . . . . . . . . . . . . . . . . 341
View of Children’s Nature 342
Central Developmental Issues 342
Freud’s Theory of Psychosexual Development 342
Erikson’s Theory of Psychosocial Development 345
Current Perspectives 347
Review 348
Learning Theories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 348
View of Children’s Nature 349
Central Developmental Issues 349
Watson’s Behaviorism 349
Skinner’s Operant Conditioning 350
Social Learning Theory 352
Box 9.1: A Closer look Bandura and Bobo 352
Current Perspectives 355
Review 356
Theories of Social Cognition . . . . . . . . . . . . . . . . . . . . . . . . . 356
View of Children’s Nature 356
Central Developmental Issues 356
Selman’s Stage Theory of Role Taking 357
Dodge’s Information-Processing Theory of Social Problem Solving 357
Dweck’s Theory of Self-Attributions and Achievement Motivation 359
Current Perspectives 361
Review 361
Ecological Theories of Development . . . . . . . . . . . . . . . . . . . . 362
View of Children’s Nature 362
Central Developmental Issues 362
Ethological and Evolutionary Theories 362
The Bioecological Model 366
Box 9.2: Individual differences Attention-Deficit Hyperactivity Disorder 370
Box 9.3: Applications Preventing Child Abuse 373
Current Perspectives 378
Review 379

xiv
Chapter 10 Emotional Development . . . . . . . . . . . . . 383
The Development of Emotions in Childhood . . . . . . . . . . . . . . . 385
Theories on the Nature and Emergence of Emotion 386
The Emergence of Emotion in the Early Years and Childhood 387
Box 10.1: Individual differences Gender Differences in Adolescent
Depression 396
Review 398
Regulation of Emotion . . . . . . . . . . . . . . . . . . . . . . . . . . . . 398
The Development of Emotional Regulation 399
The Relation of Emotional Self-Regulation to Social Competence and
Adjustment 401
Review 402
Individual Differences in Emotion and Its Regulation . . . . . . . . . . . 402
Temperament 403
Box 10.2: A Closer look Measurement of Temperament 406
Review 410
Children’s Emotional Development in the Family . . . . . . . . . . . . . 410
Quality of the Child’s Relationships with Parents 410
Parental Socialization of Children’s Emotional Responding 411
Review 414
Culture and Children’s Emotional Development . . . . . . . . . . . . . . 414
Review 416
Children’s Understanding of Emotion . . . . . . . . . . . . . . . . . . . . 416
Identifying the Emotions of Others 416
Understanding the Causes and Dynamics of Emotion 418
Children’s Understanding of Real and False Emotions 419
Review 421
Chapter 11 Attachment to Others and
Development of Self . . . . . . . . . . . . . . . . . . . . . . . . . . 425
The Caregiver–Child Attachment Relationship . . . . . . . . . . . . . . 427
Attachment Theory 428
Measurement of Attachment Security in Infancy 430
Box 11.1: Individual differences Parental Attachment Status 432
Cultural Variations in Attachment 434
Factors Associated with the Security of Children’s Attachment 435
Box 11.2: Applications Interventions and Attachment 436
Does Security of Attachment Have Long-Term Effects? 437
Review 439
Conceptions of the Self . . . . . . . . . . . . . . . . . . . . . . . . . . . 439
The Development of Conceptions of Self 440

xv
Identity in Adolescence 446
Review 449
Ethnic Identity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 449
Ethnic Identity in Childhood 450
Ethnic Identity in Adolescence 451
Review 453
Sexual Identity or Orientation . . . . . . . . . . . . . . . . . . . . . . . . 453
The Origins of Youths’ Sexual Identity 453
Sexual Identity in Sexual-Minority Youth 454
Review 458
Self-Esteem . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 458
Sources of Self-Esteem 459
Self-Esteem in Minority Children 462
Culture and Self-Esteem 463
Review 464
Chapter 12 The Family . . . . . . . . . . . . . . . . . . . . . . . 467
Family Dynamics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 470
Box 12.1: A Closer look Parent–Child Relationships
in Adolescence 471
Review 472
The Role of Parental Socialization . . . . . . . . . . . . . . . . . . . . . . 472
Parenting Styles and Practices 472
The Child as an Influence on Parenting 477
Socioeconomic Influences on Parenting 479
Box 12.2: A Closer look Homelessness 481
Review 482
Mothers, Fathers, and Siblings . . . . . . . . . . . . . . . . . . . . . . . . 482
Differences in Mothers’ and Fathers’ Interactions with Their
Children 482
Sibling Relationships 483
Review 485
Changes in Families in the United States . . . . . . . . . . . . . . . . . . 485
Box 12.3: Individual differences Adolescents as Parents 486
Older Parents 488
Divorce 489
Stepparenting 494
Lesbian and Gay Parents 496
Review 497
Maternal Employment and Child Care . . . . . . . . . . . . . . . . . . . 498
The Effects of Maternal Employment 498
The Effects of Child Care 500
Review 506

xvi
Chapter 13 Peer Relationships . . . . . . . . . . . . . . . . . . 509
What Is Special About Peer Relationships? . . . . . . . . . . . . . . . . 512
Friendships . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 513
Early Peer Interactions and Friendships 513
Developmental Changes in Friendship 515
The Functions of Friendships 517
Effects of Friendships on Psychological Functioning and Behavior
over Time 520
Box 13.1: Individual differences Culture and Children’s Peer
Experience 522
Children’s Choice of Friends 523
Review 525
Peers in Groups . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 525
The Nature of Young Children’s Groups 525
Cliques and Social Networks in Middle Childhood and Early
Adolescence 526
Cliques and Social Networks in Adolescence 526
Negative Influences of Cliques and Social Networks 528
Box 13.2: A Closer look Cyberspace and Children’s Peer Experience 529
Romantic Relationships with Peers 531
Review 532
Status in the Peer Group . . . . . . . . . . . . . . . . . . . . . . . . . . . 532
Measurement of Peer Status 533
Characteristics Associated with Sociometric Status 533
Box 13.3: Applications Fostering Children’s Peer Acceptance 538
Stability of Sociometric Status 539
Cross-Cultural Similarities and Differences in Factors Related to
Peer Status 539
Peer Status as a Predictor of Risk 540
Review 543
The Role of Parents in Children’s Peer Relationships . . . . . . . . . . . 544
Relations Between Attachment and Competence with Peers 544
Quality of Ongoing Parent–Child Interactions and
Peer Relationships 545
Parental Beliefs 546
Gatekeeping and Coaching 546
Family Stress and Children’s Social Competence 548
Review 548
Chapter 14 Moral Development . . . . . . . . . . . . . . . . 553
Moral Judgment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 555
Piaget’s Theory of Moral Judgment 555
Kohlberg’s Theory of Moral Judgment 558

xvii
Prosocial Moral Judgment 562
Domains of Social Judgment 563
Review 566
The Early Development of Conscience . . . . . . . . . . . . . . . . . . . 566
Factors Affecting the Development of Conscience 567
Review 568
Prosocial Behavior . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 568
The Development of Prosocial Behavior 569
The Origins of Individual Differences in Prosocial Behavior 571
Box 14.1: A Closer look Cultural Contributions to Children’s Prosocial
and Antisocial Tendencies 573
Box 14.2: Applications School-Based Interventions for Promoting
Prosocial Behavior 576
Review 577
Antisocial Behavior . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 577
The Development of Aggression and Other Antisocial Behaviors 577
Consistency of Aggressive and Antisocial Behavior 579
Box 14.3: A Closer look Oppositional Defiant Disorder and
Conduct Disorder 580
Characteristics of Aggressive-Antisocial Children and Adolescents 581
The Origins of Aggression 582
Biology and Socialization: Their Joint Influence on Children’s Antisocial
Behavior 587
Box 14.4: Applications The Fast Track Intervention 588
Review 589
Chapter 15 Gender Development . . . . . . . . . . . . . . . 593
Theoretical Approaches to Gender Development . . . . . . . . . . . . 595
Biological Influences 596
Box 15.1: A Closer look: Gender Identity: More than Socialization? 598
Cognitive and Motivational Influences 599
Box 15.2: A Closer look Gender Typing at Home 604
Box 15.3: Applications Where Are SpongeSally SquarePants and
Curious Jane? 605
Cultural Influences 606
Review 607
Milestones in Gender Development . . . . . . . . . . . . . . . . . . . . 607
Infancy and Toddlerhood 608
Preschool Years 608
Middle Childhood 610
Adolescence 612
Box 15.4: A Closer look Gender Flexibility and Asymmetry 613
Review 614

xviii
Comparing Girls and Boys . . . . . . . . . . . . . . . . . . . . . . . . . . 614
Physical Growth: Prenatal Development Through Adolescence 617
Cognitive Abilities and Academic Achievement 619
Personality Traits 625
Interpersonal Goals and Communication 626
Box 15.5: A Closer look Gender and Children’s Communication Styles 627
Aggressive Behavior 628
Box 15.6: Applications Sexual Harassment and Dating Violence 631
Review 633
Chapter 16 Conclusions . . . . . . . . . . . . . . . . . . . . . . . 637
Theme 1: Nature and Nurture: All Interactions, All the Time . . . . . . . 638
Nature and Nurture Begin Interacting Before Birth 638
Infants’ Nature Elicits Nurture 639
Timing Matters 639
Nature Does Not Reveal Itself All at Once 640
Everything Influences Everything 641
Theme 2: Children Play Active Roles in Their Own Development . . . . 641
Self-Initiated Activity 642
Active Interpretation of Experience 643
Self-Regulation 643
Eliciting Reactions from Other People 644
Theme 3: Development Is Both Continuous and Discontinuous . . . . . 645
Continuity/Discontinuity of Individual Differences 645
Continuity/Discontinuity of Overall Development: The Question
of Stages 646
Theme 4: Mechanisms of Developmental Change . . . . . . . . . . . . 648
Biological Change Mechanisms 648
Behavioral Change Mechanisms 649
Cognitive Change Mechanisms 651
Change Mechanisms Work Together 653
Theme 5: The Sociocultural Context Shapes Development . . . . . . . 653
Growing Up in Societies with Different Practices and Values 653
Growing Up in Different Times and Places 655
Growing Up in Different Circumstances Within a Society 655
Theme 6: Individual Differences . . . . . . . . . . . . . . . . . . . . . . . 656
Breadth of Individual Differences at a Given Time 657
Stability Over Time 658
Predicting Future Individual Differences on Other Dimensions 658
Determinants of Individual Differences 659
Theme 7: Child-Development Research Can Improve
Children’s Lives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 660

xix
Implications for Parenting 660
Implications for Education 662
Implications for Helping Children at Risk 662
Improving Social Policy 664
Glossary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . G-1
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . R-1
Name Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . NI-1
Subject Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . SI-1

xx
This is an exciting time in the field of child development. The past decade has
brought new theories, new ways of thinking, new areas of research, and innumera-
ble new findings to the field. We originally wrote How Children Develop to describe
this ever-improving body of knowledge of children and their development and to
convey our excitement about the progress that is being made in understanding the
developmental process. We are pleased to continue this endeavor with the publica-
tion of the fourth edition of How Children Develop.
As teachers of child development courses, we appreciate the challenge that in-
structors face in trying to present these advances and discoveries—as well as the
major older ideas and findings—in a one-semester course. Therefore, rather than
aim at encyclopedic coverage, we have focused on identifying the most important
developmental phenomena and describing them in sufficient depth to make them
meaningful and memorable to students. In short, our goal has been to write a text-
book that makes the child development course coherent and enjoyable for students
and teachers alike.
Classic Themes
The basic premise of the book is that all areas of child development are unified by a
small set of enduring themes. These themes can be stated in the form of questions
that child development research tries to answer:
1. How do nature and nurture together shape development?
2. How do children shape their own development?
3. In what ways is development continuous and in what ways is it
discontinuous?
4. How does change occur?
5. How does the sociocultural context influence development?
6. How do children become so different from one another?
7. How can research promote children’s well-being?
These seven themes provide the core structure of the book. They are introduced
and illustrated in Chapter 1, highlighted repeatedly, where relevant, in the subse-
quent fourteen content chapters, and utilized in the final chapter as a framework
for integrating findings relevant to each theme from all areas of development. The
continuing coverage of these themes allows us to tell a story that has a beginning
(the introduction of the themes), a middle (discussion of specific findings relevant
to them), and an ending (the overview of what students have learned about the
themes). We believe that this thematic emphasis and structure will not only help
students to understand enduring questions about child development but will also
leave them with a greater sense of satisfaction and completion at the end of the
course.
preface:

xxi
Contemporary Perspective
The goal of providing a thoroughly contemporary perspective on how children
develop has influenced the organization of our book as well as its contents. Whole
new areas and perspectives have emerged that barely existed when most of today’s
child development textbooks were originally written. The organization of How
Children Develop is designed to present these new topics and approaches in the
context of the field as it currently stands, rather than trying to shoehorn them into
organizations that once fit the field but no longer do.
Consider the case of Piaget’s theory and current research relevant to it. Piaget’s
theory often is presented in its own chapter, most of which describes the theory
in full detail and the rest of which offers contemporary research that demonstrates
problems with the theory. This approach often leaves students wondering why so
much time was spent on Piaget’s theory if modern research shows it to be wrong
in so many ways.
The fact is that the line of research that began over 40 years ago as an effort to
challenge Piaget’s theory has emerged since then as a vital area in its own right—
the area of conceptual development. Research in conceptual development provides
extensive information on such fascinating topics as children’s understanding of
human beings, plants and animals, and the physical universe. As with other re-
search areas, most studies in this field are aimed primarily at uncovering evidence
relevant to current claims, not those of Piaget.
We adapted to this changing intellectual landscape in two ways. First, our chap-
ter “Theories of Cognitive Development” (Chapter 4) describes the fundamental
aspects of Piaget’s theory in depth and honors his legacy by focusing on the aspects
of his work that have proven to be the most enduring. Second, a first-of-its-kind
chapter called “Conceptual Development” (Chapter 7) addresses the types of issues
that inspired Piaget’s theory but concentrates on modern perspectives and findings
regarding those issues. This approach allows us to tell students about the numerous
intriguing proposals and observations that are being made in this field, without the
artificiality of classifying the findings as “pro-Piagetian” or “anti-Piagetian.”
The opportunity to create a textbook based on current understanding also led
us to assign prominent positions to such rapidly emerging areas as epigenetics,
behavioral genetics, brain development, prenatal learning, infant cognition, acquisi-
tion of academic skills, emotional development, prosocial behavior, and friendship
patterns. All these areas have seen major breakthroughs in recent years, and their
growing prominence has led to even greater emphasis on them in this edition.
Getting Right to the Point
Our desire to offer a contemporary, streamlined approach led to other departures
from the traditional organization. It is our experience that today’s students take
child development courses for a variety of practical reasons and are eager to learn
about children. Traditionally, however, they have had to wait two or three or even
four chapters—on the history of the field, on major theories, on research methods,
on genetics—before actually getting to the study of children. We wanted to build
on their initial motivation from the start.
Rather than beginning the book, then, with an extensive examination of the his-
tory of the field, we include in Chapter 1 a brief overview of the social and intel-
lectual context in which the scientific study of children arose and provide historical

xxii
background wherever it is pertinent in subsequent chapters. Rather than have an
early “blockbuster” theories chapter that covers all the major cognitive and social
theories at once (at a point far removed from the content chapters to which the
theories apply), we present a chapter on cognitive developmental theories just before
the chapters that focus on specific aspects of cognitive development, and we simi-
larly present a chapter on social developmental theories just before the chapters that
focus on specific aspects of social development. Rather than have a separate chapter
on genetics, we include basic aspects of genetics as part of Chapter 3, “Biology and
Behavior,” and then discuss the contributions of genetics to some of the differences
among individuals throughout the book. When we originally chose this organization,
we hoped that it would allow us, from the first weeks of the course, to kindle students’
enthusiasm for finding out how children develop. Judging by the overwhelmingly
positive response we have received from students and instructors alike, it has.
Features
The most important feature of this book is the exposition, which we have tried to
make as clear, compelling, and interesting as possible. As in previous editions, we
have given extra attention to making it accessible to a broad range of students.
To further enhance the appeal and accessibility of the text, we have re-
tained three types of discussion boxes that explore topics of special interest.
“Applications” boxes focus on how child development research can be used to
promote children’s well-being. Among the applications that are summed up in
these boxes are board-game procedures for improving preschoolers’ understand-
ing of numbers; the Carolina Abecedarian Project; interventions to reduce child
abuse; programs, such as PATHS, for helping rejected children gain acceptance
from their peers; and Fast Track interventions, which help aggressive children
learn how to manage their anger and antisocial behavior. “Individual Differences”
boxes focus on populations that differ from the norm with regard to the specific
topic under consideration, or on variations among children in the general popu-
lation. Some of these boxes highlight developmental problems such as autism,
ADHD, dyslexia, specific language impairment, and conduct disorder, while oth-
ers focus on differences in the development of children that center on attachment
status, gender, and cultural differences. “A Closer Look” boxes examine important
and interesting research in greater depth than would otherwise be possible: the
areas examined range from brain imaging techniques to discrepant gender iden-
tity to the developmental impact of homelessness.
We have also retained a number of other features intended to improve students’
learning. These features include boldfacing key terms and supplying definitions
both within the immediate text and in marginal glossaries; providing summaries at
the end of each major section, as well as summaries for the overall chapter; and,
at the end of each chapter, posing critical thinking questions intended to promote
deeper consideration of essential topics.
New to the Fourth Edition
We have expanded our coverage of a number of research areas that have become
increasingly important in recent years for both the students of child development
and the instructors who teach it. In the following paragraphs, we outline some of

xxiii
the highlights of the fourth edition. Thank you for taking the time to look through
this new edition of How Children Develop. We hope that you find it to be useful
and appealing.
New and Expanded Coverage
In selecting what to cover from among the many new discoveries about child de-
velopment, we have emphasized the studies that strike us as the most interesting
and important. While retaining and thoroughly updating its essential coverage, the
fourth edition of How Children Develop continues to explore a number of fascinat-
ing areas in which there has been great progress in the past few years. Following is
a very brief sampling of the many areas of new and expanded coverage:
n Epigenetics
n Gene–environment relations, including methylation
n The role of specific gene variants in certain behaviors
n Differential susceptibility to the environment
n Brain development and functioning
n Mechanisms of infants’ learning
n Infants’ understanding of other people
n Executive functioning
n Cultural influences on development
n Relations among understanding of time, space, and number
n Mathematics anxiety
n Applications of research to education
n The growing role and impact of social media in children’s and adolescents’ lives
n Interventions to foster children’s social adjustment
Supplements
How Children Develop, Fourth Edition, features a wide array of multimedia tools
designed for the individual needs of students and teachers. For more information
about any of the items below, visit Worth Publishers’ online catalog at www. worth
publishers.com.
LaunchPad with LearningCurve Quizzing
A comprehensive Web resource for teaching and learning psychology
LaunchPad combines Worth Publishers’ awarding-winning media with an in-
novative platform for easy navigation. For students, it is the ultimate online study
guide with rich interactive tutorials, videos, e-Book, and the LearningCurve
adaptive quizzing system. For instructors, LaunchPad is a full course space where
class documents can be posted, quizzes are easily assigned and graded, and students’
progress can be assessed and recorded. Whether you are looking for the most effec-
tive study tools or a robust platform for an online course, LaunchPad is a powerful
way to enhance your class.

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LaunchPad for How Children Develop, Fourth
Edition, can be previewed and purchased at http://
www .worthpublishers.com/launchpad/siegler4e.
How Children Develop, Fourth Edition, and
LaunchPad can be ordered together with ISBN 10:
1-4641-8284-1 / ISBN-13: 978-1-4641-8284-6.
LaunchPad for How Children Develop, Fourth Edition,
includes the following resources:
n The LearningCurve quizzing system was designed
based on the latest findings from learning and memory
research. It combines adaptive question selection,
immediate and valuable feedback, and a game-like
interface to engage students in a learning experience that
is unique to them. Each LearningCurve quiz is fully
integrated with other resources in LaunchPad through
the Personalized Study Plan, so students will be able
to review with Worth’s extensive library of videos and
activities. And state-of-the-art question analysis reports
allow instructors to track the progress of individual
students as well as their class as a whole.
n An interactive e-Book allows students to highlight,
bookmark, and make their own notes, just as they
would with a printed textbook. Digital enhancements
include full-text search and in-text glossary definitions.
n Student Video Activities include more than 100
engaging video modules that instructors can easily assign
for student assessment. Videos cover classic experiments,
current news footage, and cutting-edge research, all of
which are sure to spark discussion and encourage critical thinking.
n The Scientific American Newsfeed delivers weekly articles, podcasts, and news
briefs on the very latest developments in psychology from the first name in
popular science journalism.
Additional Student Supplements
CourseSmart e-Book
The CourseSmart e-Book offers the complete text of How Children Develop,
Fourth Edition, in an easy-to-use, flexible format. Students can choose to view
the CourseSmart e-Book online or download it to a personal computer or a por-
table media player, such as a smart phone or iPad. The CourseSmart e-Book for
How Children Develop, Fourth Edition, can be previewed and purchased at www
.coursesmart.com.
Scientific American Reader to Accompany How Children Develop
The authors have compiled fifteen Scientif ic American articles relevant to key top-
ics in the text. The selections range from classics such as Harry Harlow’s “Love in
Infant Monkeys” and Eleanor Gibson and Richard Walk’s “The ‘Visual Cliff ’” to

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xxv
contemporary articles on such topics as the interaction of games and environment
in the development of intelligence (Robert Plomin and John DeFries), the effects
of child abuse on the developing brain (Martin Teicher), balancing work and family
(Robert Pleck), and moral development (William Damon). These articles should
enrich students’ learning and help them to appreciate the process by which devel-
opmental scientists gain new understanding. This premium item can be packaged
with the text at no additional cost.
Take advantage of our most popular supplements!
Worth Publishers is pleased to offer cost-saving packages
of How Children Develop, Fourth Edition, with our most popular
supplements. Below is a list of some of the most popular combinations
available for order through your local bookstore.
How Children Develop, 4th Ed. & LaunchPad Access Card
ISBN 10: 1-4641-8284-1 / ISBN-13: 978-1-4641-8284-6
How Children Develop, 4th Ed. & iClicker
ISBN 10: 1-4641-8283-3 / ISBN-13: 978-1-4641-8283-9
How Children Develop, 4th Ed. & Scientif ic American Reader
ISBN 10: 1-4641-8282-5 / ISBN-13: 978-1-4641-8282-2
How Children Develop, 4th Ed. & Readings on the Development of Children
ISBN 10: 1-4641-8281-7 / ISBN-13: 978-1-4641-8281-5
Presentation and Faculty Support
Presentation Slides
Presentation slides are available in three formats that can be used as they are or
can be customized. One set includes all the textbook’s illustrations and tables. The
second set consists of lecture slides that focus on key themes and terms in the book
and include text illustrations and tables. A third set of PowerPoint slides provides
an easy way to integrate the supplementary video clips into classroom lectures. All
these prebuilt PowerPoint presentations are available through http://www.worth
publishers.com/launchpad/siegler4e.
Presentation Videos
Worth’s video clips for development psychology span the full range of topics for
the child development course. With hundreds of clips to choose from, this pre-
mium collection includes research and news footage on topics ranging from pre-
natal development to the experience of child soldiers to empathy in adolescence.
These clips are made available to instructors for lecturing in the classroom and
also through LaunchPad.
Instructor’s Resource Manual
Written by Lynne Baker-Ward, North Carolina State University, this innovative
Instructor’s Resource Manual includes handouts for student projects, reading lists of
journal articles, course-planning suggestions, and supplementary readings, in addition

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to lecture guides, chapter overviews, and learning objectives.
The Instructor’s Resource Manual can be downloaded at
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New! Faculty Lounge
Faculty Lounge is an online forum provided by Worth
Publishers where teachers can find and share favorite
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Assessment
Test Bank
The Test Bank for How Children Develop by Jill L. Saxon
features 80 multiple-choice and 20 essay questions for each chapter. Each question
is keyed to the textbook by topic, type, and level of difficulty.
Test Bank on CD-ROM
The Diploma Test Bank CD-ROM, on a dual platform for Windows and Macintosh,
guides instructors through the process of creating a test and allows them to add,
edit, and scramble questions; to change formats; and to include pictures, equa-
tions, and media links. The CD-ROM is also the access point for Diploma Online
Testing, which allows creating and administering examinations on paper, over a
network, or over the Internet.
iClicker
The iClicker Classroom Response System is a versatile polling system developed
by educators for educators that makes class time more efficient and interactive.
iClicker allows you to ask questions and instantly record your students’ responses,
take attendance, and gauge students’ understanding and opinions. iClicker is avail-
able at a 10% discount when packaged with How Children Develop, Fourth Edition.
Course Management
Worth Publishers supports multiple Course Management Systems with en-
hanced cartridges for upload into Blackboard, Angel, Desire2Learn, Sakai, and
Moodle (and others upon request). Cartridges are provided free upon adoption
of How Children Develop, Fourth Edition, and can be downloaded through the
catalog page at www.worthpublishers.com.
Acknowledgments
So many people have contributed (directly and indirectly) to this textbook that
it is impossible to know where to start or where to stop in thanking them. All
of us have been given exceptional support by our spouses and significant oth-

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xxvii
ers—Jerry Clore, Jerry Harris, Xiaodong Lin, and Seth Pollak—and by our chil-
dren—Benjamin Clore; Michael Harris; Todd, Beth, and Aaron Siegler; Avianna
McGhee; and Eli and Nell Pollak—as well as by our parents, relatives, friends, and
other loved ones. Our advisors in college and graduate school, Richard Aslin, Ann
Brown, Les Cohen, Harry Hake, Robert Liebert, Jim Morgan, Paul Mussen, Ellisa
Newport, and Jim Pate, helped to launch our careers and taught us how to recog-
nize and appreciate good research. We also have all benefited from collaborators
who shared our quest for understanding child development and from a great many
exceptionally helpful and generous colleagues, including Karen Adolph, Martha
Alibali, Renee Baillargeon, Sharon Carver, Zhe Chen, Richard Fabes, Cindy Fisher,
Melanie Jones, David Klahr, Patrick Lemaire, Angeline Lillard, John Opfer, Kristin
Shutts, Tracy Spinrad, David Uttal, and Carlos Valiente. We owe special thanks to
our assistants, Sheri Towe and Theresa Treasure, who helped in innumerable ways
in preparing the book.
We would also like to thank the many reviewers who contributed to this and
previous editions: Daisuke Akiba, Queens College, City University of New York;
Kimberly Alkins, Queens College, City University of New York; Lynne Baker-
Ward, North Carolina State University; Hilary Barth, Wesleyan University;
Christopher Beevers, Texas University; Martha Bell, Virginia Tech; Cynthia
Berg, University of Utah; Rebecca Bigler, Texas University; Margaret Borkowski,
Saginaw Valley State University; Eric Buhs, University of Nebraska–Lincoln; G.
Leonard Burns, Washington State University; Wendy Carlson, Shenandoah
University; Kristi Cordell-McNulty, Angelo State University; Myra Cox, Harold
Washington College; Emily Davidson, Texas A&M University–Main Campus; Ed
de St. Aubin, Marquette University; Marissa Diener, University of Utah; Sharon
Eaves, Shawnee State University; Urminda Firlan, Grand Rapids Community
College; Dorothy Fragaszy, University of Georgia; Jeffery Gagne, University of
Texas–Austin; Jennifer Ganger, University of Pittsburgh; Alice Ganzel, Cornell
College; Janet Gebelt, Westfield State University; Melissa Ghera, St. John Fisher
College; Susan Graham, University of Calgary; Andrea Greenhoot, University
of Kansas; Frederick Grote, Western Washington University; John Gruszkos,
Reynolds University; Hanna Gustafsson, University of North Carolina; Alma
Guyse, Midland College; Lauren Harris, Michigan State University; Karen
Hartlep, California State University–Bakersfield; Patricia Hawley, University of
Kansas–Main; Susan Hespos, Northwestern University; Doris Hiatt, Monmouth
University; Susan Holt, Central Connecticut State University; Lisa Huffman,
Ball State University; Kathryn Kipp, University of Georgia; Rosemary Krawczyk,
Minnesota State University; Raymond Krukovsky, Union County College;
Tara Kuther, Western Connecticut State University; Richard Lanthier, George
Washington University; Elida Laski, Boston College; Kathryn Lemery, Arizona
State University; Barbara Licht, Florida State University; Angeline Lillard,
University of Virginia; Wayne McMillin, Northwestern State University; Martha
Mendez-Baldwin, Manhattan College; Scott Miller, University of Florida; Keith
Nelson, Pennsylvania State University–Main Campus; Paul Nicodemus, Austin
Peay State University; Katherine O’Doherty, Vanderbilt University; John Opfer,
The Ohio State University; Ann Repp, Texas University; Leigh Shaw, Weber
State University; Jennifer Simonds, Westminster College; Rebekah Smith,
University of Texas–San Antonio; Mark Strauss, University of Pittsburgh–Main;
Spencer Thompson, University of Texas–Permian Basin; Lisa Travis, University
of Illinois Urbana–Champaign; Roger Webb, University of Arkansas–Little Rock;
Keri Weed, University of South Carolina–Aiken; Sherri Widen, Boston College.

xxviii
We would especially like to thank Campbell Leaper, University of California–
Santa Cruz, for his major contributions to the revision of our chapter on gender
development (Chapter 15). We are indebted to Campbell for bringing to the fourth
edition his expertise and keen insight in this important area.
Thanks are particularly due to our friends and collaborators at Worth Publishers.
As acquisitions editor and publisher, respectively, Daniel DeBonis and Kevin Feyen
provided exceptional support and any number of excellent suggestions. We would
also like to thank Marge Byers, who nurtured our first edition from its incep-
tion and helped us to realize our vision. Peter Deane, our development editor, is
in a class by himself in both skill and dedication. Peter’s creative thinking and
firm understanding of the field enhanced the content of the book in innumerable
ways. We are deeply grateful to him. Our thanks go also to assistant editor Nadina
Persaud, senior project editor Vivien Weiss, director of development (print and
digital) Tracey Kuehn, art director Barbara Reingold, cover and text designer Kevin
Kall, photo editor Bianca Moscatelli, photo researcher Elyse Rieder, production
manager Sarah Segal, and compositor Northeastern Graphic for their excellent
work. They have helped to create a book that we hope you will find a pleasure to
look at as well as to read. Marketing manager Katherine Nurre provided outstand-
ing promotional materials to inform professors about the book. Anthony Casciano
and Stacey Alexander managed the superb package of ancillary material.
Finally, we want to thank our “book team” of sales representatives and man-
agers. Tom Kling, Julie Hirshman, Kari Ewalt, Greg David, Tom Scotty, Cindy
Rabinowitz, Glenn Russell, and Matt Dunning provided a sales perspective, valu-
able suggestions, and unflagging enthusiasm throughout this project.

develop
How Children

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D O R OT H E A S H A R P (1874-1955), Young Explorers (oil on canvas)

1
An Introduction
to Child Development
n Reasons to Learn About Child Development
Raising Children
Choosing Social Policies
Understanding Human Nature
Review
n Historical Foundations of the Study
of Child Development
Early Philosophers’ Views of Children’s
Development
Social Reform Movements
Darwin’s Theory of Evolution
The Beginnings of Research-Based Theories
of Child Development
Review
n Enduring Themes in Child Development
1. Nature and Nurture: How Do Nature and Nurture
Together Shape Development?
2. The Active Child: How Do Children Shape Their
Own Development?
3. Continuity/Discontinuity: In What Ways Is
Development Continuous, and in What Ways Is It
Discontinuous?
4. Mechanisms of Development: How Does
Change Occur?
5. The Sociocultural Context: How Does the
Sociocultural Context Influence Development?
6. Individual Differences: How Do Children Become
So Different from One Another?
7. Research and Children’s Welfare: How Can
Research Promote Children’s Well-Being?
Review
n Methods for Studying Child Development
The Scientific Method
Contexts for Gathering Data About Children
Correlation and Causation
Designs for Examining Development
Ethical Issues in Child-Development Research
Review
n Chapter Summary
chapter 1:

2
I
n 1955, a group of child-development researchers began a unique study. Their
goal, like that of many developmental researchers, was to find out how bio-
logical and environmental factors influence children’s intellectual, social, and
emotional growth. What made their study unique was that they examined
these diverse aspects of development for all 698 children born that year on the
Hawaiian island of Kauai and continued studying the children’s development for
more than 30 years.
With the parents’ consent, the research team, headed by Emmy Werner, col-
lected many types of data about the children. To learn about possible complica-
tions during the prenatal period and birth, they examined physicians’ records. To
learn about family interactions and the children’s behavior at home, they arranged
for nurses and social workers to observe the families and to interview the children’s
mothers when the children were 1 year old and again when they were 10 years old.
The researchers also interviewed teachers about the children’s academic perfor-
mance and classroom behavior during the elementary school years and examined
police, family court, and social service records that involved the children, either as
victims or perpetrators. Finally, the researchers administered standardized intelli-
gence and personality tests to the participants when they were 10 and 18 years old
and interviewed them at age 18 and again in their early 30s to find out how they
saw their own development.
Results from this study illustrated some of the many ways in which biological
and environmental factors combine to produce child development. For example,
children who experienced prenatal or birth complications were more likely than
others to develop physical handicaps, mental illness, and learning difficulties. But
whether they developed such problems—and if so, to what degree—depended a
great deal on their home environment. Parents’ income, education, and mental
health, together with the quality of the relationship between the parents, especially
influenced children’s development. By age 2, toddlers who had experienced severe
prenatal or birth problems but who lived in harmonious middle-income families
were nearly as advanced in language and motor skills as were children who had not
experienced such problems. By the time the children were 10-year-olds, prenatal
and birth problems were consistently related to psychological difficulties only if the
children also grew up in poor rearing conditions.
What of children who faced both biological and environmental challenges—
prenatal or birth complications and adverse family circumstances? The majority of
these children developed serious learning or behavior problems by age 10. By age
18, most had acquired a police record, had experienced mental health problems,
or had become an unmarried parent. However, one-third of such at-risk children
showed impressive resilience, growing up into young adults who, in the words of
Werner (1989, p. 108D), “loved well, worked well, and played well.”
Michael was one such resilient child. Born prematurely, with low birth weight,
to teenage parents, he spent the first 3 weeks of his life in a hospital, separated
from his mother. By his 8th birthday, Michael’s parents were divorced, his mother
had deserted the family, and he and his three brothers and sisters were being
raised by their father, with the help of their elderly grandparents. Yet by age 18,
Michael was successful in school, had high self-esteem, was popular with his
peers, and was a caring young man with a positive attitude toward life. The fact
that there are many children like Michael—children who show great resilience
in the face of adversity—is among the most heartening findings of research on
Themes
n Nature and Nurture
n The Active Child
n Continuity/Discontinuity
n Mechanisms of Change
n The Sociocultural Context
n Individual Differences
n Research and Children’s
Welfare

R E A S O N S T O L E A R N A B O U T C H I L D D E V E L O P M E N T n 3
child development. Learning about the Michaels of the world inspires child de-
velopment researchers to conduct further investigations aimed at answering such
questions as why individual children differ so much in their response to similar
environments, and how to apply research findings to help more children overcome
the challenges they face.
Reading this chapter will increase your understanding of these and other basic
questions about child development. It also will introduce you to some historical
perspectives on these fundamental questions and to the perspectives and methods
that modern researchers use to address them. But first, we would like you to con-
sider perhaps the most basic question of all: Why study child development?
Reasons to Learn About Child Development
For us, as both parents and researchers, the sheer enjoyment of watching children
and trying to understand them is reason enough for studying child development.
What could be more fascinating than the development
of a child? But there are also practical and intellectual
reasons for studying child development. Understand-
ing how children develop can improve child-rearing,
promote the adoption of wiser social policies regard-
ing children’s welfare, and answer intriguing questions
about human nature. We examine each of these reasons
in the following sections.
Raising Children
Being a good parent is not easy. Among its many chal-
lenges are the endless questions it raises over the years.
Is it okay to take my infant outside in the cold weather?
Should my baby stay at home, or would going to day
care be better for his social development? If my daughter
starts walking and talking early, should I consider plac-
ing her in a school for gifted children? Should I try to teach my 3-year-old to read
early? My son seems so lonely at preschool; how can I help him make friends? How
can I help my kindergartner deal with her anger?
Child-development research can help answer such questions. For example, one
problem that confronts almost all parents is how to help their children control
their anger and other negative emotions. One tempting, and frequent, reaction
is to spank children who express anger in inappropriate ways, such as fighting,
name-calling, and talking back. In a study involving a representative U.S. sam-
ple, 80% of parents of kindergarten children reported having spanked their child
on occasion, and 27% reported having spanked their child the previous week
( Gershoff et al., 2012). In fact, spanking made the problem worse. The more
often parents spanked their kindergartners, the more often the same children
argued, fought, and acted inappropriately at school when they were 3rd-graders.
This relation held true for Blacks, Whites, Hispanics, and Asians alike, and it
held true above and beyond the effects of other relevant factors, such as parents’
income and education.
Fortunately, research suggests several effective alternatives to spanking
(Denham, 1998, 2006). One is expressing sympathy: when parents respond to their
Will these children be resilient enough to
overcome their disadvantaged environment?
The answer will depend in large part on how
many risk factors they face and on their per-
sonal characteristics.
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4 n chapTer 1 AN INTRODUCTION TO CHILD DEVELOPMENT
children’s distress with sympathy, the children are better able
to cope with the situation causing the distress. Another ef-
fective approach is helping angry children find positive alter-
natives to expressing anger. For example, encouraging them
to do something they enjoy helps them cope with the hostile
feelings.
These strategies and similar ones, such as time-outs, can
also be used effectively by others who contribute to raising
children, such as day-care personnel and teachers. One dem-
onstration of this was provided by a special curriculum that
was devised for helping preschoolers (3- and 4-year-olds) who
were angry and out of control (Denham & Burton, 1996).
With this curriculum, preschool teachers helped children rec-
ognize their own and other children’s emotions, taught them
techniques for controlling their anger, and guided them in
resolving conflicts with other children. One approach that
children were taught for coping with anger was the “turtle
technique.” When children felt themselves becoming angry,
they were to move away from other children and retreat into
their “turtle shell,” where they could think through the situation until they were
ready to emerge from the shell. Posters were placed around the classroom to remind
children of what to do when they became angry.
The curriculum was quite successful. Children who participated in it became
more skillful in recognizing and regulating anger when they experienced it and
were generally less negative. For example, one boy, who had regularly gotten into
fights when angry, told the teacher after a dispute with another child, “See, I used
my words, not my hands” (Denham, 1998, p. 219). The benefits of this program can
be long-term. In one test conducted with children in special education classrooms,
positive effects were still evident 2 years after children completed the curricu-
lum (Greenberg & Kusché, 2006). As this example suggests, knowledge of child-
development research can be helpful to everyone involved in the care of children.
Choosing Social Policies
Another reason to learn about child development is to be able to make informed de-
cisions not just about one’s own children but also about a wide variety of social-policy
questions that affect children in general. For example, how much trust should judges
and juries place in preschoolers’ testimony in child-abuse cases? Should children
who do poorly in school be held back, or should they be promoted to the next
grade so that they can be with children of the same age? How effective are health-
education courses aimed at reducing teenage smoking, drinking, and pregnancy?
Child-development research can inform discussion of all of these policy decisions
and many others.
Consider the issue of how much trust to put in preschoolers’ courtroom tes-
timony. At present, more than 100,000 children testify in legal cases each year
(Bruck, Ceci, & Principe, 2006). Many of these children are very young: more than
40% of children who testify in sexual-abuse trials, for example, are younger than 5
years, and almost 40% of substantiated sexual-abuse cases involve children younger
than age 7 (Bruck et al., 2006; Gray, 1993). The stakes are extremely high in such
cases. If juries believe children who falsely testify that they were abused, innocent
people may spend years in jail. If juries do not believe children who accurately
posters like this are used in the turtle tech-
nique to remind children of ways to control
anger.

R E A S O N S T O L E A R N A B O U T C H I L D D E V E L O P M E N T n 5
report abuse, the perpetrators will go free and probably abuse other children. So
what can be done to promote reliable testimony from young children and to avoid
leading them to report experiences that never occurred?
Psychological research has helped answer such questions. In one experiment, re-
searchers tested whether biased questioning affects the accuracy of young children’s
memory for events involving touching one’s own and other people’s bodies. The re-
searchers began by having 3- to 6-year-olds play a game, similar to “Simon Says,”
in which the children were told to touch various parts of their body and those of
other children. A month later, the researchers had a social worker interview the
children about their experiences during the game (Ceci & Bruck, 1998). Before
the social worker conducted the interviews, she was given a description of each
child’s experiences. Unknown to her, the description included inaccurate as well as
accurate information. For example, she might have been told that a particular child
had touched her own stomach and another child’s nose, when in fact the child had
touched her own stomach and the other child’s foot. After receiving the descrip-
tion, the social worker was given instructions much like those in a court case: “Find
out what the child remembers.”
As it turned out, the version of events that the social worker had heard often in-
fluenced her questions. If, for example, a child’s account of an event was contrary
to what the social worker believed to be the case, she
tended to question the child repeatedly about the event
(“Are you sure you touched his foot? Is it possible you
touched some other part of his body?”). Faced with such
repeated questioning, children fairly often changed their
responses, with 34% of 3- and 4-year-olds eventually
corroborating at least one of the social worker’s incorrect
beliefs. Children were led to “remember” not only plau-
sible events that never happened but also unlikely ones
that the social worker had been told about. For example,
some children “recalled” their knee being licked and a
marble being inserted in their ear.
Studies such as this have yielded a number of con-
clusions regarding children’s testimony in legal pro-
ceedings. One important finding is that when 3- to
5-year-olds are not asked leading questions, their testi-
mony is usually accurate, as far as it goes (Bruck et al.,
2006; Howe & Courage, 1997). However, when prompted by leading questions,
young children’s testimony is often inaccurate, especially when the leading ques-
tions are asked repeatedly. The younger children are, the more susceptible they are
to being led, and the more their recall reflects the biases of the interviewer’s ques-
tions. In addition, realistic props, such as anatomically correct dolls and drawings,
that are often used in judicial cases in the hopes of improving recall of sexual abuse,
do not improve recall of events that occurred; they actually increase the number
of inaccurate claims, perhaps by blurring the line between fantasy play and reality
(Lamb et al., 2008; Poole, Bruck, & Pipe, 2011). Research on child eyewitness tes-
timony has had a large practical impact, leading many judicial and police agencies
to revise their procedures for interviewing child witnesses to incorporate the les-
sons of this research (e.g., State of Michigan, Governor’s Task Force, 2005). In ad-
dition to helping courts obtain more accurate testimony from young children, such
research-based conclusions illustrate how, at a broader level, knowledge of child
development can inform social policies.
In courtrooms such as this one, asking ques-
tions that will help children to testify accu-
rately is of the utmost importance.
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6 n chapTer 1 AN INTRODUCTION TO CHILD DEVELOPMENT
Understanding Human Nature
A third reason to study child development is to better understand human nature.
Many of the most intriguing questions regarding human nature concern children.
For example, does learning start only after children are born, or can it occur in the
womb? Can later upbringing in a loving home overcome the detrimental effects of
early rearing in a loveless institutional setting? Do children vary in personality and
intellect from the day they are born, or are they similar at birth, with differences
arising only because they have different experiences? Until recently, people could
only speculate about the answers to such questions. Now, however, developmental
scientists have methods that enable them to observe, describe, and
explain the process of development.
A particularly poignant illustration of the way in which scien-
tific research can increase understanding of human nature comes
from studies of how children’s ability to overcome the effects of
early maltreatment is affected by its timing, that is, the age at which
the maltreatment occurs. One such research program has examined
children whose early life was spent in horribly inadequate orphan-
ages in Romania in the late 1980s and early 1990s (McCall et al.,
2011; Nelson et al., 2007; Rutter et al., 2004). Children in these
orphanages had almost no contact with any caregiver. For reasons
that remain unknown, the brutal Communist dictatorship of that
era instructed staff workers not to interact with the children, even
when giving them their bottles. Staff members provided the infants
with so little physical contact that the crown of many infants’ heads
became flattened from the babies’ lying on their backs for 18 to 20
hours per day.
Shortly after the collapse of Communist rule in Romania, a number of these
children were adopted by families in Great Britain. When these children arrived in
Britain, most were severely malnourished, with more than half being in the low-
est 3% of children their age in terms of height, weight, and head circumference.
Most also showed varying degrees of mental retardation and were socially imma-
ture. The parents who adopted them knew of their deprived backgrounds and were
highly motivated to provide loving homes that would help the children overcome
the damaging effects of their early mistreatment.
To evaluate the long-term effects of their early deprivation, the physical, intel-
lectual, and social development of about 150 of the Romanian-born children was
examined at age 6 years. To provide a basis of comparison, the researchers also fol-
lowed the development of a group of British-born children who had been adopted
into British families before they were 6 months of age. Simply put, the question
was whether human nature is sufficiently flexible that the Romanian-born children
could overcome the extreme deprivation of their early experience, and if so, would
that flexibility decrease with the children’s age and the length of the deprivation.
By age 6, the physical development of the Romanian-born children had im-
proved considerably, both in absolute terms and in relation to the British-born
comparison group. However, the Romanian children’s early experience of depriva-
tion continued to influence their development, with the extent of negative effects
depending on how long the children had been institutionalized. Romanian-born
children who were adopted by British families before age 6 months, and who had
therefore spent the smallest portion of their early lives in the orphanages, weighed
about the same as British-born children when both were 6-year-olds. Romanian-
born children adopted between the ages of 6 and 24 months, and who therefore had
This infant is one of the children adopted
from a romanian orphanage in the 1990s.
how successfully he develops will depend
not only on the quality of caregiving he
receives in his adoptive home but also
on the amount of time he spent in the
orphanage and the age at which he was
adopted.
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spent more of their early lives in the orphanages, weighed less; and those adopted
between the ages of 24 and 42 months weighed even less (Rutter et al., 2004).
Intellectual development at age 6 years showed a similar pattern. The Romanian-
born children who had been adopted before age 6 months demonstrated levels of in-
tellectual competence comparable with those of the British-born group. Those who
had been adopted between ages 6 and 24 months did somewhat less well, and those
adopted between ages 24 and 42 months did even more poorly (Rutter et al., 2004).
The intellectual deficits of the Romanian children adopted after age 6 months were
just as great when the children were retested at age 11, indicating that the negative
effects of the early deprivation persisted over time (Beckett et al., 2006; Kreppner
et al., 2007).
The early experience in the orphanages had similar damaging effects on the
children’s social development (Kreppner et al., 2007; O’Connor, Rutter, & English
and Romanian Adoptees Study Team, 2000). Almost 20% of the Romanian-born
children who were adopted after age 6 months showed extremely abnormal social
behavior at age 6 years, not looking at their parents in anxiety-provoking situations
and willingly going off with strangers (versus 3% of the British-born comparison
group who did so). This atypical social development was accompanied by abnormal
brain activity. Brain scans obtained when the children were 8 years old showed that
those adopted after living for a substantial period in the orphanages had unusu-
ally low levels of neural activity in the amygdala, a brain area involved in emotional
reactions (Chugani et al., 2001). Subsequent studies have identified similar brain
abnormalities among children who spent their early lives in poor-quality orphan-
ages in Russia and East Asia as well (Nelson et al., 2011; Tottenham et al., 2010).
These findings reflect a basic principle of child development that is relevant to
many aspects of human nature: The timing of experiences influences their effects. In the
present case, children were sufficiently flexible to overcome the effects of living in the
loveless, unstimulating institutions if the deprivation ended relatively early; living in
the institutions until older ages, however, had effects that were rarely overcome, even
when children spent subsequent years in loving and stimulating environments. The
adoptive families clearly made a huge positive difference in their children’s lives, but
the later the age of adoption, the greater the long-term effects of early deprivation.
review:
There are at least three good reasons to learn about child development: to improve one’s own
child-rearing, to help society promote the well-being of children in general, and to better un-
derstand human nature.
Historical Foundations of the Study
of Child Development
From ancient Greece to the early years of the twentieth century, a number of pro-
found thinkers observed and wrote about children. Their goals were like those
of contemporary researchers: to help people become better parents, to improve
children’s well-being, and to understand human nature. Unlike contemporary
researchers, they usually based their conclusions on general philosophical beliefs
and informal observations of a few children. Still, the issues they raised are suf-
ficiently important, and their insights sufficiently deep, that their views continue
to be of interest.

8 n chapTer 1 AN INTRODUCTION TO CHILD DEVELOPMENT
Early Philosophers’ Views of Children’s Development
Some of the earliest recorded ideas about children’s development were those of
Plato and Aristotle. These classic Greek philosophers, who lived in the fourth cen-
tury b.c.e., were particularly interested in how children’s development is influenced
by their nature and by the nurture they receive.
Both Plato and Aristotle believed that the long-term welfare of society de-
pended on the proper raising of children. Careful upbringing was essential because
children’s basic nature would otherwise lead to their becoming rebellious and un-
ruly. Plato viewed the rearing of boys as a particularly demanding challenge for
parents and teachers:
Now of all wild things, a boy is the most difficult to handle. Just because he more
than any other has a fount of intelligence in him which has not yet “run clear,” he is
the craftiest, most mischievous, and unruliest of brutes.
(Laws, bk. 7, p. 808)
Consistent with this view, Plato emphasized self-control and discipline as the most
important goals of education (Borstelmann, 1983).
Aristotle agreed with Plato that discipline was necessary, but he was more
concerned with fitting child-rearing to the needs of the individual child. In his
words:
It would seem . . . that a study of individual character is the best way of making edu-
cation perfect, for then each [child] has a better chance of receiving the treatment
that suits him.
(Nicomachean Ethics, bk. 10, chap. 9, p. 1180)
Plato and Aristotle differed more profoundly in their views of how children acquire
knowledge. Plato believed that children have innate knowledge. For example, he
believed that children are born with a concept of “animal” that, from birth onward,
automatically allows them to recognize that the dogs, cats, and other creatures they
encounter are animals. In contrast, Aristotle believed that all knowledge comes
from experience and that the mind of an infant is like a blackboard on which noth-
ing has yet been written.
Roughly 2000 years later, the English philosopher John Locke (1632–1704) and
the French philosopher Jean-Jacques Rousseau (1712–1778) refocused attention
on the question of how parents and society in general can best promote children’s
development. Locke, like Aristotle, viewed the child as a tabula rasa, or blank slate,
whose development largely reflects the nurture provided by the child’s parents and
the broader society. He believed that the most important goal of child-rearing is
the growth of character. To build children’s character, parents need to set good ex-
amples of honesty, stability, and gentleness. They also need to avoid indulging the
child, especially early in life. However, once discipline and reason have been in-
stilled, Locke believed,
authority should be relaxed as fast as their age, discretion, and good behavior could
allow it. . . . The sooner you treat him as a man, the sooner he will begin to be one.
(Cited in Borstelmann, 1983, p. 20)
In contrast to Locke’s advocating discipline before freedom, Rousseau believed
that parents and society should give children maximum freedom from the begin-
ning. Rousseau claimed that children learn primarily from their own spontaneous
interactions with objects and other people, rather than through instruction by par-
ents or teachers. He even argued that children should not receive any formal edu-
cation until about age 12, when they reach “the age of reason” and can judge for

H I S T O R I C A L F O U N D A T I O N S O F T H E S T U D Y O F C H I L D D E V E L O P M E N T n 9
themselves the worth of what they are told. Before then, they should be allowed the
freedom to explore whatever interests them.
Although formulated long ago, these and other philosophical positions continue
to underlie many contemporary debates, including whether children should receive
direct instruction in desired skills and knowledge or be given maximum freedom
to discover the skills and knowledge for themselves, and whether parents should
build their children’s character through explicit instruction or through the implicit
guidance provided by the parents’ own behavior.
Social Reform Movements
Another precursor of the contemporary field of child psychology was early social
reform movements that were devoted to improving children’s lives by changing the
conditions in which they lived. During the Industrial Revolution of the eighteenth
and nineteenth centuries, a great many children in Europe and the United States
worked as poorly paid laborers with no legal protections. Some were as young as 5
and 6 years; many worked up to 12 hours a day in factories or mines, often in ex-
tremely hazardous circumstances. These harsh conditions worried a number of so-
cial reformers, who began to study how such circumstances affected the children’s
development. For example, in a speech before the British House of Commons in
1843, the Earl of Shaftesbury noted that the narrow tunnels where children dug
out coal had
very insufficient drainage [and] are so low that only little
boys can work in them, which they do naked, and often
in mud and water, dragging sledge-tubs by the girdle and
chain. . . . Children of amiable temper and conduct, at 7
years of age, often return next season from the collieries
greatly corrupted . . . with most hellish dispositions.
(Quoted in Kessen, 1965, pp. 46–50)
The Earl of Shaftesbury’s effort at social reform
brought partial success—a law forbidding employment
of girls and of boys younger than 10. In addition to bring-
ing about the first child labor laws, this and other early
social reform movements established a legacy of research
conducted for the benefit of children and provided some
of the earliest recorded descriptions of the adverse effects
that harsh environments can have on children.
Darwin’s Theory of Evolution
Later in the nineteenth century, Charles Darwin’s work on evolution inspired a
number of scientists to propose that intensive study of children’s development
might lead to important insights into human nature. Darwin himself was in-
terested in child development and in 1877 published an article entitled “A Bio-
graphical Sketch of an Infant,” which presented his careful observations of the
motor, sensory, and emotional growth of his infant son, William. Darwin’s “baby
biography”—a systematic description of William’s day-to-day development—
represented one of the first methods for studying children.
Such intensive studies of individual children’s growth continue to be a distinc-
tive feature of the modern field of child development. Darwin’s evolutionary theory
also continues to influence the thinking of modern developmentalists on a wide
During the eighteenth, nineteenth, and early
twentieth centuries, many young children
worked in coal mines and factories. Their
hours were long, and the work was often
unhealthy and dangerous. concern over the
well-being of such children led to some of
the earliest research on child development.
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range of topics: infants’ attachment to their mothers (Bowlby, 1969), innate fear of
natural dangers such as spiders and snakes (Rakison & Derringer, 2008), sex differ-
ences (Geary, 2009), aggression and altruism (Tooby & Cosmides, 2005), and the
mechanisms underlying learning (Siegler, 1996).
The Beginnings of Research-Based Theories
of Child Development
At the end of the nineteenth century and the beginning of the twentieth, the first
theories of child development that incorporated research findings were formulated.
One prominent theory, that of the Austrian psychiatrist Sigmund Freud, was based
in large part on his patients’ recollections of their dreams and childhood experi-
ences. Freud’s psychoanalytic theory proposed that biological drives, especially sexual
ones, are a crucial influence on development.
Another prominent theory of the same era, that of American psychologist John
Watson, was based primarily on the results of experiments that examined learning
in animals and children. Watson’s behaviorist theory argued that children’s develop-
ment is determined by environmental factors, especially the rewards and punish-
ments that follow the children’s actions.
By current standards, the research methods on which these theories were based
were crude. Nonetheless, these early scientific theories were better grounded in re-
search evidence than were their predecessors, and, as you will see later in the chap-
ter, they inspired more sophisticated ideas about the processes of development and
more rigorous research methods for studying how development occurs.
review:
Philosophers such as Plato, Aristotle, Locke, and Rousseau, as well as early scientific theorists
such as Darwin, Freud, and Watson, raised many of the deepest issues about child develop-
ment. These issues included how nature and nurture influence development, how best to raise
children, and how knowledge of children’s development can be used to advance their welfare.
Enduring Themes in Child Development
The modern study of child development begins with a set of fundamental ques-
tions. Everything else—theories, concepts, research methods, data, and so on—is
part of the effort to answer these questions. Although experts in the field might
choose different particular questions as the most important, there is widespread
agreement that the seven questions in Table 1.1 are among the most important.
These questions form a set of themes that we will highlight throughout the book
as we examine specific aspects of child development. In this section, we introduce
and briefly discuss each question and the theme that corresponds to it.
1 Nature and Nurture: How Do Nature and Nurture
Together Shape Development?
The most basic question about child development is how nature and nurture in-
teract to shape the developmental process. Nature refers to our biological endow-
ment, in particular, the genes we receive from our parents. This genetic inheritance
TABLE 1.1
Basic Questions about
child Development
1. How do nature and nurture together
shape development? (Nature and nurture)
2. How do children shape their own
development? (The active child)
3. In what ways is development continuous,
and in what ways is it discontinuous?
(Continuity/discontinuity)
4. How does change occur? (Mechanisms of
development)
5. How does the sociocultural context
influence development? (The
sociocultural context)
6. How do children become so different
from one another? (Individual
differences)
7. How can research promote children’s
well-being? (Research and children’s
welfare)
nature n our biological endowment; the
genes we receive from our parents

E N D U R I N G T H E M E S I N C H I L D D E V E L O P M E N T n 11
influences every aspect of our make-up, from broad characteristics such as physical
appearance, personality, intellect, and mental health to specific preferences, such
as political attitudes and propensity for thrill-seeking (Plomin, 2004; Rothbart &
Bates, 2006). Nurture refers to the wide range of environments, both physical and
social, that influence our development, including the womb in which we spend the
prenatal period, the homes in which we grow up, the schools that we attend, the
broader communities in which we live, and the many people with whom we interact.
Popular depictions often present the nature–nurture question as an either/or
proposition: “What determines how a person develops, heredity or environment?”
However, this either/or phrasing is deeply misleading. All human characteristics—
our intellect, our personality, our physical appearance, our emotions—are created
through the joint workings of nature and nurture, that is, through the constant
interaction of our genes and our environment. Accordingly, rather than asking
whether nature or nurture is more important, developmentalists ask how nature and
nurture work together to shape development.
That this is the right question to ask is vividly illustrated by findings on the
development of schizophrenia. Schizophrenia is a serious mental illness, often
characterized by hallucinations, delusions, confusion, and irrational behavior.
There is obviously a genetic component to this disease. Children who have a
schizophrenic parent have a much higher probability than other children of de-
veloping the illness later in life, even when they are adopted as infants and there-
fore are not exposed to their parents’ schizophrenic behavior (Kety et al., 1994).
Among identical twins—that is, twins whose genes are identical—if one twin has
schizophrenia, the other has a roughly 50% chance of also having schizophrenia,
as opposed to the roughly 1% probability for the general population (Gottesman,
1991; Cardno & Gottesman, 2000; see Figure 1.1). At the same time, the envi-
ronment is also clearly influential, since roughly 50% of children who have an
identical twin with schizophrenia do not become schizophrenic themselves, and
children who grow up in troubled homes are more likely to become schizophrenic
than are children raised in a normal household. Most important, however, is
the interaction of genes and environment. A study of adopted children, some of
whose biological parents were schizophrenic, indicated that the only children
who had any substantial likelihood of becoming schizophrenic were those who
had a schizophrenic parent and who also were adopted into a troubled family
(Tienari, Wahlberg, & Wynne, 2006).
A remarkable recent series of studies has revealed
some of the biological mechanisms through which na-
ture and nurture interact. These studies show that just
as the genome—each person’s complete set of hered-
itary information—influences behaviors and experi-
ences, behaviors and experiences influence the genome
(Cole, 2009; Meaney, 2010). This might seem im-
possible, given the well-known fact that each person’s
DNA is constant throughout life. However, the ge-
nome includes not only DNA but also proteins that
regulate gene expression by turning gene activity on
and off. These proteins change in response to experi-
ence and, without structurally altering DNA, can re-
sult in enduring changes in cognition, emotion, and
behavior. This discovery has given rise to a new field
called epigenetics, the study of stable changes in gene
T
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could appropriate nurture have allowed
the Three Stooges to become upper-class
gentlemen?
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Relation to schizophrenic patient
FIGURE 1.1 Genetic relatedness and
schizophrenia The closer the biological
relation, the stronger the probability that
relatives of a person with schizophrenia
will have the same mental illness. (after
Gottes man, 1991)
nurture n the environments, both
physical and social, that influence our
development
genome n each person’s complete set of
hereditary information
epigenetics n the study of stable
changes in gene expression that are medi-
ated by the environment

12 n chapTer 1 AN INTRODUCTION TO CHILD DEVELOPMENT
expression that are mediated by the environment. Stated simply, epigenetics exam-
ines how experience gets under the skin.
Evidence for the enduring epigenetic impact of early experiences and behav-
iors comes from research on methylation, a biochemical process that reduces ex-
pression of a variety of genes and that is involved in regulating reactions to stress
(Champagne & Curley, 2009; Meaney, 2001). One recent study showed that the
amount of stress that mothers reported experiencing during their children’s infancy
was related to the amount of methylation in the children’s genomes 15 years later
(Essex et al., 2013). Other studies showed increased methylation in the cord-blood
DNA of newborns of depressed mothers (Oberlander et al., 2008) and in adults who
were abused as children (McGowan et al., 2009), leading researchers to speculate that
such children are at heightened risk for depression as adults (Rutten & Mill, 2009).
As these examples illustrate, developmental outcomes emerge from the constant
bidirectional interaction of nature and nurture. To say that one is more important
than the other, or even that the two are equally important, drastically oversimplifies
the developmental process.
2 The Active Child: How Do Children Shape
Their Own Development?
With all the attention that is paid to heredity and environment, many people over-
look the ways in which children’s own actions contribute to their development.
Even in infancy and early childhood, this contribution can be seen in a multitude
of areas, including attention, language use, and play.
Children first begin to shape their own development through their selection of
what to pay attention to. Even newborns prefer to look at things that move and
make sounds. This preference helps them learn about important parts of the world,
such as people, other animals, and inanimate moving objects. When looking at peo-
ple, infants’ attention is particularly drawn to faces, especially their mother’s face:
Given a choice of looking at a stranger’s face or their mother’s, even 1-month-olds
choose to look at Mom (Bartrip, Morton, & de Schonen, 2001). At first, infants’
attention to their mother’s face is not accompanied by any visible emotion, but by
the end of the 2nd month, infants smile and coo more when focusing intently on
their mother’s face than at other times. This smiling and cooing by the infant elic-
its smiling and talking by the mother, which elicits further cooing and smiling by
the infant, and so on (Lavelli & Fogel, 2005). In this way, infants’ preference for
attending to their mother’s face leads to social interactions that can strengthen the
mother–infant bond.
Once children begin to speak, usually between 9 and 15 months of age, their
contribution to their own development becomes more evident. For example, tod-
dlers (1- and 2-year-olds) often talk when they are alone in a room. Only if chil-
dren were internally motivated to learn language would they practice talking when
no one was present to react to what they are saying. Many parents are startled when
they hear this “crib speech” and wonder if something is wrong with a baby who
would engage in such odd-seeming behavior. However, the activity is entirely nor-
mal, and the practice probably helps toddlers improve their speech.
Young children’s play provides many other examples of how their internally mo-
tivated activity contributes to their development. Children play by themselves for
the sheer joy of doing so, but they also learn a great deal in the process. Anyone
who has seen a baby bang a spoon against the tray of a high chair or intentionally
drop food on the floor would agree that, for the baby, the activity is its own reward.
©
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One of the earliest ways children shape their
own development is through their choice of
where to look. From the first month of life,
seeing Mom is a high priority.
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play contributes to children’s development
in many ways, including the spatial under-
standing and attention to detail required to
complete puzzles.
methylation n A biochemical process
that influences behavior by suppressing
gene activity and expression

E N D U R I N G T H E M E S I N C H I L D D E V E L O P M E N T n 13
At the same time, the baby is learning about the
noises made by colliding objects, about the speed
at which objects fall, and about the limits of his or
her parents’ patience.
Young children’s fantasy play seems to make an
especially large contribution to their knowledge of
themselves and other people. Starting at around
age 2 years, children sometimes pretend to be dif-
ferent people in make-believe dramas. For ex-
ample, they may pretend to be superheroes doing
battle with monsters or play the role of parents
taking care of babies. In addition to being inher-
ently enjoyable, such play appears to teach chil-
dren valuable lessons, including how to cope with
fears and how to interact with others (Howes &
Matheson, 1992; Smith, 2003). Older children’s
play, which typically is more organized and rule-
bound, teaches them additional valuable lessons,
such as the self-control needed for turn-taking, adhering to rules, and controlling
one’s emotions in the face of setbacks (Hirsch-Pasek et al., 2008). As we discuss
later in the chapter, children’s contributions to their own development strengthen
and broaden as they grow older and become increasingly able to choose and shape
their environments.
3 Continuity/Discontinuity: In What Ways Is
Development Continuous, and in What Ways
Is It Discontinuous?
Some scientists envision children’s development as a continuous process of small
changes, like that of a pine tree growing taller and taller. Others see the process as
a series of sudden, discontinuous changes, like the transition from caterpillar to
cocoon to butterfly (Figure 1.2). The debate over which of these views is more ac-
curate has continued for decades.
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adolescents who participate in sports and
other extracurricular activities are more
likely to complete high school, and less
likely to get into trouble, than peers who
are not engaged in these activities. This is
another example of how children contribute
to their own development.
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Chrysalis
(in cocoon)
Butterfly
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Pine tree: Developmental continuity Butterfly: Developmental discontinuity
(a) (b)
FIGURE 1.2 continuous and discon-
tinuous development Some researchers
see development as a continuous, gradual
process, akin to a tree’s growing taller with
each passing year. Others see it as a discon-
tinuous process, involving sudden dramatic
changes, such as the transition from cater-
pillar to cocoon to butterfly. each view fits
some aspects of child development.
continuous development n the idea
that changes with age occur gradually, in
small increments, like that of a pine tree
growing taller and taller
discontinuous development n the
idea that changes with age include occa-
sional large shifts, like the transition from
caterpillar to cocoon to butterfly

14 n chapTer 1 AN INTRODUCTION TO CHILD DEVELOPMENT
Researchers who view development as discontinuous start from a common ob-
servation: children of different ages seem qualitatively different. A 4-year-old and
a 6-year-old, for example, seem to differ not only in how much they know but in
the whole way they think about the world. To appreciate these differences, consider
two conversations between Beth, the daughter of one of the authors, and Beth’s
mother. The first conversation took place when Beth was 4 years old, the second,
when she was 6. Both conversations occurred after Beth had watched her mother
pour all the water from a typical drinking glass into a taller, narrower glass. Here is
the conversation that occurred when Beth was 4:
Mother: Is there still the same amount of water?
Beth: No.
Mother: Was there more water before, or is there more now?
Beth: There’s more now.
Mother: What makes you think so?
Beth: The water is higher; you can see it’s more.
Mother: Now I’ll pour the water back into the regular glass. Is there the same
amount of water as when the water was in the same glass before?
Beth: Yes.
Mother: Now I’ll pour all the water again into the tall thin glass. Does the
amount of water stay the same?
Beth: No, I already told you, there’s more water when it’s in the tall glass.
Two years later, Beth responded to the same problem quite differently:
Mother: Is there still the same amount of water?
Beth: Of course!
What accounts for this change in Beth’s thinking? Her everyday observations
of liquids being poured cannot have been the reason for it; Beth had seen liquids
poured on a great number of occasions before she was 4, yet failed to develop the
understanding that the volume remains constant. Experience with the specific
task could not explain the change either, because Beth had no further exposure
to the task between the first and second conversation. Then why, as a 4-year-old,
would Beth be so confident that pouring the water into the taller, narrower glass
increased the amount and, as a 6-year-old, be so confident that it did not?
This conservation-of-liquid-quantity problem is actually a classic technique de-
signed to test children’s level of thinking. It has been used with thousands of chil-
dren around the world, and virtually all the children studied, no matter what their
culture, have shown the same type of change in reasoning as Beth did (though
usually at somewhat older ages). Furthermore, such age-related differences in
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children’s behavior on piaget’s conser-
vation-of-liquid-quanity problem is often
used to exemplify the idea that develop-
ment is discontinuous. The child first sees
equal amounts of liquid in similarly shaped
glasses and an empty, differently shaped
glass. Then, the child sees the liquid from
one glass poured into the differently shaped
glass. Finally, the child is asked whether
the amount of liquid remains the same or
whether one glass has more. Young children,
like this girl, are unshakable in their belief
that the glass with the taller liquid column
has more liquid. a year or two later, they are
equally unshakable in their belief that the
amount of liquid in each glass is the same.

E N D U R I N G T H E M E S I N C H I L D D E V E L O P M E N T n 15
understanding pervade children’s thinking. Consider two letters to Mr. Rogers,
one sent by a 4-year-old and one by a 5-year-old (Rogers, 1996, pp. 10–11):
Dear Mr. Rogers,
I would like to know how you get in the TV.
(Robby, age 4)
Dear Mr. Rogers,
I wish you accidentally stepped out of the TV into my house so I could play with you.
( Josiah, age 5)
Clearly, these are not ideas that an older child would entertain. As with Beth’s
case, we have to ask, “What is it about 4- and 5-year-olds that leads them to form
such improbable beliefs, and what changes occur that makes such notions laugh-
able to 6- and 7-year-olds?”
One common approach to answering these questions comes from stage
theories, which propose that development occurs in a progression of distinct age-
related stages, much like the butterfly example in Figure 1.2b. According to these
theories, a child’s entry into a new stage involves relatively sudden, qualitative
changes that affect the child’s thinking or behavior in broadly unified ways and
move the child from one coherent way of experiencing the world to a different co-
herent way of experiencing it.
Among the best-known stage theories is Jean Piaget’s theory of cognitive
development, the development of thinking and reasoning. This theory holds that
between birth and adolescence, children go through four stages of cognitive growth,
each characterized by distinct intellectual abilities and ways of understanding the
world. For example, according to Piaget’s theory, 2- to 5-year-olds are in a stage of
development in which they can focus on only one aspect of an event, or one type
of information, at a time. By age 7, children enter a different stage, in which they
can simultaneously focus on and coordinate two or more aspects of an event and
can do so on many different tasks. According to this view, when confronted with a
problem like the one that Beth’s mother presented to her, most 4- and 5-year-olds
focus on the single dimension of height, and therefore perceive the taller, narrower
glass as having more water. In contrast, most 7- and 8-year-olds consider both rel-
evant dimensions of the problem simultaneously. This allows them to realize that
although the column of water in the taller glass is higher, the column also is nar-
rower, and the two differences offset each other.
In the course of reading this book, you will encounter a number of other stage
theories, including Sigmund Freud’s theory of psychosexual development, Erik
Erikson’s theory of psychosocial development, and Lawrence Kohlberg’s theory of
moral development. Each of these stage theories proposes that children of a given
age show broad similarities across many situations and that children of different
ages tend to behave very differently.
Such stage theories have been very influential. In the past 20 years, however,
many researchers have concluded that most developmental changes are gradual
rather than sudden, and that development occurs skill by skill, task by task, rather
than in a broadly unified way (Courage & Howe, 2002; Elman et al., 1996; Thelen
& Smith, 2006). This view of development is less dramatic than that of stage theo-
ries, but a great deal of evidence supports it. One such piece of evidence is the fact
that a child often will behave in accord with one proposed stage on some tasks but
in accord with a different proposed stage on other tasks (Fischer & Bidell, 2006).
This variable level of reasoning makes it difficult to view the child as being “in”
either stage.
stage theories n approaches that pro-
pose that development involves a series of
discontinuous, age-related phases
cognitive development n the develop-
ment of thinking and reasoning

16 n chapTer 1 AN INTRODUCTION TO CHILD DEVELOPMENT
Much of the difficulty in deciding whether de-
velopment is continuous or discontinuous is that the
same facts can look very different, depending on one’s
perspective. Consider the seemingly simple question
of whether children’s height increases continuously
or discontinuously. Figure 1.3a shows a boy’s height,
measured yearly from birth to age 18 (Tanner, 1961).
When one looks at the boy’s height at each age, devel-
opment seems smooth and continuous, with growth
occurring rapidly early in life and then slowing down.
However, when you look at Figure 1.3b, a different
picture emerges. This graph illustrates the same boy’s
growth, but it depicts the amount of growth from one
year to the next. The boy grew every year, but he grew
most during two periods: from birth to age 2½, and
from ages 13 to 15. These are the kinds of data that
lead people to talk about discontinuous growth and
about a separate stage of adolescence that includes a
physical growth spurt.
So, is development fundamentally continuous or
fundamentally discontinuous? The most reasonable
answer seems to be, “It depends on how you look at it
and how often you look.” Imagine the difference be-
tween the perspective of an uncle who sees his niece
every 2 or 3 years and that of the niece’s parents, who
see her every day. The uncle will almost always be
struck with the huge changes in his niece since he last
saw her. The niece will be so different that it will seem
that she has progressed to a higher stage of develop-
ment. In contrast, the parents will most often be struck
by the continuity of her development; to them, she usually will just seem to grow up
a bit each day. Throughout this book, we will be considering the changes, large and
small, sudden and gradual, that have led some researchers to emphasize the conti-
nuities in development and others to emphasize the discontinuities.
4 Mechanisms of Development: How Does
Change Occur?
Perhaps the deepest mystery about children’s development is expressed by the ques-
tion “How does change occur?” In other words, what are the mechanisms that
produce the remarkable changes that children undergo with age and experience?
A very general answer was implicit in the earlier discussion of the theme of nature
and nurture. The interaction of genome and environment determines both what
changes occur and when those changes occur. The challenge comes in specifying
more precisely how any given change occurs.
One particularly interesting analysis of the mechanisms of developmental change
involves the roles of brain activity, genes, and learning experiences in the development
of effortful attention (e.g., Rothbart, Sheese, & Posner, 2007). Effortful attention in-
volves voluntary control of one’s emotions and thoughts. It includes processes such as
inhibiting impulses (e.g., obeying requests to put all of one’s toys away, as opposed to
putting some away but then getting distracted and playing with the remaining ones);
22
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FIGURE 1.3 continuous and discon-
tinuous growth Depending on how it is
viewed, changes in height can be viewed
as either continuous or discontinuous. (a)
examining a boy’s height in absolute terms
from birth to 18 years makes the growth
look gradual and continuous (from Tanner,
1961). (b) examining the increases in the
same boy’s height from one year to the next
over the same period shows rapid growth
during the first 2½ years, then slower
growth, then a growth spurt in adolescence,
then a rapid decrease in growth; viewed this
way, growth seems discontinuous.

E N D U R I N G T H E M E S I N C H I L D D E V E L O P M E N T n 17
controlling emotions (e.g., not crying when failing to get one’s way); and focus-
ing attention (e.g., concentrating on one’s homework despite the inviting sounds of
other children playing outside). Difficulty in exerting effortful attention is associated
with behavioral problems, weak math and reading skills, and mental illness (Blair &
Razza, 2007; Diamond & Lee, 2011; Rothbart & Bates, 2006).
Studies of the brain activity of people performing tasks that require control of
thoughts and emotions show that connections are especially active between the
anterior cingulate, a brain structure involved in setting and attending to goals, and
the limbic area, a part of the brain that plays a large role in emotional reactions
(Etkin et al., 2006). Connections between brain areas such as the anterior cingulate
and the limbic area develop considerably during childhood, and their development
appears to be one mechanism that underlies improving effortful attention during
childhood (Rothbart et al., 2007).
What role do genes and learning experiences play in influencing this mech-
anism of effortful attention? Specific genes influence the production of key
neuro transmitters—chemicals involved in communication among brain cells.
Variations among children in these genes are associated with variations in the
quality of performance on tasks that require effortful attention (Canli et al., 2005;
Diamond et al., 2004; Rueda et al., 2005). These genetic influences do not occur
in a vacuum, however. As noted in the discussion of epigenetics, the environment
plays a crucial role in the expression of genes. Infants with a particular form of
one of the genes in question show differences in effortful attention related to the
quality of parenting they receive, with lower-quality parenting being associated
with lower ability to regulate attention (Sheese et al., 2007). Among children
who do not have that form of the gene, quality of parenting has less effect on ef-
fortful attention.
Children’s experiences also can change the wiring of the brain system that pro-
duces effortful attention. Rueda and colleagues (2005) presented 6-year-olds with
a 5-day training program that used computerized exercises to improve capacity
for effortful attention. Examination of electrical activity in the anterior cingulate
indicated that those 6-year-olds who had completed the computerized exercises
showed improved effortful attention. These children also showed improved perfor-
mance on intelligence tests, which makes sense given the sustained effortful atten-
tion required by such tests. Thus, the experiences that children encounter influence
their brain processes and gene expression, just as brain processes and genes influ-
ence children’s reactions to experiences. More generally, a full understanding of the
mechanisms that produce developmental change requires specifying how genes,
brain structures and processes, and experiences interact.
5 The Sociocultural Context: How Does the
Sociocultural Context Influence Development?
Children grow up in a particular set of physical and social environments, in a par-
ticular culture, under particular economic circumstances, at a particular time in
history. Together, these physical, social, cultural, economic, and historical circum-
stances interact to constitute the sociocultural context of a child’s life. This socio-
cultural context influences every aspect of children’s development.
A classic depiction of the components of the sociocultural context is Urie
Bronfenbrenner’s (1979) bioecological model (discussed in depth in Chapter 9).
The most obviously important component of children’s sociocultural contexts is the
people with whom they interact—parents, grandparents, brothers, sisters, day-care
neurotransmitters n chemicals
involved in communication among brain
cells
sociocultural context n the physical,
social, cultural, economic, and historical
circumstances that make up any child’s
environment

18 n chapTer 1 AN INTRODUCTION TO CHILD DEVELOPMENT
providers, teachers, friends, classmates, and so on—and the physical environment
in which they live—their house, day-care center, school, neighborhood, and so on.
Another important but less tangible component of the sociocultural context is the
institutions that influence children’s lives: educational systems, religious institu-
tions, sports leagues, social organizations (such as boys’ and girls’ clubs), and so on.
Yet another important set of influences are the general characteristics of the
child’s society: its economic and technological advancement; its values, attitudes,
beliefs, and traditions; its laws and political structure; and so on. For example, the
simple fact that most toddlers and preschoolers growing up in the United States
today go to child care outside their homes reflects a number of these less tangible
sociocultural factors, including:
1. The historical era (50 years ago, far fewer children in the United States
attended child-care centers)
2. The economic structure (there are far more opportunities today for women
with young children to work outside the home)
3. Cultural beliefs (for example, that receiving child care outside the home does
not harm children)
4. Cultural values (for example, the value that mothers of young children should
be able to work outside the home if they wish).
Attendance at child-care centers, in turn, partly determines the people children
meet and the activities in which they engage.
One method that developmentalists use to understand the influence of the so-
ciocultural context is to compare the lives of children who grow up in different
cultures. Such cross-cultural comparisons often reveal that practices that are rare or
nonexistent in one’s own culture are common in other cultures. The following com-
parison of young children’s sleeping arrangements in different societies illustrates
the value of such cross-cultural research.
In most families in the United States, newborn infants sleep in their parents’
bedroom, either in a crib or in the same bed. However, when infants are 2 to 6
months old, parents usually move them to another bedroom where they sleep alone
(Greenfield, Suzuki, & Rothstein-Fisch, 2006). This seems natural to most people
raised in the United States, because it is how we and others whom we know were
raised. From a worldwide perspective, however, such sleep-
ing arrangements are highly unusual. In most other societies,
including economically advanced nations such as Italy, Japan,
and South Korea, babies almost always sleep in the same bed as
their mother for the first few years, and somewhat older chil-
dren also sleep in the same room as their mother, sometimes in
the same bed (e.g., Nelson, Schiefenhoevel, & Haimerl, 2000;
Whiting & Edwards, 1988). Where does this leave the fa-
ther? In some cultures, the father sleeps in the same bed with
mother and baby; in others, he sleeps in a separate bed or in a
different room.
How do these differences in sleeping arrangements af-
fect children? To find out, researchers interviewed mothers in
middle-class U.S. families in Salt Lake City, Utah, and in rural
Mayan families in Guatemala (Morelli et al., 1992). These in-
terviews revealed that by age 6 months, the large majority of
the U.S. children had begun sleeping in their own bedroom. As
the children grew out of infancy, the nightly separation of child OW
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In many countries, including Denmark,
the country in which this mother and child
live, mothers and children sleep together
for the first several years of the child’s life.
This sociocultural pattern is in sharp con-
trast to the U.S. practice of having infants
sleep separately from their parents soon
after birth.

E N D U R I N G T H E M E S I N C H I L D D E V E L O P M E N T n 19
and parents became a complex ritual, surrounded by activities intended to comfort
the child, such as telling stories, reading children’s books, singing songs, and so on.
About half the children were reported as taking a comfort object, such as a blanket
or teddy bear, to bed with them.
In contrast, interviews with the Mayan mothers indicated that their children
typically slept in the same bed with them until the age of 2 or 3 years and continued
to sleep in the same room with them for years thereafter. The children usually went
to sleep at the same time as their parents. None of the Mayan parents reported bed-
time rituals, and almost none reported their children taking comfort objects, such
as dolls or stuffed animals, to bed with them.
Why do sleeping arrangements differ across cultures? Interviews with the Mayan
and U.S. parents indicated that the crucial consideration for them in determining
sleeping arrangements was cultural values. Mayan culture prizes interdependence
among people. The Mayan parents expressed the belief that having a young child
sleep with the mother is important for developing a good parent–child relationship,
for avoiding the child’s becoming distressed at being alone, and for helping parents
spot any problems the child is having. They often expressed shock and pity when
told that infants in the United States typically sleep separately from their parents
(Greenfield et al., 2006). In contrast, U.S. culture prizes independence and self-
reliance, and the U.S. mothers expressed the belief that having babies and young
children sleep alone promotes these values, as well as allowing intimacy between
husbands and wives (Morelli et al., 1992). These differences illustrate both how
practices that strike us as natural may differ greatly across cultures and how the
simple conventions of everyday life often reflect deeper values.
Contexts of development differ not just between cultures but also within them.
In modern multicultural societies, many contextual differences are related to eth-
nicity, race, and socioeconomic status (SES)—a measure of social class that is
based on income and education. Virtually all aspects of children’s lives—from the
food they eat to the parental discipline they receive to the games they play—vary
with ethnicity, race, and SES.
The socioeconomic context exerts a particularly large influence on children’s
lives. In economically advanced societies, including the United States, most chil-
dren grow up in comfortable circumstances, but millions of other children do not.
In 2011, about 19% of U.S. families with children had incomes below the poverty
line (in that year, $18,530 for a family of three with one adult and two children). In
absolute numbers, that translates into about 16 million children growing up in pov-
erty (U.S. Census Bureau, 2012). As shown in Table 1.2, poverty rates are especially
high in Black and Hispanic families and in families of all races that are headed by
single mothers. Poverty rates are also very high among the roughly 25% of children
in the United States who are either immigrants or the children of immigrants—
roughly twice as high as among children of native-born parents (Hernandez,
Denton, & Macartney, 2008; Smeeding, 2008).
Children from poor families tend to do less well than other children in many ways
(G. W. Evans et al., 2005; Morales & Guerra, 2006). In infancy, they are more likely
to have serious health problems. In childhood, they are more likely to have social/
emotional and behavioral problems. Throughout childhood and adolescence, they
tend to have smaller vocabularies, lower IQs, and lower math and reading scores on
standardized achievement tests. In adolescence, they are more likely to have a baby
or drop out of school (G. W. Evans et al., 2005; Luthar, 1999; McLoyd, 1998).
These negative outcomes are not surprising when we consider the huge array
of disadvantages that poor children face. Compared with children who grow up in
TABLE 1.2
percentages of U.S. Families with
children Younger than 18 Living
Below poverty Line in 2011
Group % in
Poverty
Overall U.S. Population 19
White, non-Hispanic 12
Black 33
Hispanic 29
Asian 12
Married Couples 9
White, non-Hispanic 5
Black 12
Hispanic 20
Asian 9
Single Parent: Female Head of
Household
41
White, non-Hispanic 33
Black 47
Hispanic 49
Asian 26
Source: U.S. Census Bureau, 2012
socioeconomic status (SES) n a mea-
sure of social class based on income and
education

20 n chapTer 1 AN INTRODUCTION TO CHILD DEVELOPMENT
more affluent circumstances, they are more likely to live in dangerous neighbor-
hoods, to attend inferior day-care centers and schools, and to be exposed to high
levels of air and water pollution (Dilworth-Bart & Moore, 2006; G. W. Evans,
2004). In addition, their parents read to them less, talk to them less, provide fewer
books in the home, and are less involved in their schooling. Poor children also are
more likely than affluent children to grow up in single-parent homes or to be raised
by neither biological parent. The accumulation of these disadvantages, rather than
any single one of them, seems to be the greatest obstacle to poor children’s success-
ful development (Luthar, 2006; Morales & Guerra, 2006).
And yet as we saw in Werner’s study of the children of Kauai, described at the
beginning of the chapter, many children do overcome the obstacles that poverty
presents. Such resilient children tend to have three characteristics: (1) positive per-
sonal qualities, such as high intelligence, an easygoing personality, and an optimis-
tic outlook on the future; (2) a close relationship with at least one parent; and (3) a
close relationship with at least one adult other than their parents, such as a grand-
parent, teacher, coach, or family friend (Chen & Miller, 2012; Masten, 2007). Thus,
although poverty poses serious obstacles to successful development, many children
do surmount the challenges—usually with the help of adults in their lives.
6 Individual Differences: How Do Children Become So
Different from One Another?
Anyone who has experience with children is struck by their uniqueness—their dif-
ferences not only in physical appearance but in everything from activity level and
temperament to intelligence, persistence, and emotionality. These differences among
children emerge quickly. Some infants in their first year are shy, others outgoing.
Some infants play with or look at objects for prolonged periods; others rapidly shift
from activity to activity. Even children in the same family often differ substantially,
as you probably already know if you have siblings.
Scarr (1992) identified four factors that can lead children from a single family (as
well as children from different families) to turn out very different from one another:
1. Genetic differences
2. Differences in treatment by parents and others
3. Differences in reactions to similar experiences
4. Different choices of environments
The most obvious reason for differences among children is that, except for
identical twins, every individual is genetically unique. All other siblings (includ-
ing fraternal twins) share 50% of their genes and differ in the
other 50%.
A second major source of variation among children is dif-
ferences in the treatment they receive from parents and other
people. This differential treatment is often associated with
preexisting differences in the children’s characteristics. For
example, parents tend to provide more sensitive care to easy-
going infants than to difficult ones; by the second year, parents
of difficult children are often angry with them even when the
children have done nothing wrong in the immediate situation
(van den Boom & Hoeksma, 1994). Teachers, likewise, tend
to provide positive attention and encouragement to pupils
who are learning well and are well behaved, but with pupils FO
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same family, often react to the same experi-
ence in completely different ways.

E N D U R I N G T H E M E S I N C H I L D D E V E L O P M E N T n 21
who are doing poorly and are disruptive, they tend to be openly critical and to deny
the pupils’ requests for special help (Good & Brophy, 1996).
In addition to being shaped by objective differences in the treatment they re-
ceive, children also are influenced by their subjective interpretations of the treat-
ment. A classic example occurs when each of a pair of siblings feels that their
parents favor the other. Siblings also often react differently to events that affect the
whole family. In one study, 69% of negative events, such as parents’ being laid off or
fired, elicited fundamentally different reactions from siblings (Beardsall & Dunn,
1992). Some children were very concerned at a parent’s loss of a job; others were
sure that everything would be okay.
A fourth major source of differences among children relates to the previously
discussed theme of the active child: As children grow older, they increasingly choose
activities and friends for themselves and thus influence their own subsequent de-
velopment. They may also accept or choose niches for themselves: within a family,
one child may become “the smart one,” another “the popular one,” another “the bad
one,” and so on (Scarr & McCartney, 1983). A child labeled by family members
as “the smart one” may strive to live up to the label; so, unfortunately, may a child
labeled “the troublemaker.”
As discussed in the section on nature and nurture and in the section on mech-
anisms of development, differences in biology and experience interact in com-
plex ways to create the infinite diversity of human beings. Thus, a study of 11- to
17-year-olds found that the grades of children who were highly engaged with
school changed in more positive directions than would have been predicted by their
genetic background or family environments alone ( Johnson, McGue, & Iacono,
2006). The same study revealed that children of high intelligence were less nega-
tively affected by adverse family environments than were other children. Thus,
children’s genes, their treatment by other people, their subjective reactions to their
experiences, and their choice of environments interact in ways that contribute to
differences among children, even ones in the same family.
7 Research and Children’s Welfare: How Can Research
Promote Children’s Well-Being?
Improved understanding of child development often leads to practical benefits.
Several examples have already been described, including the program for helping
children deal with their anger and the recommendations for fostering valid eyewit-
ness testimony from young children.
Another type of practical benefit arising from child-development research in-
volves educational innovations. One fascinating example comes from studies of
how children’s beliefs about intelligence influence their learning. Carol Dweck and
her colleagues (Dweck, 2006; Dweck & Leggett, 1988) have found that some chil-
dren (and adults) believe that intelligence is a fixed entity. They see each person as
having a certain amount of intelligence that is set at birth and cannot be changed
by experience. Other children (and adults) believe that intelligence is a changeable
characteristic that increases with learning and that the time and effort people put
into learning is the key determinant of their intelligence.
People who believe that intelligence increases with learning tend to react to
failure in more effective ways (Dweck, 2006). When they fail to solve a problem,
they more often persist on the task and try harder. Such persistence in the face
of failure is an important quality. As the great British Prime Minister Winston
Churchill once said, “Success is the ability to go from one failure to another with

22 n chapTer 1 AN INTRODUCTION TO CHILD DEVELOPMENT
no loss of enthusiasm.” In contrast, people who be-
lieve that intelligence is a fixed entity tend to give
up when they fail, because they think the problem
is too hard for them.
Building on this research regarding the relation
between beliefs about intelligence and persistence
in the face of difficulty, Blackwell, Trzesniewski,
and Dweck (2007) devised an effective educational
program for middle school students from low-
income backgrounds. They presented randomly se-
lected students with research findings about how
learning alters the brain in ways that improve sub-
sequent learning and thus “makes you smarter.”
Other randomly selected students from the same classrooms were presented with
research findings about how memory works. The investigators predicted that the
students who were told about the effects that learning has on the brain would
change their beliefs about intelligence in ways that would help them persevere in
the face of failure. In particular, the changed beliefs were expected to improve stu-
dents’ learning of mathematics, an area in which children often experience initial
failure.
This prediction was borne out. Children who were presented information about
how learning changes the brain and enhances intelligence subsequently improved
their math grades, whereas the other children did not. Children who initially be-
lieved that intelligence was an inborn, unchanging quality but who came to believe
that intelligence reflected learning showed especially large improvements. Perhaps
most striking, when the children’s teachers, who did not know which type of in-
formation each child had received, were asked if any of their students had shown
unusual improvement in motivation or performance, the teachers cited more than
three times as many students who had been given information about how learning
builds intelligence.
In subsequent chapters, we review many additional examples of how child de-
velopment research is being used to promote children’s welfare.
review:
The modern field of child development is in large part an attempt to answer a small set of
fundamental questions about children. These include:
1. How do nature and nurture jointly contribute to development?
2. How do children contribute to their own development?
3. Is development best viewed as continuous or discontinuous?
4. What mechanisms produce development?
5. How does the sociocultural context influence development?
6. Why are children so different from one another?
7. How can we use research to improve children’s welfare?
Methods for Studying Child Development
As illustrated in the preceding section, modern scientific research has advanced
the understanding of fundamental questions about child development well beyond
that of the historical figures who first raised the questions. This progress reflects the
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Screenshot from Brainology, a commer-
cially available educational program based
on the findings of Blackwell, Trzesniewski,
and Dweck (2007). The software, like the
research study, emphasizes that learning
makes children smarter by building new
connections within the brain.

WWW.BRAINOLOGY.US

M E T H O D S F O R S T U D Y I N G C H I L D D E V E L O P M E N T n 23
successful application of the scientific method to the study of child development.
In this section, we describe the scientific method and examine how its use has ad-
vanced understanding of child development.
The Scientific Method
The basic assumption of the scientific method is that all beliefs, no matter how
probable they seem and no matter how many people share them, may be wrong.
Therefore, until beliefs have been tested, they must be viewed as hypotheses, that
is, as educated guesses, rather than as truth. If a hypothesis is tested, and the evi-
dence repeatedly does not support it, the hypothesis must be abandoned no matter
how reasonable it seems.
Use of the scientific method involves four basic steps:
1. Choosing a question to be answered
2. Formulating a hypothesis regarding the question
3. Developing a method for testing the hypothesis
4. Using the data yielded by the method to draw a conclusion regarding the
hypothesis
To illustrate these steps, let’s make the question to be answered “What abilities
predict which children will become good readers?” A reasonable hypothesis might
be “Kindergartners who can identify the separate sounds within words will become
better readers than those who cannot.” A straightforward method for testing this
hypothesis would be to select a group of preschoolers, test their ability to identify
the separate sounds within words, and then, several years later, test the reading
skills of the same children. Research has, in fact, shown that kindergartners who are
aware of the component sounds within words later tend to read more skillfully than
their peers who lacked this ability as kindergartners. This pattern holds true regard-
less of whether the children live in the United States, Australia, Norway, or Sweden
(Furnes & Samuelsson, 2011). These results support the conclusion that kindergart-
ners’ ability to identify sounds within words predicts their later reading skill.
The first, second, and fourth of these steps are not unique to the scientific
method. As we have seen, great thinkers of the past also asked questions, formu-
lated hypotheses, and drew conclusions that were reasonable given the evidence
available to them. What distinguishes scientific research from nonscientific ap-
proaches is the third step: the methods used to test the hypotheses. When rigor-
ously employed, these research methods yield high-quality evidence that allows
investigators to progress beyond their initial hypotheses to draw firmly grounded
conclusions.
The Importance of Appropriate Measurement
For the scientific method to work, researchers must use measures that are directly
relevant to the hypotheses being tested. Even measures that initially seem reason-
able sometimes turn out to be less informative than originally thought. For ex-
ample, a researcher who hypothesized that a supplemental food program would
help children suffering from malnutrition might evaluate the program on the basis
of weight gain from just before the program to just after it. However, weight is an
inadequate measure of nutrition: Providing unlimited supplies of Cheetos would
probably produce weight gain but not improve nutrition, and many people are
obese yet malnourished (Sawaya et al., 1995). Better measures of nutrition would
scientific method n an approach to
testing beliefs that involves choosing
a question, formulating a hypothesis,
testing the hypothesis, and drawing a
conclusion
hypotheses n educated guesses

24 n chapTer 1 AN INTRODUCTION TO CHILD DEVELOPMENT
include whether more adequate levels of essential nutrients were present in the
children’s bloodstreams at the end of the study (Shetty, 2006).
Regardless of the particular measure used, many of the same criteria determine
whether a measure is a good one. One key criterion has already been noted—the
measure must be directly relevant to the hypothesis. Two other qualities that good
measures must possess are reliability and validity.
reliability The degree to which independent measurements of a behavior under
study are consistent is referred to as reliability. One important type of consistency,
interrater reliability, indicates how much agreement there is in the observations
of different raters who witness the same behavior. Sometimes the observations are
qualitative, as when raters classify a baby’s attachment to her mother as “secure” or
“insecure.” Other times the observations are quantitative, as when raters score on
a scale of 1 to 10 how upset babies become when they are presented with an un-
familiar noisy toy or a boisterous stranger. In both cases, interrater reliability is at-
tained when the raters’ observations are in close agreement—as when, for example,
Baby A in a group being observed for a particular behavior gets a 6 or 7 from all the
raters, Baby B gets a 3 or 4, Baby C gets an 8 or 9, and so on. Without such close
agreement, one cannot have confidence in the research findings, because there is no
way to tell which (if any) rating was accurate.
A second important type of consistency is test–retest reliability. This type of
reliability is attained when measures of a child’s performance on the same test,
administered under the same conditions, are similar on two or more occasions.
Suppose, for example, that researchers presented a vocabulary test to a group of
children on two occasions one week apart. If the test is reliable, those children who
scored highest on the first testing should also score highest on the second, because
none of the children’s vocabularies would have changed much over such a short
period. As in the example of interrater reliability, a lack of test–retest reliability
would make it impossible to know which result (if either) accurately reflected each
child’s status.
Validity The validity of a test or experiment refers to the degree to which it mea-
sures what it is intended to measure. Researchers strive for two types of validity:
internal and external. Internal validity refers to whether effects observed within
experiments can be attributed with confidence to the factor that the researcher is
testing. For example, suppose that a researcher tests the effectiveness of a type of
psychotherapy for depression by administering it to a number of depressed adoles-
cents. If three months later many of the adolescents are no longer depressed, can it
be concluded that this type of psychotherapy caused the improvement? No, because
the students’ recovery may have been due to the mere passage of time. Moods fluc-
tuate, and many adolescents who are depressed at any given time will be happier at
a later date even without psychotherapy. In this example, the passage of time is a
source of internal invalidity, because the factor believed to cause the improvement
(the psychotherapy) may have had no effect.
External validity, in contrast, refers to the ability to generalize research findings
beyond the particulars of the research in question. Studies of child development are
almost never intended to apply only to the particular children and research meth-
ods involved in a given study. Rather, the goal is to draw conclusions that apply
to children more generally. Thus, the findings of a single experiment are only the
first step in determining the external validity of the results. Additional studies with
participants from different backgrounds and with different research methods are
reliability n the degree to which inde-
pendent measurements of a given
behavior are consistent
interrater reliability n the amount of
agreement in the observations of different
raters who witness the same behavior
test–retest reliability n the degree of
similarity of a child’s performance on two
or more occasions
validity n the degree to which a test
measures what it is intended to measure
internal validity n the degree to which
effects observed within experiments
can be attributed to the factor that the
researcher is testing
external validity n the degree to which
results can be generalized beyond the
particulars of the research

M E T H O D S F O R S T U D Y I N G C H I L D D E V E L O P M E N T n 25
invariably needed to establish the external validity of the findings. (Table 1.3 sum-
marizes the key properties of behavioral measures.)
Contexts for Gathering Data About Children
Researchers obtain data about children in three main contexts: interviews, natu-
ralistic observation, and structured observation. In the following sections, we con-
sider how gathering data in each context can help answer different questions
about children.
Interviews
The most obvious way to collect data about children is to go straight to the source
and ask the children themselves about their lives. One type of interview, the struc­
tured interview, is especially useful when the goal is to collect self-reports on the
same topics from everyone being studied. For example, Valeski and Stipek (2001)
asked kindergartners and 1st-graders questions regarding their feelings about
school (How much does your teacher care about you? How do you feel when you’re
at school?) and also questions about their beliefs about their academic competence
(How much do you know about numbers? How
good are you at reading?). The children’s general
attitude toward school and their feelings about
their relationship with their teacher proved to be
positively related to their beliefs about their com-
petence in math and reading. Asking large num-
bers of children identical questions about their
feelings and beliefs provides a quick and straight-
forward way for researchers to learn about chil-
dren’s beliefs and attitudes.
A second type of interview, the clinical inter­
view, is especially useful for obtaining in-depth
information about an individual child. In this ap-
proach, the interviewer begins with a set of pre-
pared questions, but if the child says something
intriguing, the interviewer can depart from the
script to follow up on the child’s lead.
TABLE 1.3
Key properties of Behavioral Measures
Property Question of Interest
Relevance to hypotheses Do the hypotheses predict in a straightforward way what should happen on
these measures?
Interrater reliability Do different raters who observe the same behavior classify or score it the
same way?
Test–retest reliability Do children who score higher on a measure at one time also score higher
on the measure at other times?
Internal validity Can effects within the experiment be attributed to the variables that the
researcher intentionally manipulated?
External validity How widely can the findings be generalized to different children in
different places at different times?
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One-on-one clinical interviews like this one
can elicit unique in-depth information about
a child.
structured interview n a research pro-
cedure in which all participants are asked
to answer the same questions
clinical interview n a procedure in
which questions are adjusted in accord
with the answers the interviewee provides

26 n chapTer 1 AN INTRODUCTION TO CHILD DEVELOPMENT
The usefulness of clinical interviews can be seen in the case of Bobby, a 10-year-
old child who was assessed for symptoms of depression (Schwartz & Johnson,
1985). When the interviewer asked him about school, Bobby said that he did not
like it because the other children disliked him and he was bad at sports. As he put
it, “I’m not really very good at anything” (p. 214). To explore the source of this
sad self-description, the interviewer asked Bobby what he would wish for if three
wishes could be granted. Bobby replied, “I would wish that I was the type of boy my
mother and father want, I would wish that I could have friends, and I would wish
that I wouldn’t feel sad so much” (p. 214). Such heartrending comments provide a
sense of the painful subjective experience of this depressed child, one that would be
impossible to obtain from methods that were not tailored to the individual.
As with all contexts for collecting data, interviews have both strengths and weak-
nesses. On the positive side, they yield a great deal of data quickly and can provide
in-depth information about individual children. On the negative side, answers to
interview questions often are biased. Children (like adults) often avoid disclosing
facts that show them in a bad light, distort the way that events happened, and fail
to understand their own motivations (Wilson & Dunn, 2004). These limitations
have led many researchers to use observational methods that allow them to witness
the behavior of interest for themselves.
Naturalistic Observation
When the primary research goal is to describe how children behave in their usual
environments—homes, schools, playgrounds, and so on—naturalistic observation
is the method of choice for gathering data. In this approach, observers try to remain
unobtrusively in the background in the chosen setting, allowing them to see the
relevant behaviors while minimizing the chances that their presence will influence
those behaviors.
A classic example of naturalistic observation is Gerald Patterson’s (1982) com-
parative study of family dynamics in “troubled” and “typical” families. The troubled
families were defined by the presence of at least one child who had been labeled
“out of control” and referred for treatment by a school, court, or mental health pro-
fessional. The typical families were defined by the fact that none of the children in
them showed signs of serious behavioral difficulties. Income levels and children’s
ages were the same for the troubled and typical families.
To observe the frequency with which children and parents engaged in nega-
tive behaviors—teasing, yelling, whining, criticizing, and so on—research assis-
tants repeatedly observed dinnertime interactions in both
troubled and typical homes. To accustom family mem-
bers to his or her presence, the research assistant for each
family made several home visits before beginning to col-
lect data.
The researchers found that the behaviors and attitudes
of both parents and children in the troubled families dif-
fered strikingly from those of their counterparts in the
typical families. Parents in the troubled families were
more self-absorbed and less responsive to their children
than were parents in the typical households. Children in
the troubled families responded to parental punishment
by becoming more aggressive, whereas children in the
typical households responded to punishment by becoming MO
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psychologists sometimes observe family
interactions around the dinner table,
because mealtime comments can evoke
strong emotions.
naturalistic observation n examina-
tion of ongoing behavior in an environ-
ment not controlled by the researcher

M E T H O D S F O R S T U D Y I N G C H I L D D E V E L O P M E N T n 27
less aggressive. In the troubled families, interactions often fell into a vicious cycle
in which:
n The child acted in a hostile or aggressive manner, for example, by defying a
parent’s request to clean up his or her room.
n The parent reacted angrily, for example, by shouting at the child to obey.
n The child escalated the level of hostility, for example, by yelling back.
n The parent ratcheted up the aggression even further, perhaps by spanking the
child.
As Patterson’s study suggests, naturalistic observations are particularly useful for
illuminating everyday social interactions, such as those between children and
parents.
Although naturalistic observation can yield detailed information about certain
aspects of children’s everyday lives, it also has important limitations. One is that
naturally occurring contexts vary on many dimensions, so it is often hard to know
which ones influenced the behavior of interest. For example, it was clear in the
Patterson study that the interactions of troubled families differed from those of the
more harmonious families, but the interactions and family histories differed in so
many ways that it was impossible to specify their contributions to the current situ-
ation. A second limitation of naturalistic studies is that many behaviors of interest
occur only occasionally in the everyday environment, which reduces researchers’
opportunities to learn about them. A means for overcoming both limitations is the
method known as structured observation.
Structured Observation
When using structured observation, researchers design a situation that will elicit
behavior that is relevant to a hypothesis and then observe how different children
behave in that situation. The researchers then relate the observed behaviors to char-
acteristics of the child, such as age, sex, or personality, and to the child’s behavior in
other situations that are also observed.
In one such study, Kochanska, Coy, and Murray (2001) investigated the links
between 2- and 3-year-olds’ compliance with their mother’s requests to forego ap-
pealing activities and their compliance with her requests that they participate in
unappealing ones. Mothers brought their toddlers to a laboratory room that had
a number of especially attractive toys sitting on a shelf and a great many less at-
tractive toys scattered around the room. The experimenter asked each mother to
tell her child that he or she could play with any of the toys except the ones on the
shelf. Raters observed the children through a one-way mirror over the next few
minutes and classified them as complying with their mother’s request wholeheart-
edly, grudgingly, or not at all. Then the experimenter asked the mother to leave
the room and observed whether the child played with the “forbidden” toys in the
mother’s absence.
The researchers found that children who had complied wholeheartedly in the
first instance tended to avoid playing with the forbidden toys for a longer time in
the second. Moreover, these children were also more likely to comply with their
mother’s request that they put away the many toys on the floor after she left the
room. When retested near their 4th birthday, most children showed the same type
of compliance as they had as toddlers. Overall, the results indicated that the quality
of young children’s compliance with their mother’s requests is a somewhat stable,
general property of the mother–child relationship.
structured observation n a method
that involves presenting an identical situ-
ation to each child and recording the
child’s behavior
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Temptation is everywhere, but children who
are generally compliant with their moth-
er’s requests when she is present are also
more likely to resist temptation when she is
absent (like this boy, the nephew of one of
the authors, whose reach, despite appear-
ances, stopped just short of the cake).

28 n chapTer 1 AN INTRODUCTION TO CHILD DEVELOPMENT
This type of structured observation offers an important advantage over natural-
istic observation: it ensures that all the children being studied encounter identical
situations. This allows direct comparisons of different children’s behavior in a given
situation and, as in the research just discussed, also makes it possible to establish
the generality of each child’s behavior across different tasks. On the other hand,
structured observation does not provide as extensive information about individual
children’s subjective experience as do interviews, nor can it provide the open-ended,
everyday kind of data that naturalistic observation can yield.
As these examples suggest, which data-gathering approach is best depends on
the goals of the research. (Table 1.4 summarizes the advantages and disadvantages
of interviews, naturalistic observation, and structured observation as contexts for
gathering data.)
Correlation and Causation
People differ along an infinite number of variables, that is, attributes that vary
across individuals and situations, such as age, sex, activity level, socioeconomic sta-
tus, particular experiences, and so on. A major goal of child-development research
is to determine how these and other major variables are related to one another,
both in terms of associations and in terms of cause–effect relations. In the follow-
ing sections, we consider the research designs that are used to examine each type
of relation.
Correlational Designs
The primary goal of studies that use correlational designs is to determine whether
children who differ in one variable also differ in predictable ways in other variables.
For example, a researcher might examine whether toddlers’ aggressiveness is related
to the number of hours they spend in day care or whether adolescents’ popularity
is related to their self-control.
TABLE 1.4
advantages and Disadvantages of Three contexts for Gathering Data
Data-Gathering
Situation
Features Advantages Disadvantages
Interview Children answer questions asked
either in person or on a questionnaire.
Can reveal children’s subjective experience.
Structured interviews are inexpensive
means for collecting in-depth data about
individuals.
Clinical interviews allow flexibility for
following up unexpected comments.
Reports are often biased to reflect favorably on
interviewee.
Memories of interviewees are often inaccurate
and incomplete.
Prediction of future behaviors often is
inaccurate.
Naturalistic
observation
Activities of children in everyday
settings are observed.
Useful for describing behavior in everyday
settings.
Helps illuminate social interaction processes.
Difficult to know which aspects of situation are
most influential.
Limited value for studying infrequent behaviors.
Structured
observation
Children are brought to laboratory and
presented prearranged tasks.
Insures that all children’s behaviors are
observed in same context.
Allows controlled comparison of children’s
behavior in different situations.
Context is less natural than in naturalistic
observation.
Reveals less about subjective experience than
interviews.
variables n attributes that vary across
individuals and situations, such as age,
sex, and popularity
correlational designs n studies
intended to indicate how two variables are
related to each other

M E T H O D S F O R S T U D Y I N G C H I L D D E V E L O P M E N T n 29
The association between two variables is known as their correlation. When
variables are strongly correlated, knowing a child’s score on either variable allows
accurate prediction of the child’s score on the other. For example, the fact that
the number of hours per week that children spend reading correlates highly with
their reading-test scores (Guthrie et al., 1999) means that a child’s reading-test
score can be accurately predicted if one knows how much time the child spends
reading. It also means that the number of hours the child spends reading can be
predicted if one knows the child’s reading-test score.
Correlations range from 1.00, the strongest positive correlation, to 21.00, the
strongest negative correlation. The direction is positive when high values of one
variable are associated with high values of the other and low values of one are as-
sociated with low values of the other; the direction is negative when high values of
one are associated with low values of the other. Thus, the correlation between time
spent reading and reading-test scores is positive, because children who spend high
amounts of time reading also have high reading-test scores; the correlation between
obesity and running speed is negative, because the more obese the child, the slower
his or her running speed. (For a more in-depth discussion of how correlations work,
see the Appendix.)
Correlation Does Not Equal Causation
When two variables are strongly correlated and there is a plausible cause–effect
relation between them, it often is tempting to infer that one causes the other.
However, this inference is not justified, for two reasons. The first is the direction­
of­causation problem: a correlation does not indicate which variable is the cause
and which variable is the effect. In the above example of the correlation between
time spent reading and reading achievement, greater time spent reading might
cause increased reading achievement. On the other hand, the cause–effect relation
could run in the opposite direction: greater reading skill might cause children to
spend more time reading, because reading faster and with greater comprehension
makes reading more enjoyable.
The second reason that correlation does not imply causation is the third­
variable problem: the correlation between two variables may actually be the result
of some third, unspecified variable. In the reading example, for instance, rather than
greater reading achievement being caused by greater reading time, or vice versa,
both of these aspects of reading could be caused by growing up in a family that val-
ues knowledge and intelligence.
Recognizing that correlation does not imply causation is crucial for interpret-
ing accounts of research. Even findings published in prestigious research journals
can easily be misinterpreted. For example, based on a correlation between children
younger than 2 years sleeping with a night-light and their later becoming near-
sighted, an article in the prestigious journal Nature concluded that the light was
harmful to visual development (Quinn et al., 1999). Not surprisingly, the claim
received considerable publicity in the popular media (e.g., Torassa, 2000). Sub-
sequent research, however, showed that the inference about causation was wrong.
What actually seems to have happened is that the nearsighted infants generally
had nearsighted parents, and the nearsighted parents, for unknown reasons, more
often placed nightlights in their infants’ rooms (Gwiazda et al., 2000; Zadnik et
al., 2000). As the example illustrates, even seemingly straightforward inferences of
causation, based on correlational evidence, frequently prove to be wrong.
correlation n the association between
two variables
direction-of-causation problem n
the concept that a correlation between
two variables does not indicate which, if
either, variable is the cause of the other
third-variable problem n the concept
that a correlation between two variables
may stem from both being influenced by
some third variable

30 n chapTer 1 AN INTRODUCTION TO CHILD DEVELOPMENT
If correlation does not imply causation, why do researchers often use correla-
tional designs? One major reason is that the influence of many variables of great
interest—age, sex, race, and social class among them—cannot be studied experi-
mentally (see the next section) because researchers cannot manipulate them; that
is, they cannot assign participants to one sex or another, to one SES or another,
and so on. Consequently, these variables can only be studied through correlational
methods. Correlational designs are also of great use when the goal is to describe re-
lations among variables rather than to identify cause–effect relations among them.
If, for example, the research goal is to discover how moral reasoning, empathy, anxi-
ety, and popularity are related to one another, correlational designs would almost
certainly be employed.
Experimental Designs
If correlational designs are insufficient to indicate cause–effect relations, what type
of approach is sufficient? The answer is experimental designs. The logic of ex-
perimental designs can be summarized quite simply: If children in one group are
exposed to a particular experience and subsequently behave differently from a com-
parable group of children who were not exposed to the experience or were exposed
to a different experience, then the subsequent differences in behavior must have
resulted from the differences in experience.
Two techniques are crucial to experimental designs: random assignment of par-
ticipants to groups, and experimental control. Random assignment involves assign-
ing the participants to one experimental group or another according to chance so
that the groups are comparable at the outset. This comparability is crucial for being
able to infer that it was the varying experiences to which the groups were exposed
in the experiment that caused the later differences between them. Otherwise, those
differences might have arisen from some preexisting difference between the people
in the groups.
Say, for example, that researchers wanted to compare the effectiveness of two
interventions for helping depressed mothers improve their relationship with their
infant—providing the mothers with home visits from trained therapists versus
providing them with supportive phone calls from such therapists. If the research-
ers provided the home visits to families in one neighborhood and the supportive
phone calls to families in another neighborhood, it would be unclear whether any
differences in mother–infant relationships following the experiment were
caused by differences between the effectiveness of the two types of support
or by differences between the families in the two areas. Depressed mothers
in one neighborhood might suffer from less severe forms of depression than
mothers in the other, or they might have greater access to other support, such
as close families, mental health centers, or parenting programs.
In contrast, when groups are created through random assignment and
include a reasonably large number of participants (typically 20 or more
per group), initial differences between the groups tend to be minimal. For
example, if 40 families with mothers who suffer from depression are di-
vided randomly into two experimental groups, each group is likely to have
roughly equal numbers of families from each neighborhood. Similarly, each
group is likely to include a few mothers who are extremely depressed, a few
with mild forms of depression, and many in between, as well as a few in-
fants who have been severely affected by their mother’s depression, a few RO
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Depressed mothers often have difficulty pro-
viding sensitive parenting; home visits from
trained therapists can help alleviate this
problem.
experimental designs n a group of
approaches that allow inferences about
causes and effects to be drawn
random assignment n a procedure in
which each child has an equal chance of
being assigned to each group within an
experiment

M E T H O D S F O R S T U D Y I N G C H I L D D E V E L O P M E N T n 31
who have been minimally affected, and many in be-
tween. The logic implies that groups created through
random assignment should be comparable on all vari-
ables except the different treatment that people in the
experimental groups encounter during the experi-
ment. Such an experiment was in fact conducted, and
it showed that home visits helped depressed mothers
more than supportive phone calls did (Van Doesum
et al., 2008).
The second essential characteristic of an experi-
mental design, experimental control, refers to the
ability of the researcher to determine the specific ex-
periences that children in each group encounter dur-
ing the study. In the simplest experimental design, one
with two conditions, the groups are often referred to
as the “experimental group” and the “control group.”
Children in the experimental group are presented
with the experience of interest; children in the control
group are treated identically except that they are not
presented with the experience of interest or are pre-
sented with a different experience that is expected to
have less effect on the variables being tested.
The experience that children in the experimental
group receive, and that children in the control group do not receive, is referred to as
the independent variable. The behavior that is hypothesized to be affected by ex-
posure to the independent variable is referred to as the dependent variable. Thus, if
a researcher hypothesized that showing schoolchildren an anti-bullying film would
reduce school bullying, the researcher might randomly assign some children in a
school to view the film and other children in the same school to view a film about
a different topic. In this case, the anti-bullying film would be the independent vari-
able, and the amount of bullying after the children watched it would be the depen-
dent variable. If the independent variable had the predicted effect, children who saw
the anti-bullying film would show less bullying after watching it than children who
saw the other film.
One illustration of how experimental designs allow researchers to draw con-
clusions about causes and effects is a study that tested the hypothesis that televi-
sion shows running in the background lower the quality of infants’ and toddlers’
play (Schmidt et al., 2008). The independent variable was whether or not a televi-
sion program was on in the room where the participants were playing; the depen-
dent variables were a variety of measures of children’s attention to the television
program and of the quality of their play. The television program that was playing
was Jeopardy!, which presumably would have been of little interest to the 1- and
2-year-olds in the study; indeed, they looked at it an average of only once per
minute and only for a few seconds at a time. Nonetheless, the television show
disrupted the children’s play, reducing the length of play episodes and the chil-
dren’s focus on their play. These findings indicate that there is a causal, and nega-
tive, relation between background exposure to television shows and the quality of
young children’s play.
Experimental designs are the method of choice for establishing causal rela-
tions, a central goal of scientific research. However, as noted earlier, experimental
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The quality of infants’ and toddlers’ play
is adversely affected by a television being
on in the same room. This is true for even
the most precocious children, such as
this 1-year-old, the grandson of one of the
authors.
experimental control n the ability of
researchers to determine the specific
experiences that children have during the
course of an experiment
experimental group n a group of chil-
dren in an experimental design who are
presented the experience of interest
control group n the group of children
in an experimental design who are not
presented the experience of interest but
in other ways are treated similarly
independent variable n the experience
that children in the experimental group
receive and that children in the control
group do not receive
dependent variable n a behavior that
is measured to determine whether it is
affected by exposure to the independent
variable

32 n chapTer 1 AN INTRODUCTION TO CHILD DEVELOPMENT
designs cannot be applied to all issues of interest. For example, hypotheses about
why boys tend to be more physically aggressive than girls cannot be tested experi-
mentally because gender cannot be randomly assigned to children. In addition,
many experimental studies are conducted in laboratory settings; this improves
experimental control but can raise doubts about the external validity of the find-
ings, that is, whether the findings from the lab apply to the outside world. (The
advantages and disadvantages of correlational and experimental designs are sum-
marized in Table 1.5.)
Designs for Examining Development
A great deal of research on child development focuses on the ways in which chil-
dren change or remain the same as they grow older and gain experience. To study
development over time, investigators use three types of research designs: cross-
sectional, longitudinal, and microgenetic.
Cross-Sectional Designs
The most common and easiest way to study changes and continuities with age
is to use the cross­ sectional approach. This method compares children of dif-
ferent ages on a given behavior, ability, or characteristic, with all the children
being studied at roughly the same time—for example, within the same month.
In one cross-sectional study, Evans, Xu, and Lee (2011) examined the develop-
ment of lying in Chinese 3-, 4-, and 5-year-olds. The children played a game
in which, to win a prize, they needed to guess the type of object hidden under
an upside-down paper cup. However, before the child could guess, the experi-
menter left the room after telling the child not to peek while she was gone.
The cup was so fully packed with candies that if the child peeked, some would
spill out and it would be virtually impossible for the child to put them all back
under the cup.
At all ages, many children peeked and then denied doing so. However, 5-year-
olds lied more often, and their lies were cleverer. For example, many 5-year-olds
explained away the presence of candies on the table by saying that they accidentally
knocked over the cup with their elbow; other 5-year-olds destroyed the evidence
by eating it. Three-year-olds were the least-skilled fibbers, generating implausible
TABLE 1.5
advantages and Disadvantages of correlational and experimental Designs
Type of Design Features Advantages Disadvantages
Correlational Comparison of existing groups of children
or examination of relations among each
child’s scores on different variables.
Only way to compare many groups of interest
(boys–girls, rich–poor, etc.).
Only way to establish relations among many
variables of interest (IQ and achievement,
popularity and happiness, etc.).
Third-variable problem.
Direction-of-causation problem.
Experimental Random assignment of children to groups
and experimental control of procedures
presented to each group.
Allows causal inferences because design rules
out direction-of-causation and third-variable
problems.
Allows experimental control over the exact
experiences that children encounter.
Need for experimental control often leads
to artificial experimental situations.
Cannot be used to study many differences
and variables of interest, such as age, sex,
and temperament.
cross-sectional design n a research
method in which children of different
ages are compared on a given behavior or
characteristic over a short period

M E T H O D S F O R S T U D Y I N G C H I L D D E V E L O P M E N T n 33
excuses such as that some other child entered the room and knocked over the cup
or that the candies came out by themselves.
Cross-sectional designs are useful for revealing similarities and differences
between older and younger children. However, they do not yield information
about the stability of behavior over time or about the patterns of change shown
by individual children. This is where longitudinal approaches are especially
valuable.
Longitudinal Designs
The longitudinal approach involves following a group of children over a sub-
stantial period (usually at least a year) and observing changes and continuities in
these children’s development at regular intervals during that time. In one lon-
gitudinal study, Brendgen and colleagues (2001) examined children’s popularity
with classmates each year from the time they were
7-year-olds to the time they were 12-year-olds. The
popularity of most children proved to be quite sta-
ble over this period; a substantial number of chil-
dren were popular in the large majority of years,
and quite a few others were unpopular throughout.
At the same time, some individuals showed idio-
syncratic patterns of change from year to year; the
same child might be popular at age 8, unpopular at
age 10, and of average popularity at age 12. Such
findings about the stability of individual differences
over time and about individual children’s patterns of
change could only have been obtained in a longitu-
dinal design.
If longitudinal designs are so useful for reveal-
ing stability and change over time, why are cross-
sectional designs more common? The reasons are
mainly practical. Studying the same children over
long periods involves the difficult task of locating the children for each re-exami-
nation. Inevitably, some of the children move away or stop participating for other
reasons. Such loss of participants may call into question the validity of the find-
ings, because the children who do not continue may differ from those who par-
ticipate throughout. Another threat to the validity of longitudinal designs is the
possible effects of the repeated testing. For example, repeatedly taking IQ tests
could familiarize children with the type of items on the tests, thus improving the
children’s scores. For these reasons, longitudinal designs are used primarily when
the main issues are stability and change in individual children over time—issues
that can be studied only longitudinally. When the central developmental issue
involves age-related changes in typical performance, cross-sectional studies are
more commonly used.
Microgenetic Designs
An important limitation of both cross-sectional and longitudinal designs is that
they provide only a broad outline of the process of change. Microgenetic designs,
in contrast, are specifically designed to provide an in-depth depiction of the pro-
cesses that produce change (Miller & Coyle, 1999; Siegler, 2006). The basic idea
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Being excluded is no fun for anyone. Longi-
tudinal research has been used to determine
whether the same children are unpopular
year after year or whether popularity changes
over time.
longitudinal design n a method of
study in which the same children are
studied twice or more over a substantial
length of time
microgenetic design n a method of
study in which the same children are
studied repeatedly over a short period

34 n chapTer 1 AN INTRODUCTION TO CHILD DEVELOPMENT
of this approach is to recruit children who are thought to be on the verge of an
important developmental change, heighten their exposure to the type of experi-
ence that is believed to produce the change, and then intensively study the change
as it is occurring. Microgenetic designs are like longitudinal ones in repeatedly test-
ing the same children over time. They differ in that microgenetic studies typically
include a greater number of sessions presented over a shorter time than in a
longitudinal study.
Siegler and Jenkins (1989) used a microgenetic design to study how young
children discover the counting­on strategy for adding two small numbers.
This strategy involves counting up from the larger addend the number of
times indicated by the smaller addend; for example, when asked the answer
to 3 1 5, a child who was counting-on would start from the addend 5 and
say or think “6, 7, 8” before answering “8.” Prior to discovering this strategy,
children usually solve addition problems by counting from 1. Counting from
the larger addend rather than from 1 reduces the amount of counting, pro-
ducing faster and more accurate solutions.
To observe the discovery process, the researchers selected 4- and 5-year-
olds who did not yet use counting-on but who knew how to add by count-
ing from 1. Over an 11-week period, these children received many addition
problems—far more than they would normally encounter before entering
school—and each child’s behavior was videotaped for every problem. This
approach allowed the researchers to identify exactly when each child discov-
ered the counting-on strategy.
Examination of the problems immediately preceding the discovery re-
vealed a surprising fact: necessity is not always the mother of invention.
Quite a few children discovered the counting-on strategy while working on
easy problems that they previously had solved correctly by counting from 1.
The microgenetic method also revealed that children’s very first use of the new
strategy often was accompanied by insight and excitement, like that shown by
Lauren:
Experimenter: How much is 6 1 3?
Lauren: (long pause) 9.
E: OK, how did you know that?
L: I think I said . . . I think I said . . . oops, um . . . 7 was 1, 8 was 2, 9 was 3.
E: How did you know to do that? Why didn’t you count 1, 2, 3, 4, 5, 6, 7, 8, 9?
L: (with excitement) ’Cause then you have to count all those numbers.
(Siegler & Jenkins, 1989, p. 66)
Despite her insightful explanation of counting-on and her excitement over
discovering it, Lauren, and most other children, only gradually increased their
use of the new strategy on subsequent problems. Many other microgenetic stud-
ies have also shown that generalization of new strategies tends to be slow (Kuhn
& Franklin, 2006).
As this example illustrates, microgenetic methods provide insight into the pro-
cess of change over brief periods. However, unlike standard longitudinal methods,
microgenetic designs do not yield information about stability and change over long
periods. They therefore are typically used when the basic pattern of age-related
change has already been established and the goal becomes to understand how the
changes occur. (Table 1.6 outlines the strengths and weaknesses of the three ap-
proaches to studying changes with age and experience: cross-sectional, longitudi-
nal, and microgenetic designs.)
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Discovering how to solve problems is an
inherently rewarding experience. Micro-
genetic designs can provide insight into both
the process of discovery and children’s emo-
tional response to it.
counting-on strategy n counting up
from the larger addend the number of
times indicated by the smaller addend

M E T H O D S F O R S T U D Y I N G C H I L D D E V E L O P M E N T n 35
Ethical Issues in Child-Development Research
All research with human beings raises ethical issues, and this is especially the case
when the research involves children. Researchers have a vital responsibility to antici-
pate potential risks that the children in their studies may encounter, to minimize such
risks, and to make sure that the benefits of the research outweigh any potential harm.
The Society for Research on Child Development, an organization devoted to
research on children, has formulated a code of ethical conduct for investigators to
follow (SRCD Governing Council, 2007). Some of the most important ethical
principles in the code are:
n Be sure that the research does not harm children physically or psychologically.
n Obtain informed consent for participating in the research, preferably in
writing, from parents or other responsible adults and also from children if
they are old enough that the research can be explained to them. The experi-
menter should inform children and relevant adults of all aspects of the research
that might influence their willingness to participate and should explain that
refusing to participate will not result in any adverse consequences to them.
n Preserve individual participants’ anonymity, and do not use information for
purposes other than that for which permission was given.
n Discuss with parents or guardians any information yielded by the investigation
that is important for the child’s welfare.
n Try to counteract any unforeseen negative consequences that arise during the
research.
n Correct any inaccurate impressions that the child may develop in the course of
the study. When the research has been completed, explain the main findings to
participants at a level they can understand.
Recognizing the importance of such ethical issues, universities and governmental
agencies have established institutional review boards made up of independent scien-
tists and sometimes others from the community. These boards evaluate the proposed
research to ensure that it does not violate ethics guidelines. However, the individual
investigator is in the best position to anticipate potential problems and bears the
ultimate responsibility for seeing that his or her study meets high ethical standards.
TABLE 1.6
advantages and Disadvantages of Designs for Studying Development
Design Features Advantages Disadvantages
Cross-sectional Children of different ages are
studied at a single time.
Yields useful data about differences among
age groups.
Quick and easy to administer.
Uninformative about stability of individual
differences over time.
Uninformative about similarities and differences
in individual children’s patterns of change.
Longitudinal Children are examined repeatedly
over a prolonged period.
Indicates the degree of stability of individual
differences over long periods.
Reveals individual children’s patterns of
change over long periods.
Difficult to keep all participants in study.
Repeatedly testing children can threaten
external validity of study.
Microgenetic Children are observed intensively
over a relatively short period while
a change is occurring.
Intensive observation of changes while they are
occurring can clarify process of change.
Reveals individual change patterns over short
periods in considerable detail.
Does not provide information about typical
patterns of change over long periods.
Does not yield data regarding change patterns
over long periods.

36 n chapTer 1 AN INTRODUCTION TO CHILD DEVELOPMENT
review:
The scientific method, in which all hypotheses are treated as potentially incorrect, has al-
lowed contemporary understanding of child development to progress well beyond the under-
standing of even the greatest thinkers of the past. This progress has been built on a base of
four types of innovations:
1. Measures that are directly relevant to the main hypotheses of the study
2. Data-gathering situations that yield useful information about children’s behavior, such as
interviews, naturalistic observations, and structured observations
3. Designs that allow identification of associations and cause–effect relations among vari-
ables, notably correlational and experimental designs
4. Designs that allow analysis of the continuities and changes that occur with age and expe-
rience, notably cross-sectional, longitudinal, and microgenetic designs
Conducting scientific experiments also requires meeting high ethical standards, includ-
ing not in any way harming the children who participate; obtaining informed consent for their
participation in the research; preserving anonymity of all participants; and, after the study, ex-
plaining the findings to parents and, when possible, to children, at a level they can understand.
chapter summary:
Why Study Child Development?
n Learning about child development is valuable for many rea-
sons: it can help us become better parents, inform our views
about social issues that affect children, and improve our under-
standing of human nature.
Historical Foundations of the Study of Child
Development
n Great thinkers such as Plato, Aristotle, Locke, and
Rousseau raised basic questions about child development
and proposed interesting hypotheses about them, but they
lacked the scientific methods to answer them. Early scientific
approaches, such as those of Freud and Watson, began the
movement toward modern research-based theories of child
development.
Enduring Themes in Child Development
n The field of child development is an attempt to answer a set of
fundamental questions:
1. How do nature and nurture together shape development?
2. How do children shape their own development?
3. In what ways is development continuous, and in what ways
is it discontinuous?
4. How does change occur?
5. How does the sociocultural context influence development?
6. How do children become so different from one another?
7. How can research promote children’s well-being?
n Every aspect of development, from the most specific behavior
to the most general trait, reflects both people’s biological
endowment (their nature) and the experiences that they have
had (their nurture).
n Even infants and young children actively contribute to their
own development through their attentional patterns, use of
language, and choices of activities.
n Many developments can appear either continuous or discontin-
uous, depending on how often and how closely we look at them.
n The mechanisms that produce developmental changes involve
a complex interplay among experiences, genes, and brain struc-
tures and activities.
n The contexts that shape development include the people with
whom children interact directly, such as family and friends;
the institutions in which they participate, such as schools and
religious organizations; and societal beliefs and values, such as
those related to race, ethnicity, and social class.
n Individual differences, even among siblings, reflect differences
in children’s genes, in their treatment by other people, in their
interpretations of their own experiences, and in their choices of
environments.
n Principles, findings, and methods from child-development
research are being applied to improve the quality of children’s
lives.
Methods for Studying Child Development
n The scientific method has made possible great advances in
understanding children. It involves choosing a question, for-
mulating a hypothesis relevant to the question, developing
a method to test the hypothesis, and using data to decide
whether the hypothesis is correct.

C H A P T E R S U M M A R Y n 37
n For a measure to be useful, it must be directly relevant to the
hypotheses being tested, reliable, and valid. Reliability means
that independent observations of a given behavior are consis-
tent. Validity means that a measure assesses what it is intended
to measure.
n Among the main situations used to gather data about children
are interviews, naturalistic observation, and structured obser-
vation. Interviews are especially useful for revealing children’s
subjective experience. Naturalistic observation is particu-
larly useful when the primary goal is to describe how children
behave in their everyday environments. Structured observation
is most useful when the main goal is to describe how different
children react to the identical situation.
n Correlation does not imply causation. The two differ in that
correlations indicate the degree to which two variables are
associated, whereas causation indicates that changing the value
of one variable will change the value of the other.
n Correlational designs are especially useful when the goal is to
describe relations among variables or when the variables of
interest cannot be manipulated because of technical or prac-
tical considerations.
n Experimental designs are especially valuable for revealing the
causes of children’s behavior.
n Data about development can be obtained through cross-
sectional designs (examining different children of different
ages), through longitudinal designs (examining the same chil-
dren at different ages), or through microgenetic designs (pre-
senting the same children repeated relevant experiences over
a relatively short period and analyzing the change process in
detail).
n It is vital for researchers to adhere to high ethical standards.
Among the most important ethical principles are striving to
ensure that the research does not harm children physically or
psychologically; obtaining informed consent from parents and,
where possible, from children; preserving participants’ ano-
nymity; and correcting any inaccurate impressions that chil-
dren form during the study.
Critical Thinking Questions
1. Do children have different natures, or are differences among
children purely due to differences in their experiences? What
personal observations, research findings, and reasoning lead
to your conclusion?
2. Why do you think that the children who spent less than 6
months in orphanages in Romania were able to catch up
physically, intellectually, and socially, whereas those who
spent more time there have not been able to catch up? Do
you think that they will catch up in the future?
3. In what ways is it fortunate and in what ways unfortunate that
children shape their own development to a substantial extent?
4. Did reading about sleeping arrangements in the United
States and in other cultures influence what you would like to
do if you have children? Explain why or why not.
5. Given what you learned in this chapter about child-
development research, can you think of practical applications
of the research (other than the ones described) that seem
both feasible and important to you?
Key Terms
clinical interview, p. 25
cognitive development, p. 15
continuous development, p. 13
control group, p. 31
correlation, p. 29
correlational designs, p. 28
counting-on strategy, p. 34
cross-sectional design, p. 32
dependent variable, p. 31
direction-of-causation problem, p. 29
discontinuous development, p. 13
epigenetics, p. 11
experimental control, p. 31
experimental designs, p. 30
experimental group, p. 31
external validity, p. 24
genome, p. 11
hypotheses, p. 23
independent variable, p. 31
internal validity, p. 24
interrater reliability, p. 24
longitudinal design, p. 33
methylation, p. 12
microgenetic design, p. 33
naturalistic observation, p. 26
nature, p. 10
neurotransmitters, p. 17
nurture, p. 11
random assignment, p. 30
reliability, p. 24
scientific method, p. 23
sociocultural context, p. 17
socioeconomic status (SES), p. 19
stage theories, p. 15
structured interview, p. 25
structured observation, p. 27
test–retest reliability, p. 24
third-variable problem, p. 29
validity, p. 24
variables, p. 28

38
Mother and Child
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Prenatal Development
and the Newborn Period
n Prenatal Development
Box 2.1: A Closer Look Beng Beginnings
Conception
Box 2.2: Individual Differences The First—and Last—
Sex Differences
Developmental Processes
Box 2.3: A Closer Look Phylogenetic Continuity
Early Development
An Illustrated Summary of Prenatal Development
Fetal Behavior
Fetal Experience
Fetal Learning
Hazards to Prenatal Development
Box 2.4: Applications Face Up to Wake Up
Review
n The Birth Experience
Diversity of Childbirth Practices
Review
n The Newborn Infant
State of Arousal
Negative Outcomes at Birth
Box 2.5: Applications Parenting a Low-Birth-Weight
Baby
Review
n Chapter Summary
chapter 2:

40
P
icture the following scenario: a developmental psychologist is investigat­
ing a very young research participant’s perceptual capacities and ability to
learn from experience. First, she plays a loud sound near the participant’s
ear. She notes that the participant moves vigorously in response and con­
cludes that the participant can hear the sound. Now she continues to play
the same tone, over and over. As everyone else in the lab gets tired of repeatedly
hearing the same sound, so, apparently, does the participant, who responds less and
less to the repetitions of the sound and eventually does not react to it at all. Has
the participant learned to recognize the sound, or just gone to sleep? To find out,
the researcher next presents a different sound, to which the participant responds
vigorously. The participant seems to have recognized a difference between the new
sound and the old one, suggesting that the participant has experienced some simple
learning. Wanting to see if the participant can learn something more complex, and
in a natural setting, the researcher sends the participant home, asking the partici­
pant’s mother to read aloud from a Dr. Seuss book for several minutes each day for
six weeks. The idea is to see whether the participant later shows any recognition of
the passages that were read. But before the researcher can test the participant again,
something quite important happens: the participant is born!
This scenario is not at all fanciful. Indeed, as you will discover later in this chap­
ter, it is an accurate description of a fascinating and informative study that helped
to revolutionize the scientific understanding of prenatal development (DeCasper
& Spence, 1986). As you will also discover in this chapter, researchers have been
asking many questions about the sensory and learning capabilities of fetuses. They
have been finding that while in the womb, fetuses can detect a range of stimuli
coming from the outside world, and that they can learn from these experiences and
be affected by them after birth.
In this chapter, we will examine the extraordinary course of prenatal develop­
ment—a time of astonishingly rapid and dramatic change. In addition to discussing
the normal processes involved in prenatal development, including fetal learning, we
will consider some of the ways in which these processes can be disrupted by en­
vironmental hazards. We will also examine the birth process and what the infant
experiences during this dramatic turning point, as well as some of the most salient
aspects of neonatal behavior. Finally, we will outline issues associated with prema­
ture birth.
In our discussion of the earliest periods of development, most of the themes
we described in Chapter 1 will play prominent roles. The most notable will be
nature and nurture, as we emphasize how every aspect of development before
birth results from the continual interplay of biological and environmental fac­
tors. The active child theme will also be featured, because the activity of the fetus
contributes in numerous vital ways to its development. In fact, as you will see,
normal prenatal development depends on certain fetal behaviors. Another theme
we will highlight is the sociocultural context of prenatal development and birth.
There is substantial cultural variation in how people think about the beginning
of life and how they handle the birth process. The theme of individual differences
comes into play at many points, starting with sex differences in survival rates
from conception on. The continuity/discontinuity theme is also prominent: despite
the dramatic contrast between prenatal and postnatal life, the behavior of new­
borns shows clear connections to their behavior and experience inside the womb.
Finally, the theme of research and children’s welfare is central to our discussion of
Themes
n Nature and Nurture
n The Active Child
n The Sociocultural Context
n Individual Differences
n Continuity/Discontinuity
n Research and Children’s
Welfare

P R E n A t A l D E v E l O P M E n t n 41
how poverty can affect prenatal development and birth outcomes, as well as to
our description of intervention programs designed to foster healthy development
for preterm infants.
Prenatal Development
Hidden from view, the process of prenatal development has always been mysteri­
ous and fascinating, and beliefs about the origins of human life and development
before birth have been an important part of the lore and traditions of all societies.
(Box 2.1 describes one set of cultural beliefs about the beginning of life that is quite
unlike those of Western societies.)
When we look back in history, we see great differences in how people have
thought about prenatal development. In the fourth century b.c.e., Aristotle posed
the fundamental question about prenatal development that was to underlie West­
ern thought about it for the next 15 centuries: Does prenatal life start with the
new individual already preformed, composed of a full set of tiny parts, or do the
many parts of the human body develop in succession? Aristotle rejected the idea
Few topics have generated more intense
debate and dispute in the United States
in recent years than the issue of when life
begins—at the moment of conception, the
moment of birth, or sometime in between.
The irony is that few who engage in this
debate recognize how complex the issue is
or the degree to which societies throughout
the world have different views on it.
Consider, for example, the perspective
of the Beng, a people in the Ivory Coast of
West Africa, who believe that every newborn
is a reincarnation of an ancestor (Gottlieb,
2004). According to the Beng, in the first
weeks after birth, the ancestor’s spirit, its
wru, is not fully committed to an earthly life
and therefore maintains a double existence,
traveling back and forth between the every-
day world and wrugbe, or “spirit village.”
(The term can be roughly translated as “af-
terlife,” but “before-life” might be just as
appropriate.) It is only after the umbilical
stump has dropped off that the newborn is
considered to have emerged from wrugbe
and to be a person. If the newborn dies be-
fore this point, there is no funeral, for the
infant’s passing is perceived as a return to
the wrugbe.
These beliefs underlie many aspects of
Beng infant-care practices. One is the fre-
quent application of an herbal mixture to the
newborn’s umbilical stump to hasten its dry-
ing out and dropping off. In addition, there is
the constant danger that the infant will be-
come homesick for its life in wrugbe and de-
cide to leave its earthly existence. To prevent
this, parents try to make their babies com-
fortable and happy so they will want to stay in
this life. Among the many recommended pro-
cedures is elaborately decorating the infant’s
face and body to elicit positive attention from
others. Sometimes diviners are consulted,
especially if the baby seems to be unhappy;
a common diagnosis for prolonged crying is
that the baby wants a different name—the
one from its previous life in wrugbe.
So when does life begin for the Beng? In
one sense, a Beng individual’s life begins
well before birth, since he or she is a rein-
carnation of an ancestor. In another sense,
however, life begins sometime after birth,
when the individual is considered to have
become a person.
BOX 2 .1: a closer look
BENG BEGINNINGS
The mother of this Beng baby has spent con-
siderable time painting the baby’s face in an
elaborate pattern. She does this every day in
an effort to make the baby attractive so other
people will help keep the baby happy in this
world.CO
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42 n chapTer 2 PREnAtAl DEvElOPMEnt AnD thE nEwBORn PERIOD
of preformation in favor of what he termed epigenesis—the emergence of new
structures and functions during development (we will revisit this idea in Chapter
3 in its more modern form, epigenetics). Seeking support for his idea, he took what
was then a very unorthodox step: he opened fertile chicken eggs to observe chick
organs in various stages of development. Nevertheless, the idea of preformation
persisted long after Aristotle, degenerating into a dispute about whether the mini­
ature, preformed human was lodged inside the mother’s egg or the father’s sperm
(see Figure 2.1).
The notion of preformation may strike you as simpleminded. Remember, how­
ever, that our ancient forebears had no way of knowing about the existence of cells
and genes or about behavioral development in the womb. Many of the mysteries
that perplexed our ancestors have now been solved, but as is always true in science,
new mysteries have replaced them.
Conception
Each of us originated as a single cell that resulted from the union of two highly
specialized cells—a sperm from our father and an egg from our mother. These
gametes, or germ cells, are unique not only in their function but also in the fact
that each one contains only half the genetic material found in other cells. Gametes
are produced through meiosis, a special type of cell division in which the eggs and
sperm receive only one member from each of the 23 chromosome pairs contained
in all other cells of the body. This reduction to 23 chromosomes in each gamete is
necessary for reproduction, because the union of egg and sperm must contain the
normal amount of genetic material (23 pairs of chromosomes). A major difference
in the formation of these two types of gametes is the fact that almost all the eggs
a woman will ever have are formed during her own prenatal development, whereas
men produce vast numbers of new sperm continuously.
The process of reproduction starts with the launching of an egg (the largest cell
in the human body) from one of the woman’s ovaries into the adjoining fallopian
tube (see Figure 2.2). As the egg moves through the tube toward the uterus, it emits
a chemical substance that acts as a sort of beacon, a “come­hither” signal that at­
tracts sperm toward it. If an act of sexual intercourse takes place near the time the
egg is released, conception, the union of sperm and egg, will be possible. In every
ejaculation, as many as 500 million sperm are pumped into the woman’s vagina.
Each sperm, a streamlined vehicle for delivering the man’s genes to the woman’s
egg, consists of little more than a pointed head packed full of genetic material (the
23 chromosomes) and a long tail that whips around to propel the sperm through
the woman’s reproductive system.
To be a candidate for initiating conception, a sperm must travel for about
6 hours, journeying 6 to 7 inches from the vagina up through the uterus to the
egg­bearing fallopian tube. The rate of attrition on this journey is enormous: of
FIGURE 2.1 preformationism a seventeenth-century drawing of a preformed being
inside a sperm. This drawing was based on the claim of committed preformationists that
when they looked at samples of semen under the newly invented microscope, they could
actually see a tiny figure curled up inside the head of the sperm. They believed that the
miniature person would enlarge after entering an egg. as this drawing illustrates, we must
always take care not to let our cherished preconceptions so dominate our thinking that we
see what we want to see—not what is really there. (From Moore & persaud, 1993, p. 7)
epigenesis n the emergence of new
structures and functions in the course of
development
gametes (germ cells) n reproductive
cells—egg and sperm—that contain only
half the genetic material of all the other
cells in the body
meiosis n cell division that produces
gametes
conception n the union of an egg from
the mother and a sperm from the father
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Placenta
Cervix
Vagina
Siegler, How Children Develop, 1e
Figure 2.3
Permanent #203
File name = 6101_Fig2.03! (Adobe Illustrator v8)
Placed eps file 6101_Fig2.03placed.eps (Adobe Photoshop v6)
Illustration by Todd Buck
Umbilical cord
Amniotic fluid
Fallopian tube
Ovary Fetus
Amnion
Chorion
FIGURE 2.2 Female reproductive system a simplified
illustration of the female reproductive system, with a fetus
developing in the uterus (womb). The umbilical cord runs from
the fetus to the placenta, which is burrowed deeply into the
wall of the uterus. The fetus is floating in amniotic fluid inside
the amniotic sac.
FIGURE 2.3 (a) Sperm nearing the egg
Of the millions of sperm that started out
together, only a few ever get near the egg.
The egg is the largest human cell (the only
one visible to the naked eye), but sperm are
among the smallest. (b) Sperm penetrating
the egg This sperm is whipping its tail
around furiously to drill itself through the
outer covering of the egg.
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(b)
the millions of sperm that enter the vagina, only about 200 ever get near the egg
(see Figure 2.3). There are many causes for this high failure rate. Some failures are
due to chance: many of the sperm get tangled up with other sperm milling about
in the vagina; others wind up in the fallopian tube that does not currently harbor
an egg. Other failures have to do with the fact that a substantial portion of the
sperm have serious genetic or other defects that prevent them from propelling
themselves vigorously enough to reach and fertilize the egg. Thus, any sperm that
do get to the egg are relatively likely to be healthy and structurally sound, revealing
a Darwinian­type “survival of the fittest” process operating during fertilization.
(Box 2.2 describes the consequences of this selection process for the conception
of males and females.)

44 n chapTer 2 PREnAtAl DEvElOPMEnt AnD thE nEwBORn PERIOD
As soon as one sperm’s head penetrates the outer membrane of the egg, a chemi­
cal reaction seals the membrane, preventing other sperm from entering. The tail
of the sperm falls off, the contents of its head gush into the egg, and the nuclei of
the two cells merge within hours. The fertilized egg, known as a zygote, now has
a full complement of human genetic material, half from the mother and half from
the father. The first of the three periods of prenatal development (see Table 2.1)
has begun and, if everything proceeds normally, that development will continue for
approximately 9 months (on average, 38 weeks or 266 days).
The proverbial competition between the
sexes might be said to begin with millions of
sperm racing to fertilize the egg. Sperm that
carry a Y chromosome (the genetic basis for
maleness) are lighter and swim faster than
those bearing an X chromosome, so the race
to the egg is won much more often by the
“boys.” As a result, approximately 120 to
150 males are conceived for every 100
females.
The girls win the next big competition—
survival. The ratio at birth is only 106
males to 100 females. Where are the miss-
ing males? Obviously, they are miscarried at
a much greater rate than females. Birth is
also more challenging for boys, who, usually
because of possible birth complications, are
50% more likely to need to be surgically re-
moved from the womb by means of a cesar-
ean delivery. This heightened vulnerability is
not limited to surviving the prenatal period.
Boys also suffer disproportionately from most
developmental disorders, including language
and learning disorders, dyslexia, attention-
deficit disorder, intellectual disabilities, and
autism. The greater fragility of males contin-
ues throughout life, as reflected in the graph.
Adolescent boys are more impulsive and take
more risks than girls, and they are more likely
to commit suicide or die violently.
Differential survival is not always left in
the hands of nature. In many societies, both
historically and currently, male offspring
are more highly valued than females, and
parents resort to infanticide to avoid hav-
ing daughters. For example, Inuit families
in Alaska traditionally depended on male
children to help in the hunt for food, and
in former times, Inuit girls were often killed
at birth. Over the past several decades,
the Chinese government strictly enforced a
“one-child” policy, a measure designed to
reduce population growth by forbidding cou-
ples to have more than one child. This policy
resulted in many parents killing or abandon-
ing their female babies (or giving them up
for adoption to Western families) in order to
make room for a male child. A more tech-
nological approach is currently practiced
in some countries that place a premium on
male offspring: prenatal tests are used to de-
termine the gender of the fetus, and female
fetuses are selectively aborted. These cases
dramatically illustrate the socio cultural
model of development described in Chapter
1 (pages 17–18), showing how cultural val-
ues, government policy, and available tech-
nology all affect developmental outcomes.
BOX 2 .2: individual differences
THE FIRST—AND LAST—SEX DIFFERENCES
Beginning at birth, the U.S. male-to-female
mortality ratio exceeds 1 across the life
span. The spike that occurs in adolescence
and early adulthood—peaking at 3 male
deaths for every female death—is largely the
result of external causes, such as accidents,
homicide, and suicide.
zygote n a fertilized egg cell
10
Age
20 30 40 50 60 70 80
1.5
2
2.5
3
3.5
4
4.5
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15 754535 6555250501
All Causes
External Causes
Internal Causes

P R E n A t A l D E v E l O P M E n t n 45
Developmental Processes
Before describing the course of prenatal development, we need to briefly out­
line four major developmental processes that underlie the transformation of a zy­
gote into an embryo and then a fetus. The first is cell division, known as mitosis.
Within 12 hours or so after fertilization, the zygote divides into two equal parts,
each containing a full complement of genetic material. These two cells then divide
into four, those four into eight, those eight into sixteen, and so on. Through con­
tinued cell division over the course of 38 weeks, the barely visible zygote becomes
a newborn consisting of trillions of cells.
A second major process, which occurs during the embryonic period, is cell migra-
tion, the movement of newly formed cells away from their point of origin. Among
the many cells that migrate are the neurons that originate deep inside the embry­
onic brain and then, like pioneers settling new territory, travel to the outer reaches
of the developing brain.
The third process in prenatal development is cell differentiation. Initially, all of
the embryo’s cells, referred to as embryonic stem cells, are equivalent and in­
terchangeable: none has any fixed fate or function. After several cell divisions,
however, these cells start to specialize in terms of both structure and function. In
humans, embryonic stem cells develop into roughly 350 different types of cells,
which perform particular functions on behalf of the organism. (Because of their de­
velopmental flexibility, embryonic stem cells are currently the focus of a great deal
of research in regenerative medicine. The hope is that when injected into a person
suffering from illness or injury, embryonic stem cells will develop into healthy cells
to replace the diseased or damaged ones.)
The process of differentiation is one of the major mysteries of prenatal develop­
ment. Since all cells in the body have the identical set of genes, what factors deter­
mine which type of cell a given stem cell will become? One key determinant is which
genes in the cell are “switched on” or expressed (see Box 2.3). Another is the cell’s
location, because its future development is influenced by what is going on in neigh­
boring cells.
The initial flexibility and subsequent inflexibility of cells, as well as the importance
of location, is vividly illustrated by classic research with frog embryos. If the region
of a frog embryo that would normally become an eye is grafted onto its belly area
early in fetal development, the transplanted region will develop as a normal part of
the belly. Thus, although the cells were initially in the right place to become an eye,
they had not yet become specialized. If the transplant is performed later in fetal de­
velopment, the same operation results in an eye—alone and unseeing—lodged in the
frog’s belly (Wolpert, 1991).
TABLE 2.1
periods of prenatal Development
Conception
to 2 weeks
Germinal Begins with conception and lasts until the zygote becomes
implanted in the uterine wall. Rapid cell division takes place.
3rd to 8th week Embryonic Following implantation, major development occurs in all the organs
and systems of the body. Development takes place through the
processes of cell division, cell migration, cell differentiation, and
cell death, as well as hormonal influences.
9th week to birth Fetal Continued development of physical structures and rapid growth of the
body. Increasing levels of behavior, sensory experience, and learning.
embryo n the name given to the devel-
oping organism from the 3rd to 8th week
of prenatal development
fetus n the name given to the developing
organism from the 9th week to birth
mitosis n cell division that results in two
identical daughter cells
embryonic stem cells n embryonic
cells, which can develop into any type of
body cell

46 n chapTer 2 PREnAtAl DEvElOPMEnt AnD thE nEwBORn PERIOD
BOX 2 .3: a closer look
PHYLOGENETIC CONTINUITY
Throughout this book, we will use research
with nonhuman animals to make points
about human development. In doing so, we
subscribe to the principle of phylogenetic
continuity—the idea that because of our
common evolutionary history, humans share
many characteristics and developmental
processes with other living things. Indeed,
you share most of your genes with your dog,
cat, or hamster.
The assumption that animal models of
behavior and development can be useful
and informative for human development
underlies a great deal of research. For ex-
ample, much of our knowledge about the
dangers of alcohol consumption by pregnant
women comes from research with nonhu-
man animals. Because scientists suspected
that drinking alcohol while pregnant caused
the constellation of defects now known as
fetal alcohol spectrum disorder (page 62),
they experimentally exposed fetal mice to
alcohol. At birth, these mice had atypical
facial features, remarkably similar to the
facial anomalies of human children heav-
ily exposed to alcohol in the womb by their
mother. This fact increased researchers’
confidence that the problems commonly as-
sociated with fetal alcohol syndrome are, in
fact, caused by alcohol rather than by some
other factor.
One of the most fascinating discoveries
in recent years, discussed later in this chap-
ter, is the existence of fetal learning. This
phenomenon was first documented in one
of comparative psychologists’ favorite crea-
tures—the rat. To survive after birth, new-
borns must find a milk-producing maternal
nipple. How do they know where to go? The
answer is that they search for something fa-
miliar to them. During the birth process, the
nipples on the underside of the mother rat’s
belly get smeared with amniotic fluid. The
scent of the amniotic fluid is familiar to the
rat pups from their time in the womb, and it
lures the babies to where they need to be—
with their noses, and hence their mouths,
near a nipple (Blass, 1990).
How was it determined that newborn rats
find their mother’s nipple by recognizing the
scent of amniotic fluid? For one thing, when
researchers washed the mother’s belly clean
of amniotic fluid, her pups failed to find her
nipples, and if half her nipples were washed,
the pups were attracted to the unwashed
ones with amniotic fluid still on them (Blass
& Teicher, 1980). Even more impressive,
when researchers introduced odors or flavors
into the amniotic fluid, either by directly in-
jecting them or by adding them to the moth-
er’s diet, her pups preferred those odors and
tastes after birth (Hepper, 1988; Pedersen
& Blass, 1982; Smotherman & Robinson,
1987). These and other demonstrations of
fetal learning in rodents inspired develop-
mental psychologists to look for similar pro-
cesses in human fetuses. As you will see
later, they found them.
Scientists interested in human development have learned a great deal by
studying maternal behavior in rats.
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FIGURE 2.4 embryonic
hand plate Fingers will
emerge from the hand plate
of this 7-week-old embryo.
The fingers are formed as a
result of the death of the cells
between the ridges you can
see in the plate. If these cells
did not expire, the baby would
be born with webbed rather
than independent fingers.
The fourth developmental process is something
you would not normally think of as developmental
at all—death. However, the selective death of certain
cells is the “almost constant companion” to the other
developmental processes we have described (Wolpert,
1991). The role of this genetically programmed “cell
suicide,” known as apoptosis, is readily apparent in
hand development (see Figure 2.4): the formation of
fingers depends on the death of the cells in between lEn
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the ridges in the hand plate. In other words, death is preprogrammed for the cells
that disappear from the hand plates.
In addition to these four developmental processes, we need to call attention to
the influence of hormones on prenatal development. For example, hormones play
a crucial role in sexual differentiation. All human fetuses, regardless of the genes
they carry, can develop either male or female genitalia. The presence or absence of
androgens, a class of hormones that includes testosterone, causes development to
proceed one way or the other. If androgens are present, male sex organs develop;
if they are absent, female genitalia develop. The source of androgens is the male
fetus itself. Around the 8th week after conception, the testes begin to produce these
hormones, changing the developing organism forever. This is just one of the many
ways in which the fetus influences its own development.
We now turn our attention to the general course of prenatal development that
results from all the preceding influences, as well as other developmental processes.
Early Development
On its journey through the fallopian tube to the womb, the zygote doubles its
number of cells roughly twice a day. By the 4th day after conception, the cells ar­
range themselves into a hollow sphere with a bulge of cells, called the inner cell
mass, on one side.
This is the stage at which identical twins most often originate. They result
from a splitting in half of the inner cell mass, and thus they both have exactly
the same genetic makeup. In contrast, fraternal twins result when two eggs hap­
pen to be released from the ovary into the fallopian tube and both are fertilized.
Because they originate from two different eggs and two different sperm, fra­
ternal twins are no more alike genetically than nontwin siblings with the same
parents.
By the end of the 1st week following fertilization, if all goes well (which it does
for less than half the zygotes that are conceived), a momentous event occurs—
implantation, in which the zygote embeds itself in the uterine lining and becomes
dependent on the mother for sustenance. Well before the end of the 2nd week, it
will be completely embedded within the uterine wall.
After implantation, the embedded ball of cells starts to differenti­
ate. The inner cell mass becomes the embryo, and the rest of the cells
become an elaborate support system—including the amniotic sac and
placenta—that enables the embryo to develop. The inner cell mass is
initially a single layer thick, but during the 2nd week, it folds itself into
three layers, each with a different developmental destiny. The top layer
becomes the nervous system, the nails, teeth, inner ear, lens of the eyes,
and the outer surface of the skin. The middle layer eventually becomes
muscles, bones, the circulatory system, the inner layers of the skin, and
other internal organs. The bottom layer develops into the digestive sys­
tem, lungs, urinary tract, and glands. A few days after the embryo has
differentiated into these three layers, a U­shaped groove forms down the
center of the top layer. The folds at the top of the groove move together
and fuse, creating the neural tube (Figure 2.5). One end of the neural
tube will swell and develop into the brain, and the rest will become the
spinal cord.
The support system that is emerging along with the embryo is elabo­
rate and essential to the embryo’s development. One key element of this
phylogenetic continuity n the idea
that because of our common evolutionary
history, humans share many characteris-
tics, behaviors, and developmental pro-
cesses with other animals, especially
mammals
apoptosis n genetically programmed cell
death
identical twins n twins that result
from the splitting in half of the zygote,
resulting in each of the two resulting
zygotes having exactly the same set of
genes
fraternal twins n twins that result
when two eggs happen to be released into
the fallopian tube at the same time and
are fertilized by two different sperm; fra-
ternal twins have only half their genes in
common.
neural tube n a groove formed in the
top layer of differentiated cells in the
embryo that eventually becomes the brain
and spinal cord
FIGURE 2.5 Neural tube In the 4th
week, the neural tube begins to develop into
the brain and spinal cord. In this photo, the
neural groove, which fuses together first at
the center and then outward in both direc-
tions as if two zippers were being closed,
has been “zipped shut” except for one part
still open at the top. Spina bifida, a con-
genital disorder in which the skin over the
spinal cord is not fully closed, can originate
at this point. after closing, the top of the
neural tube will develop into the brain.
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48 n chapTer 2 PREnAtAl DEvElOPMEnt AnD thE nEwBORn PERIOD
support system is the amniotic sac, a membrane filled with a clear, watery fluid
in which the fetus floats. The amniotic fluid operates as a protective buffer for the
developing fetus, providing it with a relatively even temperature and cushioning it
against jolting. As you will see shortly, because the amniotic fluid keeps the fetus
afloat, the fetus can exercise its tiny, weak muscles relatively unhampered by the
effects of gravity.
The second key element of the support system, the placenta, is a unique organ
that permits the exchange of materials carried in the bloodstreams of the fetus and
its mother. It is an extraordinarily rich network of blood vessels, including minute
ones extending into the tissues of the mother’s uterus, with a total surface area of
about 10 square yards—approximately the amount of driveway covered by the fam­
ily car (Vaughan, 1996). Blood vessels running from the placenta to the embryo
and back again are contained in the umbilical cord.
At the placenta, the blood systems of the mother and fetus come extremely close
to each other, but the placenta prevents their blood from actually mixing. However,
the placental membrane is semipermeable, meaning that some elements can pass
through it but others cannot. Oxygen, nutrients, minerals, and some antibodies—
all of which are just as vital to the fetus as they are to you—are transported to the
placenta by the mother’s circulating blood. They then cross the placenta and enter
the fetal blood system. Waste products (e.g., carbon dioxide, urea) from the fetus
cross the placenta in the opposite direction and are removed from the mother’s
bloodstream by her normal excretory processes.
The placental membrane also serves as a defensive barrier against a host of dan­
gerous toxins and infectious agents that can inhabit the mother’s body and could be
harmful or even fatal to the fetus. Unfortunately, being semipermeable, the placenta
is not a perfect barrier, and, as you will see later, a variety of harmful elements can
cross it and attack the fetus. One other function of the placenta is the production
of hormones, including estrogen, which increases the flow of maternal blood to the
uterus, and progesterone, which suppresses uterine contractions that could lead to
premature birth (Nathanielsz, 1994).
An Illustrated Summary of Prenatal Development
The course of prenatal development from the 4th week on is illustrated in Figures
2.6 through 2.13, and significant milestones are highlighted in the accompanying
text. (The fetal behaviors that are mentioned will be discussed in detail in the fol­
lowing section.) Notice that earlier development takes place at a more rapid pace
than later development, and that the areas nearer the head develop earlier than
those farther away (e.g., head before body, hands before feet)—a general tendency
known as cephalocaudal development.
Figure 2.6: At 4 weeks after conception, the embryo is curved so tightly that
the head and the tail­like structure at the other end are almost touching. Several
facial features have their origin in the set of four folds in the front of the embryo’s
head; the face gradually emerges as a result of these tissues moving and stretching,
as parts of them fuse and others separate. The round area near the top of the head
is where the eye will form, and the round gray area near the back of the “neck” is
the primordial inner ear. A primitive heart is visible; it is already beating and cir­
culating blood. An arm bud can be seen in the side of the embryo; a leg bud is also
present but less distinct.
Figure 2.7: (a) In this 5½­week­old fetus, the nose, mouth, and palate are be­
ginning to differentiate into separate structures. (b) Just 3 weeks later, the nose
amniotic sac n a transparent, fluid-
filled membrane that surrounds and pro-
tects the fetus
placenta n a support organ for the
fetus; it keeps the circulatory systems
of the fetus and mother separate, but
as a semipermeable membrane permits
the exchange of some materials between
them (oxygen and nutrients from mother
to fetus and carbon dioxide and waste
products from fetus to mother)
umbilical cord n a tube containing the
blood vessels connecting the fetus and
placenta
cephalocaudal development n the
pattern of growth in which areas near the
head develop earlier than areas farther
from the head
FIGURE 2.6 embryo at 4 weeks
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P R E n A t A l D E v E l O P M E n t n 49
and mouth are almost fully formed. Cleft pal­
ate, one of the most common birth defects
worldwide, involves malformations (some­
times minor, sometimes major) of this area.
This condition originates sometime between
5½ and 8 weeks prenatally— precisely when
these structures are developing.
Figure 2.8: The head of this 9­week­
old fetus overwhelms the rest of its body.
The bulging forehead reflects the extremely
rapid brain growth that has been going on
for weeks. Rudimentary eyes and ears are
forming. All the internal organs are pres­
ent, although most must undergo further
development. Sexual differentiation has
started. Ribs are visible, fingers and toes have
emerged, and nails are growing. You can see
the umbilical cord connecting the fetus to the placenta. The fetus makes sponta­
neous movements, but because it is so small and is floating in amniotic fluid, the
mother cannot feel them.
Figure 2.9: This image of an 11­week­old fetus clearly shows the heart, which
has achieved its basic adult structure. You can also see the developing spine and
ribs, as well as the major divisions of the brain.
Figure 2.10: During the last 5 months of prenatal development, the growth
of the lower part of the body accelerates. The fetus’s movements have increased
dramatically: its chest makes breathing movements, and some reflexes—grasping,
(a)
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FIGURE 2.7 Face development from 5½
to 8½ weeks
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FIGURE 2.8 Fetus at 9 weeks
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FIGURE 2.9 Fetus at 11 weeks
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50 n chapTer 2 PREnAtAl DEvElOPMEnt AnD thE nEwBORn PERIOD
swallowing, sucking—are present. By 16 weeks,
the fetus is capable of intense kicks, although the
mother feels them only as a mild “flutter.” At this
age, the external genitalia are substantially devel­
oped, and a different camera angle would have re­
vealed whether this fetus is male or female.
Figure 2.11: This 18­week­old fetus is clearly
sucking its thumb, in much the same way it will as
a newborn. The fetus is covered with very fine hair,
and a greasy coating protects its skin from its long
immersion in liquid.
Figure 2.12: By the 20th week, the fetus spends
increasingly more time in a head­down position. The
components of facial expressions are present—the
fetus can raise its eyebrows, wrinkle its forehead, and
move its mouth. As the fetus rapidly puts on weight,
the amniotic sac becomes more cramped, leading to
a decrease in fetal movements.
Figure 2.13: The 28th week marks the point at
which the brain and lungs are sufficiently developed
that a fetus born at this time would have a chance of
surviving on its own, without medical intervention.
The eyes can open, and they move, especially during
periods of rapid eye movement (REM) sleep. The
auditory system is now functioning, and the fetus
hears and reacts to a variety of sounds. At this stage
of development, the neural activity of the fetus is
very similar to that of a newborn. During the last 3
FIGURE 2.10 Fetus at 16 weeks
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FIGURE 2.12 Fetus at 20 weeks
FIGURE 2.11 Fetus at 18 weeks
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P R E n A t A l D E v E l O P M E n t n 51
months of prenatal development, the fetus grows dramatically in size, essentially
tripling its weight.
The typical result of this 9­month period of rapid and remarkable development
is a healthy newborn.
Fetal Behavior
As we have noted, the fetus is an active participant in, and contributor to, its own
physical and behavioral development. Indeed, the normal formation of organs and
muscles depends on fetal activity, and the fetus rehearses the behavioral repertoire
it will need at birth.
Movement
Few mothers realize how early their child started moving in the womb. From 5 or
6 weeks after conception, the fetus moves spontaneously, starting with a simple
bending of the head and spine that is followed by the onset of increasingly complex
movements over the next weeks (De Vries, Visser, & Prechtl, 1982). One of the
earliest distinct patterns of movement to emerge (at around 7 weeks) is, remark­
ably enough, hiccups. Although the reasons for prenatal hiccups are unknown, one
recent theory posits that they are essentially a burping reflex, preparing the fetus
for eventual nursing by removing air from the stomach and making more room for
milk (Howes, 2012).
The fetus also moves its limbs, wiggles its fingers, grasps the umbilical cord,
moves its head and eyes, and yawns. Complete changes of position are achieved
by a kind of backward somersault. These various movements are initially jerky and
uncoordinated but gradually become more integrated. By 12 weeks, most of the
movements that will be present at birth have appeared (De Vries et al., 1982),
although the mother is still unaware of them.
Later on, when mothers can readily feel the movement of their fetuses, their re­
ports reveal that how much a fetus moves is quite consistent over time: some fetuses
are usually very active, whereas others are more sedentary (Eaton & Saudino, 1992).
This prenatal continuity extends into the postnatal period: more active fetuses turn
FIGURE 2.13 Fetus at 28 weeks
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52 n chapTer 2 PREnAtAl DEvElOPMEnt AnD thE nEwBORn PERIOD
out to be more active infants (DiPietro et al., 1998). Further­
more, fetuses that have regular periods of sleep and waking are
more likely to have regular sleep times as newborns (DiPietro,
Bornstein et al., 2002).
A particularly important form of fetal movement is swallow-
ing. The fetus drinks amniotic fluid, which passes through its
gastrointestinal system. Most of the fluid is then excreted back
out into the amniotic sac. One benefit of this activity is that the
tongue movements associated with drinking and swallowing pro­
mote the normal development of the palate (Walker & Quarles,
1976). In addition, the passage of amniotic fluid through the
digestive system helps it to mature properly. Thus, swallowing
amniotic fluid prepares the fetus for survival outside the womb.
A second form of fetal movement anticipates the fact that at
birth the newborn must start breathing. For that to happen, the
lungs and the rest of the respiratory system, including the muscles that move the
diaphragm in and out, must be mature and functional. Beginning as early as 10
weeks after conception, the fetus promotes its respiratory readiness by exercising
its lungs through “fetal breathing,” moving its chest wall in and out (Nathanielsz,
1994). No air is taken in, of course; rather, small amounts of amniotic fluid are
pulled into the lungs and then expelled. Unlike real breathing, which involves an
ongoing and consistent pattern of lung activity, fetal breathing is initially infrequent
and irregular, but it increases in rate and stability, especially over the third trimester
(Govindan et al., 2007).
Behavioral Cycles
Once the fetus begins to move at 5 to 6 weeks, it is in almost constant motion for
the next month or so. Then periods of inactivity gradually begin to occur. Rest–
activity cycles—bursts of high activity alternating with little or no activity for a few
minutes at a time—emerge as early as 10 weeks and become very stable during the
second half of pregnancy (Robertson, 1990). In the latter half of the prenatal pe­
riod, the fetus moves only about 10% to 30% of the time (DiPietro et al., 1998).
Longer­term patterns, including daily (circadian) rhythms, also become appar­
ent, with less activity in the early morning and more activity in the late evening
(Arduini, Rizzo, & Romanini, 1995). This confirms the impression of most preg­
nant women that their fetuses wake up and start doing acrobatics just as they them­
selves are trying to go to sleep.
Near the end of pregnancy, the fetus spends more than three­fourths of its time
in quiet and active sleep states like those of the newborn ( James et al., 1995) (see
page 70). The active sleep state is characterized by REM, just as it is in infants
and adults.
Fetal Experience
There is a popular idea—promoted by everyone from scholars to cartoonists—that
we spend our lives longing for the tranquil sanctuary we experienced in our moth­
er’s womb. But is the womb a haven of peace and quiet? Although the uterus and
the amniotic fluid buffer the fetus from much of the stimulation impinging on the
mother, research has made it clear that the fetus experiences an abundance of sen­
sory stimulation.
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“It’s a baby. Federal regulations prohibit our
mentioning its race, age, or gender.”
Developmental psychologist Janet Dipietro
is using ultrasound to study the movement
patterns of this woman’s fetus.
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P R E n A t A l D E v E l O P M E n t n 53
Sight and Touch
Although it is not totally dark inside the womb, the visual experience of the fetus
is minimal. The fetus does, however, experience tactile stimulation as a result of
its own activity. In the course of moving around, its hands come into contact with
other parts of its body: fetuses have been observed not only grasping their umbilical
cords but also rubbing their face and sucking their thumbs (Figure 2.11). Indeed,
the majority of fetal arm movements during the second half of pregnancy result in
contact between their hand and mouth (Myowa­Yamakoshi & Takeshita, 2006). As
the fetus grows larger, it bumps against the walls of the uterus increasingly often.
By full term, fetuses respond to maternal movements (repeated rocking and sway­
ing), suggesting that their vestibular systems—the sensory apparatus in the inner
ear that provides information about movement and balance—is also functioning
before birth (Lecanuet & Jacquet, 2002).
Taste
The amniotic fluid contains a variety of flavors (Maurer & Maurer, 1988). The
fetus can detect these flavors, and likes some better than others. Indeed, the fetus
has a sweet tooth. The first evidence of fetal taste preferences came from a medi­
cal study performed more than 60 years ago (described by Gandelman, 1992). A
physician named DeSnoo devised an ingenious treatment for women with exces­
sive amounts of amniotic fluid. He injected saccharin into their amniotic fluid,
hoping that the fetus would help the mother out by ingesting increased amounts
of the sweetened fluid, thereby diminishing the excess. And, in fact, tests of the
mothers’ urine showed that the fetuses ingested more amniotic fluid when it had
been sweetened, demonstrating that taste sensitivity and flavor preferences exist
before birth.
Smell
Amniotic fluid takes on odors from what the mother has eaten (Mennella, Johnson,
& Beauchamp, 1995). Obstetricians have long reported that during birth they
can smell scents like curry and coffee in the amniotic fluid of women who had re­
cently consumed them. Indeed, human amniotic fluid has been shown to be rich in
odorants (although many do not sound very appealing—including those described
as being pungently rancid, goaty, or having a “strong fecal note”; Schaal, Orgeur,
& Rognon, 1995). Smells can be transmitted through liquid, and amniotic fluid
comes into contact with the fetus’s odor receptors through fetal breathing, provid­
ing fetuses with the opportunity for olfactory experience. Indeed, as discussed in
Box 2.3, rat pups use the familiar scent of their mother’s amniotic fluid to find their
mother’s nipples after birth.
Hearing
Picture serious scientists hovering over a pregnant woman’s bulging abdomen,
ringing bells, striking a gong, clapping blocks of wood together, and even sound­
ing an automobile horn—all to see if her fetus reacts to auditory stimulation.
(Remind you of the opening to this chapter?) Such research has demonstrated
that external sounds that are audible to the fetus include the voices of people
talking to the woman. In addition, the prenatal environment includes many
maternal sounds—the mother’s heartbeat, blood pumping through her vascu­
lar system, her breathing, her swallowing, and various rude noises made by her

54 n chapTer 2 PREnAtAl DEvElOPMEnt AnD thE nEwBORn PERIOD
digestive system. A particularly prominent and frequent source
of sound stimulation is the mother’s voice as she talks, with the
clearest aspects being the general rhythm and pitch patterns of
her speech.
The fetus responds to these various sounds from at least the 6th
month of pregnancy on. During the last trimester, external noises
elicit changes in fetal movements and heart rate (Kisilevsky, Fearon,
& Muir, 1998; Lecanuet et al., 1995; Zimmer et al., 1993). By the
time fetuses are at term, changes in heart rate patterns suggest that
they can distinguish between music and speech played near the
mother’s abdomen (Granier­Deferre et al., 2011). The fetus’s heart
rate also decelerates briefly when the mother starts speaking (Fifer
& Moon, 1995). (Transitory heart­rate deceleration is a sign of in­
terest.) The fetus’s extensive auditory experience with human voices
has some lasting effects, as we discuss in the next section.
Fetal Learning
To this point, we have emphasized the impressive behavioral and sensory capabilities
of the fetus in the early stages of development. Even more impressive is the extent
to which the fetus learns from many of its experiences in the
last 3 months of pregnancy, after the central nervous system is
adequately developed to support learning.
Direct evidence for human fetal learning comes from
studies of habituation, one of the simplest forms of learning
(Thompson & Spencer, 1966). Habituation involves a de­
crease in response to repeated or continued stimulation (see
Figure 2.14). If you shake a rattle beside an infant’s head, the
baby will likely turn toward it. At the same time, the infant’s
heart rate may slow momentarily, indicating interest. If you re­
peatedly shake the rattle, however, the head­turning and heart­
rate changes will decrease and eventually stop. This decreased
response is evidence of learning and memory: the stimulus loses
its novelty (and becomes boring) only if the infant remembers
the stimulus from one presentation to the next. When a new
stimulus occurs, the habituated response recovers (increases).
Shaking a bell, for example, may reinstate the head­turning
and heart­rate responses. (Developmental psychologists have
exploited habituation to study a great variety of topics that you will read about in
later chapters.) The earliest time at which fetal habituation has been observed is 30
weeks, indicating that the central nervous system is sufficiently developed at this
point for learning and short­term memory to occur (Dirix et al., 2009).
The mother’s voice is probably the most interesting sound frequently available
to fetuses. If fetuses can learn something about their mother’s voice prenatally, this
could provide them with a running start for learning about other aspects of speech
after birth. To test this idea, Kisilevsky and colleagues (2003) tested term fetuses in
one of two conditions. Half of the fetuses listened to a recording of their mother
reading a poem, played through speakers placed on their mother’s abdomen. The
other half listened to recordings of the same poem read by another woman. The
researchers found that fetal heart rate increased in response to the mother’s voice,
and decreased in response to the other woman’s voice. These findings suggest that
The fetus of this pregnant woman may be
“eavesdropping” on her conversation with
her friends.
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Recovery
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FIGURE 2.14 habituation habituation
occurs in response to the repeated presen-
tation of a stimulus. as the first stimulus is
repeated and becomes familiar, the response
to it gradually decreases. When a novel
stimulus occurs, the response recovers. The
decreased response to the repeated stimulus
indicates the formation of memory for it;
the increased response to the novel stim-
ulus indicates discrimination of it from the
familiar one, as well as a general preference
for novelty.
habituation n a simple form of learning
that involves a decrease in response to
repeated or continued stimulation

P R E n A t A l D E v E l O P M E n t n 55
the fetuses recognized (and were aroused by) the sound of their own mother’s voice
relative to a stranger’s voice. For this to be the case, fetuses must be learning and
remembering the sound of their mother’s voice.
After birth, do newborns remember anything about their fetal experience? The
answer is a resounding yes! Like the rat pups discussed in Box 2.3, newborn hu­
mans remember the scent of the amniotic fluid in which they lived prenatally. In
one set of studies, newborns were presented with two pads, one saturated with their
own amniotic fluid and the other saturated with the amniotic fluid of a different
baby. With the two pads located on either side of their head, the infants revealed a
preference for the scent of their own amniotic fluid by keeping their head oriented
longer toward that scent (Marlier, Schaal, & Soussignan, 1998; Varendi, Porter, &
Winberg, 2002). These findings extend to specific flavors ingested by the mother.
For example, infants whose mothers ate anise (licorice flavor) while they were preg­
nant preferred the scent of anise at birth, while infants whose mothers did not eat
anise showed either a neutral or negative response to its scent (Schaal, Marlier, &
Soussignan, 2000).
Experiences in the womb can lead to long­lasting taste preferences. In one study,
pregnant women were asked to drink carrot juice four days a week for three weeks
near the end of their pregnancy (Mennella, Jagnow, & Beauchamp, 2001). When
tested at around 5½ months of age, their babies reacted more positively to cereal
prepared with carrot juice than to the same cereal prepared with water. Thus, the
flavor preferences of these babies reflected the influence of their experience in the
womb several months earlier. This finding reveals a persistent effect of prenatal
learning. Furthermore, it may shed light on the origins and strength of cultural
food preferences. A child whose mother ate a lot of chili peppers, ginger, and cumin
during pregnancy, for example, might be more favorably disposed to Indian food
than would a child whose mother’s diet lacked those flavors.
Along with taste, newborns also remember sounds they heard in the womb. In
a classic study, DeCasper and Spence (1986) asked pregnant women to read aloud
twice a day from The Cat in the Hat (or another Dr. Seuss book) during the last 6
weeks of their pregnancy. Thus, the women’s fetuses were repeatedly exposed to the
same highly rhythmical pattern of speech sounds. The question was whether they
would recognize the familiar story after birth. To find out, the researchers tested
them as newborns. The infants were fitted with miniature headphones and given a
special pacifier to suck on (see Figure 2.15). When the infants sucked in one partic­
ular pattern, they heard the familiar story through the headphones, but when they
sucked in a different pattern, they heard an unfamiliar story. The babies quickly
increased their sucking in the pattern that enabled them to hear the familiar story.
Thus, these newborns apparently recognized and preferred the rhythmic patterns
from the story they had heard in the womb.
Newborns exhibit numerous additional auditory preferences based on prenatal
experience. To begin with, they prefer to listen to their own mother’s voice rather
than to the voice of another woman (DeCasper & Fifer, 1980). But how do re­
searchers know that this isn’t due to experience in the hours or days after birth? It
turns out that newborns prefer to listen to a version of their mother’s voice that has
been filtered to sound the way it did in the womb (Moon & Fifer, 1990; Spence
& Freeman, 1996). Finally, newborns would rather listen to the language they
heard in the womb than to another language (Mehler et al., 1988; Moon, Cooper,
& Fifer, 1993). Newborns whose mothers speak French prefer listening to French
over Russian, for example, and this preference is maintained when the speech is fil­
tered to sound the way it sounded in the womb.
FIGURE 2.15 prenatal learning This
newborn can control what he gets to listen
to. his pacifier is hooked up to a computer,
which is in turn connected to an audio
player. If the baby sucks in one pattern
(predetermined by the researchers), he will
hear one recording. If he sucks in a different
pattern, he will hear a different recording.
researchers have used this technique to
investigate many questions about infant
abilities, including the influence of fetal
experience on newborn preferences.
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56 n chapTer 2 PREnAtAl DEvElOPMEnt AnD thE nEwBORn PERIOD
There can be little question that the human fetus is listening and learning. Does
this mean that parents­to­be should sign up for programs that promise to “educate
your unborn child”? Such programs exhort the mother­to­be to talk to her fetus,
read books to it, play music through speakers attached to her abdomen, and so on.
Some also urge the father­to­be to speak through a megaphone aimed at his wife’s
bulging belly in the hope that the newborn will recognize his voice as well as the
mother’s. Is there any point in such exercises?
Probably not. Although it seems possible that hearing Dad’s voice more clearly
and more frequently might lead the newborn to prefer it over unfamiliar voices,
such a preference develops very quickly after birth anyway. And it is quite clear
that some of the advertised advantages of prenatal training would not occur. In
the first place, the fetal brain is unlikely to be sufficiently developed to be able to
process much about language meaning (after all, even newborn infants can’t learn
words). In addition, the liquid environment in the womb—provided by the am­
niotic fluid—filters out detailed speech sounds, leaving only pitch contours and
rhythmic patterns. Brain development aside, this acoustic environment, along with
the fetus’s lack of visual access to the external world, would make it impossible for
a fetus to learn the meaning of words or any kind of factual knowledge, no mat­
ter how much the mother­to­be might read aloud. In short, what the fetus learns
about is the mother’s voice and the general patterns of her language—not any spe­
cific content. We suspect that the current craze for “prenatal education” will go the
way of other ill­conceived attempts to shape early development to adult desires.
Hazards to Prenatal Development
Thus far, our focus has been on the normal course of development before birth.
Unfortunately, prenatal development is not always free of error or misfortune. The
most dire, and by far the most common, misfortune is spontaneous abortion—
commonly referred to as miscarriage. Most miscarriages occur before the woman
even knows that she is pregnant. For example, in a Chinese sample, Wang and col­
leagues (2003) found that approximately one­third of the fetuses did not survive to
birth, and that two­thirds of those miscarriages occurred before the pregnancy was
clinically detectable. The majority of embryos that are miscarried very early have
severe defects, such as a missing chromosome or an extra one, that make further
development impossible. In the United States, about 15% of clinically recognized
pregnancies end in miscarriage (Rai & Regan, 2006). Across their childbearing
years, at least 25% of women—and possibly as many as 50%—experience at least
one miscarriage. Few couples realize how common this experience is, making it all
the more painful if it happens to them. Yet more agonizing is the experience of the
approximately 1% of couples who experience recurrent miscarriages, or the loss of
three or more consecutive pregnancies (Rai & Regan, 2006).
For fetuses that survive the danger of miscarriage, there is still a range of fac­
tors that can lead to unforeseen negative consequences. Genetic factors, which are
the most common, will be discussed in the next chapter. Here, we consider some
of the many environmental influences that can have harmful effects on prenatal
development.
Environmental Influences
In the spring of 1956, two sisters were brought to a Japanese hospital, delirious and
unable to walk. Their parents and doctors were mystified by the sudden deteriora­
tion in the girls, described as having been “the brightest, most vibrant, cutest kids

P R E n A t A l D E v E l O P M E n t n 57
you could imagine.” The mystery intensified as more children and adults developed
nearly identical symptoms. The discovery that all the patients were from the small
coastal town of Minamata suggested a common cause for what was referred to as
the “strange disease” (Newland & Rasmussen, 2003; Smith & Smith, 1975).
That cause was eventually traced to the tons of mercury that had been dumped
into Minamata Bay by a local petrochemical and plastics factory. For years, the
residents of Minamata had been catching and consuming fish that had absorbed
mercury from the polluted waters of the bay. By 1993, more than 2000 children
and adults had been diagnosed with what had come to be known as “Minamata
disease”—methylmercury poisoning (Harada, 1995). At least 40 children had been
poisoned prenatally by mercury in the fish eaten by their pregnant mothers and
were born with cerebral palsy, intellectual disabilities, and a host of other neuro­
logical disorders.
The tragedy of Minamata Bay provided some of the first clear evidence of the
seriously detrimental impact that environmental factors can have on prenatal de­
velopment. As you will see, a vast array of environmental agents, called teratogens,
have the potential to harm the fetus. The resulting damage ranges from relatively
mild and easily corrected problems to fetal death.
A crucial factor in the severity of the effects of potential teratogens is timing
(one of the basic developmental principles discussed in Chapter 1). Many terato­
gens cause damage only if they are present during a sensitive period in prena­
tal development. The major organ systems are most vulnerable to damage at the
time when their basic structures are being formed. Because the timing is different
for each system, the sensitive periods are different for each system, as shown in
Figure 2.16.
There is no more dramatic or straightforward illustration of the importance of
timing than the birth outcomes related to the drug thalidomide in the early 1960s.
Thalidomide was prescribed to treat morning sickness (among other things), and
was considered to be so safe that it was sold over the counter. At the time, it was be­
lieved that such medications would not cross the placental barrier. However, many
Victims of “Minamata disease” include indi-
viduals who were exposed to methylmercury
prenatally.
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teratogen n an external agent that can
cause damage or death during prenatal
development
sensitive period n the period of time
during which a developing organism is
most sensitive to the effects of external
factors; prenatally, the sensitive period is
when the fetus is maximally sensitive to
the harmful effects of teratogens

58 n chapTer 2 PREnAtAl DEvElOPMEnt AnD thE nEwBORn PERIOD
pregnant women who took this new, presumably safe sedative gave birth to babies
with major limb deformities; some babies were born with no arms and with flip­
perlike hands growing out of their shoulders. In a striking illustration of sensitive
period effects, serious defects occurred only if the pregnant woman took the drug
between the 4th and 6th week after conception, the time when her fetus’s limbs
were emerging and developing (look again at Figures 2.6 to 2.13). Taking thalido­
mide either before the limbs started to develop or after they were basically formed
had no harmful effect.
As you can see in Figure 2.16, the sensitive periods for many organ systems—
and hence the time when the most significant teratogenic damage can result from
something the mother does or experiences—occur before the woman might real­
ize she is pregnant. Because a substantial number of pregnancies are unplanned,
Central nervous system (CNS)
Heart
Arms
Eyes
Legs
Teeth
Palate
External genitalia
Ear
Physiological defects and
minor structural abnormalitiesMajor structural abnormalities
Heart Heart
Arm
Leg
Eye Eye Ear Ear Ear
Brain
321Weeks
Period of
the ovum
Period of the embryo Period of the fetus
Most common
site of birth
defect
Most likely
effect
Severity of
defect
Dark shading
indicates
highly
sensitive
period
4 5 6 7 8 12 16 20–36 38
Palate
Brain
Teeth External genitalia
CNS
FIGURE 2.16 Sensitive periods of prenatal development The most sensitive or critical period
of prenatal development is the embryonic period. During the first 2 weeks, before implantation in the
uterus, the zygote is generally not susceptible to environmental factors. every major organ system
of the body undergoes all or a major part of its development between the 3rd and the 9th week. The
dark green portions of the bars in the figure denote the times of most rapid development when major
defects originate. The light green portions indicate periods of continued but less rapid development
when minor defects may occur. (adapted from Moore & persaud, 1993)

P R E n A t A l D E v E l O P M E n t n 59
sexually active people of childbearing age need to be aware of be­
haviors that could compromise the health of a child they might
conceive.
Another crucial factor influencing the severity of teratogenic
effects is the amount and length of exposure. Most teratogens
show a dose–response relation: the greater the fetus’s exposure to
a potential teratogen, the more likely it is that the fetus will suffer
damage and the more severe any damage is likely to be.
Avoiding environmental agents that have teratogenic effects
is complicated by the fact that they often cannot be readily iden­
tified. One reason is that environmental risk factors frequently
occur in combination, making it difficult to separate out their ef­
fects. For families living in urban poverty, for example, it is hard to
tease apart the effects of poor maternal diet, exposure to airborne
pollution, inadequate prenatal care, and psychological stress re­
sulting from underemployment, single parenthood, and living in
crime­ridden neighborhoods.
Furthermore, the presence of multiple risk factors can have a
cumulative impact. For example, in the case of marginal prena­
tal nutrition, the fetus’s metabolism adjusts to the level of nutritional deficiency
experienced in the womb and does not reset itself after birth. In a postnatal envi­
ronment with abundant opportunities for caloric intake, this sets the stage for the
development of overweight and obesity. Such belated emergence of effects of pre­
natal experience is referred to as fetal programming, because experiences during the
prenatal period “program the physiological set points that will govern physiology
in adulthood” (Coe & Lubach, 2008).
The effects of teratogens can also vary according to in-
dividual differences in genetic susceptibility (probably in
both the mother and the fetus). Thus, a substance that is
harmless to most people may trigger problems in a minor­
ity of individuals, whose genes predispose them to be af­
fected by it.
Finally, identifying teratogens is further complicated
by the existence of sleeper effects, in which the impact of
a given agent may not be apparent for many years. For
example, between the 1940s and 1960s, the hormone di­
ethylstilbestrol (DES) was commonly used to prevent mis­
carriage and had no apparent ill effects on babies born to
women who had taken it. However, in adolescence and
adulthood, these offspring turned out to have elevated
rates of cervical and testicular cancers.
An enormous number of potential teratogens have been
identified, but we will focus only on some of the most
common ones, emphasizing in particular those that are re­
lated to the behavior of the pregnant woman. Table 2.2
includes the agents discussed in the text as well as several additional ones, but you
should be aware that there are numerous other agents known to be, or suspected of
being, hazardous to prenatal development.
Legal drugs Although many prescription and over­the­counter drugs are per­
fectly safe for pregnant women, some are not. Pregnant women (and women
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This young artist was damaged while in the
womb because his mother took the drug tha-
lidomide. She must have taken the drug in
the second month of her pregnancy, the time
when the arm buds develop—an unfortunate
example providing clear evidence of the
importance of timing in how environmental
agents can affect the developing fetus.
TABLE 2.2
Some environmental hazards to Fetus or Newborn
Drugs Maternal Disease
Alcohol AIDS
Accutane Chicken pox
Birth control pills (sex hormones) Chlamydia
Cocaine Cytomegalovirus
Heroin Gonorrhea
Marijuana Herpes simplex (genital herpes)
Methadone Influenza
Tobacco Mumps
Environmental Pollutants Rubella (3-day measles)
Lead Syphilis
Mercury Toxoplasmosis
PCBs
Note: This list of dangerous elements is not comprehensive; there are many other agents in the environ-
ment that can have a negative impact on developing fetuses or on newborns during the birth process.
dose–response relation n a rela-
tion in which the effect of exposure to
an element increases with the extent of
exposure (prenatally, the more exposure
a fetus has to a potential teratogen, the
more severe its effect is likely to be)

60 n chapTer 2 PREnAtAl DEvElOPMEnt AnD thE nEwBORn PERIOD
who have reason to think they might soon become pregnant) should take drugs
only under the supervision of a physician. This issue can become particularly
acute in the face of public health emergencies like the 2009 H1N1 (swine flu)
pandemic, during which even some physicians were confused about the appro­
priateness of common medications for pregnant women, including the influenza
vaccine and acetaminophen (Tylenol) (Rasmussen, 2012). Other prescription
drugs that are in common use by women of childbearing age, such the acne med­
ication isotretinoin (Accutane), are known human teratogens that cause severe
birth defects or fetal death. Indeed, because of the unambiguous relationship
between Accutane and birth defects, physicians require women to comply with
multiple contraceptive measures and ongoing pregnancy tests before prescribing
the drug.
The two legal “drugs” that wreak the most havoc on fetal development are ciga­
rettes (nicotine) and alcohol. Because the use of these substances represents a life­
style choice rather than a medical remedy for a specific condition (like flu shots,
antiseizure medications, or Accutane), their effects are particularly widespread.
CIGARETTE SMOKING We all know that smoking is unhealthy for the smoker, and
there is abundant evidence that it is not good for the smoker’s fetus, either. When
a pregnant woman smokes a cigarette, she gets less oxygen, and so does her fetus.
Indeed, the fetus makes fewer breathing movements while its mother is smoking.
In addition, the fetuses of smokers metabolize some of the cancer­causing agents
contained in tobacco. And because the mother­to­be inhales cigarette gases when
someone else is smoking nearby, secondhand smoke has an indirect effect on fetal
oxygen.
The main developmental consequences of maternal smoking are slowed fetal
growth and low birth weight, both of which compromise the health of the new­
born. In addition, evidence suggests that smoking may be linked to increased risk
of sudden infant death syndrome (SIDS) (discussed in Box 2.4) and a variety
of other problems, including lower IQ , hearing deficits, and cancer.
In spite of the well­documented negative effects of maternal smoking
on fetal development, it is estimated that approximately 1 in 10 women in
the United States smokes during pregnancy (Centers for Disease Control,
2009; Child Trends, 2012). For women who manage to quit smoking during
pregnancy, the relapse rate is high after they give birth; roughly half begin
smoking again within the first 6 months after their baby is born. Taken to­
gether, these data show that many infants are exposed to a known terato­
gen before birth, and numerous additional infants are exposed to a known
health hazard after birth. Given that the negative effects of maternal smok­
ing on fetal development are well publicized, you may not find it surprising
that mothers who nevertheless smoke during pregnancy are less sensitive
and less warm in interactions with their young infants (Schuetze, Eiden, &
Dombkowski, 2006).
ALCOHOL Alcohol is currently “the most common human teratogen”
(Ramadoss et al., 2008). Maternal alcohol use is the leading cause of fetal
brain injury and is generally considered to be the most preventable cause.
According to data collected between 2005 and 2010, approximately 7.6% of
women used alcohol during their pregnancies (Centers for Disease Control,
2012). Surprisingly, women who are White, older than 35 years, and em­
ployed are more likely to drink during pregnancy than are women who are
non­White, younger than 24 years, and unemployed. This statistic reverses
This woman is endangering the health
of her fetus.
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P R E n A t A l D E v E l O P M E n t n 61
BOX 2 .4: applications
FACE UP TO WAKE UP
For parents, nothing is more terrifying to
contemplate than the death of their child.
New parents are especially frightened by
the specter of sudden infant death syndrome
(SIDS). SIDS refers to the sudden, unex-
pected, and unexplained death of an infant
younger than 1 year. The most common
SIDS scenario is that an apparently healthy
baby, usually between 2 and 5 months of
age, is put to bed for the night and found
dead in the morning. In the United States,
the incidence of SIDS is 56 per 10,000
live births, making it the leading cause of
infant mortality between 28 days and 1
year of age (Task Force on Sudden Infant
Death Syndrome, 2011). African American
and Native American infants are most likely
to die from SIDS, whereas Hispanic Ameri-
can and Asian American infants are least
likely to die from SIDS. These patterns sug-
gest cultural differences in parenting that
might protect some infants from SIDS.
The causes of SIDS are still not well un-
derstood. One hypothesis is that SIDS may
involve an inadequate reflexive response
to respiratory occlusion—that is, an in-
ability to remove or move away from some-
thing covering the nose and mouth (Lipsitt,
2003). Infants may be particularly vulner-
able to SIDS between 2 and 5 months of
age because that is when they are making
a transition from neonatal reflexes under
the control of lower parts of the brain (the
brainstem) to deliberate, learned behaviors
mediated by higher brain areas (cerebral
cortex). A waning respiratory occlusion re-
flex during this transition period may make
infants less able to effectively pull their
head away from a smothering pillow or to
push a blanket away from their face.
In spite of the lack of certainty about the
causes of SIDS, researchers have identi-
fied several steps that parents can take to
decrease the risk to their baby. The most
important one is putting infants to sleep
on their back, reducing the possibility
of anything obstructing their breathing.
Sleeping on the stomach increases the risk
of SIDS more than any other single factor
(e.g., Willinger, 1995). (With respect to
the cultural differences in the incidence of
SIDS mentioned above, it is significant that
Hispanic American parents are the most
likely to put their infants to sleep on their
back [73%], and African Americans the
least likely to do so [53%].) A campaign
encouraging parents to put their infants to
sleep on their back—the “back to sleep”
movement—has contributed to a dramatic
reduction in the number of SIDS victims.
Second, to lower the risk of SIDS, par-
ents should not smoke. If they do smoke,
they should not smoke around the baby.
Infants whose mothers smoke during preg-
nancy and/or after the baby’s birth are more
than 3½ times more likely to succumb
to SIDS than are babies who are not ex-
posed to smokers in their home (Anderson,
Johnson, & Batal, 2005).
Third, babies should sleep on a firm mat-
tress with no pillow or crib bumpers. Soft
bedding can trap air around the infant’s
face, causing the baby to breathe in his or
her own carbon dioxide instead of oxygen.
Fourth, infants should not be wrapped
in lots of blankets or clothes. Being overly
warm is associated with SIDS.
Fifth, infants who are breastfed are less
likely to succumb to SIDS (e.g., Hauck
et al., 2011). Why would breastfeeding
protect infants from SIDS? One possible
reason is that breastfed infants are more
easily aroused from sleep than formula-fed
infants, and thus may more easily detect
when their airflow is interrupted (Horne et
al., 2004).
One unanticipated consequence of the
“back to sleep” movement has been that
North American infants are now beginning
to crawl slightly later than those in previ-
ous generations, presumably because of
reduced opportunity to strengthen their
muscles by pushing up off their mattress.
Parents are encouraged to give their babies
supervised “tummy time” to exercise their
muscles during the day.
“Face Up to Wake Up.” The parents of this infant are following the good advice of the
foundation dedicated to lowering the incidence of SIDS worldwide. Since the inaugu-
ration of this campaign, SIDS in the United States has declined to half its previous
rate (Task Force on Sudden Infant Death Syndrome, 2011).
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sudden infant death syndrome
(SIDS) n the sudden, unexpected death
of an infant less than 1 year of age that
has no identifiable cause

62 n chapTer 2 PREnAtAl DEvElOPMEnt AnD thE nEwBORn PERIOD
the more typical pattern of maternal teratogen exposure, which tends to predomi­
nate among expectant mothers with fewer economic and social resources.
Women who use alcohol before becoming pregnant (about half of women of
childbearing age) are most likely to continue using alcohol during pregnancy. In
part, this is due to the fact that in the United States, 40% of women do not real­
ize that they are pregnant until after the fourth week of gestation, when they have
missed a menstruation cycle. As we have seen, those early weeks are a crucial period
in fetal development.
When a pregnant woman drinks, the alcohol in her blood crosses the placenta
into both the fetus’s bloodstream and the amniotic fluid. Thus, the fetus gets alco­
hol directly in its bloodstream, and indirectly by drinking an amniotic­fluid cock­
tail. Concentrations of alcohol in the blood of mother and fetus quickly equalize,
but the fetus has less ability to metabolize and remove alcohol from its blood,
so it remains in the fetus’s system longer. Immediate behavioral effects on the
fetus include altered activity levels and abnormal startle reflexes (Little, Hepper, &
Dornan, 2002).
In the long run, maternal drinking can result in fetal alcohol spectrum disorder
(FASD) (Sokol et al., 2003), which comprises a continuum of alcohol­related
birth defects. Babies born to alcoholic women often exhibit a condition known
as fetal alcohol syndrome (FAS) ( Jacobson & Jacobson, 2002; Jones & Smith, 1973;
Streissguth, 2001; Streissguth et al., 1993). The most obvious symptoms of FAS
are facial deformities like those shown in Figure 2.17. Other forms of FAS can in­
clude varying degrees of intellectual disability, attention problems, and hyperactiv­
ity. Many children who were prenatally exposed to alcohol and show similar but
fewer symptoms are diagnosed with fetal alcohol effects (FAE) (Mattson et al., 1998).
Even moderate drinking during pregnancy (i.e., less than one drink per day) can
have both short­ and long­term negative effects on development. So can occasional
drinking if it involves binge drinking (more than five drinks per episode) (e.g.,
Hunt et al., 1995; Sokol et al., 2003). And according to an analysis of self­report
FIGURE 2.17 Facial Features of FaS These two children display the three primary diagnostic
facial features of fetal alcohol syndrome: small eyes (as measured across); the absence of, or flattening
of, the vertical groove between the nose and the upper lip (smooth philtrum); and a thin upper lip. It
appears that the more pronounced these features are in an affected child, the greater the likelihood
that the child experienced prenatal brain damage. roughly 1 in 1000 infants born in the United States
has FaS.
fetal alcohol spectrum disorder
(FASD) n the harmful effects of maternal
alcohol consumption on a developing
fetus. Fetal alcohol syndrome (FAS)
involves a range of effects, including
facial deformities, mental retardation,
attention problems, hyperactivity, and
other defects. Fetal alcohol effects (FAE)
is a term used for individuals who show
some, but not all, of the standard effects
of FAS.
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P R E n A t A l D E v E l O P M E n t n 63
data from 2006 through 2010, 1.4% of pregnant women in the United States
engage in at least one incident of binge drinking during their pregnancy (Centers
for Disease Control, 2012).
Given the potential outcomes and the fact that no one knows whether there is
a safe level of alcohol consumption for a pregnant woman, the best approach for
expectant mothers is to avoid alcohol altogether.
Illegal drugs In the United States, the use of illegal drugs during pregnancy
ranges from a low of 3.1% among Hispanic women to a high of 7.7% among non­
Hispanic Black women (National Survey on Drug Use and Health, 2012). Almost
all commonly abused illegal drugs have been shown to be, or are suspected of being,
dangerous for prenatal development. It has proved difficult to pin down exactly
how dangerous particular drugs are, however, because pregnant women who use
one illegal substance often use others, along with smoking cigarettes and drinking
alcohol (Frank et al., 2001; Lester, 1998; Smith et al., 2006).
Prenatal exposure to marijuana, the illegal substance most commonly used
by women of reproductive age in the United States, is suspected of affecting
memory, learning, and visual skills after birth (Fried & Smith, 2001; Mereu
et al., 2003). Cocaine in its various forms is the second most common illegal
drug abused by young American women (Substance Abuse and Mental Health
Services Administration, 2011). Although some early reports of devastating ef­
fects from cocaine use during pregnancy turned out to be exaggerated, such use
has been associated with fetal growth retardation and premature birth (Hawley
& Disney, 1992; Singer et al., 2002). In addition, infants who endured prena­
tal exposure to cocaine have impaired ability to regulate arousal and attention
(e.g., DiPietro et al., 1995; Lewkowicz, Karmel, & Gardner, 1998). Especially
distressing is the case of newborns born to coke­ addicted mothers, because they
have to go through withdrawal just like a reforming addict (Kuschel, 2007).
Longitudinal studies of the development of cocaine­exposed children have re­
vealed persistent, although sometimes subtle, cognitive and social deficits (Lester,
1998). These deficits can be ameliorated to some degree, as suggested by improved
outcomes among affected children who were adopted into supportive middle­class
families (Koren et al., 1998).
environmental pollutants The bodies and bloodstreams of most Americans (in­
cluding women of childbearing age) contain a noxious mix of toxic metals, syn­
thetic hormones, and various ingredients of plastics, pesticides, and herbicides that
can be teratogenic (Moore, 2003). Echoing the story of Minamata disease, evi­
dence has accumulated that mothers whose diet was high in Lake Michigan fish
with high levels of polychlorinated biphenyls (PCBs) had newborns with small
heads. The children with the highest prenatal exposure to PCBs had slightly lower
IQ scores as long as 11 years later ( Jacobson & Jacobson, 1996; Jacobson et al.,
1992). In China, the rapid modernization that has led to economic success has also
taken a toll on health in general, and has led to a dramatic increase in pollution­
related birth defects due to the unregulated burning of coal, water pollution, and
pesticide use (e.g., Ren et al., 2011).
Occupational hazards Many women have jobs that bring them into contact with
a variety of environmental elements that are potentially hazardous to prenatal de­
velopment. Tollbooth collectors, for example, are exposed to high levels of auto­
mobile exhaust; farmers, to pesticides; and factory workers, to numerous chemicals.

64 n chapTer 2 PREnAtAl DEvElOPMEnt AnD thE nEwBORn PERIOD
As Figure 2.18 shows, even noise pollution can negatively affect fetal de­
velopment. Employers and employees alike are grappling with how best to
protect pregnant women from potential teratogens without subjecting them
to job discrimination.
Maternal Factors
Because the mother­to­be provides the most immediate environment for
her fetus, some of her characteristics can affect prenatal development. These
characteristics include age, nutritional status, health, and stress level.
age A pregnant woman’s age is related to the outcome of her pregnancy.
Infants born to girls 15 years or younger are three to four times more likely
to die before their first birthday than are those born to mothers who are
between 23 and 29 (Phipps, Blume, & DeMonner, 2002). However, the
rate of teenage pregnancy has declined substantially in recent years, and
in 2010, the birth rate for teenagers fell to the lowest recorded level in the
United States (34 births per 1000 females younger than 20; Hamilton,
Martin, & Ventura, 2011).
A different age­related cause for concern has to do with the increasing
age of first­time mothers. In recent decades, many women have chosen to wait
until their 30s or 40s to have children. At the same time, techniques to treat infer­
tility have continued to improve, increasing the likelihood of conception for older
parents. Older mothers are at greater risk for many negative outcomes for them­
selves and their fetus, including fetal chromosomal abnormalities (see Chapter 3)
and birth complications.
Nutrition The fetus depends on its mother for all its nutritional requirements. If
a pregnant woman has an inadequate diet, her unborn child may also be nutrition­
ally deprived (Pollitt et al., 1996). An inadequate supply of specific nutrients or
65–75 dB
Noise exposure during pregnancy
75–85 dB 85–95 dB
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FIGURE 2.18 hearing loss in children
whose mothers worked in a noisy factory
while pregnant The greater the noise expo-
sure a pregnant woman experienced, the
greater the hearing impairment of her child.
SOURCE: lAlAnDE, hÉtU, & lAMBERt, 1986
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These poor parents in Bolivia are wor-
rying about how they are going to feed
their children—a situation all too common
throughout the world.

P R E n A t A l D E v E l O P M E n t n 65
vitamins can have dramatic consequences. For example, women who get too little
folic acid (a form of B vitamin) are at high risk for having an infant with a neural­
tube defect such as spina bifida (see Figure 2.5). General malnutrition affects the
growth of the fetal brain: newborns who received inadequate nutrients while in
the womb tend to have smaller brains containing fewer brain cells than do well­
nourished newborns.
Because malnutrition is more common in impoverished families, it often coin­
cides with the host of other risk factors associated with poverty, making it difficult
to isolate its effects on prenatal development (Lozoff, 1989; Sigman, 1995). How­
ever, one unique study of development in very extreme circumstances made it possi­
ble to assess certain effects of malnutrition independent of socioeconomic status (Stein
et al., 1975). In parts of Holland during World War II, people of all income and
education levels suffered severe famine. Later, the health records of those Dutch
women who had been pregnant during this time of general malnourishment were
examined. Their babies were, on average, underweight at birth, but the severity of
effects depended on how early in their pregnancy the women had become malnour­
ished. Those who became malnourished only in the last few months of pregnancy
tended to have slightly underweight babies with relatively small heads. However,
those whose malnutrition started early in their pregnancy often had very small
babies with serious physical defects.
Disease Although most maternal illnesses that occur during a pregnancy have no
impact on the fetus, some do. For example, if contracted early in pregnancy, rubella
(also called the 3­day measles) can have devastating developmental effects, in­
cluding major malformations, deafness, blindness, and intellectual disabilities. Any
woman of childbearing age who does not have immunities against rubella should
be vaccinated before becoming pregnant.
Sexually transmitted diseases (STDs) that have become increasingly common
throughout the world are also quite hazardous to the fetus. Cytomegalovirus, a
type of herpes virus that is present in 50% to 80% of the adult population in the
United States, is currently the most common cause of congenital infection (1 of
every 150 infants). It can damage the fetus’s central nervous system and cause a
variety of other serious defects. Genital herpes can also be very dangerous: if the
infant comes into contact with active herpes lesions in the birth canal, blindness or
even death can result. HIV infection is sometimes passed to the fetus in the womb
or during birth, but the majority of infants born to women who are HIV­positive
or have AIDS do not become infected themselves. HIV can also be transmitted
through breast milk after birth, but recent research suggests that breast milk con­
tains a carbohydrate that may actually protect infants from HIV infection (Bode
et al., 2012).
Evidence has been accumulating for effects of maternal illness on the develop­
ment of psychopathology later in life. For example, the incidence of schizophrenia is
higher for individuals whose mothers had influenza (flu) during the first trimester
of pregnancy (Brown et al., 2004). Maternal flu may interact with genetic or other
factors to lead to mental illness.
Maternal emotional state For centuries, people have believed that a woman’s
emotions can affect her fetus. This view is now supported by research suggesting
that maternal stress can have negative consequences for development (DiPietro,
2012). For example, the fetuses of women who reported higher levels of stress

66 n chapTer 2 PREnAtAl DEvElOPMEnt AnD thE nEwBORn PERIOD
during pregnancy were more physically active throughout their
gestation than were the fetuses of women who felt less stressed
(DiPietro, Hilton et al., 2002). This increased activity is likely
related to hormones, including adrenaline and cortisol, that the
mother secretes in response to stress (Relier, 2001). Such effects
can continue after birth. In a study that involved more than 7000
pregnant women and their infants, maternal anxiety and depres­
sion during pregnancy were assessed. The higher the level of dis­
tress the pregnant women reported, the higher the incidence of
behavior problems in their children at 4 years of age—including
hyperactivity and inattention in boys, conduct problems in girls,
and emotional problems in both boys and girls (O’Connor et al.,
2002). Findings such as these, linking prenatal maternal stress
to postnatal behavior problems, are likely to also be mediated by
increased levels of maternal hormones, such as cortisol, that are
elicited by stress (Susman et al., 2001; Susman, 2006).
Like other types of teratogens, it is difficult to tease apart the
specific effects of maternal stress from other factors that often
co­occur with stress; for example, expectant mothers who are
stressed during pregnancy are likely to still be stressed after giv­
ing birth. That said, the increased popularity of prenatal yoga
and meditation classes may point to ways in which pregnancy­
related stress may be reduced, with potential benefits for both
mother and fetus.
review:
The most rapid period of development starts at conception, with the union of egg and sperm,
and continues for roughly 9 months, divided into three developmental periods: germinal, em-
bryonic, and fetal. The processes through which prenatal development occurs include cell
division, cell migration, cell differentiation, and cell death. Every major organ system un-
dergoes all or a substantial part of its development between the 3rd and 8th week following
conception, making this a sensitive period for potential damage from environmental hazards.
Scientists have learned an enormous amount about the behavior and experience of the
developing organism, which begins to move at 5 to 6 weeks after conception. Some behav-
iors of the fetus contribute to its development, including swallowing amniotic fluid and mak-
ing breathing motions. The fetus has relatively rich sensory experience from stimulation both
within and outside the womb, and this experience is the basis for fetal learning. Some effects
of fetal learning after birth have been shown to be persistent.
Many environmental agents can have a negative impact on prenatal development. The
most common teratogens in the United States are cigarette smoking, alcohol consumption,
and environmental pollution. Maternal factors (malnutrition, illness, stress, and so forth) can
also cause problems for the developing fetus and child. Timing is crucial for exposure to many
teratogens; the severity of effects is also related to the amount and length of exposure, as well
as to the number of different negative factors with which a fetus has to contend.
The Birth Experience
Approximately 38 weeks after conception, contractions of the muscles of the uterus
begin, initiating the birth of the baby. Typically, the baby has already contributed
to the process by rotating itself into the normal head­down position. In addition,
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prenatal exercise classes, as well as yoga
or meditation classes, may help reduce
pregnancy-related stress.

t h E B I R t h E X P E R I E n C E n 67
the maturing lungs of the fetus may release a protein that triggers the onset of
labor. Uterine contractions, as well as the baby’s progress through the birth canal,
are painful for the mother, so women in labor are often given pain­relieving drugs.
Women who self­report a great deal of fear about childbirth earlier in their preg­
nancies are more likely to choose pain medications, such as epidurals, during the
birth process (Haines et al., 2012). Although these drugs can help the mother get
through childbirth more comfortably, they do not help her baby. Indeed, many ob­
stetric medications slow labor, and prolonged labor increases the chance of fetal
oxygen deprivation, which can result in brain damage.
Is birth as painful for the newborn as for the mother? Actually, there is good rea­
son to believe that birth is not particularly painful for the baby. Compare how much
pain you feel when you pinch and pull on a piece of skin on your forearm versus
when you wrap your hand around your forearm and squeeze as tightly as you can.
The stretching is painful, but the squeezing is not. The mother’s pain comes from
her tissues being greatly stretched, but the baby experiences squeezing. Hence, the
experiences of the two participants are not really comparable (Maurer & Maurer,
1988). Childbirth programs designed to prevent birth from being painful and trau­
matic for newborns are probably based on faulty premises.
Furthermore, the squeezing that the fetus experiences during birth serves sev­
eral important functions. First, it temporarily reduces the overall size of the fetus’s
disproportionately large head, allowing it to pass safely through the mother’s pel­
vic bones. This is possible because the skull is composed of separate plates that can
overlap one another slightly during birth (see Figure 2.19). The squeezing of the
fetus’s head during birth also stimulates the production of hormones that help the
fetus withstand mild oxygen deprivation during birth and to regulate breathing
after birth. The squeezing of the fetus’s body also forces amniotic fluid out of
the lungs, in preparation for the newborn’s first, crucial gasp of air (Lagercrantz
& Slotkin, 1986; Nathanielsz, 1994). This first breath usually comes by way of
the birth cry, which is a very efficient mechanism for jump­starting respiration: a
strong cry not only obtains some essential oxygen but also forces open the small air
sacs in the lungs, making subsequent breaths easier. (An important disadvantage of
cesarean deliveries is that surgical removal from the womb deprives the fetus of the
squeezing action of a normal delivery, increasing the likelihood of its experiencing
respiratory problems as a newborn.)
FIGURE 2.19 head plates pres-
sure on the head during birth can
cause the separate plates of the
skull to overlap, resulting in a tem-
porarily misshapen head. Fortu-
nately, the condition rapidly corrects
itself after birth. The “soft spot,” or
fontanel, is simply the temporary
space between separate skull plates
in the top of the baby’s head.

68 n chapTer 2 PREnAtAl DEvElOPMEnt AnD thE nEwBORn PERIOD
Diversity of Childbirth Practices
Although the biological aspects of birth are pretty much the same everywhere,
childbirth practices vary enormously. As with many human behaviors, what is con­
sidered a normal and desirable birth custom in one society may seem strange or
deviant—or even dangerous—in another.
All cultures pursue the dual goals of safeguarding the survival and health of both
the mother and the baby and ensuring the social integration of the new person.
Groups differ, however, regarding the relative importance they give to these goals.
An expectant mother on the South Pacific island of Bali assumes that her husband
and other kin, along with any children she may already have, will all want to be
present at the joyous occasion of the birth of a new child. Her female relatives, as
well as a midwife, actively help her throughout the birth, which occurs in her home.
Having already been present at many births, the Balinese woman knows what to
expect from childbirth, even when it is her first child (Diener, 2000).
A very different scenario has been the tradition in the United States, where the
woman in labor usually withdraws almost totally from her everyday life. In most
cases, she enters a hospital to give birth, typically attended by a small group of fam­
ily or close friends. The birth is supervised by a variety of medical personnel, most
of whom are strangers. Unlike her Balinese counterpart, the first­time U.S. mother
has probably never witnessed a birth, so she may not have very realistic expectations
about the birth process. Also, unlike her counterparts in most societies, a U.S.
woman in labor has a 33% chance of having a surgical delivery by cesarean—a rate
that has steadily increased in the United States over the past 2 decades (Martin et
al., 2012). There are a number of reasons for the ever higher rate of surgical deliver­
ies, including a vastly increased rate of multiple births (discussed below), schedul­
ing convenience for the physician and/or the parents, and physicians’ attempts to
decrease risk of lawsuits concerning medical malpractice should problems arise
from a vaginal birth (e.g., Yang et al., 2009).
Underlying the Balinese approach to childbirth is great emphasis on the social
goal of immediately integrating the newborn into the family and community—
hence the presence of many kin and friends to support mother and baby. In con­
trast, modern Western groups have elevated the physical health of the mother and
newborn above all other concerns. The belief that childbirth is safer in a hospital
setting outweighs the resulting social isolation of mother and baby.
The practices of both societies have changed to some degree. In the United
States, the social dimensions of birth are increasingly recognized by doctors and
hospitals, which often now employ certified nurse­midwives as alternative practi­
tioners for expectant parents who prefer a less medicalized birth plan. As in Bali,
various family members—sometimes even including the parents’ other children—
are encouraged to be present to support the laboring mother and to share a family
experience. Another increasingly common practice in the United States is the use
of doulas, individuals trained to assist women in terms of both emotional and physi­
cal comfort during labor and delivery. This shift has been accompanied by more
moderate use of delivery drugs, thereby enhancing the woman’s participation in
childbirth and her ability to interact with her newborn. In addition, many expect­
ant parents attend childbirth education classes, where they learn some of what their
Balinese counterparts pick up through routine attendance at births. Social support
is a key component of these programs; the pregnant woman’s husband or partner, or
some other supportive person, is trained to assist her during the birth. Such child­
birth programs are generally beneficial (Lindell, 1988), and obstetricians routinely

t h E B I R t h E X P E R I E n C E n 69
advise expectant couples to enroll in them. At the same time that these changes are
occurring in the United States, Western medical practices are increasingly adopted
in traditional, nonindustrialized societies like Bali, in an effort to improve newborn
survival rates.
review:
Research on the birth process has revealed that many aspects of the experience of being
born, including squeezing in the birth canal, have adaptive value and increase the likelihood
of survival for the newborn. Although cultural groups differ in their beliefs and practices re-
lated to childbirth, these differences are decreasing as expectant mothers gain access to
more diverse birthing options.
This childbirth in Brazil is quite different
from the norm in the United States. The
baby was born at home, welcomed by his
father, older brother, and grandmother. also
present are an obstetrician and midwife who
assisted with the birth.
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the United States.

70 n chapTer 2 PREnAtAl DEvElOPMEnt AnD thE nEwBORn PERIOD
The Newborn Infant
A healthy newborn is ready and able to continue the developmental saga in a new
environment. The baby begins interacting with that environment right away, ex­
ploring and learning about newfound physical and social entities. Newborns’ explo­
ration of this uncharted territory is very much influenced by their state of arousal.
State of Arousal
State refers to a continuum of arousal, ranging from deep sleep to intense activ­
ity. As you well know, your state dramatically affects your interaction with the
environment—with what you notice, do, learn, and think about. It also affects
the ability of others to interact with you. State strongly mediates how young in­
fants experience the world around them.
Figure 2.20 depicts the average amount of time in a 24­hour period that
Western newborns typically spend in each of six states, ranging from quiet
sleep to crying. Within this general pattern, however, there is a great deal of
individual variation. Some infants cry relatively rarely, whereas others cry for
hours every day; some babies sleep much more, and others much less, than the
16­hour average shown in the figure. Some infants spend more than the aver­
age of 2½ hours in the awake­alert state, in which they are fairly inactive but
attentive to the environment. To appreciate how these differences might affect
parent–infant interactions, imagine yourself as the parent of a newborn who
cries more than the average, sleeps little, and spends less time in the awake­
alert state. Now imagine yourself with a baby who cries relatively little, sleeps
well, and spends an above­average amount of time quietly attending to you
and the rest of his or her environment (see Figure 2.21). Clearly, you would have
many more opportunities for pleasurable interactions with the second newborn.
The two newborn states that are of particular concern to parents—sleeping and
crying—have both been studied extensively.
Sleep
Figure 2.22 summarizes several important facts about sleep and its development,
two of which are of particular importance. First, “sleeping like a baby” means, in
part, sleeping a lot; on average, newborns sleep twice as much as young adults do.
Total sleep time declines regularly during childhood and continues to decrease,
although more slowly, throughout life.
Second, the pattern of two different sleep states—REM sleep and
non-REM sleep—changes dramatically with age. Rapid eye move-
ment (REM) sleep is an active sleep state that is associated with
dreaming in adults and is characterized by quick, jerky eye move­
ments under closed lids; a distinctive pattern of brain activity; body
movements; and irregular heart rate and breathing. Non-REM
sleep, in contrast, is a quiet sleep state characterized by the absence
of motor activity or eye movements and more regular, slow brain
waves, breathing, and heart rate. As you can see in Figure 2.22,
REM sleep constitutes fully 50% of a newborn’s total sleep time.
The proportion of REM sleep declines quite rapidly to only 20% by
3 or 4 years of age and remains low for the rest of life.
Why do infants spend so much time in REM sleep? Some re­
searchers believe that it helps develop the infant’s visual system.
1 hr.
2.5 hrs.
2.5 hrs.
2 hrs.
8 hrs.
8 hrs.
Quiet sleep
Active sleep
Drowsing
CryingActive
awake
Alert
awake
FIGURE 2.20 Newborn states This
figure shows the average proportion of time,
in a 24-hour day, that Western newborns
spend in each of the six states of arousal.
There are substantial individual and cultural
differences in how much time babies spend
in the different states.
FIGURE 2.21 Quiet-alert state The par-
ents of this quiet-alert newborn have a good
chance of having a pleasurable interaction
with the baby.
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state n level of arousal and engagement
in the environment, ranging from deep
sleep to intense activity
rapid eye movement (REM) sleep n
an active sleep state characterized by
quick, jerky eye movements under closed
lids and associated with dreaming in
adults
non-REM sleep n a quiet or deep
sleep state characterized by the absence
of motor activity or eye movements and
more regular, slow brain waves, breathing,
and heart rate

t h E n E w B O R n I n F A n t n 71
The normal development of the human visual system, including the visual area of
the brain, depends on visual stimulation, but relatively little visual stimulation is ex­
perienced in the womb (particularly in contrast to fetal auditory stimulation, which,
as you will see in the next section, is extensive). In addition, the fact that newborns
spend so much time asleep means that they do not have much opportunity to amass
waking visual experience. The high level of internally generated brain activity that
occurs during REM sleep may help to make up for the natural deprivation of visual
stimulation, facilitating the early development of the visual system in both fetus
and newborn (Roffwarg, Muzio, & Dement, 1966). This theory is supported by a
study showing that newborns who had been given a high level of extra visual stimu­
lation during the day spent less of their subsequent sleep time in REM sleep than
did infants exposed to lower levels of visual stimulation (Boismier, 1977).
Another distinctive feature of sleep in the newborn period is that napping new­
borns may actually be learning while asleep. In one study that investigated this
possibility, infants were exposed to recordings of Finnish vowel sounds while they
slumbered in the newborn nursery. When tested in the morning, their brain activity
revealed that they recognized the sounds they had heard while asleep (Cheour et
al., 2002). In a recent study, researchers trained sleeping neonates to make an eye­
movement response to a puff of air toward their closed eyelids (Fifer et al., 2010).
During the training phase, the newborns were repeatedly presented with a tone just
before each puff of air. Given this experience, they quickly learned to expect the air
puff after the tone, as evidenced by their making an eye movement in response to
the tone alone. Newborns seem able to learn in their sleep because their slumbering
brains do not become disconnected from external stimulation to the same extent
that the brains of older individuals do.
FIGURE 2.22 Total sleep and propor-
tion of reM and non-reM sleep across
the life span Newborns average a total of
16 hours of sleep, roughly half of it in reM
sleep. The total amount of sleep declines
sharply throughout early childhood and
continues to decline much more slowly
throughout life. From adolescence on, reM
sleep constitutes only about 20% of total
sleep time. (adapted from roffwarg et al.,
1966, and from a later revision by these
authors)
1–15
days
3 – 5
months
6 – 23
months
2–
3
3 –
5
5 –
9
10 –
13
14 –
18
19 – 30 33 – 45 50 – 70 70 – 85
14 13 12 11 10.5 10 8.5 7.75 7 6 5.75
To
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InfantsNeonate Children
Age (in years unless labeled otherwise)
Adolescents Adults Old Age
NREM sleep
Waking
Hours
REM sleep
16
24
2
4
6
8
10
12
14
16
0

72 n chapTer 2 PREnAtAl DEvElOPMEnt AnD thE nEwBORn PERIOD
Another difference between the sleep of young infants and older individuals (not
reflected in Figure 2.22) is in sleep–wake cycles. Newborns generally cycle between
sleep and waking states several times in a 24­hour period, sleeping slightly more at
night than during the day (Whitney & Thoman, 1994). Although newborns are
likely to be awake during part of their parents’ normal sleep time, they gradually
develop the more mature pattern of sleeping through the night.
The age at which infants’ sleep patterns come to match those of adults depends
very much on cultural practices and pressures. For example, many infants in the
United States sleep through the night by around 4 months of age—a development
actively encouraged by their parents. Indeed, tired parents employ many different
strategies to get their infants to sleep through the night—from adopting elaborate,
often extended bedtime rituals intended to lull the baby into dreamland to gritting
their teeth and letting the baby cry himself or herself to sleep. (Note: one little­
known but particularly useful strategy for encouraging longer periods of nighttime
sleeping is exposing the infant to bright sunlight during the day [Harrison, 2004].)
In contrast with U.S. parents, Kipsigis parents in rural Kenya are relatively un­
concerned about their infants’ sleep patterns. Kipsigis babies are almost always
with their mothers. During the day, infants are often carried on their mother’s back
as she goes about her daily activities, and at night they sleep with her and are al­
lowed to nurse whenever they awaken. As a consequence, these babies distribute
their sleeping throughout the night and day for several months (Harkness & Super,
1995; Super & Harkness, 1986). Thus, cultures vary not only in terms of where ba­
bies sleep, as you learned in Chapter 1, but also in terms of how strongly parents
attempt to influence when their babies sleep.
Crying
How do you feel when you hear a baby cry? We imagine that, like most people,
you find the sound of a crying infant extremely unpleasant. Why is an infant’s cry
so aversive?
From an evolutionary point of view, adults’ aversion to infants’ crying could have
adaptive value. Infants cry for many reasons—including illness, pain, and hunger—
that require the attention of caregivers. Parents are likely to attempt to quiet their
crying infant by taking care of the infant’s needs, thereby promoting the infant’s
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Most american parents want to avoid the
2 a.m. fate of this young father. They regard
their baby’s sleeping through the night as
a developmental triumph—the sooner, the
better.

t h E n E w B O R n I n F A n t n 73
survival. This fact has led some researchers to suggest that in times of hardship,
such as famine, cranky babies are more likely to survive than are placid ones, pos­
sibly because their distress elicits adult attention and they consequently get more
than their share of scarce food resources (DeVries, 1984).
Parents, especially first­timers, are often puzzled and anxious about why their
baby is crying. Indeed, one of the most frequent complaints pediatricians hear from
parents concerns crying that the parents think is excessive but is actually common
(Barr, 1998; Harkness et al., 1996). With experience, parents become better at in­
terpreting their infants’ crying, identifying characteristics of the cry itself (a sharp,
piercing cry usually signals pain, for example) and considering the context (such as
when the infant’s last feeding was) (Green, Jones, & Gustafson, 1987).
Do all newborns’ cries sound alike? Parents certainly do not think so. In fact,
within the first week after birth, mothers are able to distinguish their own new­
born’s cries from those of other infants (e.g., Cismaresco & Montagner, 1990).
Newborns’ cries are also differentially shaped by the sounds of the language in their
environment. A recent study that compared the crying patterns of French and Ger­
man newborns found that the infants’ cries followed different acoustic patterns that
mimicked the pitch patterns in their home language (Mampe et al., 2009).
After the newborn period, crying behavior typically increases, cresting at about
6 weeks of age, and then declines to about an hour a day for the rest of the first year
(St James­Roberts & Halil, 1991). On a daily basis, the peak time for crying is late
afternoon or evening, which can be quite disappointing to parents looking forward
to interacting with their baby at the end of the workday. Increased crying late in the
day may be due to an accumulation of excess stimulation during the daytime hours.
The nature of crying and the reasons for it change with development. Early on,
crying reflects discomfort from pain, hunger, cold, or overstimu lation, although,
from the beginning, infants also cry from frustration (Lewis, Alessandri, & Sullivan,
1990; Stenberg, Campos, & Emde, 1983). Over time, crying becomes more com­
municative, often seeming geared to “tell” caregivers something and to get them to
respond (Gustafson & Green, 1988).
Soothing What are the best ways to console a crying baby? Most of the
traditional standbys—rocking, singing lullabies, holding the baby up to the
shoulder, giving the baby a pacifier—work reasonably well (R. Campos,
1989; Korner & Thoman, 1970). Many effective soothing techniques involve
moderately intense and continuous or repetitive stimulation. The combina­
tion of holding, rocking, and talking or singing relieves an infant’s distress
better than any one of them alone ( Jahromi, Putnam, & Stifter, 2004).
One very common soothing technique is swaddling, which involves
wrapping a young baby tightly in cloths or a blanket, thereby restricting
limb movement. The tight wrapping provides a constant high level of tactile
stimulation and warmth. This technique is practiced in cultures as diverse
and widespread as those of the Navajo and Hopi in the American Southwest
(Chisholm, 1983), the Quechua in Peru (Tronick, Thomas, & Daltabuit,
1994), and rural villagers in Turkey (Delaney, 2000). Another traditional
approach, distracting an upset infant with interesting objects or events, can
also have a soothing effect, but the distress often resumes as soon as the in­
teresting stimulus is removed (Harman, Rothbart, & Posner, 1997).
Touch can also have a soothing effect on infants. In interactions with
an adult, infants fuss and cry less, and they smile and vocalize more, if the
adult pats, rubs, or strokes them (Field et al., 1996; Peláez­Nogueras et al.,
1996; Stack & Arnold, 1998; Stack & Muir, 1992). Carrying young infants,
carrying infants close to the parent’s body
results in less crying. Many Western parents
are now emulating the traditional carrying
methods of other societies around the world.
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swaddling n a soothing technique, used
in many cultures, that involves wrapping
a baby tightly in cloths or a blanket

74 n chapTer 2 PREnAtAl DEvElOPMEnt AnD thE nEwBORn PERIOD
as is routinely done in many societies around the world, reduces the amount of cry­
ing that they do (Hunziker & Barr, 1986). In fact, a recent study found that cry­
ing infants showed sharper decreases in heart rate, physical movement, and crying
when carried about by their mother than when held in her lap. Similar quieting re­
sponses are seen in maternal carrying in other species (think of how still lion cubs
become when carried by their mother) and are conjectured to be innate coopera­
tive mechanisms that facilitate the mother’s carrying efforts (Esposito et al., 2013).
In other laboratory studies, placing a small drop of something sweet on a dis­
tressed newborn’s tongue has been shown to have a dramatic calming effect (Barr
et al., 1994; Blass & Camp, 2003; Smith & Blass, 1996). A taste of sucrose has an
equally dramatic effect on pain sensitivity; newborn boys who are given a sweet­
ened pacifier to suck during circumcision cry much less than babies who do not
receive this simple intervention (Blass & Hoffmeyer, 1991).
response to distress One question that often concerns parents is how to respond
to their infant’s signals of distress. They wonder whether quick and consistent sup­
portive responses will reward the infant for fussing and crying, and hence increase
these behaviors, or will instead give the infant a sense of security that leads to less
fussing and crying. An answer to this question comes from a longitudinal study
that found that infants whose cries were ignored during the first 9 weeks actually
cried less during the next 9 weeks (Hubbard & van IJzendoorn, 1991). Assessing
the severity of the infant’s distress before responding may be the key factor. If a par­
ent responds quickly to severe distress but delays responding to minor upset, the
infant may learn to cope with less serious problems on his or her own and hence
end up crying less overall.
colic No matter how or how much their parents try to soothe them, some infants
are prone to excessive, inconsolable crying for no apparent reason during the first
few months of life, a condition referred to as colic. Not only do “colicky” babies cry
a lot, but they also tend to have high­pitched, particularly unpleasant cries (Stifter,
Bono, & Spinrad, 2003). The causes of colic are unknown, and may include aller­
gic responses to their mothers’ diets (ingested via breast milk), formula intolerance,
immature gut development, and/or excessive gassiness. Unfortunately, colic is not
a rare condition: more than 1 in 10 young U.S. infants—and their parents—suffer
from it. Fortunately, it typically ends by around 3 months of age and leaves no ill
effects (Stifter & Braungart, 1992; St James­Roberts, Conroy, & Wilsher, 1998).
One of the best things parents with a colicky infant can do is seek social support,
which can provide relief from the stress, frustration, and sense of inadequacy and
incompetence they may feel because they are unable to relieve their baby’s distress.
Negative Outcomes at Birth
Although most recognized pregnancies in an industrialized society result in the
full­term birth of a healthy baby, sometimes the outcome is less positive. The worst
result, obviously, is the death of an infant. A much more common negative outcome
is low birth weight, which can have long­term consequences.
Infant Mortality
Infant mortality—death during the first year after birth—is now relatively rare in
the industrialized world, thanks to decades of improvements in public health and
general economic levels. In the United States, the 2010 infant mortality rate was 6.14
deaths per 1000 live births, the lowest in U.S. history (Miniño & Murphy, 2012).
colic n excessive, inconsolable crying by
a young infant for no apparent reason
infant mortality n death during the first
year after birth

t h E n E w B O R n I n F A n t n 75
Although the U.S. infant mortality rate is at an all­time
low in absolute terms, it is high compared with that of other
industrialized nations. (Table 2.3 shows where the United
States’ infant mortality rate stood relative to the rates of a se­
lection of developed countries in 2008.) The relative ranking
of the United States has generally gotten worse over the past
several decades, because the infant mortality rates in many
other countries have had a higher rate of improvement.
The rates of infant mortality are starkly different for sub­
sets of the U.S. population. African American infants are
more than twice as likely to die before their first birthday
as European American infants are. Indeed, the infant mor­
tality rate for African Americans is similar to the rates ob­
served in many underdeveloped countries.
Why do so many babies die in the United States—the
richest country in the world? Why are African American
infants’ chances of survival so much poorer than those of
White American infants? There are many reasons, most
having to do with poverty. For example, many low­ income
mothers­to­be, including a disproportionate number of Af­
rican Americans, have no health insurance and thus lim­
ited access to good medical and prenatal care (Cohen &
Martinez, 2006). In contrast, the countries that rank above
the United States with respect to infant mortality usually
provide government­sponsored health care that guarantees
prenatal care at low or minimal cost.
In less developed countries, especially those suffering from a breakdown in social
organization due to war, famine, major epidemics, or persistent extreme poverty, the
infant mortality rates can be staggering. In countries like Afghanistan, Mali, and
Somalia, for example, roughly one of every 10 infants dies before age 1 (Central
Intelligence Agency, 2012).
TABLE 2.3
Infant Mortality rates (IMr)* for Selected Developed Nations
with Lower rates than Those of the United States, 2008
Country Infant
Mortality Rate
Country Infant
Mortality Rate
Luxembourg 1.8 France 3.8
Slovenia 2.1 Israel 3.8
Iceland 2.5 Netherlands 3.8
Sweden 2.5 Denmark 4.0
Japan 2.6 Switzerland 4.0
Finland 2.6 Australia 4.1
Norway 2.7 Korea 4.7
Greece 2.7 United Kingdom 4.7
Czech Republic 2.8 New Zealand 4.9
Ireland 3.0 Estonia 5.0
Portugal 3.3 Hungary 5.6
Belgium 3.4 Poland 5.6
Germany 3.5 Canada 5.7
Spain 3.5 Slovak Republic 5.9
Austria 3.7 United States 6.6
Italy 3.7
*Infant Deaths per 1000 Live Births
Source: Adapted from Heisler, 2012
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afghanistan has one of the highest infant
mortality rates in the world. among the
causes are extreme poverty, poor nutrition,
and poor sanitation. The great majority of
the population lacks access to clean water,
leading to a great many infant deaths
related to dysentery, severe diarrhea, and
other illnesses.

76 n chapTer 2 PREnAtAl DEvElOPMEnt AnD thE nEwBORn PERIOD
Low Birth Weight
The average newborn in the United States weighs 7½ pounds (most are between 5½
and 10 pounds). Infants who weigh less than 5½ pounds (2500 grams) at birth are
considered to be of low birth weight (LBW ). Some LBW infants are premature, or
preterm; that is, they are born at 35 weeks after conception or earlier, instead of the
normal term of 38 weeks. Other LBW infants are referred to as small for gestational
age: they may be either preterm or full­term, but they weigh substantially less than is
normal for their gestational age, which is based on weeks since conception.
Slightly more than 8% of all U.S. newborns are of LBW (Martin et al., 2012). The
rate for African American LBW newborns is nearly twice as high (13.6%), and ap­
proaches the LBW rate observed in developing countries (16.5%) (United Nations
Children’s Fund and World Health Organization, 2004). As a group, LBW new­
borns have a heightened level of medical complications, as well as higher rates of
neurosensory deficits, more frequent illness, lower IQ scores, and lower educational
achievement. Very LBW babies (those weighing less than 1500
grams, or 3.3 pounds) are particularly vulnerable; these infants
accounted for 1.45% of live births in the United States in 2009
(Martin et al., 2011).
There are numerous causes of LBW and prematurity, includ­
ing many of the infant­mortality risk factors discussed earlier.
Another cause is the skyrocketing rate of twin, triplet, and other
multiple births as a result of the development of increasingly
successful treatments for infertility. (The use of fertility drugs
typically results in multiple eggs being released during ovulation;
the use of in vitro fertilization [IVF] usually involves the place­
ment of multiple laboratory­fertilized embryos in the uterus.) In
1980, 1 in every 53 infants born in the United States was a twin;
in 2009, 1 in every 30 infants was a twin (Martin, Hamilton, &
Osterman, 2012). The numbers for higher­order births (triplets
and up) have also increased dramatically in recent years. This is
a concern because the rates of LBW among multiples are quite
high: 56% for twins and higher than 90% for triplets and above
(Martin et al., 2011). (Box 2.5 discusses some of the challenges
faced by parents of LBW infants.)
Long-term outcomes What outcome can be expected for LBW newborns who
survive? This question becomes increasingly important as newborns of ever lower
birth weights—some as low as 800 grams (about 1.76 pounds)—are kept alive by
modern medical technology. The answer includes both bad news and good news.
The bad news is that, as a group, children who were LBW infants have a
higher incidence of developmental problems: the lower their birth weight, the
more likely they are to have persistent difficulties (e.g., Muraskas, Hasson, &
Besinger, 2004). They suffer from somewhat higher levels of hearing, language,
and cognitive impairments. In preschool and elementary school, they are more
likely to be distractible and hyperactive and to have learning disabilities. This
group is also more likely to experience a variety of social problems, including
poor peer and parent–child relations (Landry et al., 1990). Finally, adolescents
who were LBW babies are less likely than their siblings to complete high school
(Conley & Bennett, 2002). This result holds even within twin pairs; the twin
with higher birth weight is more likely to complete high school than is his or her
smaller co­twin (Black et al., 2007).
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These newborns were among 5503 triplet
births in the United States in 2010. That
year, there were also 313 quadruplet births
and 37 quintuplet and other higher-order
births.
low birth weight (LBW) n a birth
weight of less than 5½ pounds (2500
grams)
premature n any child born at 35 weeks
after conception or earlier (as opposed to
the normal term of 38 weeks)
small for gestational age n babies
who weigh substantially less than is
normal for whatever their gestational age

t h E n E w B O R n I n F A n t n 77
FIGURE 2.23 Small miracles Shown here is (a) one of the smallest newborns ever to survive
and (b) the same child at 14 years of age. Born in 1989 after just 27 weeks of gestation, Madeline
weighed a mere 9.9 ounces—approximately the equivalent of three bars of soap. extremely LBW
infants tend to suffer serious disabilities, but Madeline is remarkably healthy, other than being a bit
small for her age and having asthma. She entered high school as an honor student and enjoys playing
her violin and rollerblading.
(a) (b)
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The good news is that the majority of LBW children turn out quite well. The
negative effects of their birth status gradually diminish, with children who were
slightly to moderately underweight as newborns generally ending up within the
normal range on most developmental measures (Kopp & Kaler, 1989; Liaw &
Brooks­Gunn, 1993; Meisels & Plunkett, 1988; Vohr & Garcia­Coll, 1988). Fig­
ure 2.23 depicts a particularly striking example of this fact (Muraskas et al., 2004).
Indeed, one recent follow­up study of extremely LBW infants (,1000 grams)
found that by 18 to 22 months of age, 16% were unimpaired and 22% were only
mildly impaired (Gargus et al., 2009).
Intervention programs What can be done to help an LBW infant overcome his
or her poor start in life? A variety of intervention programs for LBW newborns
offer a prime example of our theme about the role of research in improving the wel­
fare of children. In many of them, parents are active participants, a marked change
from past practice. Hospitals formerly did not allow parents to have any contact
with their LBW infants, mainly because of fear of infection. Parents are now en­
couraged to have as much physical contact and social interaction with their hospi­
talized infant as the baby’s condition allows.
One widely implemented intervention for hospitalized newborns is based on the
idea that being touched—cuddled, caressed, and carried—is a vital part of a new­
born’s life. Many LBW infants experience little stimulation of this kind because
of the precautions that must be taken with them, including keeping them in spe­
cial isolettes, hooked up to various life­support machines. To compensate for this
lack of everyday touching experience, Field and her colleagues (Field, 2001; Field,
Hernandez­Reif, & Freedman, 2004) developed a special therapy that involves

78 n chapTer 2 PREnAtAl DEvElOPMEnt AnD thE nEwBORn PERIOD
BOX 2 .5: applications
PARENTING A LOW-BIRTH-WEIGHT BABY
Parenthood is challenging under the best of
circumstances, but it is especially so for the
parents of a preterm or LBW baby. First, they
have to accept their disappointment over the
fact that they do not have the perfect baby
they had hoped for, and they may also have
to cope with feelings of guilt (“What did I
do wrong?”), inadequacy (“How can I possi-
bly take care of such a tiny, fragile baby?”),
and fear (“Will my baby survive?”). In addi-
tion, caring for an LBW baby can be espe-
cially time-consuming and stressful and, if
the infant requires extended treatment, very
expensive.
While all new parents have a great deal
to learn about caring for their infants, par-
ents of an LBW baby face special challenges
from the outset. In the hospital, they need to
learn how to interact successfully with their
fragile baby, who may be confined to an iso-
lette and hooked up to life-support equip-
ment. When their infant comes home, they
may have to cope with a baby who is fairly
passive and unresponsive, while being care-
ful not to overstimulate the infant in an effort
to elicit some response (Brazelton, Nugent,
& Lester, 1987; Patteson & Barnard, 1990).
LBW infants also tend to be fussier than the
average baby and more difficult to soothe
when they become upset (Greene, Fox, &
Lewis, 1983). To compound matters, they
often have a high-pitched cry that is particu-
larly unpleasant (Lester et al., 1989).
Another problem for parents is the fact
that LBW infants have more trouble falling
asleep, waking up, and staying alert than
do infants of normal birth weight, and their
feeding schedules are less regular (DiVitto &
Goldberg, 1979; Meisels & Plunkett, 1988).
Thus, it takes longer for the baby to get on
a predictable schedule, making the parents’
lives more hectic.
Parents of a preterm infant also need to
understand that their baby’s early develop-
ment will not follow the same timetable as a
full-term infant’s: developmental milestones
will be delayed, often linked more tightly to
gestational age at birth than to chronologi-
cal age after birth. For example, their infant
will not begin to smile at them at around 6
weeks of age, the time when full-term in-
fants usually reach this milestone. Instead,
they may have to wait several more weeks for
their baby to look them in the eye and break
into a heart-melting smile. Thus, preterm
infants are potentially more challenging to
care for while being less rewarding to inter-
act with. One consequence is that children
who were born preterm are more likely to be
victims of parental child abuse than are full-
term infants (e.g., Spencer et al., 2006).
One step that can be helpful to parents of
an LBW or preterm infant is learning more
about infant development. One intervention
program trained mothers—in the hospital
and after returning home—to interpret their
preterm babies’ signals (Achenbach et al.,
1990). When tested at age 7 years, their
children showed significantly better cogni-
tive skills than those of a comparison group
of LBW children whose parents did not re-
ceive training.
In a more recent longitudinal study, re-
searchers randomly assigned a group of
mothers of preterm infants to either receive
an intervention focused on increasing paren-
tal self-confidence and responsiveness or to
be in a control group that received no inter-
vention (Nordhov et al., 2012). At age 5, a
comparison of behavioral outcomes for the
children in each group (as rated by parents
and preschool teachers) indicated that the
children whose mothers experienced the
intervention had fewer behavior problems
than did the children whose mothers did not
experience the intervention. This was par-
ticularly the case in the areas of aggressive
behavior and attention deficits, which are
often associated with preterm birth. This re-
sult is especially informative because the
study’s randomized control design means
that the findings cannot be readily explained
by preexisting differences among the infants
and their families.
In addition, any parent who is trying to
deal with an LBW baby or an infant with
other problems would do well to seek social
support—from a spouse or partner, other
family members, friends, or a formal sup-
port group. One of the best-documented
phenomena in psychology is that we all
cope better with virtually any life problem
when we have support from other people. In-
deed, one potentially important component
of the successful intervention described in
the preceding paragraph is that it included
support sessions, in the hospital and during
home visits, designed to encourage parents
to talk about their experiences and express
their feelings.
parents of an LBW baby usually have to wait longer to experience the joy
of their child’s first social smile.
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t h E n E w B O R n I n F A n t n 79
massaging LBW babies and flexing their arms and legs (Figure
2.24). LBW babies who receive this therapy are more active and
alert and gain weight faster than those who are not massaged. As a
consequence, they get to go home earlier. Recent results also suggest
that having parents sing to their LBW newborns during their stay
in the hospital similarly improves the newborns’ health, while also
calming parents’ fears (Loewy et al., 2013).
Many intervention programs for LBW newborns extend beyond
their hospital stay, some for several years (e.g., Ramey & Campbell,
1992). The potential of such interventions was highlighted by the
Infant Health and Development Project (IHDP), which involved
985 children in eight major U.S. cities. This program was especially
well designed. For one thing, the infants were randomly assigned
to either the intervention group or the control group. For another,
all the children were provided good health care, which ensured that
this crucial factor could not affect the outcome of the research. The
intervention lasted for 3 years and included an intensive early­childhood education
program, as well as home visits that, among other things, encouraged the parents’
continued participation in the program.
Repeated assessments of the children in this study have consistently revealed
a positive effect of intervention, at least for infants who weighed more than 2000
grams. At 3 years of age, the intervention group had an advantage of 14 IQ points
over the control group, although the difference was larger for the LBW children
who had been relatively heavier at birth—2000 to 2500 grams versus less than 2000
grams. In follow­ups at 5 and 8 years of age, the intervention group continued to
show advantages, though these were limited to those participants who had weighed
more than 2000 grams at birth. In the most recent assessment, when the partici­
pants were 18 years old, differences favoring the intervention group—better aca­
demic performance and fewer behavior problems—were still observed, but, again,
only for those teenagers who had been the heavier LBW newborns (McCormick
et al., 2006). The researchers concluded that their results provide support for early
intervention to promote the development of at­risk LBW infants, but they also
noted that such interventions are less likely to be successful with children who were
extremely small newborns.
The IHDP story illustrates three important general points relevant to inter­
vention efforts designed for high­risk infants. First, many intervention programs
produce gains, but often those gains are relatively modest and diminish over time.
Second, the success of any intervention depends on the initial health status of the
infant. Like the IHDP, many programs for LBW babies have been most beneficial
to those infants who are less tiny at birth. This fact is cause for concern, as modern
medical technology makes it increasingly possible to save the lives of ever­smaller
infants who have a high risk of permanent, serious impairment. The third point is
the importance of cumulative risk: the more risks the infant endures, the lower the
chances of a good outcome. Because this principle is so important for all aspects of
development, we examine it in greater detail in the following section.
Multiple-Risk Model
Risk factors tend to occur together. For example, a woman who is so addicted to
alcohol, cocaine, or heroin that she continues to abuse the substance even though
she is pregnant is likely to be under a great deal of stress and unlikely to eat well,
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FIGURE 2.24 Infant massage every-
body enjoys a good massage, but hospital-
ized newborns particularly benefit from extra
touching.

80 n chapTer 2 PREnAtAl DEvElOPMEnt AnD thE nEwBORn PERIOD
take vitamins, earn a good income, seek prenatal care, have a strong social support
network, or take good care of herself in other ways. Furthermore, whatever the cu­
mulative effects of these prenatal risk factors, they will likely be compounded after
birth by the mother’s continuation of her unhealthy lifestyle and by her resulting
inability to provide good care for her child (e.g., Weston et al., 1989).
As you will see repeatedly throughout this book, a negative developmental
outcome—whether in terms of prenatal or later development—is more likely when
there are multiple risk factors. In a classic demonstration of this fact, Michael Rutter
(1979) reported a heightened incidence of psychiatric problems among English
children growing up in families with four or more risk factors (including marital
distress, low SES, paternal criminality, and maternal psychiatric disorder) (Figure
2.25). Thus, the likelihood of developing a disorder is slightly elevated for the child
of parents who fight a lot; but if the child’s family is also poor, the father engages
in criminal behavior, and the mother suffers from emotional problems, the child’s
risk is multiplied nearly tenfold. Similar risk patterns have been reported for IQ
(Sameroff et al., 1993) and social­emotional competence (Sameroff et al., 1987).
Poverty as a Developmental Hazard
Because it is such an important point, we cannot emphasize enough that the ex­
istence of multiple risks is strongly related to SES. Consider some of the factors
we have discussed that are known to be dangerous for fetal development: inade­
quate prenatal care, poor nutrition, illness, emotional stress, cigarette smoking, drug
abuse, and exposure to environmental and occupational hazards. All these factors
are more likely to be experienced by a woman living below the poverty line than
by a middle­class woman. It is no wonder, then, that on the whole, the outcome
of pregnancy is less positive for infants of lower­SES parents than for babies born
to middle­class parents (Kopp, 1990; Minde, 1993; Sameroff, 1986). Nor should
it be surprising that among LBW infants, the eventual developmental outcome is
poorer for those in lower­SES families (Drillien, 1964; Gross et al., 1997; Kalmár,
1996; Largo et al., 1989; Lee & Barratt, 1993; McCarton et al., 1997; Meisels &
Plunkett, 1988).
An equally sad fact is that in many countries, minority families are overrepre­
sented in the lowest SES levels. According to a study by the National Center for
Children in Poverty, in 2011, 22% of all U.S. children lived in families whose in­
come placed them below the poverty line ($22,350 for a family of four in that year).
However, among African American and Hispanic children, the percent living in
poverty was 39% and 34%, respectively (Addy, Engelhardt, & Skinner, 2013).
Thus, their SES places many minority fetuses, newborns, and children at increased
risk for developmental difficulties.
Risk and Resilience
There are, of course, individuals who, faced with multiple and seemingly over­
whelming developmental hazards, nevertheless do well. In studying such children,
researchers employ the concept of developmental resilience (Garmezy, 1983;
Masten, Best, & Garmezy, 1990; Sameroff, 1998). Resilient children—like those
in the Kauai study discussed in Chapter 1—often have two factors in their favor:
(1) certain personal characteristics, especially intelligence, responsiveness to others,
and a sense of being capable of achieving their goals; and (2) responsive care from
someone.
developmental resilience n successful
development in spite of multiple and
seemingly overwhelming developmental
hazards
0
Number of risk factors
1 2 3 4+
0%
5%
10%
15%
20%
25%
FIGURE 2.25 Multiple risk factors
children who grow up in families with mul-
tiple risk factors are more likely to develop
psychiatric disorders than are children from
families with only one or two problematic
characteristics (rutter, 1979).

C h A P t E R S U M M A R Y n 81
chapter summary:
Prenatal Development
n Nature and nurture combine forces in prenatal development.
Much of this development is generated by the fetus itself,
making the fetus an active player in its own progress. Substan­
tial continuity exists between what goes on before and after
birth in that infants demonstrate the effects of what has hap­
pened to them in the womb.
n Prenatal development begins at the cellular level with
conception, the union of an egg from the mother and a
sperm from the father to form a single­celled zygote. The
zygote multiplies and divides on its way through a fallopian
tube.
n The zygote undergoes the processes of cell division, cell migra­
tion, cell differentiation, and cell death. These processes con­
tinue throughout prenatal development.
n When the zygote becomes implanted on the uterine wall, it
becomes an embryo. From that point, it is dependent on the
mother to obtain nourishment and oxygen and to get rid of
waste products through the placenta.
n Fetal behavior begins 5 or 6 weeks after conception with
simple movements, undetected by the mother, that become
increasingly complex and organized into patterns. Later,
the fetus practices behaviors vital to independent living,
including swallowing and a form of intrauterine “breathing.”
n The fetus experiences a wealth of stimulation both from
within the womb and from the external environment.
The fetus learns from this experience, as demonstrated by
studies showing that both fetuses and newborns can dis­
criminate between familiar and novel sounds, especially in
speech, and exhibit persistent taste preferences developed in
the womb.
n There are many hazards to prenatal development. The most
common fate of a fertilized egg is spontaneous abortion
(miscarriage). A wide range of environmental factors can be
In summary, development is highly complex, from the moment of conception
to the moment of birth. As you will see throughout this book, that complexity
continues over the ensuing years. Although early events and experiences can pro­
foundly affect later development, developmental outcomes are never a foregone
conclusion.
review:
The experience of newborn infants is mediated by internal states of arousal, ranging from
deep sleep to intense crying, with large individual differences in the amount of time spent in
the different states. Newborns spend roughly half their time asleep, but after early infancy,
the amount of sleep declines steadily over many years. Researchers believe that the large
proportion of sleep time that newborns spend in REM sleep is important for the development
of the visual system and brain. Infants’ crying is a particularly salient form of behavior for
parents, and it generally elicits attention and caretaking. Effective soothing techniques pro-
vide moderately intense, continuous, or repetitive stimulation. How parents respond to their
young infant’s distress is related to later crying.
Negative outcomes of pregnancy are higher for minorities and for families living in pov-
erty. The United States has higher rates of infant mortality than do many other developed
nations. Just more than 8% of all infants born in the United States are LBW. Although most
will suffer few lasting effects, the long-term outcome of extremely LBW babies is often prob-
lematic. Several large-scale intervention programs have successfully improved the outcome
of LBW infants.
According to the multiple-risk model, the more risks that a fetus or child faces, the more
likely the child is to suffer from a variety of developmental problems. Low SES is associated
with many developmental hazards. Despite facing multiple risks, many children nevertheless
show remarkable resiliency and thrive.

82 n chapTer 2 PREnAtAl DEvElOPMEnt AnD thE nEwBORn PERIOD
Critical Thinking Questions
1. A recent cartoon showed a pregnant woman walking down a
street carrying an MP3 player with a set of very large head­
phones clamped around her protruding abdomen. What
point was it making? What research might have provided
the basis for the woman’s behavior, and what assumptions is
she making about what the result might be? If you or your
partner were pregnant, do you think you would do something
like this?
2. We hear a great deal about the terrible and tragic effects that
illegal drugs like cocaine and diseases like AIDS can have on
fetal development. But what two maternal behaviors associ­
ated with prenatal harm are actually the most common in the
United States today, and what are some of the effects they
can have?
3. Suppose you were in charge of a public health campaign to
improve prenatal development in the United States and you
could focus on only one factor. What would you target and
why?
4. Describe some of the cultural differences that exist in beliefs
and practices with respect to conception, pregnancy, and
childbirth. Is there any practice of another culture that
appeals to you more than the practices with which you are
familiar?
5. Are you more encouraged or more discouraged by the
results of intervention programs such as the IHDP?
What would it take to make their gains larger and longer
lasting?
6. Speculate on why the infant mortality rate in the United
States has steadily gotten worse compared with that of other
countries.
7. Explain the basic idea of the multiple­risk model and how it
relates to poverty in terms of prenatal development and birth
outcomes.
hazardous to prenatal development. These include teratogens
from the external world and certain maternal characteris­
tics, such as age, nutritional status, physical health, behavior
(especially the use of legal or illegal drugs), and emotional
state.
The Birth Experience
n Approximately 38 weeks after conception, the baby is ready to
be born. Usually, the behavior of the fetus helps to initiate the
birth process.
n Being squeezed through the birth canal has several beneficial
effects on the newborn, including preparing the infant to take
his or her first breath.
n Cultural practices surrounding childbirth vary greatly and
are in part related to the goals and values emphasized by the
culture.
The Newborn Infant
n Newborns’ states of arousal range from deep sleep to active
crying.
n The amount of time infants spend in the different arousal
states varies greatly, both across individuals and across
cultures.
n REM sleep seems to compensate for the lack of visual stimu­
lation that results from the darkness of the womb, and for the
fact that newborns spend much of their time with their eyes
shut, asleep.
n The sound of a baby crying can be very aversive, and adults
employ many strategies to soothe distressed infants.
n The infant mortality rate in the United States is high rela­
tive to that of other developed countries. It is much higher for
babies born to low­SES parents.
n Infants born weighing less than 5½ pounds (2500 grams)
are referred to as being of low birth weight. LBW infants are
at risk for a variety of developmental problems, and the
lower the birth weight, the greater the risk of lasting
difficulties.
n A variety of intervention programs have been designed to
improve the course of development of LBW babies, but the
success of such programs depends very much on the number of
risk factors that threaten the baby.
n The multiple­risk model refers to the fact that infants with a
number of risk factors have a heightened likelihood of con­
tinued developmental problems. Poverty is a particularly insid­
ious risk to development, in part because it is associated with
numerous negative factors.
n Some children display resilience even in the face of sub­
stantial challenges. Resilience seems to result from cer­
tain personal characteristics and from responsive care from
someone.

C h A P t E R S U M M A R Y n 83
Key Terms
amniotic sac, p. 48
apoptosis, p. 46
cephalocaudal development, p. 48
colic, p. 74
conception, p. 42
developmental resilience, p. 80
dose–response relation, p. 59
embryo, p. 45
embryonic stem cells, p. 45
epigenesis, p. 42
fetal alcohol spectrum disorder (FASD), p. 62
fetus, p. 45
fraternal twins, p. 47
gametes (germ cells), p. 42
habituation, p. 54
identical twins, p. 47
infant mortality, p. 74
low birth weight (LBW), p. 76
meiosis, p. 42
mitosis, p. 45
neural tube, p. 47
non­REM sleep, p. 70
phylogenetic continuity, p. 46
placenta, p. 48
premature, p. 76
rapid eye movement (REM) sleep, p. 70
sensitive period, p. 57
small for gestational age, p. 76
state, p. 70
sudden infant death syndrome (SIDS), p. 61
swaddling, p. 73
teratogen, p. 57
umbilical cord, p. 48
zygote, p. 44

84
T I L LY W I L L I S , Waiting, 2005 (oil on canvas)
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Biology and Behavior
n Nature and Nurture
Genetic and Environmental Forces
Box 3.1: Applications Genetic Transmission of Disorders
Behavior Genetics
Box 3.2: Individual Differences Identical Twins
Reared Apart
Review
n Brain Development
Structures of the Brain
Developmental Processes
Box 3.3: A Closer Look Mapping the Mind
The Importance of Experience
Brain Damage and Recovery
Review
n The Body: Physical Growth and
Development
Growth and Maturation
Nutritional Behavior
Review
n Chapter Summary
chapter 3:

86
S
everal years ago, one of your authors received a call from the police. A
city detective wanted to come by for a chat about some street and traffic
signs that had been stolen—and also about the fact that one of the culprits
was the author’s 17-year-old son. In an evening of hilarious fun and poor
judgment, the son, along with two friends, had stolen more than a dozen
city signs and then concealed them in the family attic. His upset parents wondered
how their sweet, sensitive, kind, soon-to-be Eagle Scout son (who can be seen in
his innocent days on pages 137 and 594) could have failed to foresee the conse-
quences of his actions.
Many parents have similarly wondered how their once-model children could
have morphed into thoughtless, irresponsible, self-absorbed, impolite, bad-
tempered individuals simply by virtue of entering adolescence. Parents are not
the only ones surprised by the change in the behavior of their offspring: teen-
agers themselves are often taken aback and mystified as to what has come over
them. One 14-year-old girl lamented: “Sometimes, I just get overwhelmed now. . . .
There’s all this friend stuff and school and how I look and my parents. I just go in
my room and shut the door. . . . I don’t mean to be mean, but sometimes I just have
to go away and calm down by myself.” And a 15-year-old boy expressed similar
concerns: “I get in trouble a lot more now, but it’s for stuff I really didn’t mean. . . .
I forget to call home. I don’t know why. I just hang out with friends, and I get in-
volved with that and I forget. Then my parents get really mad, and then I get really
mad, and it’s a big mess” (Strauch, 2003).
New insights into these often abrupt developmental changes have come through
research into the biological underpinnings of behavioral development. Researchers
now suspect that many of the behavioral changes that are distressing both to ado-
lescents and their parents may be related to dramatic changes in brain structure and
functioning that occur during adolescence. In addition, there is growing evidence
that some genetic predispositions do not emerge until adolescence and that they
may contribute to these seemingly abrupt developmental changes.
Understanding the biological underpinnings of behavioral development is, of
course, essential to understanding development at any point in the life span. The
focus of this chapter is on the key biological factors that are in play from the mo-
ment of conception through adolescence, including the inheritance and influence
of genes, the development and early functioning of the brain, and important as-
pects of physical development and maturation. Every cell in our bodies carries the
genetic material that we inherited at our conception and that continues to influ-
ence our behavior throughout life. Every behavior we engage in is directed by our
brain. Everything we do at every age is mediated by a constantly changing physical
body—one that changes very rapidly and dramatically in the first few years of life
and in adolescence, but more slowly and subtly at other times.
Several of the themes that were set out in Chapter 1 figure prominently in this
chapter. Issues of nature and nurture, as well as individual differences among children,
are central throughout this whole chapter and especially the first section, which fo-
cuses on the interaction of genetic and environmental factors in development. Mech-
anisms of change are prominent in our discussions of the developmental role of genetic
factors and of the processes involved in the relationship between brain functioning
and behavior. Continuity in development is also highlighted throughout the chapter.
We again emphasize the activity-dependent nature of developmental processes and
the role of the active child in charting the course of his or her own development.
Themes
n Nature and Nurture
n The Active Child
n Continuity/Discontinuity
n Mechanisms of Change
n Individual Differences
n Research and Children’s
Welfare

N A T u R E A N D N u R T u R E n 87
Nature and Nurture
Everything about you—from your physical structure, intellectual capacity, and per-
sonality characteristics to your preferences in hobbies and food—is a joint conse-
quence of the interaction between the genetic material you inherited from your
parents and the environments you have experienced from conception to the pres-
ent moment. These two factors—heredity and environment—work in concert to
influence both the ways in which you are like other people and the ways in which
you are unique.
Long before there was any understanding of the principles of heredity, people
were aware that some traits and characteristics “run in families” and that this ten-
dency was somehow related to procreation. For as long as there have been domes-
ticated animals, for example, farmers have practiced selective breeding to improve
certain characteristics of their livestock, such as the size of their horses and the milk
yield of their goats, cows, or yaks. People have also long been aware that the environ-
ment plays a role in development—that a nutritious diet, for example, is necessary
for livestock to produce a good milk supply or fine-quality wool. When scientists
first began to investigate the contributions of heredity and environment to develop-
ment, they generally emphasized one factor or the other as the prime influence—
heredity or environment, nature or nurture. In nineteenth-century En gland, for
example, Francis Galton (1869/1962), a cousin of Charles Darwin, identified men
who had achieved “eminence” in a variety of fields and concluded that talent runs
in families, because very close relatives of an eminent man (his father, brother, son)
were more likely to be high achievers themselves than were less close relatives.
Among Galton’s cases of closely related eminent men were John Stuart Mill and
his father, both respected English philosophers. However, Mill himself pointed out
that most of Galton’s eminent men were members of well-to-do families. In his
view, the relation between the achievement of these eminent men and their kinship
had less to do with biological ties than with the fact that they were similar in eco-
nomic well-being, social status, education, and other advantages and opportunities.
The phenomenal athletic ability of tennis
greats Venus and Serena Williams is almost
certainly due to the combination of nature—
the genes they inherited from their par-
ents—and nurture—the extensive coaching
they received from their father and the tire-
less emotional support provided by their
mother.PA
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88 n chapTer 3 BIOLOGY AND BEHAVIOR
In short, according to Mill, Galton’s subjects rose to eminence more because of en-
vironmental factors than hereditary ones.
Our modern understanding of how characteristics are transmitted from parent
to offspring originated with insights achieved by Gregor Mendel, a nineteenth-
century Austrian monk who observed distinct patterns of inheritance in the pea
plants that he cross-bred in his monastery garden. Some aspects of these inheri-
tance patterns were later discovered to occur in all living things (see pages 92–93).
A much deeper understanding of how genetic influences operate came with James
Watson and Francis Crick’s 1953 identification of the structure of DNA, the basic
component of hereditary transmission.
Since that landmark discovery, enormous progress has been made in deciphering
the genetic code. Researchers have mapped the entire genome—the complete set
of genes—of myriad species of plants and animals, including chickens, mice, chim-
panzees, and humans, and even several extinct species,
including our closest evolutionary relative, Neander-
thals (R. E. Green et al., 2010). In 2010, a consortium
of geneticists began working to sequence the genomes
of 10,000 vertebrate species (Lander, 2011), the expec-
tation being that examining the genomes of such a di-
verse set of species will provide knowledge not only
about those species but also about human evolution
and the way genes function. Comparisons of the ge-
nomes of various species have already revealed much
about our human genetic endowment, and they have
provided numerous surprises.
One surprise was the number of genes that humans
have: the current estimate of around 21,000 genes is
far fewer than previous estimates, which ranged from
35,000 to more than 100,000 genes (Clamp et al.,
2007). A second major surprise was that most of those
genes are possessed by all living things. We humans
share a large proportion of our genes with bears, barnacles, beans, and bacteria. Most
of our genes are devoted, in decreasing order, to making us animals, vertebrates,
mammals, primates, and—finally—humans. In the next section, we will look at a
third surprise, one that may turn out to be a blockbuster.
As researchers have achieved better understanding of the role of hereditary fac-
tors in development, they have also come to appreciate the limits of what these
factors can account for on their own. Similarly, as knowledge has grown concern-
ing the influence of experience on development, it has become clear that experience
alone rarely provides a satisfactory account. Development results from the close and
continual interplay of nature and nurture—of genes and experience—and this in-
terplay is the focus of the following section.
Genetic and Environmental Forces
The interplay of genes and experience is exceedingly complex. To simplify our dis-
cussion of interactions among genetic and environmental factors, we will organize
it around the model of hereditary and environmental influences shown in Figure
3.1. Three key elements of the model are the genotype—the genetic material an
individual inherits; the phenotype—the observable expression of the genotype,
including both body characteristics and behavior; and the environment—every
©
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“We think it has something to do with your genome.”
genome n the complete set of genes of
any organism
genotype n the genetic material an indi-
vidual inherits
phenotype n the observable expres-
sion of the genotype, including both body
characteristics and behavior
environment n every aspect of an indi-
vidual and his or her surroundings other
than genes

N A T u R E A N D N u R T u R E n 89
aspect of the individual and his or her surroundings (including prenatal experience)
other than the genes themselves.
These three elements are involved in five relations that are fundamental in the
development of every child: (1) the parents’ genetic contribution to the child’s
genotype; (2) the contribution of the child’s genotype to his or her own phenotype;
(3) the contribution of the child’s environment to his or her phenotype; (4) the in-
fluence of the child’s phenotype on his or her environment; and (5) the influence
of the child’s environment on his or her genotype. We will now consider each of
these relations in turn.
1. Parent’s Genotype–Child’s Genotype
Relation 1 involves the transmission of genetic material—chromosomes and
genes—from parent to offspring. You caught a glimpse of this process in Chapter
2, when we discussed the gametes (one from the mother and one from the father)
that conjoin at conception to create a zygote. The nucleus of every cell in the body
contains chromosomes, long threadlike molecules made up of two twisted strands
of DNA (deoxyribonucleic acid). DNA carries all the biochemical instructions
involved in the formation and functioning of an organism. These instructions are
“packaged” in genes, the basic unit of heredity in all living things. Genes are sec-
tions of chromosomes. More specifically, each gene is a segment of DNA that is the
code for the production of particular proteins. Some proteins are the building blocks
of the body’s cells; others regulate the cells’ functioning. Genes affect development
and behavior only through the manufacture of proteins: “DNA’s information trans-
lated into flesh and blood” ( J. S. Levine & Suzuki, 1993, p. 19).
But here is the blockbuster surprise we mentioned earlier: researchers have dis-
covered that genes—at least “genes” as they have been traditionally defined—make
up only about 2% of the human genome (Mouse Genome Sequencing Consortium,
2002). Much of the rest of our genome—once thought to be “junk” DNA—turns
out to play a supporting role in influencing genetic transmission by regulating the
activity of protein-coding genes (e.g., Mendes Soares & Valcárcel, 2006). Just how
much of this noncoding DNA is vital to functioning, and precisely how it works,
is, as of today, shrouded in mystery and controversy. Given the pace of genetic re-
search, however, tomorrow may be a different story.
human heredity Humans normally have a total of 46 chromosomes in the nu-
cleus of each cell, except egg and sperm cells. (Recall from Chapter 2 that, as a
result of the type of cell division that produces gametes, eggs and sperm each
GENOTYPE / Parent GENOTYPE / Child
1. Parent’s Genotype–Child’s Genotype
2. Child’s Genotype–Child’s Phenotype
3. Child’s Environment–Child’s Phenotype
4. Child’s Phenotype–Child’s Environment
5. Child’s Environment–Child’s Genotype
PHENOTYPE / Parent
ENVIRONMENT / Child
PHENOTYPE / Child
1
2
3
4
5
FIGURE 3.1 Development Development
is a combined function of genetic and envi-
ronmental factors. The five numbered rela-
tions are discussed in detail in the text.
chromosomes n molecules of DNA that
transmit genetic information; chromo-
somes are made up of DNA
DNA (deoxyribonucleic acid) n mol-
ecules that carry all the biochemical
instructions involved in the formation and
functioning of an organism
genes n sections of chromosomes that
are the basic unit of heredity in all living
things

90 n chapTer 3 BIOLOGY AND BEHAVIOR
contain only 23 chromosomes.) These 46 chromosomes are
actually 23 pairs (Figure 3.2). With one exception—the sex
chromosomes—the two members of each chromosome pair are
of the same general size and shape (roughly the shape of the
letter X). Furthermore, each chromosome pair carries, usually
at corresponding locations, genes of the same type—that is,
sequences of DNA that are relevant to the same traits. One
member of each chromosome pair was inherited from each
parent. Thus, every individual has two copies of each gene, one
on the chromosome inherited from the father and one on the
chromosome from the mother. Your biological children will
each receive half of your genes, and your grandchildren will
have one-quarter (just as you have half your genes in common
with each of your biological parents and one-fourth with each
grandparent).
Sex determination As noted, the sex chromosomes, which
determine an individual’s sex, are an exception to the general
pattern of chromosome pairs being the same size and shape
and carrying corresponding genes. Females have two identi-
cal, largish sex chromosomes, called X chromosomes, but males
have one X chromosome and one much smaller Y chromo-
some (so called because it has the shape of the letter Y ). Be-
cause a female has only X chromosomes, the division of her
germ cells results in all her eggs having an X. However, be-
cause a male is XY, half his sperm contain an X chromosome
and half contain a Y. For this reason, it is always the father who
determines the sex of offspring: if an X-bearing sperm fertil-
izes an egg, a female (XX) zygote results; if an egg is fertilized
by a Y-bearing sperm, the zygote is male (XY ). It is the pres-
ence of a Y chromosome—not the fact of having only one X
chromosome—that makes an individual male. A gene on the
Y chromosome encodes the protein that triggers the prenatal
formation of testes by activating genes on other chromosomes. Subsequently, the
testes produce the hormone testosterone, which takes over the molding of male-
ness ( Jegalian & Lahn, 2001).
Diversity and individuality As we have noted, genes guarantee that humans will
be similar to one another in certain ways, both at the species level (we are all bipedal
and have opposable thumbs, for example) and at the individual level (i.e., family
resemblances). Genes also guarantee differences at both levels. Several mechanisms
contribute to genetic diversity among people.
One such mechanism is mutation, a change that occurs in a section of DNA.
Some mutations are random, spontaneous errors; others are caused by environ-
mental factors. Most are harmful. Those that occur in germ cells can be passed
on to offspring; many inherited diseases and disorders originate from a mutated
gene. (Box 3.1 on pages 94–95 discusses the genetic transmission of diseases and
disorders.)
Occasionally, however, a mutation that occurs in a germ cell or early in prena-
tal development makes individuals more viable, that is, more likely to survive—
perhaps by increasing their resistance to some disease or by increasing their ability
sex chromosomes n the chromosomes
(X and Y) that determine an individual’s
gender
mutation n a change in a section of
DNA
FIGURE 3.2 Karyotype This color-
enhanced micrograph, called a karyotype,
shows the 23 pairs of chromosomes in a
healthy human male. as you can see, in
nearly all cases, the chromosomes of each
homologous pair are roughly the same size.
The notable exception is the sex chro-
mosomes (middle of bottom row): the Y
chromosome that determines maleness is
much smaller than the X chromosome. a
woman’s karyotype would contain two X
chromosomes.
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N A T u R E A N D N u R T u R E n 91
to adapt to some crucial aspect of their environment. Such mutations provide the
basis for evolution. This is because a person with the favorable mutated gene is
more likely to survive long enough to produce offspring, who, in turn, are likely to
possess the mutated gene, thus heightening their own chance of surviving and re-
producing. Across generations, these favorable genes proliferate in the gene pool
of the species.
A second mechanism that promotes variability among individuals is the random
assortment of chromosomes in the formation of egg and sperm. During germ-cell
division, the 23 pairs of chromosomes are shuffled randomly, with chance deter-
mining which member of each pair goes into each new egg or sperm. This means
that, for each germ cell, there are 223, or 8.4 million, possible combinations of chro-
mosomes. Thus, when a sperm and an egg unite, the odds are essentially zero that
any two individuals—even members of the same family—would have the same
genotype (except, of course, identical twins). Further variation is introduced by
the fact that when germ cells divide, the two members of a pair of chromosomes
sometimes swap sections of DNA. As a result of this process, referred to as cross-
ing over, some of the chromosomes that parents pass on to their offspring are con-
stituted differently from their own.
2. Child’s Genotype–Child’s Phenotype
We now turn to Relation 2 in Figure 3.1, the relation between one’s genotype and
one’s phenotype. Our examination of the genetic contribution to the phenotype be-
gins with a key fact: although every cell in your body contains copies of all the genes
you received from your parents, only some of those genes are expressed. At any
given time in any cell in the body, some genes are active (turned on), while others
are not. Some genes that are hard at work in neurons, for example, are totally at rest
in toenail cells. As you will see, there are several reasons for this.
Gene expression: Developmental changes Genes influence development and
behavior only when they are turned on, and human development proceeds nor-
mally, from conception to death, only if genes get switched on and off in the right
place, at the right time, and for the right length of time. Some genes are turned on
in only a few cells and for only a few hours and then are switched off permanently.
This pattern is typical during embryological development when, for example, the
genes that are turned on in certain cells lead them to specialize for arm, hand, and
fingerprint formation. Other genes are involved in the basic functioning of almost
all cells almost all the time.
The switching on and off of genes is controlled primarily by regulator genes.
The activation or inactivation of one gene is always part of a chain of genetic
events. When one gene is switched on, it causes another gene to turn on or off,
which has an impact on the status of yet other genes. Thus, genes never function
in isolation. Instead, they belong to extensive networks in which the expression of
one gene is a precondition for the expression of another, and so on. The continuous
switching on and off of genes underlies development throughout life, from the ini-
tial prenatal differentiation of cells to the gene-induced events of puberty to many
of the changes related to aging.
External factors can affect the switching on and off of genes. A dramatic exam-
ple is the effect of thalidomide on limb development (described in Chapter 2), in
which the sedative interferes with the functioning of genes underpinning normal
growth factors (Ito et al., 2010). Another example comes from the fact that early
These elvis impersonators look like elvis,
sneer like elvis, and even sing like elvis
(sort of). But they are not the King. The
probability that any two humans (other than
identical twins) have the same genotype is
essentially zero.
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crossing over n the process by which
sections of DNA switch from one chromo-
some to the other; crossing over promotes
variability among individuals
regulator genes n genes that control
the activity of other genes

92 n chapTer 3 BIOLOGY AND BEHAVIOR
visual experience is necessary for the normal development of the visual system, be-
cause it causes the switching on of certain genes, which, in turn, switch on other
genes in the visual cortex (Maya-Vetencourt & Origlia, 2012). The ramifications
of decreased visual experience are observed in cases of children with cataracts that
are not removed early in life, as discussed later in this chapter.
The fact that regulator genes can repeatedly switch other genes on and off in
different patterns means that a given gene can function multiple times in multiple
places during development. All that is required is that the gene’s expression be
controlled by different regulator genes at different times. This on-again, off-again
functioning of individual genes results in enormous diversity in genetic expression.
By analogy, consider the fact that this book is written with only 26 letters and prob-
ably only a few thousand different words made up of combinations of those letters.
The meaning comes from the order in which the letters occur, the order in which
they have been “switched on and off ” by the authors.
Gene expression: Dominance patterns Many of an individual’s genes are never
expressed; some others are only partially expressed. One reason for this is the fact
that about one-third of human genes have two or more different forms, known as
alleles. The alleles of a given gene influence the same trait or characteristic (e.g.,
eye color), but they contribute to different developmental outcomes (e.g., brown,
blue, hazel, gray eyes).
Let’s consider the simplest pattern of gene expression—the one discovered
by Mendel and referred to as the dominant–recessive pattern. The explanation for
this pattern (unknown to Mendel) is that some genes have only two alleles, one
of which is dominant and the other recessive. In this pattern, there are two pos-
sibilities: (1) a person can inherit two of the same allele—
two dominant or two recessive—and thus be homozygous
for the trait in question; or (2) the person can inherit two
different alleles—one dominant and the other recessive—
and thus be heterozygous for the trait. When an individual
is homozygous, with either two dominant or two recessive
alleles, the corresponding trait will be expressed. When an
individual is heterozygous for a trait, the instructions of the
dominant allele will be expressed (see Figure 3.3).
To illustrate, let us consider two traits of no importance
to human survival: the ability to roll one’s tongue lengthwise
and curliness of hair. If you can roll your tongue lengthwise
into the shape of a tube, then at least one, but not necessar-
ily both, of your parents must also possess this remarkable
but useless talent. From this statement (and Figure 3.3),
you should be able to figure out that tongue rolling is gov-
erned by a dominant allele. In contrast, if you have straight
hair, then both of your parents must carry an allele for this
trait, although it is possible that neither of them actually has
straight hair. This is because straight hair is governed by a recessive gene, and curly
hair is governed by a dominant gene.
The sex chromosomes present an interesting wrinkle in the story of dominance
patterns. The X chromosome carries roughly 1500 genes, whereas the much smaller
Y chromosome carries only about 200. Thus, when a female inherits a recessive al-
lele on the X chromosome from her mother, she is likely to have a dominant allele
on the chromosome from her father to suppress it, so she will not express the trait
B b
B B B
B = dominant gene for brown hair b = recessive gene for blond hair
b B b b b
B b
FIGURE 3.3 Mendelian inheritance
patterns pictured here are the Mendelian
inheritance patterns for the offspring of two
brown-haired parents who are both heterozy-
gous for hair color. The allele for brown hair
(B) is dominant, and that for blond hair (b)
is recessive. Note that these parents have
three chances out of four of producing chil-
dren with brown hair. They have two chances
in four of producing brown-haired children
who carry the gene for blond hair.
alleles n two or more different forms of
a gene
dominant allele n the allele that, if
present, gets expressed
recessive allele n the allele that is not
expressed if a dominant allele is present
homozygous n having two of the same
allele for a trait
heterozygous n having two different
alleles for a trait

N A T u R E A N D N u R T u R E n 93
in question. In contrast, when a male inherits the same recessive allele on the X
chromosome from his mother, he likely will not have a dominant allele from his
father to override it, so he will express the trait. This difference in sex-linked in-
heritance is one reason for the greater vulnerability of males described in Chapter
2 (Box 2.2): they are more likely to suffer a variety of inherited disorders caused by
recessive alleles on their X chromosome (see also Box 3.1).
Despite the traditional emphasis given to it, the dominant–recessive pattern of
inheritance, in which a single gene affects a particular trait, pertains to relatively
few human traits—such as hair color, blood type, abundance of body hair, and the
like—as well as to a large number of genetic disorders Much more commonly, a
single gene can affect multiple traits; both alleles can be fully expressed or blended
in heterozygous individuals; and some genes are expressed differently, depending
on whether they are inherited from the mother or from the father.
Inheritance patterns are vastly more complicated for most of the traits and
behaviors that are of primary interest to behavioral scientists. These traits, such
as shyness, aggression, thrill-seeking, and language learning, involve polygenic
inheritance, in which several different genes contribute to any given phenotypic
outcome. Gene-outcome linkages are particularly difficult to detect when many
genes are involved. For this reason, you should be skeptical whenever you encounter
newspaper headlines announcing the discovery of “a gene for” a complex human
trait or predisposition.
3. Child’s Environment–Child’s Phenotype
We now come to Relation 3 in our model—the impact of the environment on
the child’s phenotype. (Remember, the environment includes everything not in
the genetic material itself, including the variety of prenatal experiences discussed
in Chapter 2.) As the model indicates, the child’s observable characteristics re-
sult from the interaction between environmental factors and the child’s genetic
makeup.
Because of the continuous interaction of genotype and environment, a given
genotype will develop differently in different environments. This idea is expressed
by the concept of the norm of reaction (Dobzhansky, 1955), which refers to all the
phenotypes that could theoretically result from a given genotype in relation to all
the environments in which it could survive and develop. According to this concept,
for any given genotype developing in varying environments, a range of outcomes
would be possible. A child with a given genotype would probably develop quite dif-
ferently in a loving, supportive family than he or she would in an alienating, abusive
family. (Figure 3.4 offers a classic illustration of the norm of reaction in a genotype–
environment interaction.)
examples of genotype–environment interaction Genotype–environment in-
teractions can be studied directly by randomly assigning nonhuman animals with
known genotypes to be raised in a wide variety of environmental conditions. If
genetically identical animals develop differently in different environments, re-
searchers can infer that environmental factors must be responsible for the different
developmental outcomes. Scientists cannot, of course, randomly assign humans to
different rearing conditions, but there are powerful naturally occurring examples of
genotype–environment interactions for humans.
One such example is phenylketonuria (PKU), a disorder related to a defective
recessive gene on chromosome 12. Individuals who inherit this gene from both
polygenic inheritance n inheritance
in which traits are governed by more than
one gene
norm of reaction n all the phenotypes
that can theoretically result from a given
genotype in relation to all the environ-
ments in which it can survive and develop
phenylketonuria (PKU) n a disorder
related to a defective recessive gene on
chromosome 12 that prevents metabolism
of phenylalanine

94 n chapTer 3 BIOLOGY AND BEHAVIOR
Thousands of human disorders—many of
them extremely rare—are presently known to
have genetic origins. Although our discussion
here will focus on the behaviors and psycho-
logical symptoms associated with such dis-
orders, most of them also involve a variety
of physical symptoms, often including un-
usual physical appearance (e.g., distorted
facial features), organ defects (e.g., heart
problems), and atypical brain development.
These and other genetically based conditions
can be inherited in several different ways.
Dominant–Recessive Patterns
Many genetic disorders involve the
dominant–recessive pattern of inheritance,
occurring only when an individual has two
recessive alleles for the condition. To date,
more than 2850 such disorders have been
identified (Lander, 2011). Recessive-gene
disorders include PKU (discussed on pages
94 and 96) and sickle-cell anemia (dis-
cussed below), as well as Tay-Sachs disease,
cystic fibrosis, and many others. Disorders
that are caused by a dominant gene include
Huntington disease (a progressive and al-
ways fatal degenerative condition of the
brain) and neurofibromatosis (a disorder in
which nerve fibers develop tumors). A com-
bination of severe speech, language, and
motor difficulties that is common in a par-
ticular family in England has been traced to
a mutation of a single gene (referred to as
FOXP2) that acts in a dominant fashion (see
S. E. Fisher & Scharff, 2009).
In some cases, a single gene can have
both harmful and beneficial effects. One
such case is sickle-cell disease, in which
red blood cells are sickle-shaped rather
than round, diminishing their capacity to
transport oxygen. This disease, which can
be debilitating and sometimes fatal, affects
about 1 of every 500 African Americans. It
is a recessive-gene disorder, so individuals
who are homozygous for this trait (inheriting
two sickle-cell genes, one from each parent)
will suffer from the disease. Individuals who
are heterozygous for this trait (carrying one
normal and one sickle-cell gene) have some
abnormality in their blood cells but usually
experience no negative effects. In fact, if
they live in regions of the world—like West
Africa—where malaria is common, they ben-
efit, because the sickle cells in their blood
confer resistance against this deadly dis-
ease. In nineteenth-century Africa, malaria
came to be known as the “White man’s dis-
ease” because so many European explorers,
lacking the sickle-cell gene, died of it.
Note that even when the root cause of a
disorder is a single gene, it does not mean
that that one gene is responsible for all man-
ifestations of the disorder. The single gene
simply starts a cascade of events, turning on
and turning off multiple genes with effects
on many different aspects of the individual’s
subsequent development.
Polygenic Inheritance
Many common human disorders are believed
to result from interactions among multiple in-
herited genes, often in conjunction with envi-
ronmental factors. Among the many diseases
in this category are some forms of cancer and
heart disease, Type 1 and Type 2 diabetes,
and asthma. Psychiatric disorders, such as
schizophrenia, and behavior disorders, such
as attention-deficit hyperactivity disorder,
probably also involve multiple genes. More
than 1100 gene loci affecting common traits
and diseases have been identified to date,
due largely to continually improving methods
for genetic epidemiology (Lander, 2011).
Sex-Linked Inheritance
As mentioned in the text, some single-gene
conditions are carried on the X chromosome
and are much more common in males. (Fe-
males can inherit such conditions, but only
if they inherit the culprit recessive alleles on
both of their X chromosomes.) Sex-linked dis-
orders range from relatively minor problems,
like male-pattern baldness and red–green
color blindness, to very serious problems, in-
cluding hemophilia and Duchenne muscu-
lar dystrophy. Another sex-linked disorder is
fragile-X syndrome, which involves mutations
in the X chromosome and is the most com-
mon inherited form of intellectual disability.
Chromosomal Anomalies
Some genetic disorders originate with errors
in germ-cell division that result in a zygote
that has either more or less than the normal
complement of chromosomes. Most such
zygotes cannot survive, but some do. Down
syndrome most commonly originates when
the mother’s egg cells do not divide prop-
erly, and an egg that is fertilized contains an
extra copy of chromosome 21. The probabil-
ity of such errors in cell division increases
with age, with the incidence of giving birth
to a child with Down syndrome being mark-
edly higher for women older than 35. (In-
creased paternal age has also been linked to
the incidence of Down syndrome, though to
a lesser extent [De Souza, Alberman, & Mor-
ris, 2009; Hurles, 2012]). The boy pictured
on the next page shows some of the facial
features common to individuals with Down
syndrome, which is also marked by intellec-
tual disability (ranging from mild to severe),
a number of physical problems, and a sweet
temperament.
Other genetic disorders arise from extra
or missing sex chromosomes. For exam-
ple, Klinefelter syndrome, which affects
between 1 in 500 to 1000 males in the
United States, involves an extra X chromo-
some (XXY). The physical signs of this syn-
drome, which can include small testes and
elongated limbs, often go unnoticed, but in-
fertility is common. Turner syndrome, which
affects 1 in 2500 U.S. women, involves a
missing X chromosome (XO) and is usually
characterized by short stature, stunted sex-
ual development at puberty, and infertility.
Gene Anomalies
Just as genetic disorders can originate from
extra or missing chromosomes, so too can
they result from extra, missing, or abnormal
genes. One intriguing instance is Williams
syndrome. This rare genetic disorder in-
volves a variety of cognitive impairments,
most noticeably in spatial and visual skills,
but relatively less impairment in language
ability (e.g., Musolino & Landau, 2012;
Skwerer & Tager-Flusberg, 2011). Individu-
als with Williams syndrome are also typically
characterized by outgoing personalities and
friendliness paired with anxiety and pho-
bias. This condition has been traced to the
deletion of a small section of approximately
25 genes on chromosome 7. Some individ-
uals, however, have a smaller deletion; in
BOX 3.1: applications
GENETIC TRANSMISSION OF DISORDERS

N A T u R E A N D N u R T u R E n 95
these cases, the degree of impairment is
decreased, suggesting a clear relationship
between the number of genes deleted and
the resulting phenotype (Karmiloff-Smith et
al., 2012). Interestingly, some individuals
show a duplication of the same section of
genes that is deleted in Williams syndrome.
In this disorder, known as 7q11.23 duplica-
tion syndrome, the pattern of abilities and
disabilities is flipped, with individuals ex-
hibiting relatively weak speech and language
abilities paired with relatively strong visuo-
spatial skills (Mervis & Velleman, 2011;
Osborne & Mervis, 2007).
Regulator Gene Defects
Many disorders are thought to originate
from defects in regulator genes, which, as
discussed on page 91, control the expres-
sion of other genes. For example, a defect
in the regulator gene that initiates the de-
velopment of a male can interrupt the nor-
mal chain of events, occasionally resulting
in a newborn who has female genitalia but
is genetically male. Such cases often come
to light when a young woman fails to begin
menstruating or when a fertility clinic dis-
covers that the reason a couple has failed
to conceive is that the person trying to get
pregnant is genetically male.
Unidentified Genetic Basis
In addition to the known gene-disorder links,
there are many syndromes whose genetic or-
igins are clear from their inheritance pat-
terns but whose specific genetic cause has
yet to be identified. For example, dyslexia
is a highly heritable reading disability that
probably stems from a variety of gene-based
conditions. Another example is Tourette syn-
drome. Individuals with this disorder gener-
ally display a variety of tics, ranging from
involuntary twitching and jerking to com-
pulsively blurting out obscenities. Research
suggests that Tourette syndrome probably
involves a complex pattern of inheritance,
making precise determination of the cause
very difficult (O’Rourke et al., 2009).
The same is true for autism spectrum dis-
order (ASD), which includes both autism
and Asperger syndrome and involves a wide
range of deficits in social skills and commu-
nication. In 2008, in various U.S. districts
monitored by the Centers for Disease Con-
trol, it was estimated that the ASD preva-
lence rate among 8-year-olds was 1 in 88
children (age 8 is thought to be the age of
peak prevalence), with boys being 5 times
more likely than girls to be identified as hav-
ing the disorder (Baio, 2012). The diagno-
sis of ASD is based on major impairments
in social interaction and communication
skills and a limited set of interests or re-
petitive behaviors. Individuals with Asperger
syndrome tend to have a milder array of
symptoms and usually do not experience dif-
ficulties in language development.
ASD includes individuals with not only a
range of disabilities but also, in some cases,
remarkable talents in a narrowly focused
area, such as mathematics or drawing. ASD
is known to be highly heritable: twin studies
have revealed that identical twins (who share
100% of their genes) are more than twice
as likely as fraternal twins (who share 50%
of their genes) to share an autism diagnosis
(Ronald & Hoekstra, 2011). The difficulty
in identifying the specific genetic basis for
autism spectrum disorder is highlighted by
the fact that, at present, there are more than
100 candidate genes associated with ASD
(Geschwind, 2011; L. M. Xu et al., 2012).
The number of children diagnosed with
ASD has increased dramatically in recent
years. Indeed, in the districts tracked by the
Centers for Disease Control, the ASD prev-
alence estimates for 8-year-olds in 2008
represented a 78% increase over those for
2002 (Baio, 2012). Part of the increase is
believed to be due to greater public aware-
ness of the syndrome, leading to a higher
level of detection by parents, teachers, and
doctors. In addition, current diagnostic cri-
teria are broader than those of the past. It is
thus unclear to what degree the increased
level of diagnoses accurately reflects a
change in the actual incidence of ASD (e.g.,
Gernsbacher, Dawson, & Goldsmith, 2005).
One factor that was highly publicized as
a possible cause of the so-called autism ep-
idemic—the MMR vaccine that is routinely
given to young children to prevent measles,
mumps, and rubella—has been definitively
ruled out (A. W. McMahon et al., 2008; Price
et al., 2010). Indeed, the original study re-
porting a link between the MMR vaccine and
ASD (Wakefield et al., 1998) has been shown
to be fraudulent and has been retracted
(Godlee, Smith, & Marcovitch, 2011). Un-
fortunately, however, some parents continue
to deny their children this important vaccine,
needlessly putting them at risk for the ill-
nesses that the vaccine prevents.
One of the most common
identifiable causes of intel-
lectual disability is Down
syndrome, which occurs in
about 1 of every 1000 births
in the United States. The risk
increases dramatically with
the age of the parents, espe-
cially the mother; by the age
of 45, a woman has 1 chance
in 32 of having a baby with
Down syndrome. The degree
of disability varies greatly and
depends in part on the kind
of care and early intervention
children receive.
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96 n chapTer 3 BIOLOGY AND BEHAVIOR
parents cannot metabolize phenylalanine, an amino acid present in many foods
(especially red meats) and in artificial sweeteners. If they eat a normal diet, phe-
nylalanine accumulates in the bloodstream, causing impaired brain development
that results in severe intellectual impairment. However, if infants
with the PKU gene are identified shortly after birth and placed on
a stringent diet free of phenylalanine, intellectual impairment can
be avoided, as long as the diet is carefully maintained. Thus, a given
genotype results in quite different phenotypes—cognitive disabil-
ity or relatively normal intelligence—depending on environmen-
tal circumstances. Because early detection of this genetic disorder
has such a positive effect on children’s developmental outcomes,
all newborn infants in the United States are routinely screened for
PKU, as well as for a number of other severe and easily detected ge-
netic disorders.
A second example of a genotype–environment interaction comes
from an important study showing that the effects of abusive parent-
ing vary in severity as a function of the child’s genotype (Caspi et
al., 2002). The researchers wanted to determine why some children
who experience severe maltreatment become violent and antisocial
as adults, whereas others who are exposed to the same abuse do
not. The results, shown in Figure 3.5, revealed the importance of a
High elevation
Medium elevation
Low elevation
50
H
ei
gh
t
(c
m
)
0
50
H
ei
gh
t
(c
m
)
0
50
H
ei
gh
t
(c
m
)
0
FIGURE 3.4 The norm of reaction con-
cept This classic figure illustrates how a
given genotype can develop differently in
different environments. Three cuttings were
made from each of seven individual plants;
thus, the cuttings in each set of three had
identical genes. The three cuttings from each
plant were then planted at three different ele-
vations, ranging from sea level to high moun-
tains. The question of interest was whether
the orderly differences in height that were
observed at the low elevation would persist at
the two higher elevations. as you can see, the
order of the heights of the plants is neither
orderly nor consistent across the different
environments. For example, the first plant
on the left that is the tallest one at sea level
and at high elevation is one of the shortest at
medium elevation. The fourth plant is tallest
at the medium elevation and shortest at the
highest. Notice that not a single plant is
always either the tallest or the shortest across
the three elevations. “The phenotype is the
unique consequence of a particular geno-
type developing in a particular environment”
(Lewontin, 1982, pp. 22–23).
Severe
Childhood maltreatment
ProbableNone
–0.25
–0.5
0
0.25
0.5
0.75
1
C
om
p
os
it
e
in
d
ex
o
f
an
ti
so
ci
al
b
eh
av
io
r
(z
s
co
re
s)
Low MAOA
activity, n = 163
High MAOA
activity, n = 279
FIGURE 3.5 Genotype and environ-
ment This graph shows the level of anti-
social behavior observed in young men as
a function of the degree to which they had
been maltreated in childhood. as this figure
shows, those young men who had experi-
enced severe maltreatment were in general
more likely to engage in antisocial behavior
than were those who had experienced none.
however, the effect was much stronger for
those individuals who had a relatively inac-
tive MaOa gene. (adapted from caspi et al.,
2002, p. 852)

N A T u R E A N D N u R T u R E n 97
combination of environmental and genetic factors leading to antisocial outcomes—
suffering abusive treatment as a child and possessing a particular variant of MAOA,
an X-linked gene known to inhibit brain chemicals associated with aggression.
Young men who had a relatively inactive version of the MAOA gene, and who had
experienced severe maltreatment, grew up to be more antisocial than other men.
More concretely, 85% of the maltreated group with the relatively inactive gene
developed some form of antisocial behavior, and they were almost 10 times more
likely to be convicted of a violent crime. The important point here is that neither
factor by itself (possessing the inactive MAOA gene or being abused) predisposed
boys to become highly aggressive; the higher incidence of antisocial behavior was
observed only for the group with both factors. As the authors of that study note,
knowledge about specific genetic risk factors that make people more susceptible
to particular environmental effects could strengthen multiple-risk models, such as
those discussed in the previous two chapters.
parental contributions to the child’s environment Obviously, a highly salient
and important part of a child’s environment is the parents’ relationship with the
child—the manner in which they interact with him or her, the general
home environment they provide, the experiences they arrange for the
child, the encouragement they offer for particular behaviors, attitudes,
and activities, and so on. Less obvious is the idea that the environment
that parents provide for their children is due in part to the parents’ own
genetic makeup. Parents’ behavior toward their children (e.g., how warm
or reserved they are, how patient or short-fused) is genetically influ-
enced, as are the kinds of preferences, activities, and resources to which
they expose their children (Plomin & Bergeman, 1991). For example,
the child of a highly musical parent is likely to hear more music while
growing up than are children whose parents are less musically inclined.
Parents who are skilled readers and enjoy and value reading are likely
to read often for pleasure and information and are likely to have lots of
books around the house. They are also more likely to read frequently to
their children and to take them to the library. In contrast, parents for
whom reading is challenging and not a source of pleasure are less likely
to provide a highly literate environment for their children (Scarr, 1992).
4. Child’s Phenotype–Child’s Environment
Relation 4 in our model restates the active child theme—the child as a source of his or
her own development. As noted in Chapter 1, children are not just the passive recipi-
ents of a preexisting environment. Rather, they are active creators of the environment
in which they live in two important ways. First, by virtue of their nature and behav-
ior, they actively evoke certain kinds of responses from others (Scarr, 1992; Scarr &
McCartney, 1983). Babies who enjoy being cuddled are more likely to receive cud-
dling than are squirmy babies. Impulsive children hear “No,” “Don’t,” “Stop,” and “Be
careful” more often than inhibited children do. Indeed, the degree to which parent–
child relationships are mutually responsive is largely a function of the child’s geneti-
cally influenced behavioral characteristics (Deater-Deckard & O’Connor, 2000).
The second way in which children create their own environment is by actively
selecting surroundings and experiences that match their interests, talents, and per-
sonality characteristics (Scarr, 1992). As soon as infants become capable of self-
locomotion, for example, they start selecting certain objects in the environment for
This parent enjoys reading novels for plea-
sure and reads extensively for her work.
She is providing a rich literary environment
for her young child. The child may become
an avid reader both because his mother’s
genetic makeup contributed to his enjoy-
ment of reading and because of the physical
environment (lots of books) and the social
environment (encouragement of an interest
in books) that the mother has provided.
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98 n chapTer 3 BIOLOGY AND BEHAVIOR
exploration. Some very young children (especially boys) develop extremely intense
interests in particular kinds of objects or activities that do not stem from parental
encouragement (DeLoache, Simcock, & Macari, 2007). For example, many little
boys become obsessed with vehicles and construction equipment. Other young
children develop idiosyncratic and even quite peculiar interests (e.g., blenders,
roadkill). For many parents, the origin of these preschool passions is totally ob-
scure, and occasionally worrisome, because they do not realize how common these
intense interests actually are.
Beginning in the preschool years, children’s friendship opportunities increasingly
depend on their own characteristics, as they choose playmates and pals with whom
they feel compatible—the “birds of a feather flock together” phenomenon. And, as
noted in Chapter 1, with age, children play an ever more active role in selecting their
own environment. As they gain more autonomy, they increasingly select aspects of
the environment that fit their temperament and abilities. Returning to the reading
example, children who enjoy reading will read more books than will children who
find reading tedious. The more they read, the more skillful readers they become,
leading them to choose increasingly more challenging books, which, in turn, leads
them to acquire advanced vocabulary, improve their language comprehension, and
enhance their general knowledge base, resulting in greater success in school.
5. Child’s Environment–Child’s Genotype
The fifth relationship in our model is perhaps the most surprising. Until fairly re-
cently, geneticists thought of the genotype as being “fixed” at birth. But as discussed
in Chapter 1 (page 11), the new field of epigenetics has turned this conventional
wisdom on its head. That is, it is now known that although the structure of DNA
remains “fixed” (mutations aside), certain epigenetic mechanisms, mediated by the
environment, can alter the functioning of genes and create stable changes in their
expression—and some of these changes can be passed on to the next generation.
Epigenetic factors can help explain why identical twins do not have identical
pathways through life: different environments can alter gene expression in subtle
ways across developmental time. These stable changes in gene expression that are
mediated by the environment involve processes of methylation, which silence gene
expression. Differences in experience over the course of development are reflected
in differences in methylation levels. Consider identical twin pairs at the age of 3
and at the age of 50, for example. Three-year-old co-twins have had highly over-
lapping life experiences, whereas many 50-year-old co-twins are likely to have had
a far more divergent range of experiences. In a study that measured differences
in DNA methylation levels in 3- and 50-year-old identical co-twins, researchers
found that, whereas there were virtually no differences in the 3-year-olds’ levels,
roughly one-third of the 50-year-olds showed “remarkable” differences—and the
greater the differences in the twins’ lifestyle and experiences, the greater the differ-
ences in their methylation levels (Fraga et al., 2005).
How might the environment exert its effects through epigenetic mechanisms?
To date, the bulk of the behavioral research on this topic has focused on nonhuman
animal models, with clear evidence that low-quality maternal care has epigenetic
effects, permanently changing the animal’s pattern of gene expression (for a recent
review, see van IJzendoorn, Bakermans–Kranenburg, & Ebstein, 2011). In particu-
lar, poor maternal care affects the methylation of genes involved in glucocorticoid
receptors, which influence how the animal copes with stress (e.g., T.-Y. Zhang &
Meaney, 2010). As you saw in Chapter 1, there is emerging evidence suggesting

N A T u R E A N D N u R T u R E n 99
similar effects of early stress on methylation in humans (e.g., Essex et al., 2013).
The myriad risk factors associated with growing up in poverty appear to act on de-
veloping children via epigenetic processes as well; adults who grew up in impover-
ished households exhibit different patterns of gene expression decades later than
do adults who grew up in high-SES homes, regardless of their SES as adults (e.g.,
G. E. Miller et al., 2009).
Our discussion of the five kinds of gene–environment interactions has empha-
sized the myriad challenges in understanding how genes function in the devel-
opment of individuals. Nevertheless, the conceptualization we have presented is
greatly simplified. This is particularly true for the fifth relationship—epigenetics—
which, when considered in full, suggests that the line between genes and environ-
ment is blurry at best. The complexity of gene–environment relationships raises
both challenges and opportunities for developmental scientists. One challenge is
that the genome can no longer comfortably be considered immutable irrespective
of the widely varying environments in which children develop. One opportunity is
that as this field continues to develop, it may become possible to determine which
aspects of the environment are most likely to have a lasting impact on children’s
eventual health and well-being.
Behavior Genetics
The rapidly expanding field known as behavior genetics is concerned with how
variation in behavior and development results from the interaction of genetic and en-
vironmental factors. Behavior geneticists ask the same sort of question Galton asked
about eminence: “Why are people different from one another?” Why, in any group
of human beings, do we vary in terms of how smart, sociable, depressed, aggressive,
and religious we are? The answer given by behavior geneticists is that all behavioral
traits are heritable; that is, they are all influenced to some degree by hereditary fac-
tors (Bouchard, 2004; Turkheimer, 2000). As noted, the kind of traits that have been
of particular interest to behavior geneticists—intelligence, sociability, mood, aggres-
sion, and the like—are polygenic, that is, affected by the combination of many genes.
They are also multifactorial, that is, affected by a host of environmental factors as
well as genetic ones. Thus, the potential sources of variation are vast.
To fully answer Galton’s question, behavior geneticists try to tease apart genetic
and environmental contributions to the differences observed among a population
of people or other animals. Two premises underlie this endeavor:
1. To the extent that genetic factors are important for a given trait or behavior,
individuals who are genotypically similar should be phenotypically similar. In
other words, behavior patterns should “run in families”: children should be
more similar to their parents and siblings than to second- or third-degree rel-
atives or unrelated individuals.
2. To the extent that shared environmental factors are important, individuals who
were reared together should be more similar than people who were reared apart.
Behavior Genetic Research Designs
As it was for Galton, the mainstay of modern behavior-genetics research is the
family study. In order to examine genetic and environmental contributions to a
given trait or characteristic, behavior geneticists first measure that trait in people
who vary in terms of genetic relatedness—parents and their children, identical and
behavior genetics n the science con-
cerned with how variation in behavior and
development results from the combina-
tion of genetic and environmental factors
heritable n refers to any characteristics
or traits that are influenced by heredity
multifactorial n refers to traits that are
affected by a host of environmental fac-
tors as well as genetic ones

100 n chapTer 3 BIOLOGY AND BEHAVIOR
fraternal twins, nontwin siblings, and so on. Next, they assess
how highly correlated the measures of the trait are among in-
dividuals who vary in the degree to which they are genetically
related. (As you may recall from Chapter 1, the strength and
direction of a correlation express the extent to which two vari-
ables are related; the higher the correlation, the more precisely
scores on one variable can be predicted from scores on the
other.) Finally, behavior geneticists compare the resulting cor-
relations to see if they are (1) higher for more closely related
individuals than for less closely related people, and (2) higher
for individuals who share the same environment than for in-
dividuals who do not.
There are several specialized family-study designs that are
particularly helpful in assessing genetic and environmental
influences. One is the twin-study design, which compares the
correlations for identical (monozygotic, or MZ) twins with
those for same-sex fraternal (dizygotic, or DZ) twins. As you will recall, identical
twins have 100% of their genes in common (though the expression of these genes
are affected by epigenetic factors over the course of development, as discussed in
the previous section), whereas fraternal twins are only 50% genetically similar (just
like nontwin siblings). For twins who grow up together, the degree of similarity of
the environment is generally assumed to be equal. Both types of twins shared the
same womb, were born at the same time, have lived in the same family and com-
munity, and are always the same age when tested. Thus, with different levels of
genetic similarity and essentially equal environmental similarity, the difference be-
tween the correlations for the two types of twins is treated as an index of the im-
portance of genetic factors. If the correlation between identical twins on a given
trait or behavior is substantially higher than that between fraternal
twins, it is assumed that genetic factors are substantially responsible
for the difference.
Another family-study design used for assessing genetic and envi-
ronmental influences is the adoption study. In this approach, research-
ers examine whether adopted children’s scores on a given measure
are correlated more highly with those of their biological parents and
siblings or with those of their adoptive parents and siblings. Genetic
influences are inferred to the extent that children resemble their bio-
logical relatives more than they do their adoptive ones.
The ideal behavior-genetics design—the adoptive twin study—
compares identical twins who grew up together versus identical twins
who were separated shortly after birth and raised apart. If the correla-
tions for twins reared apart are similar to those for twins reared together,
it suggests that environmental factors have little effect. Conversely, to
the extent that the correlations between identical twins who grew up
in different environments are lower than those for identical twins who
grew up together, environmental influence is inferred. Box 3.2 describes
some of the remarkable findings that have emerged from studies of
twins reared apart, as well as some of the problems with such research.
Family studies of intelligence The most common focus of
behavior-genetics family studies has been intelligence. Table 3.1 sum-
marizes the results of more than 100 family studies of IQ through
©
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“The title of my science project is ‘My LIttle Brother: Nature or Nurture.’”
TABLE 3.1
Summary of Family Studies of Intelligence
Average Familial IQ Correlations (R)
Relationship Average R Reared-together
biological relatives
Number of Pairs
MZ twins 0.86 4672
DZ twins 0.60 5533
Siblings 0.47 26,473
Parent–offspring 0.42 8433
Half siblings 0.35 200
Cousins 0.15 1176
Reared-apart
biological relatives
MZ twins 0.72 65
Siblings 0.24 203
Parent–offspring 0.24 720
Reared-together
nonbiological relatives
Siblings 0.32 714
Parent–offspring 0.24 720
Note: MZ 5 monozygotic; DZ 5 dizygotic.
Source: McGue et al. (1993)

N A T u R E A N D N u R T u R E n 101
adolescence. The pattern of results reveals both genetic and environmental in-
fluences. Genetic influence is shown by generally higher correlations for higher
degrees of genetic similarity. Most notable is the finding that identical (MZ) twins
resemble one another in IQ more than do same-sex fraternal (DZ) twins. At the
same time, environmental influences are reflected in the fact that iden tical twins are
not identical in terms of IQ. Further evidence for an environmental role is that MZ
twins who are reared together are more similar than those reared apart.
Oskar Stohr and Jack Yufa are identical
twins who were separated shortly after their
birth in Trinidad. Oskar was raised by his
grandmother in Germany as a Catholic and
a Nazi. Jack was raised by his father, in the
Caribbean, as a Jew. Despite their very dif-
ferent backgrounds, when the brothers first
met as middle-aged men recruited for a re-
search study in Minneapolis, they discov-
ered a remarkable number of similarities
between them:
They like spicy foods and sweet li-
queurs, are absent-minded, have a
habit of falling asleep in front of the
television, think it’s funny to sneeze
in a crowd of strangers, flush the toi-
let before using it, store rubber bands
on their wrists, read magazines back
to front, dip buttered toast in their
coffee. Oskar is domineering toward
women and yells at his wife, which
Jack did before he was separated.
(Holden, 1980, p. 1324)
Jack and Oskar are participants in the
Minnesota Study of Twins Reared Apart, an
extensive research project on identical twins
separated early in life (Bouchard et al.,
1990). More than 100 pairs of such twins
have been located, recruited for the study,
and brought to Minneapolis to undergo an
extensive battery of physiological and psy-
chological tests. Many twin siblings were
meeting for the first time since infancy. (The
reunited twins in the photo at right showed
almost as many striking similarities as did
Jack and Oskar, including their having held
several very similar jobs and being volunteer
firemen.) The motivation for this large-scale
study is to examine genetic and environ-
mental contributions to development and
behavior by comparing individuals who are
genetically identical but who grew up in dif-
ferent environments.
The Minnesota team of investigators has
been struck by the extent of the similari-
ties they have found in the separated twins;
they have identified genetic contributions
to “almost every behavioral trait so far in-
vestigated from reaction time to religiosity”
(Bouchard et al., 1990).
As striking as the similarities between
separated twins may be, there are several
problems with automatically
assuming that these similar-
ities are attributable to ge-
netic factors. One issue is
that it would be a great over-
simplification to suggest that
all of the similar traits shared
by separated twins are ge-
netic. For example, it would
be a stretch to argue that the
men in the photograph share
a set of genes that predeter-
mined that they both would
become firemen. As previ-
ously noted, genes code for
proteins, not for anything as complex as
an occupation (or choice of facial hair). An
additional issue is the practice of selective
placement: adoption agencies generally try
to place children with families of the same
general background and race, so the envi-
ronments of the separated siblings are often
similar in many ways. It is extremely rare
for separated twins to be raised like Jack
and Oskar, with different languages, reli-
gions, and cultures. In fact, the majority of
the twins in most behavior-genetics studies
are from predominantly White, middle-class
families in Western countries. As behav-
ior geneticists Levine and Suzuki (1993)
commented:
Take one of those kids and put him in
a really different environment, like
in a family of bushmen in Africa, or in
a farming village in mainland China,
and then come back twenty years
later and see if you find two firemen
who dress the same!
(p. 241)
BOX 3.2: individual differences
IDENTICAL TWINS REARED APART
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Identical twins Gerald Levey and Mark
Newman were separated at birth and reared
separately in middle-class Jewish homes in the
New York area. When reunited at the age of
31, they discovered, among many other simi-
larities, that they were both volunteer firemen
with droopy moustaches; long sideburns; and a
penchant for hunting, fishing, and John Wayne
movies. They even drank the same brand of
beer, from a can, which they held with their
pinkie tucked under the bottom and crushed
when they had emptied it.

102 n chapTer 3 BIOLOGY AND BEHAVIOR
Does the relative influence that genes and environment have on intelligence
change over the course of development? One might expect that as children get
older and have ever more (and more varied) experiences in the world, genetic in-
fluences on IQ would decrease. Surprisingly, recent studies have revealed exactly
the opposite pattern: as twins get older, the degree of variance in IQ accounted for
by their genetic similarity increases. In a study of 11,000 MZ and DZ twin pairs
across four countries, researchers found that the correlations in IQ between co-
twins increased with age for MZ twins and decreased with age for DZ twins. These
divergent patterns were observed first from childhood to adolescence, and again
from adolescence to young adulthood (Haworth et al., 2009). The same pattern of
results was revealed in a large longitudinal study that compared MZ and DZ twin
pairs in early childhood (2- to 4-year-olds) and middle childhood (7- to 10-year-
olds): for the younger children, shared environment accounted for more variance
than did shared genes, with the opposite pattern observed for the older children
(O. S. P. Davis, Haworth, & Plomin, 2009).
This surprising pattern of results—namely, that genetic influences increase with
age—is consistent with the idea that people actively construct their own envi-
ronment: the phenotype–environment correlation (Relation 3) discussed earlier
(McGue et al., 1993; Scarr & McCartney, 1983). As children get older, they in-
creasingly control their own experiences, and their parents have less influence over
their activities. The effects of education may be particularly relevant to this pattern
of results, given that educational experiences and achievements influence children’s
performance on measurements of intelligence. Younger children have little or no
choice about their educational setting and opportunities, whereas older children,
teens, and young adults have increasingly greater choices with regard to their edu-
cational experiences (choosing more or less challenging courses of study, more or
less academically oriented peer groups, and so on). It may be that identical twins’
IQs become more similar into adulthood because their common genetic predisposi-
tions lead them to select similar intellectual stimulation, whereas the IQs of frater-
nal twins become increasingly dissimilar because they choose divergent experiences
for themselves (Scarr & McCartney, 1983).
Heritability
In their approach to the nature–nurture question, many behavior geneticists at-
tempt to quantify the degree to which genes contribute to various traits. To es-
timate how much of the variability in measures of a given trait is attributable to
genetic and environmental factors, they derive heritability estimates from correla-
tions of the type shown in Table 3.1. Heritability is a statistical estimate of how
much of the measured variance on a trait among individuals in a given population
is attributable to genetic differences among those individuals.
A crucial point to understand about heritability estimates is that they tell us
nothing about the relative contributions of genetic and environmental factors to
the development of an individual. Instead, they estimate how much of the varia-
tion among a given population of people is due to differences in their genes. The
heritability estimate for intelligence, for example, is generally considered to be ap-
proximately 50% (Bouchard, 2004; Plomin, 1990). This means that, for the popula-
tion studied, roughly 50% of the variation in IQ scores is due to genetic differences
among the members of the population. (It does not mean that 50% of your IQ score
is due to your genetic makeup and 50% is due to your experience.) Note that this
heritability estimate indicates that the environmental contribution to the variation
in IQ is also approximately 50%.
heritability n a statistical estimate of
the proportion of the measured variance
on a trait among individuals in a given
population that is attributable to genetic
differences among those individuals

N A T u R E A N D N u R T u R E n 103
Behavior-genetic analyses have been applied to many diverse aspects of human
behavior, several of which you will encounter in other chapters of this book. To cite
just a few examples, substantial heritability has been reported for infant activity
level (Saudino & Eaton, 1991), temperament (Goldsmith, Buss, & Lemery, 1997),
reading disability (DeFries & Gillis, 1993), and antisocial behavior (Gottesman
& Goldsmith, 1994). Substantial heritability has even been reported for divorce
(McGue & Lykken, 1992), TV viewing (Plomin et al., 1990), and other factors that
previously seemed more likely to be influenced by the environment than by genetics
(e.g., Jaffee & Price, 2007).
The implausibility of “divorcer” or “couch potato” genes brings us back to a
point we made earlier: despite the common use of the phrase, there are no genes
“for” particular behavior patterns. As have we stressed, genes do nothing more than
code for proteins, so they affect behavior only insofar as those proteins affect the
sensory, neural, and other physiological processes involved in behavior. Thus, the
heritability estimate for divorce may be related to a genetic predisposition to, say,
seek out novelty, and the estimate for TV viewing may be related to a genetically
based low activity level or short attention span.
Heritability estimates have been criticized, both from within psychology
(e.g., G. Gottlieb, Wahlsten, & Lickliter, 1998; Lerner, 1995) and from outside
it (e.g., J. S. Levine & Suzuki, 1993; Lewontin, 1982). Part of the criticism stems
from ways that the term “heritability” is often misinterpreted or misused by the
public. One very common misuse involves the application of the concept of heri-
tability to individuals, despite the fact that, as we have emphasized, heritability ap-
plies only to populations.
In addition, a heritability estimate applies only to a particular population living in
a particular environment. Consider the case of height. Research conducted almost
exclusively with North Americans and Europeans—most of them White and ad-
equately nourished—puts the heritability of height at around 90%. But what if
some segment of this population had experienced a severe famine during child-
hood, while the rest remained well fed? Would the heritability estimate for height
still be 90%? No—because the variability due to environmental factors (poor nutri-
tion) would increase dramatically and, therefore, the variability that could be attrib-
uted to genetic factors would decrease to the same degree. The principle of variable
heritability also appeared in the discussion of IQ correlations earlier in this chapter,
with the heritability estimates derived from them differing for the same individuals
at different points in development (O. S. P. Davis et al., 2009).
Furthermore, it is known that heritability estimates can differ markedly for
groups of people who grow up in very different economic circumstances. In the
United States, for instance, heritability estimates differ considerably as a function
of socioeconomic status (SES), as shown by a large twin study that included fami-
lies across the SES spectrum (Turkheimer et al., 2003). In this study, almost 60% of
the variance in IQ among a sample of 7-year-olds living in poverty was accounted
for by shared environment, with almost none of it attributable to genetic similar-
ity. Affluent families follow the opposite pattern, with genetic factors contribut-
ing more than environmental ones. In a related study focused on the test scores of
adolescent twins, the same pattern was observed: environmental factors trumped
genetic factors for poorer teens, while genetic factors trumped environmental fac-
tors for wealthier teens (Harden, Turkheimer, & Loehlin, 2007). Although it is not
fully clear what causes these differing levels of heritability, both studies suggest that
qualitatively different developmental forces may be operating in poor versus afflu-
ent environments.

104 n chapTer 3 BIOLOGY AND BEHAVIOR
A related, frequently misunderstood point is that high heritability does not imply
immutability. The fact that a trait is highly heritable does not mean that there is lit-
tle point in trying to improve the course of development related to that trait. Thus,
for example, the fact that the heritability estimate for IQ is relatively high does not
mean that the intellectual performance of young children living in poverty cannot
be improved by appropriate intervention efforts (see Chapter 8, pages 317–320).
Finally, because they are relevant only within a given population, heritability es-
timates tell us nothing about differences between groups. The heritability score for
IQ , for example, provides little insight into the meaning of differences in the IQ
scores of different groups of Americans. European Americans, on average, score
15 points higher on IQ tests than do African Americans. Some people mistakenly
assume that because IQ is estimated to be 50% heritable, the difference between
these two groups’ IQ scores is genetically based. This assumption is unwarranted,
given the large overall disparities between the two groups in family income and
education, quality of neighborhood schools, health care, and myriad other factors.
Environmental Effects
Every examination of genetic contributions to behavior and development is also,
necessarily, a study of environmental influences: estimating heritability automati-
cally estimates the proportion of variance not attributable to genes. Because herita-
bility estimates rarely exceed 50%, a large contribution from environmental factors
is usually indicated.
Behavior geneticists try to assess the extent to which aspects of an environment
shared by biologically related people make them more alike and to what extent non-
shared experiences make them different. The most obvious source of shared envi-
ronment is growing up in the same family. Shared-environment effects can also be
inferred when twins or other relatives are more similar on some trait than would be
expected on the basis of their genetic relatedness. For example, substantial shared-
environmental influence has been inferred for positive emotion in toddlers and
young children because fraternal and identical twins who were reared together were
equally similar in the degree to which they showed pleasure (Goldsmith et al., 1997).
The similarity between these identical twins
may be enhanced by environmental factors.
Sharing similar abilities, they may enjoy
similar activities and be exposed to similar
environmental influences. Being of similar
intelligence, they are likely to have relatively
similar experiences in school. Later, they
may enjoy similar success in dating and end
up with spouses of similar social class. TO
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N A T u R E A N D N u R T u R E n 105
Shared-environment effects are also being discovered for disorders that have a clear
genetic component. For instance, as discussed in Box 3.1, twin studies of autism
spectrum disorder (ASD) have consistently provided evidence for genetic effects
(with heritability of the disorder being greater for MZ twins than for DZ twins).
However, in a recent large-scale study of twin pairs in which at least one co-twin had
an ASD diagnosis, researchers found a substantial shared-environment effect on the
likelihood that the second twin also had an ASD diagnosis (Hallmayer et al., 2011).
Surprisingly, behavior geneticists have reported little evidence of shared-
environment effects for some other aspects of development. For example, with
respect to personality, the correlations for adoptive siblings are often near zero
(D. C. Rowe, 1994). The same is true for some types of psychopathology, includ-
ing schizophrenia (Gottesman, 1991). As noted in Chapter 1, being adopted into
a family with a schizophrenic sibling does not increase the risk that a child will be-
come schizophrenic. In addition, the risk of schizophrenia is the same for the bio-
logical child of a schizophrenic parent regardless of whether the child is raised by
that parent or is adopted away at birth (Kety et al., 1994).
Behavior geneticists’ investigations of the effects of nonshared environments
arise from the recognition that even children who grow up in the same family do
not have all their experiences in common—either inside or outside the family.
Within the family, birth order may result in quite different experiences for siblings.
The oldest child in a large family, for example, may have been reared by young, en-
ergetic, but inexperienced, parents, whereas that child’s much younger sibling will
be parented by older and more sedentary, but more knowledgeable, individuals who
are likely to have more resources available than they did as first-time parents. In
addition, as discussed in Chapter 1, siblings may experience their parents’ behavior
toward them differently (the “Mom always loved you best” syndrome). They may
also be affected quite differently by an event they experience in common, such as
the divorce of their parents (Hetherington & Clingempeel, 1992). Finally, siblings
may be highly motivated to differentiate themselves from one another (Sulloway,
1996). The younger sibling of a star student may strive to be a star athlete instead,
and a child who observes a sibling disappearing into a self-destructive pattern of
drug and alcohol abuse may become determined to follow a different path. As these
examples illustrate, siblings themselves are an important part of the environment,
and each provides a different constellation of experiences for the others. This is an-
other factor that makes each child’s experience within the family different.
Outside the family, siblings can also have highly divergent experiences, partly
as a result of belonging to different peer groups. Highly active siblings who both
like physical challenges and thrills will have very different experiences if one takes
up rock climbing while the other hangs out with delinquents. Idiosyncratic life
events—suffering a serious accident, having an inspiring teacher, being bullied on
the playground—can contribute further to making siblings develop differently. The
primary effect of nonshared environmental factors is to increase the differences
among family members (Plomin & Daniels, 1987).
review:
The five relations shown in Figure 3.1 depict the complex interplay of genetic and environ-
mental forces in development. (1) The course of children’s development is influenced by the
genetic heritage they receive from their mother and father, with their sex determined solely
by their father’s chromosomal contribution. (2) The relation between children’s genotype and
phenotype depends in part on dominance patterns in the expression of some genes, but most

106 n chapTer 3 BIOLOGY AND BEHAVIOR
traits of primary interest to behavioral scientists are influenced by multiple genes (polygenic
inheritance). (3) As the concept of norm of reaction specifies, any given genotype will develop
differently in different environments. A particularly salient part of children’s environment is
their parents, including their parents’ own genetic makeup, which influences how parents be-
have toward their children. (4) Children’s own genetic makeup influences how they select and
shape their own environment and the experiences they have in it. (5) Conversely, children’s
experiences can change their genetic expression through epigenetic mechanisms.
The field of behavior genetics is concerned with how development results from the inter-
action of genetic and environmental factors. Using the family-study methodology, behavior
geneticists compare the correlations among individuals who vary in the degree of genetic re-
latedness and in similarity of their rearing environments. Heritability estimates indicate the
proportion of the variance among individuals in a given population on a given trait that is
attributable to genetic differences among them. Most behavioral traits that have been mea-
sured show substantial heritability; at the same time, heritability estimates reveal the close
partnership of heredity and environment in development and the fallacy of considering the
influences of nature and nurture as independent of one another.
Brain Development
As you will see, the collaboration between nature and nurture takes center stage in
the development of the brain and nervous system. Before discussing developmental
processes in the formation of the brain, however, we need to consider the basic com-
ponents of this “most complex structure in the known universe” (R. F. Thompson,
2000, p. 1).
Fundamental to all aspects of behavioral development is the development of the
central nervous system and especially the brain. The brain is the font of all thought,
memory, emotion, imagination, personality—in short, the behavior, capacities, and
characteristics that make us who we are.
Structures of the Brain
In our examination of the structures of the brain, we focus our discussion on two
that are central to behavior—the neuron and the cortex, as well as some of their
substructures.
Neurons
The business of the brain is information. The basic units of the brain’s remarkably
powerful informational system are its more than 100 billion neurons (Figure 3.6),
which constitute the gray matter of the brain. These cells are specialized for send-
ing and receiving messages between the brain and all parts of the body, as well as
within the brain itself. Sensory neurons transmit information from sensory receptors
that detect stimuli in the external environment or within the body itself; motor neu-
rons transmit information from the brain to muscles and glands; and interneurons
act as intermediaries between sensory and motor neurons.
Although they vary substantially in size, shape, and function, all neurons are
made up of three main components: (1) a cell body, which contains the basic bio-
logical material that keeps the neuron functioning; (2) dendrites, fibers that receive
input from other cells and conduct it toward the cell body in the form of electrical
impulses; and (3) an axon, a fiber (anywhere from a few micrometers to more than
a meter in length) that conducts electrical signals away from the cell body to con-
nections with other neurons.
neurons n cells that are specialized for
sending and receiving messages between
the brain and all parts of the body, as well
as within the brain itself
cell body n a component of the neuron
that contains the basic biological material
that keeps the neuron functioning
dendrites n neural fibers that receive
input from other cells and conduct it
toward the cell body in the form of elec-
trical impulses
axons n neural fibers that conduct elec-
trical signals away from the cell body to
connections with other neurons

B R A I N D E V E L O P M E N T n 107
Neurons communicate with one another at synapses, which are microscopic
junctions between the axon terminal of one neuron and the dendritic branches of
another. In this communication process, electrical and chemical messages cross
the synapses and cause the receiving neurons either to fire, sending a signal on
to other neurons, or to be inhibited from firing. The total number of synapses is
staggering—hundreds of trillions—with some neurons having as many as 15,000
synaptic connections with other neurons.
Glial Cells
Glial cells, the brain’s white matter, make up nearly half the human brain, out-
numbering neurons 10 to 1. They perform a variety of critical functions, includ-
ing the formation of a myelin sheath around axons, which insulates them and
increases the speed and efficiency of information transmission. The importance
of myelin is highlighted by the severe consequences that can arise from disorders
that affect it. For example, multiple sclerosis is a disease in which the immune
Myelin sheath
Nucleus
Cell body
Axon
Axon terminals
Synapse
Dendrites
Transmitting neuron
Receiving neuron
FIGURE 3.6 The neuron The cell body
manufactures proteins and enzymes, which
support cell functioning, as well as the
chemical substances called neurotransmit-
ters, which facilitate communication among
neurons. The axon is the long shaft that con-
ducts electrical impulses away from the cell
body. Many axons are covered with a myelin
sheath, which enhances the speed and effi-
ciency with which signals travel along the axon.
Branches at the end of the axon have termi-
nals that release neurotransmitters into the
synapses—the small spaces between the axon
terminals of one neuron and the dendrites or
cell body of another. The dendrites conduct
impulses toward the cell body. an axon can
have synapses with thousands of other neurons.
(adapted from Banich, 1997)
synapses n microscopic junctions
between the axon terminal of one neuron
and the dendritic branches or cell body
of another
glial cells n cells in the brain that
provide a variety of critical supportive
functions
myelin sheath n a fatty sheath that
forms around certain axons in the body
and increases the speed and efficiency of
information transmission

108 n chapTer 3 BIOLOGY AND BEHAVIOR
system attacks myelin, interfering with neuronal signaling and producing varying
degrees of physical and cognitive impairment. Several psychiatric disorders, includ-
ing schizophrenia and bipolar disorder, are also linked to defects in the gene that
regulates production of myelin (e.g., Hakak et al., 2001; Tkachev et al., 2003).
Glial cells play a further role in communication within the brain by influencing
the formation and strengthening of synapses and by communicating biochemically
among themselves in a network separate from the neural network, and allowing
them to efficiently regulate many aspects of brain activity (Fields, 2004).
The Cortex
The cerebral cortex, the surface of which is shown in Figure 3.7, is considered the
“most human part of the human brain” (McEwen & Schmeck, 1994). Over the
course of human evolution, the brain expanded greatly in size. Almost all of this
increase occurred in the cerebral cortex, which constitutes 80% of the brain, a much
greater proportion than in other species. The folds and fissures that are apparent in
Figure 3.7 form during development as the brain grows within the confined space
of the skull; these convolutions make it possible to pack more cortex into the lim-
ited space.
The cortex plays a primary role in a wide variety of mental functions, from seeing
and hearing to reading, writing, and doing arithmetic and to feeling compassion and
communicating with others. As Figure 3.7 shows, the major areas of the cortex—
the lobes—can be characterized in terms of the general behavioral categories with
which they are associated. The occipital lobe is primarily involved in processing vi-
sual information. The temporal lobe is associated with memory, visual recognition,
speech and language, and the processing of emotion and auditory information. The
parietal lobe is important for spatial processing. It is also involved in the integration
of information from different sensory modalities, and it plays a role in integrating
Frontal lobe
Primary olfactory cortex
(mostly hidden from view)
Primary auditory cortex
(mostly hidden from view)
Temporal lobe
Prefrontal cortex
Parietal lobe
Primary visual
cortex (mostly
hidden from view)
Occipital lobe
Primary motor cortex Primary somatosensory cortex
FIGURE 3.7 The human
cerebral cortex This view of the
left hemisphere of an adult brain
shows the four major cortical
regions—known as the lobes—
which are divided from one
another by deep fissures. each
of the primary sensory areas
receives information from a par-
ticular sensory system, and the
primary motor cortex controls the
body’s muscles. Information from
multiple sensory areas is pro-
cessed in association areas.
cerebral cortex n the “gray matter” of
the brain that plays a primary role in what
is thought to be particularly humanlike
functioning, from seeing and hearing to
writing to feeling emotion
lobes n major areas of the cortex associ-
ated with general categories of behavior
occipital lobe n the lobe of the cortex
that is primarily involved in processing
visual information
temporal lobe n the lobe of the cortex
that is associated with memory, visual
recognition, and the processing of emo-
tion and auditory information
parietal lobe n governs spatial pro-
cessing as well as integrating sensory
input with information stored in memory

B R A I N D E V E L O P M E N T n 109
sensory input with information stored in memory and with information about inter-
nal states. The frontal lobe, the brain’s “executive,” is involved in cognitive control,
including working memory, planning, decision making, and inhibitory control. In-
formation from multiple sensory systems is processed and integrated in the associa-
tion areas that lie in between the major sensory and motor areas.
Although it is convenient to think of different cortical areas as if they were func-
tionally specific, they are not. It has become increasingly clear that complex mental
functions are mediated by multiple areas of the brain, with an extraordinary degree
of interactivity both within and across brain regions. A given area may be critical
for some ability, but that does not mean that control of that ability is located in that
one area. (Box 3.3 examines some of the techniques that researchers use to learn
about brain functioning.)
cerebral lateralization The cortex is divided into two separate halves, or cerebral
hemispheres. For the most part, sensory input from one side of the body goes to
the opposite side of the brain, and the motor areas of the cortex control movements
of the opposite side of the body. Thus, if you pick up a hot pot with your right hand,
it is the left side of the brain that receives the sensory response, registers the pain,
and initiates the motor response to let go immediately.
The left and right hemispheres of the brain communicate with each other pri-
marily by way of the corpus callosum, a dense tract of nerve fibers that connect
them. The two hemispheres are specialized for different modes of processing, a
phenomenon referred to as cerebral lateralization. There are notable similarities
across species in hemispheric specialization. For example, most aspects of speech
and language are lateralized to the left hemisphere in humans, with a similar asym-
metry observed for communicative signals in nonhuman species from mice to pri-
mates (Corballis, 2009).
Developmental Processes
How does the incredibly complex structure of the human brain come into being?
You will not be surprised to hear that, once again, a partnership of nature and nur-
ture is involved. Some aspects of the construction of the brain are set in motion and
tightly controlled by the genes, relatively independent of experience. But, as you
will see, other aspects are profoundly influenced by experience.
Neurogenesis and Neuron Development
In the 3rd or 4th week of prenatal life, cells in the newly formed neural tube begin
dividing at an astonishing rate—at peak production, 250,000 new cells are born
every minute. Neurogenesis, the proliferation of neurons through cell division, is
virtually complete by around 18 weeks after conception (Rakic, 1995; Stiles, 2008).
Thus, most of the roughly 100 billion neurons you currently possess have been with
you since before you were born. Notably, however, we do continue to generate new
neurons throughout life. During bouts of learning, for example, neurogenesis oc-
curs in the hippocampus, a brain region important for memory processes (E. Gould
et al., 1999). Neurogenesis does not always occur, however: it can be inhibited by
stress (Mirescu & Gould, 2006). This pattern of results suggests that neurogenesis
later in life is not fixed and predetermined but is instead adaptive, increasing under
rewarding conditions and decreasing in threatening environments (e.g., Glasper,
Schoenfeld, & Gould, 2012).
frontal lobe n associated with orga-
nizing behavior; the one that is thought
responsible for the human ability to plan
ahead
association areas n parts of the brain
that lie between the major sensory and
motor areas and that process and inte-
grate input from those areas
cerebral hemispheres n the two
halves of the cortex; for the most part,
sensory input from one side of the body
goes to the opposite hemisphere of the
brain
corpus callosum n a dense tract of
nerve fibers that enable the two hemi-
spheres of the brain to communicate
cerebral lateralization n the special-
ization of the hemispheres of the brain for
different modes of processing
neurogenesis n the proliferation of neu-
rons through cell division

110 n chapTer 3 BIOLOGY AND BEHAVIOR
After their “birth,” neurons begin the second developmental process, which in-
volves migration to their ultimate destinations. Some neurons are pushed along
passively by the newer cells formed after them, whereas others actively propel
themselves toward their ultimate location.
Once neurons reach their destination, cell growth and differentiation occur.
Neurons first grow an axon and then a “bush” of dendrites (refer back to Figure
Developmental scientists employ a variety of
techniques to determine what areas of the
brain are associated with particular behav-
iors, thoughts, and feelings and how brain
functions change with age. The existence of
increasingly powerful techniques for investi-
gating brain function has sparked a revolu-
tion in the understanding of the brain and its
development. Here, we provide examples of
some of the techniques most often used to
map the mind and its workings in children.
Electrophysiological Recording
One of the techniques most often used by de-
velopmental researchers to study brain func-
tion is based on electroencephalographic
(EEG) recordings of electrical activity gener-
ated by neurons. EEG is completely noninva-
sive (the recordings are obtained through an
electrode cap that simply rests on the scalp,
and can contain hundreds of electrodes), so
this method can be used successfully even
with infants (see photo at right). EEG record-
ings provide detailed information about the
time course of neural events, and have pro-
vided valuable information about a variety of
brain-behavior relations.
An electrophysiological technique that is
very useful for studying the relation between
brain activity and specific kinds of stimula-
tion is the recording of event-related poten-
tials (ERPs), that is, changes in the brain’s
electrical activity that occur in response to
the presentation of a particular stimulus.
One contribution these measures have made
is that they reveal continuity over time. For
instance, studies of infants’ ERPs in re-
sponse to native-speech sounds have shown
that infants’ ability to discriminate among
these sounds predicts their language growth
over the next few years (Kuhl et al., 2008). A
related method, called magnetoencephalog-
raphy (MEG), detects magnetic fields gener-
ated by electrical currents in the brain. MEG
has the added benefit of being the only non-
invasive imaging method that can be used
to study the fetal brain. Although the use of
MEG for this purpose is in its early stages,
researchers have so far been able to detect
fetal neural responses to auditory stimuli and
flashes of light displayed on the mother’s ab-
domen, as well as habituation responses to
repeated stimuli (Sheridan et al., 2010).
Functional Magnetic Resonance Imaging
Functional magnetic resonance imaging
(fMRI) uses a powerful electromagnet to de-
tect fluctuations in cerebral blood flow in
different areas of the brain. Increased blood
flow indicates increased activity, so this tech-
nology allows researchers to determine which
areas of the brain are activated by different
tasks and stimuli. Because a person must be
able to tolerate the noise and close confine-
ment of an MRI machine and must also be
able to remain very still, most developmental
fMRI studies have been done with children
aged 6 years or older, often using practice
sessions in a mock scanner to help children
acclimate to the MRI environment. However,
recent studies have used fMRI methods to
investigate neural processes in sleeping in-
fants as young as 2 days old. One such study
demonstrated that the areas of the brain that
are activated by spoken language from later
infancy onward are also activated by speech
in neonates (Perani et al., 2011).
Other Techniques
Positron emission tomography (PET) mea-
sures brain activity by detecting the brain’s
metabolic processes and has provided im-
portant information about brain develop-
ment. However, because PET scans involve
injecting radioactive material into the brain,
this technique is used primarily for diagnos-
tic purposes.
One of the newest methods to be used
in developmental studies is near-infrared
spectroscopy (NIRS), an optical imaging
technique that measures neural activity by
detecting metabolic changes that lead to
differential absorption of infrared light in
brain tissue. The infrared light is transmit-
ted to the brain, and its absorption is de-
tected by means of an optical-fiber skullcap
or headband. Because NIRS is silent, non-
invasive, and does not require rigid stabiliza-
tion of the head, it is particularly promising
BOX 3.3: a closer look
MAPPING THE MIND
eeG This eeG cap holds electrodes snugly
against the baby’s scalp, enabling researchers
to record electrical activity generated from all
over the baby’s brain.
C
O
u
R
T
E
S
Y
C
H
A
R
LE
S
A
.
N
E
LS
O
N
event-related potentials (ERPs) n
changes in the brain’s electrical activity
that occur in response to the presentation
of a particular stimulus

B R A I N D E V E L O P M E N T n 111
3.6). Thereafter, they take on the specific structural and functional characteristics
of the different structures of the brain. Axons elongate as they grow toward specific
targets, which, depending on the neuron in question, might be anything from an-
other neuron in the brain to a bone in the big toe. The main change in dendrites is
“arborization”—an enormous increase in the size and complexity of the dendritic
“tree” that results from growth, branching, and the formation of spines on the
for research with infants and young chil-
dren. Thus far, a number of attempts to pin-
point infants’ brain activation in response
to particular stimuli have shown mixed re-
sults, in part because the technology is still
in its early stages (Aslin, 2012). One use
of NIRS that has already proved success-
ful is the monitoring of brain-oxygen levels
in premature newborns. Another particularly
interesting and successful application of
NIRS involved a study of deaf children who
had just received a cochlear implant, a sur-
gically implanted electronic hearing device
that we will discuss in Chapter 6. Because
of concerns about the effects of its mag-
netic field, fMRI cannot be used to study
brain processes in individuals with implants.
NIRS was thus used to determine whether
the auditory cortices of these children could
respond to auditory stimulation. The NIRS
showed that, rather remarkably, the auditory
cortex of deaf children responded to sound
within hours after the implant was activated,
even though the cortex had never before
been exposed to sound (Sevy et al., 2010).
fMrI images The figure shows fMrI images of the brains
of a 9-year-old (panel a) and a 24-year-old (panel B) in a
standard cognitive task that requires responding to some
stimuli but inhibiting responding to others. (The images to
the left show the “slices” of the brain averaged together in
the images on the right.) The results show that the location
of activation in the prefrontal cortex did not differ between
children and adults, but the overall extent of activation was
greater for the children (casey, 1999). RE
P
R
IN
T
E
D
W
IT
H
P
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M
IS
S
IO
N
F
R
O
M
B
.
J.
C
A
S
E
Y
(
1
9
9
9
)
spines n formations on the dendrites
of neurons that increase the dendrites’
capacity to form connections with other
neurons
Milliseconds
M
ic
ro
vo
lt
s
160012008004000
40
0
–40
Milliseconds
M
ic
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vo
lt
s
160012008004000
40
0
–40
erp responses This figure shows erp wave-
forms in response to novel (red line) and
familiar (yellow line) stimuli. The infants
who later recalled how to assemble a toy (left
panel) had clearly discriminated between the
familiar and novel items on an earlier recogni-
tion test. The infants who did not recall the
assembly sequence (right panel) had not dis-
criminated between the components on the
earlier test. (adapted from L. J. carver, Bauer,
& Nelson, 2000)

112 n chapTer 3 BIOLOGY AND BEHAVIOR
branches. Arborization enormously increases the dendrites’ capacity to form con-
nections with other neurons. In the cortex, the period of most intense growth and
differentiation comes after birth.
The process of myelination, the formation of the insulating myelin sheath around
some axons, begins in the brain before birth and continues into early adulthood. As
noted earlier, a crucial function of myelin is to increase the speed of neural conduc-
tion. Myelination begins deep in the brain, beginning with the brainstem, and moves
upward and outward into the cortex at a fairly steady rate throughout childhood and
adolescence and into early adulthood (Lenroot & Giedd, 2006). The various cortical
areas thus become myelinated at very different rates, possibly contributing to the dif-
ferent rates of development for various behaviors.
This pattern diverges in interesting ways from the pattern found in our primate
relative, the chimpanzee. Initially, white matter develops even more slowly in the
prefrontal lobes of infant and juvenile chimpanzees than it does in young humans,
suggesting one possible mechanism whereby evolutionary pressure has improved
human brain function relative to that of other primates (Sakai et al., 2011). Interest-
ingly, however, the chimpanzee shows a mature pattern of myelination at the point
of sexual maturity, far earlier than that observed in humans (D. J. Miller et al., 2012).
The reasons for the extended period of human myelination remain unknown, and
might be both positive (facilitating improvements in executive functions after sexual
maturity) and negative (making the human brain more vulnerable to disorders re-
lated to myelination discussed on pages 107–108).
Synaptogenesis
One result of the extraordinary growth of axonal and dendritic fibers is a wildly exu-
berant generation of neuronal connections. In a process called synaptogenesis, each
neuron forms synapses with thousands of others, resulting in the formation of the
trillions of connections referred to earlier. Figure 3.8 shows the time course of synap-
togenesis in the cortex. As you can see, it begins prenatally and proceeds very rapidly
2 yrs.
Age
BirthConception 4 yrs. 10 yrs.
Less
dense
More
dense
S
yn
ap
ti
c
d
en
si
ty
Adolescence Adult
Adolescence
Visual CortexPrefrontal Cortex
FIGURE 3.8 Synapse production and
elimination Mean synaptic density (the
number of synapses in a given space) first
increases sharply as new synapses are
overproduced and later declines gradu-
ally as excess synapses are eliminated.
Note that the time scale is compressed at
later stages. (From p. r. huttenlocher &
Dabholkar, 1997)
myelination n the formation of myelin
(a fatty sheath) around the axons of
neurons that speeds and increases
information-processing abilities
synaptogenesis n the process by which
neurons form synapses with other neu-
rons, resulting in trillions of connections

B R A I N D E V E L O P M E N T n 113
both before birth and for some time afterward. Note that both the timing and rate
of synapse production vary for different cortical areas; synapse generation is com-
plete much earlier in the visual cortex, for example, than in the frontal area. As with
myelination, the differential timing of synapse generation across areas of the brain
likely contributes to the developmental timing of the onset of various abilities and
behaviors.
Synapse Elimination
The explosive generation of neurons and synapses during synaptogenesis, which is
largely under genetic control, results in a huge surplus—many more neural connec-
tions than any one brain can use. This overabundance of synapses includes an ex-
cess of connections between different parts of the brain: for instance, many neurons
in what will become the auditory cortex are linked with those in the visual area, and
both of these areas are overly connected to neurons involved in taste and smell. As
a consequence of this hyperconnectivity, newborns may experience synesthesia—
the blending of different types of sensory input (Maurer & Mondloch, 2004). In
the case of the extra connections between auditory and visual cortex, for example,
auditory stimulation may produce a visual experience, with the infant’s perceiving
a sound as being of a particular color.
We now come to what is one of the most remarkable facts about the develop-
ment of the human brain. Approximately 40% of this great synaptic superfluity gets
eliminated in a developmental process known as synaptic pruning. As you learned
in the previous chapter, cell death is a normal part of development, and nowhere is
that more evident than in the systematic pruning of excess synapses that continues
for years after birth. This pruning occurs at different times in different areas of the
brain (P. R. Huttenlocher & Dabholkar, 1997). You can see from Figure 3.8 that
the elimination of synapses in the visual cortex begins near the end of the first year
of life and continues until roughly 10 years of age, whereas synapse elimination in
the prefrontal area shows a slower time course. During peak pruning periods, as
many as 100,000 synapses may be eliminated per second (Kolb, 1995)!
Not known until fairly recently is the fact that the brain undergoes explosive
changes during adolescence, including a wave of overproduction and pruning akin
to that in the first years of life (Giedd et al., 1999; Gogtay et al., 2004). Although
the amount of white matter in the cortex shows a steady increase from childhood
well into adulthood, the amount of gray matter increases dramatically starting
around 11 or 12 years of age. The increase in gray matter proceeds rapidly, peaks
around puberty, and then begins to decline as some of it is replaced by white matter
(see Figure 3.9). The last area of the cortex to mature is the dorsolateral prefrontal
cortex, which is vital for regulating attention, controlling impulses, foreseeing con-
sequences, setting priorities, and other executive functions. It does not reach adult
dimensions until after the age of 20.
You will notice that Figure 3.8 does not show a second proliferation and reduc-
tion of synaptic density in adolescence. One of the reasons for this is that the figure
is based on cross-sectional research in which the brains of individuals of different
ages were examined only at autopsy. The new data showing substantial develop-
ment in the adolescent brain come from longitudinal studies in which the same in-
dividuals’ brains were scanned repeatedly over several years. The dramatic changes
that appear in individuals were not evident when the brains of separate groups of
different ages were studied. (See the discussion of developmental research designs
in Chapter 1, pages 32–33.)
synaptic pruning n the normal devel-
opmental process through which synapses
that are rarely activated are eliminated

114 n chapTer 3 BIOLOGY AND BEHAVIOR
The Importance of Experience
What factors determine which of the brain’s excess synapses will be pruned and
which maintained? Experience plays a central role in what is essentially a case of
“use it or lose it.” In a competitive process that has been dubbed “neural Darwin-
ism” (Edelman, 1987), those synapses that are frequently activated are selectively
preserved (Changeux & Danchin, 1976). The more often a synapse is activated, the
stronger the connection becomes between the neurons involved: in short, neurons
that fire together wire together (Hebb, 1949). Conversely, when a synapse is rarely
active, it is likely to disappear: the axon of one neuron withdraws and the dendritic
spine of the other is “pruned away.”
The obvious question now is: Why does the human brain—the product of mil-
lions of years of evolution—take such a devious developmental path, producing a
huge excess of synapses, only to get rid of a substantial proportion of them? The an-
swer appears to be evolutionary economy. The capacity of the brain to be molded or
changed by experience, referred to as plasticity, means that less information needs
to be encoded in the genes. This economizing may, in fact, be a necessity: the num-
ber of genes involved in the formation and functioning of the nervous system is
enough to specify only a very small fraction of the normal complement of neurons
and neural connections. In addition, if brain structures were entirely hard-wired,
organisms would be unable to adapt to their postnatal environment. To complete
the final wiring of the brain, nurture joins forces with nature.
The collaboration between nature and nurture in building the brain occurs dif-
ferently for two kinds of plasticity. One kind involves the general experiences that
almost all infants have just by virtue of being human. The second kind involves
specific, idiosyncratic experiences that children have as a result of their particular
life circumstances—such as growing up in the United States or in the Amazon rain
forest, experiencing frequent cuddling or abuse, being an only child or one of many
siblings, and so on.
plasticity n the capacity of the brain to
be affected by experience
FIGURE 3.9 Brain maturation
These views of the right side and
top of the brain of 5- to 20-year-
olds illustrate maturation over the
surface of the cortex. The averaged
MrI images come from participants
whose brains were scanned repeat-
edly at 2-year intervals. The bluer
the image, the more mature that part
of the cortex is (i.e., the more gray
matter has been replaced with white
matter). Notice that the parts of the
cortex associated with more basic
functions (i.e., the sensory and motor
areas toward the back) mature ear-
lier than the areas involved in higher
functions (i.e., attention, executive
functioning). Notice particularly that
the frontal areas, involved in executive
functioning, approach maturity only
in early adulthood. (From Gogtay et
al., 2004)

B R A I N D E V E L O P M E N T n 115
Experience-Expectant Processes
William Greenough refers to the role of general human experience in shaping brain
development as experience-expectant plasticity. According to this view, the nor-
mal wiring of the brain is in part a result of the kinds of general experiences that
have been present throughout human evolution, experiences that every human with
an intact sensory-motor system who inhabits a reasonably normal environment
will have: patterned visual stimulation, voices and other sounds, movement and
manipulation, and so forth (Greenough & Black, 1992). Consequently, the brain
can “expect” input from these reliable sources to fine-tune its circuitry; synapses
that are frequently activated will be strengthened and stabilized and those that are
rarely activated will be “pruned.” Thus, our experience of the external world plays
a fundamental role in shaping the most basic aspects of the structure of our brain.
One fundamental benefit of experience-expectant plasticity is that, because experi-
ence helps shape the brain, fewer genes need to be dedicated to normal development.
Another is that the brain is better able to recover from injury to certain areas, because
other brain areas can take over the function that would have been performed by the
damaged area. The younger the brain when damaged, the more likely recovery is.
The downside of experience-expectant plasticity is that it is accompanied by vul-
nerability. If for some reason the experience that the developing brain is “expecting”
for fine-tuning its circuits does not occur, whether because of inadequate stimu-
lation or impaired sensory receptors, development may be compromised. A good
example of this vulnerability comes from children who are born with cataracts that
obscure their vision. The longer a cataract remains in place after birth, the more
impaired the child’s visual acuity will be once it is removed. Dramatic improvement
typically follows early removal, although some aspects of visual processing (espe-
cially of faces) remain affected even into adulthood (de Heering & Maurer, 2012;
Maurer, Mondloch, & Lewis, 2007). Presumably, the lasting deficits of late cataract
removal occur because synapses that would normally have been activated by visual
stimulation after birth were pruned because of the lack of that stimulation.
When an expected form of sensory experience is absent, what happens to areas
of the brain that normally would have become specialized as a result of that experi-
ence? A wealth of data from animals indicates that such areas can become at least
partially reorganized to serve some other function. Evidence of such plasticity and
reorganization in humans comes from studies of congenitally deaf adults who, as
children, had learned American Sign Language, a full-fledged, visually based, lan-
guage (Bavelier, Dye, & Hauser, 2006; Bavelier & Neville, 2002). Deaf individuals
rely heavily on peripheral vision for language processing; they typically look into
the eyes of a person who is signing to them, while using their peripheral vision to
monitor the hand and arm motions of the signer. ERP recordings of brain activ-
ity (see Box 3.3) showed that deaf individuals’ responses to peripheral visual stimuli
are several times stronger than those of hearing people. In addition, their responses
are distributed differently across brain regions. Thus, because of the lack of audi-
tory experience, brain systems that would normally be involved in hearing and in
spoken-language processing become organized to process visual information instead.
Similar evidence of early brain reorganization comes from research with blind
adults. When tested for their ability to discriminate changes in musical pitch, adults
who were born blind or became blind quite early performed much better than those
who had become blind later in life (Gougoux et al., 2004). Presumably, connections
between visual and auditory cortex were preserved in individuals with early-onset
blindness, giving them extra “brain power” to apply to the auditory task. Consis-
tent with this idea, brain-imaging research suggests that parts of the visual cortex
experience-expectant plasticity n the
process through which the normal wiring
of the brain occurs in part as a result
of experiences that every human who
inhabits any reasonably normal environ-
ment will have

116 n chapTer 3 BIOLOGY AND BEHAVIOR
contribute to superior sound localization ability in adults with early-onset blind-
ness. A related result is that congenitally blind individuals show activation in the
“visual” cortex both when reading Braille (Sadato et al., 1998) and when processing
spoken language (Bedny et al., 2011).
Sensitive periods As suggested by the foregoing examples, a key element in
experience-expectant plasticity is timing. There are a few sensitive periods when
the human brain is especially sensitive to particular kinds of external stimuli. It is
as though a time window were temporarily opened, inviting environmental input to
help organize the brain. Gradually, the window closes. The neural organization that
occurs (or does not occur) during sensitive periods is typically irreversible.
As discussed in Chapter 1, the extreme deprivation that the Romanian orphans
suffered early in life, when children normally experience a wealth of social and
other environmental stimulation, is considered by some to be an example of a
sensitive-period effect. Some investigators speculate that adolescence, during which
rapid changes are occurring in the brain, may be another sensitive period for various
aspects of development. Yet another sensitive period, for language learning, will be
discussed in Chapter 6.
Experience-Dependent Processes
The brain is also sculpted by idiosyncratic experience through what Greenough
calls experience-dependent plasticity. Neural connections are created and re-
organized constantly, throughout life, as a function of an individual’s experiences.
(If you remember anything of what you have been reading in this chapter, it’s be-
cause you have formed new neural connections.)
Much of the research on experience-dependent plasticity has
been focused on nonhuman animals, whose environments can be
readily manipulated. One such method has involved comparisons
between animals reared in complex environments full of objects
to explore and use versus animals reared in bare laboratory cages.
The brains of rats (and cats and monkeys) that grow up in a com-
plex environment have more dendritic spines on their cortical
neurons, more synapses per neuron, and more synapses overall, as
well as a generally thicker cortex and more of the supportive tis-
sues (such as blood vessels and glial cells) that maximize neuro-
nal and synaptic function. All this extra hardware seems to have a
payoff: rats (and other animals) reared in a complex environment
(which is more akin to their natural environment) perform better
in a variety of learning tasks than do their counterparts raised in
bare cages (e.g., Sale, Berardi, & Maffei, 2009).
Highly specific effects of experience on brain structure also
occur. For example, rats that are trained to use just one forelimb
to get a food reward have increased dendritic material in the par-
ticular area of the motor cortex that controls the movement of
the trained limb (Greenough, Larson, & Withers, 1985). In hu-
mans, research on musicians has revealed that, compared with a
control group, violinists and cellists had increased cortical rep-
resentation of the fingers of the left hand (Elbert et al., 1995).
In other words, after years of practice, more cortical cells were
devoted to receiving input from and controlling the fingers that
manipulate the strings of the instruments. Similarly, in skilled
experience-dependent plasticity n
the process through which neural con-
nections are created and reorganized
throughout life as a function of an indi-
vidual’s experiences
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as a result of growing up in a complex
environment full of stimulating objects to
explore and challenges to master, the brains
of the rats in the top photo will contain
more synapses than if they had been reared
in unstimulating laboratory cages (bottom
photo).

WWW.RATWHISPERER.NET

B R A I N D E V E L O P M E N T n 117
Braille readers, the cortical representation of the left hand—which is used to read
Braille text—is enlarged (Pascual-Leone et al., 1993).
Effects of specific experience are also evident in fMRI studies of individuals with
dyslexia, a severe reading problem in people with normal intelligence and schooling
(see Chapter 8). One example involves a remedial reading program in which 2nd-
and 3rd-graders with dyslexia received training in recognizing the correspondence
between speech sounds and letters (Blachman et al., 2004). After the training, not
only did the children show marked improvement in their reading ability, but fMRI
imaging revealed increased activity in their left-brain areas that was similar to the
activity in the brains of good readers. The specific effects of one’s reading experience
also show up in the fact that reading Chinese characters recruits distinctly different
brain networks than those involved in reading an alphabetic script (such as English).
Brain Damage and Recovery
As noted previously, because of its plasticity (especially early in life), the brain can
become rewired—at least to some degree—after suffering damage. Children who
suffer from brain damage thus have a better chance of recovering lost function
than do adults who suffer similar damage. The strongest evidence for this comes
from young children who suffer damage to the language area of the cortex and who
generally recover most, if not all, of their language functions. This is because after
the damage has occurred, other areas of the immature brain can take over language
functions. As a result, language is largely spared, though specific linguistic impair-
ments may remain (e.g., Zevin, Datta, & Skipper, 2012).
In contrast, adults who sustain the same type of brain damage undergo no such
reorganization of language functions and may have a permanent loss in the ability
to comprehend or produce speech. Greater recovery from early brain injury has also
been observed for functions other than language. For example, producing appropri-
ate facial expressions is more difficult for adults who had damage to the frontal area
of the cortex during adulthood than for adults whose frontal lobe injury occurred
in childhood (Kolb, 1995).
It is not always true, however, that the chance of recovery from early brain in-
jury is greater than it is for later injury. Likelihood of recovery depends on how
extensive the damage is and what aspect of brain development is occurring at the
time of the damage. Consider, for example, the offspring of Japanese women who,
while pregnant, were exposed to massive levels of radiation from the atomic bombs
dropped on Hiroshima and Nagasaki in 1945. The rate of intellectual impairment
D
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how would the cortical representations of
their fingers be likely to differ for these two
professional musicians?

118 n chapTer 3 BIOLOGY AND BEHAVIOR
was much higher for surviving children whose exposure had occurred very early in
prenatal development, during the time of rapid neurogenesis and migration of neu-
rons (Otake & Schull, 1984). Similarly, brain injury during early childhood gener-
ally results in more severe cognitive impairment in IQ than does later comparable
injury (V. Anderson et al., 2012).
Furthermore, even when children appear to have made a full recovery from an
early brain injury, deficits may emerge later. This was demonstrated in a cross-
sectional study that compared cognitive performance in a group of children who
had been born with cerebral damage and a control group of children with no brain
damage (Banich et al., 1990). As Figure 3.10 shows, the children with brain damage
did not differ from the control group in their performance on two subscales of an IQ
test at 6 years of age. However, as the normal children’s performance improved with
age, the brain-damaged children’s performance fell progressively behind. The same
pattern of results—decline in IQ over age for children with brain damage—was also
demonstrated in a longitudinal study, in which children who had sustained early
damage were tested before and after age 7 (S. C. Levine et al., 2005). These results
illustrate the difficulty of predicting the development of children with cerebral inju-
ries: behavior that appears normal early in development may deteriorate.
On the basis of these various aspects of plasticity, we can generalize that the
worst time to suffer brain damage is very early, during prenatal development and
the first year after birth, when neurogenesis is occurring and basic brain structures
are being formed. Damage at this point may have cascading effects on subsequent
aspects of brain development, with potentially wide-ranging negative effects. In
contrast, when brain damage is sustained in early childhood—that is, when synapse
generation and pruning are occurring and plasticity is highest—the chances for the
brain’s rewiring itself and recovering lost function are best.
review:
Nature and nurture cooperate in the construction of the human brain. Some important brain
structures include the neurons, which communicate with one another at synapses; the cortex,
in which different functions are localized in different areas; and the cerebral hemispheres,
which are specialized for different kinds of processing. The processes involved in the devel-
opment of the brain include neurogenesis and synaptogenesis, followed by the systematic
elimination of some synapses and the preservation of others as a function of experience.
Two forms of plasticity contribute to the development of behavior. As a result of
experience-expectant plasticity, the brain is shaped by experiences that are available to every
Age at testing
Vocabulary
(a)
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16 18141210864
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Congenital lesion
Congenital lesion
Control Control
FIGURE 3.10 emergent effects of early
brain damage at 6 years of age, children
with congenital brain damage scored the
same as normal children on two subscales of
an intelligence test. however, the children
with brain damage failed to improve and
fell progressively farther behind the normal
children, so that by adolescence there were
large differences between the two groups.
(Data from Banich et al., 1990; figure from
Kolb, 1995)

T H E B O D Y : P H Y S I C A L G R O W T H A N D D E V E L O P M E N T n 119
typically developing individual in interaction with every species-typical environment. Through
experience-dependent plasticity, the brain is also structured by an individual’s idiosyncratic
life experiences. Because of the importance of experience in brain development, sensitive
periods exist during which specific experience must be present for normal development. Tim-
ing is also a crucial factor in the ultimate impact of brain damage.
The Body: Physical Growth and Development
In Chapter 1, we emphasized the multiple contexts in which development occurs.
Here we focus on the most immediate context for development—the body itself.
Everything we think, feel, say, and do involves our physical selves, and changes in
the body lead to changes in behavior. In this section, we present a brief overview
of some aspects of physical growth, including some of the factors that can disrupt
normal development. Nutritional behavior, a vital aspect of physical development,
is featured as we consider the regulation of eating. We concentrate particularly on
one of the consequences of poor regulation—obesity. Finally, we focus on the op-
posite problem—undernutrition.
Growth and Maturation
Compared with most other species, humans undergo a prolonged period of physi-
cal growth. The body grows and develops for 20% of the human life span, whereas
mice, for example, grow during only 2% of their life span. Figure 3.11 shows the
most obvious aspects of physical growth: we get 3 times taller and 15 to 20 times
heavier between birth and age 20. The figure shows averages, of course, and there
Age (in years)
A
ve
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2018161412108642
Age (in years)
2018161412108642
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97%
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Girls
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24
FIGURE 3.11 Growth curves These
growth curves for height and weight from
ages 2 to 20 years are based on large
national samples of children from across
the United States. each curve indicates the
percent of the reference population that
falls below the indicated weight and height.
(centers for Disease control and prevention,
2002)

120 n chapTer 3 BIOLOGY AND BEHAVIOR
are obviously huge individual differences in height and weight, as well as in the
timing of physical development.
Growth is uneven over time, as you can tell from the differences in the slopes in
Figure 3.11. The slopes are steepest when the most rapid growth is occurring—in
the first 2 years and in early adolescence. Early on, boys and girls grow at roughly
the same rate, and they are essentially equal in height and weight until around 10
to 12 years of age. Then girls experience their adolescent growth spurt, at the end of
which they are somewhat taller and heavier than boys. (Remember those awkward
middle-school years when the girls towered over the boys, much to the discomfort
of both?) Adolescent boys experience their growth spurt about 2 years after the
girls, permanently passing them in both height and weight. Full height is achieved,
on average, by around the age of 15½ for girls and 17½ for boys.
Growth is also uneven across the different parts of the body. Following the prin-
ciple of cephalocaudal development described in Chapter 2 (page 48), the head re-
gion is initially relatively large—fully 50% of body length at 2 months of age—but
only about 10% of body length in adulthood. The gawkiness of young adolescents
stems in part from the fact that their growth spurt begins with dramatic increases
in the size of the hands and feet; it’s easy to trip over your own feet when they are
disproportionately larger than the rest of you.
Body composition also changes with age. The proportion of body fat is highest
in infancy, gradually declining thereafter until around 6 to 8 years of age. In adoles-
cence, it decreases in boys but increases in girls, and that increase helps trigger the
onset of menstruation. The proportion of muscle grows slowly until adolescence,
when it increases dramatically, especially in boys.
Variability
There is great variability across individuals and groups in all aspects of physical de-
velopment. This variability in physical development is due to both genetic and en-
vironmental factors. Genes affect growth and sexual maturation in large part by
influencing the production of hormones, especially growth hormone (secreted by the
pituitary gland) and thyroxine (released by the thyroid gland). The influence of envi-
ronmental factors is particularly evident in secular trends, marked changes in physi-
cal development that have occurred over generations. In contemporary industrialized
nations, adults are several inches taller than their same-sex great-grandparents were.
This change is assumed to have resulted primarily from improvements in nutrition
and general health. Another secular trend in the United States today involves girls’
beginning to menstruate a few years earlier than their ancestors did, a change attrib-
uted to the general improvement in nutritional status of the population.
Environmental factors can also play a role in disturbances of normal growth. For
example, severe chronic stress, such as that associated with a home environment
involving serious marital discord, alcoholism, or child abuse can impair growth by
lowering the pituitary gland’s production of growth hormone (Powell, Brasel, &
Blizzard, 1967). Children raised in institutions also have a higher risk of growth
impairment, likely due to the combination of social stressors and poor nutrition
(D. E. Johnson & Gunnar, 2011). A combination of genetic and environmental
factors is apparently involved in failure to thrive, a condition in which infants be-
come malnourished and fail to grow or gain weight for no obvious medical reason.
Because the reason for a particular infant’s failure to thrive is often difficult to de-
termine, treatment may range from hospitalization to dietary supplementation to
behavioral interventions, such as rewards for positive eating behaviors ( Jaffe, 2011).
secular trends n marked changes in
physical development that have occurred
over generations
failure to thrive n a condition in which
infants become malnourished and fail to
grow or gain weight for no obvious med-
ical reason

T H E B O D Y : P H Y S I C A L G R O W T H A N D D E V E L O P M E N T n 121
Nutritional Behavior
The health of our bodies depends on what we put into them, including the amount
and kind of food we eat. Thus, the development of eating or nutritional behavior is
a crucial aspect of child development from infancy onward.
Infant Feeding
Like all mammals, human newborns obtain life-sustaining nourishment through
suckling, although they require more assistance in this endeavor than do most other
mammals. Throughout nearly the entire history of the human species, the only or
primary source of nourishment for infants was breast milk. Mother’s milk has many
virtues ( J. Newman, 1995). It is naturally free of bacteria, strengthens the infant’s
immune system, and contains the mother’s antibodies against infectious agents the
baby is likely to encounter after birth.
There have also been suggestions in the literature that the fatty acids in breast
milk have a positive effect on cognitive development, with some studies indicating
higher IQ scores for children and adults who were breastfed as infants (for review,
see Nisbett et al., 2012). The challenge in this area of research in the United States
is that the choice to breastfeed is correlated with social class (due to factors rang-
ing from maternal education to working conditions that make it difficult to nurse
or pump breast milk on the job). However, several recent studies that controlled
for social class still found cognitive benefits associated with breastfeeding. In one
of those studies, mother–infant dyads were randomly assigned either to an inter-
vention encouraging breastfeeding or to a control condition without intervention.
The results indicated that prolonged and exclusive breastfeeding in infancy led to
increased IQ scores at 6½ years of age (Kramer et al., 2008). Another study that
examined genetic factors found that children who carry one of two specific alleles
that regulate fatty acids showed a substantial cognitive benefit from breastfeed-
ing, while individuals with a different allele showed a smaller benefit (Caspi et
al., 2007). These results reflect the kind of genotype–environment interaction dis-
cussed earlier in this chapter, with the benefits of a particular environment (in this
case, breast milk) delimited by the child’s genotype.
However, in spite of the well-established nutritional superiority of breast milk,
as well as the fact that it is free, many infants in the United States are exclusively
or predominantly formula-fed. Recent public health efforts have begun to shift this
longtime feeding trend, by educating parents about the benefits of breast milk and
encouraging employers to provide private space for working mothers to pump breast
milk. Since these efforts were initiated, the number of newborns fed breast milk in
the United States has increased annually and, by 2009, had risen to 76.9% of neo-
nates (Centers for Disease Control and Prevention, 2012). However, this good nu-
tritional start was difficult for parents to maintain; by 6 months of age, only 47.2%
of infants were still being breastfed, and by 12 months of age, only 25.5% were.
In developed countries, infant formula can support normal growth and devel-
opment, although infants who are formula-fed have somewhat higher rates of in-
fection than do those who are fed breast milk. In undeveloped countries, however,
formula feeding can exact a costly toll. Much of the undeveloped world does not
have safe water, so infant formula is often mixed with polluted water in unsanitary
containers. Furthermore, poor, uneducated parents often dilute the formula in an
effort to make the expensive powder last longer. In such circumstances, parents’
attempts to promote the health of their babies end up having the opposite effect
(Popkin & Doan, 1990).
By breastfeeding her infant, this mother is
providing her baby with many benefits that
are not available in formula.
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122 n chapTer 3 BIOLOGY AND BEHAVIOR
Development of Food Preferences and the Regulation of Eating
Food preferences are a primary determinant of what we eat throughout life, and some
of these preferences are clearly innate. Infants display some of the same reflexive fa-
cial expressions that older children and adults display in response to three basic tastes:
sweet, sour, and bitter. The first produces a hint of a smile; the second, a pucker; the
third, a grimace (Rosenstein & Oster, 1988; Steiner, 1979). Newborns’ strong prefer-
ence for sweetness is reflected both in their smiling in response to sweet flavors and
in the fact that they will drink larger quantities of sweetened water than plain water.
These innate preferences may have an evolutionary origin, since poisonous substances
are often bitter or sour but almost never sweet. At the same time, recall from Chapter
2 (page 53) that taste preferences can also be influenced by the prenatal environment,
suggesting an important role for experience even in the earliest flavor preferences.
Infants’ taste sensitivity is evident in their reactions to their mother’s milk,
which can take on the flavor of what she eats. Babies nurse longer and take more
breast milk when their mother has ingested either garlic or vanilla flavors, but
they drink less breast milk after she has downed a beer (Mennella & Beauchamp,
1993a, 1993b, 1996).
From infancy on, experience has a major influence on what foods children like
and dislike and on what and how much they eat. For instance, preschool children’s
liking for particular foods increases if they observe other children enjoying them
(Birch & Fisher, 1996). Children’s eating is also influenced by what foods their
parents encourage and discourage. This influence does not always work in the way
the parents intend, however. For example, standard parental strategies of cajoling
and bribing young children to eat new or healthier foods—“If you eat your spinach,
you can have some ice cream”—can be doubly counterproductive. The most prob-
able result is that the child will dislike the healthy food even more and have an even
stronger preference for the sweet, fatty food used as a reward (Birch & Fisher, 1996).
Many parents become needlessly concerned with how much their young chil-
dren eat. They might, however, put less effort into trying to control their children’s
eating behavior if they realized that young children are actually quite good at regu-
lating the amount of food they consume. Research has shown that preschool chil-
dren adjust how much they eat at a given time based on how much they consumed
earlier. For example, children were found to eat less for lunch if they had been
served a snack earlier than if they had not had the snack (Birch & Fisher, 1996).
(In contrast, a group of adults ate pretty much the same amount of a meal whether
or not they had been served a snack earlier.)
In general, children whose parents try to control their eating habits tend to be
worse at regulating their food intake themselves than are children whose parents
allow them more control over what and how much they eat (S. L. Johnson & Birch,
1994). Parents’ overregulation of their children’s eating behavior can have continu-
ing effects. Adults who reported that their parents used food to control their be-
havior were more likely to be struggling with their weight and with binge eating
(Puhl & Schwartz, 2003).
Obesity
So many people have difficulty regulating their eating appropriately that the most
common dietary problems in the United States are related to overeating and its
many consequences. In an epidemic of obesity, one-third of American adults are
currently considered obese (Ogden et al., 2012). It is an increasing problem, not just
among Americans but also among indigenous people in many developing coun-
tries (Abelson & Kennedy, 2004). This situation exists largely because societies

T H E B O D Y : P H Y S I C A L G R O W T H A N D D E V E L O P M E N T n 123
all over the world are increasingly adopting
a “Western diet” of foods high in fat and
sugar and low in fiber. Fast-food restaurants
have proliferated around the globe; indeed,
after Santa Claus, Ronald McDonald is the
second most recognized figure worldwide
(K. Brownell, 2004).
The proportion of American children and
adolescents who are overweight has tripled in
the past four decades (see Figure 3.12), with
the increase being greatest for Latinos and Af-
rican Americans. The outlook for these heavy
children is troubling, because they are likely
to struggle with weight problems through-
out their lives. Furthermore, there is a good
chance they will adopt a variety of unhealthy
measures to fight their weight problems—
skipping meals, fasting, smoking, taking diet
pills, and even undergoing liposuction—all of
which can lead to further health problems.
Two important questions need to be addressed: Why do some people but not
others become overweight, and why is there an epidemic of obesity? Both genetic
and environmental factors play roles. Genetic factors are reflected in the findings
that (1) the weight of adopted children is more strongly correlated with that of their
biological parents than with that of their adoptive parents, and (2) identical twins,
including those reared apart, are more similar in weight than fraternal twins are
(Plomin et al., 2013). Even the speed of eating, which is related both to how much
is eaten in a given meal and to the weight of the eater, shows substantial heritabil-
ity (Llewellyn et al., 2008). Thus, genes affect individuals’ susceptibility to gaining
weight and how much food they eat in the first place, making it relatively difficult or
easy for them to avoid becoming part of the obesity epidemic.
Environmental influences also play a major role in this epidemic, as is obvious
from the fact that a much higher proportion of the population of the United States
is overweight now than in previous times. Indeed, some have argued that becoming
obese in the United States could be considered a normal response to the contempo-
rary American taste for high-fat, high-sugar foods
in ever larger portion sizes (K. D. Brownell, 2003).
A host of other factors fuel the ever expanding
waistlines of today’s children. Children spend less
time playing outside than their counterparts did in
previous generations: fully half of today’s preschool-
aged children spend less than an hour a day engaged
in outdoor play (Tandon et al., 2012). Children
today also get less exercise because they rarely walk
or bike to school. At school, they frequently have
no physical education programs or recess activities
and often purchase cafeteria lunches consisting of
high-fat foods (e.g., pizza, hamburgers) and high-
calorie soft drinks. Young couch potatoes—many
of whom spend more than 5 hours a day in front of
the TV consuming junk food as they are subjected
to a barrage of advertisements for more high-fat,
This photo clearly reflects the genetic
aspects of the problem of obesity. The ice
cream cone is emblematic of the environ-
mental factors that may contribute to it.
C
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Years
6–11 years
12–19 years
2–5 years
1963–65 1971–74 1976–80 1988–94 1999–00 2003–42001–21966–70
FIGURE 3.12 Overweight—a growing
problem The proportion of children in the
United States who are overweight has tripled
in the past four decades.
Source: National Health Examination Surveys II (Ages 6–11) and III (Ages
12–17), 1999–2004

124 n chapTer 3 BIOLOGY AND BEHAVIOR
nonnutritious fast food—are much more likely to be obese than
are children who watch for 2 hours or fewer (T. N. Robinson,
2001). In addition, many U.S. families often dine out at fast-food
or “all you can eat” buffet-style restaurants where they consume
large portions of relatively high-calorie foods (Krishnamoorthy,
Hart, & Jelalian, 2006). Finally, unhealthy foods are often less
expensive and more readily available than healthier foods, espe-
cially in inner-city areas that lack full-service supermarkets. In
such areas, known as “food deserts,” poorer residents often must
rely on convenience stores that stock primarily high-calorie pre-
packaged foods, making it difficult even for motivated parents to
provide healthy foods to their children.
Obesity puts children and adolescents at risk for a wide variety
of serious health problems, including heart disease and diabetes.
In addition, many obese youth suffer the consequences of nega-
tive stereotypes and discrimination in a variety of areas, even col-
lege admissions (M. A. Friedman & Brownell, 1995). Overweight
children and teenagers suffer a variety of other social problems as
well. For example, overweight adolescents tend to be either socially
isolated or on the fringe of their social networks (Strauss & Pol-
lack, 2003). Also, in a large-scale survey of middle school and high school students,
teens who reported being teased about their weight had considered suicide more often
than had their slimmer peers (M. Eisenberg, Neumark-Sztainer, & Story, 2003).
There is, unfortunately, no easy cure for obesity in children. However, some hope
for the general obesity problem comes from the fact that public awareness is now
focused on the severity of the problem and the variety of factors that contribute to
it. Many schools have begun serving more nutritious, less caloric foods, including
those available in vending machines, and fast-food chains have begun to include at
least some low-calorie options on their menus. Prominent national figures, such as
First Lady Michelle Obama, have targeted childhood obesity as a key public health
issue, raising hope that campaigns focused on healthy eating and exercise will help
families make positive lifestyle choices. Another helpful step, proposed by the In-
stitute of Medicine (2004), would be for the food, beverage, and entertainment in-
dustries to discontinue targeting their advertising of high-fat, high-sugar foods and
drinks to children and adolescents.
Undernutrition
At the same time that many people in relatively rich countries are overeating their
way to poor health, the health of people in developing nations is compromised by
their not getting enough to eat. Fully one-fourth of all children (and 40% of those
younger than 5) living in these countries are undernourished. The nutritional defi-
cits they experience can involve an inadequate supply of total calories, of protein, of
vitamins and minerals, or any combination of these deficiencies. Severe malnutri-
tion of infants and young children is most common in developing and/or war-torn
countries. Analyses of child mortality data suggest that suboptimum nutrition (in-
cluding nonexclusive breastfeeding) is an underlying cause of 35% of child deaths
worldwide (R. E. Black et al., 2008).
Undernutrition and malnutrition are virtually always associated with poverty
and myriad related factors, ranging from limited access to health care (the primary
cause in the United States) to warfare, famine, and natural disasters. The interac-
tion of malnutrition with poverty and other forms of deprivation adversely affects
By exercising together, this father and son
may be taking one of the most effective
steps they can toward weight control.
M
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T H E B O D Y : P H Y S I C A L G R O W T H A N D D E V E L O P M E N T n 125
all aspects of development. Figure 3.13 presents a model of how the complex in-
teraction of these multiple factors impairs cognitive development ( J. L. Brown &
Pollitt, 1996). As you can see, malnutrition can have direct effects on the structural
development of the brain, general energy level, susceptibility to infection, and
physical growth. With inadequate energy, malnourished children tend to reduce
their energy expenditure and withdraw from stimulation, making them quiet and
passive in general, less responsive in social interactions, less attentive in school,
and so on. Apathy, slowed growth, and delayed development of motor skills also
retard the children’s exploration of the environment, further limiting their oppor-
tunities to learn.
Can anything be done to help malnourished and undernourished youngsters?
Because so many interacting factors are involved in the problem, addressing it ef-
fectively is not easy—but neither is it impossible, as shown by several large-scale
intervention efforts throughout the world. For example, in one long-term proj-
ect led by Ernesto Pollitt in Guatemala, a high-protein dietary supplement ad-
ministered starting in infancy correlated with an increase in performance on tests
of cognitive functioning in adolescence (Pollitt et al., 1993). Follow-ups on the
participants in adulthood produced strong evidence for the continuing benefits
of dietary supplements 25 years after the intervention (Maluccio et al., 2009).
Although it is possible to improve the developmental status of malnourished
children, it would be better, both for the children themselves and for society in
general, to prevent the occurrence of malnutrition in the first place. As Brown and
Pollitt (1996) note: “On balance, it seems clear that prevention of malnutrition
among young children remains the best policy—not only on moral grounds but
on economic ones as well” (p. 702).
Brain damage
(sometimes reversible)
Delayed
intellectual
development
Minimal
exploration
of environment
Lethargy and
withdrawal
Malnutrition Illness
Delayed physical
growth
Lack of educational
and medical resources
Poverty
Delayed development
of motor skills such
as crawling and walking
Lowered
expectations
of child from
adults because
child appears
young
FIGURE 3.13 Malnutrition and cogni-
tive development Malnutrition, combined
with poverty, affects many aspects of devel-
opment and can lead to impaired cognitive
abilities. (From J. L. Brown & pollitt, 1996)

126 n chapTer 3 BIOLOGY AND BEHAVIOR
review:
Sound nutritional behavior is vital to general health. Preferences for certain foods are evident
from birth on, and, as children develop, what they choose to eat is influenced by many factors,
including the preferences of their friends and their parents’ attempts to influence their eating
behavior. Obesity among both adults and children has increased dramatically in the United
States and much of the rest of the world in recent decades, as exposure to rich foods in large
portions has increased and physical activity has decreased. However, throughout the world, the
most common nutritional problem is undernutrition, which is very closely associated with pov-
erty. The combination of malnutrition and poverty is particularly devastating to development.
chapter summary:
Nature and Nurture
n The complex interplay of nature and nurture was the constant
theme of this chapter. In the drama of development, genotype,
phenotype, and environment all play starring roles, and the
plot moves forward as they interact in many obvious and many
not-so-obvious ways.
n The starting point for development is the genotype—the genes
inherited at conception from one’s parents. Only some of those
genes are expressed in the phenotype, one’s observable charac-
teristics. Whether some genes are expressed at all is a function
of dominance patterns. Most traits studied by developmental
scientists are influenced by multiple genes. The switching on
and off of genes over time underlies many aspects of develop-
ment. This process is affected by experience via methylation.
n The eventual outcome of a given genotype is always contin-
gent on the environment in which it develops. Parents and
their behavior toward their children are a salient part of the
children’s environment. Parents’ behavior toward their chil-
dren is influenced by their own genotypes. Similarly, the child’s
development is influenced by the aspects of the environment
he or she seeks out and the different responses the child’s char-
acteristics and behavior evoke from other people.
n The field of behavior genetics is concerned with the joint
influence of genetic and environmental factors on behavior.
Through the use of a variety of family-study designs, behavior
geneticists have discovered a wide range of behavior patterns
that “run in families.” Many behavior geneticists use herita-
bility estimates to statistically evaluate the relative contribu-
tions of heredity and environment to behavior.
Brain Development
n A burgeoning area of developmental research focuses on the
development of the brain—the most complex structure in
the known universe. Neurons are the basic units of the brain’s
informational system. These cells transmit information via
electrical signals. Impulses are transmitted from one neuron to
another at synapses.
n The most human part of the human brain is the cortex,
because it is involved in a wide variety of higher mental func-
tions. Different areas of the cortex are specialized for general
behavioral categories. The cortex is divided into two cerebral
hemispheres, each of which is specialized for certain modes of
processing, a phenomenon known as cerebral lateralization.
n Brain development involves several processes, beginning with
neurogenesis and differentiation of neurons. In synaptogen-
esis, an enormous profusion of connections among neurons is
generated, starting prenatally and continuing for the first few
years after birth. Through synaptic pruning, excess connections
among neurons are eliminated.
n Experience plays a crucial role in the strengthening or elimina-
tion of synapses and hence in the normal wiring of the brain.
The fine-tuning of the brain involves experience-expectant
processes, in which existing synapses are preserved as a func-
tion of stimulation that virtually every human encounters, and
experience-dependent processes, in which new connections are
formed as a function of learning.
n Plasticity refers to the fact that nurture is the partner of nature
in the normal development of the brain. This fact makes it
possible in certain circumstances for the brain to rewire itself
in response to damage. It also makes the developing brain vul-
nerable to the absence of stimulation at sensitive periods in
development.
n The ability of the brain to recover from injury depends on the
age of the child. Very early damage, during the time when
neurogenesis and synaptogenesis are occurring, can have espe-
cially devastating effects. Damage during the preschool years,
when synapse elimination is occurring, is less likely to have
permanent harmful effects.
The Body: Physical Growth and Development
n Humans undergo a particularly prolonged period of physical
growth, during which growth is uneven, proceeding more rap-
idly early in life and in adolescence. Secular trends have been
observed in increases in average height and weight.

C H A P T E R S u M M A R Y n 127
Key Terms
alleles, p. 92
association areas, p. 109
axons, p. 106
behavior genetics, p. 99
cell body, p. 106
cerebral cortex, p. 108
cerebral hemispheres, p. 109
cerebral lateralization, p. 109
chromosomes, p. 89
corpus callosum, p. 109
crossing over, p. 91
dendrites, p. 106
DNA (deoxyribonucleic acid), p. 89
dominant allele, p. 92
environment, p. 88
event-related potentials (ERPs), p. 110
experience-dependent plasticity, p. 116
experience-expectant plasticity, p. 115
failure to thrive (nonorganic), p. 120
frontal lobe, p. 109
genes, p. 89
genome, p. 88
genotype, p. 88
glial cells, p. 107
heritability, p. 102
heritable, p. 99
heterozygous, p. 92
homozygous, p. 92
lobes, p. 108
multifactorial, p. 102
mutation, p. 90
myelin sheath, p. 107
myelination, p. 112
neurogenesis, p. 109
neurons, p. 106
norm of reaction, p. 93
occipital lobe, p. 108
parietal lobe, p. 108
phenotype, p. 88
phenylketonuria (PKU), p. 93
plasticity, p. 114
polygenic inheritance, p. 93
recessive allele, p. 92
regulator genes, p. 91
secular trends, p. 120
sex chromosomes, p. 90
spines, p. 111
synapses, p. 107
synaptic pruning, p. 113
synaptogenesis, p. 112
temporal lobe, p. 108
n Food preferences begin with innate responses by newborns to
basic tastes, but additional preferences develop as a result of
experience. Problems with the regulation of eating are evident
in the United States, where an epidemic of obesity is clearly
related to both environmental and genetic factors.
n In much of the rest of the world, the dominant problem is
getting enough food, and nearly half of all the children in
the world suffer from undernutrition. Inadequate nutrition
is closely associated with poverty, and it leads to a variety of
behavioral and physical problems in virtually every aspect
of the child’s life. Prevention of undernutrition is needed
to allow millions of children to develop normal brains and
bodies.
Critical Thinking Questions
1. A major focus of this chapter was the interaction of nature
and nurture. Consider yourself and your family (regard-
less of whether you were raised by your biological parents).
Identify some aspect of who you are that illustrates each
of the five relations depicted in Figure 3.1 and answer
these questions: (a) How and when was your sex deter-
mined? (b) What are some alleles you are certain or
relatively confident you share with other members of
your family? (c) What might be an example of a gene–
environment interaction in your parents’ behavior toward
you? (d) What would be an example of your active selection
of your own environment that might have influenced your
subsequent development? (e) What aspects of your own
environment might have had epigenetic effects on your
gene expression?
2. “Fifty percent of a person’s IQ is due to heredity and fifty
percent to environment.” Discuss what is wrong with this
statement, describing both what heritability estimates mean
and what they do not mean.
3. Relate the developmental processes of synaptogenesis and
synapse elimination to the concepts of experience-expectant
and experience-dependent plasticity.
4. What aspects of brain development do researchers think may
be related to the traits and behaviors of adolescents?
5. Think back over your activities and observations of the past
day or so. What aspects of your environment may relate to
the epidemic of obesity described in this chapter?
6. Consider Figure 3.13, which addresses malnutrition and cog-
nitive development. Imagine an undernourished 6-year-old
child living in the United States. Go through the figure and
generate a specific example of something that might happen
to this child at each point in the diagram. Now do the same
for a 6-year-old living in a poor, war-torn country.

128
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F R E N C H S C H O O L (20th century), Learning the Alphabet of Baksheesh (colour litho)

129
Theories of Cognitive
Development
n Piaget’s Theory
View of Children’s Nature
Central Developmental Issues
The Sensorimotor Stage (Birth to Age 2 Years)
The Preoperational Stage (Ages 2 to 7)
The Concrete Operational Stage (Ages 7 to 12)
The Formal Operational Stage (Age 12 and Beyond)
Piaget’s Legacy
Box 4.1: Applications Educational Applications of
Piaget’s Theory
Review
n Information-Processing Theories
View of Children’s Nature
Central Developmental Issues
Box 4.2: Applications Educational Applications of
Information-Processing Theories
Review
n Sociocultural Theories
View of Children’s Nature
Central Developmental Issues
Box 4.3: Applications Educational Applications of
Sociocultural Theories
Review
n Dynamic-Systems Theories
View of Children’s Nature
Central Development Issues
Box 4.4: Applications Educational Applications of
Dynamic-Systems Theories
Review
n Chapter Summary
chapter 4:

130
A
7-month-old boy, sitting on his father’s lap, becomes intrigued with
the father’s glasses, grabs one side of the frame, and yanks it. The fa-
ther says, “Ow!” and his son lets go, but then reaches up and yanks the
frame again. The father readjusts the glasses, but his son again grasps
them and yanks. How, the father wonders, can he prevent his son from
continuing this annoying routine without causing him to start screaming? Fortu-
nately, the father, a developmental psychologist, soon realizes that Jean Piaget’s the-
ory of cognitive development suggests a simple solution: put the glasses behind his
back. According to Piaget’s theory, removing an object from a young infant’s sight
should lead the infant to act as if the object never existed. The strategy works per-
fectly; after the father puts the glasses behind his back, his son shows no further in-
terest in them and turns his attention elsewhere. The father silently thanks Piaget.
This experience, which one of us actually had, illustrates in a small way how un-
derstanding theories of child development can yield practical benefits. It also illus-
trates three broader advantages of knowing about such theories:
1. Developmental theories provide a framework for understanding important phenom-
ena. Theories help to reveal the significance of what we observe about children,
both in research studies and in everyday life. Someone who witnessed the glasses
incident but who did not know about Piaget’s theory might have found the expe-
rience amusing but insignificant. Seen in terms of Piaget’s theory, however, this
passing event exemplifies a general and profoundly important developmental phe-
nomenon: infants younger than 8 months react to the disappearance of an object
as though they do not understand that the object still exists. In this way, theories
of child development place particular experiences and observations in a
larger context and deepen our understanding of their meaning.
2. Developmental theories raise crucial questions about human nature.
Pia get’s theory about young infants’ reactions to disappearing objects was
based on his informal experiments with infants younger than 8 months.
Piaget would cover one of their favorite objects with a cloth or otherwise
put it out of sight and then wait to see whether the infants tried to re-
trieve the object. They rarely did, leading Piaget to conclude that before
the age of 8 months, infants do not realize that hidden objects still exist.
Other researchers have challenged this explanation. They argue that in-
fants younger than 8 months do in fact understand that hidden objects
continue to exist but lack the memory or problem-solving skills neces-
sary for using that understanding to retrieve hidden objects (Baillargeon,
1993). Despite these disagreements about how best to interpret young
infants’ failure to retrieve hidden objects, researchers agree that Piaget’s
theory raises a crucial question about human nature: Do infants realize
from the first days of life that objects continue to exist when out of sight,
or is this something that they learn later? More significant, do young in-
fants understand that people continue to exist when they cannot be seen?
Do they fear that Mom no longer exists when she disappears from sight?
3. Developmental theories lead to a better understanding of children. Theo-
ries also stimulate new research that may support the theories’ claims,
fail to support them, or require refinements of them, thereby improv-
ing our understanding of children. For example, Piaget’s ideas led
Themes
n Nature and Nurture
n The Active Child
n Continuity/Discontinuity
Mechanisms of Change
n The Sociocultural Context
n Research and Children’s
Welfare
The author whose son loved to grab his
glasses is not the only one who has encoun-
tered this problem. If the mom in this pic-
ture was lucky enough to have read this
textbook, she may have solved the problem
in the same way.
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T H E O R I E S O F C O G N I T I V E D E V E L O P M E N T n 131
Munakata and her colleagues (1997) to test whether 7-month-olds’ failure to reach
for hidden objects was due to their lacking the motivation or the reaching skill to
retrieve them. To find out, the researchers created a situation similar to Piaget’s
object-permanence experiment, except that they placed the object, an attractive toy,
under a transparent cover rather than under an opaque one. In this situation, in-
fants quickly removed the cover and regained the toy. This finding seemed to sup-
port Piaget’s original interpretation by showing that neither lack of motivation nor
lack of ability to reach for the toy explained the infants’ usual failure to retrieve it.
In contrast, an experiment conducted by Diamond (1985) indicated a need to
revise Piaget’s theory. Using an opaque covering, as Piaget did, Diamond varied the
amount of time between when the toy was hidden and when the infant was allowed
to reach for it. She found that even 6-month-olds could locate the toy if allowed
to reach immediately, that 7-month-olds could wait as long as 2 seconds and still
succeed, that 8-month-olds could wait as long as 4 seconds and still succeed, and
so on. Diamond’s finding indicated that memory for the location of hidden objects,
as well as the understanding that they continue to exist, is crucial to success on the
task. In sum, theories of child development are useful because they provide frame-
works for understanding important phenomena, raise fundamental questions about
human nature, and motivate new research that increases understanding of children.
Because child development is such a complex and varied subject, no single the-
ory accounts for all of it. The most informative current theories focus primarily
on either cognitive development or social development. Providing a good theo-
retical account of development in even one of these areas is an immense challenge,
because each of them spans a huge range of topics. Cognitive development includes
the growth of such diverse capabilities as perception, attention, language, problem
solving, reasoning, memory, conceptual understanding, and intelligence. Social de-
velopment includes the growth of equally diverse areas: emotions, personality, re-
lationships with peers and family members, self-understanding, aggression, and
moral behavior. Given this immense range of developmental domains, it is easy
to understand why no one theory has captured the entirety of child development.
Therefore, we present cognitive and social theories in separate chapters. We
consider theories of cognitive development in this chapter, just before the chapters
on specific areas of cognitive development, and consider theories of social develop-
ment in Chapter 9, just before the chapters on specific areas of social development.
This chapter examines four theoretical perspectives on cognitive develop-
ment that are particularly influential: the Piagetian perspective, the information-
processing perspective, the sociocultural perspective, and the dynamic-systems
perspective. We consider each perspective’s fundamental assump-
tions about children’s nature, the central developmental issues on
which the perspective focuses, and practical examples of the per-
spective’s usefulness for helping children learn.
These four theoretical perspectives are influential in large
part because they provide important insights into the basic de-
velopmental themes described in Chapter 1. Each perspective
addresses all the themes to some extent, but each emphasizes dif-
ferent ones. For example, Piaget’s theory focuses on continuity/
discontinuity and the active child, whereas information-processing
theories focus on mechanisms of change (Table 4.1). Together, the
four perspectives allow a broader appreciation of cognitive devel-
opment than any one of them does alone.
TABLE 4.1
Main Questions Addressed by Theories
of Cognitive Development
Theory Main Questions Addressed
Piagetian Nature–nurture, continuity/discontinuity,
the active child
Information-processing Nature–nurture, how change occurs
Sociocultural Nature–nurture, influence of the
sociocultural context, how change occurs
Dynamic-systems Nature–nurture, the active child, how
change occurs

132 n ChApTer 4 THEORIES OF COGNITIVE DEVELOPMENT
Piaget’s Theory
Jean Piaget’s studies of cognitive development are a testimony to how much one
person can contribute to a scientific field. Before his work began to appear in the
early 1920s, there was no recognizable field of cognitive development. Nearly a
century later, Piaget’s theory remains the best-known cognitive developmental the-
ory in a field replete with theories. What accounts for its longevity?
One reason is that Piaget’s observations and descriptions vividly convey the
texture of children’s thinking at different ages. Another reason is the exceptional
breadth of the theory. It extends from the first days of infancy through adoles-
cence and examines topics as diverse as conceptualization of time, space, distance,
and number; language use; memory; understanding of other people’s perspectives;
problem solving; and scientific reasoning. Even today, it remains the most encom-
passing theory of cognitive development. A third source of its longevity is that it
offers an intuitively plausible depiction of the interaction of nature and nurture in
cognitive development, as well as of the continuities and discontinuities that char-
acterize intellectual growth.
View of Children’s Nature
Piaget’s fundamental assumption about children was that they are mentally ac-
tive as well as physically active from the moment of birth, and that their activity
greatly contributes to their own development. His approach to understanding
cognitive development is often labeled constructivist, because it depicts children
as constructing knowledge for themselves in response to their experiences. Three
of the most important of children’s constructive processes, according to Piaget,
are generating hypotheses, performing experiments, and drawing conclusions
from their observations. If this description reminds you of scientific problem
solving, you are not alone: the “child as scientist” is the dominant metaphor in
Piaget’s theory. Consider this description of his infant son:
Laurent is lying on his back. . . . He grasps in succession a celluloid swan, a box, etc.,
stretches out his arm and lets them fall. He distinctly varies the position of the fall.
When the object falls in a new position (for example, on his pillow), he lets it fall two
or three more times on the same place, as though to study the spatial relation.
(Piaget, 1952b, pp. 268–269)
In simple activities such as Laurent’s game of “drop the toy
from different places and see what happens,” Piaget per-
ceived the beginning of scientific experimentation.
This example also illustrates a second basic Piagetian as-
sumption: children learn many important lessons on their
own, rather than depending on instruction from adults or
older children. To further illuminate this point, Piaget cited
a friend’s recollection from childhood:
He was seated on the ground in his garden and he was count-
ing pebbles. Now to count these pebbles he put them in a row
and he counted them one, two, three up to 10. Then he fin-
ished counting them and started to count them in the other
direction. He began by the end and once again he found that
he had 10. He found this marvelous. . . . So he put them in a
circle and counted them that way and found 10 once again.
(Piaget, 1964, p. 12)
Jean piaget, whose work has had a profound
influence on developmental psychology, is
seen here interviewing a child to learn about
his thinking.
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P I A G E T ’ S T H E O R Y n 133
This incident also highlights a third basic assumption of Piaget’s: children are
intrinsically motivated to learn and do not need rewards from other people to do
so. When they acquire a new capability, they apply it as often as possible. They also
reflect on the lessons of their experience, because they want to understand them-
selves and everything around them.
Central Developmental Issues
In addition to his view that children actively shape their own development, Piaget
offered important insights regarding the roles of nature and nurture and of conti-
nuities and discontinuities in development.
Nature and Nurture
Piaget believed that nature and nurture interact to produce cognitive development.
In his view, nurture includes not just the nurturing provided by parents and other
caregivers but every experience children encounter. Nature includes children’s ma-
turing brain and body; their ability to perceive, act, and learn from experience; and
their tendency to integrate particular observations into coherent knowledge. As this
description suggests, a vital part of children’s nature is to respond to their nurture.
Sources of Continuity
Piaget depicted development as involving both continuities and discontinuities.
The main sources of continuity are three processes—assimilation, accommodation,
and equilibration—that work together from birth to propel development forward.
Assimilation is the process by which people incorporate incoming information
into concepts they already understand. To illustrate, when one of our children was
2 years old, he saw a man who was bald on top of his head and had long frizzy hair
on the sides. To his father’s great embarrassment, the toddler gleefully shouted,
“Clown! Clown!” (Actually, it sounded more like “Kown! Kown!”) The man appar-
ently looked enough like a “kown” that the boy could assimilate him to his clown
concept.
Accommodation is the process by which people improve their current under-
standing in response to new experiences. In the “kown” incident, the boy’s father
explained to his son that the man was not a clown and that even though his hair
looked like a clown’s, he was not wearing a funny costume and was not doing silly
things to make people laugh. With this new information, the boy was able to ac-
commodate his clown concept to the standard one, allowing other men with bald
pates and long side hair to pass by in peace.
Equilibration is the process by which children (indeed, people of all ages) bal-
ance assimilation and accommodation to create stable understanding. Equilibra-
tion includes three phases. First, children are satisfied with their understanding
of a particular phenomenon; Piaget labeled this a state of equilibrium, because the
children do not see any discrepancies between their observations and their under-
standing of the phenomenon. Then, new information leads them to perceive that
their understanding is inadequate. Piaget said that this realization puts children in
a state of disequilibrium; they recognize shortcomings in their understanding of the
phenomenon, but they cannot generate a superior alternative. Finally, they develop
a more sophisticated understanding that eliminates the shortcomings of the old
one, creating a more advanced equilibrium within which a broader range of obser-
vations can be understood.
perhaps toddlers yelling “Kown, kown!” set
Larry, a member of The Three Stooges, on
his career path.
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assimilation n the process by which
people translate incoming information
into a form that fits concepts they already
understand
accommodation n the process by which
people adapt current knowledge struc-
tures in response to new experiences
equilibration n the process by which
children (or other people) balance assimi-
lation and accommodation to create
stable understanding

134 n ChApTer 4 THEORIES OF COGNITIVE DEVELOPMENT
One example of how equilibration works involves the belief—held by most 4- to
7-year-olds in a wide range of cultures (Inagaki & Hatano, 2008)—that animals are
the only living things. This belief seems to stem from the assumption that only ani-
mals can move in ways that help them survive. Sooner or later, children realize that
plants also move in ways that promote their survival (e.g., toward sunlight). This
new information is difficult for them to assimilate to their prior thinking. The re-
sulting disparity between their previous understanding of living things and their new
knowledge about plants creates a state of disequilibrium, in which they are unsure of
what it means to be alive. Later, their thinking accommodates to the new informa-
tion about plants. That is, they realize that both animals and plants move in adaptive
ways and that, because adaptive movement is a key characteristic of living things,
plants as well as animals must be alive (Opfer & Gelman, 2001; Opfer & Siegler,
2004). This realization constitutes a more stable equilibrium, because subsequent
information about plants and animals will not contradict it. Through innumerable
such equilibrations, children acquire knowledge of the world around them.
Sources of Discontinuity
Although Piaget placed some emphasis on continuous aspects of cognitive devel-
opment, the most famous part of his theory concerns discontinuous aspects, which
he depicted as distinct stages of cognitive development. Piaget viewed these stages
as products of the basic human tendency to organize knowledge into coherent
structures. Each stage represents a coherent way of understanding one’s experience,
and each transition between stages represents a discontinuous intellectual leap from
one coherent way of understanding the world to the next, higher one. The follow-
ing are the central properties of Piaget’s stage theory:
1. Qualitative change. Piaget believed that children of different ages think in quali-
tatively different ways. For example, he proposed that children in the early stages
of cognitive development conceive of morality in terms of the consequences of a per-
son’s behavior, whereas children in later stages conceive of it in terms of the person’s
intent. Thus, a 5-year-old would judge someone who accidentally broke a whole jar
of cookies as having been naughtier than someone who deliberately stole a single
cookie; an 8-year-old would reach the opposite conclusion. This difference rep-
resents a qualitative change, because the two children are basing their moral judg-
ments on entirely different criteria.
2. Broad applicability. The type of thinking characteristic of each stage influences
children’s thinking across diverse topics and contexts.
3. Brief transitions. Before entering a new stage, children pass through a brief tran-
sitional period in which they fluctuate between the type of thinking characteristic
of the new, more advanced stage and the type of thinking characteristic of the old,
less advanced one.
4. Invariant sequence. Everyone progresses through the stages in the same order
without skipping any of them.
Piaget hypothesized four stages of cognitive development: the sensorimotor stage,
the preoperational stage, the concrete operational stage, and the formal operational
stage. In each stage, children exhibit new abilities that allow them to understand
the world in qualitatively different ways than they had previously.

P I A G E T ’ S T H E O R Y n 135
1. In the sensorimotor stage (birth to age 2 years), infants’ intelligence is
expressed through their sensory and motor abilities, which they use to per-
ceive and explore the world around them. These abilities allow them to learn
about objects and people and to construct rudimentary forms of fundamental
concepts such as time, space, and causality. Throughout the sensorimotor
period, infants live largely in the here and now: their intelligence is bound to
their immediate perceptions and actions.
2. In the preoperational stage (ages 2 to 7 years), toddlers and preschoolers
become able to represent their experiences in language and mental imagery.
This allows them to remember the experiences for longer periods and to
form more sophisticated concepts. However, as suggested by the term pre-
operational, Piaget’s theory emphasizes young children’s inability to perform
certain mental operations, such as considering multiple dimensions simultane-
ously. This leads to children’s being unable to form certain ideas, such as the
idea that pouring all the water from a short, wide glass into a taller, narrower
glass does not change the total amount of water, even though the column of
water is higher in the second glass. In other words, they do not recognize that
the increased height of the liquid column in the second glass is compensated
for by its narrower width.
3. In the concrete operational stage (ages 7 to 12 years), children can reason
logically about concrete objects and events; for example, they understand
that pouring water from one glass to a taller, narrower one leaves the amount
of water unchanged. However, concrete operational reasoners cannot think
in purely abstract terms or generate systematic scientific experiments to test
their beliefs.
4. In the final stage of cognitive development, the formal operational stage
(age 12 years and beyond), children can think deeply not only about concrete
events but also about abstractions and purely hypothetical situations. They
also can perform systematic scientific experiments and draw appropriate con-
clusions from them, even when the conclusions differ from their prior beliefs.
With this overview of Piaget’s theory, we can consider in greater depth major
changes that take place in each stage.
The Sensorimotor Stage (Birth to Age 2 Years)
One of Piaget’s most profound insights was his realization that the roots of adult
intelligence are present in infants’ earliest behaviors, such as their seemingly aim-
less sucking, flailing, and grasping. He recognized that these behaviors are not
random but instead reflect an early type of intelligence involving sensory and
motor activity. Indeed, many of the clearest examples of the active child theme
come from Piaget’s descriptions of the development of what he called “sensorimo-
tor intelligence.”
Over the course of the first 2 years, infants’ sensorimotor intelligence develops
tremendously. The sheer amount of change may at first seem astonishing. However,
when we consider the immense variety of new experiences that infants encounter
during this period, and the tripling of brain weight between birth and age 3 (with
weight being an index of brain development during this period), the huge increase
in infants’ cognitive abilities is more understandable. The profound developments
that Piaget described as occurring during infancy call attention to a general prin-
ciple: children’s thinking grows especially rapidly in the first few years.
sensorimotor stage n the period (birth
to 2 years) within Piaget’s theory in which
intelligence is expressed through sensory
and motor abilities
preoperational stage n the period
(2 to 7 years) within Piaget’s theory in
which children become able to represent
their experiences in language, mental
imagery, and symbolic thought
concrete operational stage n the
period (7 to 12 years) within Piaget’s
theory in which children become able to
reason logically about concrete objects
and events
formal operational stage n the period
(12 years and beyond) within Piaget’s
theory in which people become able to
think about abstractions and hypothetical
situations

136 n ChApTer 4 THEORIES OF COGNITIVE DEVELOPMENT
Infants are born with many reflexes. When objects move in front of their eyes,
they visually track them; when objects are placed in their mouths, they suck them;
when objects come into contact with their hands, they grasp them; when they hear
noises, they turn toward them; and so on. Piaget believed that these simple reflexes
and perceptual abilities are the foundation of intelligence.
Even during their first month, infants begin to modify their reflexes to make
them more adaptive. At birth, for example, they suck in a similar way regardless of
what they are sucking. Within a few weeks, however, they adjust their sucking ac-
cording to the object in their mouth. Thus, they suck on a milk-yielding nipple in a
way that enhances the efficiency of their feeding and that is different from the way
they suck on a finger or even a pacifier. As this example illustrates, from the first days
out of the womb, infants accommodate their actions to the parts of the environment
with which they interact.
Over the course of the first few months, infants begin to organize separate re-
flexes into larger behaviors, most of which are centered on their own bodies. For
example, instead of being limited to exercising their grasping and sucking reflexes
separately, they can integrate them: when an object touches their palm, they can
grasp it, bring it to their mouth, and suck on it. Thus, their reflexes serve as build-
ing blocks for more complex behaviors.
In the middle of their first year, infants become increasingly interested in the
world around them—people, animals, toys, and other objects and events beyond
their own bodies. A hallmark of this shift is their repetition of actions on the en-
vironment that produce pleasurable or interesting results. Repeatedly banging a
rattle and squeezing a rubber duck again and again to make it squeak are examples
of favorite activities for many infants at this time.
Piaget (1954) made a striking and controversial claim about a deficiency in in-
fants’ thinking during this period—the one referred to in the chapter-opening an-
ecdote about the father hiding his glasses. The claim was that through the age of
8 months, infants lack object permanence, the knowledge that objects continue
to exist even when they are out of view. This claim was based largely on Piaget’s
observations of his own children, Laurent, Lucienne, and Jacqueline. The follow-
ing account of an experiment with Laurent reflects the type of observation that in-
spired Piaget’s belief about object permanence:
At age 7 months, 28 days, I offer him a little bell behind a cushion. So long as he sees
the little bell, however small it may be, he tries to grasp it. But if the little bell disap-
pears completely he stops all searching. I then resume the experiment using my hand
as a screen. Laurent’s arm is outstretched and about to grasp the little bell at the mo-
ment I make it disappear behind my hand which is open and at a distance of about 15
cm from him. He immediately withdraws his arm, as though the little bell no longer
existed.
(Piaget, 1954, p. 39)
Thus, in Piaget’s view, for infants younger than 8 months, the adage “out of
sight, out of mind” is literally true. They are able to mentally represent (think
about) only the objects that they can perceive at the moment.
By the end of the first year, infants search for hidden objects, thus indicating that
they mentally represent the objects’ continuing existence even when they no longer
see them. These initial representations of objects are fragile, however, as reflected
in the A-not-B error. In this error, once 8- to 12-month-olds have reached for and
found a hidden object several times in one place (location A), when they see the
object hidden at a different place (location B) and are prevented from immediately
searching for it, they tend to reach where they initially found the object (location
piaget proposed that when infants suck on
objects, they gain not only pleasure but also
knowledge about the world beyond their
bodies.
R
O
B
E
R
T
S
IE
G
LE
R
object permanence n the knowledge
that objects continue to exist even when
they are out of view
A-not-B error n the tendency to reach
for a hidden object where it was last
found rather than in the new location
where it was last hidden
deferred imitation n the repetition of
other people’s behavior a substantial time
after it originally occurred

P I A G E T ’ S T H E O R Y n 137
A) (see Figure 4.1). Not until around their first birthday do infants consistently
search first at the object’s current location.
At around 1 year of age, infants begin to actively and avidly explore the po-
tential ways in which objects can be used. The “child as scientist” example pre-
sented earlier, in which Piaget’s son Laurent varied the positions from which he
dropped different objects to see what would happen, provides one instance of this
emerging competency. Similar examples occur in every family with an infant. Few
parents forget their 12- to 18-month-old sitting in a high chair, banging various
objects against the chair’s tray—first a spoon, then a plate, then a cup— seemingly
fascinated by the sounds made by the different objects. Nor do they forget their
infant dropping bathroom articles into the toilet, or pouring a bag of flour on
the kitchen floor, just to see what happens. Piaget regarded such actions as the
beginnings of scientific experimentation (many parents see such behaviors in less
positive terms).
In the last half-year of the sensorimotor stage (ages 18 to 24 months), accord-
ing to Piaget, infants become able to form enduring mental representations. The
first sign of this new capability is deferred imitation, that is, the repetition of other
people’s behavior minutes, hours, or even days after it occurred. Consider Piaget’s
observation of 1-year-old Jacqueline:
Jacqueline had a visit from a little boy . . . who, in the course of the afternoon, got
into a terrible temper. He screamed as he tried to get out of a playpen and pushed it
backward, stamping his feet. . . . The next day, she herself screamed in her playpen and
tried to move it, stamping her foot lightly several times in succession.
(Piaget, 1951, p. 63)
Piaget indicated that Jacqueline had never before thrown such a tantrum. Pre-
sumably, she had watched and remembered her playmate’s behavior, maintained a
representation of it overnight, and imitated it the next day.
FIGURE 4.1 piaget’s A-not-B task A
child looks for and finds a toy under the
cloth where it was hidden (left frame). After
several such experiences, the toy is hidden
in a different location (right frame). The
child continues to look where he found the
toy previously, rather than where it is hidden
now. The child’s ignoring the visible protru-
sion of the toy under the cloth in the right
frame illustrates the strength of the inclina-
tion to look in the previous hiding place.
B
O
T
H
:
B
E
N
C
LO
R
E
This toddler’s techniques for applying eye
makeup may not exactly mirror those he
has seen his mother use, but they are close
enough to provide a compelling illustration
of deferred imitation, a skill that children
gain during their second year.
C
O
U
R
T
E
S
Y
O
F
J
U
D
Y
D
E
LO
A
C
H
E

138 n ChApTer 4 THEORIES OF COGNITIVE DEVELOPMENT
When we consider Piaget’s account of cognitive development during infancy,
several notable trends are evident.
n At first, infants’ activities center on their own bodies; later, their activities
include the world around them.
n Early goals are concrete (shaking a rattle and listening to the sound it makes);
later goals often are more abstract (varying the heights from which objects are
dropped and observing how the effects vary).
n Infants become increasingly able to form mental representations, moving from
“out of sight, out of mind” to remembering a playmate’s actions from a full day
earlier. Such enduring mental representations make possible the next stage,
which Piaget called preoperational thinking.
The Preoperational Stage (Ages 2 to 7)
Piaget viewed the preoperational period as including a mix of striking cognitive
acquisitions and fascinating limitations. Perhaps the foremost acquisition is the
development of symbolic representations; among the most notable weaknesses are
egocentrism and centration.
Development of Symbolic Representations
Have you ever seen preschoolers use two Popsicle sticks to represent a gun or a
playing card to represent an iPhone? Forming such personal symbols is common
among 3- to 5-year-olds. It is one of the ways in which they exercise their emerging
capacity for symbolic representation—the use of one object to stand for another.
Typically, these personal symbols physically resemble the objects they represent.
The Popsicle sticks’ and playing card’s shapes somewhat resemble those of a gun
and iPhone.
As children develop, they rely less on self-generated symbols and more on con-
ventional ones. For example, when 5-year-olds play games involving pirates, they
might wear a patch over one eye and a bandanna over their head because that is the
way pirates are commonly depicted. Heightened symbolic capabilities during the
preoperational period are also evident in the growth of drawing. Children’s draw-
ings between ages 3 and 5 make increasing use of symbolic conventions, such as
representing the leaves of flowers as Vs (Figure 4.2).
Egocentrism
Although Piaget noted important growth in children’s thinking during the pre-
operational stage, he found the limitations of this period to be as intriguing and
revealing of preoperational understanding. As noted, one important limitation is
egocentrism, that is, perceiving the world solely from one’s own point of view. An
example of this limitation involves preschoolers’ difficulty in taking other people’s
spatial perspectives. Piaget and Inhelder (1956/1977) demonstrated this difficulty
by having 4-year-olds sit at a table in front of a model of three mountains of dif-
ferent sizes (Figure 4.3). The children were asked to identify which of several
photographs depicted what a doll would see if it were sitting on chairs at various
locations around the table. Solving this problem required children to recognize
that their own perspective was not the only one possible and to imagine what the
view would be from another location. Most 4-year-olds, according to Piaget, can-
not do this.
FIGURE 4.3 piaget’s three-mountains
task When asked to choose the picture that
shows what the doll sitting in the seat across
the table would see, most children younger
than 6 years choose the picture showing
how the scene looks to them, illustrating
their difficulty in separating their own per-
spective from that of others.
FIGURE 4.2 A 4-year-old’s drawing of a
summer day Note the use of simple artistic
conventions, such as the V-shaped leaves on
the flowers.
IL
LU
S
T
R
AT
IO
N
B
Y
V
IV
IA
N
H
O
X
S
E
Y
symbolic representation n the use of
one object to stand for another
egocentrism n the tendency to perceive
the world solely from one’s own point of
view

P I A G E T ’ S T H E O R Y n 139
The same difficulty in taking other people’s perspectives is seen in quite different
contexts—for example, in communication. As illustrated in Figure 4.4, preschoolers
often talk right past each other, focused only on what they themselves are saying and
seemingly oblivious to their partner’s comments. Preschoolers’ egocentric communi-
cation also is evident when they make statements that require knowledge that they
themselves possess but that their listeners couldn’t be expected to have. For example,
2- and 3-year-olds frequently tell day-care providers and parents things like “He
took it from me,” in situations where the person or object to which the child is re-
ferring is totally unclear. Egocentric thinking is also evident in preschoolers’ expla-
nations of events and behavior. Consider the following interviews with preschoolers
that occurred in the original version of the TV show Kids Say the Darndest Things:
Interviewer: Any brothers or sisters?
Child: I have a brother a week old.
I: What can he do?
C: He can say “Mamma” and “Daddy.”
I: Can he walk?
C: No, he’s too lazy.
Interviewer: Any brothers or sisters?
Child: A 2-months-old brother.
I: How does he behave?
C: He cries all night.
I: Why is that, do you think?
C: He probably thinks he’s missing something on television.
(Linkletter, 1957, p. 6)
Over the course of the preoperational period, egocentric speech becomes less
common. An early sign of progress is children’s verbal quarrels, which become in-
creasingly frequent during this period. The fact that a child’s statements elicit a
playmate’s objection indicates that the playmate is at least paying attention to the
differing perspective that the other child’s comment implies. Children also become
better able to envision spatial perspectives other than their own during the pre-
operational period. We all remain somewhat egocentric throughout our lives, but
most of us do improve.
Centration
A related limitation of preschoolers’ thinking is centration, that is, focusing on a
single, perceptually striking feature of an object or event to the exclusion of other
relevant but less striking features. Children’s approaches to balance-scale prob-
lems provide a good example of centration. If presented with a balance scale like
that in Figure 4.5 and asked which side will go down, 5- and 6-year-olds center
on the amount of weight on each side, ignore the distance of the weights from the
fulcrum, and say that whichever side has more weight will go down (Inhelder &
Piaget, 1958).
Another good example of centration comes from Piaget’s research on chil-
dren’s understanding of conservation. The idea of the conservation concept is that
merely changing the appearance or arrangement of objects does not necessarily
change other key properties, such as quantity of material. Three variants of the con-
cept that are commonly studied in 5- to 8-year-olds are conservation of liquid quan-
tity, conservation of solid quantity, and conservation of number (Piaget, 1952a). In
all three cases, the tasks used to measure children’s understanding employ a three-
phase procedure (Figure 4.6). First, as in the figure, children are shown two objects
My dad is a policeman…
I have a real big dog…
He licks my face all the time…
He caught a robber once…
FIGURE 4.4 egocentrism An example
of young children’s egocentric conversations.
FIGURE 4.5 The balance scale When
asked to predict which side of a balance
scale, like the one shown above, would go
down if the arm were allowed to move, 5-
and 6-year-olds almost always center their
attention on the amount of weight and
ignore the distances of the weights from the
fulcrum. Thus, they would predict that the
left side would go down, although it is the
right side that would actually drop.
centration n the tendency to focus on a
single, perceptually striking feature of an
object or event
conservation concept n the idea
that merely changing the appearance of
objects does not necessarily change other
key properties

140 n ChApTer 4 THEORIES OF COGNITIVE DEVELOPMENT
(e.g., two glasses of orangeade, two clay sausages) that are identical in quantity, or
two sets of objects (e.g., two rows of pennies) that are identical in number. Once
children agree that the dimension of interest (e.g., the amount of orangeade or the
number of pennies) is equal in both items, they observe a second phase in which the
experimenter transforms one object or set of objects in a way that makes it look dif-
ferent but does not change the dimension of interest. Orangeade might be poured
into a taller, narrower, glass; a short, thick clay sausage might be molded into a long,
thin sausage; or one of the two rows of pennies might be spread out. Finally, in the
third phase, children are asked whether the dimension of interest, which they ear-
lier had said was equal for the two objects or sets of objects, is still equal.
The large majority of 4- and 5-year-olds answer “no.” On conservation-
of- liquid-quantity problems, they claim that the taller, narrower glass has more
orangeade; on conservation-of-solid-quantity problems, they claim that the long,
thin sausage has more clay than the short, thick one; and so on. Children of this
age make similar errors in everyday contexts; for example, they often think that if a
child has one fewer cookie than another child, a fair solution is to break one of the
short-changed child’s cookies into two pieces (Miller, 1984).
A variety of weaknesses that Piaget perceived in preoperational thinking con-
tribute to these difficulties with conservation problems. Preoperational thinkers
center their attention on the single, perceptually salient dimension of height or
length, ignoring other relevant dimensions. In addition, their egocentrism leads to
their failing to understand that their own perspective can be misleading—that just
because a tall narrow glass of orangeade or a long thin clay sausage looks as though
“Now watch what I do”
(stretching one piece of clay).
“Now watch what I do”
(pouring contents of one glass).
“Now, do they have the same amount
of clay or a different amount?”
“Do they have the same amount
of clay or a different amount?”
CONSERVATION
OF
LIQUID QUANTITY
CONSERVATION
OF
SOLID QUANTITY
“Now watch what I do”
(spreading one row).
“Is there the same number
or a different number?”
CONSERVATION
OF
NUMBER
PHASE 1 PHASE 2 PHASE 3
“Do they have the same amount
of orange drink or a different
amount?”
“Now, do they have the same amount
of orange drink or a different
amount?”
“Now, is there the same number
or a different number?”
FIGURE 4.6 procedures used to test
conservation of liquid quantity, solid
quantity, and number Most 4- and 5-year-
olds say that the taller liquid column has
more liquid, the longer sausage has more
clay, and the longer row has more objects.

P I A G E T ’ S T H E O R Y n 141
it has more orangeade or clay than a shorter, wider one does not mean that it re-
ally does. Children’s tendency to focus on static states of objects (the appearance
of the objects after the transformation) and to ignore the transformation that was
performed (pouring the orangeade or reshaping the clay) also contributes to their
difficulty in solving conservation problems.
In the next period of cognitive development, the concrete operational stage, chil-
dren largely overcome these and other related limitations.
The Concrete Operational Stage (Ages 7 to 12)
At around age 7, according to Piaget, children begin to reason logically about con-
crete features of the world. Development of the conservation concept exemplifies
this progress. Although few 5-year-olds solve any of the three conservation tasks de-
scribed in the previous section, most 7-year-olds solve all of them. The same progress
in thinking also allows children in the concrete operational stage to solve many other
problems that require attention to multiple dimensions. For example, on the balance-
scale problem, they consider distance from the fulcrum as well as weight of objects.
However, this relatively advanced reasoning is, according to Piaget, limited to
concrete situations. Thinking systematically remains very difficult, as does rea-
soning about hypothetical situations. These limitations are evident in the types
of experiments that concrete operational children perform to solve the pendulum
problem (Inhelder & Piaget, 1958) (Figure 4.7). In this problem, children are pre-
sented a pendulum frame, a set of strings of varying length with a loop at each end,
and a set of metal weights of varying weight, any of which can be attached to any
string. When the loop at one end of the string is attached to a weight, and the loop
at the other end is attached to the frame of the pendulum, the string can be swung.
The task is to perform experiments that indicate which factor or factors influence
the amount of time it takes the pendulum to swing through a complete arc. Is it the
length of the string, the heaviness of the weight, the height from which the weight
is dropped, or some combination of these factors? Think for a minute: How would
you go about solving this problem?
Most concrete operational children begin their experiments believing that the
relative heaviness of the weights being dropped is the most important factor, perhaps
the only important one. This belief is not unreasonable; indeed, most adolescents
and adults share it. What distinguishes the children’s reasoning from that of older
individuals is how they test their belief. Concrete operational reasoners design biased
experiments from which no valid conclusion can be drawn. For example, they might
compare the travel time of a heavy weight on a short string dropped from a high po-
sition to the travel time of a light weight on a long string dropped from a lower posi-
tion. When the first string goes faster, they conclude that, just as they thought, heavy
weights go faster. This premature conclusion, however, reflects their limited ability
to think systematically or to imagine all possible combinations of variables. They
fail to imagine that the faster motion might be related to the length of the string or
the height from which the string was dropped, rather than the weight of the object.
The Formal Operational Stage (Age 12 and Beyond)
Formal operational thinking, which includes the ability to think abstractly and to rea-
son hypothetically, is the pinnacle of the Piagetian stage progression. The difference
between reasoning in this stage and in the previous one is clearly illustrated by for-
mal operational reasoners’ approach to the pendulum problem. Framing the problem
FIGURE 4.7 Inhelder and piaget’s pen-
dulum problem The task is to compare the
motions of longer and shorter strings, with
lighter and heavier weights attached, in
order to determine the influence of weight,
string length, and dropping point on the
time it takes for the pendulum to swing back
and forth. Children younger than 12 usually
perform unsystematic experiments and draw
incorrect conclusions.

142 n ChApTer 4 THEORIES OF COGNITIVE DEVELOPMENT
more abstractly than do children in the concrete operational stage, they see that any
of the variables—weight, string length, and dropping point—might influence the
time it takes for the pendulum to swing through an arc, and that it is therefore neces-
sary to test the effect of each variable systematically. To test the effect of weight, they
compare times to complete an arc for a heavier weight and a lighter weight, attached
to strings of equal length and dropped from the same height. To test the effect of
string length, they compare the travel times of a long and a short string, with equal
weight dropped from the same position. To test the influence of dropping point, they
vary the dropping point of a given weight attached to a given string. Such a
systematic set of experiments allows the formal operational thinker to de-
termine that the only factor that influences the pendulum’s travel time is the
length of the string; neither weight nor dropping point matters.
Piaget believed that unlike the previous three stages, the formal opera-
tional stage is not universal: not all adolescents (or adults) reach it. For those
adolescents who do reach it, however, formal operational thinking greatly
expands and enriches their intellectual universe. Such thinking makes it
possible for them to see the particular reality in which they live as only one
of an infinite number of possible realities. This insight leads them to think
about alternative ways that the world could be and to ponder deep questions
concerning truth, justice, and morality. It no doubt also helps account for
the fact that many people first acquire a taste for science fiction during ado-
lescence. The alternative worlds depicted in science-fiction stories appeal to
adolescents’ emerging capacity to think about the world they know as just
one of many possibilities and to wonder whether a better world is possible.
The attainment of formal operational thinking does not mean that ad-
olescents will always reason in advanced ways, but it does, according to
Piaget, mark the point at which adolescents attain the reasoning powers of
intelligent adults. (Some ways in which Piaget’s theory can be applied to improving
education are discussed in Box 4.1.)
Piaget’s Legacy
Although much of Piaget’s theory was formulated many years ago, it remains a very
influential approach to understanding cognitive development. Some of its strengths
were mentioned earlier. It provides a good overview of children’s thinking at dif-
ferent points in development (Table 4.2). It includes countless fascinating observa-
tions. It offers a plausible and appealing perspective on children’s nature. It surveys
a remarkably broad spectrum of developments and covers the entire age span from
infancy through adolescence.
However, subsequent analyses (Flavell, 1971, 1982; Miller, 2011) have identi-
fied some crucial weaknesses in Piaget’s theory. The following four are particularly
important:
1. The stage model depicts children’s thinking as being more consistent than it is. Accord-
ing to Piaget, once children enter a given stage, their thinking consistently shows
the characteristics of that stage across diverse concepts. Subsequent research, how-
ever, has shown that children’s thinking is far more variable than this depiction sug-
gests. For example, most children succeed on conservation-of-number problems by
age 6, whereas most do not succeed on conservation-of-solid-quantity problems
until age 8 or 9 (Field, 1987). Piaget recognized that such variability exists but un-
derestimated its extent and failed to explain it.
Teenagers’ emerging ability to understand
that their reality is only one of many pos-
sible realities may cause teens to develop a
taste for science fiction.
M
A
R
K
R
IC
H
A
R
D
S
/
P
H
O
T
O
E
D
IT

P I A G E T ’ S T H E O R Y n 143
BOX 4.1: applications
EDUCATIONAL APPLICATIONS OF PIAGET’S THEORY
Piaget’s view of children’s cognitive devel-
opment holds a number of general implica-
tions for how children should be educated
(Case, 1998; Piaget, 1972). Most gener-
ally, it suggests that children’s distinctive
ways of thinking at different ages need to be
considered in deciding how to teach them.
For example, children in the concrete op-
erational stage would not be expected to be
ready to learn purely abstract concepts such
as inertia and equilibrium state, whereas
adolescents in the formal operational stage
would be. Taking into account such general
age-related differences in cognitive level
before deciding when to teach particular
concepts is often labeled a “child-centered
approach.”
A second implication of Piaget’s approach
is that children learn best by interacting with
the environment, both mentally and physi-
cally. One research demonstration of this
principle involved promoting children’s un-
derstanding of the concept of speed (Levin,
Siegler, & Druyan, 1990). The investigation
focused on problems of a type beloved by
physics teachers: “When a race horse travels
around a circular track, do its right and left
sides move at the same speed?” It appears
obvious that they do, but, in fact, they do
not. The side toward the outside of the track
is covering a slightly greater distance in the
same amount of time as the side toward the
inside and therefore is moving slightly faster.
Levin and her colleagues devised a proce-
dure that allowed children to actively expe-
rience how different parts of a single object
can move at different speeds. They attached
one end of a 7-foot-long metal bar to a pivot
that was mounted on the floor. One by one,
6th-graders and an experimenter took four
walks around the pivot while holding onto the
bar. On two of the walks, the child held the
bar near the pivot and the experimenter held
it at the far end; on the other two walks, they
switched positions (see figure). After each
walk, children were asked whether the inner
or outer part of the bar had moved faster.
The differences in the speeds required
for walking while holding the inner and the
outer parts of the metal bar were so dra-
matic that the children generalized their
new understanding to other problems in-
volving circular motion, such as cars moving
around circular tracks on a computer screen.
In other words, physically experiencing the
concept accomplished what years of formal
science instruction usually fail to do. As
one boy said to the experimenter, “Before,
I hadn’t experienced it. I didn’t think about
it. Now that I have had that experience, I
know that when I was on the outer circle, I
had to walk faster to be at the same place as
you” (Levin et al., 1990). Clearly, relevant
physical activities, accompanied by ques-
tions that call attention to the lessons of the
activities, can foster children’s learning.
The child and adult are holding onto a bar as
they walk around a circle four times. On the
first two trips around, the child holds the bar
near the pivot; on the second two, the child
holds it at its end. The much faster pace
needed to keep up with the bar when holding
onto its end leads the child to realize that the
end was moving faster than the inner portion
(Levin et al., 1990).
TABLE 4.2
piaget’s Stages of Cognitive Development
Stage Approximate Age New Ways of Knowing
Sensorimotor Birth to 2 years Infants know the world through their senses and
through their actions. For example, they learn what
dogs look like and what petting them feels like.
Preoperational 2–7 years Toddlers and young children acquire the ability to
internally represent the world through language and
mental imagery. They also begin to be able to see the
world from other people’s perspectives, not just from
their own.
Concrete operational 7–12 years Children become able to think logically, not just
intuitively. They now can classify objects into precisely
defined categories and understand that events are often
influenced by multiple factors, not just one.
Formal operational 12 years and beyond Adolescents can think systematically and reason about
what might be, as well as what is. This allows them
to understand politics, ethics, and science fiction, as
well as to engage in scientific reasoning.

144 n ChApTer 4 THEORIES OF COGNITIVE DEVELOPMENT
2. Infants and young children are more cognitively competent than Piaget recognized.
Piaget employed fairly difficult tests to assess most of the concepts he studied. This
led him to miss infants’ and young children’s earliest knowledge of these concepts.
For example, Piaget’s test of object permanence required children to reach for the
hidden object after a delay; Piaget claimed that children do not do this until 8 or
9 months of age. However, alternative tests of object permanence, which analyze
where infants look immediately after the object has disappeared from view, indicate
that by 3 months of age, even these young infants at least suspect that objects con-
tinue to exist (Baillargeon, 1987; 1993).
3. Piaget’s theory understates the contribution of the social world to cognitive devel-
opment. Piaget’s theory focuses on how children come to understand the world
through their own efforts. From the day that children emerge from the womb,
however, they live in an environment of adults and older children who shape their
cognitive development in countless ways. A child’s cognitive development reflects
the contributions of other people, as well as of the broader culture, to a far greater
degree than Piaget’s theory acknowledges.
4. Piaget’s theory is vague about the cognitive processes that give rise to children’s thinking
and about the mechanisms that produce cognitive growth. Piaget’s theory provides any
number of excellent descriptions of children’s thinking. It is less revealing, however,
about the processes that lead children to think in a particular way and that produce
changes in their thinking. Assimilation, accommodation, and equilibration have an
air of plausibility, but how they operate is unclear.
These weaknesses of Piaget’s theory do not negate the magnitude of his achieve-
ment: it remains one of the major intellectual accomplishments of the past century.
However, appreciating the weaknesses as well as the strengths of his theory is nec-
essary for understanding why alternative theories of cognitive development have
become increasingly prominent.
In the remainder of this chapter, we consider the three most prominent alterna-
tive theories: information-processing, sociocultural, and dynamic-systems. Each type
of theory can be seen as an attempt to overcome a major weakness of Piaget’s ap-
proach. Information-processing theories emphasize precise characterizations of
the processes that give rise to children’s thinking and the mechanisms that produce
cognitive growth. Sociocultural theories emphasize the ways in which children’s
interactions with the social world, both with other people and with the products of
their culture, guide cognitive development. Dynamic-systems theories emphasize
infants’ and young children’s developing physical and mental capabilities and how
these capabilities are attained.
review:
Piaget’s theory of cognitive development emphasizes the interaction of nature and nurture,
continuities and discontinuities, and children’s active contribution to their own development.
The continuities of development are produced by assimilation, accommodation, and equili-
bration. Assimilation involves interpreting incoming information to fit current understanding.
Accommodation involves adapting one’s thinking toward being more consistent with new ex-
periences. Equilibration involves balancing assimilation and accommodation in a way that
creates stable understandings.
As depicted by Piaget, the discontinuities of cognitive development involve four discrete
stages: (1) the sensorimotor stage (birth to age 2), in which infants begin to know the world

I N F O R M A T I O N – P R O C E S S I N G T H E O R I E S n 145
through the perceptions of their senses and through their motor activities; (2) the preopera-
tional stage (ages 2 to 7), in which children become capable of mental representations but
tend to be egocentric and to focus on a single dimension of an event or problem; (3) the
concrete operational stage (ages 7 to 12), in which children reason logically about concrete
aspects of the environment but have difficulty thinking abstractly; and (4) the formal opera-
tional stage (age 12 and beyond), in which preadolescents and adolescents become capable
of abstract thought.
Among the important strengths of Piaget’s theory are its broad overview of development,
its plausible and attractive perspective on children’s nature, its inclusion of varied tasks and
age groups, and its endlessly fascinating observations. Among the theory’s important weak-
nesses are its overstatement of the consistency of children’s thinking, its underestimation of
infants’ and young children’s cognitive competence, its lack of attention to the contribution
of the social world, and its vagueness regarding cognitive mechanisms.
Information-Processing Theories
SCENE: DAUGHTER AND FATHER IN THEIR YARD.
A PLAYMATE RIDES IN ON A BIKE.
Child: Daddy, would you unlock the basement door?
Father: Why?
C: ’Cause I want to ride my bike.
F: Your bike is in the garage.
C: But my socks are in the dryer.
(Klahr, 1978, pp. 181–182)
What reasoning could have produced this 5-year-old’s enigmatic comment, “But
my socks are in the dryer”? David Klahr, an eminent information-processing theo-
rist, formulated the following model of the thought process that led to it:
Top goal: I want to ride my bike.
Bias: I need shoes to ride comfortably.
Fact: I’m barefoot.
Subgoal 1: Get my sneakers.
Fact: The sneakers are in the yard.
Fact: They’re uncomfortable on bare feet.
Subgoal 2: Get my socks.
Fact: The sock drawer was empty this morning.
Inference: The socks probably are in the dryer.
Subgoal 3: Get them from the dryer.
Fact: The dryer is in the basement.
Subgoal 4: Go to the basement.
Fact: It’s quicker to go through the yard entrance.
Fact: The yard entrance is always locked.
Subgoal 5: Unlock the door to the basement.
Fact: Daddies have the keys to everything.
Subgoal 6: Ask Daddy to unlock the door.
Klahr’s analysis of his daughter’s thinking illustrates two notable character-
istics of information-processing theories.1 One is the precise specification of
the processes involved in children’s thinking. Klahr’s approach, for example, used
information-processing theories
n a class of theories that focus on the
structure of the cognitive system and the
mental activities used to deploy attention
and memory to solve problems
1 Here and throughout this section, we use the plural term “information-processing theories” rather than the singular
term “information-processing theory” because information-processing theories consist of a variety of related approaches
rather than a single set of unified ideas. For the same reason, in subsequent sections we refer to “sociocultural theories,”
and “dynamic-systems theories.”

146 n ChApTer 4 THEORIES OF COGNITIVE DEVELOPMENT
task analysis—that is, the identification of goals the obstacles that prevent their
immediate realization, the prior knowledge and information in the environment
relevant to them, and the potential processing strategies for overcoming the ob-
stacles and attaining the goals.
Such task analysis helps information-processing researchers understand and
predict children’s behavior and allows them to rigorously test precise hypothe-
ses regarding how development occurs. In some cases, it also allows them to for-
mulate computer simulations, a type of mathematical model that expresses ideas
about mental processes in particularly precise ways. For example, Simon and Klahr
(1995) created computer simulations of the knowledge and mental processes that
led young children to fail on conservation problems and of the somewhat different
knowledge and mental processes that allowed older children to succeed on them.
A second distinctive feature of information-processing analysis is an emphasis
on thinking as an activity that occurs over time. Often, a single simple behavior,
such as the initial request of Klahr’s daughter that he open the basement door, re-
flects an extended sequence of rapid mental operations. Information-processing
analyses identify what those mental operations are, the order in which they are ex-
ecuted, and how increasing speed and accuracy of mental operations lead to cogni-
tive growth.
View of Children’s Nature
Information-processing theorists see children’s cognitive growth as occurring con-
tinuously, in small increments that occur at different times on different tasks. This
depiction differs fundamentally from Piaget’s belief that children progress through
qualitatively distinct, broadly applicable stages, separated only by brief transition
periods.
The Child as a Limited-Capacity Processing System
In trying to understand differences in children’s thinking at various ages, some
information-processing theorists draw comparisons between the information
processing of computers and that of humans. A computer’s information process-
ing is limited by its hardware and by its software. The hardware limitations relate
to the computer’s memory capacity and its efficiency in executing basic operations.
The software limitations relate to the strategies and information that are available
for performing particular tasks. People’s thinking is limited by the same factors:
memory capacity, speed of thought processes, and availability of useful strategies
and knowledge. In the information-processing view, cognitive development arises
from children’s gradually surmounting their processing limitations through (1) ex-
pansion of the amount of information they can process at one time, (2) increases in
the speed with which they execute thought processes, and (3) acquisition of new
strategies and knowledge.
The Child as Problem Solver
Also central to the view of human nature held by information-processing theories
is the assumption that children are active problem solvers. As suggested by Klahr’s
analysis of his daughter’s behavior, problem solving involves goals, perceived ob-
stacles, and strategies or rules for overcoming the obstacles and attaining the goals.
A description of a younger child’s problem solving reveals the same combination of
goal, obstacle, and strategy:
task analysis n the research technique
of identifying goals, relevant information
in the environment, and potential pro-
cessing strategies for a problem
problem solving n the process of
attaining a goal by using a strategy to
overcome an obstacle

I N F O R M A T I O N – P R O C E S S I N G T H E O R I E S n 147
Georgie (a 2-year-old) wants to throw rocks out the kitchen window. The lawn
mower is outside. Dad says that Georgie can’t throw rocks out the window, because
he’ll break the lawnmower with the rocks. Georgie says, “I got an idea.” He goes out-
side, brings in some green peaches that he had been playing with, and says: “They
won’t break the lawnmower.”
(Waters, 1989, p. 7)
In addition to illustrating the typical goal–obstacle–strategy sequence, this ex-
ample highlights another basic tenet of information-processing approaches: chil-
dren’s cognitive flexibility helps them pursue their goals. Even young children show
great ingenuity in surmounting the obstacles imposed by their parents, the physical
environment, and their own lack of knowledge.
Central Developmental Issues
Like all the theories described in this chapter, information-processing theories ex-
amine how nature and nurture work together to produce development. What makes
information-processing theories unique is their emphasis on precise descriptions of
how change occurs. The way in which information-processing theories address the
issues of nature and nurture and how change occurs can be seen particularly clearly
in their accounts of the development of memory and problem solving.
The Development of Memory
Memory is crucial to everything we do. The skills we use on everyday tasks, the
language we employ when writing or speaking, the emotions we feel on a given
occasion—all depend on our memory of past experiences and the knowledge ac-
quired through them. Indeed, without memory of our experiences, we lose our very
identity, a devastating syndrome that has been observed in patients with certain
types of amnesia (Reed & Squire, 1998). Memory plays a role in all cognitive de-
velopmental theories, but it is especially central to information-processing theories.
Most such theories distinguish among working memory, long-term memory, and
executive functions.
Working memory Working memory involves actively attending to, gathering,
maintaining, storing, and processing information. For example, if after reading a
story about birds, a child were asked a question about it, the child would, through
working memory, bring together relevant information from the story, inferences
made from that information, and prior knowledge about birds, and would then
process the information to construct a reasonable answer.
Working memory is limited in both its capacity (the amount of information that
it can store) and in the length of time it can retain information without updating
activities. For example, a child might be able to remember a sequence of five dig-
its but not six, and might be able to remember them for 5 or 10 seconds without
repeating them but not for a longer time. The exact capacity and duration vary
with the task and the type of material being processed, but for a given task and
type of material, both capacity and speed increase with age and relevant experience
(Schneider, 2011).
The basic organization of working-memory subsystems seems to be constant
from early in childhood. However, the capacity and speed of operation of working
memory increase greatly over the course of childhood and adolescence (Cowan
et al., 1999; Gathercole et al., 2004). These changes are believed to occur in part
working memory n memory system
that involves actively attending to, gath-
ering, maintaining, storing, and pro-
cessing information

148 n ChApTer 4 THEORIES OF COGNITIVE DEVELOPMENT
because of increasing knowledge of the content on which working memory oper-
ates and in part because of maturational changes in the brain (Nelson, Thomas,
& De Haan, 2013; see Figure 4.8).
Long-term memory In contrast to the moment-to-moment nature of working
memory, long-term memory consists of the knowledge that people accumulate
over their lifetime. It includes factual knowledge (e.g., knowing the capitals of dif-
ferent countries or the teams that won the Super Bowl in the past 5 years), con-
ceptual knowledge (e.g., the concepts of justice, mercy, and equality), procedural
knowledge (e.g., knowing how to tie a shoe or play an Xbox game), attitudes (e.g.,
likes and dislikes regarding political parties or anchovies), reasoning strategies (e.g.,
knowing how to take an argument to its logical extreme to show its inadequacy),
and so on. Long-term memory can thus be thought of as the totality of one’s
knowledge, whereas working memory can be regarded as the subset of that knowl-
edge that is being processed at a given time (Cowan, 2005; Ericsson & Kintsch,
1995).
In contrast to the severe limits on the capacity and duration of working mem-
ory, long-term memory can retain an unlimited amount of information for unlim-
ited periods. To cite one notable example, research shows that people who studied
Spanish or algebra in high school often retain a substantial amount of what they
learned in the subject 50 years later, despite their not having used the information
in the interim and their having accumulated vast stores of other skills, concepts, and
knowledge in long-term memory over that period (Bahrick, 1987).
executive Functioning Executive functions involve the control of cognition. The
prefrontal cortex (Figure 4.8) plays a particularly important role in this cogni-
tive control. Three major types of executive functions are inhibiting tempting ac-
tions that would be counterproductive; enhancing working memory through use of
long-term memory n information
retained on an enduring basis
Temporal lobe
Primary motor cortex
Frontal lobe
Hippocampus
Cerebellum
Prefrontal cortex
Parietal lobe
Occipital lobe
FIGURE 4.8 All of the major
areas of the cortex shown here
continue maturing after birth.
Brain maturation continues for
a particularly long time in the
prefrontal cortex, an area that is
especially involved in planning,
inhibiting inappropriate behavior,
and adopting new goals in
response to changing situations.

I N F O R M A T I O N – P R O C E S S I N G T H E O R I E S n 149
strategies, such as repeating a phone number that would otherwise be forgotten;
and being cognitively flexible, for example, taking someone else’s perspective in an
argument despite its differing from one’s own. As these examples suggest, executive
functioning integrates information from working memory and long-term mem-
ory to accomplish goals (e.g., Diamond, 2013; Miyake & Friedman, 2012; Rose,
Feldman, & Jankowski, 2011).
The ability of executive functions to control thinking and action—enabling
the individual to respond appropriately rather than acting impulsively or doing
what he or she is used to doing—increases greatly during the preschool and early
elementary school years. One aspect of this improvement is children’s increased
cognitive flexibility in shifting goals. For instance, when they are assigned the
task of sorting toys by their color for a long period and then are asked to sort the
same toys by shape, most 3-year-olds have difficulty switching goals, but 5-year-
olds make the switch with ease (Baker, Friedman, & Leslie, 2010; Zelazo et al.,
2003).
The ability to inhibit habitual responses occurs slightly later and is evident in
everyday games such as “Simon Says.” Preschoolers have great difficulty inhibiting
the impulse to quickly respond to commands that are not preceded by the critical
phrase in such games, whereas early elementary school children are much better at
inhibiting the impulse to act immediately (Dempster, 1995; Diamond, Kirkham,
& Amso, 2002; Sabbagh et al., 2006). Strategies for controlling working memory
tend to develop a little later, largely in the first few years of elementary school
(Schneider, 2011).
As you might anticipate, the need for strong executive functioning continues to
pose challenges well beyond early childhood. For example, resisting the tempta-
tion to daydream while doing one’s homework, keeping quiet while the teacher is
talking, and inhibiting disrespectful replies to parents or teachers are difficult even
for many adolescents (Bunge & Zelazo, 2006; Munakata, Snyder, & Chat ham,
2011).
The quality of executive functioning during early childhood is highly predic-
tive of many important life outcomes years later, including academic achievement
in later grades, enrollment in college, and income and occupational status during
adulthood (Blair & Razza, 2007; Duncan et al., 2007; McClelland & Cameron,
2011; Mischel & Ayduk, 2011; Moffitt et al., 2011). Fortunately, several training
programs for preschoolers have shown considerable promise for improving young
children’s executive functioning (Diamond et al., 2007, 2013; Raver et al., 2009).
In one such training study, disadvantaged preschoolers were randomly as-
signed to classrooms using a curriculum designed to improve executive functioning
(Raver et al., 2011). The intervention involved instructing teachers in strategies—
including stating and implementing clear rules, rewarding positive behaviors, and
redirecting negative behaviors in positive directions—that would help children
inhibit impulses to disrupt classroom activities. By the end of the school year, this
approach had led to improvements in the children’s behavior and self-regulatory
skills. Even more impressive, for the next 3 years, children who had been in the in-
tervention classrooms continued to perform better in math and reading than did
children in a control group (Raver et al., 2011).
explanations of memory development Information-processing theorists try to
explain both the processes that make memory as good as it is at each age and the
limitations that prevent it from being better. These efforts have focused on three
types of capabilities: basic processes, strategies, and content knowledge.

150 n ChApTer 4 THEORIES OF COGNITIVE DEVELOPMENT
BASIC PROCESSES The simplest and most frequently used mental activities are
known as basic processes. They include associating events with one another, rec-
ognizing objects as familiar, recalling facts and procedures, and generalizing from
one instance to another. Another basic process, which is key to all the others, is
encoding —the representation in memory of specific features of objects
and events. With development, children execute basic processes more ef-
ficiently, enhancing their memory and learning for all kinds of materials.
Most of these basic processes are familiar, and their importance obvi-
ous. However, encoding is probably less familiar. Appreciating its signifi-
cance requires some understanding of the way in which memory works.
People often think of memory as something akin to an unedited video re-
cording of our experiences. Actually, memory is far more selective. People
encode information that draws their attention or that they consider rel-
evant, but they fail to encode a great deal of other information. Informa-
tion that is not encoded is not remembered later. This failure is probably
evident in your own memory of the American flag; although you have
seen it many times, you most likely have not encoded how the stars are
arranged.
Studies of how children learn to solve balance-scale problems illustrate
the importance of encoding for learning and memory. As discussed on
page 139, most 5-year-olds predict that the side of the scale with more
weight will go down, regardless of the distance of the weights from the ful-
crum. Five-year-olds generally have difficulty learning more advanced ap-
proaches to solving balance-scale problems that take into account distance
as well as weight, because they do not encode information about distance
of the weights from the fulcrum. For example, 5-year-olds are shown a balance
scale with varying arrangements of weights on pegs; the scale is then hidden behind
a barrier, and the children are asked to reproduce the arrangement on an identical
balance scale. Five-year-olds generally reproduce the correct number of weights on
each side but rarely put them the correct distance from the fulcrum (Siegler, 1976).
Teaching them to encode distance by telling them that both weight and distance
are important enables them to learn more advanced balance-scale rules that peers
who were not taught to encode distance have trouble learning (Siegler & Chen,
1998).
basic processes n the simplest and
most frequently used mental activities
encoding n the process of representing
in memory information that draws atten-
tion or is considered important
Misencoding common sayings can lead to
memorable confusions.
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FIGURE 4.9 Increase with age in speed
of processing on two tasks Note that the
increase is rapid in the early years and more
gradual later. (Data from Kail, 1991)
9 108
Age in years
(a) Mental Rotation
11 12 13 14 15 16 17 18 19 20 21 22
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“Mirror, mirror, on the wall, who’s the fairest of the mall?”
The FAMILY CIrCUS By Bil Keane

I N F O R M A T I O N – P R O C E S S I N G T H E O R I E S n 151
Like improved encoding, improved speed of processing plays a key role in the
development of memory and learning. As shown in Figure 4.9, processing speed
increases most rapidly at young ages but continues to increase in adolescence (Kail,
1991, 1997; Luna et al., 2004).
Two biological processes that contribute to faster processing are myelination
and increased connectivity among brain regions (Luna et al., 2004). As discussed
in Chapter 3, from the prenatal period through adolescence, increasing numbers of
axons of neurons become covered with myelin, the fatty insulating substance that
promotes faster and more reliable transmission of electrical impulses in the brain
(Paus, 2009). Myelination enhances executive function, contributing to the ability
to resist distractions (Dempster & Corkill, 1999; Wilson & Kipp, 1998). Greater
connectivity among brain regions also increases processing capacity and speed by
increasing the efficiency of communication among brain areas (Thatcher, 1998).
This growth of long-distance connectivity among brain regions is especially promi-
nent in later childhood and adolescence.
STRATEGIES Information-processing theories point to the acquisition and growth
of strategies as another major source of the development of memory. Between ages
5 and 8 years, children begin to use a number of broadly useful memory strategies,
among them the strategy of rehearsal, the repeating of information multiple times
in order to remember it. The following newspaper item illustrates the usefulness of
rehearsal for remembering information verbatim:
A 9-year-old boy memorized the license plate number of a getaway car following an
armed robbery, a court was told Monday. . . . The boy and his friend . . . looked in the
drug store window and saw a man grab a 14-year-old cashier’s neck. . . . After the
robbery, the boys mentally repeated the license number until they gave it to police.
(Edmonton Journal, Jan. 13, 1981, cited in Kail, 1984)
Had the boys witnessed the same event when they were 5-year-olds, they prob-
ably would not have rehearsed the numbers and would have forgotten the license
number before the police arrived.
Another widely used memory strategy that becomes increasingly prevalent in the
early elementary school years is selective attention, the process of intentionally fo-
cusing on the information that is most relevant to the current
goal. If 7- and 8-year-olds are shown objects from two different
categories (e.g., several toy animals and several household items)
and are told that they later will need to remember the objects in
only one category (e.g., “You’ll need to remember the animals”),
they focus their attention on the objects in the specified category
and remember more of them. In contrast, given the same instruc-
tions, 4-year-olds pay roughly equal attention to the objects in
both categories, which reduces their memory for the objects they
need to remember (DeMarie-Dreblow & Miller, 1988).
CONTENT KNOWLEDGE With age and experience, children’s knowl-
edge about almost everything increases. This increase in knowl-
edge in long-term memory improves recall of new material by
making it easier to integrate new material with existing under-
standing (Pressley & Hilden, 2006). The importance of con-
tent knowledge to memory is illustrated by the fact that when
children know more about a topic than adults do, their memory
for new information about the topic often is superior to the
Through repeated visits to doctors’ offices
and through other experiences that occur
in more or less fixed sequences, children
gain content knowledge that improves their
memory for subsequent, similar events.
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rehearsal n the process of repeating
information multiple times to aid memory
of it
selective attention n the process of
intentionally focusing on the information
that is most relevant to the current goal

152 n ChApTer 4 THEORIES OF COGNITIVE DEVELOPMENT
adults’. For example, when children and adults are provided new information about
children’s TV programs and books, the children generally remember more of the
information than do the adults (Lindberg, 1980, 1991). Similarly, children who
know a lot about soccer learn more from reading new soccer stories than do other
children who are both older and have higher IQs but who know less about soccer
(Schneider, Körkel, & Weinert, 1989).
Prior content knowledge improves memory for new information in several dif-
ferent ways. One is by improving encoding. In tests of memory of various arrange-
ments of chess pieces on a board, child chess experts remember far more than do
adult novices. The reason is that the child experts’ greater knowledge of chess leads
to their encoding higher-level chunks of information that include the positions
of several pieces relative to one another rather than encoding the location of each
piece separately (Chi & Ceci, 1987). Content knowledge also improves memory
by providing useful associations. A child who is knowledgeable about birds knows
that type of beak and type of diet are associated, so remembering either one in-
creases memory for the other ( Johnson & Mervis, 1994). In addition, content
knowledge indicates what is and is not possible and therefore guides memory in
useful directions. For example, when people familiar with baseball are asked to re-
call a particular inning of a game that they watched and they can remember only
two outs in that inning, they recognize that there must have been a third out and
search their memories for it; people who lack baseball knowledge do not (Spilich
et al., 1979).
The Development of Problem Solving
As noted earlier, information-processing theories depict children as active problem
solvers whose use of strategies often allows them to overcome limitations of knowl-
edge and processing capacity. In this section, we present an information-processing
perspective on the development of problem solving—the overlapping-waves theory.
Piaget’s theory depicted children of a given age as using a particular strategy to solve
a particular class of problems. For example, he described 5-year-olds as “solving”
conservation-of-number problems (see Figure 4.6) by choosing the longer row of
objects, and 7-year-olds as solving the same problems by reasoning that if nothing
was added or subtracted, the number of objects must remain the same. According
to overlapping-waves theory, however, children
actually use a variety of approaches to solve this
and other problems (Siegler, 1996). For instance,
examining 5-year-olds’ reasoning on repeated
trials of the conservation-of-number problem
reveals that most children use at least three dif-
ferent strategies (Siegler, 1995). The same child
who on one trial incorrectly reasons that the lon-
ger row must have more objects will on other
trials correctly reason that just spreading a row
does not change the number of objects, and on
yet other trials will count the number of objects
in the two rows to see which has more.
Figure 4.10 presents the typical pattern of de-
velopment envisioned by the overlapping-waves
approach, with strategy 1 representing the sim-
plest strategy, and strategy 5, the most advanced.
Strategy 1
Strategy 4
Strategy 5
Strategy 3
Strategy 2
Younger Older
Age
Less
More
P
er
ce
n
t
u
se
FIGURE 4.10 The overlapping-waves
model The overlapping-waves model pro-
poses that, at any one age, children use
multiple strategies; that with age and
experience, they rely increasingly on more
advanced strategies (the ones with the
higher numbers); and that development
involves changes in use of existing strategies
as well as discovery of new approaches.
overlapping-waves theory n an infor-
mation-processing approach that empha-
sizes the variability of children’s thinking

I N F O R M A T I O N – P R O C E S S I N G T H E O R I E S n 153
At the youngest age depicted, children usually use strategy 1, but they sometimes
use strategy 2 or 4. With age and experience, the strategies that produce more suc-
cessful performances become more prevalent; new strategies also are generated and,
if they are more effective than previous approaches, are used increasingly. Thus, by
the middle of the age range in Figure 4.10, children have added strategies 3 and 5
to the original group and have almost stopped using strategy 1.
This model has been shown to accurately characterize children’s problem solv-
ing in a wide range of contexts, including arithmetic, time-telling, reading, spell-
ing, scientific experimentation, biological understanding, tool use, and recall from
memory (Chen & Siegler, 2000; Kuhn & Franklin, 2006; Lee & Karmiloff-Smith,
2002; Miller & Coyle, 1999).
The overlapping-waves approach specifies several ways in which problem solv-
ing improves over the course of development. Children discover new strategies that
are more effective than their previous ones, they learn to execute both new and old
strategies more efficiently, and they choose strategies that are more appropriate to
the particular situation (Miller & Coyle, 1999; Siegler, 2006).
All these sources of cognitive growth are evident in learning addition. During
kindergarten and the first few years of elementary school, children’s knowledge of
single-digit addition improves greatly. One reason is that children discover new
strategies, such as counting-on (e.g., solving 2 1 9 by thinking “9, 10, 11”). An-
other source of improvement is faster and more accurate execution of all the strate-
gies that children know (e.g., retrieval of answers from memory, counting from one,
and counting-on). A third source of improvement is that children choose among
strategies increasingly adaptively (e.g., using counting-on most often on problems
with a large difference between the addends, such as 2 1 9, and counting from one
on problems such as 7 1 8, which are difficult for them to solve correctly by using
the other strategies they know (Geary, 2006; Siegler, 1987; Sieger & Jenkins, 1989).
(Box 4.2 illustrates how information-processing analyses can improve education.)
planning Problem solving is often more successful if people plan before acting.
Children benefit from planning how to get to friends’ houses, how to get their way
with parents, and how to break bad news to others in ways that are least likely to
trigger angry reactions (Hudson, Sosa, & Schapiro, 1997). Despite the advantages of
planning, however, children, and even adolescents, often fail to plan in situations in
which it would help their problem solving (Berg et al., 1997). The question is why.
Information-processing analyses suggest that one reason planning is difficult for
children is that it requires inhibiting the desire to solve the problem immediately in
favor of first trying to construct the best strategy. Starting to work on an assigned
paper without planning what will be written in the paper is one familiar example.
A second reason planning is difficult for young children is that they tend to be
overly optimistic about their abilities and think that they can solve problems more
effectively than their capabilities actually allow (Bjorklund, 1997; Schneider, 1998).
This overconfidence can lead them to not plan, because they think they will suc-
ceed without doing so. Such overoptimism can lead young children to act rashly.
For instance, 6-year-olds who overestimate their physical abilities have more ac-
cidents than do peers who evaluate their abilities more realistically, presumably
because their confidence leads them not to plan how to avoid potential dangers
(Plumert, 1995).
Over time, maturation of the prefrontal cortex, a part of the brain that is espe-
cially important for planning, along with experiences that reduce overoptimism or
demonstrate the value of planning, lead to increases in the frequency and quality
Young children’s overoptimism sometimes
leads them to engage in dangerous activi-
ties. This particular plan worked out fine,
but not all do.
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154 n ChApTer 4 THEORIES OF COGNITIVE DEVELOPMENT
BOX 4.2: applications
EDUCATIONAL APPLICATIONS OF INFORMATION-
PROCESSING THEORIES
Children’s knowledge of numbers when they
begin kindergarten predicts their mathemat-
ics achievement years later—in elementary
school, middle school, and even high school
(Duncan et al., 2007; Stevenson & Newman,
1986). It is especially unfortunate, then, that
kindergartners from low-income families lag
far behind middle-income peers in counting,
number recognition, arithmetic, and knowl-
edge of numerical magnitudes (e.g., under-
standing that 7 is less than 9 and that both
are closer to 10 than to 0 on a number line).
What might account for these early differ-
ences in numerical knowledge of children
from different economic backgrounds? An
information-processing analysis suggested
that experience playing numerical board
games such as Chutes and Ladders might
be important. In Chutes and Ladders, play-
ers must move a token across 100 consecu-
tively numbered squares, advancing on each
of their turns by the number of spaces deter-
mined by a spinner. The higher the number
of the square on which a child’s token rests
at any given point in the game, the greater
the number of number names the child
will have spoken and heard, the greater the
distance the child will have moved the token
from the first square, the greater the time
the child will have been playing the game,
and the greater the number of discrete hand
movements with the token the child will
have made. These verbal, spatial, tempo-
ral, and kinesthetic cues provide a broadly
based, multisensory foundation for knowl-
edge of numerical magnitudes, a type of
knowledge that is closely related to math-
ematics achievement test scores (Booth &
Siegler, 2006, 2008; Geary, 2011).
Ramani and Siegler (2008) applied this
information-processing analysis to improving
the numerical understanding of low-income
preschoolers. The researchers randomly as-
signed 4- and 5-year-olds from low-income
families to either an experimental number-
board condition or a control color-board
condition. The number-board condition
was virtually identical to the first row of the
Chutes and Ladders board; it included 10
squares numbered consecutively from left to
right. On each turn, the child spun a dial that
yielded a “1” or a “2” and moved his or her
token the corresponding number of squares
on the board, stating the number on each
square in the process. For example, if a play-
er’s token was on the square with the “4,”
and the player spun a “2,” the player would
say, “5, 6” while moving the token from the
“4” to the “6.” Children in the color-board
condition played the same game, except that
their board had no numbers and the play-
ers would say the name of the color of each
square as they advanced their token. Chil-
dren in both conditions were given a pretest
that examined their knowledge of numbers
before playing the game, and then played
the game for four 15- minute sessions over a
2-week period. At the end of the fourth ses-
sion, the children were given a posttest on
their knowledge of numbers; 9 weeks later,
they were given a follow-up test identical to
the pretest and posttest.
On the posttest, children who played
the number board game showed improved
knowledge of the numbers 1 through 10 on
all four tasks that were presented— counting,
reading of numbers, magnitude comparisons
(e.g., “Which is bigger, 8 or 3?”), and es-
timates of the locations of numbers on a
number line. Significantly, all the gains were
maintained on the follow-up test 9 weeks
later. In contrast, children who played the
color board game showed no improvement in
any aspect of number knowledge. Moreover,
children’s reports of how often they played
Chutes and Ladders and other board games
at home was positively correlated with their
initial knowledge on all four numerical tasks,
and middle-income children reported play-
ing numerical board games (though not video
games) much more often than children from
low-income backgrounds.
Subsequent studies demonstrated that
playing the 1–10 board game also improves
preschoolers’ ability to learn the answers to
arithmetic problems, such as that 2 1 4 5
6 (Siegler & Ramani, 2009). Taken together,
the evidence suggests that numerical board
games represent a quick, effective, and in-
expensive means of improving the numeri-
cal knowledge of low-income children before
they start school.
playing this number board game improves preschoolers’ numerical
knowledge.
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S O C I O C U L T U R A L T H E O R I E S n 155
of planning, which improves problem solving (Chalmers & Lawrence, 1993). The
improvements in the planning process take a long time, however; even 12-year-
olds leave less distance between themselves and oncoming vehicles than adults do
(Plumert, Kearney, & Cremer, 2004).
review:
Information-processing theories envision children as active learners and problem solvers who
continuously devise means for overcoming their processing limits and reaching their goals.
The capacity and processing speed of working memory and long-term memory influence all
information processing. Executive functioning uses information in working memory and long-
term memory to flexibly shift goals and inhibit impulses to behave in ways that are inappro-
priate in the situation; it also updates the contents of working memory so that new goals can
be pursued effectively. Cognitive growth in general, and development of memory and learning
in particular, are seen as involving increasingly efficient execution of basic processes, con-
struction of more effective strategies, and acquisition of new content knowledge. Overlapping
waves theory indicates that individual children use multiple strategies to solve the same type
of problem, that children choose adaptively among these strategies, and that problem solving
improves through the discovery of more effective strategies, more efficient execution of the
strategies, better choices of when to use the strategies, and improved planning.
Sociocultural Theories
A mother and her 4-year-old daughter, Sadie, assemble a toy, using a diagram to
guide them:
Mother: Now you need another one like this on the other side. Mmmmm . . .
there you go, just like that.
Sadie: Then I need this one to go like this? Hold on, hold on. Let it go. There.
Get that out. Oops.
M: I’ll hold it while you turn it. (Watches Sadie work on toy) Now you make
the end.
S: This one?
M: No, look at the picture. Right here (points to diagram). That piece.
S: Like this?
M: Yeah.
(Gauvain, 2001, p. 32)
This interaction probably strikes you as completely unexceptional—and it is.
From the perspective of sociocultural theories, however, it and thousands of other
everyday interactions like it are of the utmost importance, because they are the en-
gines of development.
One noteworthy characteristic of the event, from the sociocultural perspective, is
that Sadie is learning to assemble the toy in an interpersonal context. Sociocultural
theorists emphasize that much of cognitive development takes place through direct
interactions between children and other people—parents, siblings, teachers, play-
mates, and so on—who want to help children acquire the skills and knowledge val-
ued by their culture. Thus, whereas Piagetian and information-processing theories
emphasize children’s own efforts to understand the world, sociocultural theories em-
phasize the developmental importance of children’s interactions with other people.
The interaction between Sadie and her mother is also noteworthy because it ex-
emplifies guided participation, a process in which more knowledgeable individuals
sociocultural theories n approaches
that emphasize that other people and the
surrounding culture contribute greatly to
children’s development
guided participation n a process in
which more knowledgeable individuals
organize activities in ways that allow less
knowledgeable people to learn

156 n ChApTer 4 THEORIES OF COGNITIVE DEVELOPMENT
organize activities in ways that allow less knowledgeable people to engage
in them at a higher level than they could manage on their own (Rogoff,
2003). Sadie’s mother, for example, holds one part of the toy so that Sadie
can screw in another part. On her own, Sadie would be unable to screw
the two parts together and therefore could not improve her skill at the
task. Similarly, Sadie’s mother points to the relevant part of the diagram,
enabling Sadie to decide what to do next and also to learn how diagrams
convey information. As this episode illustrates, guided participation often
occurs in situations in which the explicit purpose is to achieve a practi-
cal goal, such as assembling a toy, but in which learning occurs as a by-
product of the goal-directed activity.
A third noteworthy characteristic of the interaction between Sadie
and her mother is that it occurs in a broader cultural context. This con-
text includes not only other people but also the innumerable products of
human ingenuity that sociocultural theorists refer to as cultural tools:
symbol systems, artifacts, skills, values, and so on. In the example of Sadie
and her mother, the relevant symbol systems include the language they
use to convey their thoughts and the diagram they use to guide their as-
sembly efforts; the relevant artifacts include the toy and the printed sheet
on which the diagram appears; the relevant skills include the proficiency
in language that allows them to communicate with each other and the
procedures they use to interpret the diagram; and the values include the
culture’s approval of parents interacting with their children in the way
that Sadie’s mother does and of young girls’ learning mechanical skills. In
the background are an array of broader technological, economic, and historical fac-
tors: the technology needed to manufacture toys and print diagrams, for example;
an economy that allows parents the leisure time for such interactions; and a his-
tory leading up to the symbol systems, artifacts, skills, and values reflected in the
interactions between Sadie and her mother. Thus, sociocultural theories can help
us appreciate the many aspects of culture embodied in even the smallest everyday
interactions.
View of Children’s Nature
The giant of the sociocultural approach to cognitive development, and in many
ways its originator, was the Russian psychologist Lev Semyonovich Vygotsky. Al-
though Vygotsky and Piaget were contemporaries, much of Vygotsky’s most im-
portant work was largely unknown outside Russia until the 1970s. Its appearance
created a stir, in part because Vygotsky’s view of children’s nature was so different
from Piaget’s.
Vygotsky’s Theory
As noted earlier, Piaget depicted children as little scientists, trying to understand
the world on their own. Vygotsky, in contrast, portrayed them as social learners,
intertwined with other people who are eager to help them gain skills and under-
standing. Whereas Piaget viewed children as intent on mastering physical, math-
ematical, and logical concepts that are the same in all times and places, Vygotsky
viewed them as intent on participating in activities that happen to be prevalent in
their local setting. Whereas Piaget emphasized qualitative changes in thinking,
Vygotsky emphasized continuous, quantitative changes. These Vygotskian views
Through guided participation, parents can
help children not only accomplish imme-
diate goals but also learn skills, such as how
to use written instructions and diagrams to
assemble objects.
IM
A
G
E
S
O
U
R
C
E
P
LU
S
/
A
LA
M
Y
The russian psychologist Lev Vygotsky, the
founder of the sociocultural approach to
child development.
D
A
V
ID
S
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N
F
IL
M
S
,
IN
C
.

S O C I O C U L T U R A L T H E O R I E S n 157
gave rise to the central metaphor of sociocultural theories: children as social learn-
ers, shaped by, and shaping, their cultural contexts.
Vygotsky’s emphasis on children as social learners is evident in his perspective
on the relation between language and thought. Whereas Piaget viewed the two as
largely unrelated, Vygotsky (1934/1962) viewed them as integrally related. In par-
ticular, he believed that thought is internalized speech and that thought originates
in large part in statements that parents and other adults make to children.
To illustrate the process of internalizing speech, Vygotsky described three phases
of its role in the development of children’s ability to regulate their own behavior
and problem solving. At first, children’s behavior is controlled by other people’s
statements (as in the example of Sadie and her mother assembling the toy); then,
children’s behavior is controlled by their own private speech, in which they tell
themselves aloud what to do, much as their parents might have done earlier; and
then, their behavior is controlled by internalized private speech (thought), in which
they silently tell themselves what to do. The transition between the second and
third phases often involves whispers or silent lip movements; in Vygotsky’s terms,
the speech “goes underground” and becomes thought.
Private speech is most prevalent between ages 4 and 6 years, although older chil-
dren and adults also use it on challenging tasks, such as assembling model airplanes
or following complex directions (Winsler et al., 2003). In addition, the progression
from external to internalized speech emerges not only with age but also with experi-
ence; children generate a considerable amount of overt private speech when they first
encounter a challenging task, but the amount lessens as they master it (Berk, 1994).
Children as Teachers and Learners
Contemporary sociocultural theorists, such as Michael Tomasello (2001; 2009), have
extended Vygotsky’s insights. Tomasello proposed that the human species has two
unique characteristics that are crucial to the ability to create complex, rapidly chang-
ing cultures. One of these is the inclination to teach others of the species; the other
is the inclination to attend to and learn from such teaching. In every human society,
adults communicate facts, skills, values, and traditions to their young. This is what
makes culture possible; as Isaac Newton noted, it enables the new generation to
stand on the shoulders of the old and thus to see farther.
The inclination to teach emerges very early: all normal
2-year-olds spontaneously point to and name objects to
call other people’s attention to what they themselves find
interesting. Only humans engage in such rudimentary
teaching behaviors that are not directly tied to survival.
This inclination to teach and to learn from teaching is
what enables children to be socialized into their culture
and to pass that culture on to others.
Children as Products of Their Culture
Sociocultural theorists believe that many of the processes
that produce development, such as guided participation,
are the same in all societies. However, the content that
children learn—the particular symbol systems, artifacts,
skills, and values—vary greatly from culture to culture
and shape thinking accordingly.
cultural tools n the innumerable prod-
ucts of human ingenuity that enhance
thinking
private speech n the second phase
of Vygotsky’s internalization-of-thought
process, in which children develop their
self-regulation and problem-solving abili-
ties by telling themselves aloud what to
do, much as their parents did in the first
stage
The inclination to teach and the ability to
learn from teaching are among the most dis-
tinctly human characteristics.
G
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LL
O
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M
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G
E
S
/
D
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G
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158 n ChApTer 4 THEORIES OF COGNITIVE DEVELOPMENT
One example of the impact of culturally specific content comes from a study of
analogical reasoning, a process in which experience with previously encountered
problems is applied to new problems. In the study (Chen, Mo, & Honomichl,
2004), American and Chinese college students were asked to solve two problems.
One problem required a solution analogous to the strategy of leaving a trail of
white pebbles to follow home from the woods in “Hansel and Gretel,” a tale well
known to the American students but unknown to the Chinese. The American
students were far more successful in solving that problem, and many of them al-
luded to the fairy tale even though they had not heard it in many years. The other
problem required a solution analogous to that in a fairy tale that was well known
to the Chinese students but unknown to the Americans. In this case, the Chinese
students were vastly superior in solving the problem, and many alluded to the rel-
evant fairy tale.
Children’s memories of their own experiences also reflect their culture. When
4- to 8-year-olds from China and the United States were asked to describe their
earliest memories, their descriptions differed in ways that reflected their culture’s
attitudes and values (Wang, 2007). Chinese culture prizes and promotes interde-
pendence among people, especially among close relatives. European American cul-
ture, in contrast, prizes and promotes the independence of individuals. Consistent
with these cultural emphases, the Chinese children’s reports of their earliest memo-
ries included more references to other people than did those of American children,
and the American children’s reports included more references to the child’s own
feelings and reactions. Thus, the attitudes and values of a culture, as well as its arti-
facts and technologies, shape the thoughts and memories of people in that culture.
Central Developmental Issues
Vygotsky and contemporary sociocultural theorists have proposed a number of spe-
cific ideas about how change occurs through social interaction. One of these ideas—
guided participation—has already been discussed. In this section, we examine two
related concepts that play prominent roles in sociocultural analyses of change: in-
tersubjectivity and social scaffolding.
As illustrated by this photo of an east
Asian father teaching his children to use
an abacus, the tools available in a culture
shape the learning of children within that
culture.
A
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/
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M
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E
T

S O C I O C U L T U R A L T H E O R I E S n 159
Intersubjectivity
Sociocultural theorists believe that the foundation of human cog-
nitive development is our ability to establish intersubjectivity, the
mutual understanding that people share during communication
(Gauvain, 2001; Rommetveit, 1985). The idea behind this im-
posing term is both simple and profound: effective communica-
tion requires participants to focus on the same topic, and also on
each other’s reaction to whatever is being communicated. Such a
“meeting of the minds” is indispensable for effective teaching and
learning.
The roots of intersubjectivity are evident early in infancy. By age
6 months, infants can learn novel behaviors by observing another
person’s behavior, which requires attending to the same actions as
the person executing the actions (Collie & Hayne, 1999).
This and related developments in early infancy set the stage for
the emergence of a process that is at the heart of intersubjectivity—
joint attention. In this process, infants and their social partners
intentionally focus on a common referent in the external environ-
ment. The emergence of joint attention is evident in numerous
ways. Around their first birthday, infants increasingly look toward
objects that are the targets of their social partners’ gaze, even if
the partner is not acting on the objects, and actively direct a part-
ner’s attention toward objects that they themselves find interesting
(Adamson, Bakeman, & Deckner, 2004; Akhtar & Gernsbacher,
2008; Moore, 2008).
Joint attention greatly increases children’s ability to learn from other people.
One important example involves language learning. When an adult tells a tod-
dler the name of an object, the adult usually looks or points directly at it; children
who are looking at the same object are in a better position to learn what the word
means than ones who are not (Baldwin, 1991). Indeed, the degree of success infants
have in following other people’s gaze predicts their later vocabulary development
(Brooks & Meltzoff, 2008) and their subsequent language development more gen-
erally (Carpenter, Nagell, & Tomasello, 1998).
Intersubjectivity continues to develop well beyond infancy, as children become
increasingly able to take the perspectives of other people. For example, 4-year-olds
are more likely than 3-year-olds to reach agreement with peers on the rules of a
game they are about to play and the roles that each child will assume in the game
(Göncü, 1993). The continuing development of such perspective-taking abilities
also leads to school-aged children’s increasing ability to teach and learn from one
another (Gau vain, 2001).
Social Scaffolding
When putting up tall buildings, construction workers use metal frameworks
called scaffolds, which allow them to work high above the ground. Once a build-
ing’s main structure is in place, it can support further work on its own, thus allow-
ing the scaffolding to be removed. In an analogous fashion, children’s learning is
aided by social scaffolding, in which more competent people provide a tempo-
rary framework that supports children’s thinking at a higher level than children
could manage on their own (Wood, Bruner, & Ross, 1976). Ideally, supplying this
Joint attention, the process through which
social partners focus on the same external
object, underlies the human capacity to
teach and to learn from teaching.
P
H
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D
IS
C
/
T
H
IN
K
S
T
O
C
K
intersubjectivity n the mutual under-
standing that people share during
communication
joint attention n a process in which
social partners intentionally focus on
a common referent in the external
environment
social scaffolding n a process in which
more competent people provide a tempo-
rary framework that supports children’s
thinking at a higher level than children
could manage on their own

160 n ChApTer 4 THEORIES OF COGNITIVE DEVELOPMENT
framework includes explaining the goal of the task, demonstrating
how the task can be done, and helping the child with the most dif-
ficult parts of the task. This, in fact, is the way parents tend to teach
their children (Pratt et al., 1988; Saxe, Guberman, & Gearhart,
1987; Wood, 1986).
Through the process of social scaffolding, children become capable
of working at a higher level than if they had not received such help.
At first, this higher-level functioning requires extensive support, then
it requires less and less support, and eventually it becomes possible
without any support. The higher the quality of the scaffolding—that
is, the more that instructional efforts are directed at the upper end
of the child’s capabilities—the greater the learning (Conner, Knight,
& Cross, 1997; Gauvain, 2001). The goal of social scaffolding—to
allow children to learn by doing—is the same as that of guided par-
ticipation, but scaffolding tends to involve more explicit instruction
and explanation, whereas guided participation tends to involve adults’
organizing tasks so that children can take increasingly active and re-
sponsible roles in them.
One particularly important way in which parents use scaffold-
ing is in helping children form autobiographical memories, that
is, explicit memories of events that took place at specific times and
places in the individual’s past (Nelson & Fivush, 2004). Autobio-
graphical memories include information about one’s goals, inten-
tions, emotions, and reactions relative to these events. Over time,
these memories become strung together into a more or less coherent narrative
about one’s life.
When discussing past experiences with their young children, some mothers en-
courage them to provide many details about past events and often expand on the
children’s statements. Such a mother might reply to her toddler’s statement “Bird
fly away” by saying, “Yes, the bird flew away because you got close to it and scared
it.” Such statements help children remember their experiences by improving their
encoding of key information (distance from the bird) and their appreciation of the
causal relations among events (Boland, Haden, & Ornstein, 2003; McGuigan &
Salmon, 2004). Other mothers ask fewer questions and rarely elaborate on what
their children say. Children whose mothers use the more elaborative style remem-
ber more about the events than do children whose mothers rarely elaborate (Haden,
Hayne, & Fivush, 1997; Harley & Reese, 1999; Leichtman et al., 2000). (As dis-
cussed in Box 4.3, concepts from sociocultural theories have also proved useful for
improving education in classrooms.)
review:
Sociocultural approaches view children as social learners, shaped by, and shaping, their cul-
tural contexts. These approaches emphasize that children develop in a cultural context of
other people and human inventions, such as symbol systems, artifacts, skills, and values.
Through guided participation, more knowledgeable people help children gain skills in using
these cultural tools; children’s use of the tools, in turn, further transforms their thinking. Cul-
ture is made possible by the human propensity to teach and learn and to establish intersub-
jectivity with other people. Through processes such as social scaffolding and the creation of
communities of learners, older and more skilled individuals help children acquire the skills,
knowledge, and values of their culture.
By providing their children with social scaf-
folding, parents enable them to play with
toys and other objects in more advanced
ways than would otherwise be possible,
which helps the children learn.
©
S
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/
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B
IS
autobiographical memories n memo-
ries of one’s own experiences, including
one’s thoughts and emotions

D Y N A M I C – S Y S T E M S T H E O R I E S n 161
Dynamic-Systems Theories
Like all biological processes, thinking serves an adaptive purpose: it enables people
and other animals to devise plans for attaining goals. However, attaining goals also
requires the ability to take effective action; without this ability, thinking would be
pointless. For example, what purpose would planning serve for an organism that
could not implement the plans through action (see Figure 4.11)? Despite this in-
herent connection between thinking and acting, however, most theories of cogni-
tive development have ignored the development of the skilled actions that allow
children to realize the fruits of their mental labor.
One increasingly influential exception to this generalization is dynamic-
systems theories, a class of theories that focuses on how change occurs over time
in complex systems. Research that reflects the dynamic-systems perspective indi-
cates that detailed analyses of the development of infants’ basic actions, such as
crawling, walking, reaching, and grasping, yield surprising and impressive insights
into how development occurs. For example, dynamic-systems research has shown
BOX 4.3: applications
EDUCATIONAL APPLICATIONS
OF SOCIOCULTURAL THEORIES
For some time, the educational system of
the United States has been criticized for
promoting rote memorization of facts rather
than deep understanding; for promoting
competition rather than cooperation among
students; and for generally failing to create
enthusiasm for learning (National Associa-
tion for the Education of Young Children,
2011; Pellegrino, Chudowsky, & Glaser,
2001). The emphasis of sociocultural theo-
ries on the role of culture in learning im-
plies that one way to improve schooling is to
change the culture of schools. The culture
should be one in which instruction is aimed
at helping children gain deep understand-
ing, in which learning is a cooperative ac-
tivity, and in which learning a little makes
children want to learn more.
One impressive attempt to meet these
goals is Ann Brown’s (1997) community-of-
learners program. Its efforts to build com-
munities of learners have focused on 6- to
12-year-olds, most of them African Amer-
ican children attending inner-city schools
in Boston, Massachusetts, and Oakland,
California. The main curriculum consists of
projects that require research on some large
topic, such as interdependence between
animals and their habitats. The class di-
vides into small groups, each of which fo-
cuses on a particular aspect of the topic.
With the topic of the interdependence be-
tween animals and habitats, for example,
one group might study predator–prey rela-
tions; another, reproductive strategies; an-
other, protection from the elements; and
so on.
At the end of roughly 10 weeks, new
groups are formed, each including one
child from every original group. Children
in the new groups are asked to solve a
problem that encompasses all the aspects
studied by the previous groups, such as
designing an “animal of the future” that
would be particularly well adapted to its
habitat. Because each child’s participation
in the previous group has resulted in the
child’s gaining expertise on the aspect of
the problem studied by that group, and be-
cause no other child in the new group has
that expertise, all of the children’s contri-
butions are essential for the new group to
succeed. Aronson (1978) labeled this tech-
nique the jigsaw approach, because, as in
a jigsaw puzzle, each piece is necessary for
the solution.
A variety of people help foster such com-
munities of learners. Classroom teachers in-
troduce the big ideas of the unit, encourage
children to pool their knowledge to achieve
deeper understanding, push them to provide
evidence for their opinions, and ask them
to summarize what they know and to iden-
tify new learning goals. Outside experts are
at times brought to classrooms to lecture
and answer questions about the topic. Chil-
dren at other schools, who are working on
the same problem, are contacted via email
to see how they are approaching issues that
arise.
Communities of learners provide both cog-
nitive and motivational benefits for children.
Participation in such groups helps children
become increasingly adept at construct-
ing high-quality solutions to the problems
they try to solve. It also helps them learn
such general skills as identifying key ques-
tions and comparing alternative solutions to
a problem. Finally, because the children all
depend on one another’s contributions, the
community-of-learners approach encourages
mutual respect and individual responsibility
for the success of the entire group. In short,
the approach creates a culture of learning.
dynamic-systems theories n a class
of theories that focus on how change
occurs over time in complex systems

162 n ChApTer 4 THEORIES OF COGNITIVE DEVELOPMENT
that improved reaching allows infants to play with objects in more advanced ways,
such as organizing them into categories or interesting configurations (Spencer et
al., 2006; Thelen & Corbetta, 1994). Dynamic-systems research also has shown
that the onset of crawling changes infants’ relationships with family members,
who may be thrilled to see their baby attain an important motor milestone but
also find themselves having to be much more watchful and controlling to avoid
harm to the child and to the objects in the child’s path (Campos, Kermoian, &
Zumbahlen, 1992).
Another contribution of dynamic-systems research has been to demonstrate that
the development of seemingly simple actions is far more complex and interesting
than previously realized. For example, such research has overturned the traditional
belief that physical maturation leads infants to attain motor milestones in stages,
at roughly the same age, in the same way, and in a steady progression. It has shown
instead that individual children acquire skills at different ages and in different
ways, and that their development entails regressions as well as progress (Adolph &
Berger, 2011).
One example of this type of research is a longitudinal study of the develop-
ment of infants’ reaching conducted by Esther Thelen, who, along with her col-
league Linda Smith, was the cofounder of the dynamic-systems approach to
cognitive development. In this particular study, Thelen and colleagues (1993)
repeatedly observed the reaching efforts of four infants during their first year.
Using high-speed motion-capture systems and computer analysis of the infants’
muscle movements, they found that because of individual differences in such
factors as the infants’ physiology, activity level, arousal, motivation, and expe-
rience, each child faced different challenges in his or her attempts to master
reaching. The following observations illustrate some of the complexities these
researchers discovered, including variability in the ages at which infants reach
developmental milestones, their patterns of change, and the differing challenges
they must overcome:
Infants differed dramatically in the ages of the transition (from no reaching to reach-
ing). Whereas Nathan reached first at 12 weeks, Hannah and Justin did not at-
tain this milestone until 20 weeks of age. [In addition,] the infants showed periods
of rapid change, plateaus, and even regressions in performance. . . . There was in
FIGURE 4.11 problem solving often
requires motor skills A major insight of
dynamic-systems theories is that thinking
would be pointless without motor capabili-
ties. In these photos, a 12-month-old is
shown knocking a barrier out of the way
(left frame) and then grasping the edge of a
cloth in order to pull the cloth, string, and
toy toward him (right frame). If the infant
lacked the motor dexterity to grasp the
cloth or the strength to pull in the toy, his
problem-solving processes would have been
fruitless.
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D Y N A M I C – S Y S T E M S T H E O R I E S n 163
Nathan, Justin, and Hannah a rather discontinuous shift to better, less variable per-
formance. . . . Gabriel’s transition to stability was more gradual.
(Thelen & Smith, 1998, pp. 605, 607)
Infants must individually discover the appropriate [reaching] speeds from the back-
ground of their characteristic styles. Gabriel, for example, had to damp down his very
vigorous movements in order to successfully reach, and he did. In contrast, Hannah,
who moved slowly and spent considerable time with her hands flexed near her face,
had to activate her arms more to extend them out in front of her. . . . Reaching is thus
sculpted from ongoing movements of the arms, through a process of modulating what
is in place. . . . As infants become older, their attention becomes more focused, and
their perceptual discrimination improves, and their memories get better, and their
movements become more skilled. A rich, complex, and realistic account of change
must include this dynamic interplay.
(Thelen, 2001, pp. 172, 182)
These descriptions help to convey what is meant by the label “dynamic systems.”
As suggested by the term dynamic, dynamic-systems theories depict development as a
process in which change is the only constant. Whereas some approaches to cognitive
development hypothesize that development entails long periods of relatively stable
stages or ways of thinking separated by relatively brief transition periods, dynamic-
systems theories propose that at all points in development, thought and action change
from moment to moment in response to the current situation, the child’s immediate
past history, and the child’s longer-term history of actions in related situations. Thus,
Thelen and Smith (1998) noted that the development of reaching included regres-
sions as well as improvements, and Thelen (2001) described how differences in Han-
nah’s and Gabriel’s early reaches influenced their later paths to skilled reaching.
As suggested by the second term in the label, dynamic-systems theories depict
each child as a well-integrated system, in which many subsystems—perception, ac-
tion, attention, memory, language, social interaction, and so on—work together to
determine behavior. For example, success on tasks viewed as measures of conceptual
understanding, such as object permanence, is influenced by perception, attention,
motor skills, and a host of other factors (Smith et al., 1999). The assumptions that
development is dynamic and that it functions as an organized system are central to
the theory’s perspective on children’s nature.
View of Children’s Nature
Dynamic-systems theories are the newest of the four types of theories discussed in
this chapter, and their view of children’s nature incorporates influences from each of
the others. Like Piaget’s theory, dynamic-systems theories emphasize children’s in-
nate motivation to explore the environment; like information-processing theories,
they emphasize precise analyses of problem-solving activity; and like sociocultural
theories, they emphasize the formative influence of other people. These similari-
ties to other theories, as well as the differences from them, are evident in dynamic-
systems theories’ emphasis on motivation and the role of action.
Motivators of Development
To a greater extent than any of the other theories except Piaget’s, dynamic- systems
theories emphasize that from infancy onward, children are strongly motivated to
learn about the world around them and to explore and expand their own capabilities

164 n ChApTer 4 THEORIES OF COGNITIVE DEVELOPMENT
(von Hofsten, 2007). This motivation to explore and learn is clearly apparent in
the fact that children persist in practicing new skills even when they possess well-
practiced skills that are more efficient. Thus, toddlers persist in their first unsteady
efforts to walk, despite the fact that crawling would get them where they want to
go more quickly and without the risk of falling (Adolph & Berger, 2011).
Like sociocultural approaches, but unlike Piagetian theory, dynamic-systems
theories emphasize infants’ interest in the social world as a crucial motivator of de-
velopment. As noted in our discussion of the active child in Chapter 1, even new-
borns prefer attending to the sounds, movements, and features of the human face
over almost any alternative stimuli. By 10 to 12 months of age, infants’ interest in
the social world is readily apparent in the emergence of intersubjectivity (page 159),
as infants look to where the people interacting with them are looking and direct the
attention of others to things they themselves find interesting (Deák, Flom, & Pick,
2000; von Hofsten, Dahlström, & Fredricksson, 2005). Dynamic-systems theo-
rists have emphasized that observing other people, imitating their actions, and at-
tracting their attention are all potent motivators of development (Fischer & Bidell,
2006; von Hofsten, 2007).
The Centrality of Action
Dynamic-systems theories are unique in their pervasive emphasis on how children’s
specific actions shape their development. Piaget’s theory asserts the role of actions
during infancy, but dynamic-systems theories emphasize that actions contribute to
development throughout life. This focus on the developmental role
of action has led to a number of interesting discoveries. For example,
infants’ own reaching for objects helps them infer the goals of other
people’s reaches; infants who can skillfully reach are more likely to
look at the probable target of another person’s reaching just after the
other person’s reach begins (von Hofsten, 2007). Another example of
infants’ learning from actions comes from research in which infants
were outfitted with Velcro mittens that enabled them to “grab” and
explore Velcro-covered objects that they otherwise could not have
picked up. After 2 weeks of grabbing the Velcro-covered objects with
the Velcro-covered mittens, infants showed greater ability to grab
and explore ordinary objects without the mittens than did other in-
fants of the same ages (Needham, Barrett, & Peterman, 2002).
The ways in which children’s actions shape their development
extend well beyond reaching and grasping in infancy. Actions influ-
ence categorization: in one study, encouraging children to move an
object up and down led to their categorizing it as one of a group of
objects that were easiest to move in that way, whereas encouraging
children to move the same object from side to side led them to categorize it as one
of a group of objects that were easiest to move in that way (Smith, 2005). Actions
also affect vocabulary acquisition and generalization (Gershkoff-Stowe, Connell, &
Smith, 2006; Samuelson & Horst, 2008): for example, experimental manipulations
that lead children to state an incorrect name for an object impair the child’s future
attempts to learn the object’s correct name. In addition, actions shape memory, as
demonstrated by research in which children’s past attempts to locate and dig up
objects they had earlier seen being hidden in a sandbox altered their recall of the
objects’ new location after they had seen them being re-hidden. That is, the child’s
new searches tend to be in-between the past and present locations, as if the new
reaching with Velcro-covered mittens for
Velcro-covered objects improved infants’
later ability to grab and explore ordinary
objects without the mittens.
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D Y N A M I C – S Y S T E M S T H E O R I E S n 165
searches involved a compromise between memories of the new hiding place and of
the location where he or she had originally looked (Schutte, Spencer, & Schöner,
2003; Zelazo, Reznick, & Spinazzola, 1998). Thus, just as thinking shapes actions,
actions shape thinking.
Central Development Issues
Two developmental issues that are especially prominent in dynamic-systems theo-
ries are how the cognitive system organizes itself and how it changes.
Self-Organization
Dynamic-systems theories view development as a process of self-organization that
involves bringing together and integrating attention, memory, emotions, and ac-
tions as needed to adapt to a continuously changing environment (Spencer et al.,
2006). The organizational process is sometimes called soft assembly, because the
components and their organization change from moment to moment and situation
to situation, rather than being governed by rigid stages that are consistently applied
across time and situations.
The types of research to which this perspective leads are illustrated particularly
well by certain studies of the A-not-B error that 8- to 12-month-olds typically
make in Piaget’s classic object-permanence task. As noted earlier, this error involves
infants’ searching for a toy where they had previously found it (location A), rather
than where they last saw it being hidden (location B). Piaget (1954) explained the
A-not-B error by hypothesizing that before their 1st birthday, infants lack a clear
concept of the permanent existence of objects.
In contrast, viewing the A-not-B error from a dynamic-systems perspective sug-
gested that many factors other than conceptual understanding influence perfor-
mance on the object-permanence task. In particular, Smith and colleagues (1999)
argued that babies’ previous reaching toward location A produces a habit of reach-
ing there, which influences their behavior when the object is subsequently hidden
at location B. On the basis of this premise, the researchers made several predic-
tions that were later borne out. One was that the more often babies had found an
object by reaching to one location, the more likely they would be to reach there
again when the object was hidden at a different location. Also supported was the
prediction that increasing the memory demands of the task by not allowing infants
to search for the object for 3 seconds after it was hidden at the B location would
increase the likelihood of infants’ reaching to location A (Clearfield et al., 2009).
The reasoning here was that the strength of the new memory would fade rapidly
relative to the fading of the habit of reaching to the previous hiding place. The
dynamic-systems perspective also suggested that infants’ attention would influence
their object-permanence performance. Consistent with this view, manipulating
infants’ attention by tapping one of the locations just as the infants were about to
reach usually resulted in their reaching to the tapped location, regardless of where
the object was actually hidden.
In perhaps the most striking test of such predictions, researchers demonstrated
that putting small weights on infants’ wrists after the infants had reached to loca-
tion A but before the object was hidden at location B improved object-permanence
performance (Diedrich et al., 2000). The researchers had reasoned that the addi-
tion of the wrist weights would require the infants to use different muscle tensions
and forces than they had previously used to reach for the object and consequently

166 n ChApTer 4 THEORIES OF COGNITIVE DEVELOPMENT
would disrupt the infants’ habit of reaching to location A. Thus, rather than pro-
viding a pure measure of conceptual understanding, infants’ performance on the
object-permanence task appears to reflect the combined influence of the strength
of the habit of reaching to location A, the memory demands of the current task,
the infant’s current focus of attention, and the match between the muscular forces
required to reach in the old and new situations.
How Change Occurs
Dynamic-systems theories posit that changes occur through mechanisms of varia-
tion and selection that are analogous to those that produce biological evolution
(Fischer & Biddell, 2006; Steenbeek & Van Geert, 2008). In this context, varia-
tion refers to the use of different behaviors to pursue the same goal. For example, to
descend a ramp, a toddler will sometimes walk, sometimes crawl, sometimes do a
belly slide, sometimes do a sitting slide feet first, and so on (Adolph, 1997; Adolph
& Berger, 2011). Selection involves increasingly frequent choice of behaviors that
are effective in meeting goals and decreasing reliance on less effective behaviors.
For example, when children first learn to walk, they are too optimistic about being
able to walk down ramps, and often fall, but when they gain a few more months of
walking experience, they more accurately judge the steepness of ramps and whether
they can descend them while remaining upright.
BOX 4.4: applications
EDUCATIONAL APPLICATIONS
OF DYNAMIC-SYSTEMS THEORIES
As noted in Chapter 2, children born prema-
turely with low birth weight are more likely
than other children to encounter develop-
mental difficulties, among them slower emer-
gence and refinement of reaching (Fallang et
al., 2003). These delays in reaching slow
the development of brain areas involved in
reaching (Martin et al., 2004), limiting in-
fants’ ability to explore and learn about ob-
jects (Lobo, Galloway, & Savelsbergh, 2004).
A variety of seemingly reasonable efforts to
improve preterm infants’ reaching, such as
guiding their arms through reaching move-
ments, have yielded discouraging results
(Blauw-Hospers & Hadders-Algra, 2005).
In contrast, a recent intervention based
on dynamic-systems research was quite
successful. This intervention, designed by
Heathcock, Lobo, and Galloway (2008), was
inspired by two findings we have discussed:
(1) the finding by Thelen and colleagues
(1993) that some infants’ slowness to initi-
ate arm activity impedes their development
of reaching, and (2) the finding by Needham
and colleagues (2002) that providing young
infants with experience in reaching for and
grabbing Velcro-patched objects while wear-
ing Velcro-covered mittens improves the
infants’ later ability to reach for and grab
ordinary objects barehanded.
Heathcock, Lobo, and Galloway began
their intervention by requesting that care-
givers of preterm infants in an experimental
group provide the infants with special move-
ment experiences. Specifically, they asked
the caregivers to encourage infants’ arm
movements by (1) tying a bell to the infants’
wrists so that arm movements would make
it ring, presumably motivating further move-
ments, and (2) placing Velcro mittens on
the infants’ hands to allow them to reach for
and grab Velcro-patched toys held in front of
them. The caregivers were asked to do this
at home 5 times per week for 8 weeks.
Caregivers of preterm infants in a control
group were asked to provide their infants
with special social experiences that in-
cluded singing to and talking with the in-
fants on the same intervention schedule as
that of children in the experimental group.
Periodically, the infants in both groups were
brought to the lab to allow project person-
nel to observe their reaching and exploration
under controlled circumstances and during
free play.
As might be expected, the reaching of
preterm infants in both groups improved
over the 8 weeks of the study. However,
the infants in the experimental group im-
proved to a greater degree. They more often
touched toys that were held in front of them,
and more often did so with the inside rather
than the outside part of their hand, as is
needed for grasping objects. Such interven-
tions may also help preterm infants avoid
other types of cognitive and motor impair-
ments that are partially caused by delayed
development of reaching.

C H A P T E R S U M M A R Y n 167
chapter summary:
Theories of development are important because they pro-
vide a framework for understanding important phenomena,
raise major issues regarding human nature, and motivate
new research. Four major theories of cognitive development
are Piagetian, information-processing, sociocultural, and
dynamic-systems.
Piaget’s Theory
n Among the reasons for the longevity of Piaget’s theory are that
it vividly conveys the flavor of children’s thinking at different
ages, extends across a broad range of ages and content areas,
and provides many fascinating and surprising observations of
children’s thinking.
n Piaget’s theory is often labeled “constructivist,” because it
depicts children as actively constructing knowledge for them-
selves in response to their experience. The theory posits that
children learn through two processes that are present from
birth—assimilation and accommodation—and that the con-
tribution of these processes is balanced through a third pro-
cess, equilibration. These processes produce continuities
across development.
n Piaget’s theory divides cognitive development into four
broad stages: the sensorimotor stage (birth to age 2), the
preoperational stage (ages 2 to 7), the concrete opera-
tional stage (ages 7 to 12), and the formal operational stage
(age 12 and beyond). These stages reflect discontinuities in
development.
n In the sensorimotor stage, infants’ intelligence is expressed
primarily through motor interactions with the environment.
During this period, infants gain understanding of concepts
such as object permanence and become capable of deferred
imitation.
Children’s selection among alternative approaches reflects several influences.
Most important is the relative success of each approach in meeting a particular
goal: as children gain experience, they increasingly rely on approaches that pro-
duce desired outcomes. Another important consideration is efficiency: children
increasingly choose approaches that meet goals more quickly or with less effort
than do other approaches. A third consideration is novelty, the lure and challenge
of trying something new. Children sometimes choose new approaches that are
no more efficient, or even less efficient, than an established alternative but that
have the potential to become more efficient. For example, when they first learn
the memory strategy of rehearsal, it does not improve their memory, but they use
it anyway, and eventually it does improve their recall of rehearsed information
(Miller & Seier, 1994). Such a novelty preference tends to be adaptive, because
with practice, a strategy that is initially less efficient than existing approaches
often becomes more efficient (Wittmann et al., 2008). As discussed in Box 4.4,
the insights of dynamic-systems theories have led to useful applications as well
as theoretical progress.
review:
Dynamic-systems theories view children as ever-changing, well-integrated organisms that
combine perception, action, attention, memory, language, and social influences to produce
actions that satisfy goals. From this perspective, children’s actions are shaped by both their
remote and recent history, their current physical capabilities, and their immediate physi-
cal and social environment. The actions, in turn, are viewed as shaping the development
of categorization, conceptual understanding, memory, language, and other capabilities.
Dynamic-systems theories are unique in their emphasis on how children’s actions shape their
development, as well as in the range of developmental influences they consider with regard
to particular capabilities.

168 n ChApTer 4 THEORIES OF COGNITIVE DEVELOPMENT
n In the preoperational stage, children become able to rep-
resent their experiences in language, mental imagery, and
thought, but because of cognitive limitations such as egocen-
trism and centration, they have difficulty solving many prob-
lems, including Piaget’s various tests of conservation and tasks
related to taking the perspective of others.
n In the concrete operational stage, children become able to
reason logically about concrete objects and events but have dif-
ficulty reasoning in purely abstract terms and in succeeding on
tasks requiring hypothetical thinking, such as the pendulum
problem.
n In the formal operational stage, children gain the cognitive
capabilities of hypothetical thinking.
n Four weaknesses of Piaget’s theory are that it depicts children’s
thinking as being more consistent than it is, underestimates
infants’ and young children’s cognitive competence, understates
the contribution of the social world to cognitive development,
and only vaguely describes the mechanisms that give rise to
thinking and cognitive growth.
Information-Processing Theories
n Information-processing theories focus on the specific mental
processes that underlie children’s thinking. Even in infancy,
children are seen as actively pursuing goals, encountering pro-
cessing limits, and devising strategies that allow them to sur-
mount the processing limits and attain the goals.
n The memory system includes working memory, long-term
memory, and executive functioning.
n Working memory is a system for actively attending to, gath-
ering, maintaining, storing, and processing information.
n Long-term memory is the enduring knowledge accumulated
over a lifetime.
n Executive functioning is crucial for controlling thought and
action, develops greatly during the preschool and early ele-
mentary school years, and is related to later academic achieve-
ment and occupational success.
n The development of memory and learning in large part reflects
improvements in basic processes, strategies, and content
knowledge.
n Basic cognitive processes allow infants to learn and remember
from birth onward. Among the most important basic processes
are association, recognition, generalization, and encoding.
n The use of strategies enhances learning and memory beyond
the level that basic processes alone could provide. Rehearsal
and selective attention are two important strategies.
n Increasing content knowledge enhances memory and learning
of all types of information.
n One important contributor to the growth of problem solving is
the development of planning.
Sociocultural Theories
n Starting with Vygotsky’s theory, sociocultural theories have
focused on the way that the social world molds development.
These theories emphasize that development is shaped not only
by interactions with other people and the skills learned from
them, but also by the artifacts with which children interact and
the beliefs, values, and traditions of the larger society.
n Sociocultural theories view humans as differing from other
animals in their propensity to teach and their ability to learn
from teaching.
n Establishing intersubjectivity between people through joint
attention is essential to learning.
n Sociocultural theories describe people as learning through
guided participation and social scaffolding, in which others
who are more knowledgeable support the learner’s efforts.
Dynamic-Systems Theories
n Dynamic-systems theories view change as the one constant
in development. Rather than depicting development as being
organized into long periods of stability and brief periods of
dramatic change, these theories propose that there is no period
in which substantial change is not occurring.
n These theories also view each person as a unified system that,
in order to meet goals, integrates perception, action, catego-
rization, motivation, memory, language, conceptual under-
standing, and knowledge of the physical and social worlds.
n Dynamic-systems theories view development as a self-
organizing process that brings together components as needed
to adapt to a continuously changing environment.
n Attaining goals requires action as well as thought. Thought
shapes action, but action also shapes thought.
n Just as variation and selection produce biological evolution,
they also produce cognitive development.
Critical Thinking Questions
1. Piaget’s theory has been prominent for more than 80 years.
Do you think it will continue to be prominent for the next 20
years as well? Why or why not?
2. Do you think that the term egocentric is a good description of
preschoolers’ overall way of seeing the world? On the basis
of what you learned in this chapter and your own experience,
explain your answer and indicate in what ways preschoolers
are egocentric and in what ways they are not.
3. Information-processing analyses tend to be more specific
about cognitive processes than are analyses generated by

C H A P T E R S U M M A R Y n 169
other theories. Do you see this specificity as an advantage or
a disadvantage? Why?
4. Do new behaviors, like new species, grow out of the pro-
cesses of variation and selection, as depicted within dynamic-
systems theories?
5. Imagine that you are trying to help a 6-year-old learn a skill
that you possess. Using the ideas of guided participation
and social scaffolding, describe how you might go about
this task.
6. Dynamic-systems theories reflect influences of each of the
other theories reviewed in this chapter. Which theoretical
influence do you think is strongest: Piagetian, information-
processing, or sociocultural? Explain your reasoning.
Key Terms
A-not-B error, p. 136
accommodation, p. 133
assimilation, p. 133
autobiographical memories, p. 160
basic processes, p. 150
centration, p. 139
concrete operational stage, p. 135
conservation concept, p. 139
cultural tools, p. 156
deferred imitation, p. 137
dynamic-systems theories, p. 161
egocentrism, p. 138
encoding, p. 150
equilibration, p. 133
formal operational stage, p. 135
guided participation, p. 155
information-processing theories, p. 145
intersubjectivity, p. 159
joint attention, p. 159
long-term memory, p. 148
object permanence, p. 136
overlapping-waves theory, p. 152
preoperational stage, p. 135
private speech, p. 157
problem solving, p. 146
rehearsal, p. 151
selective attention, p. 151
sensorimotor stage, p. 135
social scaffolding, p. 159
sociocultural theories, p. 155
symbolic representation, p. 138
task analysis, p. 146
working memory, p. 147

170
M A RY S T E V E N S O N C A S S AT T, Mother and Child, 1900
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chapter 5:
Seeing, Thinking, and
Doing in Infancy
n Perception
Vision
Box 5.1: A Closer Look Infants’ Face Perception
Auditory Perception
Box 5.2: A Closer Look Picture Perception
Taste and Smell
Touch
Intermodal Perception
Review
n Motor Development
Reflexes
Motor Milestones
Current Views of Motor Development
Box 5.3: A Closer Look “The Case of the
Disappearing Reflex”
The Expanding World of the Infant
Box 5.4: Applications A Recent Secular Change in
Motor Development
Box 5.5: A Closer Look “Gangway—I’m Coming Down”
Review
n Learning
Habituation
Perceptual Learning
Statistical Learning
Classical Conditioning
Instrumental Conditioning
Observational Learning/Imitation
Rational Learning
Review
n Cognition
Object Knowledge
Physical Knowledge
Social Knowledge
Looking Ahead
Review
n Chapter Summary

172
F
our-month-old Benjamin, perched on the kitchen counter in his infant seat,
is watching his parents wash the dinner dishes. What he observes includes
two people who move on their own, as well as a variety of glass, ceramic, and
metal objects of differing sizes and shapes that move only when picked up
and manipulated by the people. Other elements of the scene never move. As
the people go about their task, distinctive sounds emanate from their moving lips,
while different sounds occur as they deposit cutlery, skillets, glasses, and sponges on
the kitchen counter. At one point, Benjamin sees a cup completely disappear from
view when his father places it on the counter behind a cooking pot; it reappears a
moment later when the pot is moved. He also sees objects disappear as they pass
through the suds and into the water, but he never sees one object pass through an-
other. The objects that are placed on the counter stay put, until Benjamin’s father
puts a crystal goblet on the counter with more than half of its base hanging over
the counter’s edge. The crashing sound that follows startles all three people in the
room, and Benjamin is further startled when the two adults begin emitting sharp,
loud sounds toward one another, quite unlike the soft, pleasant sounds they had
been producing before. When Benjamin begins crying in response, the adults rush
to him, patting him and making soft, especially pleasant sounds to him.
This example, to which we will return throughout the chapter, illustrates the enor-
mous amount of information that is available for an infant to observe and learn from
in even the most everyday situations. In learning about the world, Benjamin, like
most infants, avidly explores everything and everyone around him, using every tool
he has: he gathers information by looking and listening, as well as by tasting, smell-
ing, and touching. His explorations will gradually expand as he becomes capable first
of reaching for objects and then of manipulating them, making it possible for him
to discover more about them. When he starts to move around under his own power,
even more of the world will become available to him, including
things his parents would prefer that he not investigate, such as elec-
trical outlets and kitty litter. Never will Benjamin explore so vora-
ciously or learn so rapidly as in the first few years of his young life.
In this chapter, we discuss development in four closely related
areas: perception, action, learning, and cognition. Our discussion
focuses primarily on infancy. One reason for concentrating on this
period is that extremely rapid change occurs in all four areas dur-
ing the first two years of a child’s life. A second reason is the fact
that infant development in these four domains is particularly inter-
twined: the minirevolutions that transform infants’ behavior and
experience in one domain lead to minirevolutions in others. For
example, the dramatic improvements in visual abilities that occur in
their first few months enable infants to see more of the people and
objects around them, thereby greatly increasing the opportunities
they have to learn new information.
A third reason for concentrating on infancy in this chapter is
the fact that the majority of recent research on perceptual and
motor development has been done with infants and young chil-
dren. There is also a large body of fascinating research on learning
and cognition in the first few years. We will review some of this
research here and cover subsequent development in these areas
in later chapters. A final reason for focusing on infants in this
Themes
n Nature and Nurture
n The Active Child
n Continuity/Discontinuity
n Mechanisms of Change
n The Sociocultural Context
n Individual Differences
Like Benjamin, this infant will take in a
great deal of perceptual information just
observing his father washing dishes.
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P E R C E P T I O N n 173
chapter is that the methods used to investigate infants’ development in these four
domains are, of necessity, quite different from those that researchers are able to use
to study older children.
Our examination of key developments in infancy will feature several enduring
themes. The active child theme is vividly embodied by infants’ eager exploration of
their environment. Continuity/discontinuity arises repeatedly in research that ad-
dresses the relation between behavior in infancy and subsequent development. In
some sections, the mechanisms of change theme is also prominent, as we explore the
role that variability and selection play in infants’ development. In our discussion
of early motor development, we will examine contributions made by the sociocul-
tural context.
Underlying much of this chapter, of course, is the theme of nature and nurture.
For at least 2,000 years, an often-contentious debate has existed between those
philosophers and scientists who have emphasized innate knowledge in account-
ing for human development and those who have emphasized learning (Spelke &
Newport, 1998). The desire to shed light on this age-old debate is one reason that
an enormous amount of research has been conducted with infants over the past few
decades. As you will see, these discoveries have revealed that infant development is
even more complicated and remarkable than previously suspected.
Perception
Parents of new babies cannot help wondering what their children experience—
how much they can see, how well they can hear, whether they connect sight and
sound (as in our opening vignette), and so on. William James, one of the first psy-
chologists, believed that the world of the newborn is a “big blooming, buzzing
confusion.” Because of remarkable advances in the study of early sensation and per-
ception, modern researchers do not share his view. They have demonstrated that in-
fants come into the world with all their sensory systems functioning to some degree
and that subsequent development occurs at a very rapid pace. Sensation refers to
the processing of basic information from the external world by the sensory recep-
tors in the sense organs (eyes, ears, skin, and so forth) and the brain. Perception is
the process of organizing and interpreting sensory information about the objects,
events, and spatial layout of the world around us. In our opening example, sensation
involved light and sound waves activating receptors in Benjamin’s eyes, ears, and
brain; an instance of perception involved, for example, his experiencing the visual
and auditory stimulation provided by the crashing goblet as a single coherent event.
In this section, we devote the most attention to vision, both because of its fun-
damental importance to humans and because so much more research has been
conducted on vision than on the other senses. We will also discuss hearing and, to
a lesser degree, taste, smell, and touch, as well as the coordination between these
multiple sensory modalities. Although these abilities often seem commonplace to
us as adults, they are actually some of the most remarkable achievements attained
during the first year of life.
Vision
Humans rely more heavily on vision than most species do: roughly 40% to 50% of
our mature cerebral cortex is involved in visual processing (Kellman & Arterberry,
2006). As recently as a few decades ago, it was generally assumed that newborns’
sensation n the processing of basic
information from the external world by
the sensory receptors in the sense organs
(eyes, ears, skin, etc.) and brain
perception n the process of organizing
and interpreting sensory information

174 n chapter 5 SEEING, THINKING, AND DOING IN INFANCY
vision was so poor as to be barely functional. However, once researchers started
carefully studying the looking behavior of newborns and young infants, they dis-
covered that this assumption was incorrect. In fact, newborns begin visually explor-
ing the world minutes after leaving the womb. They scan the environment, and
when their gaze encounters a person or object, they pause to look at it. Although
newborns do not see as clearly as adults do, their vision improves extremely rapidly
in their first months. And as you will learn, recent studies have revealed that despite
their immature visual systems, even the youngest infants have some surprisingly
sophisticated visual abilities.
The evidence that enables us to say this so confidently was made possible by
the invention of a variety of ingenious research methods. Because young infants
are unable to understand and respond to instructions, investigations of infant abil-
ities required researchers to devise methods that are quite different from those
used with older children and adults. The first breakthrough was achieved with the
preferential-looking technique, a method for studying visual attention in infants.
In this technique, pioneered by Robert Fantz (1961), two different visual stimuli are
typically displayed on side-by-side screens. If an infant looks longer at one of the two
stimuli, the researcher can infer that the baby is able to discriminate between them
and has a preference for one over the other. Fantz established that newborns, just
like everyone else, would rather look at something than at nothing. When a pattern
of any sort—black and white stripes, newsprint, a bull’s-eye, a schematic face—was
paired with a plain surface, the infants preferred (i.e., looked longer at) the pattern.
Another method that is used to study sensory and perceptual development in
infants is habituation, which you encountered in Chapter 2 as a research tool used
in studying fetal development. This procedure involves repeatedly presenting an
infant with a particular stimulus until the infant’s response to it habituates, that is,
declines. Then a novel stimulus is presented. If the infant’s response increases, the
researcher infers that the baby can discriminate between the old and new stimu-
lus. Despite their simplicity, habituation and preferential-looking procedures have
turned out to be enormously powerful for studying infants’ perception and under-
standing of the world.
Visual Acuity
The preferential-looking method enables researchers (and eye-care professionals)
to assess infants’ visual acuity, that is, to determine how clearly they can see. This
method builds on research showing that infants who can see the difference be-
tween a simple pattern and a solid gray field consistently prefer to
look at the pattern (Figure 5.1). By varying the patterns and as-
sessing infants’ preferences, researchers have learned a great deal
about not only infants’ early visual abilities but also about their
looking preferences. For example, young infants generally pre-
fer to look at patterns of high visual contrast—such as a black-
and-white checkerboard (Banks & Dannemiller, 1987). This is
because young infants have poor contrast sensitivity: they can
detect a pattern only when it is composed of highly contrasting
elements.
One reason for this poor contrast sensitivity is the immaturity
of infants’ cones, the light-sensitive neurons that are highly con-
centrated in the fovea (the central region of the retina) and are in-
volved in seeing fine detail and color. In infancy, the cones have a
preferential-looking technique n a
method for studying visual attention in
infants that involves showing infants two
patterns or two objects at a time to see if
the infants have a preference for one over
the other
visual acuity n the sharpness of visual
discrimination
contrast sensitivity n the ability to
detect differences in light and dark areas
in a visual pattern
cones n the light-sensitive neurons that
are highly concentrated in the fovea (the
central region of the retina)
FIGURE 5.1 testing infants’ visual
acuity paddles like those depicted here
can be used to assess young infants’ visual
acuity. two paddles are shown to the infant
simultaneously, one with stripes and one in
plain gray. If the infant can detect the con-
trast difference between the black and white
stripes, the infant’s gaze should, because
of infants’ preference for a patterned visual
field over a plain one, become oriented
toward the striped paddle. the ophthal-
mologist or researcher presents the infant
a succession of paddles with increasingly
narrow stripes, with increasingly narrow gaps
between them, until the infant can no longer
distinguish between the striped paddle and
the plain gray one. the degree of grating on
the last paddle discriminated provides an
indication of the infant’s visual acuity.
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P E R C E P T I O N n 175
different size and shape and are spaced farther apart than
in adulthood (Kellman & Arterberry, 2006). As a conse-
quence, newborns’ cones catch only 2% of the light strik-
ing the fovea, compared with 65% for adults (Banks &
Shannon, 1993). This is partly why in their first month,
babies have only about 20/120 vision (a level of acuity
that would enable an adult to read the large E at the top
of a standard eye chart). Subsequently, visual acuity de-
velops so rapidly that by 8 months of age, infants’ vision
approaches that of adults, with full adult acuity present
by around 6 years of age (Kellman & Arterberry, 2006).
Another restriction on young infants’ visual experi-
ence is that, for the first month or so, they do not share
adults’ experience of a richly colorful world. At best, they
can distinguish some shades from white (Adams, 1995).
By 2 or 3 months of age, infants’ color vision is simi-
lar to that of adults (Kellman & Arterberry, 2006). Indeed, it is similar to the ex-
tent that 4- and 5-month-olds prefer (look longest at) the same basic colors that
adults rate as most pleasant—red and blue (Bornstein, 1975). They also perceive
the boundaries between colors in more or less the same way as adults do: they re-
spond equivalently to two shades that adults label as the same color (e.g., “blue”),
but they discriminate between two shades that adults refer to with different color
names (e.g., “blue” and “green”) (Bornstein, Kessen, & Weiskopf, 1976).
Visual Scanning
As noted, newborns start visually scanning the environment right away. From the
beginning, they are attracted to moving stimuli. However, they have trouble track-
ing these stimuli because their eye movements are jerky and often do not stay with
whatever they are trying to visually follow. Not until 2 or 3 months of age are in-
fants able to track moving objects smoothly, and then they are able to do so only if
an object is moving slowly (Aslin, 1981). This developmental achievement appears
to be less a function of visual experience than of maturation. Preterm infants, whose
neural and perceptual systems are immature, develop smooth visual tracking later
than full-term infants do (Strand-Brodd et al., 2011).
Another limitation on young infants’ visual experience of the world (and there-
fore on what they can learn) is that their visual scanning is restricted. With a simple
figure like a triangle, infants younger than 2 months old look almost exclusively
at one corner. With more complex shapes, they tend to scan only the outer edges
(Haith, Bergman, & Moore, 1977; Milewski, 1976). Thus, as Figure 5.2 shows,
when 1-month-olds look at a line drawing of a face, they tend to fixate on the
perimeter—on the hairline or chin, where there is relatively high contrast with the
background. By 2 months of age, infants scan much more broadly, enabling them
to pay attention to both overall shape and inner details (see Box 5.1).
Pattern Perception
Accurate visual perception of the world requires more than acuity and systematic
scanning; it also requires analyzing and integrating the separate elements of a visual
display into a coherent pattern. To perceive the face in Figure 5.2, as 2-month-olds
apparently do, they must integrate the separate elements.
the blurred image on the right is roughly
what a 1-month-old infant would perceive.
the infant’s relatively low level of visual
acuity leads some features of the image to
pop out—those with higher contrast (e.g.,
the woman’s eyes and hairline).
B
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IN
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T
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K
Start
Start
Finish
Finish
(a) (b)
FIGURE 5.2 Visual scanning the lines
superimposed on these face pictures show
age differences in where two babies fixated
on the images. (a) a 1-month-old looked pri-
marily at the outer contour of the face and
head, with a few fixations of the eyes. (b) a
2-month-old fixated primarily on the internal
features of the face, especially the eyes and
mouth. (From Maurer & Salapatek, 1976)

176 n chapter 5 SEEING, THINKING, AND DOING IN INFANCY
BOX 5.1: a closer look
INFANTS’ FACE PERCEPTION
A particularly fascinating aspect of infant
perception has to do with the reaction of
human infants to that most social of all
stimuli—the human face. As we have noted,
infants are drawn to faces from birth, lead-
ing researchers to ask what initially attracts
their attention. The answer, it seems, is a
When presented with each of these three pairs of stimuli, newborns look longer at the image in
the left-hand column, revealing a general preference for top-heavy stimuli that contributes to
their preference for human faces (Macchi cassia et al., 2004; Simion et al., 2002). Notice that
this simple preference is all that is needed to result in newborns spending more time looking at
their mother’s face than at anything else. By 3 months of age, however, infants no longer dis-
criminate between the faces in the middle pair of pictures, suggesting that their visual attention
is no longer guided by a general top-heavy bias (Macchi cassia et al., 2006).©
2
0
0
6
E
LS
E
V
IE
R
Upright
face
Inverted
face
Upright
face
Scrambled
Top-heavy
Scrambled
Top-heavy
Scrambled
Bottom-heavy
readily discriminate between two human
faces. However, adults and 9-month-olds
have a great deal of difficulty telling the dif-
ference between one monkey face and an-
other (Pascalis, de Haan, & Nelson, 2002).
Surprisingly, 6-month-olds are just as good
at discriminating between monkey faces as
they are at discriminating between human
faces.
The researchers concluded that the
9-month-olds and adults rely on a detailed
prototype of the human face to discrimi-
nate between people, but this prototype
does not help them tell the difference be-
tween monkeys. The fact that the 6-month-
olds discriminated among monkey faces
just as well as they discriminated among
human faces suggests that these younger
infants have not yet developed a tightly or-
ganized prototype for human faces. While
6-month-olds are certainly knowledgeable
about faces, they do not yet privilege the
details of human faces over the details of
monkey faces.
Consistent with this account is research
showing effects of experience on face rec-
ognition. In one study, from the age of 6
months to 9 months, infants were shown a
set of pictures of monkey faces on a regu-
lar schedule for 1 to 2 minutes. When they
were tested at 9 months of age, they dem-
onstrated that they had retained their ability
to distinguish between monkey faces, unlike
a control group of 9-month-olds who had not
had the exposure to monkey faces (Pascalis
et al., 2005).
Another type of experience that shapes
infant face perception is exposure to
very general bias toward configurations with
more elements in the upper half than in the
lower half—something that characterizes
all human faces (Macchi Cassia, Turati, &
Simion, 2004; Simion et al., 2002) (see
the images in the first column). Evidence in
support of a general bias to attend to face-
like stimuli comes from studies showing that
newborn humans are equally interested in
human faces and monkey faces—as long as
they are presented right-side up (Di Giorgio
et al., 2012).
From paying lots of attention to faces,
infants very quickly come to recognize and
prefer their own mother’s face. After expo-
sure to Mom over the first few days after
birth, infants look longer at her face than at
the face of another woman, even when con-
trolling for olfactory cues (a necessary step
because, as discussed in Chapter 2, new-
borns are highly attuned to their mother’s
scent) (Bushnell, Sai, & Mullin, 2011). Over
the ensuing months, infants develop a pref-
erence for faces depicting the gender of the
caregiver they see most often, whether fe-
male or male (Quinn, et al., 2002).
With exposure to many different faces
over their first months, infants gradually
develop a well-organized perceptual proto-
type for human faces. The formation of this
detailed face prototype then facilitates dis-
crimination between different faces. Evi-
dence for the formation of a general face
prototype in the first year comes from an in-
triguing study of infants’ and adults’ ability
to discriminate between individual human
faces and individual monkey faces. Adults,
9-month-olds, and 6-month-olds can all

P E R C E P T I O N n 177
individuals of different races. The other race
effect (ORE) is a well-established finding,
initially observed in adults, in which indi-
viduals find it easier to distinguish between
faces of individuals from their own racial
group than between faces from other ra-
cial groups. It was later determined that the
ORE emerges in infancy. Whereas newborns
show no preference for own-race faces over
other-race faces, 3-month-old White, Afri-
can, and Chinese infants prefer own-race
faces (Kelly, Liu et al., 2007; Kelly et al.,
2005). Over the second half of the first
year, infants’ face processing continues to
become more specialized, as shown by the
emergence of the ORE; by 9 months of age,
infants have more difficulty discriminating
between other-race faces than between own-
race faces (Kelly, Quinn et al., 2007; Kelly
et al., 2009).
What drives these effects is not the infant’s
own race per se but, rather, the features of
individuals in the infant’s immediate envi-
ronment. For example, 3-month-old African
emigrants to Israel who were exposed to both
African and White caregivers showed equal
interest in African and White faces (Bar-Haim
et al., 2006). Further evidence of effects of
visual experience on face perception comes
from a study suggesting that the facial-
scanning abilities of biracial infants—who are
exposed to the facial features characteristic
of two races in the home—are more mature
than those of monoracial infants (Gaither,
Pauker, & Johnson, 2012).
One of the most intriguing aspects of in-
fants’ facial preferences is the fact that,
along with all the rest of us, babies like
a pretty face. From birth, infants look lon-
ger at faces that are judged by adults to
be highly attractive than at faces judged
to be less appealing (Langlois et al.,
1991; Langlois et al., 1987; Rubenstein,
Kalakanis, & Langlois, 1999; Slater et al.,
1998, 2000).
Older infants’ preference for prettiness,
like adults’, also affects their behavior to-
ward real people. This was demonstrated
in a study in which 12-month-olds inter-
acted with a woman whose face was either
very attractive or very unattractive (Langlois,
Roggman, & Rieser-Danner, 1990). The first
key feature of this study was that the attrac-
tive woman and the unattractive woman were
one and the same! This duality of appearance
was achieved through the use of extremely
natural-looking professional masks that were
applied before the woman interacted with
the infants. On a given day, the young woman
who would test the babies emerged from her
makeup session looking either fabulous or
not so fabulous, depending on which mask
she was wearing. The masks conformed to
what adults judge to be a very attractive face
and a relatively unattractive one.
When interacting with the woman, in-
fant participants behaved differently as a
function of which mask she was wearing.
They were more positive, became more in-
volved in play, and were less likely to with-
draw when she was wearing the attractive
mask than when she had on the unattract-
ive one. This study was particularly well
designed because the young woman never
knew on any given day which mask she had
on. Thus, the children’s behavior could not
have been cued by her behavior; it could
only have been due to her pretty or homely
appearance.
Do the photographs of the men show the same person or different people? how
about the two monkey photos? as an adult human, you no doubt can tell the two
men apart quite easily, but you may still not be sure whether the two monkey
photos are of different individuals. (they are.)
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178 n chapter 5 SEEING, THINKING, AND DOING IN INFANCY
A striking demonstration of integrative pattern perception in infancy comes
from research using the stimulus shown in Figure 5.3. When you look at it, you
no doubt perceive a square, even though no square actually exists. This perception
of subjective contour results from your active integration of the separate elements
in the stimulus into a single pattern. If you simply looked at the individual shapes
in turn, no square would pop out. Like you, 7-month-olds perceive the subjective
square in Figure 5.3 (Bertenthal, Campos, & Haith, 1980), indicating that they
integrate the separate elements to perceive the whole. Even newborns can do so if
motion cues are added to the display, such as arranging it so that the illusory square
appears to move back and forth (Valenza & Bulf, 2007).
Infants are also able to perceive coherence among moving elements. In research
by Bertenthal and his colleagues (Bertenthal, 1993; Bertenthal, Proffitt, & Kramer,
1987), infants watched a film of moving points of light. Adults who watch this
film immediately and confidently identify what they see as a person walking; the
moving lights appear to be (and are) attached to the major joints and head of an
adult. Five-month-olds apparently see the same thing; they look longer at the
point-light displays that suggest human movement than at ones that do not. As
with the research on newborns’ response to the illusory square in Figure 5.3, recent
studies have confirmed that even newborns show a preference for a moving-lights
depiction of biological motion over one of nonbiological motion (Bardi, Regolin,
& Simion, 2011). Taken together, these results suggest that despite their limited
acuity and lack of visual experience, newborns are already attentive to the configu-
rations of elements in their visual world.
Object Perception
One of the most remarkable things about our perception of objects in the world
around us is how stable the world appears to be. When a person approaches or moves
away from us, or slowly turns in a circle, our retinal image of the person changes in
size and shape, but we do not have the impression that the person changes in size
and shape. Instead, we perceive a constant shape and size, a phenomenon known
as perceptual constancy. For a good demonstration of size constancy, look in the
mirror and notice that the image of your face seems to be the normal size of a face.
Then steam up the mirror and trace the outline of your face on the mirror. You will
find that the outline is actually a great deal smaller than your face. But because of
perceptual constancy, you perceive the image in the mirror as being the same size as
any other adult face.
The origin of perceptual constancy was a traditional component
in the debates between empiricists and nativists. Briefly, empiricists
maintain that all knowledge arises from experience, whereas nativists
hold that certain aspects of knowledge are, in fact, innate, or hard-
wired. Thus, empiricists argue that our perception of the constant
size and shape of objects develops as a function of spatially experi-
encing our environment, whereas nativists argue that this perceptual
regularity stems from inherent properties of the nervous system.
The nativist view is supported by evidence of perceptual con-
stancy in newborns and very young infants. In a study of size con-
stancy (Slater, Mattock, & Brown, 1990), newborns were repeatedly
shown either a large or a small cube at varying distances. While the
cube’s actual size remained the same, the size of the retinal image
projected by the cube changed from one trial to the next (see Fig-
ure 5.4). The question was whether the newborns would perceive
FIGURE 5.3 Subjective contour When
you look at this figure, you no doubt see a
square—what is called a subjective contour,
because it does not actually exist on the
page. Seven-month-olds also detect the illu-
sory square. (From Bertenthal et al., 1980)
perceptual constancy n the percep-
tion of objects as being of constant size,
shape, color, etc., in spite of physical dif-
ferences in the retinal image of the object
FIGURE 5.4 If this infant looks longer at
the larger but farther-away cube, researchers
will conclude that the child has size
constancy.
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P E R C E P T I O N n 179
these events as multiple presentations of the same object or as presentations of simi-
lar objects of different sizes.
To answer this question, the researchers subsequently presented the newborns
with the original cube and a second one that was identical except that it was twice
as large. The crucial factor was that the second cube was located twice as far away
as the original one, so it produced the same-size retinal image as the original. The
infants looked longer at the new cube, indicating that they saw it as different in size
from the original one. This, in turn, revealed that they had perceived the multiple
presentations of the original cube as a single object of a constant size, even though
its retinal size varied. Thus, visual experience is not necessary for size constancy
(Granrud, 1987; Slater & Morison, 1985).
Another crucial perceptual ability is object segregation, the perception of the
boundaries between objects. To appreciate the importance of this ability, look around
and try to imagine that you are seeing the scene and the objects in it for the first
time. How can you tell where one object ends and another begins? If the objects are
separated by a gap, the boundaries between the objects are obvious. But what if there
are no visible gaps? Suppose, for example, that as baby Benjamin watches his par-
ents washing dishes, he sees a cup sitting on a saucer. An adult would perceive this
arrangement as two distinct objects, but will Benjamin? Lacking experience with
china, Benjamin may be unsure: the difference in shape suggests two objects, but the
common texture suggests only one. Now suppose that Ben’s mother picks up the cup
to dip it in the suds, leaving the saucer on the table. Will he still be uncertain? No,
because even infants treat the independent motion of cup and saucer (or any objects)
as a signal that they are separate entities. Is this knowledge innate, or do infants ac-
quire it from observing everyday events in their environment?
The importance of motion as a cue indicating the boundaries between objects
was initially demonstrated in a classic experiment by Kellman and Spelke (1983).
First, 4-month-olds were presented with the display shown in Figure 5.5a. This
display could be perceived either as two pieces of a rod moving on each end of a
block of wood or as a single rod moving back and forth behind the block. Impor-
tantly, adults perceive displays of this type the latter way. After habituating to the
display, the infants were shown the two test displays in Figure 5.5b: a whole rod
and a rod broken into two pieces. The investigators reasoned that if the infants, like
adults, assumed that there was a single intact rod moving behind the block during
habituation, they would look longer at the broken rod because that display would
be relatively novel. And that is exactly what the babies did.
What caused the infants to perceive the two rod segments presented during ha-
bituation as parts of a unitary object? The answer is common movement, that is, the
fact that the two segments always moved together in the same direction and at the
same speed. Four-month-olds who saw a display that was the same as the one in
Figure 5.5a, except that the rod was stationary, looked equally long at the two test
displays. In other words, in the absence of common movement, the display was
ambiguous.
Common movement is such a powerful cue that it leads infants to perceive
disparate elements moving together as parts of a unitary object. It does not mat-
ter if the two parts of the object moving behind the block differ in color, texture,
and shape, nor does it make much difference how they move (side to side, up and
down, and so forth) (Kellman & Spelke, 1983; Kellman, Spelke, & Short, 1986).
For infants, common motion may have this effect, in part, because it draws their
attention to the relevant aspects of the scene—the moving pieces rather than the
block (S. P. Johnson et al., 2008). Strikingly, however, even this seemingly very
basic feature of visual perception must be learned. Newborn infants, tested using
(a)
(b)
FIGURE 5.5 Object segregation Infants
who see the combination of elements in (a)
perceive two separate objects, a rod moving
behind a block. after habituating to the dis-
play, they look longer at two rod segments
than at a single rod (b), indicating that they
find the single rod familiar but the two seg-
ments novel. If they first see a display with
no movement, they look equally long at the
two test displays. this result reveals the
importance of movement for object segrega-
tion. (From Kellman & Spelke, 1983)
object segregation n the identification
of separate objects in a visual array

180 n chapter 5 SEEING, THINKING, AND DOING IN INFANCY
displays similar to those described above and shown in Figure 5.5, do not appear
to make use of common motion as a cue to object identity (Slater et al., 1990,
1996). Only at 2 months of age do infants show any evidence that they use com-
mon motion to interpret the occluded rod as a single object (S. P. Johnson & Aslin,
1995). Thus, as powerful a cue as common motion may be, infants must develop
the ability to exploit it.
As they get older, infants use additional sources of information for object seg-
regation, including their general knowledge about the world (Needham, 1997;
Needham & Baillargeon, 1997). Look at the displays shown in Figure 5.6. The
differences in color, shape, and texture between the box and the tube in Figure
5.6a suggest that there are two separate objects, although you cannot really be sure.
However, your knowledge that objects cannot float in midair tells you that Figure
5.6b has to be a single object; that is, the tube must be attached to the box.
Like you, 8-month-olds interpret these two displays differently. When they see
a hand reach in and pull on the tube in Figure 5.6a, they look longer (presumably
they are more surprised) if the box and tube move together than if the tube comes
apart from the box, indicating that they perceive the display as two separate objects.
However, the opposite pattern occurs in Figure 5.6b: now the infants look longer if
the tube alone moves, indicating that they perceive a single object. Follow-up stud-
ies using the displays in Figure 5.6 with younger infants suggest that younger in-
fants (4½-month-olds) exhibit the adultlike interpretation of these displays, but only
when they have been familiarized previously with the box or the tube ( Needham &
Baillargeon, 1998). Thus, it appears that experience with specific objects helps in-
fants to understand their physical properties. We will return to this idea later in this
chapter when we discuss the implications of motor development for infants’ knowl-
edge about objects (particularly with respect to reaching, on page 192).
Depth Perception
To navigate through our environment, we need to know where we are with respect
to the objects and landmarks around us. We use many sorts of depth and distance
cues to tell us whether we can reach the coffee cup on our desk or whether the ap-
proaching car is far enough away that we can safely cross in front of it. From the
beginning, infants are sensitive to some of these cues, and they rapidly become
sensitive to the rest.
One cue that infants are sensitive to very early on is optical expansion, in which
the visual image of an object increases in size as the object comes toward us, oc-
cluding more and more of the background. When an image of an approaching ob-
ject expands symmetrically, we know that the object is headed right for us, and a
sensible response is to duck. Babies cannot duck, but they can blink. Timing this
(a) (b)
FIGURE 5.6 Knowledge and object
segregation (a) It is impossible to know
for sure whether what you see here is one
object or two. (b) Because of your knowledge
about gravity and support, you can be sure
that this figure is a single (albeit very odd)
object. (From Needham, 1997)
optical expansion n a depth cue in
which an object occludes increasingly
more of the background, indicating that
the object is approaching

P E R C E P T I O N n 181
blinking response is critical; if infants blink too soon or too late, they risk having
the oncoming object hit their open eye. If you think about it, though, it’s not at all
obvious how infants would know how to correctly time a blink. Doing so requires
infants to rapidly exploit information present in the visual image looming before
them, including how rapidly the image is expanding and amount of the visual field
taken up by the image. Rather remarkably, infants as young as 1 month blink de-
fensively at an expanding image that appears to be an object heading toward them
(Ball & Tronick, 1971; Náñez & Yonas, 1994; Yonas, 1981). Preterm infants show a
delayed developmental pattern of blinks to looming objects, suggesting that matu-
ration, and not solely postnatal visual experience, is crucial for this developmental
achievement (Kayed, Farstad, & van der Meer, 2008).
Another depth cue that emerges early is due to the simple fact that we have two
eyes. Because of the distance between them, the retinal image of an object at any
instant is never quite the same in both eyes. Consequently, the eyes never send quite
the same signal to the brain—a phenomenon known as binocular disparity. The
closer the object we are looking at, the greater the disparity between the two images;
the farther away the object, the less the disparity. In a process known as stereopsis,
the visual cortex computes the degree of disparity between the eyes’ differing neu-
ral signals and produces the perception of depth. This form of depth perception
emerges quite suddenly at around 4 months of age and is generally complete within
a few weeks (Held, Birch, & Gwiazda, 1980), presumably due to maturation of the
visual cortex.
At around 6 or 7 months of age, infants begin to become sensitive to a variety of
monocular depth cues (so called because they denote depth even if only one eye is
open) (Yonas, Elieff, & Arterberry, 2002). These cues are also known as pictorial
cues, because they can be used to portray depth in pictures. Three of them, includ-
ing relative size, are presented in Figure 5.7.
FIGURE 5.7 pictorial cues this renais-
sance painting contains multiple examples
of pictorial cues. One is interposition—
nearer objects occlude ones farther away.
the convergence of lines in the distance is
another. to appreciate the effectiveness of a
third cue—relative size—compare the actual
size of the man on the steps in the fore-
ground to the actual size of the woman in
the blue dress.EM
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binocular disparity n the difference
between the retinal image of an object in
each eye that results in two slightly dif-
ferent signals being sent to the brain
stereopsis n the process by which
the visual cortex combines the differing
neural signals caused by binocular dis-
parity, resulting in the perception of
depth
monocular depth (or pictorial) cues
n the perceptual cues of depth (such as
relative size and interposition) that can be
perceived by one eye alone

182 n chapter 5 SEEING, THINKING, AND DOING IN INFANCY
In one of the earliest studies of infants’
sensitivity to monocular depth cues, Yonas,
Cleaves, and Pettersen (1978) capitalized on
the fact that infants will reach toward which-
ever of two objects is nearer. The investigators
put a patch over one eye of 5- and 7-month-
olds (so binocular depth information would
not be available) and presented them with
a trapezoidal window with one side consid-
erably longer than the other (Figure 5.8).
(When viewed by an adult with one eye
closed, the window appears to be a standard
rectangular window sitting at an angle with
one side closer to the viewer.) The 7-month-
olds (but not the younger babies) reached toward the longer side, indicating that
they, as you would, perceived it as being nearer, providing evidence that they used
relative size as a cue to depth. (Box 5.2 reviews research on infants’ perception of
pictures.)
Auditory Perception
Another rich source of infants’ information about the world is sound. As we dis-
cussed in Chapter 2, fetuses can hear sufficiently well to learn basic features of their
auditory environment (their mother’s heartbeat, the rhythmic patterns of her native
language, and so forth). At birth, the human auditory system is well developed rela-
tive to the visual system. That said, although the inner ear structures appear to be
mature and adultlike, the conduction of sound through the outer parts of the ear is
inefficient (Keefe et al., 1993). Over the course of infancy, there are vast improve-
ments in sound conduction from the outer and middle ear to the inner ear. Simi-
larly, over the first year, auditory pathways in the brain mature significantly. Taken
together, these developments in the ear and in the brain greatly improve the infant’s
ability to respond to, and learn from, sound.
Other factors add to infants’ auditory improvement. One example involves
auditory localization, the perception of the spatial location of a sound source.
When they hear a sound, newborns tend to turn toward it. However, newborns
and young infants are far worse at determining the spatial location of a sound than
older infants and toddlers are. To localize a sound, listeners rely on differences in
the sounds that arrive at both of their ears: a sound played to their right will ar-
rive at their right ear before reaching their left ear, and will be louder at their right
ear than at their left ear, thereby signaling the direction the sound is coming from.
Young infants may have more difficulty using this information because their heads
are small, and thus the differences in timing and loudness in information arriv-
ing at each ear are smaller for infants than for toddlers and children with larger
heads. Another reason that this information may be difficult for infants to use is
that the development of an auditory spatial map (that is, a mental representation
of how sounds are organized in physical space—right versus left, up versus down)
requires multimodal experiences, through which infants become able to integrate
information from what they hear with information from what they see and touch.
The development of an auditory spatial map must therefore await the improve-
ments in visual and motor skills that emerge later in infancy (Saffran, Werker, &
Werner, 2006).
FIGURE 5.8 Monocular depth cues
this 7-month-old infant is using the mon-
ocular depth cue of relative size. Wearing
an eye patch to take away binocular depth
information, he is reaching to the longer
side of a trapezoidal window. this behavior
indicates that the baby sees it as the nearer,
and hence more readily reachable, side of
a regular rectangular window. (Yonas et al.,
1978)
B
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auditory localization n perception of
the location in space of a sound source

P E R C E P T I O N n 183
A special case of perceptual development
concerns pictures. Paintings, drawings, and
photographs are ubiquitous in modern soci-
eties, and we acquire an enormous amount
of information through them. When can in-
fants perceive and understand these impor-
tant cultural artifacts?
Even young infants perceive pictures in
much the same way that you do. In a classic
study, Hochberg and Brooks (1962) raised
their own infant son with no exposure to
pictures at all: no art or family photos; no
picture books; no patterns on sheets, cloth-
ing, or toys. They even removed the labels
from canned foods. Nevertheless, when
tested at 18 months, the child readily iden-
tified people and objects in photographs
and line drawings. Later research estab-
lished that infants as young as 5 months
old can recognize people and objects in
photographs and drawings of them (e.g.,
DeLoache, Strauss, & Maynard, 1979;
Dirks & Gibson, 1977), and even newborns
can recognize two-dimensional versions of
three-dimensional objects (Slater, Morison,
& Rose, 1984).
Despite their precocious perception of
pictures, infants do not understand their
nature. The four babies shown here—two
from the United States and two from a rural
village in West Africa—are all manually ex-
ploring depicted objects. Although these
9-month-old babies can perceive the differ-
ence between pictures and objects, they do
not yet understand what two-dimensionality
means; hence, they attempt to treat pic-
tured objects as if they were real objects—
with an inevitable lack of success. By 19
months of age and after substantial expe-
rience with pictures, American infants no
longer manually investigate pictures, ap-
parently having learned that pictures are
to look at and talk about, but not to feel,
pick up, or eat (DeLoache et al., 1998;
Pierroutsakos & DeLoache, 2003). In short,
they have come to understand the sym-
bolic nature of pictures and appreciate that
a depicted object stands for a real object
(Preissler & Carey, 2003).
Whereas most Western infants live in en-
vironments filled with pictured objects, in-
fants in other cultures often lack experience
with such images. Fascinating cross-cultural
research suggests that, in fact, infants who
grow up in homes and communities with-
out pictured objects do not show the same
trajectory of understanding that pictures
are representations of real objects. In one
study, Canadian toddlers and preschool-
ers outstripped their peers from rural India
and Peru in their ability to match line draw-
ings of objects to toy objects (Callaghan et
al., 2011). Similarly, toddlers from rural
Tanzania, who had no prior exposure to pic-
tures, had greater difficulty than did North
American toddlers in generalizing the names
of objects in color photographs to the ob-
jects themselves (Walker, Walker, & Ganea,
2013). These studies suggest that under-
standing the relationship between 2D im-
ages and 3D objects requires experience
with pictorial media.
BOX 5.2: a closer look
PICTURE PERCEPTION
A
LL
:
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,
1
9
9
8
these 9-month-old infants—two from the
United States and two from West africa—are
responding to pictures of objects as if they
were real objects. they do not yet know the
true nature of pictures. (From DeLoache et
al., 1998)

184 n chapter 5 SEEING, THINKING, AND DOING IN INFANCY
Infants are adept at perceiving patterns in the streams of sound they hear. They
are remarkably proficient, for example, at detecting subtle differences in the sounds
of human speech, an ability we will review in detail in our discussion of language
development in Chapter 6. Here we will focus on another realm in which infants
display an impressive degree of auditory sensitivity—music.
Music Perception
Infants are sensitive to music, as shown by the fact that caregivers around the world
sing while caring for their infants (Trehub & Schellenberg, 1995). In the United
States, for example, 60% of parents sing or play music to their children every day
(Custodero, Britto, & Brooks-Gunn, 2003).
When adults sing to their infants, they do so in a characteristic fashion which,
like the infant-directed speech register we will discuss in Chapter 6 (pages 223–
224), tends to be slower and higher-pitched, and to suggest more positive af-
fect, than does singing directed toward adult listeners. Perhaps because of these
characteristics, infants prefer infant-directed singing over adult-directed singing
(Masataka, 1999; Trainor, 1996). Indeed, infant-directed singing even appears to
trump infant-directed speech as a preferred stimulus, as suggested by a study in
which 6-month-olds were more attentive to videos of their own mother singing
than to videos of her speaking (Nakata & Trehub, 2004).
Beyond their interest in music, infants are also able to remember what they
hear, recognizing musical excerpts several weeks after first being exposed to them
(Saffran, Loman, & Robertson, 2000; Trainor, Wu, & Tsang, 2004; Volkova,
Trehub, & Schellenberg, 2006). These memories are surprisingly detailed, and in-
clude aspects of the pitch, timbre, and tempo of the original performances. For ex-
ample, when 7-month-olds were tested on songs that they had heard in a particular
key two weeks earlier, they listened longer when the same songs were sung in a new
key than when they were sung in the original key (Volkova et al., 2006). This indi-
cates that infants not only discriminated between performances of the same song in
two different keys but also continued to remember the original key of the song two
weeks after they had last heard it sung.
In many ways, infant music perception is adultlike. One well-studied example is
the preference for consonant intervals (e.g., octaves, or perfect fifths like the open-
ing notes of the ABCs song) over dissonant intervals (e.g., augmented fourths like
the opening of “Maria” from the musical West Side Story, or minor seconds like the
theme from the film Jaws). From Pythagoras to Galileo to the present day, many
scientists and scholars have argued that consonant tones are inherently pleasing
to human ears, whereas dissonant tones are unpleasant (Schellenberg & Trehub,
1996; Trehub & Schellenberg, 1995). To see if infants agree, researchers employ a
simple but reliable procedure. They draw infants’ attention toward an audio speaker
by using a visually interesting stimulus (e.g., a flashing light) and then play music
through the speaker. The length of time infants look at the speaker (actually, at the
visual stimulus located in the same position as the speaker) is taken as a measure of
their interest in, or preference for, the music emanating from the speaker.
Studies have shown that infants pay more attention to a consonant version of a
piece of music, whether a folk song or a minuet, than to a dissonant one (Trainor
& Heinmiller, 1998; Zentner & Kagan, 1996, 1998). A study by Masataka revealed
that even 2-day-old infants show this pattern of preference (Masataka, 2006). This
study is particularly notable in that it was conducted with hearing infants whose
mothers were deaf, making it unlikely that the infants would have had prenatal

P E R C E P T I O N n 185
exposure to singing. These results suggest that preferences for consonant music as
opposed to dissonant music are not due to musical experience. Indeed, other spe-
cies (including chicks, macaque monkeys, and chimps) also show preferences for
consonant music, supporting the view that preferences for consonance over disso-
nance are unrelated to musical experience (e.g., Chiandetti & Vallortigara, 2011;
Sugimoto et al., 2010).
In certain other aspects of music perception, infants diverge markedly from
adult listeners. One of the most interesting differences is in the area of melodic
perception, in which infants can make perceptual discriminations that adults can-
not. In one set of studies, 8-month-old infants and adults listened to a brief repeat-
ing melody that was consistent with the harmonic conventions of Western music.
Then, in a series of test trials, they heard the melody again—but with one note
changed. On some trials, the changed note was in the same key as the melody; on
others, it fell outside the key. Both infants and adults noticed changes that violated
the key of the melody, but only the infants noticed the changes that stayed within
the key of the melody (Trainor & Trehub, 1992). Does this mean that infants are
more musically attuned than adults? Probably not. What appeared to be a height-
ened musical sensitivity in the infant participants was more likely a reflection of
their relative lack of implicit knowledge about Western music. Because it takes
years to acquire culture-specific familiarity with musical key structures, the within-
key and out-of-key changes were equally salient to the infant listeners (Trainor &
Trehub, 1994). For adults, years of hearing music makes it very difficult to detect
note changes that stay within a key.
In a similar way, infants are also more “sensitive” to aspects of musical rhythm than
adults are. Musical systems vary in the complexity of their rhythmic patterning; the
rhythms of Western music, for example, are relatively simple compared with those
of some cultures in Africa, India, and Europe. Hannon and Trehub (2005a, 2005b)
tested adults and 6-month-olds on their ability to detect meter-disrupting changes
in simple rhythms versus complex rhythms. Notably, some of the adults lived in the
Balkans, where the local music contains complex rhythmic patterns, and others lived
in North America, where popular music is characterized by simpler rhythmic pat-
terns. The results revealed that all groups detected changes in the simple rhythms,
but only the North American infants and the Balkan adults detected changes in
the complex rhythms. Thus, North American 6-month-olds outperformed North
American adults on this task. A follow-up study asked whether North American
12-month-olds and adults could be trained to detect such changes in the complex
rhythms. After 2 weeks of exposure to the Balkan rhythms, the 12-month-olds were
able to detect changes in complex rhythms, but the adults still failed to do so.
These examples from the musical domain suggest that, with experience, there
is a process of perceptual narrowing. Infants, who are relatively inexperienced with
music, can detect differences between musical stimuli that adults cannot. Develop-
mental changes in which experience fine-tunes the perceptual system are observed
across numerous domains. Indeed, you saw this process of perceptual narrowing in
our discussion of face perception in Box 5.1, and you will see the same pattern of
development when we examine intermodal aspects of speech perception (page 187)
and, quite prominently, when we take up language acquisition in Chapter 6. Across
all these examples and in other domains, experience leads the young learner to
begin to “lose” the ability to make distinctions that he or she could make at earlier
points in development. In each case, this perceptual narrowing permits the devel-
oping child to become especially attuned to patterns in biological and social stimuli
that are important in their environment.

186 n chapter 5 SEEING, THINKING, AND DOING IN INFANCY
Taste and Smell
As you learned in Chapter 2 (page 53), sensitivity to taste and smell develops be-
fore birth, and newborns prefer sweet flavors. Preferences for smells are also present
very early in life. Newborns prefer the smell of the natural food source for human
infants—breast milk (Marlier & Schaal, 2005). Smell plays a powerful role in how
a variety of infant mammals learn to recognize their mothers. It probably does the
same for humans, as shown by studies in which infants chose between the scent of
their own mother and that of another woman. A pad that an infant’s mother had
worn next to her breast was placed on one side of the infant’s head and a pad worn
by a different woman was placed on the other side. Two-week-old infants turned
more often and spent more time oriented to the pad infused with their mother’s
unique scent (MacFarlane, 1975; Porter et al., 1992).
Touch
Another important way that infants learn about the environ-
ment is through active touch, initially through their mouth and
tongue, and later with their hands and fingers. Oral exploration
dominates for the first few months, as infants mouth and suck
on their own fingers and toes, as well as virtually any object they
come into contact with. (This is why it is so important to keep
small, swallowable objects away from babies.) Through their ar-
dent oral exploration, babies presumably learn about their own
bodies (or at least the parts they can get their mouths on), as well
as about the texture, taste, and other properties of the objects
they encounter.
From around the age of 4 months, as infants gain greater con-
trol over their hand and arm movements, manual exploration
increases and gradually takes precedence over oral exploration.
Infants actively rub, finger, probe, and bang objects, and their ac-
tions become increasingly specific to the properties of the objects.
For example, they tend to rub textured objects and bang rigid
ones. Increasing manual control facilitates visual exploration in
that infants can hold interesting objects in order to examine them
more closely, rotating the objects to view them from different
angles and transferring them from hand to hand to get a better
view (Bushnell & Boudreau, 1991; Lockman & McHale, 1989;
Rochat, 1989; Ruff, 1986).
Intermodal Perception
Most events that both adults and infants experience involve simultaneous stimula-
tion through multiple sensory modalities. In the crystal-goblet-falling-on-tile-floor
event witnessed by Benjamin, the shattering glass provided both visual and audi-
tory stimulation. Through the phenomenon of intermodal perception, the com-
bining of information from two or more sensory systems, Ben’s parents perceived
the auditory and visual stimulation as a unitary, coherent event. It is likely that
4-month-old Ben did, too.
According to Piaget (1954), information from different sensory modalities is ini-
tially separate, and only after some months do infants become capable of forming
Initially, every object that a baby can pick
up gets directed to his or her mouth for oral
exploration—whether or not it will fit. Later,
infants are more inclined to explore objects
visually, thereby showing an interest in the
object itself.
G
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intermodal perception n the com-
bining of information from two or more
sensory systems
S
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P E R C E P T I O N n 187
associations between how things look and how they sound, taste, feel, and so on.
However, it has become abundantly clear that from very early on, infants inte-
grate information from different senses. Research has shown, for example, that very
young infants link their oral and visual experiences. In studies with newborns (Kaye
& Bower, 1994) and 1-month-olds (Meltzoff & Borton, 1979), infants sucked on
a pacifier that they were prevented from seeing. They were then shown a picture of
the pacifier that had been in their mouth and a picture of a novel pacifier of a dif-
ferent shape or texture. The infants looked longer at the pacifier they had sucked
on. Thus, these infants could visually recognize an object they had experienced only
through oral exploration.
When infants become capable of exploring objects manually, they readily inte-
grate their visual and tactile experience. In one study, for example, 4-month-olds
were allowed to hold and feel, but not see, a pair of rings that were connected by
either a rigid bar or a string. When the babies were shown both types of rings,
they recognized the ones they had previously explored with their hands (Streri &
Spelke, 1988).
Researchers have also discovered that infants possess a variety of forms of
auditory–visual intermodal perception. In studies of this mode of perception, in-
fants simultaneously view two different videos, side by side, while listening to a
soundtrack that is synchronized with one of the videos but not the other. If an infant
responds more to the video that goes with the soundtrack, it is taken as evidence
that the infant detects the common structure in the auditory and visual information.
In a classic study using this procedure, Spelke (1976) showed 4-month-olds two
videos, one of a person playing peekaboo and the other of a hand beating a drum-
stick against a block. The infants responded more to the film that matched the
sounds they were hearing. When they heard a voice saying “Peekaboo,” they looked
more at the person, but when they heard a beating sound, they looked longer at the
hand. In subsequent studies, infants showed finer discriminations. For example,
4-month-olds responded more to a film of a “hopping” toy animal in which the
sounds of impact coincided with the animal’s landing on a surface than they did to
a film in which the impact sounds occurred while the animal was in midair (Spelke,
1979). At this age, infants can also draw more abstract connections between sights
and sounds. For example, 3- to 4-month-olds look longer at visual displays in
which dimensions in each modality are congruent, such as a ball rising and falling
at the same rate as a whistle rising and falling in pitch (Walker et al., 2010).
Similar studies have found that infants are especially sensitive to the relation
between human faces and voices. Between 5 and 7 months of age, infants notice
the connection between emotional expressions in faces and voices (Soken & Pick,
1992; Walker-Andrews, 1997). When infants hear a happy voice, they look longer
at a smiling face, and they look longer at an angry face when they hear an angry
voice. Infants are also attuned to the match between faces producing speech and
the sounds of speech. When 4-month-olds are shown side-by-side films of a per-
son talking while they are listening to a soundtrack that matches one of the films,
they look longer at the face whose lip movements are synchronized with the speech
they hear (Spelke & Cortelyou, 1980; Walker-Andrews, 1997). Four-month-olds
even detect the relation between specific speech sounds, such as “a” and “i,” and the
specific lip movements associated with them (Kuhl & Meltzoff, 1982, 1984).
However, the processes of perceptual narrowing that we have noted elsewhere
also occur in intermodal perception. Young infants can detect correspondences
between speech sounds and facial movements for nonnative speech sounds (those
not present in their native language), but older infants cannot (Pons et al., 2009).
a setup like this one enables researchers to
study auditory–visual intermodal perception.
the two monitors display different films, one
of which is coordinated with a soundtrack.
the video camera records the infant’s
looking toward the two screens.
Camera
Monitor
Child on mother’s lap
Hidden speaker

188 n chapter 5 SEEING, THINKING, AND DOING IN INFANCY
Similarly, young infants can detect the correspondence between monkey fa-
cial movements and monkey vocalizations, but older infants are unable to do so
(Lewkowicz & Ghazanfar, 2006). Experience thus fine-tunes the types of inter-
modal correspondences that infants detect.
Infants can do more than detect relationships between information across mo-
dalities: they can use information in one modality to interpret ambiguous infor-
mation in another modality. In an ingenious series of experiments, 7-month-olds
listened to a musical rhythm that was ambiguous and could be interpreted in either
duple or triple time (Phillips-Silver & Trainor, 2005). While infants were listening,
they were bounced up and down at a rate matching either a duple- or triple-time
interpretation of the ambiguous rhythm. When tested, infants preferred to listen to
the version of the rhythm that fit the pattern in which they were bouncing. These
results indicate that infants readily integrate vestibular information with auditory
information: how infants were bounced altered how infants interpreted what they
were hearing.
review:
Using a variety of special techniques, developmental psychologists have discovered an enor-
mous amount about perceptual development in infancy. They have documented rapid de-
velopment of basic visual abilities from birth over the next few months, discovering that by
approximately 8 months of age infants’ visual acuity, scanning patterns, and color perception
are similar to those of adults. Some forms of depth perception are present at birth, whereas
others develop in the ensuing months. By 5 to 7 months of age, infants actively integrate
separate elements of visual displays to perceive coherent patterns. They use many sources of
information, including movement and their knowledge of their surroundings, for object seg-
regation. Faces are of particular interest to infant perceivers.
Research on auditory perception has shown that right from birth, babies turn toward
sounds they hear. They are quite sensitive to music and display some of the same musical
preferences adults do, such as a preference for consonance over dissonance. Infants also
show perceptual abilities for music that exceed those of adults, whose auditory processing
has been shaped by years of musical listening. Smell and touch both play an important role in
infants’ interaction with the world around them. The crucial ability to link what they perceive
in separate modalities to experience unitary, coherent events is present in a simple form at
birth, but more complex associations develop gradually.
There is much in recent research to encourage anyone of a nativist persuasion: neonates
show remarkable perceptual abilities that cannot be due to experience, even prenatal expe-
rience. At the same time, most perceptual skills also show development over time, much of
which clearly involves learning. Infants gradually become more adultlike in their perceptual
abilities through perceptual narrowing: as expertise increases (via learning) within and across
modalities, infants lose the ability to distinguish between less familiar sights and sounds,
becoming increasingly attuned to their native environment.
Motor Development
As you learned in Chapter 2, human movement starts well before birth, as the
fetus floats weightlessly in amniotic fluid. After birth, the newborn’s movements
are jerky and relatively uncoordinated, in part because of physical and neurological
immaturity and in part because the baby is experiencing the full effects of gravity
for the first time. As you will see in this section, the story of how the uncoordinated
newborn, a prisoner of gravity, becomes a competent toddler confidently exploring
the environment is remarkably complicated.

M O T O R D E V E L O P M E N T n 189
Reflexes
Newborns start off with some tightly organized patterns of action known as neona-
tal reflexes. Some reflexes, such as withdrawal from a painful stimulus, have clear
adaptive value; others have no known adaptive significance. In the grasping reflex,
newborns close their fingers around anything that presses against the palm of their
hand. When stroked on the cheek near their mouth, infants exhibit the rooting
reflex, turning their head in the direction of the touch and opening their mouth.
Thus, when their cheek comes into contact with their mother’s breast, they turn
toward the breast, opening their mouth as they do. Oral contact with the nipple
then sets off a sucking reflex, followed by the swallowing reflex, both of which in-
crease the baby’s chance of getting nourishment and ultimately of surviving. These
reflexes are not fully automatic; for example, a rooting reflex is more likely to occur
when an infant is hungry.
No benefit is known to be associated with other reflexes, such as the tonic neck
reflex: when an infant’s head turns or is turned to one side, the arm on that side of
the body extends, while the arm and knee on the other side flex. It is thought that
the tonic neck reflex involves an effort by the baby to get and keep its hand in view
(von Hofsten, 2004).
Neonatal reflexes: (a) Grasping
(c) Sucking
(b) rooting
(d) tonic neck reflex
C
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reflexes n innate, fixed patterns of
action that occur in response to particular
stimulation

190 n chapter 5 SEEING, THINKING, AND DOING IN INFANCY
The presence of strong reflexes at birth is a sign that the newborn’s central ner-
vous system is in good shape. Reflexes that are either unusually weak or unusu-
ally vigorous may signal brain damage. Most of the neonatal reflexes disappear on
a regular schedule, although some—including coughing, sneezing, blinking, and
withdrawing from pain—remain throughout life. Persistence of a neonatal reflex
beyond the point at which it is expected to disappear can indicate a neurological
problem.
Motor Milestones
Infants progress quickly in acquiring the basic movement patterns of our species,
shown in Figure 5.9. As you will see, the achievement of each of the major “motor
milestones” of infancy, especially walking, constitutes a major advance, and provides
new ways for infants to interact with the world.
The average ages that Figure 5.9 gives for the development of each of these
important motor skills are based on research with Western, primarily North
American, infants. There are, of course, tremendous individual differences in the
ages at which these milestones are achieved. Of particular interest is the fact that
the degree to which motor skills are encouraged varies from one culture to another,
and such variation can affect the course of motor development. Indeed, some cul-
tures actively discourage early locomotion. In modern urban China, for example,
infants are typically placed on beds and surrounded by thick pillows to keep them
from crawling on the dirty floor (Campos et al., 2000). These restrictions make it
difficult for infants to develop the muscle strength required to support their upper
trunk, which is necessary for crawling. Among the Aché, a nomadic people who
Age (in months)
D
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Prone, lifts head
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
Prone, chest up, uses arms for support
Rolls over
Supports some weight with legs
Sits without support
Stands with support
Pulls self to stand
Walks using furniture for support
Stands alone easily
Walks alone easily
FIGURE 5.9 the major milestones
of motor development in infancy the
average age and range of ages for achieve-
ment of each milestone are shown. Note
that these age norms are based on research
with healthy, well-nourished North american
infants.

M O T O R D E V E L O P M E N T n 191
live in the rain forest of Paraguay, infants spend almost all of their first 3 years of
life being carried by their mothers or kept very close to her because of safety con-
cerns. These infants thus get relatively little opportunity early on to exercise their
locomotor skills (Kaplan & Dove, 1987).
In direct contrast, the Kipsigis people in rural Kenya actively encourage the
motor development of their infants; for example, they help their babies practice sit-
ting by propping them up in shallow holes dug in the ground to support their backs
(Super, 1976). Other groups, in West Africa and the West Indies, institute an ag-
gressive program of massage, manipulation, and stimulation designed to facilitate
their infants’ motor development (A. Gottlieb, 2004; Hopkins &
Westra, 1988).
These widely varying cultural practices can affect infants’ devel-
opment. Researchers have documented somewhat slower motor de-
velopment in Aché and Chinese infants compared with the norms
shown in Figure 5.9; Kipsigis babies and the infants who undergo
exercise regimes, on the other hand, are advanced in their motor-
skill development compared with North American infants. Even as-
pects of infant life that we take for granted in our own culture have
an effect on motor development. In a recent study, researchers asked
whether diapers—a relatively recent cultural invention—have an im-
pact on walking behavior (Cole, Lingeman, & Adolph, 2012; see
Figure 5.10). The researchers found that the same infants exhib-
ited more mature walking behavior when tested naked than when
tested diapered, despite the fact that these infants—all residents of
New York City—were accustomed to wearing diapers and had rarely
walked naked. These data beautifully demonstrate that cultural prac-
tices that are undertaken in one domain (toileting) can have unfore-
seen consequences in another domain (walking behavior).
Current Views of Motor Development
Impressed by the orderly acquisition of skills reflected in Figure 5.9, two early pio-
neers in the study of motor development, Arnold Gesell and Myrtle McGraw, con-
cluded that infants’ motor development is governed by brain maturation (Gesell &
Thompson, 1938; McGraw, 1943). In contrast, current theorists, many of whom
take a dynamic-systems approach (see Chapter 4, pages 161–167), emphasize that
early motor development results from a confluence of numerous factors that include
developing neural mechanisms, increases in infants’ strength, posture control, bal-
ance, and perceptual skills, as well as changes in body proportions and motivation
(Bertenthal & Clifton, 1998; Lockman & Thelen, 1993; von Hofsten, 2004). (Box
5.3 offers a detailed account of a program of research exemplifying this approach.)
Think for a moment about how each of these factors plays a part in infants’
gradual transition from newborns unable even to lift their head to toddlers who
walk independently, holding their upper body erect while coordinating the move-
ment of their legs that have grown strong enough to support their weight. Every
milestone in this transition is fueled by what infants can perceive of the external
world and their motivation to experience more of it. The vital role of motivation is
especially clear in infants’ determined efforts to attempt to walk when they can get
around much more efficiently by crawling. Most parents—and many researchers—
have the impression that infants derive pleasure from pushing the envelope of their
motor skills.
FIGURE 5.10 these images depict the
footprint paths for a single infant partici-
pant who was tested walking naked, wearing
lightweight disposable diapers, and wearing
bulkier cloth diapers. the most mature
walking behavior was seen in the left-most
path, in the absence of diapers (cole et al.,
2012).
Naked Diposable Cloth
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192 n chapter 5 SEEING, THINKING, AND DOING IN INFANCY
The Expanding World of the Infant
Infants’ mastery of each of the milestones shown in Figure 5.9 greatly expands their
world: there is more to see when they can sit up, more to explore when they can
reach for things themselves, and even more to discover when they can move about
on their own. In this section, we consider some of the ways that motor development
affects infants’ experience of the world.
Reaching
The development of reaching sets off a minirevolution in the infant’s life: “once
infants can reach for and grasp objects, they no longer have to wait for the world
to come to them” (Bertenthal & Clifton, 1998). However, reaching takes time to
develop. That is because, as discussed in Chapter 4, this seemingly simple behav-
ior actually involves a complex interaction of multiple, independent components,
BOX 5.3: a closer look
“THE CASE OF THE DISAPPEARING REFLEX”
One of the primary proponents of the
dynamic-systems point of view we dis-
cussed in Chapter 4 was Esther Thelen.
Early research by Thelen and her col-
leagues provides an excellent example of
this approach to investigating motor de-
velopment, as well as a good example of
how to formulate hypotheses and test them
in general. In one study, they held infants
under the arms and submerged them waist-
deep in water. As you read the following
paragraphs, see how soon you can figure
out the rationale for this somewhat strange-
sounding, but, in fact, extremely informa-
tive, experiment.
This particular study was one in a series
of investigations of what Thelen (1995) re-
ferred to as “the case of the disappearing
reflex.” The reflex in question, the stepping
reflex, can be elicited by holding a newborn
under the arms so that his or her feet touch
a surface; the baby will reflexively perform
stepping motions, lifting first one leg and
then the other in a coordinated pattern as
in walking. The reflex typically disappears
at around 2 months of age. It was long as-
sumed that the stepping reflex disappears
from the infant’s motor repertoire as a result
of cortical maturation.
However, the results of a classic study
by Zelazo, Zelazo, and Kolb (1972) were
inconsistent with this view. In that research,
2-month-old infants were given extra prac-
tice exercising their stepping reflex; as a
result, the infants continued to show the
reflex long after it would otherwise have
disappeared. Other research also showed
persistence of the stepping pattern long be-
yond 2 months of age. For one thing, the
rhythmical kicking that babies engage in
when they are lying down on their back in-
volves the same pattern of alternating leg
movement as stepping does. However, un-
like stepping, kicking continues through-
out infancy (Thelen & Fisher, 1982). For
another, when 7-month-olds (who neither
walk nor typically show the stepping reflex)
are supported on a moving treadmill, they
step smartly (Thelen, 1986). If the step-
ping reflex can be prolonged or elicited long
after it is supposedly scheduled to disap-
pear, cortical maturation cannot account
for its vanishing. Why then does it normally
disappear?
A clue was provided by the observation
that chubbier babies generally begin walk-
ing (and crawling) somewhat later than do
slimmer ones. Thelen reasoned that in-
fants’ very rapid weight gain in the first few
weeks after birth may cause their legs to get
heavier faster than they get stronger. More
strength is needed to step while upright
than to kick while lying down, and more
is needed to lift a fat leg than a thin one.
Thus, Thelen hypothesized that the solution
to the mystery might have more to do with
brawn than with brains.
Thelen and her colleagues conducted
two elegant experiments to test this hy-
pothesis (Thelen, Fisher, & Ridley- Johnson,
1984). In one, the researchers put weights
on the ankles of very young infants who
still had a stepping reflex. The amount
of weight was roughly equivalent to the
amount of fat typically gained in the first
few months. When the weight was added,
the babies suddenly stopped stepping. In
the second study, older infants who no
longer showed a stepping reflex were sus-
pended waist-deep in a tank of water. As
predicted, the babies resumed stepping
when the buoyancy of the water supported
their weight. Thus, the scientific detective
work of these investigators established that
the normal disappearance of the stepping
reflex is not caused by cortical maturation,
as previously assumed. Rather, the move-
ment pattern (and its neural basis) remains
but is masked by the changing ratio of leg
weight to strength. Only by considering
multiple variables simultaneously was it
possible to solve the mystery of the disap-
pearing reflex.
stepping reflex n a neonatal reflex in
which an infant lifts first one leg and then
the other in a coordinated pattern like
walking

M O T O R D E V E L O P M E N T n 193
including muscle development, postural control, development of various perceptual
and motor skills, and so on.
Initially, infants are limited to prereaching movements—clumsy swiping to-
ward the general vicinity of objects they see (von Hofsten, 1982). At around 3 to 4
months of age, they begin successfully reaching for objects, although their move-
ments are initially somewhat jerky and poorly controlled, and their grabs fail more
often than not.
Earlier, we noted that infants’ achievements in motor development pave the way
for new experiences and opportunities to learn. A particularly compelling example
comes from studies (described in Chapter 4) in which prereaching infants were
given Velcro-patched mittens and Velcro-patched toys that allowed them to pick
up objects (Needham, Barrett, & Peterman, 2002). The manual exploration of ob-
jects made possible by these “sticky mittens” led to the infants’ increased interest in
objects and the earlier emergence of their ability to reach independently for them.
Interestingly, a related study found that the effects of the “sticky mittens” interven-
tion extended beyond objects (Libertus & Needham, 2011). Improved ability to
interact with objects gives infants additional opportunities to learn about the social
world—namely, how people interact with objects. Such improvement also provides
infants with new ways to interact with caregivers through shared play with objects.
Together, these factors serve to increase infants’ interest in social partners.
At around 7 months, as infants gain the ability to sit independently, their reach-
ing becomes quite stable, and the trajectory of their reaches is consistently smooth
and straight to the target (Spencer et al., 2000; Thelen et al., 1993; von Hofsten,
1979, 1991). The achievement of stable sitting and reaching enables infants to en-
large their sphere of action, because they can now lean forward to capture objects
previously out of reach (Bertenthal & Clifton, 1998; Rochat & Goubet, 1995).
These increased opportunities for object exploration have ramifications for visual
perception. For example, consider the difficulty of perceiving 3D objects as whole
objects. By their very nature, the front portions of 3D objects block perception of
their back portions. Nevertheless, even without X-ray vision, adults readily fill in
the nonvisible portions of 3D objects and perceive them as solid volumes. It turns
out that having more experience manipulating objects helps infants to become bet-
ter at this process of 3D object completion. Infants with better sitting and manual
skills are better at perceiving complete 3D objects from a limited view than are
infants with weaker sitting and manual skills (Soska, Adolph, & Johnson, 2010).
These sources of evidence suggest that there is a great deal of interaction between
visual development and motor development. At the same time, infants can perform
quite well on some motor tasks in the absence of vision by using auditory or vestibu-
lar cues instead. For example, vision is not necessary for accurate reaching: infants
in a completely dark room can successfully nab an invisible object that is making a
sound (Clifton et al., 1991). In addition, when reaching for objects they can see, in-
fants rarely reach for ones that are too distant, suggesting that they have some sense
of how long their arms are (Bertenthal & Clifton, 1998).
With age and practice, infants’ reaching shows increasingly clear signs of
anticipation; for example, when reaching toward a large object, infants open
their fingers widely and adjust their hand to the orientation of the desired ob-
ject (Lockman, Ashmead, & Bushnell, 1984; Newell et al., 1989). Furthermore,
like an outfielder catching a fly ball, infants can make contact with a moving
object by anticipating its trajectory and aiming their reach slightly ahead of it
(Robin, Berthier, & Clifton, 1996; von Hofsten et al., 1998). Most impressive,
10-month-olds’ approach to an object is affected by what they intend to do after
prereaching movements n clumsy
swiping movements by young infants
toward the general vicinity of objects
they see

194 n chapter 5 SEEING, THINKING, AND DOING IN INFANCY
they get their hands on it. Like adults, they reach faster for an object that they
plan to throw than for one they plan to use in a more precise fashion (Claxton,
Keen, & McCarty, 2003). However, as Figure 5.11 illustrates, infants’ anticipa-
tion skills remain quite limited for some time.
Self-Locomotion
At around 8 months of age, infants become capable for the first time in their lives
of self- locomotion, that is, of moving around in the environment on their own. No
longer limited to being only where someone else carries or puts them, their world
must seem vastly larger to them.
Infants’ first success at moving forward under their own power typically takes
the form of crawling. (Box 5.4 describes a recent increase in variability in the
Van Gogh’s painting First Steps may have
been inspired by the joy that most parents
feel at seeing their baby walk alone for the
first time and the joy the baby feels taking
those first steps. TH
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FIGURE 5.11 this right-handed
14-month-old—a participant in research
by rachel Keen and colleagues—is having
a hard time getting the applesauce he has
been offered into his mouth. as the photo
on the left shows, he has been presented
the spoon with its handle to his left, but he
has grabbed it with his dominant right hand,
which makes it extremely difficult to keep
the spoon upright on its way to his mouth. a
spill ensued.
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self-locomotion n the ability to move
oneself around in the environment

M O T O R D E V E L O P M E N T n 195
onset of crawling.) Many (perhaps most) infants begin by belly crawling or using
other idiosyncratic patterns of self-propulsion, one of which researchers refer to
as the “inchworm belly-flop” style (Adolph, Vereijken, & Denny, 1998). Most
belly crawlers then shift to hands-and-knees crawling, which is less effortful and
faster. Other styles of crawling also have colorful names: bear crawls, crab crawls,
spider crawls, commando crawls, and bum shuffles (Adolph & Robinson, 2013).
The broader point is that infants are remarkably good at finding ways to get
around prior to their being able to walk.
When infants first begin walking independently, at around 11 to 12 months,
they keep their feet relatively wide apart, which increases their base of support;
they flex slightly at the hip and knee, thereby lowering their center of gravity;
they keep their hands in the air to facilitate balance; and they have both feet on
the ground 60% of the time (as opposed to only 20% for adults) (Bertenthal &
Clifton, 1998). As they grow stronger and gain experience, their steps become
longer, straighter, and more consistent. Practice is vital to infants’ gradual mas-
tery over their initially weak muscles and precarious balance (Adolph, Vereikjen,
& Shrout, 2003). And practice they do: Adolph and colleagues (2012) found that
their sample of 12- to 19-month-olds in New York City averaged 2,368 steps
(and 17 falls) per hour!
The everyday life of the newly mobile crawler or walker is replete with chal-
lenges to locomotion—slippery floors, spongy carpets, paths cluttered with objects
and obstacles, stairs, sloping lawns, and so on. Infants must constantly evaluate
whether their developing skills are adequate to enable them to travel from one
point to another. Eleanor Gibson and her colleagues found that infants adjust
their mode of locomotion according to their perception of the properties of the
surface they want to traverse (Gibson et al., 1987; Gibson & Schmuckler, 1989).
For example, an infant who had promptly walked across a rigid plywood walkway
would prudently revert to crawling in order to get across a water bed. Box 5.5
summarizes a program of research on the early development of locomotion and
In the late 1990s, pediatricians noticed a
surprising increase in the number of visits
they received from parents worried because
their infants either began crawling quite
late or never crawled at all. Many babies
had simply gone from sitting to walking.
The cause for this genuine secular
change in motor development seems to be
traceable to the campaign, described in
Box 2.4 (page 61), to get parents to put
their babies to sleep on their backs (Davis
et al., 1998). As we discussed in Chapter
2, this public health effort has been very
successful in changing parents’ behavior
and has resulted in a remarkable reduction
in the incidence of sudden infant death
syndrome. However, it appears that regu-
larly lying on their backs makes infants less
likely to turn over on schedule. One source
of this effect may be motivational: the bet-
ter view of the environment that they have
on their backs may lessen infants’ motiva-
tion to roll over onto their stomachs, where
the view is quite restricted. But, spending
less time on their tummies, the babies have
less opportunity to discover that they can
propel themselves forward by squirming.
With less practice pushing themselves up
from lying on their stomachs, the infants’
arm strength may develop somewhat more
slowly.
In any event, the research is reassuring:
when observed at 18 months, there was no
developmental difference between infants
who had crawled on schedule and those
who had not.
BOX 5.4: applications
A RECENT SECULAR CHANGE
IN MOTOR DEVELOPMENT

196 n chapter 5 SEEING, THINKING, AND DOING IN INFANCY
other forms of motor behavior in infancy, focusing specifically on the integration
of perception and locomotion.
The challenge that young children experience in integrating perceptual in-
formation in the planning and execution of actions sometimes results in quite
surprising behaviors, especially when children fail to meet the challenge. A par-
ticularly dramatic example of failure in the integration of perception and action is
provided by scale errors (Brownell, Zerwas, & Ramani, 2007; DeLoache, Uttal,
The interdependence of different develop-
mental domains is beautifully illustrated
by a rich and fascinating series of experi-
ments conducted over five decades. This
work started with a landmark study by El-
eanor Gibson and Richard Walk (1960) that
addressed the question of whether infants
can perceive depth. It has culminated in
research linking depth perception, locomo-
tion, cognitive abilities, emotion, and the so-
cial context of development.
To answer the depth-perception question,
Gibson and Walk used an apparatus known
as the “visual cliff.” As the photo shows,
the visual cliff consists of a thick sheet of
plexiglass that can support the weight of an
infant or toddler. A platform across the mid-
dle divides the apparatus into two sides. A
checked pattern right under the glass on one
side makes it look like a solid, safe surface.
On the other side, the same pattern is far
beneath the glass, and the contrast in the
apparent size of the checks makes it look
as though there is a dangerous drop-off—a
“cliff”—between the two sides.
Gibson and Walk reported that 6- to
14-month-old infants would readily cross
the shallow side of the visual cliff. They
would not, however, cross the deep side,
even when a parent was beckoning to them
to come across it. The infants were appar-
ently unwilling to venture over what looked
like a precipice—strong evidence that they
perceived and understood the significance
of the depth cue of relative size.
Karen Adolph, who had been a student
of Gibson, has conducted extensive re-
search on the relation between perception
and action in infancy. Adolph and her col-
leagues have discovered surprising discon-
tinuities in infants’ learning what they can
and cannot accomplish with their develop-
ing locomotor and postural skills (Adolph,
1997, 2000; Adolph, Eppler, & Gibson,
1993; Adolph et al., 2003; Eppler, Adolph,
& Weiner, 1996). This research exempli-
fies our theme of mechanisms of change, in
which variation and selection produce de-
velopmental change.
As a way of studying the relation between
early motor abilities and judgment, the in-
vestigators asked parents to try to entice
their infants to lean over or crawl across
gaps of varying widths in an elevated surface
or to crawl or walk down sloping walkways
that varied in how steep they were. Some
of these tasks were possible for a given in-
fant; the baby would have no trouble, for
example, negotiating a slope of a particular
steepness. Others, however, were impossi-
ble for that infant. Would the babies identify
which tasks were which? (An experimenter
always hovered nearby to catch any infant
who misjudged his or her prowess.)
The photos on the next page show how
infants behaved on slopes when beckoned
by an adult (usually their mother). In their
first weeks of crawling, infants (averaging
around 8½ months in age) unhesitatingly
and competently went down shallow slopes.
Confronted with slopes that were too steep
to crawl down, the babies typically paused
for a moment, but then launched themselves
headfirst anyway (requiring the experimenter
to catch hold of them). With more weeks of
crawling practice, the babies got better at
judging when a slope was simply too steep
and should be avoided. They also improved
at devising strategies to get down somewhat
steep slopes, such as turning around and
cautiously inching backward down the slope.
BOX 5.5: a closer look
“GANGWAY—I’M COMING DOWN”
are close to being able to make it down a
relatively steep walkway can be rather eas-
ily discouraged from trying to do so by their
mother telling them, “No! Stop!” Con-
versely, enthusiastic encouragement from
a parent can lead an inexperienced crawler
or walker to attempt a currently too-steep
slope. Thus, the child uses both perceptual
and social information in deciding what to
do. In this case, the information is obtained
through social referencing, the child’s use of
another person’s emotional response to an
uncertain situation to decide how to behave
(see Chapter 10, page 417).
A key finding of Adolph’s research is that
infants have to learn from experience what
they can and cannot do with respect to each
new motor skill that they master. Just like
the new crawlers and walkers who literally
X-ref
this infant is refusing to cross the deep side
of the visual cliff, even though his mother
is calling and beckoning to him from the
other side. CO
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scale error n the attempt by a young
child to perform an action on a miniature
object that is impossible due to the large
discrepancy in the relative sizes of the
child and the object

M O T O R D E V E L O P M E N T n 197
However, when the infants started walking,
they again misjudged which slopes they could
get down using their new mode of locomotion
and tried to walk down slopes that were too
steep for them. In other words, they failed to
transfer what they had learned about crawl-
ing down slopes to walking down them. Thus,
infants apparently have to learn through ex-
perience how to integrate perceptual infor-
mation with each new motor behavior they
develop. With experience comes increased
flexibility, allowing access to multiple strat-
egies for solving previously intractable
problems, including laboratory-created chal-
lenges such as descending impossibly steep
slopes or crossing narrow bridges with wobbly
handrails (Adolph & Robinson, 2013).
Infants’ decisions in such situations also
depend on social information. Infants who
are close to being able to make it down a
relatively steep walkway can be rather eas-
ily discouraged from trying to do so by their
mother telling them, “No! Stop!” Con-
versely, enthusiastic encouragement from
a parent can lead an inexperienced crawler
or walker to attempt a currently too-steep
slope. Thus, the child uses both perceptual
and social information in deciding what to
do. In this case, the information is obtained
through social referencing, the child’s use of
another person’s emotional response to an
uncertain situation to decide how to behave
(see Chapter 10, page 417).
A key finding of Adolph’s research is that
infants have to learn from experience what
they can and cannot do with respect to each
new motor skill that they master. Just like
the new crawlers and walkers who literally
X-ref
plunge ahead when put atop a sloping
walkway, an infant who has just developed
the ability to sit will lean too far out over
a gap in a platform in an attempt to snag
an out-of-reach toy and would fall over the
edge if not for the ever-present reseacher–
catcher. And, like the experienced crawlers
and walkers who pause to make a prudent
judgment about whether or not to try a
descent, an infant who has been capable
of sitting unsupported for some time can
judge whether the gap is too wide to lean
across and will stay put if it appears to be
so. These highly consistent findings across
a variety of motor skills have made a very
important contribution to our understanding
of how infants learn to interact successfully
with their environment.
Integrating perceptual information with new motor skills. researcher
Karen adolph will need to rescue the newly crawling young infant
on the left, who does not realize that this slope is too steep for her
current level of crawling expertise. In contrast, the experienced walker
on the right is judiciously deciding that the slope is too steep for him
to walk down.
B
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& Rosengren, 2004; Ware et al., 2006). In this kind of error, very young children
try to do something with a miniature replica object that is far too small for the
action to be at all possible. Toddlers will attempt, in all seriousness, to sit in a tiny,
dollhouse-sized chair or to get into a small toy car (see Figure 5.12). In commit-
ting a scale error, the child momentarily fails to take into account the relation
between his or her own body and the size of the target object. These errors are
hypothesized to result from a failure to integrate visual information represented

198 n chapter 5 SEEING, THINKING, AND DOING IN INFANCY
in two different areas of the brain in the service of action. With development, the
incidence of scale errors diminishes, although even adults make a variety of action
errors (e.g., putting a cup of water into the cupboard instead of the microwave or
trying to squeeze into a too tight pair of pants).
review:
Typically developing infants display a similar sequence of milestones in the development of
motor behavior, starting with a common set of neonatal reflexes. Although the timing of these
milestones may differ across infants, and is affected by cultural differences, their order rarely
varies. Researchers emphasize the pervasive interconnectedness between infants’ motor be-
havior, perception, and motivation, as well as the many ways that infants’ experience of the
world changes as motor skills improve. In the development of self-locomotion (crawling, walk-
ing), infants adopt a variety of different movement patterns and strategies to get around and
to cope with different environmental challenges. With experience, infants begin to develop
the crucial ability to make accurate judgments about what actions they are and are not ca-
pable of performing.
Learning
Who do you think learned more today—you or a 10-month-old infant? We’d bet
on the baby, just because there is so much that is new to an infant. Think back to
baby Benjamin in the kitchen with his parents. A wealth of learning opportunities
was embedded in that everyday scene. Benjamin was, for example, gaining experi-
ence with some of the differences between animate and inanimate entities, with the
particular sights and sounds that occur together in events, with the consequences of
objects’ losing support (including the effect of this event on his parents’ emotional
state), and so on. He also experienced consequences of his own behavior, such as
his parents’ response to his crying.
In this section, we review seven different types of learning by which infants
profit from their experience and acquire knowledge of the world. Some of the
questions that developmental psychologists have addressed with respect to infants’
learning include at what age the different forms of learning appear and in what
ways learning in infancy is related to later cognitive abilities. Another important
question concerns the extent to which infants find some things easier or more dif-
ficult to learn. The learning abilities described below are implicated in developmen-
tal achievements across every domain of human functioning, from visual perception
to social skills. It is thus impossible to think about development without consid-
ering the nature of the learning mechanisms that support developmental change.
FIGURE 5.12 Scale errors these three
children are making scale errors, treating a
miniature object as if it were a much larger
one. the girl on the left has just fallen off
the toy slide she was trying to go down; the
boy in the middle is persistently trying to
get into a very small car; and the boy on
the right is attempting to sit in a miniature
chair. (From DeLoache et al., 2004)
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Habituation
The simplest form of learning is recognizing
something that has been experienced before. As
we discussed in Chapter 2 and again earlier in
this chapter, babies—like everybody else—tend
to respond relatively less to stimuli they have
previously experienced, and relatively more to
novel stimuli (see Figure 5.13). The occurrence
of habituation in response to repeated stimula-
tion reveals that learning has taken place; the
infant has formed a memory representation of
the repeated, and now familiar, stimulus. Habit-
uation is highly adaptive: diminished attention
to what is familiar enables infants to pay atten-
tion to, and learn about, what is new.
The speed with which an infant habituates
is believed to reflect the general efficiency of
the infant’s processing of information. Related
measures of attention, including duration of
looking and degree of novelty preference, also
indicate speed and efficiency of processing. A
substantial and surprising degree of continu-
ity has been found between these measures in
infancy and general cognitive ability later in
life. Infants who habituate relatively rapidly,
who take relatively short looks at visual stim-
uli, and/or who show a greater preference for
novelty tend to have higher IQs when tested
as much as 18 years later (Colombo et al.,
2004; Rose & Feldman, 1997). Thus, habitua-
tion, one of the earliest and simplest forms of
human learning, is fundamental to basic cog-
nitive development.
Perceptual Learning
From their first moments of life, infants actively search for order and regularity
in the world around them, and they learn a great deal from simply paying close
attention to the objects and events they perceive. According to Eleanor Gibson
(1988), the key process in perceptual learning is differentiation—extracting from
the events in the environment the relation between those elements that are con-
stant. For example, infants learn the association between tone of voice and facial
expression because, in their experience, a pleasant, happy, or eagerly excited tone of
voice occurs with a smiling face—not a frowning one—and a harsh, angry tone of
voice occurs with a frowning face—not a smiling one.
A particularly important part of perceptual learning is the infant’s discovery of
affordances—that is, the possibilities for action offered, or afforded, by objects and
situations (Gibson, 1988). They discover, for example, that small objects—but not
large ones—afford the possibility of being picked up, that liquid affords the possibil-
ity of being poured and spilled, that chairs of a certain size afford the possibility of
FIGURE 5.13 habituation this 3-month-old pro-
vides a vivid demonstration of habituation. She is
seated in front of a screen on which photographs
are displayed. at the first appearance of a photo of
a face, her eyes widen and she stares intently at it.
With three more presentations of the same picture,
her interest wanes and a yawn appears. By its fifth
appearance, other things are attracting the baby’s
attention, and by the sixth even her dress is more
interesting. When a new face finally appears, her
interest in something novel is evident. (From Maurer
& Maurer, 1988)
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differentiation n the extraction from the
constantly changing stimulation in the
environment of those elements that are
invariant, or stable
affordances n the possibilities for
action offered by objects and situations

200 n chapter 5 SEEING, THINKING, AND DOING IN INFANCY
being sat on, and so forth. Infants discover affordances
by figuring out the relations between their own bodies
and abilities and the things around them. As we dis-
cussed earlier, for example, infants learn that solid, flat
surfaces afford stable walking, whereas squishy, slick, or
steeply sloping ones do not (e.g., Adolph, 2008).
Perceptual learning underlies the development of
some, but not all, aspects of intermodal perception. As
we noted previously, learning is not required to detect
an event involving sight and sound as unitary; thus,
baby Benjamin naturally perceives a single, coherent
event the first time he sees and hears a crystal goblet
crashing on the floor. However, one does have to learn
what particular sights and sounds go together, so only
through experience does Ben know that a particular
tinkling sound means a glass is being broken. As you
have seen, young infants are sensitive early on to the synchrony of lip movements
and vocal sounds, but they have to learn to relate the unique sight of their mother’s
face with the unique sound of her voice, which they accomplish by 3½ months of
age (Spelke & Owsley, 1979). The necessity for perceptual learning is especially
clear with regard to events that involve arbitrary relations, such as an association
between the color of a cup and the taste of the food inside. The fact that 7-month-
olds can be taught color–taste associations in the lab (Reardon & Bushnell, 1988)
would come as no surprise to those parents whose infants clamp their mouths shut
at the sight of a spoon conveying anything green.
Statistical Learning
A related type of learning also involves simply picking up information from the en-
vironment, specifically, detecting statistically predictable patterns (Aslin, Saffran, &
Newport, 1998; Kirkham, Slemmer, & Johnson, 2002; Saffran, Aslin, & Newport,
1996). Our natural environment contains a high degree of regularity and redun-
dancy; certain events occur in a predictable order, certain objects appear at the same
time and place, and so on. A common example for a baby is the regularity with
which the sound of Mom’s voice is followed by the appearance of her face.
From quite early on, infants are highly sensitive to the regularity with which
one event follows another. In one study, 2- to 8-month-olds were habituated to six
simple visual shapes that were presented one after another with specified levels of
probability (Kirkham et al., 2002). For example, three pairs of colored shapes al-
ways occurred together in the same order (e.g., a square was always followed by a
cross), but the next stimulus could be any of three different shapes (e.g., a cross was
followed by a circle, triangle, or square equally often). Thus, the probability that
the cross would follow the square was 100%, but the probability that the circle (or
triangle or square) would follow the cross was 33%. In a test, the order of appear-
ance of one or more of the shapes was changed. The infants looked longer when
the structure inherent in the initial set was violated (e.g., square followed by circle).
Statistical learning abilities have been measured across numerous domains, in-
cluding music, action, and speech (Roseberry et al., 2011; Saffran & Griepentrog,
2001; Saffran et al., 1996). Even newborn infants track statistical regularities in
these domains, suggesting that statistical learning mechanisms are available at birth
if not before (Bulf, Johnson, & Valenza, 2011; Kudo et al., 2011; Teinonen et al.,
the objects surrounding this baby offer a
variety of affordances. Some can be picked
up, but others are too big for the infant’s
small hands or too heavy for her limited
strength. the rattle makes noise when
shaken, the piano, when banged. Small
objects can be inserted into the yellow con-
tainer, but larger ones won’t fit. the stuffed
toy can be enjoyably cuddled, but not the
telephone. through interacting with the
world around them, infants discover these
and many other types of affordances.
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2009). Finally, statistical learning has been proposed to be of vital importance in
language learning, as we will discuss in Chapter 6.
Several recent studies suggest that infants prefer to attend to certain types of sta-
tistical patterns over others. In particular, they appear to prefer patterns that have
some variability over patterns that are very simple (perfectly predictable) or very
complex (random) (Gerken, Balcomb, & Minton, 2011; Kidd et al., 2012). This
“Goldilocks effect”—avoiding patterns that are either too easy or too hard, while
continuing to focus on those that are just right, given the infant’s learning abilities—
suggests that infants allocate attention differently to different learning problems,
preferentially attending to those patterns that are the most informative.
Classical Conditioning
Another type of learning, classical conditioning, was first discovered by Ivan
Pavlov in his famous research with dogs (who learned an association between the
sound of a bell and the arrival of food and gradually came to salivate at the sound
of the bell alone). Classical conditioning plays a role in infants’ everyday learning
about the relations between environmental events that have relevance for them.
Consider young babies’ mealtimes, which occur frequently and have a predictable
structure. A breast or bottle contacts the infant’s mouth, eliciting the sucking reflex.
The sucking causes milk to flow into the infant’s mouth, and the infant experiences
the pleasurable sensations of a delicious taste and the satisfaction of hunger. Learn-
ing is revealed when an infant’s sucking motions begin to occur at the mere sight
of the bottle or breast.
In terms of classical conditioning, the nipple in the infant’s mouth is an
unconditioned stimulus (UCS) that reliably elicits a reflexive, unlearned
response—in this case, the sucking reflex—the unconditioned response (UCR).
Learning, or conditioning, occurs when an initially neutral stimulus—the breast
or bottle, which is the conditioned stimulus (CS)—repeatedly occurs just before
the unconditioned stimulus (the baby sees the breast or bottle before receiving the
nipple). Gradually, the originally reflexive response becomes a learned behavior, or
conditioned response (CR), triggered by exposure to the CS (anticipatory sucking
movements now begin as soon as the baby sees the breast or bottle). In other words,
the sight of the bottle or breast has become a signal of what will follow. Gradually,
the infant may also come to associate caregivers with the entire sequence, including
the pleasurable feelings that result from feeding. If so, these feelings could eventu-
ally be evoked simply by the presence of a caregiver. It is thought that many emo-
tional responses are initially learned through classical conditioning.
Instrumental Conditioning
A key form of learning for infants (and everyone else) is learning the consequences
of one’s own behavior. In everyday life, infants learn that shaking a rattle produces
an interesting sound, that cooing at Dad gets him to coo back, and that explor-
ing the dirt in a potted plant leads to a parental reprimand. This kind of learn-
ing, referred to as instrumental conditioning (or operant conditioning), involves
learning the relationship between one’s own behavior and the reward or punish-
ment it results in. Most research on instrumental conditioning in infants involves
positive reinforcement, that is, a reward that reliably follows a behavior and in-
creases the likelihood that the behavior will be repeated. Such research features
a contingency relation between the infant’s behavior and the reward: if the infant
classical conditioning n a form of
learning that consists of associating an
initially neutral stimulus with a stimulus
that always evokes a particular reflexive
response
unconditioned stimulus (UCS) n in
classical conditioning, a stimulus that
evokes a reflexive response
unconditioned response (UCR) n
in classical conditioning, a reflexive
response that is elicited by the uncondi-
tioned stimulus
conditioned stimulus (CS) n in clas-
sical conditioning, the neutral stimulus
that is repeatedly paired with the uncon-
ditioned stimulus
conditioned response (CR) n in clas-
sical conditioning, the originally reflexive
response that comes to be elicited by the
conditioned stimulus
instrumental (or operant) condi-
tioning n learning the relation between
one’s own behavior and the consequences
that result from it
positive reinforcement n a reward that
reliably follows a behavior and increases
the likelihood that the behavior will be
repeated

202 n chapter 5 SEEING, THINKING, AND DOING IN INFANCY
makes the target response, then he or she receives the reinforcement.
Table 5.1 shows a few examples of the great variety of ingenious situa-
tions that researchers have engineered in order to examine instrumental
learning in infants.
Carolyn Rovee-Collier (1997) developed an instrumental-
conditioning procedure for studying learning and memory in young
infants. In this method, experimenters tie a ribbon around a baby’s
ankle and connect it to a mobile hanging above the infant’s crib (Fig-
ure 5.14). In the course of naturally kicking their legs, infants as
young as 2 months of age quickly learn the relation between their leg
movements and the enjoyable sight of the jiggling mobile. They then
quite deliberately and often joyfully increase their rate of foot kick-
ing. The interesting mobile movement thus serves as reinforcement
for the kicking. An additional feature of this procedure is that the
intensity of the reward—the amount of movement of the mobile—
depends on the intensity of the baby’s behavior. This task has been
used extensively to investigate age-related changes in how long, and
under what circumstances, infants continue to remember that kick-
ing will activate the mobile (e.g., Rovee-Collier, 1999). Among the
findings: (1) 3-month-olds remember the kicking response for about
1 week, whereas 6-month-olds remember it for 2 weeks; (2) infants
younger than about 6 months of age remember the kicking response
only when the test mobile is identical to the training mobile, whereas
older infants remember it with novel mobiles.
Infants’ intense motivation to explore and master their environ-
ment, which we have emphasized in our active child theme, shows up
in instrumental-learning situations: infants work hard at learning to
predict and control their experience, and once control has been estab-
lished, they dislike losing it. Infants as young as 2 months old display
facial expressions of joy and interest while learning a contingency rela-
tion, and display expressions of anger when a learned response no lon-
ger produces the expected results (Lewis, Alessandri, & Sullivan, 1990;
Sullivan, Lewis, & Alessandri, 1992). In one study, for example, seven
out of eight newborns cried when they failed to receive the sweet liq-
uid they had learned would follow a head-turn response (Blass, 1990).
Infants may also learn that there are situations over which they have no con-
trol. For example, infants of depressed mothers tend to smile less and show lower
levels of positive affect than do infants whose mothers are not depressed. In part,
this may be because infants of depressed mothers learn that their smiling is rarely
rewarded by their preoccupied parent (Campbell, Cohn, & Meyers, 1995). More
generally, through contingency situations, whether in a lab or an everyday setting,
infants learn more than just the particular contingency relations to which they are
exposed. They also learn about the relation between themselves and the world and
the extent to which they can have an impact on it.
Observational Learning/Imitation
A particularly potent source of infants’ learning is their observation of other peo-
ple’s behaviors. Parents, who are often amused and sometimes embarrassed by their
toddler’s reproduction of their own behavior, are well aware that their offspring
learn a great deal through simple observation.
TABLE 5.1
Studying Instrumental conditioning in Infants
Age Group Learned Response Reinforcement
Newborns Head turn to side Drink of sucrose water
3 weeks Sucking pattern Interesting visual display
5–12 weeks Sucking pattern Keep a movie in focus
6 months Push a lever Cause a toy train to
move along a track
Source: Bruner, 1973; Hartshorn & Rovee-Collier, 1997; Siqueland & DeLucia,
1969; Siqueland & Lipsitt, 1966
FIGURE 5.14 contingency this young
infant learned within minutes that kicking
her leg would cause the mobile to move in
an interesting way; she learned the con-
tingency between her own behavior and an
external event.
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The ability to imitate the behavior of other people appears to be present very
early in life, albeit in an extremely limited form. Meltzoff and Moore (1977, 1983)
found that after newborns watch an adult model slowly and repeatedly stick out his
or her tongue, they often stick out their own tongue. By the age of 6 months, infant
imitation is quite robust. Six-month-old infants not only imitate tongue protru-
sion, but they also attempt to poke their tongue out to the side when that is what
they have seen an adult do (Meltzoff & Moore, 1994). From this age on, the scope
of infant imitation expands. Infants begin to imitate novel, and sometimes quite
strange, actions they have seen performed on objects. In one such study, infants ob-
served an experimenter performing unusual behaviors with objects, such as leaning
over from the waist to touch his or her forehead to a box, causing the box to light
up. The infants were later presented with the same objects the experimenter had
acted on. Infants as young as 6 to 9 months imitated some of the novel actions they
witnessed, even after a delay of 24 hours (Barr, Dowden, & Hayne, 1996; Bauer,
2002; Hayne, Barr, & Herbert, 2003; Meltzoff, 1988b). Fourteen-month-olds imi-
tated such actions a full week after first seeing them (Meltzoff, 1988a).
In choosing to imitate a model, infants seem to analyze the reason for the per-
son’s behavior. If infants see a model lean over and touch a box with her forehead,
they later do the same. If, however, the model remarks that she’s cold and tightly
clutches a shawl around her body as she leans over and touches a box with her
forehead, infants reach out and touch the box with their hand instead of their
head (Gergely, Bekkering, & Kiraly, 2002). They apparently reason that the model
wanted to touch the box and would have done so in a standard way if her hands
had been free. Their imitation is thus based on their analysis of the person’s inten-
tions. In general, infants are flexible in learning through imitation: as in the case of
touching the box, they can copy either the specific behavior through which a model
achieves a goal, or they can employ different behaviors to achieve the same goal the
model achieved (Buttelmann et al., 2008).
Further evidence of infants’ attention to intention comes from research in which
18-month-olds observed an adult attempting, but failing, to pull apart a small
dumbbell toy (Meltzoff, 1995a). The adult pulled on the two ends, but his hand
“slipped off,” and the dumbbell remained in one piece (Figure 5.15a). When the
infants were subsequently given the toy, they pulled the two ends apart, imitating
what the adult had intended to do, not what he had actually done. This research
also established that infants’ imitative actions are limited to human acts. A differ-
ent group of 18-month-olds watched a mechanical device with pincers grasp the
two ends of the dumbbell. The pincers either pulled apart the dumbbell or slipped
off the ends (Figure 5.15b). Regardless of what the infants had seen the mechani-
cal device do, they rarely attempted to pull apart the dumbbell themselves. Thus,
infants attempt to reproduce the behavior and intentions of other people, but not
of inanimate objects.
FIGURE 5.15 Imitating intentions
(a) When 18-month-olds see a person
ap parently try, but fail, to pull the ends off
a dumbbell, they imitate pulling the ends
off—the action the person intended to do,
not what the person actually did. (b) they
do not imitate a mechanical device at all.
(From Meltzoff, 1995a)
(a)
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204 n chapter 5 SEEING, THINKING, AND DOING IN INFANCY
Babies are by no means restricted to learning from the behavior of live adult
models. Infants as young as 15 months of age imitate actions they have seen an
adult perform on a video screen (Barr & Hayne, 1999; Meltzoff, 1988a). Peers
can also serve as models for young toddlers, as demonstrated by a study in which
well-trained 14-month-old “expert peers” performed novel actions (e.g., pushing a
button hidden inside a box to sound a buzzer) for their age-mates, either at their
preschool or in a laboratory (Hanna & Meltzoff, 1993). When the observer chil-
dren were tested in their own homes 48 hours later, they imitated what they had
seen the child model do earlier.
Current research is focused on the neural underpinnings of imitative learning.
One area that has received a good deal of attention as a potential locus for imita-
tion involves the so-called mirror neuron system, which was first identified in the
ventral premotor cortex in nonhuman primates (e.g., Gallese et al., 1996; Rizzolatti
& Craighero, 2004). In research with macaque monkeys, this system becomes ac-
tivated when the monkey engages in an action; it also is activated when the ma-
caque merely observes another monkey (or a human) engage in an action, as though
the macaque itself were engaging in the same action—hence, the name “mirror”
neuron system. (Mirror neurons were discovered when neuroscientists who were
monitoring the brain activity of a monkey noticed that when the monkey hap-
pened to see a lab assistant raising an ice cream cone to his mouth, neurons in the
monkey’s premotor cortex began firing as though the monkey were about to eat
the ice cream cone.)
The degree to which the same system is present in humans, as well as what be-
havioral domains it might affect, if any at all, is an area of hot debate. Researchers
have, however, begun to discover patterns of infant brain activity that are consis-
tent with the hypothesis that mirror neurons are present—namely, patterns of neu-
ral firing when infants are observing an action that is similar to those they display
when they are performing the same action (Marshall & Meltzoff, 2011). Future
studies using neuroscientific techniques should be informative about the roots of
imitation, identifying what infants are actually encoding as they observe the actions
of others, and how that perceptual information is transformed into self-action.
Rational Learning
As adults, we have many beliefs about the world, and we are usually surprised when
the world violates our expectations based on those beliefs. We can then adjust our
expectations based on the new information we have just received. For example, you
can infer from prior meals at your favorite Chinese restaurant that it will be serving
Chinese food the next time you go there, and your expectations would be violated if
the restaurant turned out to be serving Mexican food on your next visit. You would
then, however, update your expectations about the nature of the cuisine at this es-
tablishment. Indeed, scientific reasoning is based on precisely this sort of inference
from prior data—for example, using data drawn from a sample of a particular pop-
ulation to make predictions about that population. Infants, too, can use prior expe-
rience to generate expectations about what will happen next. This is called rational
learning because it involves integrating the learner’s prior beliefs and biases with
what actually occurs in the environment (Xu & Kushnir, 2013).
In an elegant study, Xu & Garcia (2008) demonstrated that 8-month-olds could
make predictions about simple events. Infants were shown a box containing 75
ping-pong balls; 70 were red and 5 were white. The infants then observed an ex-
perimenter close her eyes (to suggest a random selection) and draw 5 balls from the
rational learning n the ability to use
prior experiences to predict what will
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C O G N I T I O N n 205
box—either 4 red and 1 white or 4 white and 1 red—and put them on display. (The
experimenter was actually drawing preselected “random samples” from a hidden
compartment in the box.) The infants looked longer at the display with the 4 white
balls, indicating that they were surprised that the experimenter drew mostly white
balls from a box that was mostly filled with red balls. (Later in this chapter, we will
further discuss the use of so-called violation-of-expectation paradigms, which use
infants’ “surprise” at unexpected outcomes to draw inferences about their expecta-
tions.) It is important to note that the infants showed no such surprise when it was
clear that the displayed balls did not come from the box (as when the experimenter
took them from her pocket) or when they could see that the red balls were stuck to
the box and could not be removed (Denison & Xu, 2010; Teglas et al., 2007; Teglas
et al., 2011; Xu & Denison, 2009). Infants as young as 6 months of age appear to
be sensitive to the distribution of elements (here, colors) as a source of information
upon which to base future expectations (Denison, Reed, & Xu, 2013). Similar find-
ings are emerging across a number of domains, all suggesting that infants generate
inferences about the future based on prior data, in tasks ranging from word learn-
ing to social interactions, and that infants can use new experiences to adjust these
inferences (e.g., Schulz, 2012; Xu & Kushnir, 2013).
review:
Infants begin learning about the world immediately. They habituate to repeatedly encoun-
tered stimuli, form expectancies for repeated event sequences, and learn associations be-
tween particular sights and sounds that regularly occur together. Classical conditioning,
which has been demonstrated in newborn and older infants, is believed to be especially im-
portant in the learning of emotional reactions. Infants are highly sensitive to a wide range of
contingency relations between their own behavior and what follows it. A particularly powerful
form of learning for older infants is observational learning: from 6 months of age on, infants
learn many new behaviors simply by watching what other people do. Although an enormous
amount of learning goes on during the infancy period, some associations or relations are eas-
ier for babies to learn than others are. In observational learning, for example, intentionality
is a key factor. Finally, infants are able to use their accumulated experience to make rational
predictions about the future.
Cognition
Clearly, infants are capable of learning in a variety of ways. But do they actually
think? This is a question that has intrigued parents and developmental psycholo-
gists alike. Baby Benjamin’s parents have no doubt looked with wonderment at
their child, asking themselves, “What is he thinking? Is he thinking?” Developmen-
tal scientists have been working diligently to find out to what extent infants engage
in cognition (knowledge, thought, reasoning). The resulting explosion of fascinat-
ing research has established that infants’ cognitive abilities are much more impres-
sive than previously believed, although the nature and origin of these impressive
skills is a matter of considerable debate. Theorists of cognitive development vary
with respect to the relative roles they attribute to nature and nurture, especially
in terms of whether development is guided by innate knowledge structures and
special-purpose learning mechanisms or by general learning mechanisms relevant
to experiences in all domains.
So once again, the primary debate is between nativists and empiricists. Some na-
tivists argue that infants possess innate knowledge in a few domains of particular

206 n chapter 5 SEEING, THINKING, AND DOING IN INFANCY
importance (Carey & Spelke, 1994; Gelman, 2002; Gelman & Williams, 1998;
Scholl & Leslie, 1999; Spelke, 2000; Spelke & Kinzler, 2007). As you will see in
Chapter 7, for example, these nativists maintain that infants are born with some
knowledge about the physical world, such as the fact that two objects cannot oc-
cupy the same space, and that physical objects move only if something sets them in
motion. They also propose that infants possess rudimentary understandings in the
domains of biology and psychology. Other nativists emphasize specialized learning
mechanisms that enable infants to acquire this kind of knowledge rapidly and ef-
ficiently (Baillargeon, 2004; Baillargeon, Kotovsky, & Needham, 1995). According
to empiricists, infants’ mental representations of the physical world are gradually
acquired and strengthened through the general learning mechanisms that function
across multiple domains (Munakata et al., 1997). The details of this debate are exam-
ined in detail in Chapter 7 with respect to conceptual development. In the following
sections, we examine findings regarding infants’ cognitive abilities and limitations,
explanations for which both nativists and empiricists are working to pin down.
Object Knowledge
A large part of what we know about infant cognition has come from research on the
development of knowledge about objects, research originally inspired by Piaget’s
theory of sensorimotor intelligence. As you learned in Chapter 4, Piaget believed
that young infants’ understanding of the world is severely limited by an inability to
mentally represent and think about anything that they cannot currently see, hear,
touch, and so on. His tests of object permanence led him to infer that when an infant
fails to search for an object—even a favorite toy—that has disappeared from sight,
it is because the object has also disappeared from the infant’s mind.
A substantial body of research has provided strong support for Piaget’s original
observation that young infants do not manually search for hidden objects. How-
ever, as noted in Chapter 4, skepticism gradually arose about his explanation of this
fascinating phenomenon, and an overwhelming body of evidence has established
that young infants are in fact able to mentally represent and think about the exis-
tence of objects and events that are currently out of sight.
The simplest evidence for young infants’ ability to represent an object that has
vanished from sight is the fact that they will reach for objects in the dark, that is, they
reach for objects they cannot see. When young infants are shown an attractive object
and the room is then plunged into darkness, causing the object (and everything else)
to disappear from view, most babies reach to where they last saw the object, indicat-
ing that they expect it to still be there (Perris & Clifton, 1988; Stack et al., 1989).
Young infants even seem to be able to think about some characteristics of invis-
ible objects, such as their size (Clifton et al., 1991). When 6-month-olds sitting in
the dark heard the sound of a familiar large object, they reached toward it with both
hands (just as they had in the light); but they reached with only one hand when the
sound they heard was that of a familiar small object.
The majority of the evidence that young infants can represent and think about
invisible objects comes from research using the violation-of-expectancy proce-
dure. The logic of this procedure is similar to that of the visual-preference method
we discussed earlier (page 174). The basic assumption is that if infants observe an
event that violates something they know about the world, they will be surprised or
at least interested. Thus, an event that is impossible or inconsistent with respect to
the infant’s knowledge should evoke a greater response (such as longer looking or
a change in heart rate) than does a possible or consistent event.
violation-of-expectancy n a procedure
used to study infant cognition in which
infants are shown an event that should
evoke surprise or interest if it violates
something the infant knows or assumes
to be true

C O G N I T I O N n 207
The violation-of-expectancy technique was first used in a classic series of stud-
ies designed by Renée Baillargeon and her colleagues ( Baillargeon, Spelke, &
Wasserman, 1985) to see if infants too young to search for an invisible object might
nevertheless have a mental representation of its existence. In some of these studies,
infants were first habituated to the sight of a solid screen rotating back and forth
through a 180-degree arc (Figure 5.16). Then a box was placed in the screen’s path,
and the infants saw two test events. In one, the possible event, the screen rotated
upward, occluding the box as it did so, and stopped when it contacted the box. In
the impossible event, the screen continued to rotate a full 180 degrees, appearing to
pass through the space occupied by the box (which the experimenter had surrepti-
tiously removed).
Infants as young as 3½ months of age looked longer at the impossible event than
at the possible one. The researchers reasoned that the full rotation of the screen (to
which the infants had previously been habituated) would be more interesting or
surprising than the partial rotation only if the infants expected the screen to stop
when it reached the box. And the only reason for them to have had that expecta-
tion was if they thought the box was still present—that is, if they mentally repre-
sented an object they could no longer see. The results also indicate that the infants
expected the box to remain in place and did not expect the screen to be able to pass
through it.
Other studies have shown that young infants’ behavior in this situation is in-
fluenced by some of the characteristics of the occluded objects, including height
(Baillargeon, 1987a; Baillargeon, 1987b). They expect the screen to stop sooner
for a taller object than for a shorter one. Thus, research using two very different
assessments—reaching in the dark and visual attention—provides converging evi-
dence that infants who do not yet search for hidden objects nevertheless can rep-
resent their continued existence and some of their properties.
Physical Knowledge
Infants’ knowledge about the physical world is not limited to what they know and
are learning about objects. Other research has examined what they know about
physical phenomena, such as gravity. Even in the first year of life, infants seem to
appreciate that objects do not float in midair, that an object that is inadequately
supported will fall, that a nonround object placed on a stable surface will stay put,
and so forth. For example, in a series of studies in which infants observed a ball
being released on a slope, 7-month-olds (but not 5-month-olds) looked longer
when the ball moved up the slope than when it moved down, indicating that they
had expected the ball to go down (Kim & Spelke, 1992). Similarly, they looked
longer at an object that traveled more slowly as it rolled down a slope than at one
that picked up speed.
Infants also gradually come to understand under what conditions one object
can support another. Figure 5.17 summarizes infants’ reactions to simple support
problems involving boxes and a platform (Baillargeon, Needham, & DeVos, 1992;
Needham & Baillargeon, 1993). At 3 months of age, infants are surprised (they
look longer) if a box that is released in midair remains suspended (as in Figure
5.17a), rather than falling. However, as long as there is any contact at all between
the box and the platform (as in Figure 5.17b and 5.17c), these young infants do
not react when the box remains stationary. By approximately 5 months of age, they
appreciate the relevance of the type of contact involved in support. They now know
that the box will be stable only if it is released on top of the platform, so they would
FIGURE 5.16 possible versus impos-
sible events In a classic series of tests of
object permanence, renée Baillargeon first
habituated young infants to the sight of a
screen rotating through 180 degrees. then
a box was placed in the path of the screen.
In the possible event, the screen rotated
up, occluding the box, and stopped when
it reached the top of the box. In the impos-
sible event, the screen rotated up, occluding
the box, but then continued on through
180 degrees, appearing to pass through the
space where the box was. Infants looked
longer at the impossible event, showing that
they mentally represented the presence of
the invisible box. (From Baillargeon, 1987a)

208 n chapter 5 SEEING, THINKING, AND DOING IN INFANCY
be surprised by the display in Figure 5.17b. Roughly a month later,
they recognize the importance of the amount of contact, and hence
they look longer when the box in Figure 5.17c stays put with only a
small portion of its bottom surface on the platform. Shortly after their
1st birthday, infants also take into account the shape of the object and
hence are surprised if an asymmetrical object like that shown in Figure
5.17d remains stable.
Infants presumably develop this progressively refined understand-
ing of support relations between objects as a result of experience.
They observe innumerable occasions of adults placing objects on sur-
faces, and once in a while, as in the crashing crystal observed by baby
Benjamin, they see the consequences of inadequate support. And, of
course, they collect additional data through their own manipulation
of objects, including lots more evidence than their parents would like
about what happens when a milk cup is deposited on the very edge
of a high-chair tray.
Social Knowledge
In addition to acquiring knowledge about the physical world, infants
need to learn about the social world—about people and their behav-
ior. An important aspect of social knowledge that emerges relatively
early is the understanding that the behavior of others is purposive and
goal-directed. In research by Amanda Woodward (1998), 6-month-
old infants saw a hand repeatedly reach toward one of two objects sit-
ting side by side in a display (see Figure 5.18). Then the position of the
two objects was reversed, and the hand reached again. The question
was whether the infants interpreted the reaching behavior as directed
toward a particular object. They did, as shown by their looking longer
when the hand went to the new object (in the old place) than when it
reached for the old object it had reached to before. Thus, the infants
apparently interpreted the reaching behavior as directed toward a par-
ticular object. However, this was true only for a human hand; another
group of infants did not react the same way when a mechanical claw
did the reaching. (This study may remind you of the one by Meltzoff
[1995b] in which older infants imitated the actions of a human but
not of a mechanical device.) Shown the same training event (Figure
5.18a), slightly older infants (11-month-olds) were able to correctly
predict what the human hand would do next, moving their eyes to
the goal object in the test display before the hand actually moved to the goal object
(Cannon & Woodward, 2012). Again, though, they did not have the same expecta-
tions for the claw as they had for the human hand.
Other research by Sommerville, Woodward, and Needham (2005) established
that infants’ understanding of the goal-directed nature of another’s actions is re-
lated to their own experience achieving a goal. Three-month-olds, who were not
yet able to pick up objects on their own, were fitted with Velcro “sticky mittens”
(like those described earlier in this chapter and in Chapter 4) that enabled them
to capture Velcro-patched toys. Their brief experience successfully “picking up”
objects enabled them to interpret the goal-directed reaching of others in the pro-
cedure in Figure 5.18 a few months earlier than they would otherwise have been
able to do.
(a) 3 months
Initial concept:
Contact/No contact
(b) 5 months
Variable:
Type of contact
(c) 6.5 months
Variable:
Amount of contact
(d) 12.5 months
Variable:
Shape of the box
Violation detected
at each stage
FIGURE 5.17 Infants’ developing
understanding of support relations Young
infants appreciate that an object cannot
float in midair, but only gradually do they
come to understand under what conditions
one object can be supported by another.
(adapted from Baillargeon, 1998)

C O G N I T I O N n 209
Further understanding of intentionality is revealed by studies showing that older
infants even attribute intentions and goals to inanimate entities if the objects seem
to “behave” like humans. In research by Susan Johnson, 12- and 15-month-olds
were introduced to a faceless, eyeless blob that “vocalized” and moved in response
to what the infant or experimenter did, thus simulating a normal human interac-
tion ( Johnson, 2003; Johnson, Slaughter, & Carey, 1998) (see Figure 5.19). Subse-
quently, when the blob turned in one direction, the infants looked in that direction.
Thus, they seemed to be following the blob’s “gaze,” just as they would do with a
human partner, assuming that the person had turned to look at something. They
did not behave this way when the blob’s initial behavior was not contingently re-
lated to their own.
FIGURE 5.18 Infants were habituated to the
event shown in (a), a hand repeatedly reaching for
a ball on one side of a display. When tested later
with displays (b), (c), and (d), infants who saw the
hand reach for the other object looked longer than
did those who saw it reach for the ball (regardless of
the ball’s position). the pattern of results indicates
that the babies interpreted the original reaching as
object-directed. (adapted from Woodward, 1998)
(a)
(b) (c) (d)
FIGURE 5.19 When this amorphous
blobby object “responds” contingently to
infants, they tend to attribute intention to it.CO
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210 n chapter 5 SEEING, THINKING, AND DOING IN INFANCY
Older infants even interpret quite abstract displays in terms of intention and
goal-directed action (Csibra et al., 1999, 2003; Gergely et al., 2002). For ex-
ample, 12-month-olds saw a computer animation of a ball repeatedly “jumping”
over a barrier toward a ball on the other side. Adults interpret this display as the
jumping ball’s “wanting” to get to the other ball. So, apparently, did the infants.
When the barrier was removed, the infants looked longer when they saw the ball
continue to jump, just as it had done before, than when they saw it move straight
to the second ball.
Even younger infants seem to attribute intention with respect to simple dis-
plays involving small objects. In a study that used a ball, a cube, and a pyramid, all
with “googly” eyes attached, 10-month-olds watched as the ball—the “climber”—
repeatedly “attempted” to climb up a hill, each time falling back to the bottom
(Hamlin, Wynn, & Bloom, 2007; see Figure 5.20). Then the climber was alter-
nately bumped up the hill by the pyramid or pushed back down by the cube. On
the subsequent test event, the infants observed the climber alternately approach
the “helper” triangle or the “hinderer” cube. The infants looked longer when the
climber approached the “hinderer,” indicating by their surprise not only their
understanding of the “intentions” of all three objects but also their understand-
ing of what the “climber’s” response to the “helper” and “hinderer” might be ex-
pected to be.
Infants go beyond attributing intentions to others based on their actions: they
exhibit preferences for particular individuals and objects based on the individu-
als’ and objects’ actions. Earlier in this chapter, we described research focused
on infants’ visual preferences (Box 5.1). Infants also exhibit social preferences,
as evidenced by their desire to engage with some individuals over others. In
one of the first studies to demonstrate early social preferences (Kinzler, Dup-
oux, & Spelke, 2007), U.S. and French 10-month-olds saw alternating life-sized
video projections of two individuals speaking to them, one in English and one
in French. They then saw another life-sized video of the same two individuals
standing side by side behind a table, both holding an identical plush toy. Silently
and simultaneously, they smiled at the infant, then at the toy, then at the infant
again, and then leaned forward, holding the toys out as though giving them to
the infant. The moment the toys disappeared from view on the screen, they ap-
peared (through researchers’ magic) on a table in front of the infant, creating
the impression that they had come directly from the individuals in the video.
The infants’ responses suggested a social preference for the individual who had
spoken their native language: English-learning infants chose the toy offered by
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FIGURE 5.20 Viewers of the “climber”
event described above—infants and adults
alike—readily interpret it in terms of inten-
tional action. First they see the ball as
“trying” to move up a hill, but then rolling
back down, thereby “failing” to achieve its
goal of reaching the top. On some trials,
after the ball starts to roll back down, a tri-
angle appears below the ball and seems to
“push” it upward, “helping” it get to the
top. On other trials, a cube appears in front
of the ball and “hinders” it by seeming to
“push” it down the hill.

C O G N I T I O N n 211
the English speaker, whereas French-learning infants chose the toy offered by
the French speaker. Crucially, because the toy was offered in silence, these social
preferences were attributable to a preference for the individual who shared the
infant’s language, not for the language itself.
Similar findings emerged in a food-choice paradigm, in which infants were more
likely to choose a food offered by a speaker of their language than by a speaker of an-
other language (Shutts et al., 2009). Indeed, even objects similar to those depicted
in Figure 5.20 evoke social preferences (Hamlin et al., 2007). In a variation of the
“climber” procedure described above when infants as young as 6 months were pre-
sented with the objects they had just observed bumping the “climber” object up the
hill or pushing it down the hill, they tended to choose the “helper” object. The social
preferences exhibited in studies like these can be quite nuanced. In one recent study
that used puppets rather than objects, 5-month-olds uniformly preferred characters
who were positive toward “helpers,” whereas 8-month-olds preferred characters who
were positive toward “helpers” and negative toward “hinderers” (Hamlin et al., 2011).
These and related studies indicate that well before their 1st birthday, infants
have already learned a great deal about how humans behave and how their behavior
is related to their intentions and goals. Infants and young children can also draw
inferences about other people’s knowledge states. For example, 15-month-olds can
make inferences about what a person will do based on their knowledge of what the
person knows (Onishi & Baillargeon, 2005). In a visual-attention version of the
false-belief task (discussed in Chapter 4), infants seem to keep track of what in-
formation an adult has about the location of an object. If the object is moved to a
new location while an infant—but not the adult—witnesses the move, the infant
expects the adult to subsequently search for the object in its original location. That
is, the infant expects the adult to search where he or she should believe the toy to be,
rather than in the location where the infant knows it actually is. This interpreta-
tion is based on the fact that the infants looked longer when the adult searched the
object’s current location than they did when the adult searched its original loca-
tion. Thus, this study indicates that 15-month-olds assume that a person’s behavior
will be based on what the person believes to be true, even if the infant knows that
the belief is false. This result suggests that there may be very early precursors of a
theory of mind.
Looking Ahead
The intense activity focused on cognition in infancy has produced a wealth of fas-
cinating findings. This new information has not, however, resolved the basic issues
about how cognition develops in infancy. The evidence we have reviewed reveals a
remarkable constellation of abilities and deficits. Infants can be both surprisingly
smart and surprisingly clueless (Keen, 2003; Kloos & Keen, 2005). They can infer
the existence of an unseen object but cannot retrieve it. They appreciate that objects
cannot float in midair but think that any kind and amount of contact at all provides
sufficient support. The challenge for theorists is to account for both competence
and incompetence in infants’ thinking.
review:
Building on the insights and observations of Piaget, and using an array of extremely clever
methods, modern researchers have made a host of fascinating discoveries about the cogni-
tive processes of infants. They have demonstrated that infants mentally represent not only

212 n chapter 5 SEEING, THINKING, AND DOING IN INFANCY
the existence of hidden objects but also characteristics such as the object’s size, height,
and noise-making properties. Infants’ understanding of the physical world grows steadily, as
shown by their appreciation of support relations and their increasing ability to solve everyday
problems. At the same time, their understanding of the social world also increases, as shown,
for example, by their interpretation of and preferences concerning the behavior of actors, both
human and animated.
chapter summary:
Perception
n The human visual system is relatively immature at birth; young
infants have poor acuity, low contrast sensitivity, and minimal
color vision. Modern research has demonstrated, however,
that newborns begin visually scanning the world minutes after
birth and that very young infants show preferences for strongly
contrasted patterns, for the same colors that adults prefer, and,
especially, for human faces.
n Some visual abilities, including perception of constant size
and shape, are present at birth; others develop rapidly over
the first year. Binocular vision emerges quite suddenly at
around 4 months of age, and the ability to identify object
boundaries—object segregation—is also present at that age.
By 7 months, infants are sensitive to a variety of monocular,
or pictorial, depth cues; and pattern perception has developed
to the point that infants can perceive illusory (subjective)
contours, as adults do.
n The auditory system is comparatively well developed at birth,
and newborns will turn their heads to localize a sound. Young
infants’ remarkable proficiency at perceiving pattern in audi-
tory stimulation underlies their sensitivity to musical structure.
n Infants are sensitive to smell from birth. They learn to identify
their mother in part by her unique scent.
n Through active touching, using both mouth and hands, infants
explore and learn about themselves and their environment.
n Research on the phenomenon of intermodal perception has
revealed that from very early on, infants integrate information
from different senses, linking their visual with their auditory,
olfactory, and tactile experiences.
Motor Development
n Motor development, or the development of action, proceeds
rapidly in infancy through a series of “motor milestones,”
starting with the reflexes displayed by newborn babies. Recent
research has demonstrated that the regular pattern of develop-
ment results from the confluence of many factors, including
the development of strength, posture control, balance, and per-
ceptual skills. Some aspects of motor development vary across
cultures as a result of different cultural practices.
n Each new motor achievement, from reaching to self-
locomotion, expands the infant’s experience of the world but
also presents new challenges. Infants adopt a variety of strate-
gies to move around in the world successfully and safely. In the
process, they make a variety of surprising mistakes.
Learning
n Various kinds of learning are present in infancy. Infants habit-
uate to repeated stimuli and form expectancies about recur-
rent regularities in events. Through active exploration, they
engage in perceptual learning. They also learn through classical
conditioning, which involves forming associations between
natural and neutral stimuli as well as through instrumental
conditioning, which involves learning about the contingency
between one’s own behavior and some outcome. They can also
make use of prior experiences to generate expectations about
the future.
n From the second half of the first year on, observational
learning—watching and imitating the behavior of other
people—is an increasingly important source of information.
Infants’ assessment of the intention of a model affects what
they imitate.
Cognition
n Powerful new research techniques—most notably the
violation-of-expectancy procedure—have established that
infants display impressive cognitive abilities. Much of this
work on mental representation and thinking was originally
inspired by Piaget’s concept of object permanence. But it has
been revealed that, contrary to Piaget’s belief, young infants
can mentally represent invisible objects and even reason about
observed events.
n Other research, focused on infants’ developing knowledge of
the physical world, has demonstrated their understanding of
some of the effects of gravity. It takes babies several months to
work out the conditions under which one object can provide
stable support for another.
n What infants know about people is a very active area of
research. One clear finding is that infants pay particular atten-
tion to the intentions of others.

C H A P T E R S U M M A R Y n 213
n Although many fascinating phenomena have been dis-
covered in the area of infant cognition, basic issues about
cognitive development remain unresolved. Theorists are
sharply divided on how to account for the abilities, on the
one hand, and the deficiencies, on the other hand, in infants’
thinking.
Critical Thinking Questions
1. The major theme throughout this chapter was nature and
nurture. Consider the following research findings discussed
in the chapter: infants’ preference for consonance (versus
dissonance) in music, their preference for faces that adults
consider attractive, and their ability to represent the exis-
tence and even the height of an occluded object. To what
extent do you think these preferences and abilities rest on
innate factors, and to what extent might they be the result of
experience?
2. As you have seen from this chapter, researchers have learned
a substantial amount about infants in the recent past. Were
you surprised at some of what has been learned? Describe
to a friend something from each of the main sections of the
chapter that you would never have suspected an infant could
do or would know. Similarly, tell your friend a few things that
you were surprised to learn infants do not know or that they
fail to do.
3. Studying infants’ perceptual and cognitive abilities is espe-
cially tricky given their limited abilities to respond in a
study—they can’t respond verbally or even with a reliable
reach or point. Consider some of the methods described in
this chapter (preferential looking, conditioning, habitua-
tion, violation of expectation, imitation, and so on). Can you
match each method up with a study described in the chapter?
What kinds of questions are best suited to each method?
4. Explain why researchers did the following things, each of
which seems somewhat odd if one does not know the ratio-
nale behind it. What hypotheses were they trying to test?
(a) Suspended infants in water up to their waists
(b) Put a patch over one eye and showed infants a misshapen
window
(c) “Hid” a toy under a transparent container
(d) Pretended to be unable to pull the end off a dumbbell
Key Terms
affordances, p. 199
auditory localization, p. 182
binocular disparity, p. 181
classical conditioning, p. 201
conditioned response (CR), p. 201
conditioned stimulus (CS), p. 201
cones, p. 174
contrast sensitivity, p. 174
differentiation, p. 199
instrumental (or operant) conditioning, p. 201
intermodal perception, p. 186
monocular depth (or pictorial) cues, p. 181
object segregation, p. 179
optical expansion, p. 180
perception, p. 173
perceptual constancy, p. 178
positive reinforcement, p. 201
preferential-looking technique, p. 174
prereaching movements, p. 193
rational learning, p. 204
reflexes, p. 189
scale error, p. 196
self-locomotion, p. 194
sensation, p. 173
stepping reflex, p. 192
stereopsis, p. 181
unconditioned response (UCR), p. 201
unconditioned stimulus (UCS), p. 201
violation-of-expectancy, p. 206
visual acuity, p. 174

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N I C O L A B E A L I N G , Lucas Talking to a Dog, 2006 (oil on board)

215
Development of
Language and Symbol Use
n Language Development
The Components of Language
What Is Required for Language?
Box 6.1: Applications Two Languages Are Better
Than One
The Process of Language Acquisition
Box 6.2: Individual Differences The Role of Family and
School Context in Early Language Development
Box 6.3: Applications iBabies: Technology and
Language Learning
Theoretical Issues in Language Development
Box 6.4: A Closer Look “I Just Can’t Talk Without My
Hands”: What Gestures Tell Us About Language
Box 6.5: Individual Differences Developmental
Language Disorders
Review
n Nonlinguistic Symbols and Development
Using Symbols as Information
Drawing
Review
n Chapter Summary
chapter 6:

216
Themes
n Nature and Nurture
n The Active Child
n The Sociocultural Context
n Individual Differences
“Woof.” (used at age 11 months to refer to neighbor’s dog)
“Hot.” (used at age 14 months to refer to stove, matches, candles, light reflecting off
shiny surfaces, and so forth)
“Read me.” (used at age 21 months to ask mother to read a story)
“Why I don’t have a dog?” (27 months of age)
“If you give me some candy, I’ll be your best friend. I’ll be your two best friends.” (48
months of age)
“Granna, we went to Cagoshin [Chicago].” (65 months of age)
“It was, like, ya’ know, totally awesome, dude.” (192 months of age)
T
hese utterances were produced by one boy during the process of his
becoming a native English speaker (Clore, 1981). Each one reflects the
capacity that most sets humans apart from other species: the creative and
flexible use of symbols, which include language and many kinds of non-
linguistic symbols (print, numbers, pictures, models, maps, and so forth).
We use symbols (1) to represent our thoughts, feelings, and knowledge, and (2) to
communicate our thoughts, feelings, and knowledge to other people. Our ability to
use symbols vastly expands our cognitive and communicative power. It frees us from
the present, enabling us to learn from the generations of people who preceded us and
to contemplate the future. Becoming symbol-minded is a crucial developmental task
for children around the world (DeLoache, 2005).
In this chapter, we will focus primarily on the acquisition of
the preeminent symbol system: language. We will then discuss
children’s understanding and creation of nonlinguistic symbols,
such as pictures and models.
The dominant theme in this chapter will once again be the
relative contributions of nature and nurture. A related issue con-
cerns the extent to which language acquisition is made possi-
ble by abilities that are specialized for language learning versus
general- purpose mechanisms that support all sorts of learning.
The sociocultural context is another prominent theme and fea-
tures research that examines differences in language acquisition
across cultures and communities. This comparative work often
provides evidence that is crucial to various theories of language
development.
A third recurring theme is individual differences. For any given
language milestone, some children will achieve it much earlier,
and some much later, than others. The active child theme also
puts in repeated appearances. Infants and young children pay
close attention to language and a wide variety of other symbols, and they work hard
at figuring out how to use them to communicate.
Language Development
What is the average kindergartener almost as good at as you are? Not much, with
one important exception: using language. By 5 years of age, most children have
mastered the basic structure of their native language or languages (the possibility
of bilingualism is to be assumed whenever we refer to “native language”), whether
spoken or manually signed. Although their vocabulary and powers of expression are
These children are intent on mastering one
of the many important symbol systems in
the modern world.
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symbols n systems for representing our
thoughts, feelings, and knowledge and for
communicating them to other people

L A N G U A G E D E V E L O P M E N T n 217
less sophisticated than yours, their sentences are as grammatically correct as those
produced by the average college student. This is a remarkable achievement.
Language use requires comprehension, which refers to understanding what oth-
ers say (or sign or write), and production, which refers to actually speaking (or sign-
ing or writing). As we have observed for other areas of development, infants’ and
young children’s ability to understand precedes their ability to produce. Children un-
derstand words and linguistic structures that other people use months or even years
before they include them in their own utterances. This is, of course, not unique to
young children; you no doubt understand many words that you never actually use.
In our discussion, we will be concerned with the developmental processes involved
in both comprehension and production, as well as the relation between them.
The Components of Language
How do languages work? Despite the fact that there are thousands of human
languages, they share overarching similarities. All human languages are similarly
complex, with different pieces combined at different levels to form a hierarchy:
sounds are combined to form words, words are combined to form sentences, and
sentences are combined to form stories, conversations, and other kinds of narra-
tives. Children must acquire all of these facets of their native language. The enor-
mous benefit that emerges from this combinatorial process is generativity; by
using the finite set of words in our vocabulary, we can generate an infinite number
of sentences, expressing an infinite number of ideas.
However, the generative power of language carries a cost for young language
learners: they must deal with its complexity. To appreciate the challenge presented
to children learning their first language, imagine yourself as a stranger in a strange
land. Someone walks up to you and says, “Jusczyk daxly blickets Nthlakapmx.” You
would have absolutely no idea what this person had just said. Why?
First, you would probably have difficulty perceiving some of the phonemes that
make up what the speaker is uttering. Phonemes are the units of sound in speech; a
change in phoneme changes the meaning of a word. For example, “rake” and “lake”
differ by only one phoneme (/r/ versus /l/), but the two words have quite different
meanings to English speakers. Different languages employ different sets of pho-
nemes; English uses just 45 of the roughly 200 sounds found across the world’s lan-
guages. The phonemes that distinguish meaning in any one language overlap with,
but also differ from, those in other languages. For example, the sounds /r/ and /l/
are a single phoneme in Japanese, and do not carry different meanings. Further-
more, combinations of sounds that are common in one language may never occur
in others. When you read the stranger’s utterance in the preceding paragraph, you
probably had no idea how to pronounce the word Nthlakapmx, because some of
its sound combinations do not occur in English (though they do occur in other
languages). Thus, the first step in children’s language learning is phonological
development: the mastery of the sound system of their language.
Another reason you would not know what the stranger had said to you, even if
you could have perceived the sounds being uttered, is that you would have had no
idea what the sounds mean. The smallest units of meaning are called morphemes.
Morphemes, alone or in combination, constitute words. The word dog, for example,
contains one morpheme. The word dogs contains two morphemes, one designating
a familiar furry entity (dog) and the second indicating the plural (-s). Thus, the sec-
ond component in language acquisition is semantic development, that is, learning
the system for expressing meaning in a language, including word learning.
comprehension n with regard to lan-
guage, understanding what others say (or
sign or write)
production n with regard to language,
speaking (or writing or signing) to others
generativity n refers to the idea that
through the use of the finite set of words
and morphemes in humans’ vocabulary,
we can put together an infinite number of
sentences and express an infinite number
of ideas
phonemes n the elementary units
of meaningful sound used to produce
languages
phonological development n the
acquisition of knowledge about the sound
system of a language
morphemes n the smallest units of
meaning in a language, composed of one
or more phonemes
semantic development n the learning
of the system for expressing meaning in a
language, including word learning

218 n chapTer 6 DEVELOPMENT OF LANGUAGE AND SYMBOL USE
However, even if you were told the meaning of each individual word the
stranger had used, you would still not understand the utterance unless you knew
how words are put together in the stranger’s language. To express an idea of any
complexity, we combine words into sentences, but only certain combinations are
allowed in any given language. Syntax refers to the permissible combinations of
words from different categories (nouns, verbs, adjectives, etc.). In English, for ex-
ample, the order in which words can appear in a sentence is crucial: “Lila ate the
lobster” does not mean the same thing as “The lobster ate Lila.” Other languages
indicate which noun did the eating and which noun was eaten by adding mor-
phemes like suffixes to the nouns. For example, a Russian noun ending in “a” is
likely to refer to the entity doing the eating, while the same noun ending in “u”
is likely to refer to the thing that was eaten. The third component in language
learning, then, is syntactic development, that is, learning how words and mor-
phemes are combined.
Finally, a full understanding of the interaction with the stranger would necessi-
tate having some knowledge of the cultural rules and contextual variations for using
language. In some societies, for example, it would be quite bizarre to be addressed
by a stranger in the first place, whereas in others it would be commonplace. You
would also need to know how to go beyond the speaker’s specific words to under-
stand what the speaker was really trying to communicate—to use factors such as
the context and the speaker’s emotional tone to read between the lines and to learn
how to hold a conversation. Acquiring an understanding of how language is typi-
cally used is referred to as pragmatic development.
Our example of the bewilderment one experiences when listening to an unfa-
miliar language is useful for delineating the components of language use. However,
when we, as adults, hear someone speaking an unfamiliar language, we already
know what a language is. We know that the sounds the person is uttering constitute
words, that words are combined to form sentences, that only certain combinations
are acceptable, and so on. In other words, in contrast with
young language learners, adults have considerable meta­
linguistic knowledge—that is, knowledge about language
and its properties.
Thus, learning language involves phonological, seman-
tic, syntactic, and pragmatic development, as well as meta-
linguistic knowledge. The same factors are involved in
learning a sign language, in which the basic linguistic el-
ements are gestures rather than sounds. There are more
than 200 languages, including American Sign Language
(ASL), that are based on gestures, both manual and facial.
They are true languages and are as different from one an-
other as spoken languages are. The course of acquisition of
a sign language is remarkably similar to that of a spoken
language.
What Is Required for Language?
What does it take to be able to learn a language in the first place? Full-fledged
language is achieved only by humans, so, obviously, one requirement is the human
brain. But a single human, isolated from all sources of linguistic experience, could
never learn a language; hearing (or seeing) language is a crucial ingredient for suc-
cessful language development.
By the age of 5, children are capable of gen-
erating totally novel sentences that are cor-
rect in terms of the phonology, semantics,
and syntax of their native language. They
are also able to make appropriate pragmatic
inferences regarding the content of their
partner’s utterances.
U
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syntax n rules in a language that specify
how words from different categories
(nouns, verbs, adjectives, and so on) can
be combined
syntactic development n the learning
of the syntax of a language
pragmatic development n the acqui-
sition of knowledge about how language
is used
metalinguistic knowledge n an under-
standing of the properties and function
of language—that is, an understanding of
language as language

L A N G U A G E D E V E L O P M E N T n 219
A Human Brain
The key to full-fledged language development lies in the human brain. Language
is a species-specific behavior: only humans acquire language in the normal course of
development. Furthermore, it is species-universal: language learning is achieved by
typically developing infants across the globe.
In contrast, no other animals naturally develop anything approaching the com-
plexity or generativity of human language, even though they can communicate with
one another. For example, birds claim territorial rights by singing (Marler, 1970),
and vervet monkeys can reveal the presence and identity of predators through spe-
cific calls (Seyfarth & Cheney, 1993).
Researchers have had limited success in training nonhuman primates to use
complex communicative systems. One early effort was an ambitious project in
which a dedicated couple raised a chimpanzee (Vicki) with their own children
(Hayes & Hayes, 1951). Although Vicki learned to comprehend some words and
phrases, she produced virtually no recognizable words. Subsequent researchers
attempted to teach nonhuman primates sign language. Washoe, a chimpanzee,
and Koko, a gorilla, became famous for their ability to communicate with their
human trainers and caretakers using manual signs (Gardner & Gardner, 1969;
Patterson & Linden, 1981). Washoe could label a variety of objects and could
make requests (“more fruit,” “please tickle”). The general consensus is that, how-
ever impressive Washoe’s and Koko’s “utterances” were, they do not qualify as
language, because they contained little evidence of syntactic structure (Terrace et
al., 1979; Wallman, 1992).
The most successful sign-learning nonhuman is Kanzi, a great ape of the bonobo
species. Kanzi’s sign-learning began when he observed researchers trying to teach
his mother to communicate with them by using a lexigram board, a panel composed
of a few graphic symbols representing specific objects and actions (“give,” “eat,” “ba-
nana,” “hug,” and so forth) (Savage-Rumbaugh et al., 1993). Kanzi’s mother never
caught on, but Kanzi did, and over the years his lexigram vocabulary increased from
6 words to more than 350. He is now very adept at using his lexigram board to
answer questions, to make requests, and even to offer comments. He often com-
bines signs, but whether they can be considered syntactically structured sentences
is not clear.
There are also several well-documented cases of nonprimate animals that have
learned to respond to spoken language. Kaminski, Call, and Fischer (2004) found
that Rico, a border collie, knew more than 200 words and could learn and remem-
ber new words using the same kinds of processes that toddlers use
(see pages 236–237). Alex, an African Grey parrot, learned to pro-
duce and understand basic English utterances, although his skills
remained at a toddler level (Pepperberg, 1999).
Whatever the ultimate decision regarding the extent to which
trained nonhuman animals should be credited with language, sev-
eral things are clear. Even their most basic linguistic achievements
come only after a great deal of concentrated human effort, whereas
human children master the rudiments of their language with little
explicit teaching. Furthermore, while the most advanced nonhu-
man communicators do combine symbols, their utterances show
limited evidence of syntactic structure, which is a defining feature
of language (Tomasello, 1994). In short, only the human brain
acquires a communicative system with the complexity, structure,
and generativity of language. Correspondingly, we humans are
Kanzi, a bonobo chimpanzee, and his care-
takers communicate with one another by
using a specially designed set of symbols
that stand for a wide variety of objects,
people, and actions.
LA
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This photo shows rico demonstrating his
language comprehension by fetching spe-
cific toys on request.
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220 n chapTer 6 DEVELOPMENT OF LANGUAGE AND SYMBOL USE
notoriously poor at learning the communicative systems of other species (Harry
Potter’s ability to speak Parseltongue with snakes aside). There is an excellent
match between the brains of animals of different species and their respective com-
municative systems.
Brain–language relations A vast amount of research has examined the relation-
ship between language and brain function. It is clear that language processing in-
volves a substantial degree of functional localization. At the broadest level, there are
hemispheric differences in language functioning that we discussed to some extent
in Chapter 3. For the 90% of people who are right-handed, language is primarily
represented and controlled by the left hemisphere.
Left-hemisphere specialization appears to emerge very early in life. Studies
using neuroimaging techniques have demonstrated that newborns and 3-month-
olds show greater activity in the left hemisphere when exposed to normal speech
than when exposed to reversed speech or silence (Bortfeld, Fava, & Boas, 2009;
Dehaene-Lambertz, Dehaene, & Hertz-Pannier, 2002; Pena et al., 2003). In addi-
tion, EEG studies show that infants exhibit greater left-hemisphere activity when
listening to speech but greater right-hemisphere activity when listening to non-
speech sounds (Molfese & Betz, 1988). An exception to this pattern of lateraliza-
tion occurs in the detection of pitch in speech, which in infants, as in adults, tends
to involve the right hemisphere (Homae et al., 2006).
Although it is evident that the left hemisphere predominantly processes speech
from birth, the reasons for this are not yet known. One possibility is that the left
hemisphere is innately predisposed to process language but not other auditory
stimuli. Another possibility is that speech is localized to the left hemisphere be-
cause of its acoustic properties. In this view, the auditory cortex in the left hemi-
sphere is tuned to detect small differences in timing, whereas the auditory cortex in
the right hemisphere is tuned to detect small differences in pitch (e.g., Zatorre et
al., 1992; Zatorre & Belin, 2001; Zatorre, Belin, & Penhune, 2002). Because speech
turns on small differences in timing (as you will see when we discuss voice onset
time, page 225), it may be a more natural fit for the left hemisphere.
critical period for language development If you were to survey your classmates
who have studied another language, we predict you would discover that those who
learned a foreign language in adolescence found the task to be much more chal-
lenging than did those who learned the foreign language in early childhood. A
considerable body of evidence suggests that, in fact, the early years constitute a crit­
ical period during which language develops readily. After this period (which ends
sometime between age 5 and puberty), language acquisition is much more difficult
and ultimately less successful.
Relevant to this hypothesis, there are several reports of children who barely de-
veloped language at all after being deprived of early linguistic experience. The most
famous case in modern times is Genie, who was discovered in appalling conditions
in Los Angeles in 1970. From the age of approximately 18 months until she was
rescued at age 13, Genie’s parents kept her tied up and locked alone in a room.
During her imprisonment, no one spoke to her; when her father brought her food,
he growled at her like an animal. At the time of her rescue, Genie’s development
was stunted—physically, motorically, and emotionally—and she could barely speak.
With intensive training, she made some progress, but her language ability never
developed much beyond the level of a toddler’s: “Father take piece wood. Hit. Cry”
(Curtiss, 1977, 1989; Rymer, 1993).
critical period for language n the
time during which language develops
readily and after which (sometime
between age 5 and puberty) language
acquisition is much more difficult and
ultimately less successful

L A N G U A G E D E V E L O P M E N T n 221
Does this extraordinary case support the critical-period hypothesis?
Possibly, but it is difficult to know for sure. Genie’s failure to develop
full, rich, language after her discovery might have resulted as much
from the bizarre and inhumane treatment she suffered as from linguistic
deprivation.
Other areas of research provide much stronger evidence for the
critical- period hypothesis. As noted in Chapter 3, adults, who are well
beyond the critical period, are more likely to suffer permanent language
impairment from brain damage than are children, presumably because
other areas of the young brain (but not the older brain) are able to take
over language functions (see M. H. Johnson, 1998). Moreover, adults
who learned a second language after puberty use different neural mecha-
nisms to process that language than do adults who learned their second
language from infancy (e.g., Kim et al., 1997; Pakulak & Neville, 2011).
These results strongly suggest that the neural circuitry supporting lan-
guage learning operates differently (and better) during the early years.
In an important behavioral study, Johnson and Newport (1989) tested the En-
glish proficiency of Chinese and Korean immigrants to the United States who had
begun learning English either as children or as adults. The results, shown in Figure
6.1, reveal that knowledge of key aspects of English grammar was related to the age
at which these individuals began learning English, but not to the length of their
exposure to the language. The most proficient were those who had begun learning
English before the age of 7.
A similar pattern has been described for first-language acquisition in the Deaf
community: individuals who acquired ASL as a first language when they were chil-
dren become more proficient signers than do individuals who acquired ASL as a
first language as teens or adults (Newport, 1990). Johnson and Newport also ob-
served a great deal of variability among “late learners”—those who were acquiring
a second language, or a sign language as their first formal language, at puberty or
beyond. As in the findings we predicted for your survey of classmates, some indi-
viduals achieved nativelike skills, whereas the language outcomes for others were
quite poor. For reasons that are still unknown, some individuals continue to be tal-
ented language learners even after puberty, while most do not.
Newport (1990) proposed an intriguing hypothesis to explain these results and,
more generally, to explain why children are usually better language learners than
adults. According to her “less is more” hypothesis, perceptual and memory limita-
tions cause young children to extract and store smaller chunks of the language than
adults do. Because the crucial building blocks of language (the meaning-carrying
morphemes) tend to be quite small, young learners’ limited cognitive abilities may
actually facilitate the task of analyzing and learning language.
The evidence for a critical period in language acquisition has some very clear
practical implications. For one thing, deaf children should be exposed to sign lan-
guage as early as possible. For another, foreign-language exposure at school, dis-
cussed in Box 6.1, should begin in the early grades in order to maximize children’s
opportunity to achieve native-level skills in a second language.
A Human Environment
Possession of a human brain is not enough for language to develop. Children must
also be exposed to other people using language—any language, signed or spoken.
Adequate experience hearing others talk is readily available in the environment
Native 8–10 11–15 17–39 3–7
Age (in years) at arrival
270
260
250
240
230
220
210
M
ea
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s
co
re

FIGURE 6.1 Test of critical-period
hypothesis performance on a test of
en glish grammar by adults originally from
Korea and china was directly related to the
age at which they came to the United States
and were first exposed to english. The
scores of adults who emigrated before the
age of 7 were indistinguishable from those
of native speakers of english. (adapted from

222 n chapTer 6 DEVELOPMENT OF LANGUAGE AND SYMBOL USE
The topic of bilingualism, the ability to use
two languages, has attracted substantial at-
tention in recent years as increasing num-
bers of children are developing bilingually.
Indeed, almost half the children in the
world are regularly exposed to more than
one language, often at home with parents
who speak different languages. Remark-
ably, despite the fact that bilingual children
have twice as much to learn as monolingual
children, they show little confusion and lan-
guage delay. In fact, there is evidence to
suggest that being bilingual improves as-
pects of cognitive functioning in childhood
and beyond.
Bilingual learning can begin in the womb.
Newborns prenatally exposed to just their
native language prefer it over other lan-
guages, whereas newborns whose mothers
spoke two languages during pregnancy pre-
fer both languages equally (Byers- Heinlein,
Burns, & Werker, 2010). Bilingual infants
are able to discriminate the speech sounds
of their two languages at roughly the same
pace that monolingual infants distinguish
the sounds of their one language (e.g.,
Albareda-Castellot, Pons, & Sebastián-
Gallés, 2011; Sundara, Polka, & Molnar,
2008). How might this be, given that bilin-
gual infants have twice as much to learn?
One possibility is that bilinguals’ attention
to speech cues is heightened relative to that
of monolinguals. For example, bilingual in-
fants are better than monolingual infants at
using purely visual information (a silent talk-
ing face) to discriminate between unfamiliar
languages (Sebastián-Gallés et al., 2012).
For the most part, children who are ac-
quiring two languages do not seem to con-
fuse them; indeed, they appear to build
two separate linguistic systems. When lan-
guage mixing does occur, it usually reflects
a gap of knowledge in one language that the
child is trying to fill in with the other, rather
than a confusing of the two language sys-
tems (e.g., Deuchar & Quay, 1999; Paradis,
Nicoladis, & Genesee, 2000).
Children developing bilingually may ap-
pear to lag behind slightly in each of their
languages because their vocabulary is dis-
tributed across two languages (Oller &
Pearson, 2002). That is, a bilingual child
may know how to express some concepts in
one language but not the other. However,
both the course and the rate of language de-
velopment are generally very similar for bi-
lingual and monolingual children (Genesee
& Nicoladis, 2006). And as we have noted,
there are cognitive benefits to bilingual-
ism: children who are competent in two
languages perform better on a variety of
measures of executive function and cogni-
tive control than do monolingual children
(Bialystok & Craik, 2010; Costa, Hernandez,
& Sebastián- Gallés, 2008). Recent results
reveal similar effects for bilingual toddlers
(Poulin-Dubois et al., 2011). Even bilin-
gual infants appear to show greater cogni-
tive flexibility in learning tasks (Kovács &
Mehler, 2009a, b). The link between bilin-
gualism and improved cognitive flexibility
likely lies in the fact that bilingual individu-
als have had to learn to rapidly switch be-
tween languages, both in comprehension
and production.
More difficult issues arise with respect to
second-language learning in the school set-
ting. Some countries with large but distinct
language communities, like Canada, have
embraced bilingual education. Others, in-
cluding the United States, have not. The de-
bate over bilingual education in the United
States is tied up with a host of political,
ethnic, and racial issues. One side of this
debate advocates total immersion, in which
children are communicated with and taught
exclusively in English, the goal being to
help them become proficient in English as
quickly as possible. The other side recom-
mends an approach that initially provides
children with instruction in basic subjects
in their native language and gradually in-
creases the amount of instruction provided
in English (Castro et al., 2011).
In support of the latter view, there is evi-
dence that (1) children often fail to master
basic subject matter when it is taught in a
language they do not fully understand; and
(2) when both languages are integrated in
the classroom, children learn the second lan-
guage more readily, participate more actively,
and are less frustrated and bored (August &
Hakuta, 1998; Crawford, 1997; Hakuta,
1999). This approach also helps prevent sit-
uations where children might become less
proficient in their original language as a re-
sult of being taught a second one in school.
BOX 6.1: applications
TWO LANGUAGES ARE BETTER THAN ONE
The issue of bilingualism in the classroom has
been a topic of intense debate in the United
States and other parts of the world. how-
ever, research conducted by ellen Bialystok
in canada, where a substantial proportion of
the population is bilingual, reveals a variety of
benefits of proficiency in multiple languages.
P
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L A N G U A G E D E V E L O P M E N T n 223
of almost all children around the world. Much of the speech directed to infants
occurs in the context of daily routines—during thousands of mealtimes, diaper
changes, baths, and bedtimes, as well as in countless games like peekaboo and nurs-
ery rhymes like the “Itsy Bitsy Spider.”
Infants identify speech as something important very early. When given the choice,
newborns prefer listening to speech rather than to artificial sounds (Vouloumanos
et al., 2010). Intriguingly, newborns also prefer nonhuman primate (rhesus ma-
caque) vocalizations to nonspeech sounds, and show no preference for speech over
macaque vocalizations until 3 months of age (Vouloumanos et al., 2010). These re-
sults suggest that infants’ auditory preferences are fine-tuned through experience
with human language during their earliest months.
Infant-directed speech Imagine yourself on a bus listening
to a stranger who is seated behind you and speaking to some-
one. Could you guess whether the stranger was addressing an
infant or an adult? We have no doubt that you could, even if the
stranger was speaking an unfamiliar language. The reason is that
in virtually all cultures, adults adopt a distinctive mode of speech
when talking to babies and very young children. This special way
of speaking was originally dubbed “motherese” (Newport, Glei-
tman, & Gleitman, 1977). The current term, infant­directed
speech (IDS), recognizes the fact that this style of speech is used
by both males and females, including parents and nonparents
alike. Indeed, even young children adopt it when talking to ba-
bies (Shatz & Gelman, 1973).
CHARACTERISTICS OF INFANT-DIRECTED SPEECH The most obvious quality of IDS is its
emotional tone. It is speech suffused with affection—“the sweet music of the spe-
cies,” as Darwin (1877) put it. Another obvious characteristic of IDS is exaggeration.
When people speak to babies, their speech is slower, and their voice is often higher
pitched, than when they speak to adults, and they swoop abruptly from high pitches
to low pitches and back again. Even their vowels are clearer (Kuhl et al., 1997). All
this exaggerated speech is accompanied by exaggerated facial expressions. Many of
these characteristics have been noted in adults speaking such languages as Arabic,
French, Italian, Japanese, Mandarin Chinese, and Spanish (see de Boysson-Bardies,
1996/1999), as well as in deaf mothers signing to their infants (Masataka, 1992).
Beyond expressing emotional tone, caregivers can use various pitch patterns
of IDS to communicate important information to infants even when infants
don’t know the meaning of the words uttered. For example, a word uttered with
sharply falling intonation tells the baby that their caregiver disapproves of some-
thing, whereas a cooed warm sound indicates approval. These pitch patterns
serve the same function in language communities ranging from English and
Italian to Japanese (Fernald et al., 1989). Interestingly, infants exhibit appropri-
ate facial emotion when listening to these pitch patterns, even when the lan-
guage is unfamiliar (Fernald, 1993).
IDS also seems to aid infants’ language development. To begin with, it draws in-
fants’ attention to speech itself. Indeed, infants prefer IDS to adult-directed speech
(Cooper & Aslin, 1994; Pegg, Werker, & McLeod, 1992), even when it is in a lan-
guage other than their own. For example, both Chinese and American infants lis-
tened longer to a recording of a Cantonese-speaking woman talking to a baby in
IDS than to the same woman speaking normally to an adult friend (Werker, Pegg, &
McLeod, 1994). Some studies suggest that infants’ preference for IDS may emerge
The infant-directed talk used by this father
grabs and holds his baby’s attention.
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bilingualism n the ability to use two
languages
infant-directed speech (IDS) n the
distinctive mode of speech that adults
adopt when talking to babies and very
young children

224 n chapTer 6 DEVELOPMENT OF LANGUAGE AND SYMBOL USE
because it is “happy speech”; when speakers’ affect is held constant, the pref-
erence disappears (Singh, Morgan, & Best, 2002). Perhaps because they pay
greater attention to IDS, infants learn and recognize words better when the
words are presented in IDS than when they are presented in adult-directed
speech (Ma et al., 2011; Singh et al., 2009; Thiessen, Hill, & Saffran, 2005).
Although IDS is very common throughout the world, it is not universal.
In some cultures, such as the Kwara’ae of the Solomon Islands, the Ifaluk of
Micronesia, and the Kaluli of Papua New Guinea, it is believed that because
infants cannot understand what is said to them, there is no reason for caregiv-
ers to speak to them (Le, 2000; Schieffelin & Ochs, 1987; Watson-Gegeo, &
Gegeo, 1986). For example, young Kaluli infants are carried facing outward
so that they can engage with other members of the group (but not with their
caregiver), and if they are spoken to by older siblings, the mother will speak
for them (Schieffelin & Ochs, 1987). Thus, even if they are not addressed
directly by their caregivers, these infants are still immersed in language.
That infants begin life equipped with the two basic necessities for acquir-
ing language—a human brain and a human environment—is, of course, only
the beginning of the story. Of all the things we learn as humans, languages
are arguably the most complex; so complex, in fact, that scientists have yet
to be able to program computer systems to acquire a human language. The
overwhelming complexity of language is further reflected in the difficulty
most people have in learning a new language after puberty. How, then, do
infants and young children manage to acquire their native language with such as-
tounding success? We turn now to the many steps through which that remarkable
accomplishment proceeds.
The Process of Language Acquisition
Acquiring a language involves listening and speaking (or watching and signing)
and requires both comprehending what other people communicate and producing
intelligible speech (or signs). Infants start out paying attention to what people say
or sign, and they know a great deal about language long before their first linguistic
productions.
Speech Perception
The first step in language learning is figuring out the sounds of one’s native lan-
guage. As you saw in Chapter 2, the task usually begins in the womb, as fetuses
develop a preference for their mother’s voice and the language they hear her speak.
The basis for this very early learning is prosody, the characteristic rhythmic and
intonation patterns with which a language is spoken. Differences in prosody are in
large part responsible for why languages—from Japanese to French to Swahili—
sound so different from one another.
Speech perception also involves distinguishing among the speech sounds that
make a difference in a given language. To learn English, for example, one must dis-
tinguish between bat and pat, dill and kill, Ben and bed. As you will see next, young
infants do not have to learn to hear these differences: they perceive many speech
sounds in very much the same way that adults do.
categorical perception of speech sounds Both adults and infants perceive
speech sounds as belonging to discrete categories. This phenomenon, referred to
as categorical perception, has been established by studying people’s response to
around the world, parents in some cultures
talk directly to their babies, whereas parents
in other cultures do not. almost everywhere,
adults and older children use some form of
“baby talk” to address infants.
JO
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prosody n the characteristic rhythm,
tempo, cadence, melody, intonational pat-
terns, and so forth with which a language
is spoken
categorical perception n the percep-
tion of speech sounds as belonging to dis-
crete categories

L A N G U A G E D E V E L O P M E N T n 225
speech sounds. In this research, a speech synthesizer is used to gradually and con-
tinuously change one speech sound, such as /b/, into a related one, such as /p/. These
two phonemes are on an acoustic continuum; they are produced in exactly the same
way, except for one crucial difference—the length of time between when air passes
through the lips and when the vocal cords start vibrating. This lag, referred to as
voice onset time (VOT), is shorter for /b/ (less than 25 milliseconds [ms]) than
for /p/ (greater than 25 ms). (Try saying “ba” and “pa” alternately several times, with
your hand on your throat, and you will likely experience this difference in VOT.)
To study the perception of VOT, researchers create recordings of speech sounds
that vary along this VOT continuum, so that each successive sound is slightly dif-
ferent from the one before, with /b/ gradually changing into /p/. What is surprising
is that adult listeners do not perceive this continuously changing series of sounds
(Figure 6.2). Instead, they hear /b/ repeated several times and then hear an abrupt
switch to /p/. All the sounds in this continuum that have a VOT of less than 25 ms
are perceived as /b/, and all those that have a VOT greater than 25 ms are perceived
as /p/. Thus, adults automatically divide the continuous signal into two discontinu-
ous categories—/b/ and /p/. This perception of a continuum as two categories is a
very useful perceptual ability because it allows one to pay attention to sound differ-
ences that are meaningful in one’s native language, such as, in English, the difference
between /b/ and /p/, while allowing meaningless differences, such as the difference
between a /b/ with a 10 ms VOT versus a /b/ with a 20 ms VOT, to be ignored.
Young infants draw the same sharp distinctions between speech sounds. This re-
markable fact was established using the habituation technique familiar to you from
previous chapters. In the original, classic study (one of the 100 most frequently
cited studies in psychology), 1- and 4-month-olds sucked on a pacifier hooked up
to a computer (Eimas et al., 1971). The harder they sucked, the more often they’d
hear repetitions of a single speech sound. After hearing the same sound repeatedly,
the babies gradually sucked less enthusiastically (habituation). Then a new sound
was played. If the infants’ sucking rate increased in response to the new sound, the
researchers inferred that the infants discriminated the new sound from the old one
(dishabituation).
The crucial factor in this study was the relation between the new and old
sounds—specifically, whether they were from the same or different phonemic cat-
egories. For one group of infants, the new sound was from a different category;
–10 10 20 30 40 50 60 70 0 –50 –40 –30 –20
Voice onset time (ms)
100
80
60
40
20
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/pa/
/ba/ FIGURE 6.2 categorical perception
of speech sounds by adults When adults
listen to a tape of artificial speech sounds
that gradually change from one sound to
another, such as /ba/ to /pa/ or vice versa,
they suddenly switch from perceiving one
sound to perceiving the other. (adapted from
voice onset time (VOT) n the length
of time between when air passes through
the lips and when the vocal cords start
vibrating

226 n chapTer 6 DEVELOPMENT OF LANGUAGE AND SYMBOL USE
thus, after habituation to a series of sounds that adults
perceive as /b/, sucking now produced a sound that adults
identify as /p/. For the second group, the new sound was
within the same category as the old one (i.e., adults per-
ceive them both as /b/). A critical feature of the study is
that for both groups, the new and old sounds differed
equally in terms of VOT.
As Figure 6.3 shows, after habituating to /b/, the in-
fants increased their rate of sucking when the new sound
came from a different phonemic category (/p/ instead
of /b/). Habituation continued, however, when the new
sound was within the same category as the original one.
Since this classic study, researchers have established that
infants show categorical perception of numerous speech
sounds (Aslin, Jusczyk, & Pisoni, 1998).
A fascinating outcome of this research is the discovery
that young infants actually make more distinctions than
adults do. This rather surprising phenomenon occurs because any given language
uses only a subset of the large variety of phonemic categories that exist. As noted
earlier, the sounds /r/ and /l/ make a difference in English, but not in Japanese.
Similarly, speakers of Arabic, but not of English, perceive a difference between the
/k/ sounds in “keep” and “cool.” Adults simply do not perceive differences in speech
sounds that are not important in their native language, which partly accounts for
why it is so difficult for adults to become fluent in a second language.
In contrast, infants can distinguish between phonemic contrasts made in all
the languages of the world—about 600 consonants and 200 vowels. For example,
Kikuyu infants in Africa are just as good as American babies at discriminating
English contrasts not found in Kikuyu (Streeter, 1976). Studies done with infants
from English-speaking homes have shown that they can discriminate non-English
distinctions made in languages ranging from German and Spanish to Thai, Hindi,
and Zulu ( Jusczyk, 1997).
This research reveals an ability that is innate, in the sense that it is present at
birth, and experience-independent, because infants can discriminate between speech
sounds they have never heard before. Being born able to distinguish speech sounds
of any language is enormously helpful to infants, priming them to start learning
whichever of the world’s languages they hear around them. Indeed, the crucial role
of early speech perception is reflected in a positive correlation between infants’
speech-perception skills and their later language skills. Babies who were better at
detecting differences between speech sounds at 6 months scored higher on measures
of vocabulary and grammar at 13 to 24 months of age (Tsao, Liu, & Kuhl, 2004).
Developmental changes in speech perception During the last months of their
first year, infants increasingly home in on the speech sounds of their native lan-
guage, and by 12 months of age, they have “lost” the ability to perceive the speech
sounds that are not part of it. In other words, their speech perception has become
adultlike. This shift was first demonstrated by Werker and her colleagues (Werker,
1989; Werker & Lalonde, 1988; Werker & Tees, 1984), who studied infants rang-
ing in age from 6 to 12 months. The infants, all from English-speaking homes, were
tested on their ability to discriminate speech contrasts that are not used in English
but that are important in two other languages—Hindi and Nthlakapmx (a language
spoken by indigenous First Nations people in the Canadian Pacific Northwest).
Time (min)
M
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m
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su
ck
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re
sp
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se
s
4 3 2 1 1 2 3 4 5 B
60
45
30
15
4 3 2 1 1 2 3 4 5 B
VOT = 20 VOT = 60 VOT = 80 VOT = 40
(a) (b) (c) (d)
FIGURE 6.3 categorical perception of
speech sounds by infants Infants aged
1 to 4 months were habituated to a tape
of artificial speech sounds. (a) One group
repeatedly heard a /ba/ sound with a VOT of
20, and they gradually habituated to it. (b)
When the sound changed to /pa/, with a VOT
of 40, they dishabituated, indicating that
they perceived the difference between the
two sounds, just as adults do. (c) a different
group was habituated to a /pa/ sound with a
VOT of 60. (d) When the sound changed to
another /pa/ with a VOT of 80, the infants
remained habituated, suggesting that, like
adults, they did not discriminate between
these two sounds. (adapted from eimas et

L A N G U A G E D E V E L O P M E N T n 227
The researchers used a simple conditioning procedure, shown in Figure 6.4. The
infants learned that if they turned their head toward the sound source when they
heard a change in the sounds they were listening to, they would be rewarded by an
interesting visual display. If the infants turned their heads in the correct direction
immediately following a sound change, the researchers inferred that they had de-
tected the change.
Figure 6.5 shows that at 6 to 8 months of age, English-learning infants readily
discriminated between the sounds they heard; they could tell one Hindi syllable
from another, and they could also distinguish between two sounds in Nthlakapmx.
At 10 to 12 months of age, however, the infants no longer perceived the differences
they had detected a few months before. Two Hindi syllables that had previously
sounded different to them now sounded the same. Other research indicates that a
similar change occurs slightly earlier for the discrimination of vowels (Kuhl et al.,
1992; Polka & Werker, 1994). Interestingly, this perceptual narrowing does not ap-
pear to be an entirely passive process. Kuhl, Tsao, and Liu (2003) found that infants
learned more about the phonetic structure of Mandarin from a live interaction with
a Mandarin speaker than from watching a videotape of one.
Is this process of perceptual narrowing limited to speech? To answer this ques-
tion, a recent study asked whether this narrowing process also occurs in ASL
(Palmer et al., 2012). The researchers began by determining whether infants who
had never been exposed to ASL were able to discriminate between highly simi-
lar ASL signs that are differentiated by the shape of the hand. They found that
4-month-olds could, in fact, discriminate between the signs. However, by 14
months of age, only infants who were learning ASL were able to detect the dif-
ference between the hand shapes; those who were not learning ASL had lost their
ability to make this perceptual discrimination. Perceptual narrowing is thus not
limited to speech. Indeed, this narrowing process may be quite broad; recall the dis-
cussion of perceptual narrowing in the domains of face perception (page 185) and
musical rhythm (page 184) discussed in Chapter 5.
Thus, after the age of 8 months or so, infants begin to specialize in their dis-
crimination of speech sounds, retaining their sensitivity to sounds in the native lan-
guage they hear every day, while becoming increasingly less sensitive to nonnative
FIGURE 6.4 Speech perception This infant is participating in a study of speech perception in
the laboratory of Janet Werker. The baby has learned to turn his head to the sound source whenever he
hears a change from one sound to another. a correct head turn is rewarded by an exciting visual dis-
play, as well as by the applause and praise of the experimenter. To make sure that neither the mother
nor the experimenter can influence the child’s behavior, they are both wearing headphones that prevent
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FIGURE 6.5 percent of infants able
to discriminate foreign-language speech
sounds Infants’ ability to discriminate
between speech sounds that are not in their
native language declines between 6 and
12 months of age. Most 6-month-olds from
english-speaking families readily discrimi-
nate between syllables in hindi (blue bars)
and Nthlakapmx (green bars), but most 10-
to 12-month-olds do not. (adapted from

228 n chapTer 6 DEVELOPMENT OF LANGUAGE AND SYMBOL USE
speech sounds. Indeed, becoming a native listener is one of the greatest accom-
plishments of the infant’s first year of postnatal life.
Word Segmentation
As infants begin to tune into the speech sounds of their language, they also begin to
discover another crucial feature of the speech surrounding them: words. This is no
easy feat. Unlike the words typed on this page, there are no spaces between words
in speech, even in IDS. What this means is that most utterances infants hear are
strings of words without pauses between them, like “Lookattheprettybaby! Haveyou
everseensuchaprettybabybefore?” They then have to figure out where the words start
and end. Remarkably, they begin the process of word segmentation during the
second half of the first year.
In the first demonstration of infant word segmentation, Jusczyk & Aslin (1995)
used a head-turn procedure designed to assess infants’ auditory preferences. In this
study, 7-month-olds first listened to passages of speech in which a particular word
was repeated from sentence to sentence—for example, “The cup was bright and
shiny. A clown drank from the red cup. His cup was filled with milk.” After listening
to these sentences several times, infants were tested using the head-turn preference
procedure to see whether they recognized the words repeated in the sentences. In
this method, flashing lights mounted near two loudspeakers located on either side
of an infant are used to draw the infant’s attention to one side or the other. As soon
as the infant turns to look at the light, an auditory stimulus is played through the
speaker, and it continues as long as the infant is looking in that direction. The length
of time the infant spends looking at the light—and hence listening to the sound—
provides a measure of the degree to which the infant is attracted to that sound.
Infants in this study were tested on repetitions of words that had been presented
in the sentences (such as cup) or words that had not (such as bike). The researchers
found that infants listened longer to words that they had heard in the passages of
fluent speech, as compared with words that never occurred in the passages. This
result indicates that the infants were able to pull the words out of the stream of
speech—a task so difficult that even sophisticated speech-recognition software
often fails at it.
How do infants find words in pause-free speech? They appear to be remark-
ably good at picking up regularities in their native language that help them to find
word boundaries. One example is stress patterning, an element of prosody. In En-
glish, the first syllable in two-syllable words is much more likely to be stressed than
the second syllable (as in “English,” “often,” and “second”). By 8 months of age,
English-learning infants expect stressed syllables to begin words and can use this
information to pull words out of fluent speech (Curtin, Mintz, & Christiansen,
2005; Johnson & Jusczyk, 2001; Jusczyk, Houston, & Newsome, 1999; Thiessen
& Saffran, 2003).
Another regularity to which infants are surprisingly sensitive concerns the
distributional properties of the speech they hear. In every language, certain sounds
are more likely to appear together than are others. Sensitivity to such regularities
in the speech stream was demonstrated in a series of statistical-learning experi-
ments in which babies learned new words based purely on regularities in how often
a given sound followed another (Aslin, Saffran, & Newport, 1998; Saffran, Aslin,
& Newport, 1996). The infants listened to a 2-minute recording of four different
three-syllable “words” (e.g., tupiro, golabu, bidaku, padoti) repeated in random order
with no pauses between the “words.” Then, on a series of test trials, the babies were
word segmentation n the process of
discovering where words begin and end in
fluent speech
distributional properties n the phe-
nomenon that in any language, certain
sounds are more likely to appear together
than are others

L A N G U A G E D E V E L O P M E N T n 229
presented with the “words” they had heard (e.g., bidaku, padoti) and with sequences
that were not words (such as syllable sequences that spanned a word boundary—
for example, kupado, made up from the end of bidaku and the beginning of padoti).
Using the same kind of preferential listening test described for the Juscyzk &
Aslin (1995) study on the previous page, the researchers found that infants dis-
criminated between the words and the sequences that were not words. To do so,
the babies must have registered that certain syllables often occurred together in the
sample of speech they heard. For example, “bi” was always followed by “da” and “da”
was always followed by “ku,” whereas “ku” could be followed by “tu,” “go,” or “pa.”
Thus, the infants used recurrent sound patterns to fish words out of the passing
stream of speech. This ability to learn from distributional properties extends to real
languages as well; English-learning infants, for example, can track similar statistical
patterns when listening to Italian IDS (Pelucchi, Hay, & Saffran, 2009).
Identifying these regularities in speech sounds supports the learning of words.
After repeatedly hearing novel “words” such as timay and dobu embedded in a long
stream of speech sounds, 17-month-olds readily learned those sounds as labels for
objects (Graf Estes et al., 2007). Similarly, after hearing Italian words like mela and
bici embedded in fluent Italian speech, 17-month-olds who had no prior exposure
to Italian readily mapped those labels to objects (Hay et al., 2011). Having already
learned the sound sequences that made up the words apparently made it easier for
the infants to associate the words with their referents.
Probably the most salient regularity for infants is their own name. Infants as
young as 4½ months will listen longer to repetitions of their own name than to
repetitions of a different but similar name (Mandel, Jusczyk, & Pisoni, 1995). Just
a few weeks later, they can pick their own name out of background conversations
(Newman, 2005). This ability helps them to find new words in the speech stream.
After hearing “It’s Jerry’s cup!” a number of times, 6-month-old Jerry is more likely
to learn the word cup than if he had not heard it right after his name (Bortfeld et
al., 2005). Over time, infants recognize more and more familiar words, making it
easier to pluck new ones out of the speech that they hear.
Infants are exceptional in their ability to identify patterns in the speech sur-
rounding them. They start out with the ability to make crucial distinctions among
speech sounds but then narrow their focus to the sounds and sound patterns that
make a difference in their native language. This process lays the groundwork for
their becoming not just native listeners but also native speakers.
Preparation for Production
In their first months, babies are getting ready to talk. The repertoire of sounds
they can produce is initially extremely limited. They cry, sneeze, sigh, burp, and
smack their lips, but their vocal tract is not sufficiently developed to allow them to
produce anything like real speech sounds. Then, at around 6 to 8 weeks of age, in-
fants begin to coo—producing long, drawn-out vowel sounds, such as “ooohh” or
“aaahh.” Young infants entertain themselves with vocal gymnastics, switching from
low grunts to high-pitched cries, from soft murmurs to loud shouts. They click,
smack, blow raspberries, squeal, all with apparent fascination and delight. Through
this practice, infants gain motor control over their vocalizations.
While their sound repertoire is expanding, infants become increasingly aware
that their vocalizations elicit responses from others, and they begin to engage in
dialogues of reciprocal ooohing and aaahing, cooing and gooing with their parents.
With improvement in their motor control of vocalization, they imitate the sounds
bidakupadotigolabubidakugolabupadotib
idakupadotigolabupadotibidakupadoti…
how quickly could you pick out a word from
a stream of speech like the one shown here?
It takes 8-month-old infants only 2 minutes
of listening.

230 n chapTer 6 DEVELOPMENT OF LANGUAGE AND SYMBOL USE
of their “conversational” partners, even producing higher-pitched sounds when in-
teracting with their mothers and lower-pitched sounds when interacting with their
fathers (de Boysson-Bardies, 1996/1999).
Babbling Sometime between 6 and 10 months of age, but on average at around 7
months, a major milestone occurs: babies begin to babble. Standard babbling involves
producing syllables made up of a consonant followed by a vowel (“pa,” “ba,” “ma”) that
are repeated in strings (“papapa”). Contrary to the long-held belief that infants babble
a wide range of sounds from their own and other languages ( Jakobson, 1941/1968),
research has revealed that babies actually babble a fairly limited set of sounds, some of
which are not part of their native language (de Boysson-Bardies, 1996/1999).
Native language exposure is a key component in the development of babbling.
Although congenitally deaf infants produce vocalizations similar to those of hear-
ing babies until around 5 or 6 months of age, their vocal babbling occurs very late
and is quite limited (Oller & Eilers, 1988). However, some congenitally deaf ba-
bies do “babble” right on schedule—those who are regularly exposed to sign lan-
guage. Infants exposed to ASL babble manually. They produce repetitive hand
movements that are components of full ASL signs, just as vocally babbled sounds
are repeated components of spoken words (Petitto & Marentette, 1991). Thus, like
infants learning a spoken language, infants learning signed languages seem to ex-
periment with the elements that are combined to make meaningful words in their
native language (Figure 6.6).
As their babbling becomes more varied, it gradually takes on the sounds, rhythm,
and intonational patterns of the language infants hear daily. In a simple but clever
experiment, French adults listened to the babbling of a French 8-month-old and an
8-month-old from either an Arabic- or Cantonese-speaking family. When asked to
identify which baby was the French one in each pair, the adults chose correctly 70%
of the time (de Boysson-Bardies, Sagart, & Durand, 1984). Thus, before infants
utter their first meaningful words, they are, in a sense, native speakers of a language.
early interactions Before we turn to the next big step in language production—
uttering recognizable words—it is important to consider the social context that
promotes language development in most societies. Even before infants start speak-
ing, they display the beginnings of communicative competence: the ability to com-
municate intentionally with another person.
The first indication of communicative competence is turn-taking. In a conversa-
tion, mature participants alternate between speaking and listening. Jerome Bruner
and his colleagues (Bruner, 1977; Ratner & Bruner, 1978) have proposed that learn-
ing to take turns in social interactions is facilitated by parent–infant games, such as
peekaboo and “give and take,” in which caregiver and baby take turns giving and
receiving objects. In these “dialogues,” the infant has the opportunity to alternate
between an active and a passive role, as in a conversation in which one alternates
between speaking and listening. These early interactions give infants practice in bi-
directional communication, providing infants with a scaffold to learn how to use
language to converse with others. Indeed, recent research suggests that caregivers’
babbling n repetitive consonant–vowel
sequences (“bababa . . .”) or hand move-
ments (for learners of signed languages)
produced during the early phases of lan-
guage development
FIGURE 6.6 Manual babbling Babies who are exposed to the sign
language of their deaf parents babble with their hands. a subset of
their hand movements differs from those of infants exposed to spoken
language, and corresponds to the rhythmic patterning of adult signs.
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L A N G U A G E D E V E L O P M E N T n 231
responses to infant babbling may serve a similar function.
When an adult labels an object for an infant just after the in-
fant babbles, the infant’s learning of the label is more greatly
enhanced than when the labeling occurs in the absence of
babbling (Goldstein et al., 2010). The results of this study
suggest that babbling may serve as a signal to the caregiver
that the infant is attentive and ready to learn. This early
back-and-forth may also provide infants with practice in
conversational turn-taking.
As discussed in Chapter 4, successful communication also
requires intersubjectivity, in which two interacting partners
share a mutual understanding. The foundation of intersub-
jectivity is joint attention, which, early on, is established by
the parent’s following the baby’s lead, looking at and com-
menting on whatever the infant is looking at. By 12 months
of age, infants have begun to understand the communicative
nature of pointing, with many also being capable of mean-
ingful pointing themselves (Behne et al., 2012).
We have thus seen that infants spend a good deal of time
getting ready to talk. Through babbling, they gain some initial level of control over
the production of sounds that are necessary to produce recognizable words. As
they do so, they already begin to sound like their parents. Through early interac-
tions with their parents, they develop interactive routines similar to those required
in the use of language for communication. We will now turn our attention to the
processes that lead to infants’ first real linguistic productions: words.
First Words
When babies first begin to segment words from fluent speech, they are
simply recognizing familiar patterns of sounds without attaching any
meaning to them. But then, in a major revolution, they begin to recognize
that words have meaning.
The problem of reference The first step for infants in acquiring the
meanings of words is to address the problem of reference, that is, to start
associating words and meaning. Figuring out which of the multitude of
possible referents is the right one for a particular word is, as the philoso-
pher Willard Quine (1960) pointed out, a very complex problem. If a child
hears someone say “bunny” in the presence of a rabbit, how does the child
know whether this new word refers to the rabbit itself, to its fuzzy tail, to
the whiskers on the right side of its nose, or to the twitching of its nose?
That the problem of reference is a real problem is illustrated by the case
of a toddler who thought “Phew!” was a greeting, because it was the first
thing her mother said on entering the child’s room every morning (Ferrier, 1978).
Early Word Recognition
Infants begin associating highly familiar words with their highly familiar referents
surprisingly early on. When 6-month-olds hear either “Mommy” or “Daddy,” they
look toward the appropriate person (Tincoff & Jusczyk, 1999). Infants gradually
come to understand the meaning of less frequently heard words, with the pace of
their vocabulary-building varying greatly from one child to another. Remarkably,
This toddler is pointing to get her father to
share her attention—to achieve intersubjec-
tivity. Once the father identifies the focus of
his daughter’s attention, he may even decide
to add it to the shopping basket.
O
C
E
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N
/
C
O
R
B
IS
a classic problem posed by philosopher
Willard Quine was how someone who does
not know the word rabbit could figure out
exactly what it refers to. This mother may be
helping her son learn a new word by labeling
the referent while it is the focus of her son’s
attention.
D
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/
D
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S
reference n in language and speech, the
associating of words and meaning

232 n chapTer 6 DEVELOPMENT OF LANGUAGE AND SYMBOL USE
parents are often unaware of just how many words their infants rec-
ognize. Using a computer monitor, Bergelson and Swingley (2012)
showed infants pairs of pictures of common foods and body parts
and tracked the infants’ eye gaze when one of the pictures was
named. They found that even 6-month-olds looked to the correct
picture significantly more often than would be expected by chance,
demonstrating that they recognized the names of these items. Strik-
ingly, most of their parents reported that the infants did not know
the meanings of these words. So not only do infants understand far
more words than they can produce; they also understand far more
words than even their caregivers realize.
One of the remarkable features of infants’ early word recognition
is how rapidly they understand what they are hearing. To illumi-
nate the age-related dynamics of this understanding, Fernald and
her colleagues presented infants with images depicting pairs of fa-
miliar objects, such as a dog and a baby, and observed how quickly the infants moved
their eyes to the correct object after hearing its label used (e.g., “Where’s the baby?”).
The researchers found that whereas 15-month-olds waited until they had heard the
whole word to look at the target object, 24-month-olds looked at the correct ob-
ject after hearing only the first part of its label, just as adults do (Fernald et al., 1998;
Fernald, Perfors, & Marchman, 2006; Fernald, Swingley, & Pinto, 2001). Older in-
fants can also use context to help them recognize words. For example, those who are
learning a language that has a grammatical gender system (like Spanish or French)
can use the gender of the article preceding the noun (la versus el in Spanish; la versus
le in French) to speed their recognition of the noun itself (Lew-Williams & Fernald,
2007; Van Heugten & Shi, 2009). Other visual-fixation research has shown that older
infants can even recognize familiar words when they are mispronounced (e.g., “vaby”
for “baby,” “gall” for “ball,” “tog” for “dog,” etc.), though their recognition is slower
than when they hear the words pronounced correctly (Swingley & Aslin, 2000).
early word production Gradually, infants begin to say some of the words they un-
derstand, with most producing their first words between 10 and 15 months of age.
The words a child is able to say are referred to as the child’s productive vocabulary.
What counts as an infant’s “first word”? It can be any specific utterance con-
sistently used to refer to something or to express something. Even with this loose
criterion, identification of an infant’s earliest few words can be problematic. For
one thing, doting parents often misconstrue their child’s babbling as words. For
another, early words may differ from their corresponding adult forms. For exam-
ple, Woof was one of the first words spoken by the boy whose linguistic progress
was illustrated at the beginning of this chapter. It was used to refer to the dog next
door—both to excitedly name the animal when it appeared in the neighbors’ yard
and to wistfully request the dog’s presence when it was absent.
Infants’ early word productions are limited by their ability to pronounce words
clearly enough that an adult can recognize them. To make life easier for themselves,
infants adopt a variety of simplification strategies (Gerken, 1994). For example,
they leave out the difficult bits of words, turning banana into “nana,” or they sub-
stitute easier sounds for hard-to-say ones—“bubba” for brother, “wabbit” for rab-
bit. Sometimes they reorder parts of words to put an easier sound at the beginning
of the word, as in the common “pasketti” (for spaghetti) or the more idiosyncratic
“Cagoshin” (the way the child quoted at the beginning of the chapter continued for
several years to say Chicago).
When this infant hears the word mouth,
will she look at the picture of the mouth or
at the picture of the apple? The speed and
accuracy of her looks in response to words
provide a useful measure of her vocabulary
knowledge.
E
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A
B
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LS
O
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L A N G U A G E D E V E L O P M E N T n 233
Once children start talking, what do they talk about? The early productive vo-
cabularies of children in the United States include names for people, objects, and
events from the child’s everyday life (Clark, 1979; K. Nelson, 1973). Children
name their parents, siblings, pets, and themselves, as well as other personally im-
portant objects such as cookies, juice, and balls. Frequent events and routines are
also labeled—“up,” “bye-bye,” “night-night.” Important modifiers are also used—
“mine,” “hot,” “all gone.” Table 6.1 reveals substantial cross-linguistic similarities
in the content of the first 10 words of children in the United States, Hong Kong,
and Beijing. As the table shows, many of infants’ first words in the three societies
referred to specific people or were sound effects (Tardif et al., 2008).
In the early productive vocabularies of children learning English, nouns predomi-
nate. One reason may be that because nouns label entities—whereas verbs represent
relations among entities—the meanings of nouns are easier to pick up from observa-
tion than are the meanings of verbs (Gentner, 1982). Similarly, words that are easier
to picture—that are more imageable—are easier for infants and toddlers to learn
(McDonough et al., 2011). Another reason is that middle-class American mothers
(the group most frequently studied) engage in frequent bouts of object-labeling for
their infants—“Look, there’s a turtle! Do you see the turtle?” (Fernald & Morikawa,
1993)—and the proportion of nouns in very young children’s vocabularies is related
to the proportion of nouns in their mother’s speech to them (Pine, 1994). Signifi-
cantly, the pattern of object-labeling by mothers differs across cultures and contexts.
LY
N
N
J
O
H
N
S
T
O
N
P
R
O
D
U
C
T
IO
N
S
,
IN
C
.
/
D
IS
T
R
IB
U
T
E
D
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IT
E
D
F
E
AT
U
R
E
S
Y
N
D
IC
AT
E
,
IN
C
.

234 n chapTer 6 DEVELOPMENT OF LANGUAGE AND SYMBOL USE
TABLE 6.1
rank-Ordered List of earliest Words in Three Languages*
English Putonghua (Mandarin) Cantonese
Daddy Daddy Mommy
Mommy Aah Daddy
BaaBaa Mommy Grandma (paternal)
Bye YumYum Grandpa (paternal)
Hi Sister (older) Hello?/Wei?
UhOh UhOh (Aiyou) Hit
Grr Hit Uncle (paternal)
Bottle Hello/Wei Grab/grasp
YumYum Milk Auntie (maternal)
Dog Naughty Bye
No Brother (older) UhOh (Aiyou)
WoofWoof Grandma (maternal) Ya/Wow
*Words in boldface were common across all three languages; those in italics were common for two of the languages.
Source: Tardif et al., 2008.
TABLE 6.2
examples of Young children’s Overextensions of Word Meaning
Word Referents
ball ball, balloon, marble, apple, egg, spherical water tank (Rescorla, 1980)
cat cat, cat’s usual location on top of TV when absent (Rescorla, 1980)
moon moon, half-moon-shaped lemon slice, circular chrome dial on dishwasher, half a Cheerio,
hangnail (Bowerman, 1978)
snow snow, white flannel bed pad, white puddle of milk on floor (Bowerman, 1978)
baby own reflection in mirror, framed photograph of self, framed photographs of others (Hoff, 2001)
holophrastic period n the period when
children begin using the words in their
small productive vocabulary one word at
a time
overextension n the use of a given word
in a broader context than is appropriate
For example, Japanese mothers label objects far less often than do American moth-
ers (Fernald & Morikawa, 1993). In the context of toy play, Korean mothers use
more verbs than nouns, a pattern very different from that observed in English-
speaking mothers (Choi, 2000). And indeed, infants in Korea learn nouns and verbs
at the same rate, unlike English-learning infants (Choi & Gopnik, 1995).
Initially, infants say the words in their small productive vocabulary only one
word at a time. This phase is referred to as the holophrastic period, because the
child typically expresses a “whole phrase”—a whole idea—with a single word. For
example, a child might say “Drink!” to express the desire for a glass of juice. Chil-
dren who produce only one-word utterances are not limited to single ideas; they
manage to express themselves by stringing together successive one-word utter-
ances. An example is a little girl with an eye infection who pointed to her eye, say-
ing “Ow,” and then after a pause, “Eye” (Hoff, 2001).
What young children want to talk about quickly outstrips the number
of words in their limited vocabularies, so they make the words they do know
perform double duty. One way they do this is through overextension—using
a word in a broader context than is appropriate, as when children use dog for
any four-legged animal, daddy for any man, moon for a dishwasher dial, or hot
for any reflective metal (Table 6.2). Most overextensions represent an effort to

L A N G U A G E D E V E L O P M E N T n 235
communicate rather than a lack of knowledge, as demonstrated by research in
which children who overextended some words were given comprehension tests
(Naigles & Gelman, 1995). In one study, children were shown pairs of pictures
of entities for which they generally used the same label—for instance, a dog and
a sheep, both of which they normally referred to as “dog.” However, when asked
to point to the sheep, they chose the correct animal. Thus, these children under-
stood the meaning of the word sheep, but because it was not in their productive
vocabulary, they used a related word that they knew how to say in order to talk
about the animal.
13 million for an average child with parents
on welfare.
How do these differences affect chil-
dren’s language development? Not sur-
prisingly, children from higher-SES groups
have larger vocabularies than those of chil-
dren from lower-SES groups (Fenson et al.,
1994; Huttenlocher et al., 1991). Indeed,
a study of high-SES and mid-SES mothers
and their 2-year-old children found that SES
differences in maternal speech (e.g., num-
ber and length of utterances, richness of
vocabulary, and sentence complexity) pre-
dicted some of the differences in children’s
spoken vocabularies (Hoff, 2003). For in-
stance, higher-SES mothers tended to use
longer utterances with their children than
did mid-SES parents, giving their children
access not only to more words but also to
more complex grammatical structures (Hoff,
2003). Such differences in maternal speech
even affect how quickly toddlers recognize
familiar words: children whose mothers pro-
vided more maternal speech at 18 months
were faster at recognizing words at 24
months than were children whose mothers
provided less input (Hurtado, Marchman, &
Fernald, 2008).
Similar findings emerge in the school con-
text. For example, when preschool children
with low language skills are placed in class-
rooms with peers who also have low language
skills, they show less language growth than
do their counterparts who are placed with
classmates who have high language skills
(Justice et al., 2011). These peer effects
have important implications for programs
like Head Start (discussed fully in Chapter
8), which are designed to enhance language
development and early literacy for children
living in poverty. Unfortunately, congregating
children from lower-SES families together
in the same preschool classrooms may limit
their ability to “catch up.” However, there
is the possibility that negative peer effects
may be offset by positive teacher effects.
For example, one study found that children
whose preschool teachers used a rich vocab-
ulary showed better reading comprehension
in 4th grade than did children whose pre-
school teachers used a more limited vocabu-
lary (Dickinson & Porche, 2011).
These results suggest that for a variety of
reasons, parents’ SES affects the way they
talk to their children; in turn, those individ-
ual differences have a substantial influence
on the way their children talk. These differ-
ences can be intensified by the linguistic
abilities of children’s peers and teachers.
For children in low-SES environments, the
potential negative effects of these influences
may be offset by interventions ranging from
increased access to children’s books (which
provide enriched linguistic environments) to
enhancing teacher training in low-income
preschool settings (Dickinson, 2011). Re-
gardless of the source, what goes in is what
comes out: we can only learn words and
grammatical structures that we hear (or see
or read) in the language surrounding us.
BOX 6.2: individual differences
THE ROLE OF FAMILY AND SCHOOL CONTEXT
IN EARLY LANGUAGE DEVELOPMENT
Within a family, parents often notice sig-
nificant linguistic differences between their
children. Within a given community, such
differences can be greatly magnified. In a
single kindergarten classroom, for example,
there may be a tenfold difference in the
number of words used by different children.
What accounts for these differences?
The number of words children know is
intimately related to the number of words
that they hear, which, in turn, is linked to
their caregivers’ vocabularies. One of the
key determinants of the language chil-
dren hear is the socioeconomic status of
their parents. In a seminal study, Hart and
Risley (1994) recorded the speech that 42
parents used with their children over the
course of 2½ years, from before the infants
were talking until they were 3 years of age.
Some of the parents were upper-middle
class, others were working class, and oth-
ers were on welfare. The results were aston-
ishing: the received linguistic experience of
the average child whose parents were on
welfare (616 words per hour) was half that
of the average working-class parents’ child
(1251 words per hour) and less than one-
third that of the average child in a profes-
sional family (2153 words per hour). The
researchers did the math and suggested
that after 4 years, an average child with
upper- middle-class parents would have ac-
cumulated experience with almost 45 mil-
lion words, compared with 26 million for an
average child in a working-class family and

236 n chapTer 6 DEVELOPMENT OF LANGUAGE AND SYMBOL USE
Word learning After the appearance of their first words, children
typically plod ahead slowly, reaching a productive vocabulary of 50
or so words by around 18 months of age. At this point, the rate of
learning appears to accelerate, leading to what appears to be a “vo-
cabulary spurt” (e.g., L. Bloom, 1973; McMurray, 2007). Although
scholars disagree about whether learning actually speeds up for all or
even most children (Bloom, 2000), it is clear that children’s commu-
nicative abilities are growing rapidly (Figure 6.7).
What accounts for the skill with which young children learn
words? When we look closely, we see that there are multiple sources
of support for learning new words, some coming from the people
around them, and some generated by the children themselves.
ADULT INFLUENCES ON WORD LEARNING In addition to using IDS, which
makes word learning easier for infants, adults facilitate word learn-
ing by highlighting new words. For example, they stress new words,
or place them at the end of a sentence. They also tend to label objects that are al-
ready the focus of the child’s attention, thereby reducing uncertainty about the ref-
erent (Masur, 1982; Tomasello, 1987; Tomasello & Farrar, 1986). Their repetition
of words also helps; young children are more likely to acquire words their parents
use frequently (Huttenlocher et al., 1991). Another stimulus to word learning that
adults provide involves naming games, in which they ask the child to point to a
series of named items—“Where’s your nose?” “Where’s your ear?” “Where’s your
tummy?” There is also some evidence that parents may facilitate their children’s
word learning by maintaining spatial consistency with the objects they are label-
ing. For instance, in a study in which parents labeled novel objects for their infants,
the infants learned the names of the objects more readily when the objects were in
the same location each time they were labeled (Samuelson et al., 2011). Presum-
ably, consistency in the visual environment helps children map words onto objects
and events in that environment. In Box 6.3, we discuss recent research focused on
a currently popular means by which some parents try to “outsource” word
learning: technology.
CHILDREN’S CONTRIBUTIONS TO WORD LEARNING When confronted with words
they haven’t heard before, children actively exploit the context in which the
new word was used in order to infer its meaning. A classic study by Carey
and Bartlett (1978) demonstrated fast mapping—the process of rapidly
learning a new word simply from hearing the contrastive use of a familiar
word and the unfamiliar word. In the course of everyday activities in a pre-
school classroom, an experimenter drew a child’s attention to two trays—one
red, the other an uncommon color the child would not know by name—and
asked the child to get “the chromium tray, not the red one.” The child was
thus provided with a contrast between a familiar term (red) and an unfamiliar
one (chromium). From this simple contrast, the participants inferred which
tray they were supposed to get and that the name of the color of that tray
was “chromium.” After this single exposure to a novel word, about half the
children showed some knowledge of it 1 week later by correctly picking out
“chromium” from an array of paint chips.
Some theorists have proposed that the many inferences children make in
the process of learning words are guided by a number of assumptions (some-
times referred to as principles, constraints, or biases) that limit the possible
Sentences Vocabulary spurt First words
Language achievement
A
ge
(
in
m
on
th
s)

12
15
18
21
24
27
30
33
9
FIGURE 6.7 Language achievement
On average, american children say their
first word at around 13 months, experience
a vocabulary spurt at around 19 months,
and begin to produce simple sentences at
around 24 months. however, the bars above
and below these means show a substan-
tial amount of variability in when different
children achieve each of these milestones.
This young Inuit child is playing a naming
game; her mother has just asked her to
point to her nose.
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L A N G U A G E D E V E L O P M E N T n 237
meanings children entertain for a new word. For example, children expect that a
given entity will have only one name, an expectancy referred to as the mutual ex-
clusivity assumption by Woodward and Markman (1998). Early evidence for this
assumption came from a study in which 3-year-olds saw pairs of objects—a famil-
iar object for which the children had a name and an unfamiliar one for which they
had no name. When the experimenter said, “Show me the blicket,” the children
mapped the novel label to the novel object, the one for which they had no name
(Markman & Wachtel, 1988). Even 16-month-old infants do the same (Graham,
Poulin-Dubois, & Baker, 1998). (See Figure 6.8a.) Interestingly, bilingual and tri-
lingual infants, who are accustomed to hearing more than one name for a given
object, are less likely to follow the mutual exclusivity principle (Byers-Heinlein &
Werker, 2009).
Markman and Woodward (Markman, 1989; Woodward & Markman, 1998)
also proposed the whole-object assumption, according to which children expect a
novel word to refer to a whole object rather than to a part, property, action, or other
aspect of the object. Thus, in the case of Quine’s rabbit problem (see page 231),
the whole-object assumption leads children to map the label “bunny” to the whole
animal, not just to its tail or the twitching of its nose.
When confronted with novel words, children also exploit a variety of pragmatic
cues to their meaning by paying attention to the social contexts in which the words
are used. For example, children use an adult’s focus of attention as a cue to word
meaning. In a study by Baldwin (1993), an experimenter showed 18-month-olds
two novel objects and then concealed them in separate containers. Next, the ex-
perimenter peeked into one of the containers and commented, “There’s a modi in
here.” The adult then removed and gave both objects to the child. When asked for
the “modi,” the children picked the object that the experimenter had been look-
ing at when saying the label. Thus, the infants used the relation between eye gaze
and labeling to learn a novel name for an object before they had ever seen it (see
Figure 6.8b).
Another pragmatic cue that children use to draw inferences about a word’s
meaning is intentionality (Tomasello, 2007). For instance, in one study, 2-year-
olds heard an experimenter announce, “Let’s dax Mickey Mouse.” The experi-
menter then performed two actions on a Mickey Mouse doll, one carried out in
a coordinated and apparently intentional way, followed by a pleased comment
(“There!”), and the other carried out in a clumsy and apparently accidental way,
followed by an exclamation of surprise (“Oops!”). The children interpreted the
novel verb dax as referring to the action the adult apparently intended to perform
(Tomasello & Barton, 1994). Infants can even use an adult’s emotional response
to infer the name of a novel object that they cannot see (Tomasello, Strosberg,
& Akhtar, 1996). In a study establishing this fact, an adult announced her in-
tention to “find the gazzer.” She then picked up one of two objects and showed
obvious disappointment with it. When she gleefully seized the second object,
the infants inferred that it was a “gazzer.” (Figure 6.8c depicts another instance
in which a child infers the name of an unseen object from an adult’s emotional
expression.)
The degree to which preschool children take a speaker’s intention into account
is shown by the fact that if an adult’s labeling of an object conflicts with their
knowledge of that object, they will nevertheless accept the label if the adult clearly
used it intentionally ( Jaswal, 2004). When an experimenter simply used the label
“dog” in referring to a picture of a catlike animal, preschool children were reluc-
tant to extend the label to other catlike stimuli. However, they were much more
fast mapping n the process of rapidly
learning a new word simply from hearing
the contrastive use of a familiar and the
unfamiliar word
pragmatic cues n aspects of the social
context used for word learning

238 n chapTer 6 DEVELOPMENT OF LANGUAGE AND SYMBOL USE
willing to do so when the experimenter made it clear that he really intended his
use of the unexpected label by saying, “You’re not going to believe this, but this is
actually a dog.” Similarly, if a child has heard an adult refer to a cat as “dog,” the
child will be reluctant to subsequently learn a new word used by that “untrust-
worthy” adult (e.g., Koenig & Harris, 2005; Koenig & Woodward, 2010; Sabbagh
& Shafman, 2009).
Another way young children can infer the meaning of novel words is by tak-
ing cues from the linguistic context in which the words are used. In one of the first
FIGURE 6.8 cues for word learning (a) Mutual exclusivity: Because
this child already knows the name of the familiar object on the table, she
will pick up the novel object when the adult asks her to “show me the
(c) pragmatic cues: This child will learn “gazzer” as the name of the novel object that the adult smiles
at triumphantly after she had previously announced that she wanted to find “the gazzer.”
(b) pragmatic cues: This child will assume that the novel word she hears
the experimenter saying applies to the novel object the experimenter is
looking at, even though the child cannot see the object and is looking at a
different novel object when she actually hears the word.
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L A N G U A G E D E V E L O P M E N T n 239
experiments on language acquisition, Brown (1957) established that
the grammatical form of a novel word influences children’s interpreta-
tion of it. He showed preschool children a picture of a pair of hands
kneading a mass of material in a container (Figure 6.9). The picture was
described to one group of children as “sibbing,” to another as “a sib,”
and to a third as “some sib.” The children subsequently interpreted sib
as referring to the action, the container, or the material, depending on
which grammatical form (verb, count noun, or mass noun) of the word
they had heard.
Two- and 3-year-old children also use the grammatical category of
novel words to help interpret their meaning (e.g., Hall, 1994; Hall,
Waxman, & Hurwitz, 1993; Markman & Hutchinson, 1984; Waxman,
1990). Hearing “This is a dax,” they assume that dax refers to an object,
as well as to other objects from the same category. In contrast, “This is
a dax one” suggests that dax refers to a property of the object (e.g., its
color or texture), while “This is dax” suggests that dax is a proper noun
(a name). Even infants and toddlers can draw on some of these links to
interpret the meaning of novel words (e.g., Booth & Waxman, 2009; Waxman &
Hall, 1993; Waxman & Markow, 1995, 1998).
Children’s interpretation of novel words applied to objects is particularly guided
by the objects’ shape, possibly because shape is a good cue to category member-
ship. Children readily extend a novel noun to novel objects of the same shape,
even when those objects differ dramatically in size, color, and texture (Graham
& Poulin-Dubois, 1999; Landau, Smith, & Jones, 1988; L. B. Smith, Jones, &
Landau, 1992). Thus, a child who hears a U-shaped
wooden block called “a dax” will assume that dax also
refers to a U-shaped object covered in blue fur or to a
U-shaped piece of red wire—but not to a wooden block
of a different shape (Figure 6.10). A shape bias is also
evident in young children’s spontaneous extension of fa-
miliar words to novel objects that are vaguely similar to
familiar entities (e.g., a cone might be referred to as a
“mountain”) (Samuelson & Smith, 2005).
Another potentially useful cue to word meaning is the
repeated correspondence between words the child hears
and objects the child observes in the world. Any single
scene is ambiguous. For example, if the child sees four
different novel objects together and hears the label “dax,”
the child has no way of knowing which object is the dax
(this ambiguity is similar to that in Quine’s “bunny” ex-
ample described earlier). But across experiences, the
child might observe that whenever “dax” is said, one of
those four objects is always present, and thus that object
is probably the dax. Through this process of cross- situational word learning, even
infants can narrow down the possible meanings of new words (e.g., L. Smith & Yu,
2008; Vouloumanos & Werker, 2009).
Children also use the grammatical structure of whole sentences to figure out
meaning—a strategy referred to as syntactic bootstrapping (Fisher, 1999; Fisher,
Gleitman, & Gleitman, 1991; Gertner, Fisher, & Eisengart, 2006; Yuan & Fisher,
2009). An early demonstration of this phenomenon involved showing 2-year-olds
FIGURE 6.9 Linguistic context When
roger Brown, a pioneer in the study of lan-
guage development, described a drawing
like this as “sibbing,” “a sib,” or “some
sib,” preschool children made different
.82
.76
.50
Exemplar
Shape
change
Texture
change
Size
change
FIGURE 6.10 Shape bias In one of
many studies of the shape bias, children
were shown the exemplar at the top of this
figure and told that it was a “dax” (or some
other nonsense word). Then they were asked
which of the objects below the exemplar was
also a “dax.” The numbers under the objects
indicate the proportion of children who
thought each object was a “dax.” as you can
see, they most often thought that the word
referred to the object that was of the same
shape as the exemplar, even if the surface
texture or size was different. (adapted from
Landau, Smith, & Jones, 1988)
syntactic bootstrapping n the strategy
of using the grammatical structure of
whole sentences to figure out meaning

240 n chapTer 6 DEVELOPMENT OF LANGUAGE AND SYMBOL USE
a videotape of a duck using its left hand to push a rabbit down into a squatting po-
sition while both animals waved their right arms in circles (Figure 6.11) (Naigles,
1990). As they watched, some children
were told “The duck is kradding the rab-
bit”; others were told “The rabbit and the
duck are kradding.” All the children then
saw two videos side by side, one show-
ing the duck pushing on the rabbit and
the other showing both animals waving
their arms in the air. Instructed to “Find
kradding,” the two groups looked at the
event that matched the syntax they had
heard while watching the initial video.
Those who had heard the first sentence
took “kradding” to mean what the duck
When adults enter a new language culture,
they often have access to many technologi-
cal aids—from pocket dictionaries to smart-
phone apps for translations—to help them
get around and ask for what they need. They
can also harness technology to learn a new
language, from collegiate digital language
labs to commercial training programs like
Rosetta Stone.
What about infants? They, too, are often
immersed in technology. Indeed, over the
past two decades, there was a “brainy-
baby” craze in which businesses earned
hundreds of millions of dollars marketing
all manner of electronic games, toys, and
DVDs that claimed to enhance babies’ intel-
lectual growth. Some of these claims were
laughable. For example, one of your authors
purchased a teething ring for her baby and
was astonished to read on the packaging
that the ring supposedly improves an in-
fant’s language development by enhancing
early oral-motor skills. Other claims seemed
more plausible but were subsequently called
into serious question by developmental re-
search—so much so that the companies
producing these products (e.g., “Baby Ein-
stein”) were forced to stop promoting their
“educational” value.
However, there is still concern over tech-
nology marketed for children younger than
2 years because it reduces the time infants
and toddlers spend actively engaged with
caregivers and objects, their best source for
learning. In a large-scale study that included
more than 1000 children younger than 2
years, researchers examined the associa-
tion between TV/DVD viewing and vocabu-
lary development (Zimmerman, Cristakis,
& Meltzoff, 2007). Crucially, the authors
controlled for family demographics (in-
cluding parents’ education, family income,
race/ ethnicity, and so forth) that may influ-
ence media use. For 8- to 16-month-olds,
there was a negative correlation between
the amount of time infants watched DVDs
and parental reports of the infants’ vocab-
ularies: the more the babies watched, the
lower their vocabulary scores. Note that this
negative relationship was observed only for
DVDs marketed as “educational” for ba-
bies; other types of programming (including
both educational and noneducational chil-
dren’s television programs) showed no as-
sociation with vocabulary development. For
the older infants in the study (between 17
and 24 months of age), the negative relation-
ship disappeared. Contrary to many parents’
beliefs, the amount of time parents spent
watching TV with their children did not af-
fect the children’s vocabulary scores. These
results are consistent with the American
Academy of Pediatrics’ recommendation to
minimize screen time for children younger
than 2 years.
BOX 6.3: applications
iBABIES: TECHNOLOGY AND LANGUAGE LEARNING
as shown in this figure from DeLoache et al.
(2010), the infants who learned from parents
(shown in the first column) performed best on
the study’s measure of word learning. Infants
in the two video-learning conditions (middle
two columns) did no better than the control
group (last column).
Condition
P
er
ce
n
ta
ge
c
or
re
ct
0
10
20
30
40
50
60
Parent
teaching
Video with
interaction
Video with
no interaction
Control
FIGURE 6.11 Syntactic bootstrapping
When children in Naigles’s (1990) study
heard an adult describe this filmed scene as
“The duck is kradding the rabbit,” they used
the syntactic structure of the sentence to
infer that kradding is what the duck is doing
LE
T
IT
IA
R
.
N
A
IG
LE
S
,
U
N
IV
E
R
S
IT
Y
O
F
C
O
N
N
E
C
T
IC
U
T

L A N G U A G E D E V E L O P M E N T n 241
had been doing to the rabbit, whereas those who had heard the second sentence
thought it meant what both animals had been doing. Thus, the children had ar-
rived at different interpretations for a novel verb based on the structure of the sen-
tence in which it was embedded.
As you can see, infants and young children have a remarkable ability to learn
new words as object names. Under some circumstances, they are also able to learn
nonlinguistic “labels” for objects. Infants between 13 and 18 months of age map an
experimenter’s gestures or nonverbal sounds (e.g., squeaks and whistles) onto novel
objects just as readily as they map words (Namy, 2001; Namy & Waxman, 1998;
Woodward & Hoyne, 1999). By 20 to 26 months of age, however, they accept only
words as names. And when novel labels are presented via computer rather than
through interaction with an adult, even 12-month-olds accept only words as labels,
not other nonverbal sounds (MacKenzie, Graham, & Curtin, 2011). Thus, infants
learn quite early on that strings of phonemes are more likely to carry meaning than
other types of sounds.
In the most rigorous study to date, De-
Loache and colleagues (2010) used random
assignment and an objective test of vocab-
ulary to determine whether a best-selling
“educational” DVD had an impact on lan-
guage development. The DVD in question
was marketed to infants at least 12 months
old. The researchers randomly assigned 12-
to 18-month-olds into four groups. Infants
in the video-with-interaction group watched
the video with a parent 5 times a week over
4 weeks; the parent was asked to interact
naturally with the infant while watching. In-
fants in the video-without-interaction group
received the same amount of exposure, but
without a parent watching along with them.
This mimics a common situation at home,
where parents might be in the same room
but are engaged in another activity. Infants
in the parent-teaching group did not watch
the video at all. Instead, their parents were
given a list of 25 words featured on the
video and asked to teach the infants those
words in whatever way felt most natural to
them. Finally, infants in the control group
received no intervention, serving as a base-
line for typical vocabulary development.
At the beginning and end of the study,
the infants were tested on a subset of the
words featured on the DVD. Infants in the
DVD-viewing conditions showed no more
advancement in vocabulary than
the infants in the control group
did. The infants who showed
the greatest vocabulary devel-
opment were the infants in the
parent-teaching group. Interest-
ingly, the performance of infants
in the DVD-viewing conditions
was unrelated to how much par-
ents thought their infant had
learned from the DVD. However,
there was a correlation between
how much the parents liked the
DVD themselves and how much
they thought their infant had
learned: the more parents liked
the DVD, the more likely they were to over-
estimate its positive effects.
Although this area of research is still rela-
tively new, the results thus far suggest that
outsourcing infants’ vocabulary develop-
ment to their passive observation of edu-
cational media does not match up with how
infants actually learn. Even the best tech-
nology cannot substitute for a caregiver who
is interacting with the child. The impor-
tance of such interaction was highlighted
by a study in which toddlers learned new
words from an adult in one of three different
conditions: (1) in-person interaction with
the adult; (2) interaction with the adult via
video link; and (3) observation of a video
of the adult interacting with another adult.
The word-learning outcomes for the first two
conditions were the same—and superior to
those in which toddlers were passive ob-
servers (O’Doherty et al., 2011). Questions
about electronic media for infants are only
going to increase, given the delight with
which young children, and even infants,
have embraced the apps on their parents’
smartphones and iPads. As with any type
of activity, a little here and there probably
doesn’t hurt. But it is important to approach
any claims of “educational value” with a
great deal of skepticism.
Whether they are educationally beneficial or not, it is clear
that electronic media are of compelling fascination to infants.
F
E
R
N
A
N
D
O
V
A
Z
Q
U
E
Z
/
G
E
T
T
Y
I
M
A
G
E
S

242 n chapTer 6 DEVELOPMENT OF LANGUAGE AND SYMBOL USE
Putting Words Together
A major landmark in early language development is achieved when children start
combining words into sentences, an advance that enables them to express increas-
ingly complex ideas. The degree to which children develop syntax, and the speed
with which they do it, is what most distinguishes their language abilities from those
of nonhuman primates.
First sentences Most children begin to combine words into simple sentences by
the end of their second year. However, in another example of comprehension pre-
ceding production, young children know something about word combinations well
before they produce any. In one of the first demonstrations of infants’ sensitivity
to word order, Hirsh-Pasek and Golinkoff (1991) showed infants two videotaped
scenes—one of a woman kissing some keys while holding up a ball and the other
of the woman holding up the keys while kissing the ball. Thus, the same three
elements—kissing, keys, and a ball—were present in both scenes. Yet when the
infants heard the sentence “She’s kissing the keys” or “She’s kissing the ball,” they
looked preferentially at the appropriate scene.
Children’s first sentences are two-word combinations; their separate utterances of
“More,” “Juice,” and “Drink” become “More juice” and “Drink juice.” These two-word
utterances have been described as telegraphic speech because, just as in telegrams,
nonessential elements are missing (Brown & Fraser, 1963). Consider the following
examples of standard two-word utterances: “Read me,” “Mommy tea,” “Ride Daddy,”
“Hurt knee,” “All wet,” “More boy,” “Key door,” “Andrew sleep” (Braine, 1976). These
primitive sentences lack a number of elements that would appear in adult utterances,
including function words (such as a, the, in), auxiliary verbs (is, was, will, be), and
word endings (indicating plurals, possessives, or verb
tenses). Children’s early sentences possess this tele-
graphic quality in languages as diverse as English,
Finnish, Dholuo (Kenya), and Kaluli (Papua New
Guinea) (de Boysson-Bardies, 1996/1999). For young
children learning languages like English, in which
word order is crucial for meaning, their early sentences
follow a consistent word order: a child might say “Eat
cookie” but would be unlikely ever to say “Cookie eat.”
Many children continue to produce one- and
two-word utterances for some time, whereas others
quickly move on to sentences consisting of three or
more words. Figure 6.12 shows the rapid increase in
the mean length of utterances of three children in
Roger Brown’s (1973) classic study of language devel-
opment. As you can see from the figure, Eve started
her explosive increase in sentence length much earlier
than the other two children did. The length of chil-
dren’s utterances increases in part because they begin
to systematically incorporate some of the elements
that were missing from their telegraphic speech.
Once children are capable of producing four-word
sentences, typically at around 2½ years of age, they
begin to produce complex sentences containing more
than one clause (Bowerman, 1979): “Can I do it when
we get home?” “I want this doll because she’s big”
(Limber, 1973).
16 18 20 22 24 26 28 30 32 34 36 38 40 42 44
Age (in months)
M
ea
n
l
en
gt
h
o
f
u
tt
er
an
ce
(
in
m
or
p
h
em
es
)
1.50
1.60
1.70
1.80
1.90
2.00
2.10
2.20
2.30
2.40
2.50
2.60
2.70
2.80
2.90
3.00
3.10
3.20
3.30
3.40
3.50
3.60
3.70
3.80
3.90
4.00
4.10
4.20
4.30
Eve Adam Sarah
FIGURE 6.12 Length of utterance This
graph shows the relation between age and
the mean length of utterance for the three
children—adam, eve, and Sarah—studied
telegraphic speech n the term
describing children’s first sentences that
are generally two-word utterances

L A N G U A G E D E V E L O P M E N T n 243
Grammar: a tool for building new words and sentences As noted at the begin-
ning of this chapter, human languages are generative: through the use of the finite
set of words and morphemes in their native vocabulary, individuals can create an
infinite number of sentences and express an infinite number of ideas. Each lan-
guage has a particular set of rules (and exceptions) that governs how linguistic ele-
ments can be combined. The power of language derives from the mastery of these
regularities, which allows individuals to produce and understand language beyond
the specific words and sentences to which they have been exposed. How does this
mastery come about, especially in the early years of life?
Much of the research on this topic has focused on morphemes that are added
to nouns and verbs. In English, nouns are made plural by adding–s, and verbs are
put into the past tense by adding–ed, with some notable exceptions (e.g., men,
went). Young children recognize these formations and are able to generalize them
to novel words. In a classic experiment by Berko (1958), for example, preschool-
ers were shown a picture of a nonsense animal, which the experimenter referred to
as “a wug.” Then a picture of two of the creatures was produced, and the experi-
menter said, “Here are two of them; what are they?” Children as young as 4 read-
ily answered correctly: “Wugs.” Since the children had never heard the word wug
before, their ability to produce the correct plural form for this totally novel word
demonstrated that they could generalize beyond the other plurals they had previ-
ously heard. The results of this study are taken as evidence that the participants
understood how English pluralization works.
Evidence for generalization also comes from the way children treat irregular
cases. Consider the plural of man and the past tense of go. Children initially use
the correct irregular forms of these words, saying “men” for the plural of man and
“went” for the past tense of go. However, they then start making occasional over­
regularization errors, in which they treat irregular forms as if they were regular. For
instance, a child who previously said “men” and “went” may begin producing novel
forms such as “mans” and “goed,” as well as “foots,” “feets,” “breaked,” “broked,” and
even “branged” and “walkeded” (Berko, 1958; Kuczaj, 1977; Xu & Pinker, 1995).
Before eventually mastering irregular forms, children sometimes alternate between
these overregularization errors and correct irregular forms (Marcus, 1996; 2004).
The following dialogue between a 2½-year-old and his father illustrates this kind
of error, as well as the difficulty of correcting it:
Child: I used to wear diapers. When I growed up (pause)
Father: When you grew up?
Child: When I grewed up, I wore underpants.
(Clark, 1993)
Parents play a role in their children’s grammatical development, although a more
limited one than you might expect. Clearly, they provide a model of grammatically
correct speech. In addition, they frequently fill in missing parts of their children’s
incomplete utterances, as when a parent responds to “No bed” by saying, “You
really don’t want to go to bed right now, do you?”
One might think that parents also contribute to their children’s language de-
velopment by correcting their grammatical errors. In fact, parents generally ignore
even wildly ungrammatical mistakes, accepting sentences such as “I magicked it,”
“Me no want go,” or “I want dessert in front of dinner” (Bryant & Polkosky, 2001;
Brown & Hanlon, 1970). It would be hard to do otherwise, since so much of chil-
dren’s speech is like this. And, as the parent who tried to correct his son’s use of
“growed” discovered, such efforts are largely futile anyway. In general, parents are
more likely to correct factual errors than grammatical errors.
overregularization n speech errors in
which children treat irregular forms of
words as if they were regular

244 n chapTer 6 DEVELOPMENT OF LANGUAGE AND SYMBOL USE
Given this lack of correction, how do infants figure out the ways in which the
syntax of their native language works? One approach to answering this question in
the lab involves creating miniature languages—known as artificial grammars—and
determining which types of linguistic patterns infants are able to learn. After just
brief exposure, infants as young as 8 months can learn fairly complex patterns, gen-
eralizing beyond the specific items they have heard (e.g., Gerken, Wilson, & Lewis,
2005; Gómez, 2002; Lany & Saffran, 2010; Marcus et al., 1999; Saffran et al.,
2008). For example, infants who have heard a list of three-word sequences in which
the second word is repeated, such as “le di di, wi je je, de li li . . .” recognize the pat-
tern when it is presented in new syllables, such as “ko ga ga” (Marcus et al., 1999).
Ongoing research focuses on the degree to which these laboratory studies are tap-
ping into the same processes that infants use to acquire native language syntax.
Learning how to combine words to create interpretable sentences is the crown-
ing achievement in language acquisition. Possibly no linguistic development is
more stunning than the progress children make in a few years from simple two-
word utterances to grammatically correct complex sentences. Even their errors
reveal an increasingly sophisticated understanding of the structure of their native
language. This accomplishment is made all the more impressive given the relative
lack of parental feedback they receive. The manner in which this learning unfolds
is the focus of current research.
Conversational Skills
Although young children are eager to participate in conversations with others,
their conversational skills lag well behind their burgeoning language skills. For
one thing, much of very young children’s speech is directed to themselves, rather
than to another person. And this is true not just in solitary play: as much as half of
young children’s speech in the company of other children or adults is addressed to
themselves (Schoeber-Peterson & Johnson, 1991). Vygotsky ((1934/1962) believed
that this private speech of young children serves an important regulatory function:
children talk to themselves as a strategy to organize their actions (Behrend, Rosen-
gren, & Perlmutter, 1992). Gradually, private speech is internalized as thought, and
children become capable of mentally organizing their behavior, so they no longer
need to talk out loud to themselves.
As noted in Chapter 4, when young children converse with other children, their
conversations tend to be egocentric. Piaget (1923/1926) labeled young children’s
talk with their peers as collective monologues. Even when they take turns speak-
ing, their conversations tend to be a series of non sequiturs, with the content of
each child’s turn having little or nothing to do with what the other child has just
said. The following conversation between two preschoolers is a good example of
what Piaget observed:
Jenny: My bunny slippers . . . are brown and red and sort of yellow and white.
And they have eyes and ears and these noses that wiggle sideways when
they kiss.
Chris: I have a piece of sugar in a red piece of paper. I’m gonna eat it but
maybe it’s for a horse.
Jenny: We bought them. My mommy did. We couldn’t find the old ones.
These are like the old ones. They were not in the trunk.
Chris: Can’t eat the piece of sugar, not unless you take the paper off.
(Stone & Church, 1957, pp. 146–147)
Gradually, children’s capacity for sustained conversation increases. In a longi-
tudinal study of parent–child conversations of four children from the age of 21
collective monologue n conversation
between children that involves a series of
non sequiturs, the content of each child’s
turn having little or nothing to do with
what the other child has just said

L A N G U A G E D E V E L O P M E N T n 245
months to 36 months, Bloom, Rocissano, and Hood (1976) found that the propor-
tion of children’s utterances that were on the same topic and added new informa-
tion to what an adult had just said more than doubled (from around 20% to more
than 40%). In contrast, the proportion of utterances on unrelated topics fell dra-
matically (from around 20% to almost 0).
A particular aspect of young children’s conversations that changes dramatically
in the preschool period is the extent to which they talk about the past. At most,
3-year-olds’ conversations include occasional brief references to past events. In
contrast, 5-year-olds produce narratives—descriptions of past events that have the
form of a story (Miller & Sperry, 1988; K. Nelson, 1993). One thing that makes
longer, more coherent narratives possible is better understanding of the basic struc-
ture of stories (Peterson & McCabe, 1988; Shapiro & Hudson, 1991; Stein, 1988).
Parents actively assist their children to develop the ability to produce coherent
accounts of past events by providing what has been referred to as scaffolding (dis-
cussed in Chapter 4) for their children’s narratives (Bruner, 1975). An effective
way to structure children’s conversations about the past is to ask them elaborative
questions, that is, questions that enable them to say something—anything—that
advances the story:
Mother: And what else happened at the celebrations?
Child: I don’t know.
Mother: We did something special with all the other children.
Child: What was it?
Mother: There were a whole lot of people over at the beach, and everyone was
doing something in the sand.
Child: What was it?
Mother: Can’t you remember what we did in the sand? We were looking for
something.
Child: Umm, I don’t know.
Mother: We went digging in the sand.
Child: Umm, and that was when um the yellow spade broke.
Mother: Good girl, I’d forgotten that. Yes, the yellow spade broke, and what
happened?
Child: Um, we had to um dig with the other end of the yellow bit one.
Mother: That’s right. We used the broken bit, didn’t we?
Child: Yeah.
(Farrant & Reese, 2002)
The child in this conversation does not actually say much, but
the parent’s questions help the child think about the event, and
the parent also provides a conversational model. Those toddlers
whose parents scaffold their early conversations by asking use-
ful, elaborative questions produce better narratives on their own a
few years later (Fivush, 1991; McCabe & Peterson, 1991; Reese
& Fivush, 1993).
A crucial aspect of becoming a good conversational partner is
the pragmatic development that allows children to understand how
language is used to communicate. Such understanding is essen-
tial with utterances that require listeners to go beyond the words
they are hearing to grasp their actual meaning—as in instances
of rhetorical questioning, sarcasm, irony, and the use of hyperbole
or understatement to make a point. Children’s pragmatic abilities
develop over the course of the preschool years, facilitating com-
munication with adults and peers. In particular, they learn to take
parents typically help young children talk
about past events. Such conversations con-
tribute to early language development.
JE
F
F
G
R
E
E
N
B
E
R
G
/
P
H
O
T
O
E
D
IT
narratives n descriptions of past events
that have the basic structure of a story

246 n chapTer 6 DEVELOPMENT OF LANGUAGE AND SYMBOL USE
the perspective of their conversational partner, something that is clearly lacking in
the example of the “conversation” between preschoolers Jenny and Chris, quoted
earlier. Kindergarten-aged listeners are able to make use of a conversational part-
ner’s perspective (e.g., by considering what information relevant to the conversa-
tion the partner does or doesn’t have) to figure out what the partner means, and
to provide a pertinent response (Nadig & Sedivy, 2002; Nilsen & Graham, 2009).
The development of this ability is related to children’s level of executive func-
tion; as children become more able to control their tendency to assume their own
perspective, it becomes easier for them to take the perspective of a conversational
partner.
Children also learn to use information other than words to interpret meaning.
For example, older preschoolers can exploit the vocal affect of an ambiguous state-
ment to figure out a speaker’s intention (Berman, Chambers, & Graham, 2010).
When presented with two dolls—one intact, the other broken—and directed to
“Look at the doll,” 4-year-olds (but not 3-year-olds) looked at the intact doll when
the instruction was given with positive affect, and at the broken doll when the in-
struction was given with negative affect.
We thus see that young children put their burgeoning linguistic skills to good
use, becoming more effective communicative partners. Initially, they need substan-
tial support from a more competent partner, but their conversational skills increase
quite regularly. Children’s growing understanding of narrative structure and their
emerging ability to take other people’s perspectives are crucial components in the
development of their conversational skills.
Later Development
From 5 or 6 years of age on, children continue to develop language skills, although
with less dramatic accomplishments. For example, the ability to sustain a conversa-
tion, which grew so dramatically in the preschool years, continues to improve into
adulthood. School-aged children become increasingly capable of reflecting upon
and analyzing language, and they master more complex grammatical structures,
such as the use of passive constructions.
One consequence of schoolchildren’s more reflective language skills is their in-
creasing appreciation of the multiple meanings of words, which is responsible for
the emergence of the endless series of puns, riddles, and jokes with which they
delight themselves and torture their parents (Ely & McCabe, 1994). They also
are able to learn the meaning of new words simply from hearing them defined
(Pressley, Levin, & McDaniel, 1987), a factor that helps their comprehension vo-
cabulary expand—from the 10,000 words that the average 6-year-old knows to
the 40,000 words estimated for 5th graders (Anglin, 1993) to the average college-
student vocabulary that has been estimated to be as high as 150,000 words (Miller
& Gildea, 1987).
Theoretical Issues in Language Development
As you have seen throughout this chapter, there is ample evidence for both nature
and nurture in the process of language development. The two key prerequisites for
language acquisition are (1) a human brain and (2) experience with a human lan-
guage. The former clearly falls on the side of nature, and the latter, on the side of
nurture. Despite the obvious interaction between the two, the nature–nurture de-
bate continues to rage fiercely in the area of language development. Why?

L A N G U A G E D E V E L O P M E N T n 247
Chomsky and the Nativist View
The study of language development emerged from a theoretical debate about the
processes through which language is acquired. In the 1950s, B. F. Skinner (1957)
wrote a book entitled Verbal Behavior, in which he presented a behaviorist theory of
language development. As you saw in Chapter 1, behaviorists believed that devel-
opment is a function of learning through reinforcement and punishment of overt
behavior. Skinner argued that parents teach children to speak by means of the same
kinds of reinforcement techniques that are used to train animals to perform novel
behaviors.
In what was probably the most influential book review ever published, Noam
Chomsky (1959) countered Skinner by pointing out some of the reasons why lan-
guage cannot be learned through the processes of reinforcement and punishment.
One key reason was noted earlier in this chapter: we can understand and pro-
duce sentences that we have never heard before (generativity). If language-learning
according to language theorist Noam chomsky, all these children rely on
the same innate linguistic structures in acquiring their various languages.
TA
X
I
/
G
E
T
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Y
I
M
A
G
E
S
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IC
H
A
R
D
L
O
R
D
/
T
H
E
I
M
A
G
E
W
O
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K
S
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A
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A
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U
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F
/
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A
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248 n chapTer 6 DEVELOPMENT OF LANGUAGE AND SYMBOL USE
proceeds by means of reinforcement and punishment, how could we know that
a sentence like “Colorless green ideas sleep furiously” is a grammatical English
sentence, whereas “Green sleep colorless furiously ideas” is not (Chomsky, 1957)?
Similarly, how could children produce words they have never heard before, like
wented or mouses? The explanation of such instances must be that we know details
about the structure of our native language that we have not been taught—facts that
are unobservable and thus impossible to reinforce—contrary to Skinner’s proposal.
In his own explanation of language development, Chomsky proposed that hu-
mans are born with a Universal Grammar, a hard-wired set of principles and rules
Universal Grammar n a proposed set
of highly abstract, unconscious rules that
are common to all languages
People around the world spontaneously ac-
company their speech with gestures. The
naturalness of gesturing is revealed by the
fact that blind people gesture as they speak
just as much as sighted individuals do, even
when they know their listener is also blind
(Iverson & Goldin-Meadow, 1998).
Gesturing starts early: infants often pro-
duce recognizable, meaningful gestures
before they speak recognizable words. Ac-
cording to Acredolo and Goodwyn (1990),
many “baby signs” are invented by chil-
dren themselves. One child in their research
signed “alligator” by putting her hands to-
gether and opening and closing them to imi-
tate snapping jaws; another indicated “dog”
by sticking her tongue out as if panting; an-
other signaled “flower” by sniffing. Infants
gain earlier motor control of their hands
than of their vocal apparatus, facilitating the
use of signs during the first year.
Interestingly, there is a relationship be-
tween early gesturing and later vocabulary
(M. L. Rowe, Ozcaliskan, & Goldin-Meadow,
2008). The more children gestured at 14
months, the larger their spoken vocabulary
was at 42 months. Moreover, differences in
the amount of gesturing by high- and low-
SES families are one factor that influences
the SES effects discussed in Box 6.2 (M. L.
Rowe & Goldin-Meadow, 2009).
Especially dramatic evidence of intimate
connections between gesture and language
comes from remarkable research on children
who have created their own gesture-based
languages. Goldin-Meadow and colleagues
studied congenitally deaf American and
Chinese children whose hearing parents
had little or no proficiency in any formal
sign language (Feldman, Goldin-Meadow,
& Gleitman, 1978; Goldin-Meadow, 2003;
Goldin-Meadow & Mylander, 1998). These
children and their parents created “home
signs” in order to communicate with one an-
other, and the children’s gesture vo-
cabulary quickly outstripped that of
their parents.
More important, the children (but not
the parents) spontaneously imposed a
structure—a rudimentary grammar—
on their gestures. Both groups of chil-
dren used a grammatical structure
that occurs in some languages but not
those of their parents. As a result, the
sign systems of the children were more
similar to one another than to those of
their own parents. The children’s signs
were also more complex than those of
their parents. A similar phenomenon
occurs when deaf children are learning
to sign from parents who themselves
learned a conventional sign language,
like ASL, but whose signing is ungram-
matical (usually because they learned
to sign later in life). In such cases, deaf
children have been reported to sponta-
neously impose structure that is more
consistent than the signs that their par-
ents produce (Singleton & Newport,
2004).
The most extensive and extraordinary
example of language creation by children
comes from the invention of Nicaraguan
Sign Language (NSL), a completely new lan-
guage that has been evolving over the past
30 years. In 1979, a large-scale education
program for the deaf began in Nicaragua
(Senghas & Coppola, 2001). The program
brought hundreds of deaf children together
BOX 6.4: a closer look
“I JUST CAN’T TALK WITHOUT MY HANDS”:
WHAT GESTURES TELL US ABOUT LANGUAGE
78%
This young participant in the research of acredolo
and Goodwyn is producing her idiosyncratic “baby
sign” for pig.
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L A N G U A G E D E V E L O P M E N T n 249
that govern grammar in all languages. Chomsky’s account, which has been central
to the development of the modern discipline of linguistics, is consistent with the
fact that, despite many surface differences, the underlying structures of the world’s
languages are fundamentally similar. His strongly nativist account also provides an
explanation for why most children learn language with exceptional rapidity, while
nonhumans (who presumably lack a Universal Grammar) do not. (The Univer-
sal Grammar hypothesis has been highly relevant to investigations of emerging
languages like the Nicaraguan Sign Language discussed in Box 6.4, a language in
which children are creating new grammatical structures.)
Nicaraguan deaf children signing together in the language that has emerged in their school
community.
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in two schools in the city of Managua. For
most of the children, it was their first expo-
sure to other deaf people.
The teachers in the schools knew no for-
mal sign language, nor did the children, who
had only the simple home signs they had
used to communicate with their families.
The children quickly began to build on one
another’s existing informal signs, construct-
ing a “pidgin” sign language—a relatively
crude, limited communication system. The
language was used by the students, both
in and outside school, and was learned by
each new group of children who entered the
community.
What happened next was astonishing.
As younger students entered the schools,
they rapidly mastered the rudimentary sys-
tem used by the older students and then
gradually transformed it into a complex,
fully consistent language (NSL) with its own
grammar. The most fluent signers in the
NSL community are currently the youngest
children, both because NSL has evolved into
a real language and because they acquired it
at an earlier age.
Recently, another emerging signed lan-
guage was discovered in the Negev desert
of Israel (Sandler et al., 2005). The Al-
Sayyid Bedouin Sign Language (ABSL) is in
its third generation and is about 75 years
old. Unlike NSL, ABSL is acquired from
birth, because deaf children in this commu-
nity typically have at least one deaf adult
in their extended family. The grammatical
structure of ABSL does not resemble those
of the local spoken languages (Arabic and
Hebrew).
These reports of language invention by
deaf children are not just fascinating sto-
ries: they provide evidence for the child’s
contribution to language learning. Over sev-
eral generations, children have been tak-
ing improvised signing that is simple and
inconsistent and transforming it into struc-
tures much closer to those observed in
established languages. Whether this pro-
cess reflects the operation of a Chomsky-
style Universal Grammar or the operation of
more general learning mechanisms remains
unknown. Regardless, the discovery that
children go beyond the linguistic input they
receive, spontaneously refining and system-
atizing these emerging languages, is one of
the most fascinating findings in the field of
language development.

250 n chapTer 6 DEVELOPMENT OF LANGUAGE AND SYMBOL USE
Ongoing Debates in Language Development
Current theories all acknowledge some of Chomsky’s crucial observations. For
example, any account of language development must be able to explain why all
human languages share so many characteristics. Theories must also explain how it
is that language users, from infants to adults, are able to generalize beyond the spe-
cific words and sentences they have been exposed to. But the ways in which various
accounts handle these facts differ along two key dimensions. The first dimension
is the degree to which these explanations lie within the child (nature) versus within
the environment (nurture). The second dimension pertains to the child’s contri-
butions: Did the cognitive and neural mechanisms underlying language learning
evolve solely to support language learning (domain-specific), or are they used for
learning many different kinds of things (domain-general)?
With respect to the first dimension, theorists have countered Chomsky’s argu-
ment about the universality of language structure by pointing out that there are
also universals in children’s environments. Parents all over the world need to com-
municate about certain things with their children, and these things are likely to be
reflected in the language that children learn. For example, recall Table 6.1, which
shows the remarkable overlap in the earliest words acquired across three diverse
cultures (Tardif et al., 2008). These similarities reflect what parents want to talk
about with their infants, and what infants want to communicate about.
Indeed, accounts focused on social interaction maintain that virtually every-
thing about language development is influenced by its communicative func-
tion. Children are motivated to interact with others, to communicate their own
thoughts and feelings, and to understand what other people are trying to commu-
nicate to them (Bloom, 1991; Bloom & Tinker, 2001; Snow, 1999). According to
this position, children gradually discover the underlying regularities in language
and its use by paying close attention to the multitude of clues available in the lan-
guage they hear, the social context in which language is used, and the intentions
of the speaker (e.g., Tomasello, 2008). Some of these conventions may be learned
by the same kinds of reinforcement methods originally proposed by Skinner. For
example, Goldstein and colleagues have found that both the sounds infants make
when babbling and the rate at which they produce them can be influenced by pa-
rental reinforcement, such as smiling and touching in response to the babbling
(Goldstein, King, & West, 2003; Goldstein & Schwade, 2008). Whether these
types of social behaviors can influence less overt aspects of language development,
such as the acquisition of syntax, remains unclear.
What of the second dimension—the domain-specificity of the processes un-
derlying language acquisition? According to the strongly nativist view espoused
by Chomsky, the cognitive abilities that support language development are highly
specific to language. As Steven Pinker (1994) describes it, language is “a distinct
piece of the biological makeup of our brains . . . distinct from more general abilities
to process information or behave intelligently” (p. 18). This claim is taken one step
further by the modularity hypothesis, which proposes that the human brain con-
tains an innate, self-contained language module that is separate from other aspects
of cognitive functioning (Fodor, 1983). The idea of specialized mental modules is
not limited to language. As you will see in Chapter 7, innate, special-purpose mod-
ules have been proposed to underlie a variety of functions, including perception,
spatial skills, and social understanding.
An alternative view suggests that the learning mechanisms underlying language
development are actually quite general. Although these learning abilities might be
innate, their evolutionary development was not restricted to language learning. For
modularity hypothesis n the idea
that the human brain contains an innate,
self-contained language module that is
separate from other aspects of cognitive
functioning

L A N G U A G E D E V E L O P M E N T n 251
example, researchers have demonstrated that the distributional learning mecha-
nisms discussed earlier in this chapter also help infants track sequences of musi-
cal notes, visual shapes, and human actions (e.g., Fiser & Aslin, 2001; Kirkham,
Slemmer, & Johnson, 2002; Roseberry et al., 2011; Saffran et al., 1999). Similarly,
the fast-mapping mechanisms that support rapid word learning are also used by
toddlers to learn facts about objects (Markson & Bloom, 1997). Also relevant is the
fact that the “less is more” hypothesis for the critical period for language develop-
ment, discussed earlier in this chapter, is not tied specifically to language (Newport,
1990). The ability to extract small chunks of information is likely useful in other
domains as well, such as music, which also consists of small pieces (notes, chords)
organized into higher-level structures (melody, harmony). Finally, recent theories
concerning developmental language disorders (discussed in Box 6.5) invoke aspects
of general cognitive function, not just language.
Throughout this chapter, we have empha-
sized both what is similar and what diverges
across children and across cultures over the
course of language development. The most
significant individual differences fall under
the category of developmental language
disorders. These range from delays that
often disappear by school age to life-long
challenges.
Estimates of the number of preschoolers
with language disorders range from 2% to
19% (H. D. Nelson et al., 2006). The size of
this range reflects the fact that language dis-
orders are often not diagnosed until a child
enters school. Of this group, many of the chil-
dren are considered late talkers. This label is
applied to toddlers who are developing typi-
cally in other domains but whose vocabulary
development is lagging at or below the 10th
percentile. Some of these children are so-
called “late bloomers” who will go on to have
normal or near-normal language skills. Re-
cent research shows that late-talking toddlers
with better word recognition skills are the
most likely to catch up (Fernald & Marchman,
2012). Children who fail to catch up—
roughly 7% of school-aged children in the
United States—are diagnosed with specific
language impairment (SLI). These children
exhibit challenges in many language-related
tasks, including speech perception, word seg-
mentation, and grammatical comprehension
(e.g., Evans, Saffran, & Robe-Torres, 2009;
Fonteneau & van der Lely, 2008; Rice,
2004; Ziegler et al., 2005). They may also
exhibit more general challenges in working
memory, sequence learning, and processing
speed (e.g., Leonard et al., 2007; Tomblin,
Mainela-Arnold, & Zhang, 2007).
Children diagnosed with Down syndrome,
fragile-X syndrome, or autism spectrum dis-
orders (ASD) tend to be significantly delayed
across all aspects of language development,
including both language production and
comprehension. Indeed, challenges in com-
munication are one of the diagnostic cri-
teria for ASD. For children with ASD, early
language abilities are predictive of later out-
comes, including response to treatment (e.g.,
Stone & Yoder, 2001; Szatmari et al., 2003).
Interestingly, younger siblings of children
with ASD, who are themselves at greater risk
for ASD, have a higher rate of language delay
than do their peers (Gamliel et al., 2009).
Another group of children who may de-
velop language disorders are deaf children.
As we noted earlier, if these children have
early exposure to a natural sign language like
ASL, they will follow a typical language de-
velopment trajectory. However, 90% of deaf
children are born to hearing parents, and
many of these children do not have access
to sign language. In the absence of hear-
ing, it is very difficult to learn a spoken lan-
guage. An increasingly popular intervention
for profoundly deaf infants, children, and
adults is the use of cochlear implants (CIs),
surgically implanted devices that translate
auditory input into electrical stimulation of
the auditory nerve. The signal that CIs pro-
vide is quite degraded relative to typical
acoustic hearing. Nevertheless, many deaf
infants and children are able to learn spoken
language with the help of CIs, though the
level of success varies widely across indi-
viduals. Consistent with other critical-period
findings, implantation at a young age (e.g.,
prior to age 3) is better than at later ages
(e.g., Houston & Miyamoto, 2010). Even at
the outset of learning, though, deaf infants
and toddlers who perceive speech through
CIs are less accurate and slower to recognize
words than are their hearing peers (Grieco-
Calub, Litovsky, & Saffran, 2009). Providing
these learners with bilingual input (natural
sign language and spoken language through
CIs) may offer the most successful route to
language acquisition.
BOX 6.5: individual differences
DEVELOPMENTAL LANGUAGE DISORDERS
cochlear implants are a surgically implanted
device used by some deaf and hearing-
impaired individuals.
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252 n chapTer 6 DEVELOPMENT OF LANGUAGE AND SYMBOL USE
As in other areas of child development, computational modeling has played an
important role in the development of modern theoretical perspectives. By using
computational models, researchers can specify both the innate structure and the
environmental input to a computerized learner and attempt to determine what is
crucial when simulating children’s language acquisition. One influential perspective
oriented around computational modeling is connectionism, a type of information-
processing theory that emphasizes the simultaneous activity of numerous inter-
connected processing units. Connectionist researchers have developed computer
simulations of various aspects of cognitive development, including language ac-
quisition (e.g., Elman et al., 1996). The software learns from experience, gradually
strengthening certain connections among units in ways that mimic children’s devel-
opmental progress. Connectionist accounts have achieved impressive success with
respect to modeling specific aspects of language development, including children’s
acquisition of the past tense in English and the development of the shape bias for
word learning (e.g., Rumelhart & McClelland, 1986; Samuelson, 2002). However,
connectionist models are always open to criticism regarding the features that were
built into the models in the first place (e.g., do they have the same “innate” con-
straints as infants?), and how well the input provided to them matches the input
received by real children.
review:
The process of comprehending and producing language, whether spoken or signed, involves
the development of many different kinds of knowledge and skills. In the space of a few years,
children take giant steps in mastering the phonology, semantics, syntax, and pragmatics of
their native language. This remarkable achievement is made possible by the joint prerequi-
sites of a human brain and exposure to human communication.
The current theoretical accounts of language development differ with respect to how much
emphasis they put on nature and nurture. Nativists like Chomsky emphasize innate linguistic
knowledge and language-specific learning mechanisms, whereas other theorists argue that
language learning can emerge from general-purpose learning mechanisms. Children’s moti-
vation to understand and interact with other people is also central to many theories. The vast
literature on language development provides some support for all of these views, but none
of them provide the full story of children’s acquisition of this vastly complex and arguably
unique of all human abilities.
Nonlinguistic Symbols and Development
Although language is our preeminent symbol system, humans have invented a
wealth of other kinds of symbols to communicate with one another. Virtually any-
thing can serve as a symbol so long as someone intends it to stand for something
other than itself (DeLoache, 2002, 2004). The list of symbols you regularly en-
counter is long and varied, ranging from the printed words, numbers, graphs, pho-
tographs, and drawings in your textbooks to thousands of everyday items such as
computer icons, maps, clocks, and so on. Because symbols are so central to our ev-
eryday lives, mastering the symbol systems important in their culture is a crucial
developmental task for all children.
Symbolic proficiency involves both the mastery of the symbolic creations of oth-
ers and the creation of new symbolic representations. We will first discuss early sym-
bolic functioning, starting with research on very young children’s ability to exploit
the informational content of symbolic artifacts. Then we will focus on children’s
connectionism n a type of information-
processing approach that emphasizes the
simultaneous activity of numerous inter-
connected processing units
dual representation n the idea that
a symbolic artifact must be represented
mentally in two ways at the same time—
both as a real object and as a symbol for
something other than itself

N O N L I N G U I S T I C S Y M B O L S A N D D E V E L O P M E N T n 253
creation of symbols through drawing. In Chapter 7, we will consider chil-
dren’s creation of symbolic relations in pretend play, and in Chapter 8, we
will examine older children’s development of two of the most important
of all symbolic activities—reading and mathematics.
Using Symbols as Information
One of the vital functions of many symbols is that they provide useful
information. For example, a map—whether a crude pencil sketch on the
back of an envelope or a Google map on your smartphone—can be cru-
cial for locating a particular place. To use a symbolic artifact such as a
map requires dual representation; that is, the artifact must be represented
mentally in two ways at the same time, as a real object and as a symbol for
something other than itself (DeLoache, 2002, 2004).
Very young children have substantial difficulty with dual represen-
tation, limiting their ability to use information from symbolic artifacts
(DeLoache, 2004). This has been demonstrated by research in which a
young child watches as an experimenter hides a miniature toy in a scale
model of the regular-sized room next door (Figure 6.13) (DeLoache,
1987). The child is then asked to find a larger version of the toy that the
child is told “is hiding in the same place in the big room.” Three-year-
olds readily use their knowledge of the location of the miniature toy in the
model to figure out where the large toy is in the adjacent room. In contrast,
most 2½-year-old children fail to find the large toy; they seem to have no
idea that the model tells them anything about the full-size room. Because
the model is so salient and interesting as a three-dimensional object, very
young children have trouble managing dual representation and fail to no-
tice the symbolic relation between the model and the room it stands for.
This interpretation received strong support in a study with 2½-year-
old children in which reasoning between a model and a larger space was
not necessary (DeLoache, Miller, & Rosengren, 1997). An experimenter
showed each child a “shrinking machine” (really an oscilloscope with lots
of dials and lights) and explained that the machine could “make things
get little.” The child watched as a troll doll was hidden in a movable tent-
like room (approximately 8 feet by 6 feet) and the shrinking machine was
“turned on.” Then the child and experimenter waited in another room
while the shrinking machine did its job. When they returned, a small-scale
model of the tentlike room stood in place of the original. (Assistants had,
of course, removed the original tent and replaced it with the scale model.)
When asked to find the troll, the children succeeded.
Why should the idea of a shrinking machine enable these 2½-year-
olds to perform the task? The answer is that if a child believes the experimenter’s
claims about the shrinking machine, then in the child’s mind the model simply is
the room. Hence, there is no symbolic relation between the two spaces and no need
for dual representation.
The difficulty that young children have with dual representation and symbols
is evident in other contexts as well. For example, investigators often use anatomi-
cally detailed dolls to interview young children in cases of suspected sexual abuse,
assuming that the relation between the doll and themselves would be obvious.
However, children younger than 5 years often fail to make any connection between
themselves and the doll, so the use of a doll does not improve their memory reports
FIGURE 6.13 Scale-model task In
a test of young children’s ability to use a
symbol as a source of information, a 3-year-
old child watches as the experimenter (Judy
DeLoache) hides a miniature troll doll under
a pillow in a scale model of an adjacent
room. The child searches successfully for a
larger troll doll hidden in the corresponding
place in the actual room, indicating that
she appreciates the relation between the
model and room. The child also success-
fully retrieves the small toy she originally
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254 n chapTer 6 DEVELOPMENT OF LANGUAGE AND SYMBOL USE
and may even make them less reliable (Bruck et al., 1995; DeLoache & Marzolf,
1995; Goodman & Aman, 1990).
Increasing ability to achieve dual representation—to immediately interpret a
symbol in terms of what it stands for—enables children to discover the abstract
nature of various symbolic artifacts. For example, unlike younger children, school-
aged children realize that the red line on a road map does not mean that the real
road would be red (Liben & Myers, 2007). Older children are also able, when
properly instructed, to use objects such as rods and blocks of different sizes that
represent different numerical quantities to help them learn to do mathematical op-
erations (Uttal, Liu, & DeLoache, 2006).
Drawing
Creating pictures is a common symbolic activity encouraged by parents in many soci-
eties (Goodnow, 1977). When young children first start making marks on paper, their
focus is almost exclusively on the activity per se, with no attempt to produce recogniz-
able images. At around 3 or 4 years or age, most children begin trying to draw pictures
of something; they try to produce representational art (Callaghan, 1999). Exposure
to representational symbols affects the age at which children begin to produce them.
One recent study (Callaghan et al., 2011) found that children from homes filled with
pictorial images (a Canadian sample) produce such images earlier and more often
than children from homes with few such images (Indian and Peruvian samples).
Initially, children’s artistic impulses outstrip their motor and planning capa-
bilities ( Yamagata, 1997). Figure 6.14 shows what at first appears simply to
FIGURE 6.14 early drawing appear-
ances to the contrary, this is not random
scribbling, as shown by what the 2½-year-
old who produced it said about his work. as
he drew a roughly triangular shape, he said
it was a “sailboat.” a set of wavy lines was
labeled “water.” Some scribbled lines under
the “sailboat” were denoted as the “person
driving the boat.” Finally, the wild scrib-
bles all over the rest were “a storm.” Thus,
each element was representational to some
degree, even though the picture as a whole
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N O N L I N G U I S T I C S Y M B O L S A N D D E V E L O P M E N T n 255
be a classic scribble. However, the 2½-year-
old creator of this picture was narrating his
efforts as he drew, making it possible to as-
certain his artistic intentions. While he
represented the individual elements of his
picture reasonably well, he was unable to co-
ordinate them spatially.
The most common subject for young chil-
dren is the human figure (Goodnow, 1977).
Just as infants who are first beginning to
speak simplify the words they produce, young
children simplify their drawings, as shown in
Figure 6.15. Note that to produce these very
simple, crude shapes, the child must plan the drawing and must spatially coor-
dinate the individual elements. Even early “tadpole” people have the legs on the
bottom and the arms on the side—although often emerging from the head.
Figure 6.16 reveals some of the strategies children use to produce more com-
plex pictures. The drawing depicts the route from the artist’s home to the local
grocery store, with several houses along the way. One strategy the child used
was to rely on a well-practiced formula for representing houses: a rectangle with
a door and a roofline. Another was to coordinate the placement of each house
with respect to the road, although at the cost of the overall coordination among
the houses. Eventually, some children become highly skilled at representing the
relations among the multiple elements in their pictures.
review:
Nonlinguistic symbols play an important role in the lives of young children. As they become
increasingly sensitive to the informational potential of symbolic objects created by others,
children take an important step toward skillful use of the many symbol systems that are key
to modern life. A critical factor in understanding and using the symbols created by others
is dual representation—the ability to mentally represent both a symbolic object, such as a
FIGURE 6.16 More complex drawings
This child’s drawing relies on some well-
practiced strategies, but the child has not yet
worked out how to represent complex spatial
relationships.
FIGURE 6.15 Tadpole drawings Young
children’s early drawings of people typically
take a “tadpole” form.

256 n chapTer 6 DEVELOPMENT OF LANGUAGE AND SYMBOL USE
map or model, and its relation to what it stands for. The ability to create symbols is evident
in young children’s drawings.
chapter summary:
A critical feature of what it means to be human is the creative
and flexible use of a variety of languages and other symbols.
The enormous power of language comes from generativity—
the fact that a finite set of words can be used to generate an
infinite number of sentences.
Language Development
n Acquiring a language involves learning the complex system of
phonology, semantics, syntax, and pragmatics that govern its
sounds, meaning, grammar, and use.
n Language ability is species-specific. The first prerequisite for
its full-fledged development is a human brain. Researchers
have succeeded in teaching nonhuman animals remarkable
symbolic skills but not full-fledged language.
n The early years constitute a critical period for language acqui-
sition; many aspects of language are more difficult to acquire
thereafter.
n A second prerequisite for language development is expo-
sure to language. Much of the language babies hear takes
the form of infant-directed speech (IDS), which is char-
acterized by a higher-than-normal pitch; extreme shifts in
intonation; a warm, affectionate tone; and exaggerated facial
expressions.
n Infants have remarkable speech-perception abilities. Like
adults, they exhibit categorical perception of speech sounds,
perceiving physically similar sounds as belonging to discrete
categories.
n Young infants are actually better than adults at discrimi-
nating between speech sounds not in their native language. As
they learn the sounds that are important in their language(s),
infants’ ability to distinguish between sounds in other lan-
guages declines.
n Infants are remarkably sensitive to the distributional properties
of language; they notice a variety of subtle regularities in the
speech they hear and use these regularities to segment words
from fluent speech.
n Infants begin to babble at around 7 months of age, either
repeating syllables (“bababa”) or, if exposed to sign language,
using repetitive hand movements. Gradually, vocal babbling
begins to sound more like the baby’s native language.
n During the second half of the first year, infants are learning
how to interact and communicate with other people, including
developing the ability to establish joint attention.
n Infants begin to recognize highly familiar words at about 6
months of age.
n Infants begin to produce words at around 1 year of age. They
initially say just one word at a time, and often make overexten-
sion errors, using a particular word in a broader context than is
appropriate. Infants make use of a variety of strategies to figure
out what new words mean.
n By the end of their second year, most infants produce short
sentences. The length and complexity of their utterances
gradually increase, and infants spontaneously practice their
emerging linguistic skills.
n In the early preschool years, children exhibit generalization,
extending such patterns as “add–s to make plural” to novel
nouns, and making overregularization errors.
n Children develop their burgeoning language skills as they
go from collective monologues to sustained conversation,
improving their ability to tell coherent narratives about their
experiences.
n All current theories of language development agree that there
is an interaction between innate factors and experience.
n Nativists, such as the influential linguist Noam Chomsky, posit
innate knowledge of “Universal Grammar,” the set of highly
abstract rules common to all languages. They believe that lan-
guage learning is supported by language-specific skills.
n Theorists focused on social interaction emphasize the com-
municative context of language development and use. They
emphasize the impressive degree to which infants and young
children exploit a host of pragmatic cues to figure out what
others are saying.
n Other perspectives argue that language can develop in the
absence of innate knowledge and that language learning
requires powerful general-purpose cognitive mechanisms.
Connectionist models have been used to support this view.

C H A P T E R S U M M A R Y n 257
Nonlinguistic Symbols and Development
n Symbolic artifacts like maps or models require dual representa-
tion. To use them, children must represent mentally both the
object itself as well as its symbolic relation to what it stands for.
Toddlers become increasingly skillful at achieving dual represen-
tation and using symbolic artifacts as a source of information.
n Drawing is a popular symbolic activity. Young children’s early
scribbling quickly gives way to the intention to draw pictures
of something, with a favorite theme being representations of
the human figure.
Critical Thinking Questions
1. Drawing on the many references to parental behaviors rel-
evant to language development that were discussed in this
chapter, give some examples of ways parents are known to
influence their children’s language development.
2. Language development is a particularly complex aspect of
child development, and no single theory successfully accounts
for all that is known about how children acquire language.
Would you weight the child’s contributions (nature) or the
environment’s contributions (nurture) more strongly?
3. What are overregularization errors, and why do they offer
strong evidence for the acquisition of grammatical structures
by children?
4. Many parallels were drawn between the process of language
acquisition in children learning spoken language and in those
learning signed language. What do these similarities tell us
about the basis for human language?
Key Terms
babbling, p. 230
bilingualism, p. 222
categorical perception, p. 224
collective monologues, p. 244
comprehension, p. 217
connectionism, p. 252
critical period, p. 220
distributional properties, p. 228
dual representation, p. 253
fast mapping, p. 236
generativity, p. 217
holophrastic period, p. 234
infant-directed speech (IDS), p. 223
metalinguistic knowledge, p. 218
modularity hypothesis, p. 250
morphemes, p. 217
narratives, p. 245
overextension, p. 234
overregularization, p. 243
phonemes, p. 217
phonological development, p. 217
pragmatic cues, p. 237
pragmatic development, p. 218
production, p. 217
prosody, p. 224
reference, p. 231
semantic development, p. 217
symbols, p. 216
syntactic bootstrapping, p. 239
syntactic development, p. 218
syntax, p. 218
telegraphic speech, p. 242
Universal Grammar, p. 248
voice onset time (VOT), p. 225
word segmentation, p. 228

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J O H N G E O R G E B R O W N ( 1 8 1 3 – 1 9 1 3 ) , The Little Joker

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Conceptual Development
n Understanding Who or What
Dividing Objects into Categories
Knowledge of Other People and Oneself
Box 7.1: Individual Differences Children with Autism
Spectrum Disorders
Box 7.2: Individual Differences Imaginary Companions
Knowledge of Living Things
Review
n Understanding Why, Where, When,
and How Many
Causality
Box 7.3: A Closer Look Magical Thinking and Fantasy
Space
Time
Number
Relations Among Understanding of Space, Time,
and Number
Review
n Chapter Summary
chapter 7:

260
S
hawna, an 8-month-old, crawls into her 7-year-old brother’s bedroom.
The room contains many objects, among them a bed, a dresser, a dog, a
baseball, a baseball mitt, books, magazines, shoes, and dirty socks. To her
older brother, the room includes furniture, clothing, reading material, and
sports equipment. But what does the room look like to Shawna?
Infants lack concepts of furniture, reading material, and sports equipment, and
also lack more specific, relevant concepts such as baseball mitts and books. Thus,
Shawna would not understand the scene in the same way her older brother would.
However, without knowledge of child development research, it would be difficult to
anticipate whether a baby as young as Shawna would have formed other concepts rel-
evant to understanding the scene. Would she have formed concepts
of living and nonliving things that would help her understand why
the dog runs around on its own but the books never do? Would she
have formed concepts of heavier and lighter that would allow her to
understand why she could pick up a sock but not a dresser? Would
she have formed concepts of before and after that would allow her
to understand that her brother always puts on his socks before his
shoes rather than in the opposite order? Or would it all be a jumble?
As this imaginary scene indicates, concepts are crucial for helping
people make sense of the world. But what exactly are concepts, and
how do they help us understand?
Concepts are general ideas that organize objects, events, quali-
ties, or relations on the basis of some similarity. There are an infi-
nite number of possible concepts, because there are infinite ways in
which objects or events can be similar. For example, objects can have
similar shapes (all football fields are rectangular), materials (all diamonds are made of
compressed carbon), sizes (all skyscrapers are tall), tastes (all lemons are sour), colors
(all colas are brown), functions (all knives are for cutting), and so on.
Concepts help us understand the world and act effectively in it by allowing us
to generalize from prior experience. If we like the taste of one carrot, we probably
will like the taste of others. Concepts also tell us how to react emotionally to new
experiences, as when we fear all dogs after being bitten by one. Life without con-
cepts would be unthinkable: every situation would be new, and we would have no
idea what past experience was relevant in the new situation.
Several themes have been especially prominent in research on conceptual de-
velopment. One is nature and nurture: children’s concepts reflect the interaction
between their specific experiences and their biological predispositions to process
information in particular ways. Another recurring theme is the active child: from
infancy onward, many of children’s concepts reflect their active attempts to make
sense of the world. A third major theme is how change occurs: researchers who study
conceptual development attempt to understand not only what concepts children
form but also the processes by which they form them. A fourth is the sociocultural
context: the concepts we form are influenced by the society in which we live.
Although there is widespread agreement that conceptual development reflects
the interaction of nature and nurture, the particulars of this interaction are hotly
debated. The controversy parallels the nativist/empiricist controversies described
previously in the context of perceptual development (page 183) and language devel-
opment (pages 247–252). Nativists, such as Liz Spelke (2011), Alan Leslie (Scholl
& Leslie, 2002), and Karen Wynn (2007) believe that innate understanding of
Themes
n Nature and Nurture
n The Active Child
n Mechanisms of Change
n The Sociocultural Context
What does this infant see when he looks at
this room?
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concepts n general ideas or understand-
ings that can be used to group together
objects, events, qualities, or abstractions
that are similar in some way

U N D E R S T A N D I N G W H o o R W H A T n 261
basic concepts plays a central role in development. They argue that infants are born
with some sense of fundamental concepts, such as time, space, number, causality,
and the human mind, or with specialized learning mechanisms that allow them to
acquire rudimentary understanding of these concepts unusually quickly and eas-
ily. Within the nativist perspective, nurture is important to children’s developing
the concepts beyond this initial level but not for forming the basic understanding.
In contrast, empiricists, such as Vladimir Sloutsky (2010), Scott Johnson (2010),
David Rakison (Rakison & Lupyan, 2008), and Marianella Casasola (2010) argue
that nature endows infants with only general learning mechanisms, such as the
ability to perceive, associate, generalize, and remember. Within the empiricist per-
spective, the rapid and universal formation of fundamental concepts such as time,
space, number, causality, and mind arises from infants’ massive exposure to experi-
ences that are relevant to these concepts. Empiricists also maintain that the data on
which many nativist arguments are based—data involving infants’ looking times in
habituation studies—are not sufficient to support the nativists’ conclusions that in-
fants understand the concepts in question ( J. J. Campos et al., 2008; Kagan, 2008).
The continuing debate between nativists and empiricists reflects a fundamental,
unresolved question about human nature: Do children form all concepts through
the same learning mechanisms, or do they also possess special mechanisms for
forming a few particularly important concepts?
This chapter focuses on the development of fundamental concepts—those that
are useful in the greatest number of situations. These concepts fall into two groups.
One group of fundamental concepts is used to categorize the kinds of things that
exist in the world: human beings, living things in general, and inanimate objects.
The other group of fundamental concepts involves dimensions used to represent
our experiences: space (where the experience occurred), time (when it occurred),
number (how many times it occurred), and causality (why it occurred).
You may have noticed that these fundamental concepts correspond closely to the
questions that every news story must answer: Who or what? Where? When? How
many? Why? The similarity between the concepts that are most fundamental for chil-
dren and those that are most important in news stories is no accident. Knowing who
or what, where, when, how many, and why is essential for understanding any event.
Because early conceptual development is so crucial, this chapter focuses on de-
velopment in the first 5 years. This obviously does not mean that conceptual growth
ends at age 5. Beyond this age, children form vast numbers of more- specialized
concepts, and understanding of all types of concepts deepens for many years there-
after. Rather, the focus here on early conceptual development reflects the fact that
this is the period in which children acquire a basic understanding of the most cru-
cial concepts—the ones that are universal, that allow children to understand their
own and other people’s experiences, and that provide the foundations for subse-
quent conceptual growth.
Understanding Who or What
Dividing Objects into Categories
Beginning early in development, children attempt to understand what kinds of
things exist in the world. They quickly divide the objects they encounter into three
general categories: inanimate objects, people, and other animals (they are unsure for
many years whether plants are more like animals or more like inanimate objects)

262 n chapter 7 CoNCEpTUAL DEVELopMENT
(S. A. Gelman & Kalish, 2006). Forming these broad divisions is crucial, because
different types of concepts apply to different types of objects (Keil, 1979). Some
concepts apply to anything—all things, living and nonliving, have height, weight,
color, size, and so on. Other concepts apply only to living things—only living things
eat, drink, grow, and breathe, for example. Yet other concepts—reading, shopping,
pondering, and talking—apply only to people. Forming these general categories of
objects allows children to draw accurate inferences about unfamiliar entities. For
example, when told that a platypus is a kind of animal, children know immediately
that a platypus can move, eat, grow, reproduce, and so on.
A number of researchers hypothesize that children organize their observations of
these categories into informal theories (e.g., Carey, 2009; G. L. Murphy & Medin,
1985; Vamvakoussi & Vosniadou, 2010). Wellman and Gelman (1998) proposed that
young children or ganize their knowledge of the things in the world into three infor-
mal theories: a theory of physics (inanimate objects), a theory of psychology (people), and
a theory of biology (other living things). These informal theories are viewed as having
an innate core but also as incorporating—and in some cases being radically trans-
formed by—learning processes such as association, observation, and the statements of
other people (S. A. Gelman & Kalish, 2006). These informal theories are rudimen-
tary, but they share three important characteristics with formal scientific theories:
1. They identify fundamental units for dividing all objects and events into a few
basic categories.
2. They explain many phenomena in terms of a few fundamental principles.
3. They explain events in terms of unobservable causes.
Each characteristic is evident in the preschool period (E. M. Evans, 2008; S. A.
Gelman, 2003; Inagaki & Hatano, 2008). Consistent with the first characteristic,
preschoolers divide all objects into people, other animals, plants, and nonliving
things. Consistent with the second characteristic, preschoolers understand broadly
applicable principles—that a desire for food and water underlies many behaviors of
animals, for example. Consistent with the third characteristic, preschoolers know
that many of animals’ vital activities, such as movement and healing from illness,
are caused by something inside the animals as opposed to the external forces that
determine the actions of inanimate objects.
When do children first generate such core theories? Spelke (2003) speculated
that infants begin life with a primitive theory of physics, that is, of inanimate ob-
jects. The theory includes the knowledge that the world contains physical objects
that occupy space, move only in response to external forces, move in continuous
ways through space rather than jumping from one position to another, and cannot
simultaneously occupy the same space as another object.
Wellman and Gelman (1998) suggested that children’s first theory of psychology
emerges at around 18 months of age, and their first theory of biology at around 3
years. The first theory of psychology is organized around the understanding that
other people’s actions reflect their desires. For example, a 2-year-old boy realizes
that his mother will want to eat if she is hungry, regardless of whether the 2-year-
old himself is hungry. The first theory of biology is organized around the realiza-
tion that people and other animals are living things, different from nonliving things
and plants. For example, 3- and 4-year-olds realize that animals, but not inanimate
objects, move under their own power (S. A. Gelman, 2003).
Of course, vast development occurs beyond these initial theories. Some of this
development builds on the original organization and fills in details. As noted in
Chapter 5 (page 207), for instance, even 3-month-olds understand that an object

U N D E R S T A N D I N G W H o o R W H A T n 263
(e.g., a glass) will fall unless at least some part of it is supported by another object
(e.g., a table), but not until about 5 months of age do infants understand that the
object also will fall if only a small portion is supported (Baillargeon, 1994). In other
cases, children may replace rudimentary theories with more advanced ones. Their
initial biological theory distinguishes animals from inanimate objects and plants;
not until the age of 7 years are children convinced that the category living things
includes plants as well as animals (Inagaki & Hatano, 2008).
Just as these theories help children divide objects into broad categories, form-
ing category hierarchies—that is, categories organized according to set–subset
relations—helps children make finer distinctions among the objects within each
category. The furniture/chair/La-Z-Boy example shown in Table 7.1 is one ex-
ample. The category “furniture” includes all chairs; the category “chair” includes
all La-Z-Boys. Forming such category hierarchies greatly simplifies the world for
children by allowing them to draw accurate inferences. Knowing that a La-Z-Boy
is a kind of chair allows children to use their general knowledge of chairs to infer
that people sit on La-Z-Boys and that La-Z-Boys are neither lazy nor boys.
Of course, infants are not born knowing about La-Z-Boys and chairs, nor are
they born knowing the other categories shown in Table 7.1. Thus, one important
question is: How do infants and older children form categories that apply to all
kinds of objects, living and nonliving?
Categorization of Objects in Infancy
Even in the first months of life, infants form categories of objects. P. C. Quinn
and Eimas (1996), for example, found that when they were shown a series of pho-
tographs of very different breeds of cats, 3- and 4-month-olds habituated; that
is, they looked at new cat photographs for less and less time. However, when the
infants were subsequently shown a picture of a dog, lion, or other animal, they
dishabituated; that is, their looking time increased. Their habituation to the cat
photographs suggests that the infants saw all the cats, despite their differences, as
members of a single category; their subsequent dishabituation to the photo of the
dog or other animal suggests that the infants saw those creatures as members of
categories other than cats.
Infants also can form categories more general than “cats.” Behl-Chadha (1996)
found that 6-month-olds habituated after repeatedly being shown pictures of
different types of mammals (dogs, zebras, elephants, and so forth) and then dis-
habituated when they were shown a picture of a bird or a fish. The infants appar-
ently perceived similarities among the mammals that led to their eventually losing
TABLE 7.1
Object hierarchies
Level Type of Object
Most General Inanimate Objects People Living Things
General Furniture, Vehicles . . . Europeans, Asians . . . Animals, Plants . . .
Medium Chairs, Tables . . . Spaniards, Finns . . . Cats, Dogs . . .
Specific La-Z-Boys, Armchairs . . . Picasso, Cervantes . . . Lions, Lynxes . . .
category hierarchy n categories that
are related by set–subset relations, such
as animal/dog/poodle

264 n chapter 7 CoNCEpTUAL DEVELopMENT
interest in them. The infants also apparently perceived differences between the
mammals and the bird or fish that led them to show renewed interest.
As suggested by this example, infants frequently use perceptual categorization,
the grouping together of objects that have similar appearances (L. B. Cohen &
Cashon, 2006; Madole & Oakes, 1999). Prior to participating in the Behl-Chadha
(1996) study, few infants would have seen zebras or elephants. Thus, the distinc-
tions the infants made between these mammals and the birds and fish could only
have been based on perception of the animals’ differing appearances.
Infants categorize objects along many perceptual dimensions, including color,
size, and movement. Often their categorization is largely based on specific parts of
an object rather than on the object as a whole; for example, infants younger than 18
months rely heavily on the presence of legs to categorize objects as animals, and they
rely heavily on the presence of wheels to categorize objects as vehicles ( Rakison &
Lupyan, 2008; Rakison & Poulin-Dubois, 2001).
As children approach their 2nd birthday, they increasingly categorize objects on
the basis of overall shape. As discussed in Chapter 6, when toddlers are shown an
unfamiliar object and told that it is a “dax,” they assume that other objects of the
same shape are also “daxes,” even when the objects differ from each other in size,
texture, and color (Landau, Smith, & Jones, 1998). This is a useful assumption, be-
cause for many objects, shape indeed is similar for different members of a category.
If we see a silhouette of a cat, hammer, or chair, we can tell from the shape what
the object is. However, we rarely can do the same if we know only the object’s color
or size or texture.
Categorization of Objects Beyond Infancy
As children move beyond infancy, they increasingly grasp not only individual cat-
egories but also hierarchical and causal relations among categories.
category hierarchies The category hierarchies that young children form often
include three of the main levels in Table 7.1: the general one, which is called the
superordinate level; the very specific one, called the subordinate level; and the
medium or in-between one, called the basic level (Rosch et al., 1976). As its name
suggests, the basic level is the one that children usually learn first. Thus, they typi-
cally form categories of medium generality, such as “tree,” before they form more
general categories such as “plant” or more specific ones such as “oak.”
The reasons why children generally form the basic level first are not hard to
understand. A basic-level category such as “tree” has a number of consistent char-
acteristics: bark, branches, large size, and so on. In contrast, the more general cat-
egory “plant” has fewer consistent characteristics: plants come in a wide range of
shapes, sizes, and colors (consider an oak, a rose, and a house plant). Subordinate-
level categories have the same consistent characteristics as the basic-level category,
and some additional ones—all oaks, but not all trees, have rough bark and pointed
leaves, for example. However, it is relatively difficult to discriminate among differ-
ent subordinate categories within the same basic-level category (oaks versus ma-
ples, for example). Thus, it is not surprising that children tend to form basic-level
categories first.
Very young children’s basic categories do not always match those of adults. For
example, rather than forming separate categories of cars, motorcycles, and buses,
young children seem to group these objects together into a category of “objects with
wheels” (Mandler & McDonough, 1998). Even in such cases, however, the initial
perceptual categorization n the
grouping together of objects that have
similar appearances
superordinate level n the most general
level within a category hierarchy, such
as “animal” in the animal/dog/poodle
example
subordinate level n the most specific
level within a category hierarchy, such
as “poodle” in the animal/dog/poodle
example
basic level n the middle level, and often
the first level learned, within a category
hierarchy, such as “dog” in the animal/
dog/poodle example

U N D E R S T A N D I N G W H o o R W H A T n 265
categories are less general than such categories as “moving things” and more general
than ones such as “Toyotas.”
Having formed basic-level categories, how do children go on to form superor-
dinate and subordinate categories? Part of the answer is that parents and others
use the child’s basic-level categories as a foundation for explaining the more spe-
cific and more general categories (S. A. Gelman et al., 1998). When parents teach
children superordinate categories such as mammals, they typically illustrate prop-
erties of the relevant terms with basic-level examples that the child already knows
(Callanan, 1990). They might say, “Mammals are animals, like foxes, bears, and
cows, that get milk from their mothers when they are babies.”
Parents also refer to basic-level categories to teach children subordinate-level
terms (Callanan & Sabbagh, 2004; Waxman & Senghas, 1992). For example, a
parent might say, “Belugas are a kind of whale.” Preschoolers are sensitive to the
nuances of such statements; for example, they generalize more widely from categor-
ical statements such as “Belugas are a kind of whale” than from statements about
specific objects, such as “This beluga is a whale” (Cimpian & Scott, 2012). Thus,
statements that specify relations among categories of objects allow children to use
what they already know about basic-level categories to form superordinate- and
subordinate-level categories.
Although parents’ explanations clearly enhance children’s conceptual under-
standing, the learning path sometimes involves amusing detours. In one such case,
Susan Gelman (2003) gave her 2-year-old son a spoon and a container filled with
bite-size pieces of fruit and said, “This is a fruit cup.” The boy responded to her de-
scription by picking up the “cup” and attempting to drink from it. Children’s active
attempts to understand their experiences lead to many short-lived but interesting
concepts such as the “fruit cup.”
causal understanding and categorization Toddlers and preschoolers are noto-
rious for their endless questions about causes and reasons. “Why do dogs bark?”
“How does the iPhone know where to call?” “Where does rain come from?”
Although parents are often exasperated by such questions, their respecting and
answering the inquiries help children learn (Chouinard, 2007).
Understanding causal relations is crucial in forming many categories. How could
children form the category of “light switches,” for example, if they did not under-
stand that flipping certain objects causes lights to go on and off? To study how an
understanding of causes and effects influences category formation, Krascum and
Andrews (1998) told 4- and 5-year-olds about two categories of imaginary animals:
wugs and gillies. Some of the preschoolers were provided only physical descriptions
of the animals: they were told that wugs usually have claws on their feet, spikes on
the end of their tails, horns on their heads, and armor on their backs; gillies were
described as usually having wings, big ears, long tails, and long toes. Other chil-
dren were provided the same physical descriptions, plus a simple causal story that
explained why wugs and gillies are the way they are. These children were told that
wugs have claws, spikes, horns, and armor because they like to fight. Gillies, in con-
trast, do not like to fight; instead, they hide in trees. Their big ears let them hear
approaching wugs, their wings let them fly away to treetops, and so on. After the
children in both groups were given the information about these animals, they were
shown the pictures in Figure 7.1 and asked which animal was a wug and which
animal was a gilly.
The children who were told why wugs and gillies have the physical features they
do were better at classifying the pictures into the appropriate categories. When

266 n chapter 7 CoNCEpTUAL DEVELopMENT
tested the next day, those children also remembered the cat-
egories better than did the children who were given the physi-
cal descriptions without explanations. Thus, understanding
cause–effect relations helps children learn and remember new
categories.
Knowledge of Other People and Oneself
Although the understanding of oneself and others varies
greatly from individual to individual, just about everybody has
a commonsense level of psychological understanding. This
naïve psychology is crucial to normal human functioning and
is a major part of what makes us people. Adult chimpanzees
are the equal of human 2½-year-olds on a wide range of tasks
that require physical reasoning, such as how to use tools to obtain food, but fall far
short of the toddlers on tasks requiring social reasoning, such as inferring inten-
tions from behavior (Herrmann, et al., 2007; Tomasello, 2008).
At the center of naïve psychology are three concepts that we all use to under-
stand human behavior: desires, beliefs, and actions (Wellman, in press). We apply
these concepts almost every time we think about why someone did something. For
example, why did Jimmy go to Billy’s house? He wanted to play with Billy (a de-
sire), and he expected that Billy would be at home (a belief ), so he went to Billy’s
house (an action). Why did Jenny turn the TV to Channel 5 at 8:00 a.m. on Sat-
urday? She was interested in watching SpongeBob Squarepants (a desire) and she
thought the program was on Channel 5 at 8 in the morning (a belief ), so she selected
that channel at that time (an action).
Three properties of naïve psychological concepts are noteworthy. First, many of
them refer to invisible mental states. No one can see a desire or a belief or other
psychological concepts such as a perception or a memory. We, of course, can see
behaviors related to invisible psychological concepts, such as Jimmy’s ringing Billy’s
doorbell, but we can only infer the underlying mental state, such as Jimmy’s desire
to see Billy. Second, psychological concepts are linked to one another in cause–
effect relations. Jimmy, for example, might get angry if Billy isn’t home because he
went to a different friend’s house, which could later cause Jimmy to be mean to his
younger brother. The third noteworthy property of these naïve psychological con-
cepts is that they develop surprisingly early in life.
Sharp disagreements have arisen between nativists and empiricists regarding
the source of this early psychological understanding. Nativists (e.g., Leslie, 2000)
argue that the early understanding is possible only because children are born with a
basic understanding of human psychology. In contrast, empiricists (e.g., Frye et al.,
1996; Ruffman, Slade, & Crowe, 2002) argue that experiences with other people
and general information-processing capacities are the key sources of the early un-
derstanding of other people. There is evidence to support each view.
Infants’ Naïve Psychology
As we saw in Chapter 5, infants find people interesting, pay careful attention to
them, and learn an impressive amount about them in the first year. Even very young
infants prefer to look at people’s faces rather than at other objects. Infants also imi-
tate people’s facial movements, such as sticking out their tongue, but they do not
imitate the motions of inanimate objects. And it is not just the face that interests
“Wug” “Gilly”
FIGURE 7.1 cause–effect relations
hearing that wugs are well prepared to fight
and gillies prefer to flee helped preschoolers
categorize novel pictures like these as wugs
or gillies (Krascum & andrews, 1998). In
general, understanding cause–effect rela-
tions helps people of all ages learn and
remember.
naïve psychology n a commonsense
level of understanding of other people
and oneself

U N D E R S T A N D I N G W H o o R W H A T n 267
infants; they also prefer to watch human bodies moving instead of other displays
with equal amounts of movement (Bertenthal, 1993).
This early interest in human faces and bodies helps infants learn about people’s
behavior. Imitating other people and forming emotional bonds with them encour-
ages the other people to interact more with the infants, creating additional oppor-
tunities for the infants to acquire psychological understanding.
As noted earlier, many important aspects of psychological understanding emerge
late in the first year and early in the second. One is an understanding of intention,
the desire to act in a certain way. Other key psychological concepts that emerge at
the same time include joint attention, in which two or more people focus inten-
tionally on the same referent; and intersubjectivity, the mutual understanding that
people share during communication (Chapter 4, page 159).
One-year-olds’ understanding of other people already includes an understanding
of their emotions. Consider the following incident:
Michael, 15 months, is struggling with his friend Paul over a toy. Paul starts to cry.
Michael appears concerned and lets go of the toy, so Paul has it. Paul continues cry-
ing. Michael pauses, then gives his own teddy bear to Paul; Paul continues crying.
Michael pauses again, runs to the next room, gets Paul’s security blanket, and gives it
to him. Paul stops crying.
(Hoffman, 1976, pp. 129–130)
Although interpreting anecdotes is always tricky, it seems likely that Michael un-
derstood that giving Paul something that he liked might make him feel better (or
at least stop his crying). Michael’s leaving the room, getting Paul’s security blan-
ket, and bringing it back to him suggests that Michael had the further insight that
Paul’s blanket might be especially useful for soothing his hurt feelings. This inter-
pretation is consistent with a variety of evidence suggesting that 1-year-olds fairly
often offer both physical comfort (hugs, kisses, pats) and comforting comments
(“You be okay”) to unhappy playmates. Presumably, infants’ experience of their own
emotions and the behaviors that accompany them helps them understand the emo-
tions that accompany others’ actions (Harris, 2006).
Development Beyond Infancy
In the toddler and preschool periods, children build on their early-emerging psy-
chological understanding to develop an increasingly sophisticated comprehension
of themselves and other people and to interact with others in increasingly complex
ways. Two areas of especially impressive development are understanding of other
people’s minds and play with peers.
the growth of a theory of mind Infants’ and preschoolers’ naïve psychology, to-
gether with their strong interest in other people, provides the foundation for a
theory of mind, an organized understanding of how mental processes such as in-
tentions, desires, beliefs, perceptions, and emotions influence behavior. Preschool-
ers’ theory of mind includes, for example, knowledge that beliefs often originate in
perceptions, such as seeing an event or hearing someone describe it; that desires can
originate either from physiological states, such as hunger or pain, or from psycho-
logical states, such as wanting to see a friend; and that desires and beliefs produce
actions (S. A. Miller, 2012).
One important component of such a theory of mind—understanding the con-
nection between other people’s desires and their actions—emerges by the end of
the first year. In a study by Phillips, Wellman, and Spelke (2002), 12-month-olds
theory of mind n an organized under-
standing of how mental processes such as
intentions, desires, beliefs, perceptions,
and emotions influence behavior
Indirect ways of breaking bad news are a
specialty of young children and reflect their
understanding that other people’s reactions
might not be the same as their own.
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“Mommy, how much grape juice
would be bad for the rug?”
the FaMILY cIrcUS By Bil Keane

268 n chapter 7 CoNCEpTUAL DEVELopMENT
saw an experimenter look at one of two stuffed kittens and say in a joyful voice,
“Ooh, look at the kitty!” Then a screen descended, and when it was raised 2 seconds
later, the experimenter was holding either the kitty that she had just gushed over or
the other one. The 12-month-olds looked longer when the experimenter was hold-
ing the other kitty, suggesting that they expected the experimenter to want to hold
the kitty that had just excited her so much and were surprised that she was holding
the other one. Eight-month-olds looked for similar amounts of time regardless of
which kitty the experimenter held, suggesting that the understanding that people’s
desires guide their actions develops toward the end of the first year (Phillips et al.,
2002). Consistent with this conclusion, 10-month-olds can use information about
a person’s earlier desires to predict that person’s later desires, but only if the earlier
and later circumstances are virtually identical (Sommerville & Crane, 2009).
The understanding that desires lead to actions is firmly established by age 2
years. Children of this age, for instance, predict that characters in stories will act
in accord with their own desires, even when those desires differ from the child’s
preferences (Gopnik & Slaughter, 1991; Lillard & Flavell, 1992). Thus, if 2-year-
olds who would rather play with trucks than with dolls are told that a character in
a story would rather play with dolls than with trucks, they predict that, given the
choice, the character in the story will choose dolls over trucks.
Although most 2-year-olds understand that desires can influence behavior, they
show little understanding that beliefs are likewise influential. Thus, when 2-year-
olds were told a story in which a character named Sam believed that the only
bananas available were in a cupboard, but they themselves knew that there were
bananas in a refrigerator as well, they were no more likely than by chance to predict
that Sam would act in accord with his own belief and search for bananas only in the
cupboard (Wellman & Woolley, 1990).
By age 3 years, children show some understanding of the relation between be-
liefs and actions. For example, they answer questions such as “Why is Billy look-
ing for his dog?” by referring to beliefs (“He thinks the dog ran away”) as well as
to desires (“He wants it”) (Bartsch & Wellman, 1995). Most 3-year-olds also have
some knowledge of how beliefs originate. They know, for example, that seeing an
event produces beliefs about it, whereas simply being next to someone who can see
the event does not (Pillow, 1988).
At the same time, 3-year-olds’ understanding of the relation between people’s
beliefs and their actions is limited in important ways. These limitations are evident
when children are presented with false-belief problems, in which another person
believes something to be true that the child knows is false. The question is whether
the child thinks that the other person will act in accord with his or her own false
belief or in accord with the child’s correct understanding of the situation. Studying
such situations reveals whether children understand that other people’s actions are
determined by the contents of their own minds rather than by the objective truth
of the situation.
In one false-belief problem, preschoolers are shown a box that ordinarily contains
a type of candy called Smarties and that has a picture of the candy on it (Figure 7.2).
The experimenter then asks what is inside the box. Logically enough, the preschool-
ers say “Smarties.” Next, the experimenter opens the box, revealing that it actually
contains pencils. Most 5-year-olds laugh or smile and admit their surprise. When
asked what another child would say if shown the closed box and asked to guess its
contents, they say the child would answer “Smarties,” just as they had. Not 3-year-
olds! A large majority of them claim they always knew what was in the box, and they
predict that if another child were shown the box, that child would also believe that
false-belief problems n tasks that test
a child’s understanding that other people
will act in accord with their own beliefs
even when the child knows that those
beliefs are incorrect
Why don’t you open the box and see?
Oh, it’s pencils.
What do you think is in the box?
“Smarties!”
Let’s close the box. What do you
think your friend Jenny would say
is in the box if she saw it?
Pencils!
SMARTIES
FIGURE 7.2 testing children’s theory
of mind the Smarties task is frequently
used to study preschoolers’ understanding
of false beliefs. Most 3-year-olds answer the
way the child in this cartoon does, which
suggests a lack of understanding that peo-
ple’s actions are based on their own beliefs,
even when those beliefs deviate from what
the child knows to be true.

U N D E R S T A N D I N G W H o o R W H A T n 269
the box contained pencils (Gopnik & Astington, 1988). The 3-year-
olds’ responses show they have difficulty understanding that other peo-
ple act on their own beliefs, even when those beliefs are false.
This finding is extremely robust. A review of 178 studies of chil-
dren’s understanding of false beliefs showed that similar results
emerged with different forms of the problem, different questions, and
different societies (Wellman, Cross, & Watson, 2001). In one note-
worthy cross-cultural study, false-belief problems were presented to
children attending preschools in Canada, India, Peru, Thailand, and
Samoa (Callaghan et al., 2005). Performance improved greatly be-
tween ages 3 and 5 years in all five societies, from 14% correct for
3-year-olds to 85% correct for 5-year-olds. Especially striking was the
consistency of performance across these very different societies: in no
country did 3-year-olds answer more than 25% of problems correctly,
and in no country did 5-year-olds answer less than 72% correctly.
Although 3-year-olds generally err on false-belief problems when
the problems are presented in the standard way, many children of this
age succeed if the task is presented in a manner that facilitates under-
standing. For example, if an experimenter tells a 3-year-old that the two
of them are going to play a trick on another child by hiding pencils in
a Smarties box and enlists the child’s help in filling the box with pen-
cils, most 3-year-olds correctly predict that the other child will say that
the box contains Smarties (K. Sullivan & Winner, 1993). Presumably,
assuming the role of deceiver by hiding the pencils in the candy box
helps 3-year-olds see the situation from the other child’s perspective.
Nonetheless, it is striking just how difficult 3-year-olds find standard
false-belief problems. To date, no set of conditions has enabled 3-year-olds to solve
standard false-belief questions correctly more often than by chance (Harris, 2006).
Children’s theories of mind continue to develop long beyond this early period,
with at least some of the development dependent on specific experiences. For ex-
ample, 14-year-olds who had experience acting in plays over the course of a school
year showed greater understanding of other people’s thinking at the end of the year
than before their acting experience (T. R. Goldstein & Winner, 2011). In contrast,
peers who received other types of arts education (music or visual arts) for the same
period did not show comparable gains in understanding other people’s thinking.
explaining the development of theory of mind People’s lives clearly would be
very different without a reasonably sophisticated theory of mind. However, the
findings on the improvement in a typical child’s theory of mind between ages 3 and
5 do not tell us what causes the improvement. This question has generated enor-
mous controversy, and currently there is great disagreement about how to answer it.
Investigators who take a nativist position have proposed the existence of a
theory of mind module (TOMM), a hypothesized brain mechanism devoted to
understanding other human beings (Baron-Cohen, 1995; Leslie, 2000). Advocates
of this position argue that among typical children exposed to a typical environment,
the TOMM matures over the first 5 years, producing an increasingly sophisticated
understanding of people’s minds. These investigators cite evidence from brain-
imaging studies showing that certain areas of the brain are consistently active in
representing beliefs across different tasks, and that the areas are different from
those involved in other complex cognitive processes, such as understanding gram-
mar (R. Saxe & Powell, 2006).
Despite leading very different lives, pygmy
children in africa and same-age peers in
industrialized North american and european
societies respond to the false-belief task in
the same way.
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theory of mind module (TOMM) n a
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understanding other human beings

270 n chapter 7 CoNCEpTUAL DEVELopMENT
Further evidence that is often cited to support the idea
of the TOMM comes from children with autism spectrum
disorders. As discussed in Box 7.1, these children have great
difficulty with false-belief problems, as well as with under-
standing people more generally. Consistent with the idea
of a TOMM, one reason for these difficulties in under-
standing the social world appears to be atypical sizes of
certain brain areas that are crucial for understanding people
( Amaral, Schumann, & Nordahl, 2008).
Although most children readily handle
false-belief problems by the age of 5 years,
one group continues to find them very dif-
ficult even when they are teenagers: chil-
dren with autism spectrum disorders (ASD).
As discussed in Chapter 3 (page 95), this
syndrome, which strikes roughly 1 in 100
children in the United States, most of them
male (Centers for Disease Control and Pre-
vention, 2012), involves difficulties in so-
cial interaction, communication, and other
intellectual and emotional functions.
Children with the most serious forms of
ASD (about 1 in 500 children) often engage
in solitary, repetitive behaviors, such as con-
tinually rocking back and forth or endlessly
skipping around a room. They interact mini-
mally with other children and adults, rarely
form close relationships, produce little or no
language, and tend to be more interested in
objects than in people (Willis, 2009). These
problems, among others, have led some re-
searchers to speculate that a failure to under-
stand other people underlies these children’s
limited engagement in the social world.
Recent research supports this hypothesis.
Children with ASD tend to have trouble es-
tablishing joint attention with other people
(Klin et al., 2004). Compared with both typi-
cal children and children with abnormally low
IQs, children with ASD show less concern
when other people appear distressed (Sigman
& Ruskin, 1999) or experience circumstances
that would lead most people to be distressed
(Hobson et al., 2009). These children also
tend to have poor language skills (Tager-
Flusberg & Joseph, 2005), which both re-
flects their lack of attention to other people
and limits their opportunities to learn about
people’s thoughts and feelings through con-
versation. In line with these patterns, chil-
dren with ASD are strikingly befuddled by
false-belief questions (Baron-Cohen, 1991).
For example, fewer than half of 6- to 14-year-
olds with ASD solve false-belief problems that
are easy for typical 4- and 5-year-olds (Peter-
son, Wellman, & Liu, 2005). Children with
ASD have some understanding of how desire
affects behavior, but the ways in which be-
liefs influence behavior largely elude them
(Harris, 2006; Tager-Flusberg, 2007).
Impaired theory-of-mind mechanisms are
not the only source of the difficulty that chil-
dren with ASD encounter in understanding
other people. More general deficits in plan-
ning, adapting to changing situations, and
controlling working memory also contribute
(Ozonoff et al., 2004). Nonetheless, impaired
theory of mind is a source of particular diffi-
culty, especially in understanding situations
in which people’s beliefs differ from reality
(Baron-Cohen, 1993; Tager-Flusberg, 2007).
Fortunately, many problems caused by ASD
can be mitigated by intense and prolonged
early treatment. Dawson and colleagues
(2010) randomly assigned 1- and 2-year-olds
with ASD to receive either Early Start Den-
ver Model (ESDM) treatment or community-
based treatment (the control condition). The
ESDM treatment included roughly 15 hours
per week of sessions with trained therapists,
during which time the therapists and chil-
dren practiced everyday activities, such as
eating and playing, and used operant condi-
tioning techniques to promote desired behav-
iors. These desired behaviors were chosen by
the children’s parents, who also were taught
how to use the approach and were encour-
aged to use it with their child during com-
mon activities such as playing and bathing.
The parents reported using the approach for
an average of 16 hours per week, beyond the
formal ESDM sessions. The effects of ESDM
were compared with those of the community-
based treatment, which included comprehen-
sive diagnostic evaluations, the provision of
resource manuals and reading materials, and
referrals for other types of treatment.
After 2 years of treatment, children who
received the ESDM treatment showed con-
siderably greater gains in IQ score, lan-
guage, and daily living skills than did peers
who received the community-based treat-
ment. This study and others (e.g., Voos et
al., 2012) suggest that early, intensive treat-
ment of ASD can yield large benefits.
BOX 7.1: individual differences
CHILDREN WITH AUTISM SPECTRUM DISORDERS (ASD)
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the child sitting in his mother’s lap shows a distinct lack of interest
in her affection. Such lack of interest in other people is common
among children with autism spectrum disorders and seems related
to their very poor performance on tasks that require an under-
standing of other people’s minds.

U N D E R S T A N D I N G W H o o R W H A T n 271
Theorists who take an empiricist stance suggest a different explanation of the
development of theory of mind, maintaining that psychological understanding
arises from interactions with other people ( Jenkins & Astington, 1996; Ruffman,
Slade, & Crowe, 2002). They cite evidence that on false-belief tasks, preschoolers
who have siblings outperform peers who do not. This finding appears to be stron-
gest when the siblings are older or of the opposite sex, presumably because inter-
acting with people whose interests, desires, and motives are different from their
own broadens children’s understanding of the mind ( Jenkins & Astington, 1996;
S. A. Miller, 2012). From this perspective, the tendency of children with ASD not
to interact much with other people is a major contributor to their difficulty in un-
derstanding others.
A third group of investigators also takes an empiricist stance but emphasizes
the growth of general information-processing skills as essential to understanding
other people’s minds. They cite evidence that children’s understanding of false-be-
lief problems is substantially correlated with their ability to reason about complex
counterfactual statements (German & Nichols, 2003) and with their ability to in-
hibit their own behavioral propensities when necessary (S. M. Carlson, Mandell,
& Williams, 2004; Frye et al., 1996). The ability to reason about counterfactual
statements is important, because false-belief problems require children to predict
what a person would do on the basis of a counterfactual belief. The ability to in-
hibit behavioral propensities is important because false-belief problems also require
children to suppress the assumption that the person would act on the truth of the
situation. Investigators in this camp argue that typical children younger than 4 and
children with ASD lack the information-processing skills needed to understand
others’ minds, whereas typical older children can engage in such processing.
All three explanations have merit. Normal development of brain regions rel-
evant to understanding other people, interactions with other people, and improved
information-processing capacity all contribute to the growth of psychological un-
derstanding during the preschool years. Together, they allow almost all children to
achieve a basic, but useful, theory of mind by age 5.
the growth of play Play refers to activities that are pursued for their own sake,
with no motivation other than the enjoyment they bring. The earliest play activi-
ties, such as banging a spoon on a high-chair tray, tend to be solitary. Over the next
few years, children’s increasing understanding of other people contributes to their
play becoming more social as well as more complex.
One early milestone in the development of play is the emergence,
at around 18 months of age, of pretend play, make-believe activities
in which children create new symbolic relations. When engaged in
pretend play, children act as if they were in a different situation than
their actual one. They often engage in object substitution, ignoring
many of a play object’s characteristics so that they can pretend that it
is something else. Typical examples of object substitution are a child’s
treating a cylindrical wooden block as a bottle and pretending to drink
from it or treating a plastic soap dish as a boat and floating it on the
water while taking a bath.
About a year later, toddlers begin to engage in sociodramatic play,
a kind of pretend play in which they enact miniature dramas with
other children or adults, such as “mother comforting baby” or “doctor
helping sick child” (O’Reilly & Bornstein, 1993). Sociodramatic play
is more complex and more social than object substitution. Consider,
Sociodramatic play, in which children
create miniature dramas based on their
experiences, both reflects children’s under-
standing of the situation and helps them
increase that understanding.
p
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pretend play n make-believe activities
in which children create new symbolic
relations, acting as if they were in a situa-
tion different from their actual one
object substitution n a form of pre-
tense in which an object is used as some-
thing other than itself, for example, using
a broom to represent a horse
sociodramatic play n activities in
which children enact miniature dramas
with other children or adults, such as
“mother comforting baby”

272 n chapter 7 CoNCEpTUAL DEVELopMENT
for example, “tea party” rituals, in which a child and parent “pour tea” for each other
from an imaginary teapot, daintily “sip” it, “eat” imaginary cookies, and comment
on how delicious they are.
Young children’s sociodramatic play is typically more sophisticated when they
are playing with a parent or older sibling who can scaffold the play sequence than
when they are pretending with a peer (Bornstein, 2006; Lillard, 2006). Such scaf-
folding during play provides children with opportunities for learning, in particular
for improving their storytelling skills (Nicolopoulou, 2007). Consider one mother’s
comments as her 2-year-old played with two action figures:
Oh look, Lantern Man is chasing Spider Man. Oh no, he is pushing him down.
Spider Man says, ‘Help, Lantern Man is grabbing me.’ Look, Spider Man is getting
away.
(Kavanaugh & Engel, 1998, p. 88)
Such adult elaboration of implicit storylines in children’s
play provides a useful model for children to follow in later
pretend play with peers or by themselves.
By the elementary school years, play becomes even more
complex and social. It begins to include activities such as
sports and board games that have conventional rules that
participants must follow. The frequent quarrels that arise
among young elementary school students regarding who is
obeying the rules and playing fair attest to the cognitive and
emotional challenges posed by these games (Rubin, Fein, &
Vandenberg, 1983).
Pretend play is often thought of as limited to early child-
hood, but it actually continues far beyond that time. In a
survey of college students, the majority reported that they
had engaged in pretend play at least weekly when they were
10 or 11 years old, and most reported doing so at least monthly when they were 12
or 13 years old (E. D. Smith & Lillard, 2011). Boys and only children tended to
report engaging in pretend play at older ages than girls and children with siblings.
In addition to being fun, pretend play may expand children’s understanding of
the social world. Children who engage in greater amounts of pretend play tend to
show greater understanding of other people’s thinking (Lillard, 2006) and emo-
tions (Youngblade & Dunn, 1995). The type of pretend play in which children
engage also matters: social pretend play is more strongly related to understanding
other people’s thinking than is nonsocial pretend play (Harris, 2000). Preschoolers
also learn from watching others’ pretend play (S. L. Sutherland & Friedman, 2012).
Such evidence has led some experts in the area (e.g., Hirsh-Pasek et al., 2009; Tom-
linson, 2009) to conclude that high levels of pretend play are causally related to in-
creased social understanding. However, a recent comprehensive review of studies of
pretend play (Lillard et al., 2013) found limited evidence for such a causal relation.
Instead, frequent pretend play and high levels of social understanding seem to be
caused by parents who promote both. Some children with high social skills simply
enjoy pretend play and often engage in it. The jury remains out on whether pretend
play is a cause of improved social understanding, but it is clear that such play is not
harmful and that it enriches many children’s lives.
Children’s interest in social play is so strong that they do not let the absence of
playmates prevent them from engaging in it. For such occasions, and even some-
times when playmates are available, they turn to imaginary companions (Box 7.2).
children often enjoy having a parent join
them in sociodramatic play, which tends
to be richer and more informative with a
parent’s participation because the parent
usually provides scaffolding for the play epi-
sode. along with helping to structure the
physical situation, the father in this scene
might be teaching his son strategies for
overcoming adversaries and winning battles.
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U N D E R S T A N D I N G W H o o R W H A T n 273
Knowledge of Living Things
Children are fascinated by living things, especially animals. One sign of their fas-
cination is how often they talk about them. In a study of the first 50 words used by
children, the two terms other than “mama” and “dada” that were used by the greatest
number of children were “dog” and “cat” (and variants such as “doggie” and “kitty”)
(K. Nelson, 1973). “Duck,” “horse,” “bear,” “bird,” and “cow” also were common
early terms. By the time children are 4 or 5 years old, their fascination with living
things translates into an impressive amount of knowledge about them, including
Many children have an imaginary compan-
ion whom they appear to regard as an ac-
tual being. Marjorie Taylor (1999) found that
63% of children whom she interviewed at
age 3 or 4 years and again at age 7 or 8
years reported having imaginary companions
at one or both times. In another study, Taylor
and colleagues (2004) found that as many
6- and 7-year-olds as 3- and 4-year-olds said
that they had imaginary companions—31%
of older children and 28% of younger ones.
Hearing a child talk about an invisible friend
sometimes leads parents to worry about their
child’s sanity, but as these statistics suggest,
children’s creation of such characters is en-
tirely normal.
Most of the imaginary playmates de-
scribed by the children in Taylor’s studies
were ordinary boys and girls who happened
to be invisible. Others were more colorful.
They included Derek, a 91-year-old man
who was said to be only 2 feet tall but able
to hit bears; “The Girl,” a 4-year-old who
always wore pink and was “a beautiful per-
son”; Joshua, a possum who lived in San
Francisco; and Nobby, a 160-year-old busi-
nessman. Other imaginary companions were
modeled after specific people: two exam-
ples were MacKenzie, an imaginary play-
mate who resembled the child’s cousin
MacKenzie, and “Fake Rachel,” who resem-
bled the child’s friend Rachel.
As with real friends, children have a vari-
ety of complaints about their imaginary com-
panions. In a study of 36 preschoolers with
imaginary companions, only one child had
no complaints; the other 35 children griped
that their imaginary companions argued with
them, refused to share,
failed to come when in-
vited, and failed to leave
when no longer welcome
(M. Taylor & Mannering,
2007). In this indepen-
dence from their creator,
the imaginary compan-
ions resemble characters
invented by novelists,
many of whom report
that their characters at
times seem to act inde-
pendently, including ar-
guing with and criticizing
their creator (M. Taylor &
Mannering, 2007).
Contrary to popu-
lar speculation, Taylor
(1999) found that, in
terms of broad characteristics such as per-
sonality, intelligence, and creativity, chil-
dren who invent imaginary playmates are
no different from children who do not.
However, she and other investigators have
identified a few relatively specific differ-
ences between these two groups. Children
who had created imaginary playmates were
more likely (1) to be firstborn or only chil-
dren; (2) to watch relatively little television;
(3) to be verbally skillful; and (4) to have
advanced theories of mind (Carlson et al.,
2003; Taylor & Carlson, 1997; Taylor et al.,
2004). These relations make sense. Being
without siblings may motivate some first-
born and only children to invent friends to
keep them company; not watching much
television frees time for imaginative play;
and being verbally skilled and having an ad-
vanced theory of mind may enable children
to imagine especially interesting compan-
ions and especially interesting adventures.
Companionship, entertainment, and en-
joyment of fantasy are not the only reasons
why children invent imaginary companions.
Children also use them to deflect blame (“I
didn’t do it; Blebbi Ussi did”); to vent anger
(“I hate you, Blebbi Ussi”); and to convey in-
formation that the child is reluctant to state
directly (“Blebbi Ussi is scared of falling into
the potty”). As Taylor (1999) noted, “Imagi-
nary companions love you when you feel re-
jected by others, listen when you need to talk
to someone, and can be trusted not to repeat
what you say” (p. 63). It is no wonder, then,
that so many children invent them.
BOX 7.2: individual differences
IMAGINARY COMPANIONS
although the sight of their child feeding someone who isn’t there
might worry some parents, the creation of imaginary friends is
entirely normal and the majority of children enjoy the company of
such characters at some time in early childhood.
A
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/
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274 n chapter 7 CoNCEpTUAL DEVELopMENT
knowledge of observable biological processes such as growth, and unobservable bio-
logical processes such as inheritance, illness, and healing (S. A. Gelman, 2003).
Coexisting with this relatively advanced knowledge, however, are a variety of
immature beliefs and types of reasoning. For example, children often fail to un-
derstand the difference between artifacts, such as chairs and cars, which are built
by people for specific purposes, and living things, such as monkeys, which are
not created by people for any purpose. Thus, when Kelemen and DiYanni (2005)
asked 6- to 10-year-olds why the first monkey came to exist, the children often
referred to how monkeys serve human purposes, such as “The manager of the
zoo-place wanted some” and “So then we had somebody to climb trees.” Another
weakness in young children’s biological knowledge is their incorrect beliefs about
which things are living and which are not. For instance, most 5-year-olds believe
that plants are not alive, and some believe that the moon and mountains are alive
( Hatano et al., 1993; Inagaki & Hatano, 2002). Such erroneous notions have led
some investigators to conclude that children have only a shallow and fragmented
understanding of living things until they are 7 to 10 years old (Carey, 1999; Slaugh-
ter, Jaakkola, & Carey, 1999). In contrast, other investigators believe that by age
5 years, children understand the essential characteristics of living things and what
separates them from nonliving things but are just confused on a few points ( S. A.
Gelman, 2003). A third view is that young children simultaneously possess both
mature and immature biological understanding (Inagaki & Hatano, 2008). With
this dispute in mind, we will now consider what young children do and do not
know about living things and how they acquire knowledge about them.
Distinguishing Living from Nonliving Things
As noted previously, infants in their first year already are interested in people and
distinguish them from nonliving things (Figure 7.3). Other animals also attract
infants’ interest, though infants act differently toward them than they do toward
people. Nine-month-olds, for example, pay more attention to rabbits than they do
to inanimate objects, but they smile less at rabbits than they do at people (Poulin-
Dubois, 1999; Ricard & Allard, 1993).
These behavioral reactions indicate that infants in their first year distinguish
people from other animals and that they distinguish both from inanimate objects.
However, the reactions do not indicate when children construct a general category
of living things that includes plants as well as animals or when they recognize hu-
mans as a type of animal. It is difficult to assess children’s knowledge of these and
FIGUre 7. 3 Distinguishing people from
nonliving things these photos show a task
used by poulin-Dubois (1999) to study
infants’ reactions when they see people
and inanimate objects (in this case a robot)
engaging in the same action. Both 9- and
12-month-olds show surprise when they
see inanimate objects move on their own,
suggesting that they understand that self-
produced motion is a distinctive character-
istic of people and other animals. Bo
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many other properties of living and nonliving things until the age of 3 or 4 years,
when they can comprehend and answer questions about these categories. By this
age, they clearly know quite a bit about the similarities among all living creatures
and about the differences between living creatures and inanimate objects. This
knowledge of living things is not limited to visible properties such as having legs,
moving, and making distinctive noises. It also extends to biological processes such
as digestion and heredity (S. A. Gelman, 2003). At least through age 5 or 6, how-
ever, many children deny that people are animals (Carey, 1985).
Understanding the life status of plants also presents a challenge to young chil-
dren. On one hand, most preschoolers know that plants, like animals but unlike
inanimate objects, grow (Hickling & Gelman, 1995; Inagaki
& Hatano, 1996), heal themselves (Backscheider, Shatz, &
Gelman, 1993), and die (Springer, Nguyen, & Samaniego,
1996). On the other hand, most preschoolers believe that
plants are not alive; in fact, it is not until age 7 to 9 years
that a clear majority of children realize that plants are liv-
ing things (Hatano et al., 1993). Part of the reason is that
children often equate being alive with being able to move in
adaptive ways that promote survival; plants do move in this
way, but their adaptive movements, such as bending toward
sunlight, occur too slowly to observe under ordinary cir-
cumstances (Opfer & Gelman, 2001). Consistent with this
interpretation, letting 5-year-olds know that plants bend to-
ward sunlight and that their roots grow toward water leads
the children to conclude that plants, like animals, are living
things (Opfer & Siegler, 2004).
More generally, culture and direct experience influence
the age at which children understand that plants are, in fact,
alive. For example, children growing up in rural areas realize that plants are liv-
ing things at younger ages than do children growing up in cities or suburbs ( J. D.
Coley, 2000; N. Ross et al., 2003).
Understanding Biological Processes
Preschoolers understand that biological processes, such as growth, digestion, and
healing, differ from psychological ones (Wellman & Gelman, 1998). For instance,
while 3- and 4-year-olds recognize that desires influence what people do, they also
recognize that some biological processes are independent of one’s desires. Distin-
guishing between biological and psychological processes, for example, leads pre-
schoolers to predict that people who overeat but wish to lose weight will not get
their wish (Inagaki & Hatano, 1993; Schult & Wellman, 1997).
Preschoolers also recognize that properties of living things often serve important
functions for the organism, whereas properties of inanimate objects do not. Thus,
5-year-olds recognize that the green color of plants is crucial for them to make food,
whereas the green color of emeralds has no function for the emerald (Keil, 1992).
The extent of preschoolers’ understanding of biological processes can be understood
more fully by examining their specific ideas about inheritance, growth, and illness.
Inheritance Although 3- and 4-year-olds obviously know nothing about DNA
or the mechanisms of heredity, they do know that physical characteristics tend to
be passed on from parent to offspring. If told, for example, that Mr. and Mrs. Bull
children are interested in living things,
plants as well as animals—especially when
part of the plant tastes good.
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have hearts of an unusual color, they predict that Baby Bull also will have a heart of
that color (Springer & Keil, 1991). Similarly, they predict that a baby mouse will
eventually have hair of the same color as its parents, even if it is presently hairless.
Older preschoolers also know that certain aspects of development are deter-
mined by heredity rather than by environment. For example, 5-year-olds realize
that an animal of one species raised by parents of another species will become an
adult of its own species (S. C. Johnson & Solomon, 1997).
Coexisting with this understanding are numerous misguided beliefs about in-
heritance. Many preschoolers believe that mothers’ desires can play a role in their
children’s inheritance of physical qualities, such as having blue eyes (Weissman &
Kalish, 1999). Many preschoolers also believe that adopted children are at least as
likely to look like their adoptive parents as like their birth parents (G. E. Solomon
et al., 1996). In other situations, preschoolers’ belief in heredity is too strong, lead-
ing them to deny that the environment has any influence. For example, preschool-
ers tend to believe that differences between boys and girls in play preferences are
due totally to heredity (M. G. Taylor, 1993).
Related to this general belief in the importance of heredity is one of the most
basic aspects of children’s biological beliefs—essentialism, the view that living
things have an essence inside them that makes them what they are (S. A. Gelman,
2003). Thus, most preschoolers (as well as most older children and adults) believe
that puppies have a certain “dogness” inside them, kittens have
a certain “catness,” roses have a certain “roseness,” and so on.
This essence is what makes all members of the category similar
to one another and different from members of other categories;
for instance, their inner “dogness” leads to dogs’ barking, chas-
ing cats, and liking to be petted. This essence is viewed as being
inherited from one’s parents and being maintained throughout
the organism’s life. Thinking in terms of such essences seems to
make it difficult, both for children and for many adults, to un-
derstand and accept biological evolution (E. M. Evans, 2008). If
animals inherit an unchanging essence from their parents, how,
they may wonder, would it be possible, say, for mice and whales
to have common ancestors?
Growth, illness, and healing Preschoolers realize that growth, like inheritance, is
a product of internal processes. They recognize, for example, that plants and animals
become bigger and more complex over time because of something going on inside
them (again, preschoolers are not sure what) (Rosengren et al., 1991). Three- and
four-year-olds also recognize that the growth of living things generally proceeds in
only one direction (smaller to larger) at least until old age, whereas inanimate objects
such as balloons can become either smaller or larger at any point in time.
Preschoolers also show a basic understanding of illness. Three-year-olds have
heard of germs and have a general sense of how they operate. They know that eat-
ing food that is contaminated with germs can make a person sick, even if the per-
son is unaware of the germs’ presence (Kalish, 1997). Conversely, they realize that
psychological processes, such as being aware of germs in one’s food, do not cause
illness.
Finally, preschoolers know that plants and animals, unlike inanimate objects,
have internal processes that often allow them to regain prior states or attributes. For
example, 4-year-olds realize that a tomato plant that is scratched can heal itself and
that an animal’s hair can grow back after being cut but that a scratched chair cannot
a fanciful representation of the inner
essence that children believe makes a dog a
dog, a cat a cat, and so on.
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U N D E R S T A N D I N G W H o o R W H A T n 277
heal itself and that a doll’s hair cannot grow back (Backscheider et al., 1993). Pre-
schoolers also recognize the limits of living things’ recuperative processes: they un-
derstand that both illness and old age can cause death, from which no recuperation
is possible (Nguyen & Gelman, 2002).
How Do Children Acquire Biological Knowledge?
As with other aspects of conceptual development, nativists and empiricists have
very different ideas regarding the development of children’s biological understand-
ing. Nativists propose that humans are born with a “biology module” much like
the theory of mind module described earlier in the chapter. This brain structure or
mechanism helps children learn quickly about living things (Atran, 1990, 2002).
Nativists use three main arguments to support the idea that people have a biology
module.
n During earlier periods of our evolution, it was crucial for human survival that
children learn quickly about animals and plants.
n Children throughout the world are fascinated by plants and animals and learn
about them quickly and easily.
n Children throughout the world organize information about plants and animals
in very similar ways (in terms of growth, reproduction, inheritance, illness, and
healing).
Empiricists, in contrast, maintain that children’s biological understanding comes
from their personal observations and from information they receive from parents,
teachers, and the general culture (Callanan, 1990). When mothers read to their
1- and 2-year-olds about animals, for example, many of the mothers’ comments
suggest that animals have intentions and goals, that different members of the
same species have a lot in common, and that animals differ greatly from inanimate
objects (S. A. Gelman et al., 1998). Such teaching is often elicited by children’s
questions: when 3- to 5-year-olds encounter unfamiliar things, they ask a higher
the feelings of awe experienced by many
children (and adults) upon seeing remains of
great animals of the past and present, such
as dinosaurs, elephants, and whales, were
a major reason for the founding of natural
history museums. Despite all the depictions
of monsters and superheroes on television,
in movies, and in video games, these fos-
sils and models inspire the same sense of
wonder in children growing up today.VIS
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278 n chapter 7 CoNCEpTUAL DEVELopMENT
percentage of questions about the functions of things that appear to be man-made
but ask a higher percentage of questions about the biological properties of things
that look like animals or plants (Margett & Witherington, 2011). Such questions
reflect children’s biological knowledge as well as increase it.
Empiricists also note that children’s biological understanding reflects the views
of their culture. For example, 5-year-olds in Japan are more likely than their peers
in the United States and Israel to believe that nonliving things and plants are able
to feel physical sensations, such as pain and cold (Hatano et al., 1993). This ten-
dency of Japanese children echoes the Buddhist tradition, still influential in Japa-
nese society, which views all objects as having certain psychological properties.
As with the parallel arguments regarding the sources of psychological under-
standing, both nature and nurture seem certain to play important roles in the ac-
quisition of biological understanding. Young children are innately fascinated by
animals and learn about them much more quickly than about aspects of their en-
vironment that they find less interesting. At the same time, the particulars of what
children learn obviously are influenced by the information, beliefs, and values con-
veyed to them by their parents and their society. And, as always, nurture responds
to nature, as parents provide informative answers to their children’s many questions
about living things, which in turn reflect the children’s interest in those things.
review:
From early in infancy, children form categories of similar objects. Such categorization helps
them infer the properties of unfamiliar objects within a category. For example, if children
learn that a new object is an animal, they know that it will grow, move, and eat. Children form
new categories, and include new objects within an existing category, on the basis of similari-
ties between the appearance and function of the new object and objects already known to be
category members.
One particularly important category is people. From the first days of life, infants are inter-
ested in other people and spend a great deal of time looking at them. By age 3 years, they
form a simple theory of mind that includes some understanding of the causal relations among
desires, beliefs, and actions. Not until age 4 or 5 years, however, do most children become
able to solve false-belief problems that require them to understand that other people will act
in accord with their own beliefs, even if the child knows that those beliefs are wrong. The
development of understanding of other people’s minds during the preschool period has been
attributed to biological maturation of a theory of mind module, to interactions with other
people, and to the growth of information-processing capabilities that allow children to under-
stand increasingly complex social situations.
Another vital category is living things. During the preschool years, children gain a basic
understanding of the properties of biological entities: growth, heredity, illness, and death. Not
until children go to school, however, do most of them group plants with animals into a single
category of living things. Explanations for children’s relatively rapid acquisition of biological
knowledge include the extensive exposure to biological information provided by families and
the broader culture, children’s own questions that elicit useful information about plants and
animals from other people, and the existence of brain mechanisms that lead children to be
interested in living things and to learn about them quickly and easily.
Understanding Why, Where, When, and How Many
Making sense of our experiences requires accurately representing not only who or
what was involved in an event but also why, where, when, and how often the event
occurred. To grasp the importance of these latter concepts, imagine what life would

U N D E R S T A N D I N G W H Y , W H E R E , W H E N , A N D H o W M A N Y n 279
be like if you lost your understanding of any one of them—your sense of time, for
example. Without a sense of time, you would not know the order in which events
occurred. Did you get dressed and then eat breakfast, or did you eat breakfast and
then get dressed? Your whole impression of your life as a continuous stream of
events would be shattered. Similar problems would arise if you lost your sense of
causality or space or number. Reality would resemble a nightmare in which order
and predictability were suspended and chaos reigned.
As described in the previous section, the categories that children need to answer
the questions “Who?” and “What?” begin forming in infancy, though the under-
standing deepens for many years thereafter. Development of understanding of cau-
sality, space, time, and number follows a similar path. In each case, development
begins in the first year of life, but major improvements continue throughout child-
hood and adolescence.
Causality
The famed eighteenth-century Scottish philosopher David Hume described cau-
sality as “the cement of the universe.” His point was that causal connections unite
discrete events into coherent wholes. Consistent with Hume’s view, from early in
development, children rely heavily on their understanding of causal mechanisms
to infer why physical and psychological events occur. When children take apart
toys to find out how they work, ask how flipping a switch makes a light go on, or
wonder why Mommy is upset, they are trying to understand causal connections.
Because we discussed the development of understanding of psychological causes
earlier in this chapter, we now focus on the development of understanding of
physical causes.
Nativists and empiricists fundamentally disagree about the origins of under-
standing of physical causes. The difficulty of making sense of the world without
some basic causal understanding and the fact that children show some such under-
standing early in infancy have led nativists to propose that infants possess an innate
causal module or core theory that allows them to extract causal relations from the
events they observe (e.g., Leslie, 1986; Spelke, 2003). Empiricists, however, have
proposed that infants’ causal understanding arises from their observations of innu-
merable events in the environment (e.g., L. B. Cohen & Cashon, 2006; T. T. Rogers
& McClelland, 2004). One fact both sides agree on is that children show impres-
sive causal reasoning from infancy onward.
Very Early Causal Reasoning
By 6 months of age, infants perceive causal connections among some physical
events (L. B. Cohen & Cashon, 2006; Leslie, 1986). In a typical experiment dem-
onstrating infants’ ability to perceive such relations, Oakes and Cohen (1995)
presented 6- to 10-month-olds a series of video clips in which a moving object
collided with a stationary object and the stationary object immediately moved in
the way one would expect. Different moving and stationary objects were used in
each clip, but the basic “plot” remained the same. After seeing a few of these video
clips, infants habituated to the collisions. Then the infants were shown a slightly
different clip in which the stationary object started moving shortly before it was
struck. Infants looked at this event for a longer time than they had looked during
the preceding trials, presumably because the new video clip violated their sense that
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280 n chapter 7 CoNCEpTUAL DEVELopMENT
Infants’ and toddlers’ understandings of physical causality influence not only
their expectations about inanimate objects but also their ability to remember and
imitate sequences of actions. When 9- to 11-month-olds are shown actions that are
causally related (e.g., making a rattle by putting a small object inside two cups that
can be pushed together to form a single container), they usually can reproduce the
actions (Figure 7.4 shows a toddler performing this procedure) (Carver & Bauer,
1999). In contrast, when similar but causally unrelated actions are shown, babies do
not reliably reproduce them until age 20 to 22 months (Bauer, 2007).
By the end of their second year, and by some measures even earlier, children
can infer the causal impact of one variable based on indirectly relevant informa-
tion about another. Sobel and Kirkham (2006), for instance, presented 19- and
24-month-olds a box called a “blicket detector” that, the experimenter explained,
played music when a type of object called a blicket was placed on it. Then the ex-
perimenter placed two objects, A and B, on the blicket detector, and the music
played. When the experimenter then placed object A alone on the blicket detector,
the music did not play. Finally, the children were asked to turn on the blicket de-
tector. The 24-month-olds consistently chose object B, indicating that seeing the
ineffectiveness of object A led them to infer that object B was the blicket. In con-
trast, the 19-month-olds chose object A as often as they did object B, suggesting
that they did not draw this inference.
Another illustration of this growing understanding of causality comes from Z.
Chen and Siegler’s (2000) study of 1- and 2-year-olds’ tool use. The toddlers were
presented an attractive toy that was sitting on a table roughly a foot beyond their
FIGURE 7.4 Imitating sequences of
events Understanding the actions they are
imitating helps toddlers perform the actions
in the correct order. In this illustration of
the procedure used by Bauer (1995) to
demonstrate this point, a toddler imitates a
previously observed three-step sequence to
build a rattle. the child (a) picks up a small
block; (b) puts it into the bottom half of
the container; (c) pushes the top half of the
container onto the bottom, thus completing
the rattle; and (d) shakes it.
(a) (b)
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reach. Between the child and the toy were six potential tools
that varied in length and in the type of head at the end of the
shaft (Figure 7.5). To succeed on the task, the toddlers needed
to understand the causal relations that would make one tool
more effective than the others for pulling in the toy. In particu-
lar, they needed to understand that a sufficiently long shaft and
a head at right angles to the shaft were essential.
The 2-year-olds succeeded considerably more often than the
1-year-olds did in obtaining the toy, both in their initial efforts
to get it on their own and after being shown by the experi-
menter how they could use the optimal tool to obtain it. One
reason for the older toddlers’ greater success was that they more
often used a tool to try to get the toy, as opposed to reaching
for it with their hands or seeking their mother’s help. Another
reason was that the older toddlers chose the optimal tool in a greater percentage
of trials in which they used some tool. A third reason was that the older toddlers
more often generalized what they had learned on the first problem to new, superfi-
cially different problems involving tools and toys with different shapes, colors, and
decorations. All these findings indicate that the older toddlers had a deeper un-
derstanding of the causal relations between a tool’s features and its usefulness for
pulling in the toy.
Causal Reasoning During the Preschool Period
Causal reasoning continues to grow in the preschool period. Preschoolers seem
to expect that if a variable causes an effect, it should do so consistently (Schulz
& Sommerville, 2006). When 4-year-olds see a potential cause produce an effect
inconsistently, they infer that some variable that they cannot see must cause the
effect; when the same effect occurs consistently, they do not infer that a hidden
variable was important. For example, if 4-year-olds saw some dogs respond to pet-
ting by eagerly wagging their tails and other dogs respond to petting by growling,
they might infer that some variable other than the petting, such as the dogs’ breed,
caused the effect. But if all the dogs they had ever seen
looked happy when petted, they would not infer that
the dogs’ breed was relevant.
Preschoolers’ emerging understanding that events
must have causes also seems to influence their reac-
tions to magic tricks. Most 3- and 4-year-olds fail to
see the point of such tricks; they grasp that something
strange has happened but do not find the “magic”
humorous or actively try to figure out what caused
the strange outcome (Rosengren & Hickling, 2000).
By age 5, however, children become fascinated with
magic tricks precisely because no obvious causal
mechanism could produce the effect (Box 7.3). Many
want to search the magician’s hat or other apparatus
to see how such a stunt was possible. This increasing
appreciation that even astonishing events must have
causes, along with an increasing understanding of the
mechanisms that connect causes and their effects, re-
flect the growth of causal reasoning.
FIGURE 7.5 toddlers’ problem solving
In the task used by chen and Siegler (2000)
to examine toddlers’ causal reasoning and
problem solving, choosing the right tool for
getting the toy required children to under-
stand the importance of both the length of
the shaft and the angle of the head rela-
tive to the shaft. compared with younger
toddlers, older toddlers had greater under-
standing of these causal relations, which led
them to more often use tools, rather than
just reaching for the toy, and to more often
choose the right tool for the task.
Most 5-year-olds find magic tricks thrilling,
even though they would have been uninter-
ested in them a year or two earlier.
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Lest you conclude that by age 5, children’s
causal reasoning is as advanced as that of
adults, consider the following conversa-
tion between two kindergartners and their
teacher:
Lisa: Do plants wish for baby plants?
Deana: I think only people can make
wishes. But God could put a wish inside
a plant. . . .
Teacher: I always think of people as
having ideas.
Deana: It’s just the same. God puts a little
idea in the plant to tell it what to be.
Lisa: My mother wished for me and I
came when it was my birthday.
(paley, 1981, pp. 79–80)
This is not a conversation that would have
occurred between 10-year-olds and their
teacher. Rather, as noted by Jacqui Woolley,
a psychologist who studies preschoolers’
fantasies, it reflects one of the most charm-
ing aspects of early childhood: preschoolers
and young elementary school children “live
in a world in which fantasy and reality are
more intertwined than they are for adults”
(Woolley, 1997).
Young children’s belief in fantasy and
magic, as well as in normal causes, is evi-
dent in many ways. Most 4- to 6-year-olds
believe that they can influence other people
by wishing them into doing something, such
as buying a particular present for their birth-
day (Vikan & Clausen, 1993). They believe
that effective wishing takes a great deal of
skill, and perhaps magic, but that it can
be done. In related fashion, many believe
that getting in good with Santa Claus can
make their hopes come true. The fantasies
can have a dark side as well, such as when
children fear that monsters might hurt them
(Woolley, 1997).
Research has shown that young children
not only believe in magic; they sometimes
also act on their belief. In one experiment,
preschoolers were told that a certain box
was magical and that if they placed a draw-
ing into it and said magical words, the ob-
ject depicted in the drawing would appear.
Then the experimenter left the children
alone with the box and a number of draw-
ings. The children put drawings of the most
attractive items into the box, said the “mag-
ical words,” and were visibly disappointed
when they opened the box and found only
the drawings (Subbotsky, 1993, 1994).
How can we reconcile preschoolers’ un-
derstanding of physical causes and ef-
fects with their belief in magic, wishing,
and Santa Claus? The key is to recognize
that here, as in many situations, children
simultaneously believe a variety of some-
what contradictory ideas. They may think
that magic or the power of their imagina-
tion can cause things to happen, but they
may not depend on it when doing so could
be embarrassing. In one demonstration of
this limited belief in magic and the power
of the imagination (Woolley & Phelps,
1994), an experimenter showed preschool-
ers an empty box, closed it, and then asked
them to imagine a pencil inside it. The ex-
perimenter next asked the children whether
there was now a pencil in the box. Many
said “yes.” Then an adult came into the
room and said that she needed a pencil to
do her work. Very few of the preschoolers
opened the box or handed it to her. Thus, it
appeared that many children said the box
contained a pencil when no consequences
would follow if they were wrong, but they
did not believe in magic strongly enough
to act in a way that might look foolish to
an adult.
How do children move beyond their be-
lief in magic? One means is learning more
about real causes: the more children know
about the true causes of events, the less
likely they are to explain them in magical
terms (Woolley, 1997). Another influence
is personal experiences that undermine the
child’s magical beliefs, such as hearing
peers pooh-pooh the idea of Santa Claus
or seeing two Santa Clauses on the same
street. Sometimes, however, children sal-
vage their hopes by distinguishing between
flawed manifestations of the magical being
and the magical being itself. They may, for
example, fervently distinguish between the
real Santa Claus and imposters who dress
up to look like him.
Although this world of the imagination is
most striking between ages 3 and 6, aspects
of it remain evident for years thereafter. In
one study that demonstrated the persis-
tence of magical thinking, many 9-year-olds
and some adults reverted to magical expla-
nations when confronted with a trick that
was difficult to explain in physical terms
( Subbotsky, 2005). Moreover, in a recent
poll of a representative sample of the Ameri-
can population, 31% of adults said that they
believe in ghosts (Rasmussen, 2011). These
beliefs in the supernatural cannot be writ-
ten off as simply reflecting a lack of educa-
tion. Subbotsky (2005) found that 0 of 17
college-student participants were willing to
allow someone who was said to be a witch to
cast an evil spell on their lives. Innumerable
other adults indulge superstitions such as
not walking under ladders, avoiding cracks
in sidewalks, and knocking on wood. Ap-
parently, we never entirely outgrow magical
thinking.
BOX 7.3: a closer look
MAGICAL THINKING AND FANTASY
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the FaMILY cIrcUS By Bil Keane

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Space
The nativist/empiricist debate has been vigorous with regard to spatial thinking.
Nativists argue that children possess an innate module that is specialized for rep-
resenting and learning about space and that processes spatial information sepa-
rately from other types of information (Hermer & Spelke, 1996; Hespos & Spelke,
2004). Empiricists argue that children acquire spatial representations through the
same types of learning mechanisms and experiences that produce cognitive growth
in general, that children adaptively combine spatial and nonspatial information
to reach their goals, and that language and other cultural tools such as puzzles
shape spatial development (Gentner & Boroditsky, 2001; S. C. Levine et al., 2012;
Newcombe & Huttenlocher, 2006).
Nativists and empiricists agree on some issues. One is that from early in infancy,
children show impressive understanding of some spatial concepts, such as above,
below, left of, and right of (Casasola, 2008; P. C. Quinn, 2005). Another common
conclusion is that self-produced movement around the environment stimulates
processing of spatial information. A third shared belief is that certain parts of the
brain are specialized for coding particular types of spatial information; for example,
development of the hippocampus appears to produce improvements in place learn-
ing (Sluzenski, Newcombe, & Satlow, 2004; Sutton, Joanisse, & Newcombe, 2010).
A fourth common conclusion is that geometric information—information about
lengths, angles, and directions—is extremely important in spatial processing. When
toddlers and preschoolers are given clues to an object’s location, they often weigh
such geometric information more strongly than seemingly simpler nongeometric
cues, such as the object’s being in front of the one blue wall in the room (Hermer
& Spelke, 1996; Newcombe & Ratliff, 2007).
Effective spatial thinking requires coding space relative to oneself and rela-
tive to the external environment. Next we consider each of these types of spatial
coding.
Representing Space Relative to Oneself
From early in infancy, children code the locations of objects in relation to their own
bodies. As noted in Chapter 5, when young infants are presented with two objects,
they tend to reach for the closer one (van Wermeskerken et al., 2012). This shows
that they recognize which object is closer and that they know the direction of that
object relative to themselves.
Over the ensuing months, infants’ representations of spatial locations become
increasingly durable, enabling them to find objects they observed being hidden
some seconds earlier. As discussed in Chapter 4, most 7-month-olds reach to the
correct location for objects that were hidden 2 seconds earlier under one of two
identical opaque covers, but not for objects hidden 4 seconds earlier, whereas most
12-month-olds accurately reach for objects hidden 10 seconds earlier (A. Diamond,
1985). In part, these increasingly enduring object representations reflect brain mat-
uration, particularly of the dorsolateral prefrontal cortex, an area in the frontal lobe
that is involved in the formation and maintenance of plans and in the integration
of new and previously learned information (A. Diamond & Goldman-Rakic, 1989;
J. K. Nelson, 2005). However, the improved object representations reflect learn-
ing as well: infants who are provided a learning experience with a hidden object in
one situation show improved location of hidden objects in other situations (S. P.
Johnson, Amso, & Slemmer, 2003).

284 n chapter 7 CoNCEpTUAL DEVELopMENT
Note that the preceding examples of infants’ ability to code space involve infants
remaining in a single location and coding locations relative to their bodies. Piaget
(1954/1971) proposed that this is the one kind of spatial coding that infants can do.
The reason, according to his theory, is that during the sensorimotor period, infants
can form only egocentric spatial representations, in which the locations of objects
are coded relative to the infants’ position at the time of the coding. As evidence,
Piaget reported experiments showing that if infants repeatedly found a toy located
to their right, they would continue to turn right to find it, even if they were reposi-
tioned so that the object was now on their left. Subsequent investigators replicated
this finding (e.g., L. P. Acredolo, 1978; Bremner, 1978).
Egocentric spatial representation during infancy is not absolute, however. If toys
are hidden adjacent to a distinctive landmark, such as a tower, infants usually find
the toy despite changes in their own position (Lew, 2011). Still, the question re-
mains: How do young children become able to find objects when their own posi-
tion has changed and when no landmarks are available to guide their search?
A major factor in helping infants acquire a sense of space independent of their
own location appears to be self-locomotion. Infants who crawl or have had experi-
ence propelling themselves in walkers more often remember the locations of objects
on the object permanence task (page 165) than do infants of the same age without
such locomotor experience (Bertenthal, Campos, & Kermoian, 1994; Campos et al.,
2000). Similarly, compared with infants who have not yet moved across rooms on
their own, those infants who have done so show an earlier understanding of depth
and drop-offs on the surfaces they travel; this is evidenced by acceleration in their
heart rate as they approach the visual cliff in the procedure described on page 196.
The reasons why self-locomotion enhances infants’ representation of space
should be familiar to anyone who has both driven a car and been a passenger in one.
Just as driving requires continuous updating of information about the surround-
ings, so does crawling or walking. In contrast, just as being a passenger in a car does
not require such continuous updating of one’s location, neither does being carried.
As would be expected from this analysis, self-locomotion also enhances older
children’s spatial coding. Striking evidence for this conclusion emerged from a
study in which kindergarteners were tested in the kitchens of their own homes
(Rieser, Garing, & Young, 1994). Some kindergartners were asked to stand in
place, imagine themselves walking from their seat in the classroom to the teacher’s
chair, and turning around to face the class. Then they were asked to point from this
imagined position in the classroom to the locations of various objects within it—
the fishbowl, the alphabet chart, the coatroom door, and so on. Under these condi-
tions, the 5-year-olds’ pointing was inaccurate. Other kindergartners went through
the same procedure, except that they were instructed to actually walk through their
kitchen and turn around as they imagined themselves walking to the teacher’s chair
and then turning to face the class. Under these conditions, the children’s pointing
to the imagined objects in their imagined classroom was far more accurate. This
result, like those described above with infants, highlights the interconnectedness
of the system that produces self-generated motion and the system that produces
mental representations of space (Adolph & Berger, 2006).
Another type of experience that contributes to spatial development beyond infancy
is the assembling of puzzles. Children who played with puzzles more often between
their 1st and 4th birthdays than their peers did were found to be more successful as
4½-year-olds on the spatial transformation task shown in Figure 7.6 (Levine et al.,
2012). The relation between puzzle play and subsequent spatial reasoning occurred
irrespective of parents’ education, income, and use of spatial terms while interacting
egocentric spatial representations n
coding of spatial locations relative to
one’s own body, without regard to the
surroundings
FIGURE 7.6 Measuring early spatial
reasoning these are the shapes used by
Levine and colleagues (2012) to examine
the effects of playing with puzzles on pre-
schoolers’ spatial skills. the task was to
identify which of the shapes in the top
panel could be constructed from the pair of
shapes in the bottom panel.
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with their children. This relation between puzzle play and spatial reasoning makes
sense. Assembling puzzles requires identifying appropriate pieces for specific loca-
tions and physically rotating them into the proper orientation; mentally rotating
pieces to identify plausible candidates for filling empty locations allows more efficient
puzzle solving than would otherwise be possible. Such practice in mental rotation
seems likely to build spatial-reasoning skills that can be used in future situations.
Development of Spatial Concepts in Blind and Visually
Impaired People
People often equate spatial thinking with vision, assuming that we can think spa-
tially only about layouts that we have seen. Even in infancy, however, spatial thought
can be based on senses other than vision. Thus, when 3-month-olds are brought
into a totally dark room in which nothing can be seen, they use sounds emitted by
nearby objects to identify the objects’ spatial locations and reach for them (Keen &
Berthier, 2004).
Although infants can use their auditory sense, among other senses, to form spa-
tial representations, visual experience during infancy does play an important role in
spatial development. Evidence for this conclusion comes from cases in which sur-
gery restored sight to people who were born either blind (S. Carlson, Hyvärinen,
& Raninen, 1986) or with severely impaired vision due to cataracts that prevented
patterned stimulation from reaching the retina (Le Grand et al., 2001, 2003). The
surgery was performed early—on average at 4 months of age—and those who un-
derwent it subsequently had between 9 and 21 years of postsurgical visual experience
before being tested. Despite their extensive visual experience after the corrective sur-
gery, most of these people could not use visual information to represent space as well
as other people can; problems remained, especially with representations of faces, even
20 years after the surgery (and thus after 20 years of visual experience). The lack of vi-
sual experience in the few months of infancy limited subsequent visual development.
These findings do not mean that children who are born blind cannot represent
space. They actually tend to have a surprisingly good spatial sense. On tasks involv-
ing the representation of very small spaces, such as being guided in drawing two
sides of a triangle on a piece of paper and then being asked to complete the triangle
by drawing the third side themselves, children who are born blind perform as well
as sighted children who are blindfolded (Thinus-Blanc & Gaunet, 1997). On tasks
involving representation of large spaces, such as those formed by exploring unfamil-
iar rooms, the spatial representations of people born blind also are surprisingly good,
about as good as those formed by sighted people who were blindfolded during the
exploration period. Thus, although some spatial skills seem to require early visual
experience, many blind people develop impressive senses of space without ever see-
ing the world.
Representing Space Relative to the External Environment
As we have noted, infants as young as 6 months can use landmarks to code the lo-
cation of objects they observe being hidden (Lew, 2011). However, for such young
infants to use a landmark successfully, it must be the only obvious landmark in the
environment and must be located right next to the hidden object.
With development, infants become increasingly able to choose among alter-
native potential landmarks. When 12-month-olds are presented a single yellow
cushion, a single green cushion, and a large number of blue cushions, they have
little trouble finding an object hidden under either the yellow or the green cushion
Blind adolescents and adults, even those
blind from birth, tend to have a quite accu-
rate sense of space, which helps them move
around the environment skillfully.
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286 n chapter 7 CoNCEpTUAL DEVELopMENT
(Bushnell et al., 1995). At 22 months, but not at 16 months, the presence of a land-
mark improves children’s ability to locate an object that is not hidden adjacent to
the landmark (Newcombe et al., 1998). By age 5 years, children can also represent
an object’s position in relation to multiple landmarks, such as when it is midway
between a tree and a street lamp (Newcombe & Huttenlocher, 2006).
Children, like adults, have more difficulty forming a spatial representation when
they are moving around in an environment without distinctive landmarks or when
the only landmarks are far from the target location. To understand the challenge of
such tasks, imagine walking in an a forest without cleared paths and not being able
to remember exactly how you arrived at your current location. How easily could you
find your way back to your starting point?
Even toddlers show the required navigational ability to some degree—good
enough to lead them in the right general direction (Loomis et al., 1993). In one
experiment, 1- and 2-year-olds first saw a small toy hidden in a long, rectangular
sandbox and then saw a curtain descend around the sandbox, thus hiding the toy.
The toddlers then walked to a different location, after which they were asked to
find the toy. Despite no landmarks being present, the toddlers kept track of the
hidden toy’s location well enough to show better than chance accuracy in their
searches (Newcombe et al., 1998).
However, forming relatively precise coding of locations in the absence of
straightforward landmarks continues to be difficult for people well beyond 2 years
of age (Bremner, Knowles, & Andreasen, 1994). Six- and seven-year-olds are not
very good at it (Overman et al., 1996), and adults vary tremendously in their abili-
ties to perform this type of navigation. For example, when adults are asked to walk
around the perimeter of an unfamiliar college campus and then to walk straight
back to the starting point, some are quite accurate, but many choose routes that
take them nowhere near the original location (Cornell et al., 1996).
The degree to which people develop spatial skills is strongly influenced by the
importance of such skills in their culture. To demonstrate this point, Kearins (1981)
compared the spatial abilities of seminomadic aboriginal
children growing up in the Australian desert with those
of White peers growing up in Australian cities. Spa-
tial ability is essential within aboriginal culture, because
much of life within this culture consists of long treks
between distant water holes. Needless to say, the ab-
original people cannot rely on road signs; they must rely
on their sense of space to get to the water. Consistent
with the importance of spatial skills within their every-
day lives, aboriginal children are superior to their city-
dwelling peers in memory for spatial location, even in
board games, a context that is more familiar to the urban
children (Kearins, 1981). Thus, consistent with the gen-
eral importance of the sociocultural context, how people
make use of spatial thinking in their everyday activities
greatly influences their quality of spatial thinking.
Time
“What then is time? I know well enough what it is, provided nobody asks me; but if
I am asked and try to explain, I am baffled.”
—Saint Augustine, 398 C.E. (1963)
Spatial skills tend to be especially well
developed in cultures in which they are
crucial for survival.
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As this quotation suggests, even the deepest thinkers, from Saint Augustine who
wrote in the fourth century to Albert Einstein who wrote in the twentieth, have
been mystified by the nature of time. Yet even infants in their first half-year have a
rudimentary sense of time, including perception of both the order and the duration
of events (W. J. Friedman, 2008).
Experiencing Time
Probably the most basic sense of time involves knowledge of temporal order, that
is, knowing what happened first, what happened next, and so on. Not surprisingly,
given how mystifying life would be without such a basic sense of time, infants rep-
resent an understanding of the order in which events occur from as early as the
capability can be effectively measured. In one study, 3-month-olds were presented
a series of interesting photos, first on their left, then on their right, then on their
left, and so on. Within 20 seconds, they began to look to the side where each new
photo was to appear even before the photo was presented (Adler et al., 2008; Haith,
Wentworth, & Canfield, 1993). This looking pattern indicated that 3-month-olds
detected the repetitive sequence of events over time and used the information to
form expectations of where the next photo would appear. The same conclusion has
arisen using other experimental methods; for example, 4-month-olds who were
habituated to three objects falling in a constant order dishabituated when the order
changed (Lewkowicz, 2004).
Infants also have an approximate sense of the durations of events. In one study,
4-month-olds saw periods of light and darkness alternate every 5 seconds for eight
cycles, at which point the pattern was broken by the light’s failing to appear. Within
half a second of the break, infants’ heart rates decelerated, a change that is char-
acteristic of increased attention. In this case, the heart-rate deceleration suggested
that the infants had a rough sense of the 5-second interval, expected the light to go
on at the end of the interval, and increased their attention when it did not appear
(Colombo & Richman, 2002).
Infants also can discriminate between longer and shorter durations. The ratio of
the durations, rather than differences in their absolute length, is critical for these
discriminations (Brannon, Suanda, & Libertus, 2007). For instance, 6-month-olds
discriminate between two durations when their ratio is 2:1 (1 second versus 0.5
seconds or 3 seconds versus 1.5 seconds), but not when the ratio is 1.5:1 (1.5 sec-
onds versus 1 second or 4.5 seconds versus 3 seconds). Over the course of the first
year, the precision of these discriminations increases. Thus, 10-month-olds, unlike
6-month-olds, discriminate when the ratio of the durations is 1.5:1 (though not
when it is 1.33:1).
What about longer periods—periods of weeks, months, or years? It is unknown
whether infants have a sense of such long periods, but preschoolers do possess some
knowledge regarding them. For example, when asked which of two past events oc-
curred more recently, most 4-year-olds knew that a specific event that happened
a week before the experiment (Valentine’s Day) happened more recently than an
event that happened 7 weeks earlier (Christmas) (W. J. Friedman, 1991). However,
preschoolers correctly answer such questions only when the more recent event is
quite close in time and much closer than the less recent one. Ability to distinguish
more precisely among the timing of past events develops slowly during middle
childhood (W. J. Friedman, 2003). For example, when children who had been pre-
sented a distinctive classroom experience were asked 3 months later to recall the
month in which the experience occurred, the percentage of correct recall increased

288 n chapter 7 CoNCEpTUAL DEVELopMENT
from 20% among 5-year-olds to 46% among 7-year-olds to 64% among 9-year-
olds ( W. J. Friedman & Lyon, 2005).
Understanding of the timing of future events also increases during this age range
(W. J. Friedman, 2000, 2003). Preschoolers often confuse past and future. For ex-
ample, 5-year-olds predict a week after Valentine’s Day that the next Valentine’s
Day will come sooner than the next Halloween or Christmas; they also predict that
their next lunch is the same amount of time in the future regardless of whether
they are tested just before lunch or just after it. Six-year-olds, in contrast, generally
predict correctly in both cases. The improvement in children’s sense of future time
between the ages of 5 and 6 years is probably influenced by 5- and 6-year-olds’ ex-
perience in kindergarten classrooms, where the cycle of seasons, holidays, and daily
routines is emphasized.
Children, like adults, are subject to certain illusions about time, in part because
of the role attention plays in time perception. When 8-year-olds’ attention is fo-
cused on the passage of time (for example, when they expect a prize at the end of
a 2-minute interval), they perceive the duration as longer than the same interval
when they are not anticipating a prize. Conversely, when they have little to do they
perceive the duration as longer than when they are very busy (Zakay, 1992, 1993).
Thus, the saying “A watched pot never boils” has psychological merit.
Reasoning About Time
During middle childhood, children become increasingly proficient at reasoning
about time. In particular, they become able to infer that if two events started at the
same time, but one event ended later than the other, then the event that ended later
lasted longer.
Children as young as 5 years can sometimes make such logical inferences about
time, but only in simple, straightforward situations. For instance, when told that
two dolls fell asleep at the same time and that one doll awoke before the other,
5-year-olds reason correctly that the doll that awoke later also slept longer (Levin,
1982). However, when 5-year-olds see two toy trains travel in the same direction
on parallel tracks, and one train stops farther down the track, they usually say that
the train that stopped farther down the track traveled for a longer time, regardless
of when the trains started and stopped moving (C. Acredolo & Schmid, 1981).
The problem is that the 5-year-olds’ attention is captured by the one train being
farther down the track, which leads them to focus on the spatial positions of the
trains rather than on their relative starting and stopping times. If this observation
reminds you of Piaget’s idea of centration (pages 139–141), there is good reason:
Piaget’s (1969) observations of performance on this task were part of what led him
to conclude that children in the preoperational stage often center on a single di-
mension and ignore other, more relevant ones.
Number
Like causality, space, and time, number is a central dimension of human experi-
ence. It is hard to imagine how the world would appear if we did not have at least a
crude sense of number—we would not know how many fingers or family members
we have, for example. Unsurprisingly, the nativist/empiricist debate has extended to
the concept of number. Nativists argue that children are born with a core concept of
number that includes special mechanisms for representing and learning about the
relative numbers of objects in sets, counting, and simple addition and subtraction

U N D E R S T A N D I N G W H Y , W H E R E , W H E N , A N D H o W M A N Y n 289
(Wynn, 2000). As evidence, they note that specific brain areas, particularly the
intraparietal sulcus, are heavily involved in representing numerical magnitudes
(Ansari, 2008; Nieder & Dehaene, 2009) and that specific neurons respond most
strongly when particular numbers of objects (e.g., 5 objects) are displayed (Nieder,
2012). In contrast, empiricists argue that children learn about numbers through the
same types of experiences and learning mechanisms that help them acquire other
concepts and that infants’ numerical competence is not as great as nativists claim
(Clearfield, 2006; Mix, Huttenlocher, & Levine, 2002). They also note the exis-
tence of large differences in numerical understanding among children of different
cultures and document the contributions of instruction, language, and cultural val-
ues to these differences (Geary, 2006; K. F. Miller et al., 1995). In this section, we
review current evidence regarding numerical development as well as nativist and
empiricist perspectives on the evidence.
Numerical Equality
Perhaps the most basic understanding of numbers involves numerical equality, the
idea that all sets of N objects have something in common. When children recog-
nize, for example, that two dogs, two cups, two balls, and two shoes share the prop-
erty of “twoness,” they have a rudimentary understanding of numerical equality.
Infants as young as 5 months old appear to have some sense of numerical equality,
at least as it applies to sets of one, two, or three objects. The evidence for this conclu-
sion comes from studies using the familiar habituation paradigm. In these studies,
young infants are shown a sequence of pictures, with each picture having the same
number of objects but differing in other ways. For example, infants might be shown
three stars arranged vertically, then three circles arranged horizontally, then three
diamonds arranged diagonally, and so on. After the infants habituate to the pictures
of three objects, they are shown a picture with a different number of objects (such as
two squares). These studies indicate that 5-month-olds show renewed interest when
the number of objects changes (van Loosbroek & Smitsman, 1990).
This tendency is weak—infants’ discriminations are often based on the objects’
relative area or perimeter rather than on their number, when both vary (Clearfield
& Mix, 1999; Feigenson, Carey, & Spelke, 2002). However, infants also discrimi-
nate among small numbers of events, which do not have perimeters or areas, in-
dicating that they have a sense of number independent of spatial concepts. In one
demonstration of this numerical understanding, Wynn (1995) showed 6-month-
olds a puppet that repeatedly jumped twice. After the infants habituated to this
pattern, they were shown the puppet jumping either once or three times. The in-
fants’ looking time increased when the number of jumps changed, suggesting that
they discriminated between two jumps and one or three.
As with discriminations among temporal durations, infants’ discriminations be-
tween numerical sets depend in large part on the ratio of the number of entities in
them. For example, as with temporal durations, 6-month-olds discriminate between
sets with 2:1 ratios (e.g., 16 versus 8 dots or sounds) but not between sets with ratios
of 1.5:1 (e.g., 12 versus 8 dots or sounds) (Brannon, 2002; Lipton & Spelke, 2003).
Also similar to discriminations between temporal durations, numerical-set discrimi-
nations become more precise with age: 6-month-olds do not discriminate between
ratios of 1.5:1 objects, but 9-month-olds do ( J. N. Wood & Spelke, 2005). However,
the absolute number of objects also matters: on some tasks, 9- and 11-month-old
infants discriminate between one and two objects but not between two and four or
three and six objects (Feigenson, Carey, & Hauser, 2002).
numerical equality n the realization
that all sets of N objects have something
in common

290 n chapter 7 CoNCEpTUAL DEVELopMENT
Infants’ Arithmetic
Some experts on early understanding of number have concluded that infants also
have a basic understanding of arithmetic (R. Gelman & Williams, 1998; Wynn,
1992). The type of evidence on which they base their conclusion is illustrated in
Figure 7.7. A 5-month-old sees a doll on a stage. A screen comes up, hiding the
doll from the infant’s sight. Next, the infant sees a hand place a second doll be-
hind the screen and then sees the hand emerge from behind the screen without the
doll, thus seeming to have left the second doll with the first one. Finally, the screen
drops down, revealing either one or two dolls. Most 5-month-olds look longer
when there is only one doll, suggesting that they expected that 1 1 1 should equal
2 and that they were surprised when they saw only a single object. Similar results
are seen with subtraction: 5-month-olds look longer when the apparent removal
of one of two objects results in two objects being present than when the removal
results in one object being there (Wynn, 1992).
But do these findings show that infants understand arithmetic? The claim that
they do has evoked a great deal of argument. One reason for the controversy is that
efforts to replicate the original result have had mixed success. Some studies have
replicated it (T. J. Simon, Hespos, & Rochat, 1995), others have not (Wakeley, Ri-
vera, & Langer, 2000). A more general reason for the controversy is that infants
show the precise understanding required by arithmetic only in situations in which
the total number of objects is three or fewer. Children do not show similar, precise
understanding of the effects of adding two objects to two other objects until they
are much older—3 to 5 years old ( J. Huttenlocher, Jordan, & Levine, 1994; Star-
key, 1992).
The fact that much of infants’ numerical competence is limited to sets of three
or fewer objects has led a second group of experts (Clearfield & Mix, 1999; L. B.
Cohen & Marks, 2002; T. J. Simon, 1997) to conclude that infants’ responses on
these tests of arithmetic are based not on understanding of arithmetic but instead
on perception. For example, Haith and Benson (1998) proposed that infants rely on
subitizing, a perceptual process by which adults and children can look at one, two,
or three objects and almost immediately form a mental image of how many objects
1. Object placed in case
Sequence of events: 1 + 1 = 1 or 2
2. Screen comes up 3. Second object added 4. Hand leaves empty
5. Screen drops…
Then either: (a) Possible Outcome Or (b) Impossible Outcome
6. revealing 2 objects 5.* Screen drops… 6.* revealing 1 object
FIGURE 7.7 Infants’ under-
standing of addition On the task
used by Wynn (1992) to examine
whether infants have a rudimentary
grasp of addition, 5-month-olds saw
(1) a single doll placed on a stage,
(2) a screen raised to hide the doll,
(3) a hand with a doll in it move
toward and then behind the screen,
and (4) the hand return empty after
having been behind the screen.
then the screen dropped, revealing
either the possible event of two dolls
on the stage (5 and 6) or the seem-
ingly impossible event of one doll
on the stage (5* and 6*). Infants
younger than 6 months looked for a
longer time at the seemingly impos-
sible event, suggesting their surprise
subitizing n a perceptual process by
which adults and children can look at a
few objects and almost immediately know
how many objects are present

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there are. According to this interpretation, infants form an image of the object or
objects that are initially presented and of the objects that seem to be added to, or
subtracted from, them; if the objects that the infants see at the end of the proce-
dure appear different from the image they originally formed, they look for a lon-
ger time. Consistent with this interpretation, when 5-month-olds are tested under
conditions that increase the difficulty of forming a mental image (e.g., when they
see a hand place one object and then a second object behind the raised screen but,
in contrast to the usual procedure, do not see either object’s position until the end),
the infants do not show surprise when 1 1 1 5 1 (Uller et al., 1999). Thus, under
some circumstances, infants show arithmetic competence with small sets of objects,
but their competence may stem from an ability to form mental images rather than
from an understanding of arithmetic.
Counting
By age 3 years, most children acquire the ability to count, allowing them to pre-
cisely establish the number of objects in sets larger than three when the objects are
visible. The majority of 3-year-olds can count up to 10 objects correctly. In addi-
tion to learning counting procedures, preschoolers also acquire understanding of
the principles underlying counting. In particular, they come to understand the fol-
lowing five counting principles (R. Gelman & Gallistel, 1978):
1. One–one correspondence: Each object must be labeled by a single number word.
2. Stable order: The numbers should always be recited in the same order.
3. Cardinality: The number of objects in the set corresponds to the last number
stated.
4. Order irrelevance: Objects can be counted left to right, right to left, or in any
other order.
5. Abstraction: Any set of discrete objects or events can be counted.
Much of the evidence that preschoolers understand these principles comes from
their judgments when observing two types of counting procedures: incorrect counts
and unusual but correct counts. When 4- or 5-year-olds see a puppet counting in
a way that violates the one–one correspondence principle—for example, by label-
ing a single object with two number words (Figure 7.8a)—they consistently say that
the counting is incorrect (Frye et al., 1989; R. Gelman, Meck, & Merkin, 1986). In
contrast, when they see the puppet count in ways that are unusual but that do not
violate any principle—for example, by starting in the middle of a row but counting
all the objects (Figure 7.8b)—they judge the counting to be correct, even though
they say that they would not count that way themselves. The pre-
schoolers’ realization that procedures that they themselves would
not use are nonetheless correct shows that they understand the
principles that distinguish correct from incorrect counting.
Although children all over the world learn number words, the
rate at which they do so is affected by the specifics of the number
system used in their culture. As Kevin Miller and his colleagues
(1995) note, for example, most 5-year-olds in China can count to
100 or more, whereas most 5-year-olds in the United States cannot
count nearly as high. Part of the reason for this difference in count-
ing proficiency seems to be the greater regularity of the Chinese
number system, particularly with respect to numbers in the teens. In
both Chinese and English, the words for numbers greater than 20
(a) Incorrect counting

Number stated:
Pointing:
Objects:
1
(b) Unusual but correct counting

Number stated:
Pointing:
Objects:
2 3 4
3 1 2
FIGURE 7.8 counting procedures
counting procedures similar to those used
by Frye and colleagues (1989) and Gelman,
Meck, and Merkin (1986): (a) an incorrect
counting procedure; (b) an unusual but cor-
rect procedure.

292 n chapter 7 CoNCEpTUAL DEVELopMENT
follow a regular rule: decade name first, digit name second (e.g.,
twenty-one, twenty-two, and so forth). In Chinese, the words for
numbers between 11 and 19 follow the same rule (equivalent to
ten-one, ten-two, and so on). In English, however, no simple rule
indicates the numbers between 11 and 19; each term has to be
learned separately.
Figure 7.9 charts the apparent impact of this cultural differ-
ence in number systems. Three-year-olds in the United States
and China are comparable in their ability to recite the numbers
1 through 10, which do not follow any obvious rule either in
the English or the Chinese language. However, Chinese 4-year-
olds quickly learn the numbers in the teens and succeeding de-
cades, whereas their U.S. peers experience prolonged difficulty
with the teens. The difference in language is not the only reason
that the counting skill of U.S. children lags behind that of chil-
dren in China. Chinese culture places a much greater emphasis
on mathematical skill than U.S. culture does, and Chinese pre-
schoolers are consequently more advanced than their U.S. peers
in numerical skills generally, including arithmetic and number-line estimation
(Siegler & Mu, 2008). Still, the greater simplicity of the Chinese system for nam-
ing numbers in the teens seems to be one contributor to Chinese children’s greater
counting proficiency.
Relations Among Understanding of Space, Time,
and Number
Piaget (1952) hypothesized that infants possess only a general, undifferentiated
concept of magnitude, and lack specific concepts of space, number, and time. That
is, he thought that infants have a concept of “bigness” but do not distinguish among
larger size, greater number, or longer time. Subsequent research has shown that in-
fants actually do distinguish among size, number, and time. For example, after ha-
bituating to different displays with the same number of objects, infants dishabituate
when the number of objects changes, even though the space occupied by the new
objects and the time for which they are displayed is the same as previously (F. Xu
& Arriaga, 2007; F. Xu & Spelke, 2000).
However, the fact that infants possess specific concepts of space, time, and num-
ber does not mean that they lack the type of undifferentiated magnitude concept
that Piaget suggested. Indeed, Lourenco and Longo (2010) found that 9-month-
olds have a general sense of magnitude that extends to space, number, and time.
The infants in their study were initially habituated to the type of display shown
at the top of Figure 7.10, in which a particular decoration (e.g., black with white
stripes) consistently accompanied the larger of two stimuli on one of the three di-
mensions (e.g., size). Then the infants were presented displays in which the link
between decoration and relative magnitude on a different dimension either was
maintained or changed. For example, infants who had habituated to a link be-
tween black with white stripes and larger size might now see that decoration ac-
companying either the more numerous set (bottom left in Figure 7.10) or the less
numerous one (bottom right in Figure 7.10). Lourenco and Longo found that the
infants dishabituated when the decoration that had accompanied the larger stimu-
lus now accompanied the one that was smaller on another dimension, but not when
it continued to accompany the larger one. Similar results were obtained regardless
5
Age in years
43
0
20
40
60
80
100
H
ig
h
es
t
n
u
m
b
er
c
ou
n
te
d
China
United States
FIGURE 7.9 counting level although
3-year-olds in china and the United States
can count to about the same point, 4- and
5-year-olds in china can count much higher
than their U.S. peers. One reason for the
faster development of chinese children’s
counting ability appears to be that the chi-
nese words for numbers in the teens follow
a consistent, easily learned pattern, whereas
the english words for numbers in the teens
must be memorized one by one. (Data from
K. F. Miller et al., 1995)

U N D E R S T A N D I N G W H Y , W H E R E , W H E N , A N D H o W M A N Y n 293
of whether the habituated dimension was size, number, or time, and regardless of
whether the dimension that subsequently varied was size, number, or time.
Other studies report the same conclusion (de Hevia & Spelke, 2010;
Srinivasan & Carey, 2010). For instance, the ratios required for infants of a given
age to discriminate between two stimuli are similar regardless of whether the dis-
crimination involves time, space, or number (Brannon, Lutz, & Cordes, 2006;
Brannon, Suanda, & Libertus, 2007). Moreover, overlapping brain areas in the
intraparietal sulcus are involved in representing all three dimensions (Dehaene &
Brannon, 2011). Thus, infants appear to have both the general, undifferentiated
concept of magnitude that Piaget hypothesized they have and also the more spe-
cific concepts of time, space, and number that he hypothesized they lack.
review:
A basic understanding of causality emerges extremely early in development. Infants in their
first year distinguish between physical causes, in which actions are produced by direct con-
tact, and psychological causes, in which actions are produced by desires and beliefs. During
the preschool and elementary school periods, children become increasingly adept at inferring
causal relations, even when the relations are more complex and require deeper understand-
ing of causes, effects, and the mechanisms that link them. However, belief in magic and the
supernatural coexist with this growing understanding of causal mechanisms, especially in
the preschool years.
Congruent Trial Incongruent Trial
Habituation Phase
Test Phase
FIGURE 7.10 Infants’ general magnitude representations to test whether infants possess a
general sense of magnitude, Lourenco and Longo (2010) first presented pairs of figures, such as
those in the top panel, in which one decoration (here, black with white stripes) was associated with
the larger value of one quantitative dimension (here, larger size). after this habituation phase, the
infants were shown either congruent trials (bottom left), in which the same decoration accompanied
the choice with the greater quantitative value (here, the greater number of objects), or incongruent
trials (bottom right), in which that decoration accompanied the choice with the smaller quantitative
value (here, the smaller number of objects). regardless of the particular pair of quantitative dimen-
sions used during the habituation and test phases, children looked longer during incongruent trials,
indicating that they expected that particular decoration to continue to accompany the choice with
the larger value on whichever quantitative dimension varied.
C
o
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Y
o
F
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T
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LL
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294 n chapter 7 CoNCEpTUAL DEVELopMENT
People, like other animals, are biologically prepared to code specific types of spatial infor-
mation in specific parts of the brain. From the first year, children represent spatial locations
relative both to their own bodies and to other features of the environment, such as landmarks.
Self-produced movement seems crucial in the further development of spatial representations.
A rudimentary sense of time also is present extremely early: by age 3 months if not earlier,
infants possess a sense of the order in which events happened. However, an accurate sense
of duration doesn’t develop until 3 to 5 years of age, and learning to reason logically about
time takes even longer.
A basic recognition of differences between sets of one, two, and three objects or actions
is present in the first year, as is ability to discriminate between larger sets whose numbers
differ by substantial ratios. However, not until age 3 or 4 years do children show precise un-
derstanding with sets larger than three. During the preschool period, children also learn the
principles underlying counting, such as that each object must be counted once and only
once. By age 5 years, most also learn the number system of their language. Learning of
counting is influenced by the regularity of the number system in the child’s language as well
as by the culture’s emphasis on mathematics.
In addition to specific representations of space, time, and number, infants also possess a
general representation of magnitude that extends across all three dimensions. If a decoration
is associated with the larger value on one of the three dimensions, infants expect the decora-
tion to accompany the larger value on the other dimensions as well. The overlap in the brain
areas in which the three dimensions are represented probably contributes to this general rep-
resentation of magnitude.
chapter summary:
To understand their experiences, children must learn that
the world includes several types of objects: people, other liv-
ing things, and inanimate objects. Children also need a basic
understanding of causality, space, time, and number, so that
they will be able to code their experiences in terms of why,
where, when, and how often events occurred.
Understanding Who or What
n Early categories of objects are based in large part on perceptual
similarity, especially similarity in the shapes of the objects.
n By age 2 or 3 years, children form category hierarchies: animal/
dog/poodle, furniture/chair/La-Z-Boy, and so on.
n From infancy onward, children differentiate people from other
animals and inanimate objects. For example, infants smile
more at people than at either rabbits or robots.
n By age 4 or 5 years, preschoolers develop a rudimentary but
well-organized theory of mind, within which they organize
their understanding of people’s behavior. A key assumption of
this theory of mind is that desires and beliefs motivate specific
actions.
n Understanding that other people will act on their beliefs, even
when the beliefs are false, is very difficult for 3-year-olds;
many children do not gain this understanding until age 5.
n Animals and plants, especially animals, are of great interest to
young children. When animals are present, infants and tod-
dlers pay careful attention to them.
n By age 4 years, children develop an elaborate understanding
of living things, including coherent ideas about invisible pro-
cesses such as growth, inheritance, illness, and healing. Both
their natural fascination with living things and the input they
receive from the environment contribute to their knowledge
about plants and animals.
Understanding Why, Where, When, and How Many
n The development of causal reasoning about physical events
begins in infancy. By 6 to 12 months, infants understand the
likely consequences of objects colliding. Understanding causal
relations among actions helps 1-year-olds remember them.
n By 4 or 5 years, children seem to realize that causes are neces-
sary for events to occur. When no cause is obvious, they search
for one. However, many preschoolers believe in magic as well
as physical cause–effect relations.
n People, like other animals, are biologically prepared to code
space. Early in infancy, they code locations of other objects in
relation to their own location and to landmarks. As they gain
the ability to move around on their own, children gain a sense

C H A p T E R S U M M A R Y n 295
of locations relative to the overall environment as well as to
their own current location.
n Children who are born blind have surprisingly good repre-
sentations of space, though some aspects of their spatial pro-
cessing, especially processing of faces, remain poor even if
corrective surgery is performed during infancy.
n Just as infants are born with an ability to code some aspects
of space, so they are born with an ability to code some aspects
of time. Even 3-month-olds code the order in which events
occur. Infants of that age also can use consistent sequences of
past events to anticipate future events.
n By age 5 years, children also can reason about time, in the
sense of inferring that if two events started at the same time,
and one stopped later than the other, the event that stopped
later took longer. However, they can do this only when inter-
fering perceptual cues are absent.
n Rudimentary understanding of very small numbers is present
from early in infancy. Infants notice numerical differences
between small sets of objects and between events that are
repeated a different number of times. They also notice dif-
ferences between larger sets when the numbers of objects or
events in the sets differ by large ratios.
n By age 3 years, most children learn to count 10 objects. Their
counting seems to reflect understanding of certain principles,
such as that each object should be labeled by a single number
word. Children’s subsequent rate of learning about numbers
reflects their culture’s number system and the degree to which
their culture values numerical knowledge.
n From infancy onward, children also possess a general repre-
sentation of magnitude that extends at least to space, time, and
number.
Critical Thinking Questions
1. Why is it useful for people to organize categories into hierar-
chies, such as animal/dog/poodle or vehicle/car/Prius?
2. Did you have an imaginary companion as a child or know
someone who did? What functions did the invisible friend
serve, and why do you think that you or the other person
stopped imagining the companion?
3. Why do you think 5-year-olds are so much better at false-
belief problems than 3-year-olds are?
4. Self-produced movement enhances children’s representation
of space. What evolutionary purpose might this serve?
5. Describe the thoughts that might go through a 5-year-old’s
mind when the child sees two Santa Clauses walking past
each other.
6. Do you think infants possess a basic understanding of arith-
metic? Why or why not?
7. Why might it be useful for children to have a general rep-
resentation of quantity, as well as specific representations of
space, time, and number?
Key Terms
basic level, p. 264
category hierarchy, p. 263
concepts, p. 260
egocentric spatial representations,
p. 284
essentialism, p. 276
false-belief problems, p. 268
naïve psychology, p. 266
numerical equality, p. 289
object substitution, p. 271
perceptual categorization, p. 264
pretend play, p. 271
sociodramatic play, p. 271
subitizing, p. 290
subordinate level, p. 264
superordinate level, p. 264
theory of mind, p. 267
theory of mind module (TOMM), p. 269

296
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A L I C E K E N T S TO D D A R D, On the Chaise, 1930

297
Intelligence and
Academic Achievement
n What Is Intelligence?
Intelligence as a Single Trait
Intelligence as a Few Basic Abilities
Intelligence as Numerous Processes
A Proposed Resolution
Review
n Measuring Intelligence
The Contents of Intelligence Tests
The Intelligence Quotient (IQ)
Continuity of IQ Scores
Box 8.1: Individual Differences Gifted Children
Review
n IQ Scores as Predictors of
Important Outcomes
Review
n Genes, Environment, and the Development
of Intelligence
Qualities of the Child
Influence of the Immediate Environment
Influence of Society
Box 8.2: Applications A Highly Successful
Early Intervention: The Carolina
Abecedarian Project
Review
n Alternative Perspectives on Intelligence
Review
n Acquisition of Academic Skills: Reading,
Writing, and Mathematics
Reading
Box 8.3: Individual Differences Dyslexia
Writing
Mathematics
Mathematics Anxiety
Box 8.4: Applications Mathematics Disabilities
Review
n Chapter Summary
chapter 8:

298
I
n 1904, the minister of education of France faced a problem. France, like other
western European and North American countries, had recently introduced uni-
versal public education, and it was becoming apparent that some children were
not learning well. Therefore, the minister wanted a means of identifying chil-
dren who would have difficulty succeeding in standard classrooms, so that they
could be given special education. His problem was how to identify such children.
One obvious way was to ask teachers to indicate which students in their class-
rooms were encountering difficulty. However, the minister worried that teachers
might be biased in their assessments. In particular, he was concerned that some
teachers would be prejudiced against poor children and would claim that those
children were unable to learn, even if they actually could. He therefore asked Alfred
Binet, a French psychologist who had studied intelligence for 15 years, to develop
an easy-to-administer, objective test of intelligence.
The prevailing view at the time was that intelligence is based on simple skills,
such as associating objects with the sounds they make (e.g., ducks with quacking,
bells with ringing), responding quickly to stimuli, and recognizing whether two
objects are identical. According to this view, children who are more adept than
their peers at such simple skills learn more quickly and thus become more intel-
ligent. The theory was plausible—but wrong. It is now clear that simple skills are
only modestly related to broader, everyday indicators of intelligence, such as school
performance.
Binet’s theory differed from the prevailing wisdom of his time. He believed that
the key components of intelligence are high-level abilities, such as problem solving,
reasoning, and judgment, and he maintained that intelligence tests should assess
such abilities directly. Therefore, on the test that he and his colleague Théophile
Simon devised—the Binet-Simon Intelligence Test—children were asked (among
other things) to interpret proverbs, solve puzzles, define words, and sequence car-
toon panels so that the jokes made sense.
Binet’s approach was successful in identifying children who would have diffi-
culty learning from classroom instruction. More generally, children’s performance
on the Binet-Simon test correlated highly not only with their school grades at the
time of testing but also with their grades years later. The test was also successful in
establishing a goal of intelligence testing that has been pursued ever since—to pro-
vide an objective measure of scholastic aptitude that would allow fairer decisions
about children’s schooling, including which children should be in honors classes,
which are in need of special education, which should be admitted to highly selec-
tive colleges, and so on.
In addition to the practical impact of his test, Binet’s theoretical approach to
intelligence has continued to influence research on the topic to this day. In most
areas of cognitive development—perception, language, conceptual understanding,
and so on—the emphasis is on age-related changes: the ways in which younger
children differ from older ones. Following Binet’s lead, however, research on intelli-
gence has focused on individual differences—on how and why children of the same
age differ from one another, and on the continuity of such individual differences
over time. The nature of individual differences is an enduring theme throughout
the field of child development, but the focus on it is especially intense in the study
of intelligence.
Questions regarding the development of intelligence excite strong passions, and
no wonder. Research in this area raises many of the most basic issues about human
Themes
n Nature and Nurture
n The Active Child
n Continuity/Discontinuity
n Mechanisms of Change
n The Sociocultural Context
n Individual Differences
n Research and Children’s
Welfare

W h A T I S I n T E L L I G E n C E ? n 299
nature: the roles of heredity and environment, the influence of ethnic and racial
differences, the effects of wealth and poverty, and the possibility of improvement.
Almost everyone has opinions, often heartfelt ones, about why some people are
more intelligent than others.
Intelligence research also has added greatly to understanding all the major
themes emphasized in this book: the nature and origins of individual differences,
the contributions of the active child and of the sociocultural context, the way in which
nature and nurture together shape development, the degree of continuity in a key
human trait, the mechanisms that produce changes, and the relation between research
and children’s welfare. Before examining research on the development of intelli-
gence, however, we must examine a question that sounds simple but actually lies at
the heart of many controversies: What is intelligence?
What Is Intelligence?
Intelligence is notoriously difficult to define, but this has not kept people from try-
ing. Part of the difficulty is that intelligence can legitimately be described at three
levels of analysis: as one thing, as a few things, or as many things.
Intelligence as a Single Trait
Some researchers view intelligence as a single trait that influences all aspects of
cognitive functioning. Supporting this idea is the fact that performance on all intel-
lectual tasks is positively correlated: children who do well on one tend to do well on
others, too (Geary, 2005). These positive correlations occur even among dissimilar
intellectual tasks—for example, remembering lists of numbers and folding pieces
of paper to reproduce printed designs. Such omnipresent positive correlations have
led to the hypothesis that each of us possesses a certain amount of g, or general
intelligence, and that g influences our ability to think and learn on all intellectual
tasks (A. R. Jensen, 1998; Spearman, 1927).
Numerous sources of evidence attest to the usefulness of viewing intelligence as a
single trait. Measures of g, such as overall scores on intelligence tests, correlate posi-
tively with school grades and achievement test performance (Gottfredson, 2011).
At the level of cognitive and brain mechanisms, g correlates with information-
processing speed (Coyle et al., 2011; Deary, 2000), speed of neural transmission
(Vernon et al., 2000), and brain volume (McDaniel, 2005). Measures of g also cor-
relate strongly with people’s knowledge of subjects—such as medicine, law, art his-
tory, and the Bible—that are not taught in school (Lubinski & Humphreys, 1997).
Such evidence supports the view of intelligence as a single trait that involves the
ability to think and learn.
Intelligence as a Few Basic Abilities
There are also good arguments for viewing intelligence as more than a single gen-
eral trait. The simplest such view holds that there are two types of intelligence: fluid
intelligence and crystallized intelligence (Cattell, 1987):
n Fluid intelligence involves the ability to think on the spot—for example, by
drawing inferences and understanding relations between concepts that have
not been encountered previously. It is closely related to adaptation to novel
g (general intelligence) n cognitive
processes that influence the ability to
think and learn on all intellectual tasks
fluid intelligence n ability to think on
the spot to solve novel problems

300 n chapter 8 InTELLIGEnCE AnD ACADEmIC AChIEVEmEnT
tasks, speed of information processing, working-memory functioning, and
ability to control attention (C. Blair, 2006; Geary, 2005).
n Crystallized intelligence is factual knowledge about the world: knowledge of
word meanings, state capitals, answers to arithmetic problems, and so on. It
reflects long-term memory for prior experiences and is closely related to verbal
ability.
The distinction between fluid and crystallized intelligence is supported by the
fact that tests of each type of intelligence correlate more highly with each other
than they do with tests of the other type ( J. L. Horn & McArdle, 2007). Thus,
children who do well on one test of fluid intelligence tend to do well on other
tests of fluid intelligence but not necessarily on tests of crystallized intelligence.
In addition, the two types of intelligence have different developmental courses.
Crystallized intelligence increases steadily from early in life to old age, whereas
fluid intelligence peaks around age 20 and slowly declines thereafter (Salthouse,
2009). The brain areas most active in the two types of intelligence also differ: the
prefrontal cortex usually is especially active on measures of fluid intelligence but
tends to be much less active in measures of crystallized intelligence (C. Blair, 2006;
Jung & Haier, 2007).
A somewhat more differentiated view of intelligence (Thurstone, 1938) pro-
poses that the human intellect is composed of seven primary mental abilities:
word fluency, verbal meaning, reasoning, spatial visualization, numbering, rote
memory, and perceptual speed. The key evidence for the usefulness of dividing
intelligence into these seven abilities is similar to that for the distinction between
fluid and crystallized intelligence. Scores on various tests of a single ability tend to
correlate more strongly with each other than do scores on tests of different abilities.
For example, although both spatial visualization and perceptual speed are measures
of fluid intelligence, children tend to perform more similarly on two tests of spatial
visualization than they do on a test of spatial visualization and a test of perceptual
speed. The trade-off between these two views of intelligence is between the sim-
plicity of the crystallized/fluid distinction and the greater precision of the idea of
seven primary mental abilities.
Intelligence as Numerous Processes
A third view envisions intelligence as comprising numerous, distinct processes.
Information-processing analyses of how people solve intelligence test items and
how they perform everyday intellectual tasks such as reading, writing, and arith-
metic reveal that a great many processes are involved (e.g., Geary, 2005). These
include remembering, perceiving, attending, comprehending, encoding, associating,
generalizing, planning, reasoning, forming concepts, solving problems, generating
and applying strategies, and so on. Viewing intelligence as “many processes” allows
more precise specification of the mechanisms involved in intelligent behavior than
do approaches that view it as “a single trait” or “several abilities.”
A Proposed Resolution
How can these competing perspectives on intelligence be reconciled? After study-
ing intelligence for more than half a century, John B. Carroll (1993, 2005) proposed
a grand integration: the three-stratum theory of intelligence (Figure 8.1). At
the top of the hierarchy is g; in the middle are several moderately general abilities
crystallized intelligence n factual
knowledge about the world
primary mental abilities n seven abil-
ities proposed by Thurstone as crucial to
intelligence
three-stratum theory of intelligence
n Carroll’s model that places g at the top
of the intelligence hierarchy, eight moder-
ately general abilities in the middle, and
many specific processes at the bottom

m E A S U R I n G I n T E L L I G E n C E n 301
(which include both fluid and crystallized intelligence and other competencies
similar to Thurstone’s seven primary mental abilities); at the bottom are many spe-
cific processes. General intelligence influences all moderately general abilities, and
both general intelligence and the moderately general abilities influence the specific
processes. For instance, knowing someone’s general intelligence allows for a fairly
reliable prediction of the person’s general memory skills; knowing both of them
allows quite reliable prediction of the person’s memory span; and knowing all three
allows very accurate prediction of the person’s memory span for a particular type of
material, such as words, letters, or numbers.
Carroll’s comprehensive analysis of the research literature indicated that all three
levels of analysis that we have discussed in this section are necessary to account
for the totality of facts about intelligence. Thus, for the question “Is intelligence a
single trait, a few abilities, or many processes?” the correct answer seems to be “All
of the above.”
review:
Intelligence can be viewed as a single general ability to think and learn; as several moderately
general abilities, such as crystallized and fluid intelligence; or as a collection of numerous
specific skills, processes, and content knowledge. All three levels are useful for understand-
ing intelligence.
Measuring Intelligence
Although intelligence is usually viewed as an invisible capacity to think and learn,
any measure of it must be based on observable behavior. Thus, when we say that
a person is intelligent, we mean that the person acts in intelligent ways. One of
Binet’s profound insights was that the best way to measure intelligence is by observ-
ing people’s actions on tasks that require a variety of types of intelligence: problem
solving, memory, language comprehension, spatial reasoning, and so on. Modern
intelligence tests continue to sample these and other aspects of intelligence.
Intelligence testing is highly controversial. Critics such as Ceci (1996) and
Sternberg (2008) argue that measuring a quality as complex and multifaceted as
General intelligence g
Fluid
intelligence
Crystallized
intelligence
General memory
and learning
Broad visual
perception
Broad auditory
perception
Broad retrieval
ability
Broad cognitive
speediness
Processing
speed
• Sequential
reasoning
• Induction
• Quantitative
reasoning
• Printed
language
• Language
comprehension
• Vocabulary
knowledge
• Memory
span
• Associative
memory
• Visualization
• Spatial relations
• Closure speed
• Speech sound
discrimination
• General sound
discrimination
• Creativity
• Ideational
fluency
• Naming
facility
• Rate of
test taking
• Numerical
facility
• Perceptual
speed
• Simple
reaction time
• Choice
reaction time
• Semantic
processing
speed
FIGURE 8.1 carroll’s three-stratum
theory of intelligence In carroll’s hierarchy,
general intelligence (g) influences several
intermediate-level abilities, and each
intermediate-level ability influences a
variety of specific processes. as this model
suggests, intelligence can be usefully
viewed as a single entity, as a small set
of abilities, or as a very large number of
particular processes.

302 n chapter 8 InTELLIGEnCE AnD ACADEmIC AChIEVEmEnT
intelligence requires assessing a much broader range of abilities than are assessed
by current intelligence tests; that current intelligence tests are culturally biased; and
that reducing a person’s intelligence to a number (the IQ score) is simplistic and
ethically questionable. In contrast, advocates (e.g., Gottfredson, 1997; J. L. Horn &
McArdle, 2007) argue that intelligence tests are better than any alternative method
for predicting important outcomes such as school grades, achievement test scores,
and occupational success; that they are valuable for making decisions such as which
children should be given special education; and that alternative methods for mak-
ing educational decisions, such as evaluations by teachers or psychologists, may be
subject to greater bias. Knowing the facts about intelligence tests and understand-
ing the issues surrounding their use is crucial to generating informed opinions
about these issues.
The Contents of Intelligence Tests
Intelligence is reflected in different abilities at different ages. For example, language
ability is not a part of intelligence at 4 months of age, because infants this young
neither produce nor understand words, but it is obviously a vital part of intelligence
at 4 years of age. The items on tests developed to measure intelligence at different
ages reflect these changing aspects. For instance, on the Stanford-Binet intelli-
gence test (a descendant of the original Binet-Simon test), 2-year-olds are asked to
identify the objects depicted in line drawings (a test of object recognition), to find
an object that they earlier had seen hidden (a test of learning and memory), and to
place each of three objects in a hole of the proper shape (a test of perceptual skill
and motor coordination). The version of the Stanford-Binet presented to 10-year-
olds asks them to define words (a test of verbal ability), to explain why certain social
institutions exist (a test of general information and verbal reasoning), and to count
the blocks in a picture in which the existence of some blocks must be inferred (a
test of problem solving and spatial reasoning).
Intelligence tests have had their greatest success and widest application with
children who are at least 5 or 6 years old. The exact abilities examined, and the
items used to examine them, vary somewhat from test to test, but there is also con-
siderable similarity among the leading tests.
The most widely used intelligence testing instrument for children 6 years and
older is the Wechsler Intelligence Scale for Children ( WISC). The current edi-
tion, the WISC-IV, was revised in 2003 to reflect modern theoretical conceptions
of intelligence and the current population of children in the United States, which
is more diverse, both linguistically and culturally, than it was when the WISC was
previously revised in the 1990s.
The conception of intelligence underlying the WISC-IV is consistent with
Carroll’s three-stratum framework, proposing that intelligence includes gen-
eral ability (g), several moderately general abilities, and a large number of spe-
cific skills. The test yields not only an overall score but also separate scores on
four moderately general abilities—verbal comprehension, perceptual reasoning,
working memory, and processing speed. The WISC-IV measures these abili-
ties because they reflect skills that are important within information-processing
theories, correlate positively with other aspects of intelligence, and are related to
important outcomes, notably school grades and later occupational success (Flana-
gan & Kaufman, 2004). Figure 8.2 provides examples of the four types of items
that appear on the WISC-IV (the actual items are protected by copyrights and
thus cannot be reprinted).
Wechsler Intelligence Scale for
Children (WISC) n widely used test
designed to measure the intelligence of
children 6 years and older

m E A S U R I n G I n T E L L I G E n C E n 303
FIGURE 8.2 Four abilities tested by
WISc-IV this figure shows examples of the
types of items used on the WISc-IV to mea-
sure four aspects of children’s intelligence.
On most subtests, the measure of perfor-
mance is simply whether answers are cor-
rect, but on some, such as “perceptual
speed,” the measure of performance is the
number of correct answers that are gener-
ated in a limited time. these are not actual
items from the test but rather are of the
same type; copyright laws prevent the repro-
duction of the actual items.
YES
NO
Typical Verbal Comprehension Items
Vocabulary “What is a helicopter?”
Similarities “How are a mountain and a river alike?”
Typical Perceptual Reasoning Items
Block design “Make these nine blocks look exactlly like the picture.”
Typical Working Memory Items
Digit span “Repeat the following numbers in order when I’m finished: 5, 3, 7, 4, 9.” “Now say these
numbers from last to first: 2, 9, 5, 7, 3.”
Letter-number sequencing “Repeat the numbers from smallest to biggest, then repeat the letters
from earliest to latest in the alphabet: 4, D, 2, G, 7.”
Typical Perceptual Speed Items
Coding “Under each square, put a plus; under each circle, put a minus; under each triangle, put an X.”
Symbol search “Does the figure to the left of the vertical line also appear to the right of the line?”
Picture concepts “Pick an object from each pair to make a group of objects that go together”

304 n chapter 8 InTELLIGEnCE AnD ACADEmIC AChIEVEmEnT
The Intelligence Quotient (IQ)
Intelligence tests such as the WISC and the Stanford-Binet provide an overall
quantitative measure of a child’s intelligence relative to that of other children of
the same age. This summary measure is referred to as the child’s IQ (intelligence
quotient).
Understanding how IQ scores are computed, and why, requires a little back-
ground. Early developers of intelligence tests observed that many easy-to-
measure human characteristics, such as men’s heights, women’s heights, men’s
weights, and women’s weights, fall into a normal distribution. As shown in
Figure 8.3, normal distributions are symmetrical around a mean (average) value,
with most scores falling relatively near the mean. The farther a score is from the
mean, the smaller the percentage of people who obtain it. For example, the mean
height of adult males in the United States is around 5 feet 10 inches. Many men
are 5 feet 9 inches or 5 feet 11 inches, but few men are 5 feet 2 inches or 6 feet 6
inches. The farther from the mean a height falls, the smaller the number of men
of that height.
–3 SD Mean +3 SD–2 SD +1 SD +2 SD–1 SD
55
0.13% 13.59% 34.13% 34.13% 13.59% 2.14% 0.13%2.14%
70 85 100 115 130 145
FIGURE 8.3 a normal distribution of
IQ scores Like other measurable human
characteristics, IQ scores fall into a normal
distribution. here, the numbers along the
base of the graph correspond to IQ scores.
the number just below each IQ score indi-
cates how many standard deviation units
that score is below or above the mean. thus,
an IQ score of 55 is 3 standard deviations
below the mean. the percentages in each
interval indicate the percentage of children
whose scores fall within that interval; for
example, less than 1% of children have IQ
scores below 55 and slightly more than 2%
score between 55 and 70.
Similarly, the normal distribution found in intelligence test scores of children
of a given age means that most IQ scores are fairly close to the mean, with few
children obtaining very high or very low scores. Early designers of IQ tests made
an arbitrary decision that has been maintained ever since: a score of 100 is given
to children who score exactly at the mean for their age at the time the test is
developed. (The mean score can rise or fall in the years after a particular test is
developed and, indeed, as discussed later in this chapter, IQ scores on specific
tests have risen throughout the industrialized world over the past century.)
IQ scores reflect not only the mean for the test but also its standard deviation
(SD), a measure of the variability of scores within a distribution. By definition,
in a normal distribution, 68% of scores fall between 1 SD below the mean and
1 SD above it, and 95% of scores fall between 2 SDs below the mean and 2 SDs
above it.
On most IQ tests, the standard deviation is about 15 points. Thus, as shown
in Figure 8.3, a child scoring 1 standard deviation above the mean for his or her
IQ (intelligence quotient) n quantita-
tive measure, typically with a mean of
100 and a standard deviation of 15, used
to indicate a child’s intelligence relative
to that of other children of the same age
normal distribution n pattern of data
in which scores fall symmetrically around
a mean value, with most scores falling
close to the mean and fewer and fewer
scores farther from it
standard deviation (SD) n measure of
the variability of scores in a distribution;
in a normal distribution, 68% of scores
fall within 1 SD of the mean, and 95% of
scores fall within 2 SDs of the mean

m E A S U R I n G I n T E L L I G E n C E n 305
age (a score higher than 84% of children) receives a score of 115 (the mean of
100 plus the 15-point SD). Similarly, a child scoring 1 standard deviation below
the mean (a score higher than only 16% of children) receives a score of 85 (the
mean of 100 minus the SD of 15). Figure 8.3 also reflects the fact that about 95%
of children obtain IQ scores that fall within 2 standard deviations of the mean
(between 70 and 130).
An advantage of this scoring system is that IQ scores at different ages are easy to
compare, despite the great increases in knowledge that accompany development in
all children. A score of 130 at age 5 means that a child’s performance exceeded that
of 98% of age peers; a score of 130 at age 10 or 20 means exactly the same thing.
This property has facilitated analysis of the stability of individuals’ IQ scores over
time, a topic we turn to next.
Continuity of IQ Scores
If IQ is a consistent property of a person, then the IQ scores that people
obtain at different ages should be highly correlated. Longitudinal studies that
have measured the same children’s IQ scores at different ages have, in fact, shown
impressive continuity from age 5 onward. For example, one study
indicated that children’s IQ scores at ages 5 and 15 correlated
0.67 (Humphreys, 1989). This is a remarkable degree of continu-
ity over a 10-year period. (Recall from Chapter 1 that a correla-
tion of 1.00 indicates that two variables are perfectly correlated.)
Indeed, the IQ score may be the most stable of all psychological
traits (N. Brody, 1992).
Several variables influence the degree of stability of IQ scores
over time. As might be expected, the closer in time that IQ tests
are given, the more stability is found. Thus, the same study that
found that IQ scores at ages 5 and 15 correlated 0.67 also found
that scores at ages 5 and 9 correlated 0.79 and at ages 5 and 6 cor-
related 0.87. In addition, for any given length of time between
tests, scores are more stable at older ages. For instance, in one
study, IQ scores of 4- and 5-year-olds correlated 0.80, those of 6-
and 7-year-olds correlated 0.87, and those of 8- and 9-year-olds
correlated 0.90 (N. Brody, 1992).
Although a person’s IQ scores at different ages tend to be simi-
lar, the scores are rarely identical. Children who take an IQ test
at age 4 and again at age 17 show an average change, up or down,
of 13 points; those who take the test at ages 8 and 17 show an
average change of 9 points; and those who take it at ages 12 and
17 show an average change of 7 points (N. Brody, 1992). These
changes are due at least in part to random variation in factors
such as the child’s alertness and mood on the test days. Changes in the child’s
environment, such as those associated with parental divorce or remarriage or
moving to a better or worse neighborhood, also can produce changes in IQ score
(Sameroff et al., 1993).
A question of interest to parents and scientists alike is whether it is possible to
identify at young ages children who are superior in intelligence or in specific intel-
lectual or artistic abilities. Research on such children, who are often described as
“gifted,” is presented in Box 8.1.
the IQ scores of children whose parents
take an interest in their academic success
tend to increase over time.
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306 n chapter 8 InTELLIGEnCE AnD ACADEmIC AChIEVEmEnT
review:
Intelligence tests examine a range of abilities and types of knowledge, including vocabu-
lary, verbal comprehension, arithmetic, memory, and spatial reasoning. The tests are used to
obtain a general measure of intelligence: the IQ score. IQ tests are designed to produce aver-
age scores of 100, with higher scores indicating above-average intelligence and lower scores
below-average intelligence. After age 5 or 6, IQ scores of individual children tend to be quite
stable over long periods, but they vary somewhat from one testing to the next.
KyLee was already fascinated by numbers at
age 18 months. His favorite toys were plas-
tic numbers and blocks with numbers on
them. As he played with these toys, he said
the number names over and over. When he
was 2 years old, he saw a license plate with
two 8s on it and said “8 1 8 5 16.” Nei-
ther he nor his parents could explain how he
knew this. By age 3 years, KyLee was play-
ing math games on a computer every day.
During one such game, he discovered the
idea of prime numbers and thereafter was
able to identify new prime numbers. Again,
neither he nor his parents knew how he did
this.
Before he entered kindergarten, KyLee
could add, subtract, multiply, divide, esti-
mate, and solve complex word problems.
When asked if he ever got tired of numbers,
he said, “No, never” and said that he was a
“number boy” (Winner, 1996, pp. 38–39).
He went on to represent his state in the na-
tional MATHCOUNTS competition when he
was a 7th grader, is now majoring in com-
puter science at an Ivy League university,
and plans on devoting his career to improv-
ing the efficiency of everyday life activities
through the development of superior algo-
rithms (E. Winner, personal communication,
December 26, 2012).
As noted by Ellen Winner, a psycholo-
gist who studies intellectually and artisti-
cally gifted children, most, like KyLee, show
astonishing early facility in a single area:
numbers, music, drawing, reading, or some
other realm. A smaller number of children
are exceptional over a wide range of intellec-
tual areas. These globally gifted children usu-
ally display several signs of giftedness from
very early in development (N. M. Robinson &
Robinson, 1992):
• Unusual alertness and long attention
span in infancy
• Rapid language development
• Curiosity—asking deep questions and
being dissatisfied with superficial answers
• High energy levels, often bordering on
hyperactivity
• Intense reactions to frustration
• Precocious reading and interest in
numbers
• Exceptional logical and abstract reasoning
• Unusually good memory
• Enjoyment of solitary play
Exceptional early ability often foreshad-
ows outstanding later achievement. Consider
a long-term study of 320 children who took
the SAT by age 13 as part of a national tal-
ent search and who scored in the top 1 in
10,000 in verbal or math ability. Among their
accomplishments by age 23 were adapt-
ing Pink Floyd’s The Wall into a multi media
rock opera, developing one of the most pop-
ular video games in the United States, and
inventing a navigation system that was used
to land a rocket on Mars (Lubinski et al.,
2001). As a group, they had published 11
articles in scientific and medical journals
and won numerous major awards in areas
ranging from physics to creative writing.
By age 33, more than half of the origi-
nal sample had received a PhD, MD, or JD
(Lubinski et al., 2006). Their rate of PhDs
was more than 50 times higher than that for
the general population, and their rate of pat-
ents was 11 times that in the general popu-
lation. Even within this elite sample, higher
initial SAT mathematics scores predicted
BOX 8.1: individual differences
GIFTED CHILDREN
higher achievement. For example, the higher
the score on the SAT math test at age 13, the
greater the number of patents and publica-
tions in scholarly journals—especially those
in science, engineering, and mathematics—
at age 33 (Park, Lubinski, & Benbow, 2008).
Exceptional early ability in an area is no
guarantee of outstanding adult achievement
in it. Factors such as creativity, devotion to
the area, ability to work long hours, and per-
severance in the face of difficulty are also
essential for making exceptional contribu-
tions (Lubinski & Benbow, 2006; Wai et
al., 2010). Nonetheless, it is remarkable
how scores on a single test, given at age 13
years, predict exceptional achievement 20
years later.
exceptionally early readers, such as this
3½-year-old, often continue to be excellent
readers throughout life.
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I Q S C O R E S A S P R E D I C T O R S O f I m P O R T A n T O U T C O m E S n 307
IQ Scores as Predictors of Important Outcomes
Claims that an IQ score is a strong predictor of academic, economic, and occupa-
tional success are based on solid evidence (Sackett, Borneman, & Connelly, 2008;
F. L. Schmidt & Hunter, 2004). As noted earlier, IQ scores correlate positively and
quite strongly with school grades and achievement test performance, both at the
time of the test and years later (Geary, 2005); for example, IQ and achievement
test performance typically correlate between 0.50 and 0.60 (Deary et al., 2007). IQ
scores also correlate positively with long-term educational outcomes. In the United
States, a person’s IQ score in 6th grade correlates about 0.60 with the years of edu-
cation that the person eventually completes ( Jencks, 1979). Substantial relations
between IQ score and performance in intellectually demanding occupations are
present not only when the person is hired but for at least 10 years after entry into
the occupation (Sackett et al., 2008).
In part, the positive relation between IQ score and occupational and economic
success stems from the fact that standardized test scores serve as gatekeepers,
determining which students gain access to the training and credentials required for
entry into lucrative professions. Even among people who initially have the same
job, however, those with higher IQ scores tend to perform better, earn more money,
and receive better promotions (F. L. Schmidt & Hunter, 2004; Wilk, Desmarais,
& Sackett, 1995).
A child’s IQ score is more closely related to the child’s later occupational success
than is the socioeconomic status of the child’s family, the school the child attends,
or any other variable that has been studied (Ceci, 1993). These relations hold even
at the top of the test score distribution. Although popular books such as Outliers
(Gladwell, 2008) claim that people with fairly high test scores achieve grades and
occupational success equivalent to those of people with very high scores, empiri-
cal research indicates that even at the top of the distribution, the higher the test
score, the higher that subsequent achievement is likely to be (Arneson, Sackett, &
Beatty, 2011).
As strong a predictor of academic, economic, and occupational success as IQ score
is, intelligence is far from the only influence. A child’s other characteristics, such as
motivation to succeed, conscientiousness, intellectual curiosity, creativity, physical and
mental health, and social skills, also exert important influences (Roberts et al., 2007;
Sternberg, 2004; von Stumm, Hell, & Charmorro-Premuzic, 2011). For instance,
self-discipline—the ability to inhibit actions, follow rules, and avoid impulsive
reactions— is more predictive of changes in report card grades between 5th and 9th
grades than is IQ score, though IQ score is more predictive
of changes in achievement test scores over the same period
(Duckworth, Quinn, & Tsukayama, 2012). Similarly, “prac-
tical intelligence”—skills that are useful in everyday life but
that are not measured by traditional intelligence tests, such as
accurately reading other people’s emotions and intentions and
motivating others to work effectively as a team—predicts occu-
pational success beyond the influence of IQ score (Cianciolo et
al., 2006; Sternberg, 2003). Characteristics of the environment
are similarly influential: parents’ encouragement and modeling
of productive careers predict their children’s occupational suc-
cess (Kalil, Levine, & Ziol-Guest, 2005).
Figure 8.4 illustrates how the same set of data can simul-
taneously provide evidence for the importance of IQ score
self-discipline n ability to inhibit
actions, follow rules, and avoid impulsive
reactions
650
600
550
500
450
400
350
300
250
200
1
9
9
2
w
ee
kl
y
w
ag
es
IQ Quintile IQ Quintile IQ Quintile
High school 2-Year college 4-Year college
FIGURE 8.4 effects of intelligence
and education on income Intelligence
influences income, but so do other factors,
such as education. these data indicate the
average income of people who received dif-
ferent levels of education and who scored
in different quintiles (fifths) of the IQ distri-
bution. Within any given educational level,
people with higher IQ scores earned more.
thus, among people with only a high school
education, those who scored in the bottom
20% on an IQ test (the blue bar) averaged
only a little more than $250/week, but those
who scored in the top 20% (the purple bar)
averaged almost $450/week. people in the
top 20% in IQ score earned considerably
more, but here too education mattered:
those with high IQ scores who had only a
high school education earned an average
of roughly $450/week, whereas those with
comparable IQ scores and a four-year col-
lege education earned almost $650/week.
(Data from ceci, 1996)

308 n chapter 8 InTELLIGEnCE AnD ACADEmIC AChIEVEmEnT
and other factors. Consistent with the importance of IQ, the figure shows that,
among people with the same level of education, those with higher IQ scores earn
more money. Consistent with the importance of other factors, the figure shows
that, among people with comparable IQ scores, those who complete more years
of education earn more money. Thus, while IQ is a key contributor to educational,
occupational, and economic success, numerous social and motivational factors are
also crucial.
review:
IQ scores are positively related to grades in school and achievement test performance, both
at the time of the test and in the future. They are also positively related to occupational suc-
cess in adulthood. However, they are not the only influence on these outcomes. Intellectual
curiosity, creativity, self-discipline, social skills, practical intelligence, and a variety of other
factors also contribute.
Genes, Environment, and the Development
of Intelligence
No issue in psychology has produced more acrimonious debate than the issue of
how heredity and environment influence intelligence. Even people who recognize
that intelligence, like all human qualities, is constructed through the continuous
interaction of genes and environment often forget this fact and take extreme posi-
tions that are based more on emotions and ideology than on logic and evidence.
A useful starting point for thinking about genetic and environmental influences
on intelligence is Bronfenbrenner’s (1993) bioecological model of development
(detailed in Chapter 9). This model envisions children’s lives as embedded within a
series of increasingly encompassing environments. The child, with a unique set of
qualities including his or her genetic endowment and personal experiences, is at the
In the movie My Fair Lady, eliza Doolittle
found it easier to don the clothing of an
upper-class lady than to adopt the haughty
reserve viewed as appropriate by that class
at that time. this scene, of opening day
at ascot, as well as the movie as a whole,
makes the argument that differences that
might be attributed to nature are actually
the product of nurture. WA
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G E n E S , E n V I R O n m E n T , A n D T h E D E V E L O P m E n T O f I n T E L L I G E n C E n 309
center. Surrounding the child is the immediate environment, especially the people
and institutions with which the child interacts directly: family, school, classmates,
teachers, neighbors, and so on. Surrounding the immediate environment are more
distant, and less tangible, forces that also influence development: cultural attitudes,
the social and economic system, mass media, the government, and so on. We now
examine how qualities of the child, the immediate environment, and the broader
society contribute to the development of intelligence.
Qualities of the Child
Children contribute greatly to their own intellectual development, through their
genetic endowment, through the reactions they elicit from other people, and
through their choice of environments.
Genetic Contributions to Intelligence
As noted in Chapter 3, the genome has a substantial influence on intelligence. This
genetic influence varies greatly with age (Figure 8.5): it is moderate in early child-
hood and becomes large by adolescence and adulthood (Bouchard, 2004; Plomin et
al., 2008). Reflecting the same trend, the IQ scores
of adopted children and those of their biological
parents become increasingly correlated as the chil-
dren develop, but the scores of adopted children and
their adoptive parents become less correlated over
the course of development (Plomin et al., 1997).
One reason for this increasing genetic influence
is that some genetic processes do not exert their
effects until late childhood or adolescence. For ex-
ample, some connections linking areas in the brain
that are distant from each other are not formed
until adolescence, and the extent of such connec-
tions reflects genetic influences (Thatcher, 1992).
Another reason is that children’s increasing inde-
pendence with age allows them greater freedom
to choose environments that are compatible with
their own genetically based preferences but not
necessarily with those of the parents who are rais-
ing them (McAdams & Olson, 2010).
Advances in genetics have inspired research
aimed at identifying a small set of genes that ex-
plain individual differences in intelligence. These efforts have led to identification of
almost 300 genes that are associated with mental retardation (Inlow & Restifo, 2004)
but none that are consistently related to normal variation in intelligence (Butcher et
al., 2008; Chabris et al., 2012). The most likely explanation is that the genetic contri-
bution to intelligence reflects small contributions from each of a very large number of
genes, as well as complex interactions among them (Nisbett et al., 2012).
Genotype–Environment Interactions
As noted in Chapter 3, the environments children encounter are influenced by their
genotype. Sandra Scarr (1992) proposed that gene–environment relations involve
three types of processes: passive, evocative, and active.
4 to 6 6 to 12 12 to 16 16 to 20 Adult
0.0
0.2
0.4
0.6
0.8
1.0
Va
ri
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c
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p
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Age group
Shared EnvironmentGenetic
FIGURE 8.5 changes with age in fac-
tors influencing intelligence as children
grow into adults, the influence of genetics
on individual differences in intelligence
increases, whereas the influence of shared
aspects of family environment decreases.
(Data from McGue et al., 1993)

310 n chapter 8 InTELLIGEnCE AnD ACADEmIC AChIEVEmEnT
n Active effects of the genotype involve children’s choosing environments that
they enjoy. A high school student who likes reading will borrow books from
the library and obtain books in other ways, regardless of whether he or she was
read to when young.
The evocative and active effects of the genotype help explain how children’s IQ
scores become more closely related over time to those of their biological parents,
even if the children are adopted and never see their biological parents.
Influence of the Immediate Environment
The influence of nurture on the development of intelligence begins with a child’s
immediate environment of families and schools.
Family Influences
If asked to identify the most important environmental influence on their intelli-
gence, most people probably would say, “My family.” Testing the influence of the
family environment on children’s intelligence, however, requires some means of
assessing that environment. How can something as complex and multifaceted as a
family environment be measured, especially when it can be different for different
children in the same family?
Robert Bradley and Bettye Caldwell (1979) tackled this problem by devis-
ing a measure known as the HOME (Home Observation for Measurement of
the Environment). The HOME samples various aspects of children’s home life,
including organization and safety of living space; intellectual stimulation offered by
parents; whether children have books of their own; amount of parent–child interac-
tion; parents’ emotional support of the child; and so on. Table 8.1 shows the items
and subscales used in the original HOME, which was designed to assess the fam-
ily environments of children between birth and age 3 years. Subsequent versions of
the HOME have been developed for application with preschoolers, school-aged
children, and adolescents (Bradley, 1994).
Throughout childhood, children’s IQ scores, as well as their math and reading
achievement scores, are positively correlated with the HOME measure of their fam-
ily environment (Bradley et al., 2001). HOME scores of families of 6-month-olds
children influence their own development:
these children’s joyous reactions to their
father’s reading ensure that he will want to
read to them in the future.
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n Passive effects of the genotype arise when children are raised
by their biological parents. These effects occur not because
of anything the children do but because of the overlap
between their parents’ genes and their own. Thus, children
whose genotypes predispose them to enjoy reading are
likely to be raised in homes with plentiful access to reading
matter, because their parents also like to read. The pas-
sive effects of the genotype help explain why correlations
between biological parents’ and their children’s IQ scores
are higher when the children live with their biological par-
ents than when they live with adoptive parents.
n Evocative effects of the genotype emerge through chil-
dren’s eliciting or influencing other people’s behavior. For
example, even if a child’s parents are not avid readers, they
will read more bedtime stories to a child who is interested
in the stories than to one who is uninterested.

G E n E S , E n V I R O n m E n T , A n D T h E D E V E L O P m E n T O f I n T E L L I G E n C E n 311
correlate positively with the IQ scores of the
same children at age 4 years; similarly, HOME
scores of 2-year-olds correlate positively with
IQ scores and school achievement of the
same children at age 11 years (Olson, Bates,
& Kaskie, 1992). When HOME scores are
relatively stable over time, IQ scores also tend
to be stable; when HOME scores change, IQ
scores also tend to change in the same direc-
tion (Bradley, 1989). Thus, assessing varied
aspects of a child’s family environment allows
prediction of the child’s IQ score.
Given this evidence, it is tempting to con-
clude that better-quality home environments
cause children to have higher IQ scores.
Whether that is actually the case, however, is
not yet known. The uncertainty reflects two
factors. First, the type of intellectual envi-
ronment that parents establish in the home
is almost certainly influenced by their genetic
TABLE 8.1
Sample Items and Subscales on the hOMe (Infant Version)
I. Emotional and Verbal Responsivity of Mother
1. Mother spontaneously vocalizes to child at least twice during visit (excluding scolding).
2. Mother responds to child’s vocalizations with a verbal response.
3. Mother tells child the name of some object during visit or says name of person or object in a
“teaching” style.
II. Avoidance of Restriction and Punishment
4. Mother does not shout at child during visit.
5. Mother does not express overt annoyance with or hostility toward child.
6. Mother does not interfere with child’s actions or restrict child’s movements more than three
times during visit.
III. Organization of Physical and Temporal Environment
7. When mother is away, care is provided by one of three regular substitutes.
8. Child is taken regularly to doctor’s office or clinic.
9. Child has a special place in which to keep his or her toys and “treasures.”
IV. Provision of Appropriate Play Materials
10. Child has push or pull toy.
11. Child has stroller or walker, kiddie car, scooter, or tricycle.
12. Provides learning equipment appropriate to age—cuddly toy or role-playing toys.
V. Maternal Involvement with Child
13. Mother tends to keep child within visual range and to look at him or her often.
14. Mother “talks” to child while doing her work.
15. Mother structures child’s play periods.
VI. Opportunities for Variety of Daily Stimulation
16. Mother reads stories at least three times weekly.
17. Child eats at least one meal per day with mother and father.
18. Child has three or more books of his or her own.
Source: Adapted from Bradley & Caldwell, 1984
Stimulating home environments, espe-
cially those in which adults and children
undertake challenging tasks together, are
associated with high IQ scores and high
achievement in school.
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312 n chapter 8 InTELLIGEnCE AnD ACADEmIC AChIEVEmEnT
makeup. Second, almost all studies using the HOME have focused on families in
which children live with their biological parents.
These two circumstances may mean that parents’ genes influence both the intel-
lectual quality of the home environment and children’s IQ scores; thus, the home in-
tellectual environment as such may not cause children to have higher or lower IQ.
Consistent with this possibility, in the few studies in which the HOME has been
used to study adoptive families, the correlations between it and children’s IQ scores
are lower than in studies of children living with their biological parents (Plomin,
Fulker et al., 1997). Thus, although scores on the HOME clearly correlate with chil-
dren’s IQ scores, whether causal relations exist between the two remains uncertain.
Shared and Nonshared Family environments The phrase “family intellectual
environment” is often taken to mean characteristics that are the same for all chil-
dren within the family: the parents’ emphasis on education, the number of books
in the house, the frequency of intellectual discussions around
the dinner table, and so on. As discussed in Chapter 3, how-
ever, each child within a given family also encounters unique,
nonshared environments. In any family, only one child can be
the firstborn and receive the intense, undivided parental at-
tention early in life that this status tends to bring. Similarly, a
child whose interests or personality characteristics mirror those
of one or both parents may receive more positive attention than
other children in the family. If homes that are extremely lack-
ing in intellectual stimulation are excluded from consideration,
such within-family variations in children’s environment may
have a greater impact on the development of intelligence than
do between-family variations (Petrill et al., 2004). In addition,
the influence of the nonshared environment increases with age,
and the influence of the shared environment decreases with
age, as children become increasingly able to choose their own
friends and activities (Bouchard, 2004; Segal et al., 2007).
The relative influence of shared environments and genetics
varies with family income. Among children and adolescents
from low-income families, the shared environment accounts
for more of the variance in IQ scores and academic achieve-
ment than genetics does. In contrast, among children and ado-
lescents from middle- and high-income families, the relative
influence of shared environment and genetics is reversed (Harden, Turkheimer, &
Loehlin, 2007; D. C. Rowe, Jacobson, & Van den Oord, 1999; Turkheimer et al.,
2003). These differing patterns are found as early as age 2 years (Tucker-Drob et
al., 2011). The reasons for the differences remain to be established.
Influences of Schooling
Attending school makes children smarter. One type of evidence for this conclu-
sion came from a study that examined IQ scores of older and younger Israeli chil-
dren within the 4th, 5th, and 6th grades (Cahan & Cohen, 1989). As indicated by
the gradual upward trends in the graphs in Figure 8.6, older children within each
grade did somewhat better than younger children within that grade on each part
of the test. However, the jumps in the graphs between grades indicate that chil-
dren who were only slightly older, but who had a year more schooling, did much
better than the slightly younger children in the grade below them. For example, on
With age, children increasingly shape their
own environments in ways that reflect their
personalities and tastes.
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the verbal-oddities subtest (which involves indicating which
word in a series does not belong with the others), the results
show a small gap between 123- and 124-month-old 4th-
graders but a large gap between both of them and 125-month-
old 5th-graders.
Another type of evidence indicating that going to school
makes children smarter is that average IQ and achievement
test scores rise during the school year but not during summer
vacation (Ceci, 1991; J. Huttenlocher, Levine, & Vevea, 1998).
The way in which these changes vary with children’s family
backgrounds adds further support to the view that schooling
makes children smarter. Children from families of low socio-
economic status and those from families of high socioeconomic
status make comparable gains in school achievement during
the school year. However, over the summer, the achievement
test scores of low-SES children tend to stay constant or drop, whereas the scores of
high-SES children tend to rise (K. L. Alexander, Entwisle, & Olson, 2007; Burkam
et al., 2004). The likely explanation is that during the academic year, schools pro-
vide children of all backgrounds with relatively stimulating intellectual environ-
ments, but when school is not in session, fewer children from low-SES families
have the kinds of experiences that allow them to build on what they learned to
increase their academic achievement.
Influence of Society
Intellectual development is influenced not only by charac-
teristics of children, their families, and their schools but also
by broader characteristics of the societies within which chil-
dren develop. One reflection of societal influences is that in
many countries throughout the world, average IQ scores have
consistently risen over the past 80 years, a phenomenon that
has been labeled the Flynn effect in honor of James Flynn,
the researcher who discovered this widespread trend (Flynn,
1987; 2009). In some countries, including the Netherlands
and Israel, average IQ scores have risen as much as 20 points;
in the United States, the gains have been roughly 10 points
(Dickens & Flynn, 2001; Flynn & Weiss, 2007). Given that
the gene pool has not changed appreciably over this period,
the increase in IQ scores must be due to changes in society.
The specific source of the Flynn effect remains controver-
sial. Some researchers argue that the key factors are improve-
ments in the lives of low-income families, such as improved
nutrition (Lynn, 2009), health (Eppig, Fincher, & Thornhill,
2010), and formal education (C. Blair et al., 2005), These researchers point to evi-
dence that the increase in IQ scores has been greatest among those in the lower
part of the IQ score and income distributions. For example, as shown in Figure
8.7, among Danes born from 1942 to 1980, there was no change in the scores of
people in the top 10% of the IQ distribution, but there was a large change among
those in the bottom 10% (Geary, 2005). IQ score changes in some other countries,
including Spain and Norway, show a similar pattern, but gains in yet other countries,
including the United States, France, and Britain, have been comparable throughout
the IQ score and income distributions (Nisbett et al., 2012). In the United States,
112 120 128 136 144112 120 128 136 144 112 120 128 136 144
1.00
.75
.50
.25
0
−.25
Age (in months)
Verbal oddities Word arithmetic problems
S
ta
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ar
di
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sc
or
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Grade 4 Grade 5 Grade 6
FIGURE 8.6 relations of age and grade
to performance on two parts of an IQ test
the jumps between grade levels indicate that
schooling exerts an effect on intelligence test
performance beyond that of the child’s age.
(Data from cahan & cohen, 1989)
1942 1947 1952 1957 1968 1980
60
50
40
30
20
10
0
IQ
T
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10th 90th
Year of Birth
FIGURE 8.7 changes in IQ score over
time among Danish adults with rela-
tively low IQ scores (10th percentile)
and relatively high IQ scores (90th per-
centile) as these data illustrate, IQ scores
have improved considerably over the years
among Danes near the bottom of the distri-
bution but have remained virtually constant
among people near the top. In the United
States, increases have been more uniform
throughout the IQ distribution. (adapted
from Geary et al., 2005)
Flynn effect n consistent rise in average
IQ scores that has occurred over the past
80 years in many countries

314 n chapter 8 InTELLIGEnCE AnD ACADEmIC AChIEVEmEnT
gains in intellectual achievement have occurred even in the top 5% of the popula-
tion (Wai, Putallaz, & Makel, 2012).
An alternative plausible explanation for the increases in IQ scores is increased
societal emphasis on abstract problem solving and reasoning (Flynn, 2009). Sup-
porting this interpretation is the fact that scores on tests of fluid intelligence, which
reflects abstract problem solving and reasoning, have increased much more than
scores on tests of crystallized intelligence (Nisbett et al., 2012). One source of these
recent increases in fluid intelligence might be experience with new technologies,
such as video games. Haier and colleagues (2009) found that 3 months of playing
a video game (Tetris) led to increased brain thickness in areas of adolescent girls’
brains that are specifically activated by playing the game and that are also active in
the types of spatial tasks that are often used to measure fluid intelligence.
One conclusion that sparks no controversy is that poverty hinders intellectual de-
velopment. In the following sections, we consider how poverty affects children’s de-
velopment in different societies, and how it contributes to differences in IQ scores
and school achievement among different racial and ethnic groups within the United
States. We will also consider risk factors associated with poverty that adversely affect
intelligence, as well as programs that enhance poor children’s intellectual development.
Effects of Poverty
The negative effects of poverty on children’s IQ scores are indisputable. Even after
taking into account the mother’s education, whether both parents live with the child,
and the child’s race, the adequacy of family income for meeting family needs is related
to children’s IQ scores (Duncan et al., 1998). Further, the more years children spend
in poverty, the lower their scores tend to be (Korenman, Miller, & Sjaastad, 1995).
Poverty exerts negative effects on intellectual development in numerous ways.
Chronic inadequate diet early in life can disrupt brain development; missing meals
on a given day (e.g., achievement test day) can impair intellectual functioning on
that day; reduced access to health services can result in greater numbers of absences
from school; conflicts between adults in the household can produce emotional tur-
moil that interferes with learning; insufficient intellectual stimulation can lead to
a lack of background knowledge needed to understand new material; and so on.
One source of evidence for the relation between poverty and IQ is the fact that
in all countries that have been studied, children from wealthier homes score higher
on IQ and achievement tests, on average, than do children from poorer homes
(Case, Griffin, & Kelley, 1999; Keating & Hertzman, 1999). More telling, in those
developed countries where the income gap between rich and poor is widest, such
as the United States, the difference between the intellectual achieve-
ment of children from rich and poor homes is much larger than in
countries in which the gap is smaller, such as the Scandinavian coun-
tries and, to a lesser degree, Germany, Canada, and Great Britain. As
shown in Figure 8.8, children from affluent families in the United
States score, on average, about the same on mathematics achievement
tests as children from affluent families in some comparison countries
with greater income equality. In contrast, children from poor families
in the United States have average achievement test scores far below
children from poor families in those same comparison countries. The
key difference is that poor families in the United States are much
poorer, relative to others in their society, than their counterparts in
many other developed countries. Thus, in 2011, 23% of children in
the United States lived in families with incomes below half that of
0 50 75 10025
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60
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Status of father’s occupation
U.S.
Japan
Canada
FIGURE 8.8 relation in three coun-
tries between fathers’ occupational status
and children’s math achievement U.S.
children whose fathers hold low-status
jobs perform, on average, far more poorly
on math-achievement tests than do chil-
dren whose fathers hold comparable jobs in
canada or Japan. In contrast, U.S. children
whose fathers have high-status jobs per-
form, on average, as well as children whose
fathers have comparable jobs in canada
and almost as well as children from similar
backgrounds in Japan. (Data from case et
al., 1999)

G E n E S , E n V I R O n m E n T , A n D T h E D E V E L O P m E n T O f I n T E L L I G E n C E n 315
the median U.S. family income. By contrast, in a set of 35 other developed coun-
tries, only 11% of children were from families with this low a percentage of the
median income in their country (UNICEF, 2012).
As noted in Chapter 1, within the United States, the percentage of children
living in poor families is much higher among Hispanic Americans and African
Americans than among European Americans and Asian Americans and is much
higher in families headed by a single female than in families headed by a married
couple. These economic differences help explain the group differences in IQ scores
that we examine in the next section.
Race, Ethnicity, and Intelligence
Few claims stir stronger passions than those surrounding assertions that racial and
ethnic groups differ in intelligence. It is therefore especially important to know
both the facts about this issue and what can and cannot be concluded from them.
One fact is that the average IQ scores of children from different racial and eth-
nic groups do differ. For example, the average IQ score of European American chil-
dren is about 10 points higher than that of African American children (Dickens &
Flynn, 2006). The average scores of Hispanic American and Native American chil-
dren are a few points higher than those of African American children, and those of
Asian American children are a few points higher than those of European Americans
(Nisbett et al., 2012). These differences are explained in part by differences in social-
class backgrounds. Within each social class, however, differences in mean IQ scores
of African American and European American children also are present, though they
are smaller than those that are present when social class is not held constant (L. A.
Suzuki & Valencia, 1997).
A second fact is that scientific statements about group differences in IQ scores
refer to statistical averages rather than to any individual’s score. Understanding
this second fact is essential for interpreting the first. Millions of African American
children have IQ scores higher than the average European American child, and
millions of European American children have IQ scores lower than the average
African American child. Far more variability exists within each racial group than
between them. Thus, data on the average IQ score of members of an ethnic or racial
group tell us nothing about a given individual.
A third crucial fact is that differences in IQ and achievement test scores of chil-
dren from different racial and ethnic groups describe children’s performance only in
the environments in which the children live. The findings do not indicate their intel-
lectual potential, nor do they indicate what their scores would be if the children lived
in different environments. Indeed, with decreases in discrimination and inequality
in the past 40 years, achievement test differences between European American and
African American children decreased considerably. A rigorous analysis of changes
over time in intelligence test scores showed that African American schoolchildren
reduced the gap with European American schoolchildren by 4 to 7 points between
1972 and 2002 (Dickens & Flynn, 2006); achievement test scores have shown the
same trend (N. Brody, 1992).
Risk Factors and Intellectual Development
In the popular media, reports on how to help all children reach their intellectual
potential often focus on a single factor—the need to eliminate poverty or the need
to eliminate racism or the need to preserve two-parent families, or the need for
high-quality day care, or the need for universal preschool education, and so on.

316 n chapter 8 InTELLIGEnCE AnD ACADEmIC AChIEVEmEnT
However, no single factor, nor even any small group of fac-
tors, is the key. Instead, a variety of factors in combination
contribute to the problem of poor intellectual development.
To capture the impact of these multiple influences,
Arnold Sameroff and his colleagues developed an envi-
ronmental risk scale (Sameroff et al., 1993) based on 10 fea-
tures of the environment that put children at risk for low IQ
scores (Table 8.2). Each child’s risk score is a simple count
of the number of major risks facing the child. Thus, a child
growing up with, say, a mother who is unemployed, unmar-
ried, highly anxious, and mentally ill would have an environ-
mental risk score of 4.
Sameroff and his colleagues measured the IQ scores and
environmental risks of more than 100 children when they
were 4-year-olds and again when they were 13-year-olds.
They found that the more risks in a child’s environment, the
lower the child’s IQ score tended to be. As shown in Figure
8.9, the effect was large. The average IQ score of children
whose environments did not include any of the risk factors
was around 115; the average score of children whose envi-
ronments included six or more risks was around 85. The
sheer number of risks in the child’s environment was a bet-
ter predictor of the child’s IQ score than was the presence
of any particular risk. Subsequent studies demonstrated
similarly strong relations between the number of risk fac-
tors and school grades (Gassman-Pines & Yoshikawa, 2006;
Gutman, Sameroff, & Cole, 2003).
The Sameroff (1993) study also provided an interest-
ing perspective on why children’s IQ scores are highly sta-
ble. It is not just that children’s genes remain constant; over
time, their environment tends to remain fairly constant as
well. The study revealed that there was just as much stabil-
ity in the number of risk factors in children’s environments
at ages 4 and 13 years as there was in their IQ scores over
that period.
The number of risk factors in a 4-year-old’s environment not only correlates
highly with the child’s IQ score at age 4 but also predicts likely changes in the
child’s score between ages 4 and 13. That is, if two children have the same IQ score
at age 4 but one child lives in an environment with more risk factors, the child fac-
ing more risks will, at age 13, probably have an IQ score lower than that of the
other child. Thus, environmental risks seem to have both immediate and long-term
effects on children’s intellectual development. Genetic contributions cannot be
ruled out—anxiety, poor mental health, and other risk factors may be biologically
transmitted from parent to child—but a greater number of risk factors is definitely
associated with lower IQ scores.
Although Sameroff and his colleagues described their measure as a “risk index,”
it is as much a measure of the quality of a child’s environment as of its potential for
harm. High IQ scores are associated with favorable environments as much as low
scores are associated with adverse ones. This is true for children from low-income
families as well as for children in general. Low-income parents who, relative to
others with similar incomes, are responsive to their children and provide them with
TABLE 8.2
risk Factors related to IQ Scores
1. Head of household unemployed or working in low-status occupation
2. Mother did not complete high school
3. At least four children in family
4. No father or stepfather in home
5. African American family
6. Large number of stressful life events in past few years
7. Rigidity of parents’ beliefs about child development
8. Maternal anxiety
9. Maternal mental health
10. Negative mother–child interactions
Source: Sameroff et al., 1993
Number of risks
65 7ñ843210
70
80
90
100
110
120
IQ
4-year-olds
13-year-olds
FIGURE 8.9 risk factors and IQ score
For both younger and older children, the
more risk factors in the environment, the
lower the average IQ score. (Data from Sam-
eroff et al., 1993)

G E n E S , E n V I R O n m E n T , A n D T h E D E V E L O P m E n T O f I n T E L L I G E n C E n 317
safe play areas and varied learning materials have children with higher IQ scores
(Bradley et al., 1994). Thus, high-quality parenting can help alleviate the risks
imposed by poverty.
Programs for Helping Poor Children
During the early 1960s, a political consensus developed in the United States that
helping children from poor families was an urgent national priority. Psychological
research contributed to this consensus by demonstrating that children’s environ-
ments had significant effects on their cognitive growth (W. Dennis & Najarian,
1957; J. M. Hunt, 1961). As a consequence, over the next decade, many interven-
tion programs were initiated to enhance the intellectual development of preschool-
ers from impoverished families.
In a comprehensive analysis of 11 of the most prominent early-intervention
programs—all of which focused on 2- to 5-year-old African American children
from low-income families—Irving Lazar and his colleagues found a consistent pat-
tern (Lazar et al., 1982). Participation in the programs, most of which lasted a year
or two, initially increased children’s IQ scores substantially—by 10 to 15 points.
However, over the next 2 or 3 years, the gains decreased, and by the 4th year after
the end of the programs, no differences were apparent between the IQ scores of
participants and those of nonparticipants from the same neighborhoods and back-
grounds. Similar patterns emerged in an analysis of programs that emphasized
mathematics and reading achievement (McKey et al., 1985).
Fortunately, other effects of these experimental programs were more enduring.
Only half as many program participants as nonparticipants were later assigned to
special-education classes—14% versus 29%. Similarly, fewer participants were held
back in school, more participants subsequently graduated from high school, and
fewer had been arrested by age 18 (Reynolds et al., 2001).
This combination of findings may seem puzzling. If the intervention programs
did not result in lasting increases in IQ or achievement test scores, why would they
have led to fewer children being assigned to special-education classes or being
held back in school? A likely reason is that the interventions had long-term effects
on children’s motivation and behavior. These effects would help children do well
enough in the classroom to be promoted with their classmates, which in turn might
make them less likely to drop out of high school and less likely to turn to criminal
activity, even if their IQ scores were unchanged.
Participation also led to benefits after children finished school.
As adults, former participants in some of the programs used the
welfare system less and earned larger salaries than did nonpar-
ticipants (Haskins, 1989; McLoyd, 1998). Positive effects such as
these suggest that early-intervention programs not only can help
participants lead more successful lives but might also more than
repay their costs by reducing the need for social services. As dis-
cussed in Box 8.2, at least one specialized, intensive program has
shown the possibility of producing enduring gains in IQ score
and school achievement as well.
project head Start In response to the same political consensus
of the 1960s that led to small-scale early-intervention programs,
the U.S. government initiated a large-scale intervention program:
Project Head Start. In the past 50 years, this program has pro-
vided a wide range of services to more than 25 million children.
children who participate in head Start pro-
grams, like the youngsters pictured here, are
in later years less likely to be held back in
the same grade and more likely to graduate
from high school than are children from sim-
ilar backgrounds who do not participate in
these programs.
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At present, Head Start serves more than 900,000 preschoolers per year, most
of them 4-year-olds. The population served is racially and ethnically diverse: in
2010, 39% were African Americans, 31% European Americans, and 34% Hispanic
Americans (the sum is more than 100% because small percentages of children
were counted in multiple categories) (Schmit, 2011). Almost all children in Head
Start are from families with incomes below the poverty line, mostly single-parent
families. In the program, children receive medical and dental care and nutritious
meals, and are provided with a safe environment. Many parents of participating
children work as caregivers at the Head Start centers, serve on policy councils that
help plan each center’s directions, and receive help with their own vocational and
emotional needs.
Consistent with the findings of the smaller experimental intervention programs
that have been aimed at 3- and 4-year-olds, participation in Head Start produces
higher IQ and achievement test scores at the end of the program and briefly thereafter.
The strongest evidence for this conclusion comes from the Head Start Impact Study
(U.S. Department of Health and Human Services, 2010), an especially well-done
The difficulty of producing enduring gains
in poor children’s IQ and achievement test
scores led some evaluators to conclude that
intelligence is unalterable (A. R. Jensen,
1973; Westinghouse Learning Corporation,
1969). However, the same findings motivated
other researchers to find out if interventions
that started in infancy, continued for a num-
ber of years, and attempted to improve many
aspects of children’s lives might produce
enduring increases in IQ, even though briefer,
less intensive, later-starting efforts had not.
One intervention that has yielded a positive
answer to these questions is the Carolina
Abecedarian Project, a program that clearly
illustrates the theme of how research can
improve children’s welfare (F. A. Campbell &
Ramey, 2007; Ramey & Ramey, 2004).
Children were selected to participate in
the Abecedarian (pronounced “a-bee-cee-
darian”) program on the basis of low family
income, the absence of a father in the home,
low maternal IQ score and education, and
other factors that put the children at risk for
developmental problems. More than 95% of
the children who participated were African
American. The program was based on seven
principles (Ramey & Ramey, 2004):
1. Encourage exploration.
2. Mentor basic skills.
3. Celebrate developmental advances.
4. Rehearse and generalize new skills.
5. Protect children from inappropriate dis-
approval, teasing, and punishment.
6. Communicate richly and responsively.
7. Guide and limit behavior.
Children in the program began attending a
special day-care center by the time they were
6-month-olds and continued to do so through
the age of 5 years. They were at the center
for the entire working day (7:45 A.M. to 5:30
P.M.), 5 days per week, 50 weeks per year, for
5 years. The teacher–child ratio was optimal:
1:3 for children aged 3 years and younger
and 1:6 for 4- and 5-year-olds. Children
aged 3 years and younger received a program
that emphasized general social, cognitive,
and motor development; for 4- and 5-year-
olds, the program also provided systematic
instruction in math, science, reading, and
music. At all ages, the program emphasized
language development and ensured exten-
sive verbal communication between teachers
and children. Program personnel also worked
with the children’s mothers outside the day-
care center to improve their understanding
of child development. Families of children
in the experimental program were provided
with nutritional supplements and access to
high-quality health care. Families of children
in a control group received similar nutritional
and health benefits, but the children did not
attend the day-care center.
This well-planned, multifaceted program
proved to have lasting positive effects on the
IQ scores and achievement levels of chil-
dren in the experimental group. At the age
of 21 years, 15 years after the program had
ended, these children had mean IQ scores 5
points higher than the children in the con-
trol group: 90 versus 85 (F. A. Campbell et
al., 2001). Participants’ achievement test
scores in math and reading were also higher.
As with less encompassing intervention pro-
grams, fewer participants were ever held
back in school or placed in special-educa-
tion classes. At age 30, a higher percentage
of children in the experimental group than
in the control group had graduated from
college: 23% versus 6% (F. A. Campbell
et al., 2012). A replication of the program
demonstrated that the lower the mother’s
BOX 8.2: applications
A HIGHLY SUCCESSFUL EARLY INTERVENTION:
THE CAROLINA ABECEDARIAN PROJECT
Carolina Abecedarian Project n com-
prehensive and successful enrichment
program for children from low-income
families

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experiment that included 5000 3- and 4-year-olds from low-income families who
were on waiting lists to participate in a Head Start program. Half the children were
randomly assigned to participate in Head Start; the other half followed another path
of their parents’ choosing. The children comprised a nationally representative sam-
ple of the low-income population, and the Head Start centers in which the children
enrolled were representative in terms of their quality.
The children who participated in Head Start showed better prereading and pre-
writing skills (though no better math skills) at the end of a year in the program (U.S.
Department of Health and Human Services, 2005). By the end of 1st grade, how-
ever, children’s intellectual outcomes were almost identical to those of nonparticipants
(U.S. Department of Health and Human Services, 2010). Less extensive evaluations
of Head Start have obtained similar findings (McKey et al., 1985; McLoyd, 1998).
On the other hand, participation in Head Start produces a number of other
positive effects that do endure, ones that resemble those produced by the experi-
mental preschool programs: improved social skills and health, lower frequency of
being held back in school, greater likelihood of graduating from high school and
educational level, the greater the difference
the program made (Ramey & Ramey, 2004).
What lessons can be drawn from the
Abecedarian Project? One important lesson
is the benefit of starting interventions early
and continuing them for substantial periods.
A version of the Abecedarian program that
ended at age 3 did not produce long-term
effects on intelligence, nor did a program
that provided educational support from kin-
dergarten through 2nd grade (Burchinal et
al., 1997; Ramey et al., 2000). A second
crucial lesson is the need for caregivers to
interact with infants in positive, responsive
ways. High adult-to-infant ratios in day-care
centers make such interactions more likely,
as does educating staff members in the
need for such interactions. A third lesson
is that the gains produced by this and other
successful early-intervention programs are
likely due at least as much to improvements
in children’s self-control and perseverance
as to changes in their IQ scores (Heckman,
2011; Knudsen et al., 2006). Probably the
most important lesson is the most basic: it
is possible to design interventions that have
substantial, lasting, positive effects on poor
children’s intellectual development.
2018 22161412108
80
85
90
95
100
105
M
at
h
S
co
re
s
Math Achievement Score (normalized)
ControlTreatment
the benefits of participating in the abecedarian project remained evident 15 years
after the end of the program, as illustrated in this graph of the mathematics achieve-
ment of children who participated either in the program or in the control condition. rel-
ative to the average level of mathematics achievement of children in the United States,
performance of both groups of children declined somewhat between ages 8 and 21, but
at all ages, children who participated in the program performed better than did children
from comparably disadvantaged backgrounds who had been in the control condition.

320 n chapter 8 InTELLIGEnCE AnD ACADEmIC AChIEVEmEnT
enrolling in college, and lower rates of drug use and delinquency (Love, Chazan-
Cohen, & Raikes, 2007; Zigler & Styfco, 2004). These important gains have con-
tributed to the enduring popularity of Head Start.
review:
The development of intelligence is influenced by qualities of the child, the immediate
environment, and the broader society. The child’s genetic inheritance exerts a large influ-
ence, especially for children from middle- and upper-income families; this influence steadily
increases over the course of development. The intellectual environment provided by the
child’s family and the schooling the child encounters are also influential, as are the family’s
economic status and educational level and whether one or two parents are present. For chil-
dren from low-income backgrounds, these shared aspects of the environment exert a stron-
ger influence than do children’s genes on differences in their intellectual development. The
impact of society is evident in the Flynn effect, which reflects the consistent rise in IQ scores
in all economically advanced countries.
Programs such as Project Head Start are often beneficial in a variety of ways, though their
effect on IQ and achievement test scores usually fades over time. However, at least one early-
intervention program, the Abecedarian Project, reports enduring positive effects on IQ scores
and achievement.
Alternative Perspectives on Intelligence
The discussions of intellectual development in this chapter have relied on IQ tests
as their main measure. Research using these tests has revealed a great deal about
the development of intelligence. However, a number of contemporary theorists
have noted that many important aspects of intelligence are not measured by IQ
tests. The tests assess verbal, mathematical, and spatial capabilities, but they do not
directly examine other abilities that seem to be inherent parts of intelligence: cre-
ativity, social understanding, knowledge of one’s own strengths and weaknesses, and
so on. This perspective has led Howard Gardner and Robert Sternberg to formu-
late theories of intelligence that encompass a wider range of human abilities than
do traditional theories.
Howard Gardner (1993) labeled his approach multiple intelligences theory.
Its basic claim is that people possess eight kinds of intelligence: the linguistic,
among the benefits of head Start is the pro-
vision of nutritious meals for children who
otherwise might be at risk for malnutrition.
m
A
R
K
R
IC
h
A
R
D
S
/
P
h
O
T
O
E
D
IT
multiple intelligences theory n
Gardner’s theory of intellect, based on the
view that people possess at least eight
types of intelligence

A L T E R n A T I V E P E R S P E C T I V E S O n I n T E L L I G E n C E n 321
logical-mathematical, and spatial abilities emphasized in previous theories and
measured on IQ tests, and also musical, naturalistic, bodily-kinesthetic, intraper-
sonal, and interpersonal abilities (see Table 8.3).
Gardner used several types of evidence to arrive at this set of intelligences. One
involved deficits shown by people with brain damage. For example, some brain-
damaged patients function well in most respects but have no understanding of
other people (Damasio, 1999). This phenomenon suggested to Gardner that inter-
personal intelligence was distinct from other types of intelligence. A second type of
evidence that Gardner used to identify this set of intelligences was the existence of
prodigies, people who from early in life show exceptional ability in one area but not
in others. One such example is Wolfgang Amadeus Mozart, who displayed musical
genius while still a child but was unexceptional in many other ways. The existence
of highly specialized musical talents such as Mozart’s provides evidence for viewing
musical ability as a separate intelligence. Although Gardner’s theory of multiple in-
telligences is backed by less supporting evidence than traditional theories of intel-
ligence, its optimistic message—that children have a variety of strengths on which
parents and teachers can build—has led to its having a large influence on education.
Robert Sternberg (1999) also argued that the emphasis of IQ tests on the type
of intelligence needed to succeed in school is too narrow. However, the alterna-
tive view of intelligence that he proposed differs from that proposed by Gardner.
Sternberg’s theory of successful intelligence envisions intelligence as “the ability
to achieve success in life, given one’s personal standards, within one’s sociocultural
context” (p. 4). In his view, success in life reflects people’s ability to build on their
strengths, to compensate for their weaknesses, and to select environments in which
they can succeed. When people choose a job, for instance, their understanding of
the conditions that will motivate them may be crucial to their success.
Sternberg proposed that success in life depends on three types of abilities: ana-
lytic, practical, and creative. Analytic abilities involve the linguistic, mathematical,
and spatial skills that are measured by traditional intelligence tests. Practical abilities
theory of successful intelligence n
Sternberg’s theory of intellect, based on
the view that intelligence is the ability to
achieve success in life
TABLE 8.3
Gardner’s theory of Multiple Intelligences
Type of Intelligence Description Examples
Linguistic intelligence Sensitivity to the meanings and sounds of words; mastery of syntax; appreciation of the
ways language can be used
Poet, political speaker, teacher
Logical-mathematical
intelligence
Understanding of objects and symbols, of the actions that can be performed on them,
and of the relations between these actions; ability for abstraction; ability to identify
problems and seek explanations
Mathematician, scientist
Spatial intelligence Capacity to perceive the visual world accurately, to perform transformations upon
perceptions, and to re-create aspects of visual experience in the absence of physical
stimuli; sensitivity to tension, balance, and composition; ability to detect similar patterns
Artist, engineer, chess master
Musical intelligence Sensitivity to individual tones and phrases of music; an understanding of ways to
combine tones and phrases into larger musical rhythms and structures; awareness of
emotional aspects of music
Musician, composer
Naturalistic intelligence Sensitivity to, and understanding of, plants, animals, and other aspects of nature Biologist, farmer, conservationist
Bodily-kinesthetic
intelligence
Use of one’s body in highly skilled ways for expressive or goal-directed purposes; capacity
to handle objects skillfully
Dancer, athlete, actor
Intrapersonal intelligence Access to one’s own feeling life; ability to draw on one’s emotions to guide and
understand one’s behavior
Novelist, therapist, parent
Interpersonal intelligence Ability to notice and make distinctions among the moods, temperaments, motivations, and
intentions of other people and potentially to act on this knowledge
Political leader, religious leader,
parent, teacher, therapist
Source: H. Gardner, 1993
Mozart’s musical genius was evident from
early in childhood, leading some of the
greatest musicians of his day to play music
with him when he was still a child.
C
O
R
B
IS

322 n chapter 8 InTELLIGEnCE AnD ACADEmIC AChIEVEmEnT
involve reasoning about everyday problems, such as how to resolve conflicts with
other people. Creative abilities involve intellectual flexibility and innovation that
allow adaptation to novel circumstances.
The theories proposed by Gardner and Sternberg have inspired a rethinking of
long-held assumptions about intelligence. Intelligence and success in life clearly
involve a broader range of capabilities than traditional intelligence tests measure,
and measuring these broader capabilities may allow a more encompassing assess-
ment of intelligence. There is not now, nor will there ever be, a single correct theory
of intelligence, nor a single best measure of it. What is possible is a variety of theo-
ries, and tests based on them, that together reveal the varied ways in which people
can be intelligent.
review:
Howard Gardner and Robert Sternberg have formulated novel theories of intelligence.
Gardner’s multiple intelligences theory proposes that there are eight intelligences: linguis-
tic, logical-mathematical, spatial, musical, naturalistic, bodily-kinesthetic, intrapersonal,
and interpersonal. Sternberg’s theory of successful intelligence proposes that success in life
depends on three types of abilities: analytic, practical, and creative. Both theories conceive
of intelligence as a broader set of abilities than those included in traditional theories.
Acquisition of Academic Skills: Reading,
Writing, and Mathematics
One important goal to which children apply their intelligence is learning the skills
and concepts taught at school. Because these skills and concepts are necessary for
normal intellectual development in modern societies, because they are central to
success in adulthood, and because they can be difficult to master, children spend
more than 2000 days in school from 1st through 12th grade. Much of this time is
devoted to acquiring proficiency in reading, writing, and mathematics. In this sec-
tion, we focus on how children learn these skills, why some children have such dif-
ficulty mastering them, and how children’s learning can be improved.
Reading
Many children learn to read effortlessly, but others do not. You can no doubt
remember the painful times classmates—and perhaps you, yourself—seemed to
take forever to read aloud simple sentences, even in 2nd and 3rd grade. Why is it
that some children learn to read so easily, whereas others experience great difficulty
and frustration? To answer this question, we must examine the typical path of read-
ing development as well as how and why children deviate from it.
Chall (1979) described five stages of reading development. These stages provide
a good overview of the typical path to mastery:
1. Stage 0 (birth until the beginning of 1st grade): During this time, many chil-
dren acquire key prerequisites for reading. These include knowing the letters
of the alphabet and gaining phonemic awareness, that is, knowledge of the
individual sounds within words.
2. Stage 1 (1st and 2nd grades): Children acquire phonological recoding skills,
the ability to translate letters into sounds and to blend the sounds into words
(informally referred to as “sounding out”).
phonemic awareness n ability to iden-
tify component sounds within words
phonological recoding skills n ability
to translate letters into sounds and to
blend sounds into words; informally
called sounding out

A C Q U I S I T I O n O f A C A D E m I C S K I L L S : R E A D I n G , W R I T I n G , A n D m A T h E m A T I C S n 323
3. Stage 2 (2nd and 3rd grades): Children gain fluency in reading simple
material.
4. Stage 3 (4th through 8th grades): Children become able to acquire reason-
ably complex, new information from written text. To quote Chall, “In the pri-
mary grades, children learn to read; in the higher grades, they read to learn”
(1979, p. 24).
5. Stage 4 (8th through 12th grades): Adolescents acquire skill not only in
understanding information presented from a single perspective but also in
coordinating multiple perspectives. This ability enables them to appreciate
the subtleties in sophisticated novels and plays, which almost always include
multiple viewpoints.
This description of developmental stages provides a general sense of the reading
acquisition process and a framework for understanding how particular develop-
ments fit into the broader picture.
Prereading Skills
Preschoolers acquire certain basic information about reading just from looking at
books and having their parents read to them. They learn that (in English and other
European languages) text is read from left to right; that after they reach the right
end of a line, the text continues at the extreme left of the line below; and that words
are separated by small spaces.
Children with well-educated parents also tend to learn the names of most or
all the letters of the alphabet before they enter school. This tends not to be true
of children whose parents are poorly educated. In one study of beginning kinder-
gartners, 86% of children whose mothers graduated from college were proficient in
letter recognition, but only 38% of children whose mothers did not complete high
school were ( J. West, Denton, & Germino-Hausken, 2000).
Kindergartners’ mastery of letter names is positively correlated with their later
reading achievement through at least 7th grade (Vellutino & Scanlon, 1987). How-
ever, no causal relation exists between the two: teaching the names of the letters to
randomly chosen preschoolers does not increase their subsequent reading achieve-
ment (Piasta & Wagner, 2010). Instead, it appears that other variables, such as chil-
dren’s interest in books and parents’ interest in their children’s reading, stimulate
both early knowledge of the alphabet and later high reading achievement.
Phonemic awareness, on the other hand, is both correlated with later reading
achievement and a cause of it. To measure awareness of the component sounds
within words, researchers ask children to decide whether two words start with the
same sound, to identify component sounds within a word, and to indicate what
would remain if a given sound were removed from a word. Kindergartners’ perfor-
mance on these measures of phonemic awareness is the strongest predictor of their
ability to sound out and spell words in the early grades—stronger even than IQ
score or social-class background (Nation, 2008; Rayner et al., 2001)—and it contin-
ues to be related to reading achievement as much as 11 years later, above and beyond
the influence of the child’s social-class background (MacDonald & Cornwall, 1995).
Even more impressive, a review of 52 well-controlled experimental studies
indicated that teaching phonemic-awareness skills to 4- and 5-year-olds causes
them to become better readers and spellers, with the effects enduring for years
after the training (National Reading Panel, 2000). Instructing young children to
break words into their component sounds and then writing the letter that best
matches each successive sound causes especially large gains in spelling (Levin
& Aram, 2013).

324 n chapter 8 InTELLIGEnCE AnD ACADEmIC AChIEVEmEnT
Although explicit training can help foster phonemic awareness, most children
do not receive such training. Where, then, does phonemic awareness come from
in the natural environment? One relevant experience is hearing nursery rhymes.
Many nursery rhymes highlight the contribution of individual sounds to differ-
ences among words (e.g., “I do not like green eggs and ham; I do not like them,
Sam I am.”) Consistent with this hypothesis, 3-year-olds’ knowledge of nursery
rhymes correlates positively with their later phonemic awareness, above and beyond
their IQ scores and their mother’s educational level (Maclean, Bryant, & Bradley,
1987). Other factors that contribute to the development of phonemic awareness
include growth of working memory, increasingly efficient processing of language,
and, especially, reading itself (Anthony & Francis, 2005; McBride-Chang, 2004).
Children with greater phonemic awareness read more and read better, which, in
turn, leads to further increases in their phonemic awareness and in the quantity and
quality of their reading.
Word Identification
Rapid, effortless word identification is crucial not only to reading comprehension but
also to its enjoyment. One remarkable finding makes the point: 40% of 4th-graders
who were poor at identifying words said they would rather clean their rooms than
read ( Juel, 1988). One child went as far as to volunteer, “I’d rather clean the mold
around the bathtub than read.” Thus, not only does poor word identification make
the reading process slow and laborious, it also leads children to read no more than
is absolutely necessary, which, in turn, hinders improvement in their reading skills.
Words can be identified in two main ways: phonological recoding and visually
based retrieval. As previously indicated, phonological recoding involves converting
the visual form of a word into a verbal, speechlike form and using the speechlike
form to determine the word’s meaning. Visually based retrieval involves process-
ing a word’s meaning directly from its visual form.
Most young children use both approaches (Share, 2004), choosing adaptively
between them from 1st grade onward. They do so through a strategy–choice
process, in which they choose the fastest approach that is likely to allow correct
word identification. In the context of reading, this means that on easy words, chil-
dren rely heavily on the fast but not always accurate approach of visually based
retrieval; on hard words, they resort to the slower but surer strategy of phonological
recoding. As shown in Figure 8.10, 1st-graders are very skillful in adjusting their
strategies to the difficulty of a particular word.
The mechanisms underlying this adaptive strategy choice involve a form of
associative learning in which children’s past behavior shapes their future behavior
(Siegler, 1996). Beginning readers rely heavily on phonological recoding, because
the associations between words’ visual forms and their sounds are too weak to allow
much use of retrieval. Correct use of phonological recoding increases the associa-
tions between words’ visual forms and their sounds, which in turn allows greater
use of visually based retrieval. Consistent with this view, the shift to retrieval occurs
most rapidly for words on which children most often execute phonological recod-
ing correctly—words that are short, that have regular letter–sound relations, and
that children encounter frequently. Also consistent with this view, children who are
better at phonological recoding stop using that approach earlier, because their past
success with it enables them to shift more rapidly to visually based retrieval. A third
correct implication is that reading instruction that emphasizes phonics, and the
strategy of phonological recoding, should help to produce fast and accurate word
identification (M. J. Adams, Treiman, & Pressley, 1998; Xue & Meisels, 2004).
the appeal of nursery rhymes to young chil-
dren has always been obvious, but only
recently have the benefits of such rhymes
for phonemic awareness and reading acqui-
sition become known.
JO
h
n
n
Y
C
R
A
W
f
O
R
D
/
T
h
E
I
m
A
G
E
W
O
R
K
S
visually based retrieval n proceeding
directly from the visual form of a word to
its meaning
strategy–choice process n procedure
for selecting among alternative ways of
solving problems

A C Q U I S I T I O n O f A C A D E m I C S K I L L S : R E A D I n G , W R I T I n G , A n D m A T h E m A T I C S n 325
With age and experience, vocabulary knowledge becomes an increasingly impor-
tant influence on word identification, particularly on words with irregular sound–
symbol correspondences (Nation, 2008). However, phonological recoding skill also
continues to be important, even for adults when they encounter unfamiliar words.
Box 8.3 discusses the relation between poor phonological recoding skills and the
reading disability known as dyslexia.
Comprehension
The point of learning to read individual words is to comprehend the text in which
the words appear. Reading comprehension involves forming a mental model
to represent the situation or idea being depicted in the text and continuously
updating it as new information appears (Oakhill & Cain, 2000). All the types of
mental operations that influence cognitive development in general—basic pro-
cesses, strategies, metacognition (knowledge about people’s thinking), and content
knowledge—also influence the development of reading comprehension.
Basic processes such as encoding (identification of key features of an object or
event) and automatization (executing a process with minimal demands on cogni-
tive resources) are crucial to reading comprehension. The reason is simple: children
who are able to identify the key features of stories will understand the story better,
and children who are able to automatically identify the key features of words will
have more cognitive resources left to devote to comprehension. Fast, accurate word
identification correlates positively with reading comprehension at all points from
the 1st grade through adulthood (Cunningham & Stanovich, 1997).
10
Percent overt strategy use
20
Dig
House
People
Horse
Mother
Here
Play
Kitten
FindBook
Ran
Eight
Little Hat Ten
Baby
Pet
Paper
Hand
Ride
Apples
Now Cookie
White
Thumb
Cherries
Perform
Parade
Father
Pair
ShellsPurple
Duck
Sandwich
Foot
Shop
Saw
Cake
Bat
Game
Put
Eating
Wig
Pie
SitShe, All
Them
Puppy
Seven
Do
Black
We
Three
Fish
Like
BlueGreen
Dog Five Sun
Not BedGot
Her
It
Can
Then
Bird
Brown
At
Red
Nine
Up
Big
Pig
Car
Two
One
Four
Man
ToBoxAnd
Orange
Fox
Cat
In
Yellow
The Girl
On
You
BoySix
Look
Zoo
Over
30 40 50 60 70 80 90
90
80
70
60
50
40
30
20
10
0
P
er
ce
n
t
er
ro
rs
Reading
r = .86
Your
FIGURE 8.10 Young children’s strategy
choices in reading a strong positive cor-
relation exists between the difficulty of a
word, as defined by the percentage of errors
children make on it, and the frequency of
young children’s use of an overt strategy,
such as audible phonological recoding, to
read it. thus, on words that 1st-graders find
easy, such as “in,” they generally retrieve
the word’s pronunciation, but on words
they find difficult, such as “parade,” they
often fall back on overt strategies such as
sounding out. (Siegler, 1986)
mental model n cognitive processes
used to represent a situation or sequence
of events

326 n chapter 8 InTELLIGEnCE AnD ACADEmIC AChIEVEmEnT
Some children of normal intelligence whose
parents encourage reading nonetheless read
very poorly. Such poor reading despite nor-
mal intelligence is referred to as dyslexia
and affects 5% to 10% of children in the
United States (Anthony & Francis, 2005).
The causes of dyslexia are not well under-
stood, but genetics are clearly part of the
story. If one of a pair of monozygotic twins
is diagnosed as dyslexic, the probability of
the other twin receiving a similar diagnosis
is 84%, whereas if the twins are dizygotic,
the corresponding probability is 48% (Kovas
& Plomin, 2007; Oliver et al., 2004). The
extent of genetic influences varies with pa-
rental educational level: as with IQ score,
genetic influences on dyslexia are larger
with children of highly educated parents
than with children of less educated parents
(Friend, DeFries, & Olson, 2008).
At a cognitive level of analysis, dyslexia
stems primarily from weak ability to dis-
criminate between phonemes, from poor
short-term memory for verbal material
(as indicated, for example, by poor abil-
ity to recall an arbitrary list of words), and
from slow recall of the names of objects
(Vellutino, Scanlon, & Spearing, 1995;
Wimmer, Mayringer, & Raberger, 1999).
Determining the sounds that go with vow-
els is especially difficult for children with
dyslexia, at least in English, where a sin-
gle vowel can be pronounced in many
ways (consider the sounds that accompany
the letter “a” in “ha,” “hat,” “hall,” and
“hate.” “Because of these weaknesses,
dyslexic children have great difficulty mas-
tering the letter–sound correspondences
used in phonological recoding, especially in
languages, such as English, with irregular
sound–symbol correspondences (Sprenger-
Charolles, 2004).
For instance, as shown in the figure, when
asked to read pseudowords such as parding,
dyslexic 13- and 14-year-olds perform at
the same level as typical 7- and 8-year-olds
(Siegel, 1993). As would be expected from
the strategy–choice model described on
page 324, this difficulty with phono-
logical processing causes most dys-
lexic children to be poor at visually
based retrieval, as well as at sound-
ing out words (Manis et al., 1996).
The problem can be a lasting one:
most individuals who have poor pho-
nological processing skills in early
elementary school remain poor read-
ers as adults (Wagner et al., 1997).
This is especially the case for chil-
dren who are from disadvantaged
backgrounds and who attend inferior
schools: children with dyslexia who
come from more advantaged family
backgrounds and who attend better
schools are more likely to show sub-
stantial improvements (S. E. Shay-
witz, Mody, & Shaywitz, 2006).
Studies of brain functioning sup-
port the view that poor phonological
processing is at the heart of dys-
lexia. When dyslexic children read,
two areas of their brains are less ac-
tive than the corresponding areas in
typical children reading the same
words (Schlaggar & Church, 2009;
Tanaka et al., 2011). One such area
is directly involved in discriminating
phonemes; the other area is involved
in integrating visual and auditory
data (in this case, integrating let-
ters on the page with accompanying
sounds).
How can dyslexic children be
helped? One tempting idea is that
because these children have dif-
ficulty learning phonics, they would learn
better through an approach that deempha-
sizes letter–sound relations and instead
emphasizes either visually based retrieval or
reliance on context. These alternative meth-
ods work poorly, however (Lyon, 1995);
there is simply no substitute for being able
to sound out unfamiliar words. Indeed, what
seems to work best is to teach children with
dyslexia to use strategies that enhance their
phonological recoding (Lovett et al., 1994).
Effective strategies include drawing analo-
gies to known words with similar spellings;
generating alternative pronunciations of
vowels when the first attempt at sounding
out does not yield a plausible word; and,
with long words, “peeling off” prefixes and
suffixes and then trying to identify the rest
of the word. Using such strategies helps
children with dyslexia to improve their
reading-achievement scores (Lovett et al.,
1994).
BOX 8.3: individual differences
DYSLEXIA
Age
7–8 9–10 11–12 13–14
0
10
20
30
40
50
60
N
u
m
b
er
o
f
p
se
u
d
ow
or
d
s
id
en
ti
fi
ed
c
or
re
ct
ly
Children with reading disabilities
Typical children
this chart shows the number of pseudowords identi-
fied correctly by 7- to 14-year-olds with and without
reading disabilities. Note that 13- and 14-year-olds
with reading disabilities correctly identified no more
items than did typical 7- and 8-year-olds. the poor
phonological recoding skills of children with reading
disabilities lead them to have special difficulty with
pseudowords that, because they are totally unfa-
miliar, can be pronounced only by using phonological
recoding. (Data from Siegel, 1993)
dyslexia n inability to read and spell
well despite having normal intelligence

A C Q U I S I T I O n O f A C A D E m I C S K I L L S : R E A D I n G , W R I T I n G , A n D m A T h E m A T I C S n 327
Development of reading comprehension is also aided by acquisition of read-
ing strategies. For example, good readers proceed slowly when they need to master
written material in depth and speed up when they need only a rough sense of it
(Pressley & Hilden, 2006). Proficiency in making such adjustments develops sur-
prisingly late. Even when 10-year-olds are told that some material is crucial and
other material is not, they tend to read all the material at the same speed. In con-
trast, 14-year-olds skim the nonessential parts and spend more time on the impor-
tant ones (Kobasigawa, Ransom, & Holland, 1980).
Increasing metacognitive knowledge also contributes to improved reading com-
prehension. With age and experience, readers increasingly monitor their ongoing
understanding and reread passages they do not understand (Nicholson, 1999). Such
comprehension monitoring differentiates good readers from poor ones at all ages
from 1st grade through adulthood. Instructional approaches that focus on com-
prehension monitoring and other metacognitive skills, such as anticipating ques-
tions that a teacher might ask about the material, improve reading comprehension
(Palincsar & Magnusson, 2001; Rosenshine & Meister, 1994).
Another powerful influence on the development of reading comprehension is
increasing content knowledge. Relevant content knowledge frees cognitive re-
sources for focusing on what is new or complex in the text and allows readers to
draw reasonable inferences about information left unstated. Thus, when reading
the headline “Pirates Maul Giants,” readers knowledgeable about baseball realize
that the headline concerns a baseball game; it is unclear how readers who lack base-
ball knowledge would interpret such a headline.
The path to strong or weak reading comprehension begins even before children
start school. Hearing stories told or read by their parents helps preschoolers learn
how such stories tend to go, facilitating their understanding of new stories once
they read themselves. It also enhances their general level of language development
(Raikes et al., 2006; Whitehurst & Lonigan, 1998). The amount that parents read
to their children during the preschool years also partially accounts for the differ-
ences between the reading comprehension skills of children from middle- and
low-income families. For example, a study conducted in Israel showed that in an
affluent school district with high reading-achievement scores, 96% of parents of
preschoolers read to them daily. The same was true of only 15% of parents of pre-
schoolers in a poor district with low scores (Feitelson & Goldstein, 1986).
The straightforward implication of these findings is that if preschoolers from
poor families were read to daily, they too would become better readers. The evi-
dence is consistent with this inference. Encouraging low-income parents to also
actively engage their children in the reading process, such as by asking them to re-
late what is being read to their own experiences or to explain the characters’ goals
and motivations, helps even more (Zevenbergen & Whitehurst, 2003). Persuading
low- income parents to enroll in such programs and read to their children on a con-
tinuing basis is not easy, because of time demands and, in many cases, the pressures
of being a single parent (Whitehurst et al., 1999); but when parents do so, their
children’s reading comprehension benefits.
Once children enter school, the amount of material they read varies greatly and has
a large effect on their reading comprehension. For instance, U.S. 5th-graders whose
reading-achievement test scores are in the 90th percentile for their grade report
roughly 200 times as much discretionary reading as peers who score in the 10th per-
centile (Anderson, Wilson, & Fielding, 1988). High reading ability leads children to
read more; children who read more, in turn, show greater gains over time in reading
comprehension than do children of equal ability who read less (Guthrie et al., 1999).
comprehension monitoring n process
of keeping track of one’s understanding of
a verbal description or text

328 n chapter 8 InTELLIGEnCE AnD ACADEmIC AChIEVEmEnT
Individual Differences
Individual differences in reading ability tend to be stable over time. Children who
have relatively advanced reading skills when they enter kindergarten tend to be
better readers through elementary, middle, and high school (Duncan et al., 2007;
Harlaar, Dale, & Plomin, 2007). Studies of adoptive and nonadoptive siblings and
of monozygotic and dizygotic twins indicate that these continuities of individual
differences reflect both shared genes and shared environments (Petrill et al., 2007;
Wadsworth et al., 2006). As we have noted, genetic and environmental influences
are mutually reinforcing: parents who are good and frequent readers are likely to
provide both genes and environments that make it likely that their children will be
relatively good readers when they are young, which makes it more likely that the
children will seek out reading opportunities, which will further improve their read-
ing, and so on (Petrill et al., 2005).
Writing
Much less is known about the development of children’s writing than about the
development of their reading, but what is known shows interesting parallels be-
tween the two.
Prewriting Skills
The development of writing, like the development of reading, begins before chil-
dren receive formal schooling. Figure 8.11 displays writing efforts typical of a
3½-year-old. The marks are not conventional letters of the alphabet, but they look
vaguely like them and are arranged along a roughly horizon-
tal line. By age 4, children’s “writing” is sufficiently advanced
that adults have no trouble distinguishing it from the figures
4-year-olds produce when asked to draw a flower or a house
(Tolchnisky, 2003).
Preschoolers’ “writing” indicates that they expect mean-
ing to be reflected in print. They use more marks to repre-
sent words that signify many objects, such as “forest,” than
to represent words that signify a single object, such as “tree”
(Levin & Korat, 1993). Similarly, when asked to guess which of several words is the
name for a particular object, they generally choose longer words for larger objects
(Bialystok, 2000). Although written language does not work this way, the children’s
guess seems reasonable.
Generating Written Text
Learning to write, in the sense of writing an essay or story, is a good deal more
difficult than learning to read. This is not surprising, because writing requires
focusing simultaneously on numerous goals, both low level and high level. The
low-level goals include forming letters, spelling words, and using correct cap-
italization and punctuation. The high-level goals include making arguments
comprehensible without the intonations and gestures that help us communicate
when we speak, organizing individual points in a coherent framework, and pro-
viding the background information that readers need to understand the writing
(Berninger & Richards, 2002). The difficulties children have in meeting both
the low-level and high-level goals result in their often writing the type of flat
story illustrated in Figure 8.12.
FIGURE 8.11 a 3½-year-old’s effort
at writing the child’s symbols, although
unconventional, indicate an understanding
that words require separate symbols.

A C Q U I S I T I O n O f A C A D E m I C S K I L L S : R E A D I n G , W R I T I n G , A n D m A T h E m A T I C S n 329
As with development of reading comprehension, growth
of writing proficiency reflects improvements in basic pro-
cesses, strategies, metacognition, and content knowledge.
Automatizing low-level skills, such as spelling and punctua-
tion, aids writing not only because correct spelling and punc-
tuation make writing easier to understand but also because
automatizing the low-level skills frees cognitive resources for
pursuing the higher-level communicative goals of writing.
Consistent with this conclusion, children’s proficiency at low-
level skills such as spelling correlates positively with the qual-
ity of the children’s essays ( Juel, 1994).
Acquisition of strategies also contributes to improvements
in writing. One common strategy is to sequence high-level
goals in a standard organization, or script, a set of actions or
events that occurs repeatedly. Harriet Waters, a psychologist
whose proud mother saved all her daughter’s “class news” as-
signments from 2nd grade, was one child who employed such
an approach (Waters, 1980). As shown in Table 8.4, in each
class news essay, Waters first noted the date, then described
the weather, and then discussed events of the school day—a
strategy that greatly simplified her writing task. For older chil-
dren, formulating outlines serves a similar purpose of dividing
the task of writing into manageable parts: first figure out what
you want to say, then figure out the best order for making your
main points, then figure out how to make each point.
Metacognitive understanding plays several crucial roles in writing. Perhaps the
most basic type of metacognitive understanding is recognizing that readers may not
have the same knowledge as the writer and that one therefore should include all the
information that readers will need to allow them to grasp what is being said. Good
writers consistently exhibit such understanding by high school; poor writers often do
not (Berninger & Richards, 2002). A second crucial type of metacognitive knowl-
edge involves understanding the need to plan one’s writing rather than just jumping
in and starting to write. Good writers spend much more time than do poor writers
planning what they will say before they begin writing—making notes, constructing
FIGURE 8.12 a 4th-grader’s story
the intended title of this story was The
Kid Who Lost Things. See if you can figure
out the rest. (From Berninger & richards,
2002)
script n typical sequence of actions used
to organize and interpret repeated events,
such as eating at restaurants, going
to doctors’ appointments, and writing
reports
TABLE 8.4
Stories Written at Beginning, Middle, and end of Year for class News assignment
SEPTEMBER 24, 1956
Today is Monday, September, 24, 1956. It is a rainy day. We hope the sun will shine. We got new
spelling books. We had our pictures taken. We sang Happy Birthday to Barbara.
JANUARY 22, 1957
Today is Tuesday, January 22, 1957. It is a foggy day. We must be careful crossing the road. This
morning, we had music. We learned a new song. Linda is absent. We hope she comes back soon.
We had arithmetic. We made believe that we were buying candy. We had fun. We work in our
English books. We learned when to use is and are.
MAY 27, 1957
Today is Monday, May 27, 1957. It is a warm, cloudy day. We hope the sun comes out. This afternoon,
we had music. We enjoyed it. We went out to play. Carole is absent. We hope she comes back soon. We
had a spelling lesson, we learned about a dozen. Tomorrow we shall have show and tell. Some of us
have spelling sentences to do for homework. Danny brought in a cocoon. It will turn into a butterfly.
Source: H. S. Waters, 1980
E
LS
E
V
IE
R

330 n chapter 8 InTELLIGEnCE AnD ACADEmIC AChIEVEmEnT
outlines, and so on (Kellogg, 1994). Understanding the need for revision is a third
key type of metacognitive knowledge. Good writers spend more time revising their
already relatively good first drafts than poor writers spend revising their poorer ones
(Fitzgerald, 1992).
Fortunately, as with reading, instruction aimed at inculcating metacognitive
understanding can enhance writing skills (S. Graham & Harris, 1996). In particu-
lar, the writing of both typical and learning-disabled children improves when they
are taught to revise other children’s work and to ask themselves several basic ques-
tions: Who is the main character in this story? What does the main character do?
How do the other characters respond? How does the main character respond to the
other characters’ responses? What happens in the end? Asking children to reflect
on the relative quality of essays written by other children and on why some essays
are better than others also can improve writing (Braaksma et al., 2004).
Finally, as in reading, content knowledge plays a crucial role in writing. Children
generally write better when they are familiar with the topic than when they are not
(Bereiter & Scardamalia, 1982). Thus, the standard advice “Write what you know”
applies to children as well as to aspiring authors.
Mathematics
In Chapter 7, we examined infants’ early-developing nonverbal number sense
and the emergence of counting between ages 2 and 4 years. Here we examine the
development of arithmetic, which builds on both types of knowledge.
Arithmetic
People often think of arithmetic learning as a process of rote memorization, but
it actually is far more complex and interesting. How well children learn arithme-
tic depends on the strategies that they use, the precision of their representations
of numerical magnitudes, and their understanding of basic mathematical concepts
and principles.
Strategies From age 4 or 5 years, when most children begin to learn arithmetic,
they use a variety of problem-solving strategies. The most common initial strat-
egies are counting from 1 (e.g., solving 2 1 2 by putting up two fingers on each
FIGURE 8.13 Young children’s strategy choices in
(a) addition, (b) subtraction, and (c) multiplication as
illustrated previously with reading (Figure 8.10), a strong posi-
tive correlation exists between the difficulty of a problem,
as defined by the percentage of errors it elicits, and the fre-
quency of using an overt strategy, such as counting on one’s
fingers. thus, for problems that 4- and 5-year-olds found easy,
such as 2 1 2, they usually used retrieval. For problems they
found difficult, such as 4 1 3, they usually used overt strate-
gies, such as counting from 1. (Siegler, 1986)
100
90
80
70
60
50
40
30
20
10
0
Percent overt strategy use
P
er
ce
n
t
er
ro
rs
10 40 50 60 70 803020
1 + 1
1 + 2
1 + 4
4 + 4
4 + 5
3 + 5
4 + 3
3 + 4
5 + 4
2 + 4
2 + 5
4 + 2
3 + 2
3 + 3
1 + 3
2 + 2
2 + 1
2 + 3
5 + 1
5 + 2
5 + 3
1 + 5
3 + 1
4 + 1
Addition
r = .91
Addends ≤ 5
Sum ≤ 10
(a)

A C Q U I S I T I O n O f A C A D E m I C S K I L L S : R E A D I n G , W R I T I n G , A n D m A T h E m A T I C S n 331
hand and counting “1, 2, 3, 4”) and retrieval (recalling answers from
memory). At first, children can use these strategies only to answer
a few simple problems, such as 1 1 2 and 2 1 2, but they gradually
expand their use to a wider range of single-digit problems (Geary,
2006).
When children begin to do arithmetic on a daily basis, in kinder-
garten or first grade, they add several new strategies. One is count-
ing from the larger addend (e.g., solving 3 1 9 by counting, “9, 10, 11,
12”). Another fairly common strategy is decomposition, which involves
dividing a problem into two easier ones (e.g., solving 3 1 9 by think-
ing “3 1 10 5 13; 13 2 1 5 12”). Children continue to use the ear-
lier developing strategies as well; most 1st-graders use three or more
strategies to add single-digit numbers (Siegler, 1987).
Similarly varied strategy use is present on all four arithmetic oper-
ations. For example, to solve a multiplication problem such as 3 3 4,
children sometimes write three 4s and add them, sometimes make
three bundles of four hatch marks and count them, and sometimes
retrieve 12 from memory (Mabbott & Bisanz, 2003). Use of these
arithmetic strategies is surprisingly enduring: even college students
use strategies other than retrieval on 15% to 30% of single-digit
problems (LeFevre et al., 1996; Lemaire, 2010).
Just as children’s choices among word-identification strategies are highly adap-
tive, so are their choices among arithmetic strategies (Siegler, 1996). Even 4-year-
olds choose in sensible ways, usually solving easy problems such as 2 1 2 quickly
and accurately by using retrieval and usually solving harder problems such as 5 1
2 less quickly but still accurately by counting from 1 (Figure 8.13). As children
gain experience with the answers to single-digit arithmetic problems, their strat-
egy choices shift increasingly toward using retrieval of those answers. The learn-
ing process seems to be the same as with the corresponding shift toward visually
based retrieval in reading. The more often children generate the correct answer to
a problem, regardless of the strategy they use to generate it, the more often they
will be able to retrieve that answer, thereby avoiding the need to use slower count-
ing strategies.
Daddy, how many fingers do I hold up for five and a half?
Learning arithmetic is harder than it looks.
©
B
IL
K
E
A
n
E
,
In
C
.
/
K
In
G
f
E
AT
U
R
E
S
S
Y
n
D
IC
AT
E
90
80
70
60
50
40
30
20
10
0
Percent overt strategy use
P
er
ce
n
t
er
ro
rs
10 40 50 60 70 80 903020
r = .83
Multiplication
2 x 2
2 x 8
2 x 9
2 x 6
4 x 2 6 x 2
5 x 3
4 x 5, 5 x 58 x 2
8 x 5, 3 x 8, 5 x 4
7 x 2 3 x 6
7 x 9 8 x 9
8 x 7
9 x 7
6 x 7
7 x 7 7 x 8
8 x 6
7 x 6
4 x 9
6 x 9 6 x 6
7 x 4
7 x 5
5 x 8
9 x 5
6 x 5
9 x 3
8 x 3
8 x 4
5 x 7
3 x 7
7 x 3
4 x 7
8 x 8
4 x 8
9 x 6
9 x 4
9 x 9
9 x 8
6 x 85 x 9
4 x 6
5 x 6
3 x 9
6 x 4
3 x 3, 2 x 7
2 x 4
4 x 4
4 x 3 6 x 3
9 x 2
3 x 4
3 x 5
8 x 2
2 x 3
50
45
40
35
30
25
20
15
10
0
Percent overt strategy use
P
er
ce
n
t
er
ro
rs
10 40 50 60 70 803020
4 ñ 12 ñ 1
3 ñ 1
3 ñ 2
5 ñ 1
6 ñ 1
6 ñ 3
6 ñ 2
6 ñ 4
9 ñ 48 ñ 3
7 ñ 4
10 ñ 5
8 ñ 5
6 ñ 5
9 ñ 5
8 ñ 4
7 ñ 5
5 ñ 3
4 ñ 3
4 ñ 2
7 ñ 2 7 ñ 3
5 ñ 2
5 ñ 4
r = .83
Subtraction
(b) (c)

332 n chapter 8 InTELLIGEnCE AnD ACADEmIC AChIEVEmEnT
Understanding numerical magnitudes Numerical magnitude representations
are mental models of the way quantities are ordered along a less-to-more dimen-
sion. Regardless of whether “7” refers to a distance (7 inches), a weight (7 pounds), a
duration (7 hours), or a set size (7 people), the magnitude represented by “7” is larger
than that indicated by “6”—and smaller than that indicated by “8”—of the same unit.
The idea that symbolically expressed numbers represent magnitudes might seem
obvious, but accurately linking such numbers and the magnitudes they represent
actually constitutes a major challenge over a prolonged period of development. Here
are some examples: many preschoolers who can count flawlessly from 1 to 10 do
not know whether 4 or 8 indicates the greater number of
objects (Le Corre & Carey, 2007); many elementary school
children estimate the location of 150 as being near the mid-
point of a number line with 0 and 1000 at the two ends
(Siegler & Opfer, 2003); many adolescents and adults have
no idea whether 3/5 is larger or smaller than 5/11 (Meert,
Grégoire, & Noël, 2010). What is lacking in all these cases
is accurate representations of numerical magnitudes.
Understanding symbolic numerical magnitudes is
closely related to understanding arithmetic and indeed
to mathematics achievement in general. This relation is
evident in arithmetic errors, whose magnitudes usually
are close to the correct answer (8 3 7 5 54) rather than
far from it (8 3 7 5 24). Similarly, when asked whether
answers to arithmetic problems are correct, both children
and adults identify incorrect answers more quickly when the
magnitude of error is considerable (8 1 4 5 18) than when
it is small (8 1 4 5 14) (Ashcraft, 1982; Siegler, 1988).
The range of numbers whose magnitudes children rep-
resent reasonably precisely, as indicated by the accuracy of
their magnitude comparisons and number-line estimates,
changes greatly with age and experience (Figure 8.14).
Accuracy of magnitude representations of the numbers
1–10 increases greatly between ages 3 and 6 (Bertelletti
et al., 2010); that of numbers 1–100, between ages 6 and
8 (Geary et al., 2007); that of numbers 1–1000, between
ages 8 and 12 (Siegler & Opfer, 2003); and so on.
Children of any given age differ considerably in their
knowledge of numerical magnitudes. These differences are
related to the children’s overall mathematical knowledge.
During elementary school, children who more accurately
estimate whole-number magnitudes on number lines
have higher math achievement. During middle school,
0 20 100806040
M
ed
ia
n
E
st
im
at
e
Number Presented
100
80
60
40
20
0
(c) Second-Graders’ Median Estimates
0 20 100806040
M
ed
ia
n
E
st
im
at
e
Number Presented
100
80
60
40
20
0
(b) Kindergarteners’ Median Estimates
0 100
(a) A Number Line
FIGURE 8.14 the number-line task and typical developmental
changes on it (a) On each trial with a 0–100 number line, children
need to estimate a different number’s location on the line. (b) Kindergart-
ners’ median estimates for each number on the 0–100 number-line task
increased with the number being estimated, but in a way that involved
overestimates of relatively small numbers and underestimates of large
ones, as with a logarithmic function. (c) Second-graders’ median estimates
for each number on the same task increased linearly with the size of the
number being estimated, and were quite accurate. (Data from Siegler &
Booth, 2004)
numerical magnitude representa-
tions n mental models of the sizes of
numbers, ordered along a less-to-more
dimension
symbolic numerical magnitudes n
numbers expressed orally or in writing,
such as “7” or “seven”

A C Q U I S I T I O n O f A C A D E m I C S K I L L S : R E A D I n G , W R I T I n G , A n D m A T h E m A T I C S n 333
the same is true for children who accurately estimate
fraction magnitudes (Figure 8.15) (D. H. Bailey et al.,
2012; Jordan et al., 2013; Siegler & Pyke, 2013).
Part of the reason for this relation is that more accu-
rate magnitude representations help children learn arith-
metic. The more precisely a child understands numerical
magnitudes, as measured by his or her accuracy in esti-
mating the position of numbers on a number line, the
greater the child’s arithmetic proficiency ( J. L. Booth &
Siegler, 2006; 2008; Geary et al., 2007). Moreover, in-
struction that improves the accuracy of children’s sym-
bolic numerical magnitude representations also improves
their subsequent learning of arithmetic ( J. L. Booth &
Siegler, 2008; L. S. Fuchs et al., 2013; Siegler & Ramani,
2009). Accurate magnitude representations may enhance
arithmetic learning by suggesting plausible answers and
eliminating implausible ones from consideration.
conceptual understanding of arithmetic Under-
standing why some arithmetic procedures are appropriate and others inappropri-
ate poses a major challenge for many children, even those who have memorized the
correct procedure. Such conceptual understanding of arithmetic begins developing
during the preschool period; for example, many 4-year-olds understand the com-
mutative law of addition, the principle that adding a 1 b is the same as adding b 1
a (Canobi, Reeve, & Pattison, 2002). Not until years later, however, do they master
more advanced arithmetic concepts, such as mathematical equality—the idea that
the values on the two sides of the equal sign must balance. On almost all problems
in which young children encounter the equal sign, numbers appear only to the left
of it (e.g., 3 1 4 5 __ ; 3 1 4 1 5 5 __ ). For purposes of solving such problems,
children can interpret the equal sign merely as a signal to start adding.
Eventually, however, children encounter arithmetic problems with numbers on
both sides of the equal sign, such as 3 1 4 1 5 5 __ 1 5. As late as 4th grade, most
children in the United States answer such problems incorrectly (Goldin-Meadow,
Cook, & Mitchell, 2009). The most common incorrect approach is to add all the
numbers to the left of the equal sign, which in the above problem sum to 12, and to
assume that this sum is the answer to the problem. Such errors reflect not only a lack
of understanding that the equal sign means that the values on both sides of it must
be equivalent but also interference from the vast amount of practice children have
had solving typical addition problems, which have no number following the equal
sign (McNeil et al., 2011).
In many cases, children’s hand gestures reveal that they have somewhat better
understanding of mathematical equality than is revealed by their answers or explana-
tions. For example, on the problem 3 1 4 1 5 5 __ 1 5, children often answer “12”
and explain that they solved the problem by adding 3 1 4 1 5, but during their expla-
nation, they point to all four numbers rather than just to the three preceding the equal
sign. This pointing suggests an implicit recognition that the fourth number might be
important, even though they did not include it in their calculation (Goldin-Meadow
& Alibali, 2002). Children who initially show such gesture–speech mismatches, in
which their gesturing conveys more information than their verbal statements, learn
more from instruction on mathematical equality problems than do peers whose ges-
turing and speech before the instruction were consistent (that is, those who said “12”
and pointed only to the three numbers preceding the equal sign).
2200
2000
1800
1600
1400
1200
1000
0 10 6050403020
M
at
h
A
ch
ie
ve
m
en
t
Te
st
S
co
re
Percent Error of Estimates
R2 � 0.74
FIGURE 8.15 relation between 8th-
graders’ number-line estimation accu-
racy and their math achievement test
scores accuracy of number-line estimation
is closely related to overall mathematics
achievement. these data show the rela-
tion between middle school children’s math
achievement test scores and the accuracy
of their estimates of fraction magnitudes.
Similar relations have been found between
elementary school children’s math achieve-
ment test scores and their estimates of
whole-number magnitudes. the correla-
tion is negative, because estimates that are
less distant from numbers’ correct locations
indicate greater knowledge of the numerical
magnitudes. (Data from Siegler, thompson,
& Schneider, 2011)
mathematical equality n concept that
the values on each side of the equal sign
must be equivalent
gesture–speech mismatches n phe-
nomenon in which hand movements and
verbal statements convey different ideas

334 n chapter 8 InTELLIGEnCE AnD ACADEmIC AChIEVEmEnT
The gestures play a causal role in learning as well: children who are encouraged
to gesture appropriately while explaining answers to mathematical equality prob-
lems learn more than children encouraged not to gesture (Goldin-Meadow, Cook,
& Mitchell, 2009). The positive relation between gesture–speech mismatches and
subsequent learning has emerged on number conservation and physics problems
as well as on mathematical equality problems. These findings illustrate a common
conclusion: variability of thought and action (for example, generating diverging
gestures and speech or advancing multiple explanations of a phenomenon rather
than just one) often indicates heightened readiness to learn (Church, 1999; Siegler,
2006; Thelen & Smith, 2006).
Mathematics Anxiety
Many children experience mathematics anxiety, a negative emotional state that leads
to fear and avoidance of math (Ashcraft & Ridley, 2005). Such anxiety can be evi-
dent as early as 1st grade (Ramirez et al., 2012) and for many people presents a
lifelong problem. Mathematics evokes more anxiety than other school subjects,
probably because of the unambiguous right/wrong status of answers to many math-
ematics problems, the widespread belief that mathematics is closely linked to in-
telligence, and the frustrating periods with no apparent progress that mathematics
learning often entails.
Mathematics anxiety is considerably more prevalent in girls than in boys
(Devine et al., 2012). It is correlated with poor mathematics achievement, but
some people experience it despite having high mathematics achievement and
not suffering from high anxiety in general (Ashcraft & Krause, 2007; Maloney
& Beilock, 2012). The feelings of dread that math can inspire contribute to the
negative outcomes that are feared; a likely reason is that the anxiety reduces the
working memory resources needed to solve mathematics problems (Beilock &
DeCaro, 2007). Consistent with this interpretation, when presented with math-
ematics tasks, people with math anxiety show both unusually great activity on
the right side of the amygdala, a part of the brain involved in processing nega-
tive emotions, and depressed activity in brain areas crucial to working memory
(C. B. Young, Wu, & Menon, 2012).
How do some children become anxious about math? The mechanisms are not
well understood, but one contributor appears to be the views of adults who are
important in the children’s lives. Parents and teachers who are themselves anxious
about mathematics tend to convey their beliefs and feelings to their children. The
problem seems to be especially great for girls whose parents and teachers are pes-
simistic about girls’ mathematical abilities (Beilock et al., 2010; Meece, Wigfield,
& Eccles, 1990).
The negative impact of anxiety on mathematics learning has prompted efforts
to find ways of reducing it. One promising intervention is surprisingly simple: have
students write a brief description of their emotions just before taking a test. Such
expressive writing reduces anxiety and boosts performance in a variety of areas in
which negative emotions interfere with learning and performance, including math-
ematics (Ramirez & Beilock, 2011). Putting the negative thoughts on paper might
help students think about the situation more objectively and thus allow them to
concentrate on the math problems.
Even among children with mathematics anxiety, most learn the basics reasonably
well. However, as noted in Box 8.4, the learning process goes seriously awry with
certain children who suffer from the general difficulty in thinking about numbers
that is known as mathematics disability.

A C Q U I S I T I O n O f A C A D E m I C S K I L L S : R E A D I n G , W R I T I n G , A n D m A T h E m A T I C S n 335
review:
Learning to read begins in preschool, when many children come to recognize the letters of the
alphabet and gain phonemic awareness. Early in elementary school, children learn to identify
words through two main processes—phonological recoding and visually based retrieval—and
they choose adaptively between these strategies. Reading comprehension improves through
automatization of word identification, development of strategies, and acquisition of meta-
cognition and content knowledge. How much parents read to their children and, later, how
much the children themselves read also influence reading development.
Learning to write well is difficult. It requires focusing simultaneously on low-level goals
(proper spelling, punctuation, and capitalization) and high-level goals (making arguments
clear and persuasive). Many Western children enter school knowing that writing proceeds in
a horizontal sequence from left to right, that the text on one line continues on the next, and
that words are separated by small spaces. Improvements in writing with age and experience
reflect automatization of low-level goals, new organizational strategies, growing metacognitive
understanding of what readers need to be told, and increasing content knowledge.
Mathematical development follows a similar general pattern. Most children enter school
with some useful knowledge, such as knowing how to count from 1 to solve addition problems.
Once in school, children learn a wide range of strategies for solving arithmetic and other math-
ematical problems, and they generally choose among these strategies in sensible ways. They
BOX 8.4: applications
MATHEMATICS DISABILITIES
Between 5% and 8% of children perform
so poorly in math that they are classified
as having a mathematics disability (Shalev,
2007). These children have IQ scores in
the normal range (85 or higher) but per-
form extremely poorly in mathematics. In
the first few grades, they tend to be slow to
learn to count, to learn the relative magni-
tudes of numbers, and to accurately solve
single-digit arithmetic problems (Geary
et al., 2008; Jordan, 2007). Their per-
formance improves with experience, but
even in later grades and adulthood, most
continue to be slow at single-digit arith-
metic and to have difficulty with the many
mathematical skills that build on it, such
as multidigit arithmetic, fractions, and
algebra (Geary et al., 2012; Hecht & Vagi,
2010).
Although people often think of mathe-
matics as a type of knowledge necessary for
school but not afterward, the experience of
adults with mathematics disabilities illus-
trates the lifelong debilitating effects of this
problem:
I worked for Nabisco. As a mixer, you
had to know the correct scale and
formulas. I kept messing up. I lost
my job.
(Curry, Schmitt, & Waldron,
1996, p. 63)
Dairy Queen wouldn’t hire me be-
cause I couldn’t make change in my
head.
(Curry, Schmitt, & Waldron,
1996, p. 63)
For as long as I can remember, num-
bers have not been my friend.
(Blackburn, cited in
M. McCloskey, 2007, p. 415)
Several specific problems contribute to
mathematics disabilities (Geary et al., 2012).
In severe cases, damage to one or more brain
areas that are central to numerical process-
ing, such as the intraparietal sulcus, is often
the cause (Butterworth, 2010; T. J. Simon &
Rivera, 2007). In less severe cases, minimal
exposure to numbers prior to beginning school
often contributes. Children who start school
lacking knowledge of the key mathemati-
cal concepts and skills that their peers pos-
sess tend to lag far behind throughout school
(Duncan et al., 2007). Other variables that
are associated with, and might cause, math-
ematics disabilities are poor working mem-
ory for numbers, poor executive functioning,
slow processing of numerical information, and
mathematics anxiety (C. Blair & Razza, 2007;
Lyons & Beilock, 2012; Mazzocco & Kover,
2007; Raghubar, Barnes, & Hecht, 2010).
A variety of programs have been designed
to improve the mathematics knowledge of
children with mathematics disabilities. One
particularly successful program (L. S. Fuchs
et al., 2013) emphasized learning of frac-
tion magnitudes through instruction in mag-
nitude comparison (e.g., “Which is larger: ½
or 1⁄5?”) and number-line estimation (e.g.,
“Where would 1⁄5 go on this number line?”).
The instruction, which was implemented
with 9- and 10-year-olds, not only improved
the children’s learning of these capabilities
but also improved their learning of fraction
arithmetic, relative to that of children who re-
ceived a greater amount of fraction arithmetic
instruction in the classroom but less instruc-
tion in understanding fraction magnitudes.
Such findings indicate that effective instruc-
tion can reduce the problems associated with
mathematics disabilities.

336 n chapter 8 InTELLIGEnCE AnD ACADEmIC AChIEVEmEnT
also learn about an increasing range of numerical magnitudes, which improves their arithmetic
learning. Understanding underlying concepts and principles also is an essential part of learn-
ing mathematics. On the other hand, mathematics anxiety can interfere with performance and
learning, because the heightened emotions reduce working-memory resources.
chapter summary:
n Alfred Binet and his colleague Théophile Simon developed the
first widely used intelligence test. Its purpose was to identify
children who were unlikely to benefit from standard instruc-
tion in the classroom. Modern intelligence tests are descen-
dants of the Binet-Simon test.
n One of Binet’s key insights was that intelligence includes
diverse high-level capabilities that need to be assessed in order
to measure intelligence accurately.
What Is Intelligence?
n Intelligence can be viewed as a single trait, such as g; as a few
separate abilities, such as Thurstone’s primary mental abilities;
or as a very large number of specific processes, such as those
described in information-processing analyses.
n Intelligence is often measured through use of IQ tests, such as
the Stanford-Binet and the WISC. These tests examine gen-
eral information, vocabulary, arithmetic, language compre-
hension, spatial reasoning, and a variety of other intellectual
abilities.
Measuring Intelligence
n A person’s overall score on an intelligence test, the IQ score,
is a measure of general intelligence. It reflects the individual’s
intellectual ability relative to age peers.
n Most children’s IQ scores are quite stable over periods of years,
though scores do vary somewhat over time.
IQ Scores as Predictors of Important Outcomes
n IQ scores correlate positively with long-term educational and
occupational success.
n Other factors, such as social understanding, creativity, and
motivation also influence success in life.
Genes, Environment, and the Development
of Intelligence
n Development of intelligence is influenced by the child’s own
qualities, by the immediate environment, and by the broader
societal context.
n Genetic inheritance is one important influence on IQ score.
This influence tends to increase with age, in part due to some
genes not expressing themselves until late childhood or adoles-
cence, and in part due to genes influencing children’s choices
of environments.
n A child’s family environment, as measured by the HOME,
is related to the child’s IQ score. The relation reflects within-
family influences, such as parents’ intellectual and emotional
support for the particular child, as well as between-family influ-
ences, such as differences in parental wealth and education.
n Schooling positively influences IQ score and school
achievement.
n Broader societal factors, such as poverty and discrimination
against racial and ethnic minorities, also influence children’s
IQ scores.
n To alleviate the harmful effects of poverty, the United States has
undertaken both small-scale preschool intervention programs
and the much larger Project Head Start. Both have initial posi-
tive effects on intelligence and school achievement, though the
effects fade over time. On the other hand, the programs have
enduring positive effects on the likelihood of not being held
back in a grade and the likelihood of completing high school.
n Intensive intervention programs, such as the Carolina Abece-
darian Project, that begin in the child’s first year and provide
optimal child-care circumstances and structured academic cur-
ricula have produced increases in intelligence that continue
into adolescence and adulthood.
Alternative Perspectives on Intelligence
n Novel approaches to intelligence, such as Gardner’s mul-
tiple intelligences theory and Sternberg’s theory of successful
intelligence, attempt to broaden traditional conceptions of
intelligence.
Acquisition of Academic Skills: Reading, Writing,
and Mathematics
n Many children learn letter names and gain phonemic aware-
ness before they start school. Both skills correlate with later
reading achievement, and phonemic awareness also is causally
related to it.
n Word identification is achieved by two main strategies: phono-
logical recoding and visually based retrieval.

C h A P T E R S U m m A R Y n 337
chapter summary:
n Reading comprehension benefits from automatization of word
identification, because it frees cognitive resources for under-
standing the text. Use of strategies, metacognitive understanding,
and content knowledge also influence reading comprehension,
as does the amount that parents read to their children and the
amount that children themselves read.
n Although many children begin to write during the preschool
period, writing well remains difficult for many years. Much
of the difficulty comes from the fact that writing well requires
children to attend simultaneously to low-level processes, such
as punctuation and spelling, and to high-level processes, such
as anticipating what readers will and will not know.
n As with reading, automatization of basic processes, use of
strategies, metacognitive understanding, and content knowl-
edge influence development of writing.
n Most children use several strategies to learn arithmetic,
such as adding by counting from 1, counting from the larger
addend, and retrieving answers from memory. Children typi-
cally choose in adaptive ways, using more time-consuming
and effortful strategies only on the more difficult prob-
lems where such approaches are needed to generate correct
answers.
n Precise representations of numerical magnitudes are crucial for
learning arithmetic and other mathematical skills.
n As children encounter more advanced math, conceptual under-
standing becomes increasingly important. Understanding
mathematical equality, for example, is essential for grasping
advanced arithmetic and algebra problems.
Critical Thinking Questions
1. Intelligence can be viewed as a single ability, several abilities,
or many processes. List the characteristics that you think are
the most important components of intelligence and explain
their relevance.
2. Individual differences in intelligence are more stable than
individual differences in other areas of psychological func-
tioning such as emotional regulation or aggression. Why do
you think this is so?
3. Among children from middle- and upper-income families,
genetics are more influential than the shared environment
on individual differences in intelligence, but among children
from low-income families, the opposite is the case. Why do
you think that is?
4. Participation in Head Start does not lead to higher IQ or
achievement test scores by the end of high school, but it
does lead to lower rates of dropping out or being placed
in special-education classes. Why do you think this is the
case?
5. Explain Chall’s (1979) statement: “In the primary grades,
children learn to read; in the higher grades, they read to
learn.”
6. The development of reading, writing, and mathematics
shows a number of similarities. What are these similarities,
and why do you think development occurs in similar ways in
the three areas?
Key Terms
Carolina Abecedarian Project, p. 318
comprehension monitoring, p. 327
crystallized intelligence, p. 300
dyslexia, p. 326
fluid intelligence, p. 299
Flynn effect, p. 313
g (general intelligence), p. 299
gesture–speech mismatches, p. 333
IQ (intelligence quotient), p. 304
mathematical equality, p. 333
mental model, p. 325
multiple intelligences theory, p. 320
normal distribution, p. 304
numerical magnitude representations, p. 332
phonemic awareness, p. 322
phonological recoding skills, p. 322
primary mental abilities, p. 300
script, p. 329
self-discipline, p. 307
standard deviation (SD), p. 304
strategy–choice process, p. 324
symbolic numerical magnitudes, p. 332
theory of successful intelligence, p. 321
three-stratum theory of intelligence, p. 300
visually based retrieval, p. 324
Wechsler Intelligence Scale for Children
(WISC), p. 302

338
D O R OT H E A S H A R P, Building a Sandcastle
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chapter 9:
Theories of Social
Development
n Psychoanalytic Theories
View of Children’s Nature
Central Developmental Issues
Freud’s Theory of Psychosexual Development
Erikson’s Theory of Psychosocial Development
Current Perspectives
Review
n Learning Theories
View of Children’s Nature
Central Developmental Issues
Watson’s Behaviorism
Skinner’s Operant Conditioning
Social Learning Theory
Box 9.1: A Closer Look Bandura and Bobo
Current Perspectives
Review
n Theories of Social Cognition
View of Children’s Nature
Central Developmental Issues
Selman’s Stage Theory of Role Taking
Dodge’s Information-Processing Theory of Social
Problem Solving
Dweck’s Theory of Self-Attributions and
Achievement Motivation
Current Perspectives
Review
n Ecological Theories of Development
View of Children’s Nature
Central Developmental Issues
Ethological and Evolutionary Theories
The Bioecological Model
Box 9.2: Individual Differences Attention-Deficit
Hyperactivity Disorder
Box 9.3: Applications Preventing Child Abuse
Current Perspectives
Review
n Chapter Summary

340
I
magine yourself interacting face-to-face with an infant. What would it be like?
You naturally smile and speak in an affectionate tone of voice, and the infant
probably smiles and makes happy sounds back at you. If for some reason you
speak in a loud, harsh voice, the baby becomes quiet and wary. If you look off
to the left, the infant follows your gaze, as though assuming there is something
interesting to see in that direction. Of course, the baby does not just respond to
what you do; the baby also engages in independent behaviors, examining vari-
ous objects or events in the room or maybe fussing for no obvious reason. Your
interaction with the baby evokes emotions in you—joy, affection, frustration,
and so on. Over time, through repeated interactions, you and the infant learn
about each other and smile and vocalize more readily to each other than to
someone else.
Now, imagine that you are asked to interact with Kismet, the robot pictured
below, just as you would with a human infant. Although the request might seem
strange, Kismet’s facelike features make you willing to give it a try. So you smile
and speak in an affectionate tone—“Hi, Kismet, how are you?” Kismet smiles back
at you and gurgles happily. You speak harshly, “Kismet, stop that right now.” The
robot looks surprised—even a bit frightened—and makes a whimpering sound.
You find yourself spontaneously attempting to console Kismet: “I’m sorry; I didn’t
mean it.” After just a few moments, you have lost your feeling of self-consciousness
and find the interaction with your new metallic friend remarkably natural. You may
even start to feel fond of Kismet.
Kismet exists, and the robot’s behavior is pretty much as we have just de-
scribed it. One of the world’s first “social robots,” Kismet was designed by a team
of scientists headed by Cynthia Breazeal. Their primary goal was to develop
robots that, instead of being programmed to behave in specific ways, are pro-
grammed to learn from their social interactions with humans, just as infants do.
Accordingly, they designed Kismet as a sociable, “cute” infantlike robot that could
elicit the attention of, and “nurturing” from, humans. Kismet’s behavior is readily
Themes
n Nature and Nurture
n The Active Child
n Continuity/Discontinuity
n Mechanisms of Change
n The Sociocultural Context
n Individual Differences
n Research and Children’s
Welfare
Like that between a mother and her infant, a
face-to-face interaction between Kismet and
its designer involves talking, cooing back
and forth, and responding to each other’s
facial expressions. PE
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P S Y C H O A N A L Y T I C T H E O R I E S n 341
interpretable in human terms, and the robot even seems to have internal mental
and emotional states and a personality. Kismet learns from its interactions with
people—from the instructions it receives from them and from their reactions to
its behavior. Through these interactions with others, Kismet figures out how to
interpret facial expressions, how to communicate, what behaviors are acceptable
and unacceptable, and so on. Thus, Kismet develops over time as a function of the
interaction between the “innate” structure built into it and its subsequent socially
mediated experience. Just like a baby!
The challenge for Kismet’s designers was in many ways like the task of de-
velopmental scientists who attempt to account for how children’s development is
shaped through their interactions with other people. Any successful account of
social development must include the many ways we influence one another, starting
with the simple fact that no human infant can survive without intensive, long-term
care by other people. We learn how to behave on the basis of how others respond
to our behavior; we learn how to interpret ourselves according to how others treat
us; and we interpret other people by analogy to ourselves—all in the context of
social interaction and human society. Over the past few years, Kismet’s designers,
as well other pioneers in the field, have made important strides in their efforts to
allow their increasingly more sophisticated robot infants to develop and learn from
others. Indeed, some researchers predict that within a few years, they will have
developed cyberbabies that can acquire the cognitive and social abilities of a typical
3-year-old human child.
In this chapter, we review some of the most important and influential general
theories of social development, theories that attempt to account for how children’s
development is affected by the people and social institutions around them. In our
survey of cognitive theories in Chapter 4, we discussed some of the reasons why
theories are important (pages 130–131); those reasons apply equally well to theo-
ries of social development.
Theories of social development attempt to account for many important aspects
of development, including emotion, personality, attachment, self, peer relationships,
morality, and gender. In this chapter, we will describe four types of theories that
address these topics, reflecting, in turn, the psychoanalytic, learning, social cogni-
tive, and ecological perspectives. We will discuss the basic tenets of each theory and
examine some of the relevant evidence.
Every one of our seven themes appears in this chapter, with three of them being
particularly prominent. The theme that pervades this chapter most extensively
is individual differences, as we examine how the social world differentially affects
children’s development. The theme of nature and nurture helps us to distinguish
between the theories, because they vary in the degree to which they emphasize bio-
logical and environmental factors. The active child theme is also a major focus: some
of the theories emphasize children’s active participation in, and effect on, their own
socialization, whereas others view children’s development as shaped primarily by
external forces.
Psychoanalytic Theories
No psychological theory has had a greater impact on Western culture and on think-
ing about personality and social development than the psychoanalytic theory of
Sigmund Freud (1856–1939). A successor to Freud’s theory, the life-span develop-
mental theory of Erik Erikson (1902–1994), has also been quite influential.

342 n chapter 9 THEORIES Of SOCIAL DEvELOPMENT
View of Children’s Nature
In both Freud’s and Erikson’s theories, development is largely driven by biologi-
cal maturation. For Freud, behavior is motivated by the need to satisfy basic drives.
These drives, and the motives that arise from them, are mostly unconscious, and
individuals often have only the dimmest understanding of why they do what they
do. In Erikson’s theory, development is driven by a series of developmental cri-
ses related to age and biological maturation. To achieve healthy development, the
individual must successfully resolve these crises.
Central Developmental Issues
Three of our seven themes—continuity/discontinuity, individual differences, and
nature and nurture—play prominent roles in psychoanalytic theory. Like Piaget’s
theory of cognitive development that you encountered in Chapter 4, the devel-
opmental accounts of Freud and Erikson are stage theories. However, within the
framework of discontinuous development, psychoanalytic theories stress the con-
tinuity of individual differences, emphasizing that children’s early experiences have
a major impact on their subsequent development. The interaction of nature and
nurture arises in terms of Freud and Erikson’s emphasis on the biological under-
pinnings of developmental stages and how they interact with the child’s experience.
Freud’s Theory of Psychosexual Development
Freud began his career as a neurologist and soon became interested in the origins
and treatment of mental illness. He was particularly intrigued by the fact that some-
times his patients’ symptoms—such as loss of feeling in a hand or blindness—had
no apparent physical cause. After listening to his patients talk about their problems,
he came to the conclusion that these unexplained symptoms could be attributed
to completely unconscious but powerful feelings of guilt, anxiety, or fear—such as
the fear of touching or seeing something forbidden. Freud’s interest in psychologi-
cal development grew as he became increasingly convinced that the majority of his
patients’ emotional problems originated in their early childhood relationships, par-
ticularly those with their parents. Freud made fundamental, lasting contributions
to developmental psychology, although, as we will discuss later, they had to do with
certain broad psychological concepts, not with the specifics of his theory.
In our discussion of Freud’s theoretical views, we will focus primarily on their
developmental aspects, especially the broad themes that remain influential today.
Basic Features of Freud’s Theory
Freud’s theory of development is referred to as a theory of psychosexual develop-
ment because he thought that even very young children have a sexual nature that
motivates their behavior and influences their relationships with other people. He
proposed that children pass through a series of universal developmental stages.
According to Freud, in each successive stage, psychic energy—the biologically
based, instinctual drives that fuel behavior, thoughts, and feelings—becomes
focused in different erogenous zones, that is, areas of the body that are erotically
sensitive (e.g., the mouth, the anus, and the genitals). Freud believed that in each
stage, children encounter conflicts related to a particular erogenous zone, and he
maintained that their success or failure in resolving these conflicts affects their
development throughout life.
Sigmund Freud, the father of psychoanal-
ysis, has had a lasting influence on develop-
mental psychology through his emphasis on
the lifelong impact of early relationships.
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psychic energy n Freud’s term for the
collection of biologically based instinc-
tual drives that he believed fuel behavior,
thoughts, and feelings
erogenous zones n in Freud’s theory,
areas of the body that become eroti-
cally sensitive in successive stages of
development

P S Y C H O A N A L Y T I C T H E O R I E S n 343
The Developmental Process
In Freud’s view, development starts with a helpless infant beset by instinctual
drives, foremost among them hunger, which creates tension. The young infant
has no knowledge of how to reduce it, so the distress associated with hunger is
expressed through crying, prompting the mother to breast-feed the baby. (In
Freud’s day, virtually all babies were breast-fed.) The resulting satisfaction of the
infant’s hunger, as well as the experience of nursing, is a source of intense pleasure
for the infant.
The instinctual drives with which the infant is born constitute the id—the ear-
liest and most primitive of three personality structures posited by Freud. The id,
which is totally unconscious, is the source of psychic energy. It is the “dark, inac-
cessible part of our personality . . . a cauldron full of seething excitations” in need of
satisfaction (Freud, 1933/1964). The id is ruled by the pleasure principle—the goal
of achieving maximal gratification maximally quickly. Whether the gratification
involves eating, drinking, eliminating, or physical comfort, the id wants it now. The
id remains the source of psychic energy throughout life, with its operation most
apparent in selfish or impulsive behavior in which immediate gratification is sought
with little regard for consequences.
During the first year of life, the infant is in Freud’s first stage of psychosexual
development, the oral stage, so called because the primary source of gratification
and pleasure is oral activity, such as sucking and eating. “If the infant could express
itself, it would undoubtedly acknowledge that the act of sucking at its mother’s
breast is far and away the most important thing in life” (Freud, 1920/1965). The
pleasure associated with breast-feeding is so intense that other oral activities—
sucking on a thumb or pacifier, for instance—also provide pleasure.
For Freud, the baby’s feelings for his or her mother are “unique, without paral-
lel,” and through them the mother is “established unalterably for a whole lifetime
as the first and strongest love-object and as the prototype for all later love-relations”
(1940/1964).
The infant’s mother is also a source of security. However, this security does not
come without costs. As always with Freud, there is a dark side: infants “pay for this
security by a fear of loss of love” (Freud, 1940/1964). For Freud, common fearful
reactions to being alone or in the dark are based on “missing someone who is loved
and longed for” (1926/1959).
Later in the first year, the second personality structure, the ego, begins to emerge.
It arises out of the need to resolve conflicts between the id’s unbridled demands for
immediate gratification and the restraints imposed by the external world. Whereas
“the id stands for the untamed passions,” the ego “stands for reason and good sense”
(1933/1964). The ego operates under the reality principle, trying to find ways to
satisfy the id that accord with the demands of the real world. Over time, as it con-
tinually seeks resolution between the demands of the id and those of the real world,
the ego begins to develop into the individual’s sense of self. Nevertheless, the ego is
never fully in control:
The ego’s relation to the id might be compared with that of a rider to his horse. The
horse supplies the locomotive energy, while the rider has the privilege of deciding
on the goal and of guiding the powerful animal’s movement. But only too often . . .
the rider [is] obliged to guide the horse along the path by which it itself wants to go.
(Freud, 1933/1964, p. 77)
During the infant’s second year, maturation facilitates the development of
control over some bodily processes, including urination and defecation. At this
id n in psychoanalytic theory, the earliest
and most primitive personality structure.
It is unconscious and operates with the
goal of seeking pleasure.
oral stage n the first stage in Freud’s
theory, occurring in the first year, in
which the primary source of satisfaction
and pleasure is oral activity
ego n in psychoanalytic theory, the
second personality structure to develop.
It is the rational, logical, problem-solving
component of personality.

344 n chapter 9 THEORIES Of SOCIAL DEvELOPMENT
point, the infant enters Freud’s second stage, the anal stage, which lasts until
roughly age 3. In this stage, the child’s erotic interests focus on the pleasur-
able relief of tension derived from defecation. Conflict ensues when, for the first
time, the parents begin to make specific demands on the infant, most notably
their insistence on toilet training. In the years to come, parents and others will
increase their demands on the child to control his or her impulses and to delay
gratification.
Freud’s third stage of development, the phallic stage, spans the ages of 3 to 6. In
this stage, the focus of sexual pleasure again migrates, as children become interested
in their own genitalia and curious about those of parents and playmates. Both boys
and girls derive pleasure from masturbation, an activity that the parents of Freud’s
time and place often punished severely.
Freud believed that during the phallic stage, children identify with their same-
sex parent, giving rise to gender differences in attitudes and behavior. This identi-
fication begins with children’s discovery of the vital difference between having and
lacking a penis. At this time, a boy takes a strong interest in his penis, “so easily
excitable and changeable, and so rich in sensations” (Freud, 1923/1960, p. 246).
Freud supposed that girls notice and resent the fact that they do not have one,
experiencing what he called penis envy.
Freud also believed that young children experience intense sexual desires dur-
ing the phallic stage, and he proposed that their efforts to cope with them leads
to the emergence of the third personality structure, the
superego. The superego is essentially what we think of as
conscience. It enables a child to control his or her own
behavior on the basis of beliefs about right and wrong. The
superego is based on the child’s internalization, or adop-
tion, of the parents’ rules and standards for acceptable and
unacceptable behavior. The superego guides the child to
avoid actions that would result in guilt, which the child
experiences when violating these internalized rules and
standards.
For boys, the path to superego development is through
the resolution of the Oedipus complex, a psychosexual
conflict in which a boy experiences a form of sexual desire
for his mother and wants an exclusive relationship with
her. Although this idea may seem outlandish, many family
stories are consistent with it. For example, when one of our
sons was a 5-year-old, he told his mother that he wanted
to marry her someday. She said that she was sorry, but she
was already married to Daddy, so he would have to marry
someone else. The boy replied, “I have a good idea. I’ll put Daddy in a big box
and mail him away somewhere. Then we can get married!”
In Freud’s account of the Oedipal conflict, the son’s desire for his mother and
his hostility toward his father are highly threatening. In response, the boy’s ego
protects him through repression, banishing his dangerous feelings to the uncon-
scious, the mental storehouse where anxiety-producing thoughts and impulses are
held hidden from conscious awareness. A consequence of this widespread repres-
sion, according to Freud, is infantile amnesia—the lack of memories from our first
few years that we all suffer. In addition, the boy increases his identification with
his father: through striving to be like him, the boy internalizes his father’s values,
through identifying with his father, this
young boy should, according to Freud’s
theory, develop a strong superego.
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anal stage n the second stage in Freud’s
theory, lasting roughly from 1 to 3 years
of age, in which the primary source of
pleasure comes from defecation
phallic stage n the third stage in
Freud’s theory, lasting from age 3 to age
6, in which sexual pleasure is focused on
the genitalia
superego n in psychoanalytic theory, the
third personality structure, consisting of
internalized moral standards
internalization n the process of
adopting as one’s own the attributes,
beliefs, and standards of another person
Oedipus complex n Freud’s term for
the conflict experienced by boys in the
phallic period because of their sexual
desire for their mother and their fear of
retaliation by their father. (The complex
is named for the king in Greek mythology
who unknowingly murdered his father and
married his mother.)

P S Y C H O A N A L Y T I C T H E O R I E S n 345
beliefs, and attitudes, leading to the development of a strong conscience. Freud
thought that girls experience a similar but less intense conflict—the Electra com-
plex, involving erotic feelings toward the father—which results in their developing
a weaker conscience than boys do.
The fourth developmental stage, the latency period, lasts from about age 6
to age 12. It is, as its name implies, a time of relative calm. Sexual desires are
safely hidden away in the unconscious, and psychic energy gets channeled into
constructive, socially acceptable activities, including both intellectual and social
pursuits.
The fifth and final stage, the genital stage, begins with the advent of sexual
maturation. The sexual energy that had been kept in check for several years reas-
serts itself with full force, although it is now, for the majority of individuals, di-
rected toward other-sex peers. Ideally, the individual has developed a strong ego
that facilitates coping with reality and a superego that is neither too weak nor too
strong.
Freud thought that healthy development culminates in the ability to invest
oneself in, and derive pleasure from, both love and work. This outcome can be
compromised in many ways, however. If fundamental needs are not met dur-
ing any of the stages of psychosexual development, children may become fixated
on those needs, continually attempting to satisfy them and to resolve associ-
ated conflicts. In Freud’s view, these unsatisfied needs, and the person’s ongoing
attempts to fulfill them, are unconscious and are expressed in indirect or symbolic
ways. For example, if an infant’s needs for oral gratification are not adequately
satisfied during the oral stage, later in life the individual may repeatedly engage
in substitute oral activities, such as excessive eating, nail-biting, smoking, and so
on. Similarly, if toddlers are subjected to very harsh toilet training during the anal
stage, they may remain preoccupied with issues related to cleanliness, becoming
compulsively tidy and psychologically rigid or extremely sloppy and lax. Thus, in
Freud’s view, the nature of the child’s passage through the stages of psychosexual
development shapes the individual’s personality for life. (With regard to oral and
anal fixations, it is interesting that Freud smoked 20 cigars a day for more than 50
years—in fact, he found it impossible to work without them—and over the same
period followed the same ritualized schedule nearly every day.)
Erikson’s Theory of Psychosocial Development
Of the many followers of Freud, none has had greater influence in developmental
psychology than Erikson. Erikson accepted the basic elements of Freud’s theory
but incorporated social factors into it, including cultural influences and con-
temporary issues, such as juvenile delinquency, changing sexual roles, and the
generation gap. Consequently, his theory is regarded as a theory of psychosocial
development.
The Developmental Process
Erikson proposed eight age-related stages of development that span infancy to old
age. Each of Erikson’s stages is characterized by a specific crisis, or set of develop-
mental issues, that the individual must resolve. If the dominant issue of a given
stage is not successfully resolved before the onset of the next stage, the person
will continue to struggle with it. In the following summary of Erikson’s stages, we
erik erikson, who was born in Germany, took
a long time to settle into a career. Instead
of attending college, he wandered around
europe pursuing his interest in art for sev-
eral years. eventually, he was hired as an
art instructor in a school run by anna Freud,
Sigmund Freud’s daughter, and became an
analyst. he moved to the United States in
the early 1930s, when fascism was on the
rise in Germany.
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Electra complex n Freud’s term for the
conflict experienced by girls in the phallic
stage when they develop unacceptable
romantic feelings for their father and see
their mother as a rival. (The complex is
named after a figure in Greek mythology
who arranged for the murder of her
mother.)
latency period n the fourth stage in
Freud’s theory, lasting from age 6 to age
12, in which sexual energy gets chan-
neled into socially acceptable activities
genital stage n the fifth and final stage
in Freud’s theory, beginning in adoles-
cence, in which sexual maturation is
complete and sexual intercourse becomes
a major goal

346 n chapter 9 THEORIES Of SOCIAL DEvELOPMENT
discuss only the first five stages, which focus on development in infancy, childhood,
and adolescence.
1. Basic Trust Versus Mistrust (the first year). In Erikson’s first stage (which cor-
responds to Freud’s oral stage), the crucial issue for the infant is developing
a sense of trust—“an essential trustfulness of others as well as a fundamental
sense of one’s own trustworthiness” (Erikson, 1969, p. 96). If the mother is
warm, consistent, and reliable in her caregiving, the infant learns that she
can be trusted. More generally, the baby comes to feel good and reassured by
being close to other people. If the ability to trust others when it is appropriate
to do so does not develop, the person will have difficulty forming intimate
relationships later in life.
2. Autonomy Versus Shame and Doubt (ages 1 to 3½). The challenge for the child
between ages 1 year and 3½ years (Freud’s anal stage) is to achieve a strong
sense of autonomy while adjusting to increasing social demands. Going well
beyond Freud’s focus on toilet training, Erikson pointed out that during this
period, the dramatic increases that occur in every realm of children’s real-
world competence—including motor skills, cognitive abilities, and
language—foster children’s desires to make choices and decisions for them-
selves. Infants’ newfound ability to explore the environment on their own (as
we discussed in Chapter 5) changes the family dynamics, initiating a long-
running battle of wills in which parents try to restrict the child’s freedom and
teach the child which behaviors are acceptable and unacceptable. If parents
provide a supportive atmosphere that allows children to achieve self-control
without the loss of self-esteem, children gain a sense of autonomy. In con-
trast, if children are subjected to severe punishment or ridicule, they may
come to doubt their abilities or to feel a general sense of shame.
3. Initiative Versus Guilt (ages 4 to 6). Like Freud, Erikson saw the time between
ages 4 and 6 years as a period during which children come to identify with,
and learn from, their parents: “[The child] hitches his wagon to nothing less
than a star: he wants to be like his parents, who to him appear very pow-
erful and very beautiful” (Erikson, 1959/1994). The child in this third stage
of development is constantly setting goals (building a high tower of blocks,
learning the alphabet) and working to achieve them. Like Freud, Erikson
believed that a crucial attainment is the development of conscience—the
internalization of the parents’ rules and standards, and the experiencing of
guilt when failing to uphold them. The challenge for the child is to achieve a
balance between initiative and guilt. If parents are not highly controlling or
punitive, children can develop high standards and the initiative to meet them
without being crushed by worry about not being able to measure up.
4. Industry Versus Inferiority (age 6 to puberty). Erikson’s fourth stage, which lasts
from age 6 to puberty (Freud’s latency period), is crucial for ego development.
During this stage, children master cognitive and social skills that are impor-
tant in their culture, and they learn to work industriously and to cooperate
with peers. Successful experiences give the child a sense of competence, but
failure can lead to excessive feelings of inadequacy or inferiority.
5. Identity Versus Role Confusion (adolescence to early adulthood). Erikson accorded
great importance to adolescence, seeing it as a critical stage for the achieve-
ment of a core sense of identity. Adolescents change so rapidly in so many
Many parents witness scenes like the one
depicted here. Should this toddler be made
to feel shame for his natural exploratory
behavior?
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ways that they can hardly recognize themselves, either in the mirror or in
their minds. The dramatic physical changes of puberty and the emergence
of strong sexual urges are accompanied by new social pressures, including a
need to make educational and occupational decisions. Caught between their
past identity as a child and the many options and uncertainties of their future,
adolescents must resolve the question of who they really are or live in confu-
sion about what roles they should play as adults. As you will see in Chapter
11, developmental scientists have devoted a good deal of attention to the
stage of identity versus role confusion in modern multicultural societies.
Current Perspectives
The most significant of Freud’s contributions to developmental psychology were
his emphasis on the importance of early experience and emotional relationships
and his recognition of the role of subjective experience and unconscious mental
activity. Erikson’s emphasis on the quest for identity in adolescence has had a last-
ing impact, providing the foundation for a wealth of research on this aspect of ado-
lescence. The signal weakness of both theories is that their major theoretical claims
are stated too vaguely to be testable, and many of their specific elements, particu-
larly in Freud’s theory, are generally regarded as highly questionable. Nevertheless,
there is no doubt that Freud’s theory has been enormously influential. Further-
more, in recent years, some of Freud’s and Erikson’s original ideas have reemerged
in modified form in psychological research and thinking.
Freud’s identification of infantile amnesia, for example, has been supported by
a vast literature on the earliest memories that people can recall (Bauer, Wenner, &
Kroupina, 2002; Hayne, 2004; Neisser, 2004). Freud was correct in noting that few
of us have conscious memories of our experiences from our first few years. How-
ever, although the precise reasons for the absence of autobiographical memory in
the first three years are unknown, virtually no one thinks it is due to repression, as
Freud claimed.
Erikson’s psychosocial stages of development have also received some support
from research on autobiographical memory. In one study, adults between the ages
of 62 and 89 were asked to recall up to three memories from each decade of their
lives, and the researchers classified their reports with respect
to Erikson’s stages (Conway & Holmes, 2004). The reported
memories of these older adults corresponded quite well with
Erikson’s stages. For example, memories from the second de-
cade of their lives were predominantly of experiences having to
do with identity confusion and establishing a sense of identity.
Freud’s emphasis on the importance of early experience
and close relationships was especially influential in setting the
foundation for modern-day attachment theory and research
(which you will read about in Chapter 11). The research in
this area strongly suggests that the nature of infants’ relation-
ships with their parents not only affects behavior in infancy
but also has important long-term effects on close relationships
throughout life (Allen et al., 2004; Kobak, Cassidy, & Ziv,
2004; Main, 2000).
In addition, Freud’s remarkable insight that much of our men-
tal life occurs outside the realm of consciousness is fundamental
the vast abundance of cartoons about Freud
and psychoanalysis testifies to his enormous
impact on society.
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“To this day, I can hear my mother’s voice—harsh, accusing, ‘Lost your
mittens? You naughty kittens! Then you shall have no pie!’”

348 n chapter 9 THEORIES Of SOCIAL DEvELOPMENT
to modern cognitive psychology and brain science. Indeed, current research in cogni-
tive and affective neuroscience suggests that a remarkably large proportion of human
behavior stems from unconscious processes. According to this research, we are, to a
surprising degree, “strangers to ourselves,” often acting on the basis of unconscious
processes and only later constructing rational accounts of our behavior (T. D. Wilson,
2002). In this sense, we experience the “illusion of conscious will,” believing that our
thoughts are the basis for our behavior, even though those thoughts often come after
the brain has already initiated the behavior (Wegner, 2002). Many of us cry out and
jump back even before we are aware that there is a snake across our path (Öhman &
Mineka, 2001).
Our behavior is also influenced by implicit attitudes of which we are unaware,
attitudes that are often antithetical to what we consciously believe. For example,
many individuals who believe that they lack racial prejudice nevertheless uncon-
sciously associate members of some racial groups with a variety of negative char-
acteristics (Greenwald & Banaji, 1995; Nosek & Banaji, 2009). Even children as
young as 6 years of age exhibit implicit racial biases (Baron & Banaji, 2006). To
experience this phenomenon first hand, visit http://implicit.harvard.edu/implicit
and take the Implicit Attitudes Test: the result may surprise you (although it would
probably not have surprised Freud).
How might psychoanalytic theories be useful to Kismet’s designers? They have
already adopted the goal of making Kismet as sociable as possible. Probably the
most important further step they can take, based on Freud’s and Erikson’s theories,
is to program Kismet to form a few very close relationships with others. Certain
people should become much more important to Kismet than other people with
whom it interacts. Ideally, Kismet should derive some sense of security and well-
being from those relationships. Furthermore, those relationships should have a last-
ing effect on Kismet’s internal organization so that they continue to influence the
robot throughout its “life.”
review:
The psychoanalytic theories of Sigmund Freud and Erik Erikson propose that social and emo-
tional development proceeds in a series of stages, with each stage characterized by a par-
ticular task or crisis that must be resolved for subsequent healthy development. A healthy
personality involves an appropriate balance between the three structures of personality—id,
ego, and superego. Maturational factors play a key role in both theories. Psychic energy and
sexual impulses are emphasized by Freud as major forces in development, whereas Erikson
places greater emphasis on social factors. Both theories maintain that early experiences in
the context of the family have a lasting effect on the individual’s relationships with other peo-
ple. These theories have had enormous, continuing impact on Western thought and culture.
Learning Theories
I imagine the mind of children as easily turned this or that way, as water itself.
—John Locke
As you may recall from Chapter 1, the empiricist philosopher John Locke believed
that experience shapes the nature of the human mind. The intellectual descendants
of Locke are psychologists who consider learning from experience to be the pri-
mary factor in social and personality development.

http://implicit.harvard.edu/implicit

L E A R N I N G T H E O R I E S n 349
View of Children’s Nature
In contrast to Freud’s emphasis on the role of internal forces and subjective experi-
ence, most learning theorists have emphasized the role of external factors in shap-
ing personality and social behavior. They have often made very bold claims about
the extent to which development can be guided by how people reward, or reinforce,
certain of children’s behaviors and punish or ignore others. More contemporary
learning theorists have emphasized the importance of cognitive factors and the
active role children play in their own development.
Central Developmental Issues
The primary developmental question on which learning theories take a unani-
mous stand is that of continuity/discontinuity: they all emphasize continuity, pro-
posing that the same principles control learning and behavior throughout life
and that therefore there are no qualitatively different stages in development. Like
information- processing theorists, learning theorists focus on the role of specific
mechanisms of change—which, in their view, involve learning principles, such as rein-
forcement and observational learning. They believe that children become different
from one another primarily because they have different histories of reinforcement
and learning opportunities. The theme of research and children’s welfare is also rel-
evant here in that therapeutic approaches based on learning principles have been
widely used to treat children with a variety of problems.
Watson’s Behaviorism
John B. Watson (1878–1958), the founder of behaviorism, believed that children’s
development is determined by their social environment and that learning through
conditioning is the primary mechanism of development (see Chapter 5, pages 201–
202). He also believed that psychologists should study only objectively verifiable
behavior, not the “mind.”
The extent of Watson’s (1924) faith in the power of conditioning is clear in his
famous boast:
Give me a dozen healthy infants, well-formed, and my own specified world to bring
them up in, and I’ll guarantee to take any one at random and train him to become
any type of specialist I might select—doctor, lawyer, artist, merchant-chief, and yes,
even beggar man and thief, regardless of his talents, penchants, tendencies, abilities,
vocations, and race of his ancestors.
(p. 104)
On a much less ambitious scale, Watson demonstrated the power
of classical conditioning in a famous—and by present standards,
unethical—experiment with a 9-month-old infant referred to as
“Little Albert” (Watson & Rayner, 1920). Watson first exposed Little
Albert to a perfectly nice white rat in the laboratory. Initially, Albert
reacted positively to the rat. On subsequent exposures, however, the
researchers repeatedly paired the presentation of the rat with a loud
noise that clearly frightened Albert. After a number of such pairings,
Albert became afraid of the rat itself.
Our everyday lives are filled with examples of conditioned
responses. Infants and young children, for example, often show fear
at the sight of a doctor or nurse in a white coat, based on their pre-
vious association between people wearing white coats and painful
to demonstrate the power of conditioning,
John B. Watson and his assistant rosemary
raynor conditioned “Little albert” to fear a
white rat. albert had not been afraid of the
rat until its presentation was paired several
times with a loud, frightening sound.
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350 n chapter 9 THEORIES Of SOCIAL DEvELOPMENT
injections. (To counteract this problem, modern pediatricians often sport lab
coats with cheerful designs, hoping to elicit a positive response in their young
patients.)
Watson’s work on classical conditioning laid the foundation for treatment proce-
dures that are based on the opposite process—the deconditioning, or elimination, of
fear. A student of Watson’s (M. C. Jones, 1924) treated 2-year-old Peter, who was
deathly afraid of white rabbits (as well as white rats, white fur coats, white feathers,
and a variety of other white things). To decondition Peter’s fear, the experimenter
first gave him a favorite snack. Then, as Peter ate, a white rabbit in a cage was very
slowly brought closer and closer to him—but never close enough to make him
afraid. After repeatedly being exposed to the feared object in a context that was
free of distress and provided the positive experience of a snack, Peter got over his
fear. Eventually, he was even able to pet the rabbit. This approach, now known as
systematic desensitization, is still widely used to rid people of fears and phobias
of everything from dogs to dentists.
Believing that he had established the power of learning in development, Watson
placed the responsibility for guiding children’s development squarely on the shoul-
ders of their parents. In his child-rearing manual, Psychological Care of Infant and
Child (1928), he offered parents stern advice for fulfilling this responsibility. One
particular piece of Watson’s advice that was widely adopted in the United States
was to put infants on a strict feeding schedule. The idea was that the baby would
become conditioned to expect a feeding at regular intervals and therefore would
not cry for attention in between. To help implement this and other of his strict
regimens, Watson advised parents to achieve distance and objectivity in their rela-
tions with their children (just as he exhorted psychologists to be objective in their
research):
Treat them as though they were young adults. Dress them, bathe them with care and
circumspection. Let your behavior always be objective and kindly firm. Never hug
and kiss them, never let them sit on your lap. If you must, kiss them once on the fore-
head when they say good night. Shake hands with them in the morning. Give them
a pat on the head if they have made an extraordinarily good job on a difficult task.
Try it out. In a week’s time you will find how easy it is to be perfectly objective with
your child and at the same time kindly. You will be utterly ashamed of the mawkish,
sentimental way you have been handling it.
(pp. 81–82)
Watson’s overly strict child-rearing advice gradually fell from favor with the
publication and widespread success of Dr. Benjamin Spock’s The Common Sense
Guide to Baby and Child Care, first published in 1946 (Spock’s thinking about early
development and child rearing was very strongly influenced by Freud). However,
Watson’s behaviorist emphasis on the environment as the key factor in determining
behavior persisted in the work of B. F. Skinner.
Skinner’s Operant Conditioning
B. F. Skinner (1904–1990) was just as forceful as Watson in proposing that
behavior is under environmental control, once claiming that “a person does not act
upon the world, the world acts upon him” (Skinner, 1971, p. 211). As described in
Chapter 5, a major tenet of Skinner’s theory of operant conditioning is that we tend
to repeat behaviors that lead to favorable outcomes—that is, reinforcement—and
suppress those that result in unfavorable outcomes—that is, punishment. Skinner
B. F. Skinner, who once appeared in 40th
place in a popular magazine’s list of the 100
most important people who ever lived (p. h.
Miller, 2002), believed that children’s devel-
opment is primarily a matter of their rein-
forcement history.
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systematic desensitization n a form
of therapy based on classical condi-
tioning, in which positive responses are
gradually conditioned to stimuli that ini-
tially elicited a highly negative response.
This approach is especially useful in the
treatment of fears and phobias.

L E A R N I N G T H E O R I E S n 351
believed that everything we do in life—every act—is an operant response influ-
enced by the outcomes of past behavior.
Skinner’s research on the nature and function of reinforcement led to many dis-
coveries, including two that are of particular interest to parents and teachers. One
is the fact that attention can by itself serve as a powerful reinforcer: children often
do things “just to get attention” (Skinner, 1953, p. 78). Thus, the best strategy for
discouraging a child who throws temper tantrums from continuing to do so is to
ignore that behavior whenever it occurs. The popular behavior-management strat-
egy of time-out, or temporary isolation, involves systematically withdrawing atten-
tion and thereby removing the reinforcement for inappropriate behavior, with the
goal of extinguishing it.
When the toddler son of one of the authors first graduated to a “big-boy
bed,” he repeatedly got up after having been put to bed, using one pretext after
another to join his parents. This undesirable behavior was extinguished in just
a few nights by his father, who sat in a chair outside the bedroom door. Every
time the child appeared, his father gently, but firmly and silently, put him back
in his bed. The key to this successful intervention was the fact that there was no
reinforcement for getting out of bed—no talking, no yelling, no drink of water,
no interaction of any sort—in short, none of the potent reinforcers that parental
attention provides.
A second important discovery that Skinner made is the great difficulty of ex-
tinguishing behavior that has been intermittently reinforced, that is, that has some-
times been followed by reward and sometimes not. As Skinner discovered in his
research with animals, intermittent reinforcement makes behaviors resistant to
extinction: if the reward for a behavior is totally withdrawn following intermit-
tent reinforcement, the behavior persists longer than it would if it had previously
been consistently reinforced. In effect, if a given behavior is not rewarded every
time it is performed, an animal is likely to maintain the expectation that the next
performance of the behavior may produce the reward.
Parents often encourage unwanted behavior in their children by inadvertently
applying intermittent reinforcement. They valiantly try not to reward their chil-
dren’s whiny or aggressive demands, but—being human—they
sometimes give in. Such intermittent reinforcement is very power-
ful: if a parent who had occasionally given in to whining never did
so again, the child would nevertheless continue to resort to whin-
ing for a long time, assuming that because it worked in the past,
it might work again. The intermittent-reinforcement effect is one
reason most children have at least a few persistent bad habits. Part
of the effectiveness of the bedtime example described above was
due to the total consistency of the father’s behavior.
Skinner’s work on reinforcement has led to a form of ther-
apy known as behavior modification, which has proven quite
useful for changing undesirable behaviors. A simple example of
this approach involved a preschool child who spent too much of
his time in solitary activities. Observers noticed that the boy’s
teachers were unintentionally reinforcing his withdrawn behav-
ior: they talked to him and comforted him when he was alone
but tended to ignore him when he played with other children.
The boy’s withdrawal was modified by reversing the reinforce-
ment contingencies: the teachers began paying attention to
although scolding has the goal of causing
the child to stop doing something that the
parent disapproves of, the fact that it is also
a form of paying attention to a child may
actually reinforce undesirable behaviors and
cause them to persist.
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intermittent reinforcement n incon-
sistent response to the behavior of
another person, for example, sometimes
punishing an unacceptable behavior and
sometimes ignoring it
behavior modification n a form of
therapy based on principles of operant
conditioning in which reinforcement con-
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more adaptive behavior

352 n chapter 9 THEORIES Of SOCIAL DEvELOPMENT
the boy whenever he joined a group but ignored him whenever he withdrew.
Soon the child was spending most of his time playing with his classmates (F. R.
Harris, Wolf, & Baer, 1967).
Social Learning Theory
Social learning theory, like other learning theories, attempts to account for per-
sonality and other aspects of social development in terms of learning mechanisms.
However, in assessing the influence of the environment on children’s development,
A series of classic studies by Albert Bandura
and his colleagues (Bandura, 1965;
Bandura, Ross, & Ross, 1963) will give you
a good sense of the kind of questions and
methods that typify social learning theory
research. The investigators began by hav-
ing preschool children individually watch
a short film in which an adult model per-
formed highly unusual aggressive actions on
a Bobo doll (an inflatable toy, with a weight
in the bottom so it pops back up as soon
as it is knocked down). The model punched
the doll, hit it with a mallet while shouting
“Sockeroo,” threw balls at it while shout-
ing “Bang bang,” and so on.
In one study, three groups of children
observed the adult model receive different
consequences for these aggressive behaviors.
One group saw the model receive rewards (an
adult gave the model candy and soda and
praised the “championship performance”).
Another group saw the model punished
(scolded). The third group saw the model ex-
perience no consequences. The question was
whether vicarious reinforcement—observing
someone else receive a reward or a punish-
ment—would affect the children’s subse-
quent reproduction of the behavior. After
viewing the film, each child was left alone
in a playroom with a Bobo doll, and hidden
observers recorded whether the child imi-
tated what he or she had seen the model do.
Later, whether or not they had imitated the
model, the children were offered juice and
prizes to reproduce all the model’s actions
that they could remember.
The results are shown in the figure. The
children who had seen the model punished
imitated the behavior less than did those in
the other two groups. However, the children
in all conditions had learned from observ-
ing the model’s behavior and remembered
what they had seen; when offered rewards
to reproduce the aggressive actions, they did
so, even if they had not spontaneously per-
formed them in the initial test.
One particularly interesting feature of
this research is the gender differences
that emerged: boys were more physically
BOX 9.1: a closer look
BANDURA AND BOBO
Boys
Model rewarded
Girls Boys Girls Boys Girls
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No Incentive
Positive Incentive
Model punished No consequences
this chart shows the average number of aggressive behaviors children
imitated after seeing a model rewarded, punished, or receiving no con-
sequences for aggressive behavior. In the no-incentive test, the children
were simply left alone in the room with the Bobo doll and were given no
instructions. In the positive-incentive test, they were offered a reward to
do what they had seen the model do. the results clearly show that the
children had learned from what they observed and that they had learned
more than they initially showed. (adapted from Bandura, 1965)
vicarious reinforcement n observing
someone else receive a reward or
punishment

L E A R N I N G T H E O R I E S n 353
social learning theory emphasizes observation and imitation, rather than reinforce-
ment, as the primary mechanisms of development. Albert Bandura (1977, 1986),
for example, has argued that most human learning is inherently social in nature and
is based on observation of the behavior of other people. Children learn rapidly and
efficiently simply from watching what other people do and then imitating them.
Although direct reinforcement can increase the likelihood of imitation, it is not
necessary for learning. Children can learn from symbolic models, that is, from read-
ing books and from watching TV or movies, in the absence of any reinforcement
for their behavior (see Box 9.1).
aggressive toward the Bobo doll than girls
were. However, the girls had learned as much
about the modeled behaviors as the boys
had, as shown by their increased level of im-
itation when offered a reward. Presumably,
boys and girls generally learn a great deal
about the behaviors considered appropriate
to both genders but inhibit those they believe
to be inappropriate for their own gender.
This classic research thus demonstrates
that children can quickly acquire new behav-
iors simply as a result of observing others,
that their tendency to reproduce what they
have learned depends on whether the person
whose actions they observed was rewarded or
punished, and that what children learn from
watching others is not necessarily evident in
their behavior.
these photographs show an adult
performing a series of aggres-
sive actions on a Bobo doll. the
boy who had observed the adult’s
behavior subsequently imitated it
when left alone in the room with
the Bobo doll. the girl, who did
not initially reproduce the mod-
el’s aggressive actions, did imi-
tate the model’s behavior when
offered a reward to do so.
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354 n chapter 9 THEORIES Of SOCIAL DEvELOPMENT
Over time, Bandura increasingly emphasized the cognitive aspects of observa-
tional learning, eventually renaming his view “social cognitive theory.” Obser-
vational learning clearly depends on basic cognitive processes of attention to
others’ behavior, encoding what is observed, storing the information in memory, and
retrieving it at some later time in order to reproduce the behavior observed earlier.
Thanks to observational learning, many young children know quite a bit about
adult activities—such as driving a car (you insert and turn the ignition key, press
on the accelerator, turn the steering wheel)—long before being allowed to engage
in them themselves.
Unlike most learning theorists, Bandura emphasized the active role of children
in their own development, describing development as a reciprocal determinism
between children and their social environment. The basic idea of this concept is
that every child has characteristics that lead him or her to seek particular kinds of
interactions with the external world. The child is affected by these interactions in
ways that influence the kinds of interactions he or she seeks in the future. The con-
cept is illustrated in Figure 9.1, which depicts how a child’s aggressive tendencies
can have an impact on the child’s playmates and, in turn, be shaped by how those
playmates respond.
Bandura has also emphasized the importance of a cognitive factor he calls
perceived self-efficacy—a person’s beliefs about how effectively he or she can
control his or her own behavior, thoughts, and emotions in order to achieve a
desired goal (Bandura, 1997; Bandura et al., 2003). For example, your perceived
self-efficacy for affect regulation has to do with your beliefs about how well you can
manage your emotional life. In terms of positive affect, your perceived self-efficacy
includes your sense of your ability to express affection for another person and to
feel satisfaction with your accomplishments. In terms of negative affect, it includes
how well you think you can manage fear or anger in the face of threats and provo-
cations and calm yourself after being upset. Perceived academic self-efficacy con-
cerns students’ beliefs about how well they can regulate their learning activities,
master their coursework, and fulfill their own and others’ expectations. A person
with high academic self-efficacy tends, for example, to arrange the environment
to be conducive to effective studying and, when necessary, to seek information and
help from teachers, parents, and peers.
An individual’s perceptions of self-efficacy in various domains often operate in
concert (Bandura et al., 2003). For example, adolescents with low self-efficacy for
a good example of observational learning. ©
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reciprocal determinism n Bandura’s
concept that child–environment influ-
ences operate in both directions; chil-
dren are affected by aspects of their
environment, but they also influence the
environment
perceived self-efficacy n an individ-
ual’s beliefs about how effectively he or
she can control his or her own behavior,
thoughts, and emotions in order to
achieve a desired goal

L E A R N I N G T H E O R I E S n 355
affect regulation tend to also have low self-efficacy with respect to managing their
academic performance. In other words, students who lack confidence in their abil-
ity to regulate their emotional life see themselves as incapable of taking charge of
their academic work. They are also more likely to engage in delinquent behavior
(lying, cheating, theft, aggression, and so forth), presumably because feeling inca-
pable of regulating their own behavior undermines their ability to resist negative
peer pressures.
Current Perspectives
In contrast to psychoanalytic theories, learning theories are based on principles
derived from experiments. As a result, they allow explicit predictions that can be
empirically tested. Partly for this reason, they have inspired an enormous amount
of research yielding a great deal of understanding about parental socialization prac-
tices and how children learn social behaviors in many domains. They have also
led to important practical applications, including clinical procedures of systematic
desensitization and behavior modification. The primary weakness of the learning
approach is its lack of attention to biological influences and, except for Bandura’s
theory, to the role of cognition in influencing behavior.
Kismet’s designers took learning theories of development to heart from the very
beginning by giving the robot the crucial capacity for learning that is mediated
by humans. The emotional and verbal reactions of people to its behaviors instruct
Kismet regarding the appropriateness of what it has done. Kismet also has the
capacity to acquire new behaviors by modeling what it “sees” and “hears” humans
do. Kismet’s ability to learn from people is a crucial aspect of what makes it seem
truly sociable. What would it take for Kismet to acquire a sense of what Bandura
refers to as perceived self-efficacy? Could Kismet ever form “beliefs” about what it
can and cannot do and base its behavior on those beliefs?
Child’s Behavior Social Environment
Child enjoys playing violent video games
Child encourages peers to begin
playing violent games together
Child and other peer group
members encourage one another to
play increasingly violent games
Child and other group members
become desensitized to violence in
games
Child and other group members
encourage each other to behave
more aggressively in general
Interacting with peers, child plays
violent games more and more often
Child’s increasing skill leads to greater
enjoyment of violent games and to
spending more time with the group and
less time with other friends
Child becomes desensitized to
aggression in other contexts and
becomes less empathic
Child becomes more aggressive with
peers, leading to rejection by nongroup
members and further commitment to
the violent-games group
FIGURE 9.1 reciprocal determinism
this chart depicts a hypothetical example
showing how a child both influences and
is influenced by the social environment.
(Based on data from c. a. anderson &
Bushman, 2001)

356 n chapter 9 THEORIES Of SOCIAL DEvELOPMENT
review:
Learning theorists assume that social development is primarily attributable to what chil-
dren learn through their interactions with other people. Early behaviorists such as Watson
and Skinner emphasized the reinforcement history of the individual, believing that children’s
social behavior is shaped by the pattern of rewards and punishments they receive from others.
Social learning theorists, most prominently Albert Bandura, emphasize the role of cognition
in social learning, noting that children learn a great deal simply from observing the behavior
of other people, including the ramifications of observed behavior (such as the rewards and
punishments observed in the Bobo doll experiments described in Box 9.1). Perceived self-
efficacy affects the behavior of children in many ways, including how well they think they
can manage their emotions and schoolwork. Learning approaches have inspired a variety of
treatment methods useful for a wide range of behavioral problems in children.
Theories of Social Cognition
Developmental theories of social cognition have to do with children’s ability to
think and reason about their own and other people’s thoughts, feelings, motives,
and behaviors. Like adults, children are active processors of social information.
They pay attention to what other people do and say, and they are constantly draw-
ing inferences, forming interpretations, constructing explanations, or making
attributions regarding what they observe. They process information about their
own behavior and experiences in the same way.
The complexity of children’s thinking and reasoning about the social world is
related to, and limited by, the complexity of their thought processes in general.
After all, the same mind that solves arithmetic and conservation problems also
solves problems having to do with making friends and resolving moral dilemmas.
With advances in cognitive development in general, the way that children think
about themselves and other people deepens and becomes more abstract.
View of Children’s Nature
Social cognitive theories provide a sharp contrast to the emphasis that psycho-
analytic and learning theories place on external forces as the primary source of
development. Instead, social cognitive theories emphasize the process of self-
socialization—children’s active shaping of their own development. According to
this view, children’s knowledge and beliefs about themselves and other people lead
them to adopt particular goals and standards to guide their own behavior.
Central Developmental Issues
The central theme of most relevance to social cognitive theories is the active
child. Another prominent theme is individual differences, particularly in the com-
parisons that are often drawn between the thinking and behavior of males and
females, aggressive and nonaggressive children, and so on. The issue of continuity/
discontinuity is important in some prominent stage theories that emphasize
age-related qualitative changes in how children think about the social world.
Information-processing theories, on the other hand, stress continuity in the pro-
cesses involved in social reasoning. In the following discussions, we will con-
sider these two types of social cognitive theories. The first type is represented by
self-socialization n the idea that chil-
dren play a very active role in their own
socialization through their activity prefer-
ences, friendship choices, and so on

T H E O R I E S O f S O C I A L C O G N I T I O N n 357
Selman’s stage theory of role taking; the second type is represented by Dodge’s
information-processing theory of social problem solving and by Dweck’s attribu-
tional account of academic achievement.
Selman’s Stage Theory of Role Taking
In formulating his theory of social cognition, Robert Selman (1980; Yeates &
Selman, 1989) focused on the development of role taking—the ability to adopt
the perspective of another person, to think about something from another’s point
of view. He proposed that such role taking is essential to understanding another
person’s thoughts, feelings, or motives.
According to Selman, young children’s social cognition is quite limited because
they lack the ability to engage in role-taking behavior. Indeed, Selman, like Piaget,
suggested that before the age of 6 years, children are virtually unaware that there is
any perspective other than their own; they assume that whatever they think, others
will think as well. Perhaps failure to recognize the discrepant view of someone else
underlies those endless sibling arguments of the familiar form “ ‘Did so,’ ‘Did not,’
‘Did so,’ ‘Did not.’ ”
Selman proposed that children go through four increasingly
complex and abstract stages in their thinking about other peo-
ple. In stage 1 (roughly ages 6 to 8), children come to appreci-
ate that someone else can have a perspective different from their
own, but they assume that the different perspective is merely
due to that person’s not possessing the same information they
do. In stage 2 (ages 8 to 10), children not only realize that some-
one else can have a different view, but they also are able to think
about the other person’s point of view. However, it is not until
stage 3 (ages 10 to 12) that children can systematically com-
pare their own and another person’s point of view. In this stage,
they can also take the perspective of a third party and assess
the points of view of two other people. In stage 4 (age 12 and
older), adolescents attempt to understand another’s perspec-
tive by comparing it with that of a “generalized other,” assessing
whether the person’s view is the same as that of most people in
their social group.
Notice that in Selman’s stages of role taking, as chil-
dren become less egocentric in their reasoning, they become
increasingly capable of considering multiple perspectives simul-
taneously (e.g., their own, another person’s, and “most people’s”).
This growth in social cognition mirrors the cognitive changes identified by Piaget
(and discussed in Chapter 4). Not surprisingly, children’s progress through Selman’s
stages of role taking is strongly related to their progress through Piaget’s stages
(Keating & Clark, 1980).
Dodge’s Information-Processing Theory of Social
Problem Solving
The information-processing approach to social cognition emphasizes the cru-
cial role of cognitive processes in social behavior. This approach is exemplified
by Dodge’s analysis of children’s use of aggression as a problem-solving strat-
egy (Dodge, 1986; Dodge, Dishion, & Lansford, 2007). In the research that
Many of young children’s arguments with
others stem from their difficulty appreci-
ating that another person can have a dif-
ferent point of view from their own.
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role taking n being aware of the per-
spective of another person, thereby better
understanding that person’s behavior,
thoughts, and feelings

358 n chapter 9 THEORIES Of SOCIAL DEvELOPMENT
originally motivated Dodge’s theory, children were presented
stories that involved a child who suffers because of another
child’s actions, the intentions of which are ambiguous. For
example, in one story, as a child is working hard to assemble a
puzzle, a peer bumps into the table, scattering the puzzle pieces,
and merely says “Oops.” The children were then asked to imag-
ine themselves as the victim in this scenario and to describe
what they would do and why. Some children interpreted the
other child’s knocking into the table as an accident and said that
they would simply ignore the event. Others concluded that the
peer bumped the table on purpose, and they reported that they
would find a way to get even (many thought that punching the
offender would be a good way to achieve that goal).
Dodge and his colleagues have found that some children have a
hostile attributional bias, that is, a general expectation that oth-
ers are antagonistic to them (Crick & Dodge, 1994; S. Graham &
Hudley, 1994). This bias leads such children to search for evidence
of hostile intent on the part of the peer in the above scenario and
to attribute to the peer a desire to harm them. They are likely to conclude that retali-
ation is the appropriate response to the peer’s behavior. Hostile attributional biases
become self-fulfilling prophecies: a child’s aggressive retaliation to the presumed hos-
tile act of a peer elicits counterattacks and rejection by his or her peers, further fuel-
ing the child’s belief in the hostility of others.
School systems have particular problems in dealing with children who have a
hostile attributional bias. One strategy is to remove them from regular classrooms
because of their disruptive behavior and put them into special classrooms in which
they can be more closely supervised (Dodge, Lansford, & Dishion, 2007). How-
ever, this approach brings together children with hostile attributional biases, caus-
ing other negative consequences. First, it provides these youngsters with evidence
supporting their existing expectation of hostility from others, raising the possibil-
ity that they will reinforce one another’s aggressive tendencies. At the same time, it
segregates them from more well-adjusted peers from whom they might learn more
moderate attitudes and social strategies.
There are many reasons why a child might develop a hostile attributional bias.
However, it is noteworthy that children who have been physically abused are par-
ticularly likely to attribute anger to others, even in neutral situations (Pollak et al.,
2000). It may be that the experience of physical abuse leads children to be espe-
cially sensitive to cues to anger. For example, physically abused children are better
at recognizing angry facial expressions than are children who have not experienced
abuse, and the speed with which they do so is related to the degree of anger and
hostility to which they have been subjected (as reported by their parent) (Pollak et
al., 2009). Physically abused children also have difficulty reasoning about negative
emotions. In one study, abused children had difficulty determining which situa-
tions might trigger anger in parents, endorsing both positive and negative events as
potential causes of parental anger (Perlman et al., 2008). For example, when pre-
sented hypothetical stories about child–parent situations, the abused children saw
anger as a plausible response to positive events, such as a child’s winning a prize at
school or helping around the house. A tendency to assume anger in others (even
when it is not present), paired with difficulty understanding what might provoke
anger in others, is likely to result in a hostile attributional bias. (We will examine
child abuse in more detail later in the chapter.)
the boy who was spilled on by the other
boy seems to have a hostile attributional
bias. Because he readily assumes that other
people have the intent to harm him, he attri-
butes a hostile intention to the other boy.
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theory, the tendency to assume that other
people’s ambiguous actions stem from a
hostile intent

T H E O R I E S O f S O C I A L C O G N I T I O N n 359
Dweck’s Theory of Self-Attributions and
Achievement Motivation
Imagine two grade-school children, Diane and Megan, both hard at work trying to
solve math problems, and both initially failing. Coming to the realization that the
problems are quite difficult, Diane feels excited about meeting the challenge and
works persistently to get the answers. Megan, in contrast, feels anxious and makes
only a half-hearted effort to solve the problems. What explains this difference in
the children’s reaction to failure?
According to Carol Dweck’s social cognition perspective (2006), the
difference in their reaction is attributable to a difference in their achievement
motivation—that is, in whether they are motivated by learning goals, seeking to im-
prove their competence and master new material, or by performance goals, seeking to
receive positive assessments of their competence or to avoid negative assessments.
From this perspective, Diane has an incremental view of intelligence, the belief that
intelligence can be developed through effort. She focuses on mastery—on meet-
ing challenges and overcoming failures, and she generally expects her efforts to be
successful. Indeed, her increased effort and persistence following failure will in all
likelihood improve her subsequent performance.
Megan, on the other hand, has an entity view of intelligence, the belief that her
intelligence is fixed. Her goal is to be successful, and as long as she is succeeding, all
is well. However, when she fails at something, she feels “helpless.” Not succeeding
causes her to feel bad and doubt her abilities and self-worth.
Underlying these two patterns of achievement motivation are differences in
what attributions children make about themselves, particularly with regard to their
sense of their self-worth. Children with an entity/helpless orientation tend to
base their sense of self-worth on the approval they receive (or do not receive) from
other people about their intelligence, talents, and personal qualities. To feel good
about themselves, they seek out situations in which they can be assured of success
and receive praise, and they avoid situations in which they might be criticized. In
contrast, the self-esteem of children with an incremental/mastery orientation is
based more on their own effort and learning and not on how others evaluate them.
Because they do not equate failure on a task with a personal flaw, they can enjoy the
challenge of a hard problem and persist in the attempt to solve it.
These different motivation patterns are evident as early as preschool (Smiley &
Dweck, 1994). Given a choice of working on a puzzle they have already solved or
on one they had previously failed to solve, some 4- and 5-year-old children strongly
prefer the one they already know how to do, whereas others want to continue work-
ing on the one they had failed to solve.
Older children’s cognitions about themselves and their abilities follow a similar
pattern but involve more complex concepts and reasoning than those of younger
children. Some have what Dweck and her colleagues (Cain & Dweck, 1995;
Dweck, 1999; Dweck & Leggett, 1988) refer to as an entity theory of intelligence.
This theory, like Megan’s entity view of intelligence, is rooted in the idea that a
person’s level of intelligence is fixed and unchangeable. Over time, it comes to
include the belief that success or failure in academic situations depends on how
smart one is. When evaluating their own performance, children with an entity the-
ory of intelligence focus on outcomes—success or failure—not on effort or learn-
ing from mistakes. Thus, when they experience failure (as everyone does some of
the time), they think they are not very smart and that there is nothing they can do
about it. They feel helpless.
achievement motivation n refers
to whether children are motivated by
learning goals, seeking to improve their
competence and master new material, or
by performance goals, seeking to receive
positive assessments of their competence
or to avoid negative assessments
entity/helpless orientation n a gen-
eral tendency to attribute success and
failure to enduring aspects of the self and
to give up in the face of failure
incremental/mastery orientation n a
general tendency to attribute success and
failure to the amount of effort expended
and to persist in the face of failure
entity theory n a theory that a per-
son’s level of intelligence is fixed and
unchangeable

360 n chapter 9 THEORIES Of SOCIAL DEvELOPMENT
Other children subscribe to an incremental theory
of intelligence. This theory, like Diane’s view of intelli-
gence, is rooted in the idea that intelligence can grow as a
function of experience. Children who hold an incremen-
tal theory of intelligence believe that academic success is
achievable through effort and persistence. When evalu-
ating their performance, they focus on what they have
learned, even when they have failed, and they believe that
they can do better in the future by trying harder. They feel
hopeful.
Given what you have just read, what kind of praise and
criticism do you think would reinforce these two patterns?
The answer depends on the focus of the feedback. An
incremental/mastery pattern is reinforced by focusing on
children’s effort, praising them for a good effort (“You
really worked hard on that,” “I like the way you kept at it”)
and criticizing them for an inadequate one (“Next time
you need to put in some more work,” “I think you can do
better if you try harder”). In contrast, an entity/helpless
pattern is reinforced by both praise and criticism focused
on children’s enduring traits or on the child as a whole (“You’re very smart at these
problems. I’m proud of you,” “You just can’t do math. I’m disappointed in you”).
Do these two different types of internal theories have real-world ramifica-
tions? Much of the research on this question has been carried out in the domain
of math education. In an important study conducted in the New York City public
schools, Dweck and her colleagues found that 7th-graders with an incremental
theory of intelligence showed an upward trajectory in math scores over the next 2
years, while the scores of 7th-graders with a fixed theory of intelligence remained
flat (Blackwell, Trzesniewski, & Dweck, 2007). The investigators then provided
an 8-session intervention to a new group of 7th-graders who had a fixed the-
ory of intelligence. Students in this group were taught an incremental theory of
intelligence based on some of the same concepts from basic neuroscience that you
read about in Chapter 3: the brain is plastic and always changing; learning forges
new connections among synapses; and so on. A control group received training in
basic study skills. Remarkably, the children who received the intervention showed
a positive change in motivation as well as improvements in grades, while the chil-
dren in the control group showed a decline in grades.
Another important issue is whether these two types of internal views—entity
theories and incremental theories—have implications for children’s development
in domains beyond intelligence and academic achievement. Recent research by
Yeager and colleagues (2013) suggests that they do. For example, recall the hos-
tile attributional bias discussed in the previous section. Adolescents who maintain
an entity theory about personality traits are more likely to demonstrate a hostile
attributional bias than are adolescents who endorse an incremental theory. In other
words, if they hold the view that people’s behaviors are due to fixed personality
traits (some people are good, others are bad), rather than due to situations or cir-
cumstances, they are more likely to interpret other people’s harmful behavior as
hostile rather than as accidental or situational. Assuming that this is the case, then
learning to take a more incremental view should diminish their tendency to make
hostile attributions. And indeed, this is the case: when the experimenters used
an intervention (which included a brief introduction to neuroscience concepts, as
the comments this teacher is offering his
student on her work could be either benefi-
cial or detrimental, depending on whether
he focuses on how smart she is or on the
effort she has made.
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T H E O R I E S O f S O C I A L C O G N I T I O N n 361
described in the previous paragraph, but nothing about hostile intent) to shift ado-
lescents’ perspectives away from the fixed-entity view and closer to the incremental
view, there was a reduction in the participants’ hostile attributions. Thus, inter-
nal theories about traits of self and others have important implications for diverse
aspects of development.
Where might these individual differences in internal theories come from?
One obvious source is parents, who often try very hard to enhance their child’s
self- esteem. Unfortunately, doing something that might seem purely positive—
praising a child for being good at something—can actually undermine the child’s
motivation for improvement. Another obvious source is teachers. One recent study
showed that the way teachers comfort poor-performing students when the teacher
has an entity perspective (as seen in teacher comments like “It’s okay; not every-
one can be good at math”) can seriously undermine their students’ motivation
and self-expectations (Rattan, Good, & Dweck, 2012). Parents and teachers alike
should be aware that some kinds of praise and comfort are beneficial, whereas
others are not.
Current Perspectives
Social cognitive theorists have made several important contributions to the study
of social development. One is their strong emphasis on children as active seekers
of information about the social world. Another contribution is the insight that the
effect of children’s social experience depends on their interpretation of those expe-
riences. Thus, children who make different attributions about a given social event
(such as someone’s causing them harm) or an academic event (such as doing poorly
on a test) will respond differently to that event. In addition, a large amount of
research has supported the social cognitive position. Although these theories have
provided a very healthy antidote to social theories that left children’s cognition out
of the picture, they too provide an incomplete account. Most notably, they have
very little to say about biological factors in social development.
Kismet is designed to shape his own development through his understanding of
the behavior of humans toward him—a form of self-socialization emphasized by
social cognition theorists. What would it take, however, for Kismet to go further and
draw inferences about others’ cognitions, feelings, motivations? For example, will it
ever be possible for Kismet to make different attributions about a given behavior,
based on subtle aspects of the social context of its history with a person? Even more
challenging, will Kismet come to know that people can hold points of view differ-
ent from one another and from its own? Finally, can Kismet develop some sense
of self-worth that will affect its attributions about itself? These questions about
Kismet’s potential to mimic social cognition highlight the vast complexity of human
social development and the challenge faced by theorists of social development.
review:
Theories of social cognition stress the role of cognitive processes—attention, knowledge,
interpretation, reasoning, attribution, explanation—in children’s social development. A key
aspect of these theories is an emphasis on the process of self-socialization, through which
children actively shape their own development. Selman’s theory of role taking proposes that
children go through stages in terms of their ability to appreciate that different people can
have different points of view. The information-processing approach taken by Dodge to the

362 n chapter 9 THEORIES Of SOCIAL DEvELOPMENT
study of aggression emphasizes the role of children’s interpretation of other people’s behavior.
Aggressive children often have a hostile attributional bias, a general expectation that other
people will be hostile to them. According to Dweck’s theory of achievement motivation, chil-
dren’s response to their success or failure in an academic situation depends on whether they
attribute the outcome to their effort or their intelligence.
Ecological Theories of Development
We now turn to a set of theories united by the fact that they take a very broad view of
the context of social development. Virtually all psychological theories, and certainly
those that we have reviewed in the chapter thus far, emphasize the role of the envi-
ronment in the development of individual children. However, the “environment” in
many of these theories is narrowly construed as immediate contexts—family, peers,
schools. The first two approaches discussed here—ethological and evolutionary psy-
chology views—relate children’s development to the grand context of the evolution-
ary history of our species. The third approach—the bioecological model—considers
multiple levels of environmental influence that simultaneously affect development.
View of Children’s Nature
Ethological and evolutionary theories view children as inheritors of genetically
based abilities and predispositions. The focus of these theories is largely on aspects
of behavior that serve, or once served, an adaptive function.
The bioecological model stresses the effects of context on development, but it
also emphasizes the child’s active role in selecting and influencing those contexts.
Children’s personal characteristics—temperament, intellectual ability, athletic skill,
and so on—lead them to choose certain environments over others, and also influ-
ence the people around them.
Central Developmental Issues
The developmental issue that is front and center in ecological theories is the
interaction of nature and nurture. The importance of the sociocultural context and
the continuity of development are implicitly emphasized in all these theories. The
active role of children in their own development is another central focus, primarily
of the bioecological approach.
Ethological and Evolutionary Theories
Ethological and evolutionary theories are concerned with understanding various
aspects of development and behavior in terms of a given animal’s evolutionary
heritage. Of particular interest are species-specific behaviors—behaviors that are
common to members of a particular species (such as humans) but not typically
observed in other species.
Ethology
Ethology, the study of behavior within an evolutionary context, attempts to under-
stand behavior in terms of its adaptive or survival value. According to ethologists,
a variety of innate behavior patterns in animals were shaped by evolution just as
surely as their physical characteristics were (Crain, 1985).
ethology n the study of the evolutionary
bases of behavior

E C O L O G I C A L T H E O R I E S O f D E v E L O P M E N T n 363
Ethological approaches have frequently been applied to developmental is-
sues. The prototypical, and best-known, example is the study of imprinting made
famous by Konrad Lorenz (1903–1989), who is often referred to as the father of
modern ethology (Lorenz, 1935, 1952). Imprinting is a process by which newborn
birds and mammals of some species become attached to their mother at first sight
and follow her everywhere, a behavior that ensures that the baby will stay near a
source of protection and food. For imprinting to occur, the infant has to encounter
its mother during a specific critical period very early in life.
The basis for imprinting is not actually the baby’s mother per se; rather, the in-
fants of some species are genetically predisposed to follow around the first moving
object with particular characteristics that they see after emerging into the world.
In chickens, for example, imprinting is elicited specifically by the sight of a bird’s
head and neck regions (M. H. Johnson, 1992). Which particular object the indi-
vidual will dutifully trail after is thus a matter of experience-expectant processes
(discussed in Chapter 3, pages 115–116). Usually, the first moving object any chick
sees is its mother, so everything works out just fine.
Although human newborns do not “imprint,” they do have strong tendencies
that draw them to members of their own species. Examples noted in Chapter 5
include an innate visual preference for faces, which seems to result from an attrac-
tion to a face shape with more “stuff ” in the top half. Even though this attraction
is not based on a specific human face template, it gets the infant to pay attention
to the most significant entities in the environment. Also, like other mammals,
human newborns orient to sounds, tastes, and smells familiar from their experi-
ence in the womb—a predisposition that inclines them toward their own mother
(see Chapter 5). One of the most influential applications of ethology to human
development, which we discuss in Chapter 11, is Bowlby’s (1969) extension of the
concept of imprinting to the process by which infants form emotional attachments
to their mother (pages 428–429).
Another example of human behavior to which an ethological perspective has
been applied is the existence of differences in the play preferences of males and fe-
males (which you will read more about in Chapter 15). For example, many (but not
all) boys prefer to play with vehicle toys (trucks and cars, for example), which afford
action play, whereas girls prefer dolls, which are conducive to nurturant play. The
standard accounts for these differences, which come from social learning and social
cognitive theories, maintain that children (especially boys) are encouraged by their
parents to play with “gender-appropriate” toys, and they do so because they want
to be like others of their own sex.
However, some searchers argue that these accounts are not the whole story
and that evolved predispositions fuel these preferences. In one study, for
example, newborn girls looked longer at social stimuli—human faces—than at
nonsocial stimuli such as mobiles, whereas the reverse was true for boys (Connellan
et al., 2001). Similarly, 1-year-old boys watched a video of moving cars for longer
than they watched a video of an active human face, whereas girls did the opposite
(Lutchmaya & Baron-Cohen, 2002).
Evolutionary Psychology
A relatively new branch of psychology that is closely related to ethology is evo-
lutionary psychology, which applies the Darwinian concepts of natural selection
and adaptation to human behavior (Bjorklund, 2007; Geary, 2009). The basic idea
of this approach is that in the evolutionary history of our species, certain genes
imprinting n a form of learning in which
the young of some species of newborn
birds and mammals become attached to
and follow adult members of the species
(usually their mother)
this famous photograph shows Konrad
Lorenz (1952) and a gaggle of greylag
goslings that were imprinted on him and
followed him all over his farm. Lorenz dis-
covered that mallard ducklings are more
discriminating: they would imprint on him
only if he squatted low and dragged himself
around, quacking all the while, for hours on
end. he was a very dedicated scientist.
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364 n chapter 9 THEORIES Of SOCIAL DEvELOPMENT
predisposed individuals to behave in ways that solved the adaptive challenges
they faced (obtaining food, avoiding predators, establishing social bonds), thereby
increasing the likelihood that they would survive, mate, and reproduce, passing
along their genes to their offspring. These adaptive genes became increasingly
common and were passed down to modern humans; thus, many of the ways we
behave today are a legacy from our prehistoric ancestors (Geary, 2009).
One of the most important adaptive features of the human species—
one that clearly distinguishes us from other species—is the large size of
our brains (relative to body size). The trade-off for this is the prolonged
period of immaturity and dependence human children go through. We
are “a slow-developing, big-brained species” (Bjorklund & Pellegrini,
2002), as illustrated in Figure 9.2. In Chapter 2, we discussed how the
size of the human brain at birth is limited by the size of the female pel-
vis. As modern humans evolved, enlargement of our brains was made
possible by birth occurring at a more “premature” stage of development
than is characteristic of other mammals. These evolutionary changes
were made possible by increased social complexity, which is neces-
sary for successful caregiving of extremely helpless offspring. A related
consequence of our large brains and slow development is our species-
typical high level of neural plasticity that supports our unrivaled capac-
ity for learning from experience. Highlighting the adaptive benefits of
our extended immaturity, Bjorklund (1997) has pointed out that
a prolonged period of youth is necessary for humans [who,] more than any other spe-
cies, must survive by their wits; human communities are more complex and diverse
than those of any other species, and this requires that they have not only a flexible in-
telligence to learn the conventions of their societies but also a long time to learn them.
(p. 153, emphasis added)
Many evolutionary theorists have suggested that play, which is one of the
most salient forms of behavior during the period of immaturity of most mam-
mals, is an evolved platform for learning (Bjorklund & Pellegrini, 2002). Children
develop motor skills by racing and wrestling with one another, throwing toy spears,
or kicking a ball into a goal. They try out and practice a variety of social roles (as
mentioned in Chapter 7), enacting what they know about being, say, a parent or a
police officer. One of the main virtues of play is that children can experiment in a
according to evolutionary psychology, gender
differences in play probably have their origin
in the evolutionary history of the human spe-
cies, with males being predisposed to domi-
nance, and females, to nurturing.
T
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0 2 4 6 8 10 12 14
1,300
1,200
1,100
1,000
900
800
700
600
500
400
300
200
100
0
B
ra
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S
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(m
L
)

Juvenile Period in Years
Human
Gorilla
Orangutan
Chimpanzee
Rhesus
Gibbon
Lemur
FIGURE 9.2 Brain sizes of various
primates and humans humans are “a
slow-developing, big-brained species” com-
pared with other primates. the larger the
brain size of various primates, the longer
their developmental period. (adapted from
Bonner, 1988)
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situation with minimal consequences; no one gets hurt if a baby doll is accidentally
dropped on its head or a Nerf gun is fired at a “bad guy.”
To benefit from their protracted immature status, children must, of course, sur-
vive it, and their survival and development require that parents spend an enormous
amount of time, energy, and resources in raising them (Bjorklund, 2007). Why are
parents willing to sacrifice so much for the benefit of their offspring? According
to parental-investment theory (Trivers, 1972), a primary source of motivation for
parents to make such sacrifice is the drive to perpetuate their genes in the human
gene pool, which can happen only if their offspring survive long enough to pass
those genes on to the next generation.
Parental-investment theory also points to a potential dark side of the evolution-
ary picture—the so-called Cinderella effect—which refers to the fact that rates
of child maltreatment are considerably higher for stepparents than for biological
parents. As Figure 9.3 shows, estimates of the rate of murder committed by step-
fathers against children residing with them is hundreds of times higher than the
rate for fathers and their biological children. Furthermore, in families in which
both natural and stepchildren reside, abusive parents typically target their abuse
toward their stepchildren (Daly & Wilson, 1996). Similar findings suggest that
unintended child fatalities (e.g., drowning) are also more likely to occur in homes
with a resident stepparent than in homes with no stepparent, suggesting that there
is less commitment to protecting children in stepparent homes (Tooley et al., 2007).
Although there are clearly many factors that contribute to these patterns, they are
consistent with parent-investment theory; that is, because parenting is so costly, it
is not, from an evolutionary point of view, worth investing in children who cannot
contribute to the perpetuation of one’s own genes.
A clear implication of the evolutionary view of development is that radical de-
partures from the species-typical environment could have negative consequences.
It is well established that exposing young and prenatal animals of various spe-
cies to stimulation that is outside the normal range for their species and age has
adverse effects on their development (e.g., G. Gottlieb, 1992; Kenny & Turkewitz,
1986). For example, while developing inside the egg, bobwhite quails experience
no light or visual stimulation. If a piece of the shell is removed, letting in light
while the embryo develops, the species-typical behavior of the hatchlings is altered,
disrupting normal development (Lickliter, 1995).
Could the same be true for humans? Neonatologist Heideliese Als and
colleagues (2003) believe that we should be concerned about this question with
Age of child (in years)
Genetic fathers Stepfathers
H
om
ic
id
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vi
ct
im
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p
er
m
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p
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n
u
m
500
400
300
200
100
0
500
400
300
200
100
0
0–2 3–5 6–8 9–11 12–14 15–17 0–2 3–5 6–8 9–11 12–14 15–17
FIGURE 9.3 estimated rates
of child homicide committed
by genetic fathers versus step-
fathers in canada from 1974
to 1990 as is shockingly clear,
stepchildren, especially very
young ones, are much more likely
to be murdered by a stepfather
than other children are likely to
be murdered by their biological
fathers. (adapted from Daly &
Wilson, 1996)
parental-investment theory n a
theory that stresses the evolutionary basis
of many aspects of parental behavior,
including the extensive investment par-
ents make in their offspring

366 n chapter 9 THEORIES Of SOCIAL DEvELOPMENT
regard to babies born prematurely. As discussed in Chapter 2, modern medicine
has enabled increasing numbers of premature infants of ever-smaller sizes to sur-
vive. However, their first weeks or even months are spent in an environment that is
radically different from the species-typical fetal environment. Instead of continued
residence in the dark, relatively quiet womb, these babies find themselves in brightly
lit, very noisy intensive- care units. Believing that many of the brain and behavioral
problems common in premature infants may have to do with this atypical early en-
vironment, Als has advocated radical changes in newborn nurseries to simulate the
womb environment, including reducing illumination and noise levels.
A related area of concern about potential negative effects of species-atypical
stimulation is the current craze for providing extra prenatal stimulation that we
discussed in Chapter 2. Our species evolved with a certain amount of stimulation
available to the fetus in utero, and a substantial increase in prenatal stimulation
might very well have negative consequences.
The Bioecological Model
The most encompassing model of the general context of development is Urie
Bronfenbrenner’s bioecological model (Bronfenbrenner, 1979; Bronfenbrenner &
Morris, 1998). Bronfenbrenner conceptualizes the environment as “a set of nested
structures, each inside the next, like a set of Russian dolls” (1979, p. 22). Each
structure represents a different level of influence on development (Figure 9.4).
Embedded in the center of the multiple levels of influences is the individual child,
with his or her particular constellation of characteristics (genes, gender, age, tem-
perament, health, intelligence, physical attractiveness, and so on).
Over the course of development, these individual characteristics interact with
the environmental forces present at each level. The different levels vary in how
immediate their effects are, but Bronfenbrenner emphasizes that every level, from
the intimate context of a child’s nuclear family to the general culture in which the
family lives, has an impact on that child’s development. Note that each of the lev-
els depicted in Figure 9.4 is labeled as a “system,” emphasizing the complexity and
interconnectedness of what goes on in each one. This theory is ecological in the
sense that, just as in the study of the ecology of other living things, it considers how
multiple levels of context influence outcomes. It just happens that instead of the
the environment that premature infants
encounter in a newborn intensive-care unit
is radically different from the uterine envi-
ronment, raising concern that stimulation so
different from anything humans encountered
in the evolutionary past may be detrimental
to development.
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soil microbes or natural predators that might be the relevant ecological contexts
for plants or nonhuman animals, the ecological systems influencing children range
from families to neighborhoods to governments.
The first level in which the child is embedded is the microsystem—the activi-
ties, roles, and relationships in which the child directly participates over time. The
MACROSYSTEM
Broad ideology, laws, and customs
of one’s culture, subculture, or social class
CHRONOSYSTEM
(changes in person
or environment
over time)
EXOSYSTEM
MESOSYSTEM
MICROSYSTEM
Extended
familyFriends of
family
Neighbors
Mass
media
Workplace
Community health
and welfare services
Doctor’s office
Neighborhood
play area
School
Parents and siblings Day-care
centerChurch,
synagogue
Peers
School
board
Legal
services
Tim
e
Child
FIGURE 9.4 the bioecological model Urie Bronfenbrenner considers the child’s environment as
composed of a series of nested structures, including the microsystem (the immediate environment
with which the child directly interacts), the mesosystem (the connections that exist among micro-
systems), the exosystem (social settings that the child is not a part of but that nevertheless affect the
child’s development), and the macrosystem (the general cultural context in which all the other systems
are embedded). this figure illustrates the environment of a child living in the United States. (adapted
from Bronfenbrenner, 1979)
microsystem n in the bioecological
model, the immediate environment that
an individual personally experiences

368 n chapter 9 THEORIES Of SOCIAL DEvELOPMENT
child’s family is a crucial component of the microsystem, and its influence is pre-
dominant in infancy and early childhood. The microsystem becomes richer and
more complex as the child grows older and interacts increasingly often with peers,
teachers, and others in settings such as school, neighborhood, organized sports,
arts, clubs, religious activities, and so on.
Bronfenbrenner stresses the bidirectional nature of all relationships within the mi-
crosystem. For example, the parents’ marital relationship can affect how they treat
their children, and their children’s behavior can, in turn, have an impact on the mari-
tal relationship. A good, supportive marital relationship helps parents interact more
sensitively and effectively with their children (P. A. Cowan, Powell, & Cowan, 1998;
Cox et al., 1989), but a chronically fussy baby can create friction and even damage the
relationship between parents (Belsky, Rosenberger, & Crnic, 1995).
The second level in Bronfenbrenner’s model is the mesosystem, which
encompasses the connections among various microsystems, such as family, peers,
and schools. Supportive relations among these contexts can benefit the child. For
example, children’s academic success is facilitated when their parents value scho-
lastic endeavors and have positive contact with their teachers (Luster & McAdoo,
1996; Stevenson, Chen, & Lee, 1993) and when their peers encourage academic
achievement (Steinberg, Darling, & Fletcher, 1995). When connections in the
mesosystem are nonsupportive, negative outcomes are more likely.
The third level of social context, the exosystem, comprises settings that chil-
dren may not directly be a part of but that can still influence their development.
Their parents’ workplaces, for example, can affect children in many ways, from the
employer’s policies about flexible work hours, parental leave, and on-site child care
to the general atmosphere in which parents work. Parents’ enjoyment or dislike of
their work can affect the emotional relationships within the family (Greenberger,
O’Neil, & Nagel, 1994). Even something as seemingly remote from the child as the
financial success or failure of a parent’s employer can be crucial: job loss, for example,
is related to abusive or neglectful parenting (Emery & Laumann-Billings, 1998).
The outer level of Bronfenbrenner’s model is the macrosystem, which consists
of the general beliefs, values, customs, and laws of the larger society in which all the
other levels are embedded. It includes the general cultural, subcultural, or social-
class groups to which the child belongs. Cultural and class differences permeate
almost every aspect of children’s lives, including differences in beliefs about what
qualities should be fostered in children and how best to foster them.
Cultural influences are apparent even in the earliest memories reported by adults
in different parts of the world. In a cross-cultural study (Q. Wang, 2006), European
Americans reported memories from an earlier age than did Taiwanese participants,
and their memories focused on specific events and their own role in those events.
In contrast, the Taiwanese participants more often described everyday events and
emphasized the role of other people in the recalled events. Presumably, these dif-
ferences reflect cultural values that influence what parents encourage their children
to talk about, especially with respect to the relative value of focusing on oneself or
on others.
Finally, Bronfenbrenner’s model also has a temporal dimension, which he has
referred to as the chronosystem. In any given society, beliefs, values, customs, tech-
nologies, and social circumstances change over time, with consequences for chil-
dren’s development. For example, as a result of technological advances that gave
rise to the “digital age,” children today have access to a vast realm of information
and entertainment unimaginable to previous generations. In addition, the impact
of environmental events depends on another chronological variable—the age of
mesosystem n in the bioecological
model, the interconnections among
immediate, or microsystem, settings
exosystem n in the bioecological model,
environmental settings that a person does
not directly experience but that can affect
the person indirectly
macrosystem n in the bioecological
model, the larger cultural and social con-
text within which the other systems are
embedded
chronosystem n in the bioecological
model, historical changes that influence
the other systems

E C O L O G I C A L T H E O R I E S O f D E v E L O P M E N T n 369
the child. For example, divorce has different effects on toddlers and teens; it may
make both of them unhappy, but young children are more likely to have the extra
burden of thinking that the divorce is their fault (Hetherington & Clingempeel,
1992). Another important aspect of the temporal dimension, which we have noted
on several occasions, is the fact that as children get older, they take an increasingly
active role in their own development, making their own decisions about their
friends, activities, and environments. As Box 9.2 on attention-deficit hyperactivity
disorder (pages 370–371) suggests, the chronosystem can even be a factor in devel-
opmental disorders.
To illustrate the richness of the bioecological model for thinking about and
investigating child development, we will consider three examples in which the
interactions among multiple levels of the model are particularly clear and relevant:
child maltreatment, children and the media, and SES and development.
Child Maltreatment
One of the most serious threats to children’s development in the United States is child
maltreatment, defined as intentional abuse or neglect that endangers the well-being
of anyone younger than 18. In 2011, roughly 681,000 children were confirmed to
be victims of child maltreatment (U.S. Department of Health and Human Services
Administration for Children and Families, 2012). The majority of cases involved
maltreatment by parents, more often mothers. The victims included nearly equal
numbers of girls and boys. The highest rate of victimization was for infants younger
than 1 year: 21.2 out of every 1,000 U.S. infants in this age group were maltreated in
2011. More tragic still, more than 1,500 children—most of them younger than 4—
were killed by a parent or parents. Consistent with the bioecological model, a variety of
factors, including characteristics of the child, the parents, and the community, have
been shown to be involved in the causes and consequences of child abuse.
causes of maltreatment At the level of the microsystem, certain characteristics
of parents increase the risk for maltreatment (Emery & Laumann-Billings, 1998).
Among these are low self-esteem, strong negative reactions to stress, and poor
impulse control. Parental alcohol and drug dependence also increase the probability
child maltreatment n intentional abuse
or neglect that endangers the well-being
of anyone under the age of 18
What different experiences were available to
these girls born in different historical times?
how did their educational and employment
opportunities differ?HU
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370 n chapter 9 THEORIES Of SOCIAL DEvELOPMENT
of maltreatment. So does an abusive spousal relationship: mothers who are abused
by their partner are more likely to abuse their children. In addition, certain charac-
teristics of children—including low birth weight, physical or cognitive challenges,
and difficult temperament—are associated with increased risk for parental abuse
(e.g., Bugental & Happaney, 2004).
Child maltreatment tends to be associated with additional factors in the
mesosystem and exosystem that increase stress on parents. Many of these fac-
tors are related to low family income. They include high levels of unemployment,
inadequate housing, and community violence (Emery & Laumann-Billings, 1998;
Lynch & Cicchetti, 1998).
Many developmental disorders can be prof-
itably examined with the different levels
of the bioecological model in mind. Influ-
ences and interventions from different lev-
els can make it easier or harder for children
to manage the challenges they face. A good
case in point is attention-deficit hyperactivity
disorder (ADHD).
Although the term “ADHD” is relatively
new, the syndrome—variously labeled as
“hyperactivity,” “minimal brain dysfunc-
tion,” and “attention-deficit disorder”
(ADD)—has long been recognized. Children
with ADHD tend to be of normal intelligence
and do not typically show serious emotional
disturbances. However, they have diffi-
culty sticking to plans, following rules and
regulations, and persevering on tasks that
require sustained attention (especially ones
they find uninteresting). Many are hyper-
active, constantly fidgeting, drumming on
their desks, and moving around. Children
with ADHD typically have difficulty acquir-
ing academic skills, such as reading and
writing, since these skills require focus-
ing attention for prolonged periods. Many
also have problems suppressing aggressive
reactions when they are frustrated. All these
symptoms seem to reflect an underlying dif-
ficulty in inhibiting impulses to act (Barkley,
1997). The difficulty is greatest when inter-
esting distractors are present.
An analysis of data collected by the Cen-
ters for Disease Control for 2011–2012 sug-
gests that 6.4 million children aged 4 to 17
received a diagnosis of ADHD at some time
in their life. In other words, roughly 11% of
school-aged children in the United States
today have been given a diagnosis of ADHD.
This represents a 16% increase in ADHD di-
agnoses for this age group since 2007 and
a whopping 41% increase over the past de-
cade. Even more remarkably, 20% of high
school boys have been given a diagnosis of
ADHD at some point in their lives, compared
with 10% of high school girls. This diagnos-
tic differential may be attributable to the fact
that boys with ADHD are more likely than girls
to engage in disruptive behaviors that lead to
their problem being diagnosed (Gaub & Carl-
son, 1997). As with autism spectrum disor-
der (discussed in Chapter 3, page 95), it is
currently unclear whether the steep increase
in rates of diagnosis of ADHD reflects an ac-
tual increase in prevalence, increased aware-
ness of the disorder, changing standards for
ADHD diagnoses, or all of the above.
The causes of ADHD are quite varied.
Genetic factors clearly play a role. If one
identical twin has ADHD, the odds are
about 50% that the other twin does too, a
rate roughly 10 times that among children
in general (Silver, 1999). In addition, ADHD
in adopted children is associated with ADHD
in the biological parent but not in the adop-
tive parent (Rhee et al., 1999). Indeed, her-
itability for ADHD is greater than any other
developmental disorder, with the possible
exception of autism spectrum disorder.
Environmental factors in the microsystem
also influence the development of ADHD.
For instance, prenatal exposure to alcohol,
which can affect brain development (Chap-
ter 2, pages 60–63), is associated with the
development of ADHD (Milberger et al.,
1997). Parents’ behavior toward their chil-
dren may contribute to the early develop-
ment of ADHD, as shown by a large study
with 5-year-olds, half of whom had been of
low birth weight (Tully et al., 2004). Those
low-birth-weight children whose mothers ex-
pressed a high degree of warmth for them
(“He’s my ray of sunshine,” “She’s a de-
light”) were less likely than children of less
warm mothers to show symptoms of ADHD.
However, causal links can be difficult to
determine because, as we have noted on
numerous occasions, developmental risks
tend to cluster together.
Current treatment for ADHD involves
agents in the microsystem (the family doc-
tor), the exosystem (the drug industry),
and the macrosystem (the government).
The most common approach taken by phy-
sicians is to prescribe stimulant medica-
tions, such as Ritalin. Although it seems
paradoxical that stimulants could help chil-
dren who are already overly active, they im-
prove symptoms in 70% to 90% of children
for whom they are prescribed. The reason is
that the brain systems in these children are
actually underaroused; the children’s rest-
less and sometimes disruptive behavior is
actually an attempt to wake the brain up.
Appropriate medication, which stimulates
neurotransmitter systems, allows children
with ADHD to focus their attention better
and to be less distractible. This leads to
BOX 9.2: individual differences
ATTENTION-DEFICIT HYPERACTIVITY DISORDER
attention-deficit hyperactivity
disorder (ADHD) n a syndrome that
involves difficulty in sustaining attention

E C O L O G I C A L T H E O R I E S O f D E v E L O P M E N T n 371
Often a particularly important exosystem contributor to child maltreatment is a
family’s social isolation and lack of social support (more common in lower-income
families). Such isolation may have multiple causes—mistrust of other people, a lack
of the social skills needed to maintain positive relationships, frequent moves from
place to place because of economic factors, or living in a community characterized
by violence and transience. The importance of social support is highlighted by the
fact that impoverished parents are less likely to maltreat their children if they live
in a neighborhood in which there is a prevailing sense of community, with neigh-
bors who care about and help one another (Belsky, 1993; Coulton et al., 1995;
Garbarino & Kostelny, 1992).
improved academic achievement, better re-
lationships with classmates, and reduced
activity levels (Barbaresi et al., 2007a,
2007b).
It is important to realize that the benefits
of Ritalin continue only as long as children
take the medication. Longer-lasting gains re-
quire not only medication but also behav-
ioral treatments. A large-scale clinical trial
found that high-quality medication man-
agement (with careful dosing and extensive
follow-up) paired with intensive behavioral
treatments (in this case, focused on behav-
ioral management in the context of sports
and social skills) led to more positive out-
comes than did either medication or behav-
ioral intervention alone (P. S. Jensen et al.,
2001). Parents’ disciplinary practices also
had an impact on the efficacy of these treat-
ments in this study. In particular, ADHD
treatment had the greatest impact on chil-
dren’s behavior in school when parents were
able to improve their previously negative or
ineffective parenting behavior. These find-
ings highlight the importance of considering
the impact of multiple systems on develop-
mental outcomes.
The availability of medications helpful to
those with ADHD is, of course, the result
of a perception on the part of drug compa-
nies that they can produce, sell, and make
a profit from a drug targeted for this prob-
lem. It also depends on the medication’s
receiving a favorable evaluation from the
FDA, based on research to determine the
drug’s efficacy and potential side effects.
Thus, the fate of a child in need of medi-
cation could be quite different, depending
on factors far outside the influence of his
or her family.
But would any intervention be necessary
in the first place if it were not the case that
every school-aged child is expected to spend
a substantial amount of time on most days
sitting quietly at a desk concentrating on
tasks that he or she may have little interest
in? Pointing to the highest level of the bio-
ecological model—the chronosystem—many
experts have suggested that ADHD may have
emerged as a serious problem only in recent
times—specifically, only since the advent of
compulsory schooling. Before then, an indi-
vidual who had attentional difficulties that
would have posed problems in a classroom
might very well have been able to func-
tion successfully in an environment where
such difficulties were inconsequential, even
unnoticed.
the short attention span of children with aDhD often leads them to distract not only themselves
but also other children in their classroom.
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consequences of maltreatment The consequences of child maltreatment are
manifested primarily in the microsystem (although they can extend to, and be
moderated by, factors in the mesosystem and exosystem such as child-protection
policies and agencies). In comparison with other children, maltreated children
have less secure relationships with their parents, show less empathy for other
people, and have lower self-esteem (Cicchetti & Toth, 1998; Main & George,
1985; M. Smith & Walden, 1999). In elementary school, maltreated children
are more aggressive and have more conflict with their peers (Bolger & Patterson,
2001; L. A. McCloskey & Stuewig, 2001). Later on, they have difficulty main-
taining friendships (Parker & Herrera, 1996; Rogosch, Cicchetti, & Aber, 1995;
Salzinger et al., 2001). At school, maltreated children are often anxious and in-
attentive and overly dependent on their teachers for approval and support. They
are more than twice as likely as other children to fail a grade (Eckenrode, Laird,
& Doris, 1993; Erickson et al., 1989).
We can further examine the effects of maltreatment at an even more micro
level. In our earlier discussion of the hostile attributional bias, we noted that chil-
dren who are the victims of physical abuse show a heightened response to anger
cues. This heightening is observed in behavioral responses, in brain responses
such as event-related potentials, or ERPs (e.g., Pollak et al., 1997), and in physi-
ological responses, including heart rate and skin conductance (Pollak et al., 2005).
Although such responses might be maladaptive in many social situations, leading
children to misinterpret or overreact to emotional cues, an ecological perspective
suggests that overattention to negative emotions might be highly adaptive for
children growing up in a home marked by threat and danger. By considering chil-
dren’s responses to their environments as adaptive in some contexts, but maladap-
tive in others, an ecological perspective may help explain why maltreatment has
the particular constellation of effects that it does, as well as which interventions
might be most effective (e.g., Frankenhuis & de Weerth, 2013). Of course, the
ideal situation would be to prevent child maltreatment altogether. (For a promis-
ing approach to preventing child abuse, see Box 9.3).
Children and the Media: The Good, the Bad, and the Awful
Another good illustration of the multiple levels in which children’s development
is embedded is the impact of various media—television programs, movies, video
games, and popular music. In terms of the bioecological model, media are situ-
ated in the exosystem, but they are subject to influences from the chronosystem, as
indicated earlier; from the macrosystem (including cultural values and government
policies); from other elements in the exosystem (such as economic pressures); and
from the microsystem (such as parental monitoring). All these factors are at play
every time children tune in or boot up.
Early on, when children’s in-home screen viewing was mostly limited to TV,
some educationally oriented television programming for young children was shown
to have beneficial effects (Huston & Wright, 1998). Most notably, watching Ses-
ame Street was associated with increases in young children’s vocabulary and helped
prepare them for school entry, with some positive effects persisting even through
high school (D. R. Anderson et al., 2001; Rice et al., 1990). However, as you read
in Chapter 6 (Box 6.3: iBabies: Technology and Language Learning), some “edu-
cational” DVDs actually have negative effects on language development.
As screens become ever more pervasive, moving from living rooms to bedrooms
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children now spend more time involved in using screen media than in any other activ-
ity besides sleeping. This fact was documented by a national survey conducted by the
Kaiser Family Foundation (Rideout, Foehr, & Roberts, 2010). Media usage is increas-
ing at an incredible rate; 8- to 18-year-olds upped their average screen time by more
than an hour just in the past 5 years, from an average of 6 hours 21 minutes in 2005
to 7 hours 38 minutes in 2010. Use of every type of electronic media has increased
during that time, fueled by social networking (see Box 13.2, pages 529–530), the
availability of television programming streamed on demand (rather than presented
at a fixed time, as in the past), and an explosion in the use of portable electronics. In
2012, a Pew survey revealed that 37% of American teens have smartphones, and 23%
have a tablet computer (Madden et al., 2013). Three out of every four teens use their
mobile devices to access the Internet. Even very young children are active participants
BOX 9.3: applications
PREVENTING CHILD ABUSE
Given the multiple factors that contribute
to child maltreatment, preventing or ame-
liorating the problem of abuse is extremely
difficult. However, one very promising
intervention program was developed from
research financed by federal funding agen-
cies at the macrosystem level and is carried
out at the microsystem level.
The program, reflecting a social cognition
perspective, was designed and implemented
by Daphne Bugental and her colleagues,
who found that many abusive parents have
inappropriate models of their relationship
with their children. They tend to see them-
selves and their children as locked in a
power struggle—a conflict in which they view
themselves as the victims (Bugental, Blue,
& Cruzcosa, 1989; Bugental & Happaney,
2004). Thus, they might interpret their
baby’s prolonged crying as evidence that
the baby is mad at them, and they might
think that a child who continues to beg for a
withheld toy or treat is intentionally trying to
subvert their authority.
The goal of this program was to help
parents at risk for abusing their children
achieve more realistic interpretations of
their difficulties in caring for their children
(Bugental et al., 2002). As we discussed
in Chapter 2, some children are particu-
larly at risk for abuse, including those born
preterm or with other medical complica-
tions that make parenting especially chal-
lenging. The intervention for families with
such children involved frequent home
visits in which parents were asked to
give examples of recent problems they
had had with their children and to in-
dicate what they thought had been
the cause of the problem. They were
then led to identify a cause that did
not focus blame on the children (i.e.,
something other than deliberate mis-
behavior by their children), as well as
to come up with potential strategies
for solving the problem.
A particularly important factor in
assessing this program is that at-risk
families were randomly assigned to
the intervention condition or to two
comparison conditions. Thus, any
difference in outcomes could not be
due to initial differences among the
groups.
The program was remarkably suc-
cessful: the prevalence of physi-
cal abuse in the intervention group
was only 4%, compared with around
25% in the two comparison groups.
This intervention program, targeted at
the microsystem level, suggests that
home-visiting programs that focus on altering
parents’ cognitive interpretations have a high
potential for preventing physical abuse. And,
consistent with the parent-investment theory
discussed earlier in this chapter in the con-
text of evolutionary psychology, the program
led parents to begin to invest more caregiving
in their at-risk (preterm) infants ( Bugental,
Beaulieu, & Silbert-Geiger, 2010). As par-
ents developed a greater understanding
of the needs—and the potential—of their
infants, they subsequently increased their
investment in their offspring, who later
showed substantial health benefits.
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in this media immersion: children 6 years and younger devote more time to
entertainment media than to reading, being read to, and playing outside combined
(Rideout et al., 2003).
concerns about children’s exposure to Media The nature and amount of chil-
dren’s media exposure have aroused a variety of concerns, ranging from the pos-
sible effects of media violence and pornography to those of isolation and inactivity.
MEDIA VIOLENCE Foremost among the concerns that have been raised is fear that
a steady diet of watching violent television shows, playing violent video games,
and listening to music with violent lyrics will cause children to behave violently.
The concern originally arose from the fact that television was awash in violence, as
indexed by a comprehensive study reporting that 61% of programs on television
between 1994 and 1997 contained episodes of violence (B. J. Wilson et al., 1997).
The prevalence of TV violence has since intensified, with the six major networks av-
eraging 4.4 violent incidents per hour during prime-time viewing in the 2005–2006
season (Parents Television Council, 2007). Furthermore, aggression in television
programs and movies tends to be glamorized and trivialized—particularly the vio-
lence perpetrated by heroes, who are rarely punished or condemned for their actions.
Extensive reviews of the vast amount of research on this issue have led research-
ers to conclude that the scientific debate about whether media violence increases
aggression and violence is over. The evidence is clear that media violence has nega-
tive effects on children. In 2009, a policy statement by the American Academy of
Pediatrics Council on Communications Media began by stating that “exposure to
violence in media, including television, movies, music, and video games, represents
a significant risk to the health of children and adolescents.”
Exposure to media violence has an impact in four different ways (C. A. Anderson
et al., 2003). First, seeing actors engage in aggression teaches aggressive behaviors
and inspires imitation of them, as you saw earlier in this chapter in the discussion of
Bandura’s studies with Bobo. Second, viewing aggression activates the viewer’s own
aggressive thoughts, feelings, and tendencies. This heightened aggressive mindset
makes it more likely that the individual will interpret new interactions and events as
involving aggression and will respond aggressively. Furthermore, when aggression-
related thoughts are frequently activated, they may become part of the individual’s
With the advent of handheld devices and
social networking, electronic media have
become central to the social lives of many
children and teens.
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researchers have concluded that viewing
media violence increases the incidence of
aggression and violent behavior.
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normal internal state. Third, media violence is exciting and arousing for most youth,
and their heightened physiological arousal makes them more likely to react violently
to provocations right after watching violent films. Finally, frequent long-term expo-
sure to media violence gradually leads to emotional desensitization—a reduction in
the level of unpleasant physiological arousal most people experience when observ-
ing violence. Because this arousal normally helps inhibit violent behavior, emotional
desensitization can render violent thoughts and behaviors more likely.
PHYSICAL INACTIVITY Another concern has to do with the fact that
a child who is glued to a screen is not outside playing or other-
wise engaging in robust physical activity. In addition, the thou-
sands of TV commercials with which children are bombarded
every year (at an advertiser cost of billions of dollars per year)
consist largely of advertisements for sugary cereals, candy, and
fast-food restaurants. The sedentary nature of screen time, com-
bined with the onslaught of commercials encouraging the con-
sumption of sweet, fatty foods, have been linked to the recent
increase in childhood obesity discussed in Chapter 3. Indeed,
when a child has a TV in the bedroom—as do more than 70%
of 8- to 18-year-olds (Rideout, Foehr, & Roberts, 2010)—the
child’s risk of obesity increases by 31% (Dennison et al., 2002).
EFFECTS ON ACADEMIC ACHIEVEMENT According to a study by the
Kaiser Family Foundation, there is a strong relationship be-
tween media use and school grades (Rideout et al., 2010). For example, children
who are heavy users of screen media (more than 16 hours per day) are far more
likely to report fair/poor grades (Cs or below) than are those who are moderate
users (3 to 16 hours per day) or light users (less than 3 hours per day). Of course,
there are many other confounding factors that might underlie a link between media
usage and grades, such as generally poor parental supervision, or a family culture
(parents included) that deemphasizes reading and other academic pursuits in favor
of screen time.
However, one cleverly designed study was able to draw causal conclusions about
the relation between video games and school achievement (Weis & Cerankosky,
2010). Boys in the 1st through 3rd grades who did not already own a video game
console were randomly assigned to an experimental group, whose members were
given a console at the beginning of the study, or to a comparison group, whose
members were, in the name of fairness, given a console after the study was com-
pleted. The boys who received the game console at the beginning of the study sub-
sequently spent less time on after-school academic pursuits than the boys in the
comparison group, and 4 months into the study, performed more poorly on mea-
sures of literacy and had a higher rate of teacher-reported academic problems than
did the comparison group. Boys who spent the most time with the games showed
the poorest academic outcomes.
SOCIAL INEQUITIES Another area of concern centers on the possibility that socio-
economic inequalities will be exacerbated by the “digital divide”—that is, unequal
access to and use of computers as a function of SES. Most children have some
degree of access to computers at school, but there are great differences between low-
SES and high-SES families in terms of the likelihood that computers are available
in their homes. Furthermore, higher-SES families are more likely to have newer,
more powerful computers and to have more than one of them. Thus, children from
the common practice of spending a great
deal of time watching tV while consuming
high-fat snacks and meals increases the
likelihood of childhood obesity.
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higher-SES families are far more likely to be able to use computers to do home-
work and to use the Internet than are children from poorer families. The disparity
in access to computers is less extreme at school, where computers are used exten-
sively in classrooms even in low-SES neighborhoods.
PORNOGRAPHY A serious concern for many parents is children’s exposure to pornog-
raphy on television and the Internet, whether inadvertent or intentional. Online
pornography is particularly problematic because of its ready availability. On aver-
age, American children first encounter pornography on the Web at the age of 11
(Ropelato, 2009). Research suggests that exposure to pornography can make chil-
dren and teens more tolerant of aggression toward women, as well as more accept-
ing of premarital and extramarital sex (Greenfield, 2004).
Of special concern is pornography featuring children. Child pornography is a
multibillion-dollar industry and among the fastest-growing criminal segments on
the Web (Federal Bureau of Investigation, n.d.). Today, pedophiles commonly use
the Web, including chat rooms, to share illegal photographs of children and to lure
children into sexual relationships.
The most effective weapons against the various negative effects of media on chil-
dren operate at the microsystem level, with parents exercising control over their chil-
dren’s access to undesirable media, and at the macrosystem level, with legal controls
and government programs designed to minimize the negative features of the media
with which children interact. Effective control is complicated, however, by free speech
concerns and, in the case of Internet pornography, the global nature of the problem.
SES and Development
As we have frequently noted, the SES of their families has profound effects on
children’s development. These effects originate at every level of the bioecologi-
cal model. In the microsystem, children are affected by the nature of their family’s
housing and their neighborhood, and in the mesosystem, by the condition of their
school and the quality of their teachers. Exosystem influences include the nature of
the parents’ employment or lack of employment. Macrosystem factors include the
government policies that affect employment opportunities and establish programs
like Project Head Start geared to low-income families.
Chronosystem factors also come into play with respect to changes over time in
the kind and number of jobs that are available. For example, in the United States,
the number of well-paying manufacturing jobs has been shrinking for many years,
ravaging whole communities with skyrocketing unemployment. The shrinking tax
base in those communities, and in others affected by the economic downturn of the
past several years, has resulted in fewer resources to support schools, health care,
and other community resources important for developing children.
the pervasive effects of poverty In many of our discussions throughout this
book, we focus on a number of factors that affect the development of children liv-
ing in poverty. However, the factors we discuss are only the tip of the iceberg. Table
9.1 lists a wide variety of ways that the environment of poor children in the United
States differs from that of more affluent children (summarized from G. W. Evans,
2004). Many of the items in the table will be familiar to you, but you may never
have considered some of the others. As you look over the table, think about how
these various aspects of impoverished environments interact and what their cumu-
lative impact might be. Also, consider how the many detrimental factors listed in
the table relate to the different levels of the bioecological model, from government

E C O L O G I C A L T H E O R I E S O f D E v E L O P M E N T n 377
priorities and policies to the physical health of the individual child growing
up in poverty.
As you look over the table, you should also keep in mind two points
from our discussion of the multiple-risk model in Chapter 2. First, it is the
accumulated exposure to multiple environmental risk factors that is crucial
(G. W. Evans, 2004). A child whose parents are neglectful might cope rea-
sonably well, but doing so would be more difficult if the child also goes to
a poor-quality school in a dangerous neighborhood. Second, as discussed
in Chapters 10 and 11, individual children differ with respect to how sus-
ceptible they are to environmental influences, both positive and negative
(Belsky, Bakermans-Kranenburg, & van IJzendoorn, 2002).
Because many specific effects of poverty on development are discussed
throughout the book, we will not feature them here but, instead, will exam-
ine a developmental effect of SES that often goes unnoticed: the costs of
affluence.
the costs of affluence Contrary to popular assumption, growing up
in highly affluent families can have negative effects on development. The
stereotype of the “poor little rich kid” seems to have some basis in fact. For
example, compared with inner-city adolescents, affluent youth report higher
levels of anxiety, greater depression, and more use of illicit substances (ciga-
rettes, alcohol, marijuana, and other drugs) (Luthar, 2003). Although ado-
lescents’ use of illicit substances is linked with depression and anxiety, it is
TABLE 9.1
the environment of childhood poverty
Some ways that the physical and social environments of children growing up in poverty differ from the environments of more well-off children:
PHYSICAL ENVIRONMENT
Home
Inadequate housing
Structural deficiencies
Inadequate heat
Unsafe drinking water
Poor air quality in house (including parental smoking)
Rodent infestation
Few safety features (e.g., smoke alarms)
Crowding (number of people in home)
Small yards (if any)
Neighborhood
Exposure to toxins
•   Air pollution (e.g., near highways, factories)
•   Water, soil pollution (factories, toxic waste dumps)
•   Exposure to contaminants (lead, pesticides)
Few parks or open spaces
Few places for informal gatherings
Inadequate municipal services (garbage, police, fire)
Few stores, services, including supermarkets
Less bus, taxi service
More bars, taverns
More physical hazards (traffic volume, street
crossings, playground safety)
SOCIAL ENVIRONMENT
Home
Low parental education
Low parental income
Employment instability
Frequent change of residence
Social isolation (small social networks)
Less social support
Lower marital quality (conflict)
More domestic violence (spousal, child abuse)
Higher divorce rate
More single-parent households
Harsher, punitive parenting
Low monitoring of children
Less emotional support
More corporal punishment
Less speech from parents
Less frequent literacy activities
Fewer computers/older computers
Less access to Internet
More TV watching
School
Poor quality day care
Aggressive, violent peers
Unstable peer relations
Poorer quality teachers
High teacher turnover
High student absenteeism
Less parent involvement in school
Less sense of belonging to school
Inadequate buildings (plumbing, heating,
lighting, etc.)
Overcrowding
Neighborhood
High crime rates
High level of violence
Widespread unemployment
Fewer positive adult role models
Few social resources
Source: G. W. Evans, 2004
Would you say that the children who attend
this school are from poor or from well-to-do
families?
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also associated with popularity, suggesting that peer influences may actively pro-
mote this behavior.
In attempting to account for these findings, Luthar and Becker (2002) note that
affluent parents tend to pressure their children to excel both academically and in
extracurricular activities. At the same time, these parents often provide their chil-
dren with little support. For example, because of the career demands of the parents
and their children’s many after-school activities, family time is diminished in many
high-income families (Luthar & Latendresse, 2005; Rosenfeld & Wise, 2000). In
addition, when both parents have careers, many preteens from upper-income fami-
lies are home alone after school, unsupervised, for several hours a week (Capizzano,
Tout, & Adams, 2002).
A rather remarkable fact is that, in a national survey, U.S. teens whose family
income was fairly low reported higher feelings of closeness with their mothers
and fathers than did those whose family income was much higher (Federal Inter-
agency Forum on Child and Family Statistics, 1999). In addition, the level of hap-
piness reported by youth is not directly related to their family’s level of affluence
(Csikszentmihalyi & Schneider, 2000).
Current Perspectives
The three theoretical positions discussed in this section have all made valuable con-
tributions to developmental science by placing individual development in a much
broader context than is typically done in mainstream psychology. All of them chal-
lenge researchers to look beyond the lab—far beyond it.
The primary contribution of ethology and evolutionary psychology comes from
the emphasis on children’s biological nature, including genetic tendencies grounded
in evolution. Evolutionary psychology has provided fascinating insights into human
development, but it has also come in for serious criticism. One frequent complaint
is that, like psychoanalytic theories, many of the claims of evolutionary psycholo-
gists are impossible to test. Often, a behavioral pattern that is consistent with an
evolutionary account is at least equally consistent with social learning or some
other perspective. Finally, evolutionary-psychology theories tend to overlook one
of the most remarkable features of human beings, a feature strongly emphasized by
Bronfenbrenner—our capacity to transform our environments and ourselves.
teenagers growing up in affluent families
are more likely than their peers to smoke,
drink alcohol, and use marijuana.
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C H A P T E R S U M M A R Y n 379
Bronfenbrenner’s bioecological model has made an important contribution to
our thinking about development. His emphasis on the broad context of develop-
ment and the many different interactions among factors at various levels has high-
lighted how complex the development of every child is. The main criticism of this
model is its lack of emphasis on biological factors.
What is the relevance of ecological theories to Kismet’s design? Evolution is
basically irrelevant to it. Evolutionary change does not apply to individual develop-
ment, and, without the possibility for reproduction, it simply cannot occur.
With respect to the bioecological model, Kismet is developing in an extremely
limited microsystem—Cynthia Breazeal’s lab at the Massachusetts Institute
of Technology—populated with a relatively small number of people. It has no
meso system at present, although that could change in the future. This fact makes
Kismet’s experience quite different from that of most human children. Kismet
could be affected by the macrosystem at any time, if changes in research priorities
of the federal government cut off funding for the project. In terms of the chrono-
system, such a remarkable robot was unimaginable until recently, and even more
remarkable ones are currently being developed to follow in Kismet’s footsteps.
It is interesting that the most difficult parallels to draw between Kismet’s devel-
opment and that of children and theories of social development concern the larger
context of human development. Part of what is unique about the human species is
the fact that every individual is embedded in multiple layers of human interactions,
institutions, traditions, and history.
review:
The theories we have grouped under the label “ecological theories” examine development
in a much broader context than those found in other theoretical approaches. Theories of
development based on ethology and evolutionary psychology emphasize the influence of
the evolutionary history of the human species on the development of individual children.
Parental-investment theory proposes that the perpetuation of one’s genes underlies the
enormous effort that parents invest in raising their children.
Other evolutionary theories emphasize the adaptive function of prolonged immaturity in
the development of human children. Urie Bronfenbrenner’s highly influential bioecological
model conceptualizes the environment in which children develop as a set of nested systems,
or contexts. The systems range from aspects of the environment that the individual child
directly experiences on a daily basis to the broader society and historical time in which the
child lives.
chapter summary:
Four major types of social development theories present con-
trasting views of the social world of children.
Psychoanalytic Theories
n The psychoanalytic theory of Sigmund Freud has had an
enormous impact on developmental psychology and psy-
chology as a whole, primarily through Freud’s emphasis
on the importance of early experience for personality and
social development, his depiction of unconscious motivation
and processes, and his emphasis on the importance of close
relationships.
n Freud posited five biologically determined stages of psycho-
sexual development (oral, anal, phallic, latency, genital) in which
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380 n chapter 9 THEORIES Of SOCIAL DEvELOPMENT
Children face specific conflicts at each stage, and these conflicts
must be resolved for healthy development to proceed. Freud also
posited three structures of personality—id (unconscious urges),
ego (rational thought), and superego (conscience).
n Freud believed that the Oedipus complex and the Electra
complex form the basis for superego (conscience) develop-
ment, as children identify with and adopt the values of their
same-sex parent. He thought that girls develop a weaker con-
science than boys do.
n Erik Erikson extended Freud’s theory by identifying eight
stages of psychosocial development extending across the entire
life span. Each stage is characterized by a developmental crisis
that, if not successfully resolved, will continue to trouble the
individual.
Learning Theories
n John Watson believed strongly in the power of environ-
mental factors, especially reinforcement, to influence children’s
development.
n B. F. Skinner held that all behavior can be explained in terms
of operant conditioning. He discovered the importance of
intermittent reinforcement and the powerful reinforcing value
of attention.
n Albert Bandura’s social learning theory and his empirical
research established that children can learn simply by observing
other people. Bandura has increasingly stressed the importance
of cognition in social learning.
Theories of Social Cognition
n Social cognitive theories assume that children’s knowledge and
beliefs are vitally important in social development.
n Robert Selman’s theory proposes that children go through
four stages in the development of the ability to take the role or
perspective of another person. They progress from the simple
appreciation that someone can have a view different from their
own to being able to think about the view of a “generalized
other.”
n The social information-processing approach to social cog-
nition emphasizes the importance of children’s attributions
regarding their own and others’ behavior. The role of such
attribution is clearly reflected in the hostile attributional
bias, described by Dodge, which leads children to assume
hostile intent on the part of others and to respond aggres-
sively in situations in which the intention of others is
ambiguous.
n Dweck’s theory of self-attribution focuses on how children’s
achievement motivation is influenced by their attributions
about the reasons for their successes and failures. Children
with an incremental/mastery orientation enjoy working on
challenging problems and tend to be persistent in trying to
solve them, whereas children with an entity/helpless orienta-
tion prefer situations in which they expect to succeed and tend
to withdraw when they experience failure.
Ecological Theories of Development
n Ethological theories examine behavior within the evolutionary
context, trying to understand its adaptive or survival value. The
research of Konrad Lorenz on imprinting has been particularly
relevant to certain theories of social development in children.
Sex differences have been documented in children’s toy and
play preferences.
n Evolutionary psychologists apply Darwinian concepts of
natural selection to human behavior. Characteristic of their
approach are parental-investment theory and the idea that the
long period of immaturity and dependence in human infancy
enables young children to learn and practice many of the skills
needed later in life.
n Bronfenbrenner’s bioecological model conceptualizes the
environment as a set of nested contexts, with the child at the
center. These contexts range from the microsystem, which
includes the activities, roles, and relationships in which a
child directly participates on a regular basis, to the chro-
nosystem, the historical context that affects all the other
systems.
Critical Thinking Questions
1. What influences of Freud’s theory of development can you
identify in modern society?
2. The concept of self-socialization plays a prominent role
in social cognitive theories. Explain what is meant by this
term. To what extent and in what ways do the other major
theories reviewed in the chapter allow for the possibility of
self-socialization?
3. Consider your behavior when preparing for and taking tests
and when receiving feedback on your academic performance.
Do you see yourself as having primarily an incremental/
mastery orientation or an entity/helpless orientation to aca-
demic achievement?
4. Imagine yourself raising a child. Identify one or two things
from each of the four types of theories discussed in this
chapter that you think might be helpful to you as a parent.
5. Consider Box 9.2 on attention-deficit hyperactivity disorder
(pages 370–371) and analyze what is discussed there in terms
of Bronfenbrenner’s bioecological model.

C H A P T E R S U M M A R Y n 381
Key Terms
achievement motivation, p. 359
anal stage, p. 344
attention-deficit hyperactivity disorder (ADHD),
p. 370
behavior modification, p. 351
child maltreatment, p. 369
chronosystem, p. 368
ego, p. 343
Electra complex, p. 345
entity theory, p. 359
entity/helpless orientation, p. 359
erogenous zones, p. 342
ethology, p. 362
exosystem, p. 368
genital stage, p. 345
hostile attributional bias, p. 358
id, p. 343
imprinting, p. 363
incremental theory, p. 360
incremental/mastery orientation, p. 359
intermittent reinforcement, p. 351
internalization, p. 344
latency period, p. 345
macrosystem, p. 368
mesosystem, p. 368
microsystem, p. 367
Oedipus complex, p. 344
oral stage, p. 343
parental-investment theory,
p. 365
perceived self-efficacy, p. 354
phallic stage, p. 344
psychic energy, p. 342
reciprocal determinism, p. 354
role taking, p. 357
self-socialization, p. 356
superego, p. 344
systematic desensitization, p. 350
vicarious reinforcement, p. 352

382
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W I L L I A M I R E L A N D, The Chase

383
Emotional Development
n The Development of Emotions
in Childhood
Theories on the Nature and Emergence of Emotion
The Emergence of Emotion in the Early Years
and Childhood
Box 10.1: Individual Differences Gender Differences in
Adolescent Depression
Review
n Regulation of Emotion
The Development of Emotional Regulation
The Relation of Emotional Self-Regulation to Social
Competence and Adjustment
Review
n Individual Differences in Emotion and
Its Regulation
Temperament
Box 10.2: A Closer Look Measurement of Temperament
Review
n Children’s Emotional Development
in the Family
Quality of the Child’s Relationships with Parents
Parental Socialization of Children’s
Emotional Responding
Review
n Culture and Children’s Emotional
Development
Review
n Children’s Understanding of Emotion
Identifying the Emotions of Others
Understanding the Causes and Dynamics
of Emotion
Children’s Understanding of Real and
False Emotions
Review
n Chapter Summary
chapter 10:

384
I
magine the following situation: a young girl is taken to a room in her preschool
where an experimenter shows her some tasty treats, such as M&Ms, marshmal-
lows, or pretzels. Then the experimenter tells the girl that he is going to leave
the room “for a while” and that she has two choices. If she waits until he returns
to the room, she can have two of the treats. Or if she wishes, she can ring a bell
and the experimenter will return immediately—but she will get only one treat. The
child is then left alone for a considerable period, say 15 to 20 minutes, or until she
rings the bell.
Walter Mischel and his colleagues used this procedure in numerous studies
with preschoolers and young school-aged children to study their ability to delay
immediate gratification in order to obtain larger rewards. Videotapes of what the
children did during the time they were alone with the treats showed that the chil-
dren varied in their responses. Some distracted themselves by talking, singing,
trying to sleep, or making up games to play. Others kept looking at the rewards
or the bell.
Which children do you think were most successful at curbing their desire for
the treats and holding out for the larger reward? Of course, it was the children
who distracted themselves (Mischel, 1981; Rodriguez, Mischel, & Shoda, 1989).
More important, the amount of time children were able to delay
requesting the treat proved to be a remarkably good predictor of
their social and cognitive competence and their coping skills at an
older age. For example, 10 years after the experiment, the children
were rated by their parents with regard to their academic and social
competences, as well as their verbal fluency, rational thinking, at-
tentiveness, planfulness, and ability to deal with frustration. Those
who had waited the longest in Mischel’s experiment were rated
higher on these dimensions than were those who had summoned the
experimenter back after shorter periods (Mischel, Shoda, & Peake,
1988; Peake, Hebl, & Mischel, 2002). In high school, they also
obtained higher SAT scores and scored higher on a behavioral mea-
sure requiring control of one’s attention and behavioral responses
on a computer task (Eigsti et al., 2006; Shoda, Mischel, & Peake,
1990); and at about age 27, they had achieved a higher educational
level, had higher self-esteem, and were reported to be better able
to cope with stress. Men in this group also were less likely to have
used cocaine or crack in the past year (Ayduk et al., 2000; Mischel
& Ayduk, 2004; Peake & Mischel, 2000). Furthermore, in computer-task assess-
ments 40 years after the original experiment, those who had been low in delay of
gratification in Mischel’s study continued to exhibit greater difficulty in delaying
responses to rewarding stimuli than did those who had been high in delay (Casey
et al., 2011).
That the ability to delay gratification in one situation in preschool predicted
social, emotional, and academic competence so many years later illustrates the
importance of what has been labeled “emotional intelligence,” or “affective social
competence.” Emotional intelligence refers to a set of abilities that are key to
competent social functioning. These abilities include being able to motivate one-
self and persist in the face of frustration, control impulses and delay gratification,
identify and understand one’s own and others’ feelings, regulate one’s moods, regu-
late the expression of emotion in social interactions, and empathize with others’
Themes
n Nature and Nurture
n The Active Child
n Continuity/Discontinuity
n The Sociocultural Context
n Individual Differences
Many replications of Mischel’s delay-of-
gratification study have confirmed that chil-
dren can hold out longer against temptation
if they avert their attention from the desired
object. This young girl is struggling to resist
taking the marshmallow now in front of
her in order to get two later, but she seems
likely to lose the battle.
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emotional intelligence n a set of abili-
ties that contribute to competence in the
social and emotional domains

T H E D E V E L O P M E N T O f E M O T I O N s I N C H I L D H O O D n 385
emotions (Goleman, 1995; Halberstadt, Denham, & Dunsmore, 2001; Matthews,
Zeidner, & Roberts, 2002).
The importance of emotional intelligence is reflected in the fact that, more than
almost any other measure, it predicts how well people do in life, especially in their
social lives. For example, researchers checked in with 450 boys from impoverished
neighborhoods when those boys reached middle age and discovered that how well
they had done at work and in other areas of their lives had relatively little relation
to their IQs. Rather, their successfulness corresponded with their ability to man-
age their frustration, control their emotions, and get along with others (Felsman &
Vaillant, 1987). The similarity between the results of this study and the findings of
Mischel and his colleagues underscores the point that our emotions, and how we
deal with them, play a huge role in the quality of our lives and in our relationships
with others.
In this chapter, we examine the development of children’s emotions as well as the
development of their ability to regulate their emotions and the behavior associated
with them. In addition, we discuss the development of children’s understanding
of emotion, which affects how well they can control their emotions and behavior.
In the course of our discussion, we will give particular emphasis to several of our
themes. Key among them will be the theme of individual differences, as we examine
differences among children in various aspects of their emotional functioning. We
also discuss the origins of these differences, including heredity, parental socializa-
tion practices, cultural beliefs related to emotion, and how the child’s behavior in a
given context affects his or her physiological reactions. Thus, the themes of nature
and nurture and the sociocultural context will also be prominent. The theme of the
active child is also touched upon with respect to children’s attempts to regulate their
own emotions and behavior. Finally, the theme of continuity versus discontinuity is
discussed briefly in regard to the emergence of self-conscious emotions.
The Development of Emotions in Childhood
Most people take the idea of emotion for granted and just equate the term with
“feelings.” However, developmentalists have a much more complex view of emo-
tions. They see emotions in terms of several components: (1) neural responses
involved in emotion; (2) physiological factors, including heart and breath rate and
hormone levels; (3) subjective feelings; (4) the cognitions or perceptions that cause
or are associated with the aforementioned neural and physiological responses and
subjective feelings; and (5) the desire to take action, including the desire to escape,
approach, or change people or things in the environment. In addition, emotions
can involve expressive behavior and cognitive interpretations of, or reactions to, the
feeling state (Izard, 2010; Saarni et al., 2006).
A simple example illustrates these components in combination: When people
experience fear in response to a growling dog, they typically react with heightened
physiological arousal, subjective feelings of fearfulness, thoughts about the ways
in which the dog might hurt them, and the motivation to get away from the dog.
They may also begin calculating their chances of eluding the dog and, finding them
slim, imagine the dog to be bigger and more vicious, and themselves more helpless,
than previously, thereby increasing their fear.
Although most psychologists share this general view of emotions, they often do
not agree on the relative importance of its key components (Lindquist et al., 2013;
Mulligan & Scherer, 2012; Tracy & Randles, 2011). For example, some theorists
emotion n emotion is characterized
by neural and physiological responses,
subjective feelings, cognitions related
to those feelings, and the desire to
take action

386 n chapTer 10 EMOTIONAL DEVELOPMENT
believe that cognition plays a much more important role in the experience of emo-
tion than do other theorists. Moreover, there is considerable debate concerning the
degree to which emotions are innate or learned and about when and in what form
different emotions emerge during infancy. Before considering the development of
specific emotions in childhood, we first need to examine some of the major views
that have been proposed regarding the nature and emergence of emotions.
Theories on the Nature and Emergence of Emotion
The debate about the nature and emergence of emotions in children has deep roots.
In The Expression of the Emotions in Man and Animals, published in 1872, Charles
Darwin argued that the facial expressions for certain basic emotional states are
innate to the species—and therefore similar across all peoples—and are found even
in very young babies. A corresponding view that has been held by some contempo-
rary investigators is differential (or discrete) emotions theory, which has argued
that each emotion is innately packaged with a specific set of physiological, bodily,
and facial reactions and that distinct emotions can be differentiated very early in
life (Ekman & Cordaro, 2011; Izard, 2007, 2011; Tomkins, 1962).
Other researchers maintain that emotions are not distinct from one another
at the beginning of life and that environmental factors play an important role in
the emergence and expression of emotions. Some argue, for example, that infants
experience only excitement and distress in the first weeks of life, and that other
emotions emerge at later ages as a function of experience. According to Sroufe
(1979, 1995), there are three basic affect systems—joy/pleasure, anger/frustration,
and wariness/fear—and these systems undergo developmental change from primi-
tive to more advanced forms during the early years of life. For example, wariness/
fear is first expressed as a startle or pain reaction. At a few months of age, infants
start to show wariness of novel situations, and a few months later show clear signs
of fear in novel situations. In Sroufe’s view, such changes are largely due to infants’
expanding social experiences and their increasing ability to understand them.
The role of the environment is also emphasized by theorists who take a
functionalist approach to understanding emotional development. They propose
that the basic function of emotions is to promote action toward achieving a goal
in a given context ( J. J. Campos et al., 1994; Saarni et al., 2006). The emotion of
fear, for instance, often causes one to flee or otherwise avoid a stimulus that rep-
resents a threat. This action helps achieve the goal of self-preservation (see Table
10.1 for other examples). Functionalists have also argued that emotional reactions
are affected by social goals, the immediate context and the individuals involved in
it, as well as others’ interpretations of events and their reactions to them, both in a
given context and in the past (Boiger & Mesquita, 2012; Saarni et al., 2006). For
example, young children’s experience of emotions such as shame and guilt is related
to the values and standards communicated to them by their parents, the manner in
which the values and standards are communicated, and the quality of the children’s
relationships with their parents.
Although these perspectives differ regarding whether distinct emotions emerge
early in life, each with its own set of physiological components, they all agree that
cognition and experience shape emotional development. However, few theories
within these perspectives offer a detailed description of the emotional processing
that accounts for the great variation in emotional experience and developmental
trajectories across individuals, even among those who share somewhat similar situ-
ations or characteristics.
differential (or discrete) emotions
theory n a theory about emotions, held
by Tomkins, Izard, and others, in which
emotions are viewed as innate and dis-
crete from one another from very early in
life, and each emotion is believed to be
packaged with a specific and distinctive
set of bodily and facial reactions
functionalist approach n a theory of
emotion, proposed by Campos and others,
that argues that the basic function of
emotions is to promote action toward
achieving a goal. In this view, emo-
tions are not discrete from one another
and vary somewhat based on the social
environment.

T H E D E V E L O P M E N T O f E M O T I O N s I N C H I L D H O O D n 387
An emerging perspective that explicitly deals with how the child’s character-
istics and experiences coalesce in emotional processing is dynamic-systems theory
(see Chapter 4). From this perspective, novel forms of functioning (emotional or
otherwise) arise through the spontaneous coordination of components interacting
repeatedly. In these interactions, specific cognitions (including appraisals of events
and objects), emotional feelings, and physiological and neural events tend to link
together more closely with each repeated occasion, forming coherent “emotional
interpretations” that become increasingly coordinated each time they are co-
activated (M. D. Lewis, 2005; also see Witherington & Crichton, 2007, and Fogel
et al., 1992). A dynamic-systems approach postulates that emotional reactions de-
velop differently for each person, based on an individual’s emotion-related biol-
ogy and cognitive capacities, his or her experiences, and how these factors tend to
coalesce across time in an increasingly coherent and predictable manner. As you
will see in the next section, it is not yet clear to what degree infants’ emotions are
distinct, emerge early, and can be reliably differentiated. It also is not clear to what
degree young children’s basic emotions are innate or develop as a consequence of
experience.
The Emergence of Emotion in the Early Years
and Childhood
Parents are likely to think that they see many emotions in their infants, includ-
ing interest and joy, as well as anger, fear, and sadness—even in their 1-month-
olds. In fact, however, parents often read into their infant’s emotional reaction
whatever emotion would seem appropriate in the immediate situation. For
example, if a parent gives an infant a novel toy and the infant reacts negatively,
the parent may assume that the infant’s reaction is an expression of fear, when
it could just as well be an expression of anger or upset at being overstimulated
or at having a current activity disrupted.
To make their own interpretations of infants’ emotions more objective,
researchers have devised highly elaborate systems for identifying the emotional
meaning of infants’ facial expressions. These systems involve coding dozens
of facial cues—whether an infant’s eyebrows are raised or knitted together;
TABLE 10.1
characteristics of Some Families of emotion
Emotion type Goal connected with the emotion Meaning regarding the self Meaning regarding others Action tendency
Disgust Avoiding contamination or illness This stimulus may contaminate
me or make me ill
— Active rejection of the thing
causing disgust
Fear Maintaining one’s own physical and
psychological integrity
This stimulus is threatening
to me
— Flight or withdrawal
Anger Attaining the end state that the
individual currently is invested in
There is an obstacle to my
obtaining my goal
— Forward movement, especially to
eliminate obstacles to one’s goal
Sadness Attaining the end state that the
individual currently is invested in
My goal is unattainable — Disengagement and withdrawal
Shame Maintaining others’ respect and
affection; preserving self-esteem
I am bad (my self-esteem is
damaged)
Others notice how bad I am Withdrawal; avoiding others,
hiding oneself
Guilt Meeting one’s own internalized
values
I have done something contrary
to my values
Someone has been injured
by my actions
Movement to make reparation, to
inform others, or to punish self
Adapted from Saarni et al. (1998), p. 239
as is evident from this infant’s expression,
it often is difficult to identify what negative
emotion a young infant is feeling.
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388 n chapTer 10 EMOTIONAL DEVELOPMENT
whether the eyes are wide open, tightly closed, or narrowed; whether the lips are
pursed, softly rounded, or retracted straight back; and so on—and then analyzing
the combination in which these cues are present. Even with such detailed analysis,
however, it is often hard to determine—beyond positive or negative—exactly what
emotions infants are experiencing, and it is particularly difficult to differentiate
among the various negative emotions that young infants express.
We’ll begin our examination of the emergence of emotions with the easier
task—tracing the early development of positive emotions.
Positive Emotions
The first clear sign of happiness that infants express is a smile. During the first
month, they exhibit fleeting smiles, primarily during the REM phase of sleep; after
the first month, they sometimes smile when they are stroked gently. These early
smiles may be reflexive and seem to be evoked by some biological state rather than
by social interaction (Sroufe & Waters, 1976; Wolff, 1987).
Between the third and eighth week of life, infants begin to smile in reaction
to external stimuli, including touching, high-pitched voices, or other stimuli that
engage their attention (Sroufe, 1995). More important, by the third month of
life, and sometimes as early as 6 or 7 weeks of age, babies begin to exhibit social
smiles, that is, smiles directed toward people (B. L. White, 1985). Social smiles
frequently occur during interactions with a parent or other familiar people and tend
to elicit the adult’s delight, interest, and affection (Camras, Malatesta, & Izard, 1991;
Huebner & Izard, 1988). In turn, this response usually inspires more social smiling
from the infant. Thus, the infant’s early social smiles likely promote care from par-
ents and other adults and strengthen the infant’s relationships with other people.
The social basis of social smiles is highlighted by the fact that although young
infants sometimes smile at interesting objects, humans are much more likely to
make them smile. This difference was demonstrated in a study in which 3-month-
olds smiled and vocalized much more at people, even strangers, than at puppet-
like foam balls that resembled people, were animated, and “talked” to the infant
(Ellsworth, Muir, & Hains, 1993).
When infants are at least 2 months of age, they also show happiness in both
social and nonsocial contexts in which they can control a particular event. In one
study that demonstrated this, researchers divided infants into two groups and
attached a string to an arm of each infant. Observing the infants individually, they
arranged for infants in one group to hear music whenever they pulled the string
and for infants in the other group to hear music at random intervals. The infants
who “caused” the music to play by pulling on the string showed more interest and
smiling when the music came on than did the infants whose string-pulling had no
connection to the music’s being played (M. Lewis, Alessandri, & Sullivan, 1990).
This pleasure in controlling events is evident in infants’ delight when they can con-
sistently make a noise by shaking their rattle or banging a toy on the floor.
At about 7 months of age, infants start to smile primarily at familiar people, rather
than at people in general. (In fact, as you will see, unfamiliar people often elicit dis-
tress at this age.) These selective smiles tend to delight parents and motivate them
to continue interacting with the infant. In turn, infants of this age often respond to
parents’ playfulness and smiles with excitement and joy, which also prolongs their
positive social interactions (Weinberg & Tronick, 1994). Such exchanges of positive
affect, especially when they occur with parents but not with strangers, make parents
feel special to the infant and strengthen the bond between them.
In the first weeks of life, infants’ smiles
tend to be caused by internal factors and are
not social.
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social smiles n smiles that are directed
at people. They first emerge as early as 6
to 7 weeks of age.
Smiles that arise as a function of social inter-
actions, as contrasted with those associated
with strictly biological stimuli, typically first
appear during the infant’s 3rd month.
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T H E D E V E L O P M E N T O f E M O T I O N s I N C H I L D H O O D n 389
Children’s expression of positive emotion increases across the first year of life
(Rothbart & Bates, 2006), perhaps because they are able to understand and respond
to more interesting and positive events and stimuli. After about 3 or 4 months of
age, infants laugh as well as smile during a variety of activities. For example, they
are likely to laugh when a parent tickles them or blows on their tummy, bounces
them on a knee or swings them around in the air, or shares a favorite activity such as
bathing with them. By late in the first year of life, children’s cognitive development
allows them to take pleasure from unexpected or discrepant events such as Mom’s
making a funny noise or wearing a goofy hat (Kagan, Kearsley, & Zelazo, 1978).
During the second year of life, children start to clown around themselves and
are delighted when they can make other people laugh—as in the case of this
18-month-old who looks at his mother and, fully clothed, sits on his potty:
Child: Poo (grunts heavily). Poo! (grunts). Poo! (gets up, looks at Mother,
picks up empty potty, and waves it at Mother, laughing)
(Dunn, 1988, p. 154)
Incidents like this are common in the second year of life and demonstrate infants’
desire to share positive emotion and activities with parents.
Across the preschool years and elementary school years, children’s expression
of positive emotion in social interactions, especially intense positive emotion, has
been found to decline (Sallquist et al., 2009, 2010). This pattern might be due
to children’s learning to modulate their expression of positive emotion, especially
in contexts in which it might be inappropriate or disruptive to working on tasks
(Kochanska et al., 2007).
Negative Emotions
The first negative emotion that is discernible in newborn infants is generalized
distress, which can be evoked by a variety of experiences ranging from hunger and
pain to overstimulation. Often expressed with piercing cries and a face screwed up
in a tight grimace, this type of distress is unmistakable.
The emergence and development of other negative emotions in infancy are, as
noted earlier, more difficult to pin down. A number of studies suggest that nega-
tive emotion in young infants continues to be expressed as undifferentiated distress
(Oster, Hegley, & Nagel, 1992) and that anger and distress/pain are especially likely
to be undifferentiated in most contexts (Camras, 1992; Camras & Shutter, 2010).
Dynamic-systems theorists have argued that differentiating among infants’ expres-
sion of emotions is difficult partly because their expressions of emotion are affected
by nonemotional factors such as the position of their head, their respiration, and
where they are looking (which affects the eyebrow and areas around the eye), as
well as by their immediate experience of emotion and interpretation of the context
(Camras, 2011). It is also likely that infants’ expressions of emotion often reflect
a mix of emotions, which makes it additionally difficult to know what infants are
feeling (M. Lewis, 2011).
The interpretation of negative emotions is complicated by the fact that infants
sometimes display negative emotions that seem incongruent with the situation
they are experiencing (Bennett, Bendersky, & Lewis, 2002; Camras, 1992; Hiatt,
Campos, & Emde, 1979). In the string-pulling study cited earlier, for example, the
infants who could “control” the music by pulling the string attached to their arms
fussed and sometimes expressed anger when their pulling of the string no longer
produced music. Other times, however, these infants showed fear when pulling
Some theorists believe that young infants
can experience sadness and anger, whereas
others believe that they only experience an
undifferentiated state of distress.
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390 n chapTer 10 EMOTIONAL DEVELOPMENT
the string no longer produced music (M. Lewis et al., 1990). Incongruities such as
these highlight the difficulty of knowing for certain what emotion an infant may
be experiencing in certain situations.
In some contexts involving relatively intense emotion, however, investigators have
been able to differentiate among certain negative emotions in fairly young infants.
By 2 months of age, for example, facial expressions that appear to represent anger
and sadness have been reliably differentiated from each other and from distress/
pain in situations such as getting an injection during a medical procedure (Izard,
Hembree, & Huebner, 1987). The correspondence between the context and infants’
emotional expressions seems to become more consistent from 5 to 12 months of age. For
example, in research in which experimenters prevented infants from moving their
arms, the infants’ expressions indicative of anger increased with age, whereas their
expressions of interest and surprise decreased (Bennett, Bendersky, & Lewis, 2005).
Fear and distress Although there is little firm evidence of distinct fear reactions
in infants during the first months of life (Witherington, Campos, & Hertenstein,
2001), by 4 months of age, infants do seem wary of unfamiliar objects and events
(Sroufe, 1995). Then, at around the age of 6 or 7 months, initial signs of fear begin
to appear (Camras et al., 1991), most notably the fear of strangers in many circum-
stances. In part, this shift likely reflects infants’ recognition that unfamiliar people
do not provide the comfort and pleasure that familiar people do.
Consider the following contrast: at the age of 10 weeks, as Janine was whimper-
ing in her crib, a stranger came over and smiled and talked to her. Janine stopped
fussing and smiled at the stranger. At the age of 8 months, Janine is playing on her
mother’s knee when her mother has to put her down and leave the room to answer
the door. A moment later the visitor, a stranger, enters the room without Janine’s
mother.
When the visitor enters, Janine cries. The visitor tries to comfort Janine by picking
her up and talking softly to her, but she cries still more frantically until her mother
returns and holds her. Then Janine calms down and smiles when mother lifts her high
in the air in play.
(Bronson, 1972)
In general, the fear of strangers intensifies and lasts until
about age 2. However, it should be noted that the fear of
strangers is quite variable (Sroufe, 1995), depending on both
the infant’s temperament (i.e., how fearful the infant is in
general) and the specific context, such as whether a parent
is present and the manner in which the stranger approaches
(e.g., abruptly and excitedly or slowly and calmly).
Other fears are also evident at around the age of 7 months,
including fear of novel toys, loud noises, and sudden move-
ments by people or objects, all of which tend to increase until
about 12 to 16 months of age (see Figure 10.1; Braungart-
Rieker, Hill- Soderlund, & Karrass, 2010; Kagan et al., 1978;
Scarr & Salapatek, 1970). The emergence of such fears is
clearly adaptive. Because babies often do not have the ability
to escape from potentially dangerous situations on their own,
they must rely on their parents to protect them, and expressions
of fear and distress are powerful tools for bringing help and
support when they are needed. Individual differences in the
Young children who were not afraid of
strangers at 6 months of age often suddenly
show fear of them at 7 or 8 months of age.
C
H
R
Is
T
IN
A
K
E
N
N
E
D
Y
/
P
H
O
T
O
E
D
IT

T H E D E V E L O P M E N T O f E M O T I O N s I N C H I L D H O O D n 391
decline in these kinds of fears seem to be related to the qual-
ity of children’s relationships with their mothers and how ef-
fectively their mothers deal with their children’s expressions
of fear (K. A. Buss & Kiel, 2011; Kochanska, 2001).
An especially salient and important type of fear or dis-
tress that emerges at about 8 months of age is separation
anxiety—distress due to separation from the parent who
is the child’s primary caregiver. When infants experience
separation anxiety, they typically whine, cry, or otherwise
express fear and upset. However, the degree to which chil-
dren exhibit such distress varies with the context. For exam-
ple, infants show much less distress when they crawl or walk
away from a parent than when the parent does the departing
(Rheingold & Eckerman, 1970). Separation anxiety tends to
increase from 8 to 13 or 15 months of age, and then begins
to decline (Kagan, 1976). This pattern of separation anxiety
occurs across many cultures, displayed by infants reared in
environments as disparate as the U.S. middle class, Israeli
kibbutzim (communal farming communities), and !Kung
San hunting-and-gathering groups in the Kalahari Desert
in Africa (Kagan, 1976). (Figure 10.2 shows this pattern in
Chinese and European American children.)
anger and sadness It is likely that anger is distinct from other negative emotions
by 4 to 8 months of age (Camras et al., 1991; M. W. Sullivan & Lewis, 2003). By
their 1st birthday, infants clearly and frequently express anger, often toward other
people (Radke-Yarrow & Kochanska, 1990), and their expression of anger typically
increases until 16 months of age, although there is considerable variation in this
13–1811–139–117–9
Age (in months)
<7 18–24 100 90 80 70 60 50 40 30 20 10 0 C h il d re n s h ow in g an y fe ar ( % ) DogVisual cliff Jack-in-the-box Noise 13–1811–139–117–9 Age (in months) <7 18–24 100 90 80 70 60 50 40 30 20 10 0 C h il d re n s h ow in g an y fe ar ( % ) (b)(a) FIGURE 10.1 percentages of young children showing fear of (a) the visual cliff and (b) dogs, noises, and a jack-in-the-box children 1½ to 2 years of age show the most fear of the visual cliff (see Box 5.5, page 196). children show the most fear of the jack-in-the-box and loud noises at about 1 year of age and the most fear of dogs at 1 to 1½ years of age. (adapted from Scarr & Salapatek, 1970) 5 Age (in months) 73 9 11 2913 20 0 20 40 60 80 100 S ep ar at io n : p er ce n t fr et ti n g/ cr yi n g Chinese European American FIGURE 10.2 percentages of chinese and european american chil- dren at different ages displaying fretting or crying at the departure of mother children exhibit the most evidence of separation anxiety at about 13 months of age, and chinese children have been found to display some- what more anxiety and distress than do european american children. (adapted from Kagan, Kearsley, & Zelazo, 1978) separation anxiety n feelings of dis- tress that children, especially infants and toddlers, experience when they are sepa- rated, or expect to be separated, from individuals to whom they are emotionally attached 392 n chapTer 10 EMOTIONAL DEVELOPMENT pattern across infants (Braungart-Rieker et al., 2010). Over the course of their second year, as children become better able to control their envi- ronments, they are increasingly likely to be upset when control is taken away from them or when they are otherwise frustrated (see Figure 10.3) (Goodenough, 1931). Infants often exhibit sadness in the same types of situations in which they show anger, such as after a painful event and when they cannot con- trol outcomes in their environment, although displays of sadness appear to be somewhat less frequent than displays of anger or distress (Izard et al., 1987, 1995; M. Lewis et al., 1990; Shiller, Izard, & Hembree, 1986). In addition, when older infants or young children are separated from their parents for extended periods and are not given sensitive care during this period, they often show intense and prolonged displays of sadness (Bowlby, 1973; J. Robertson & Robertson, 1971). Except in the case of children who have problematic relationships, the expression of negative emotion, and perhaps the experiencing of it as well, generally decline after the second year of life (Kochanska, 2001). Toddlers are quicker to respond with physical expressions of anger at 18 to 24 months of age than they are at 36 months or older (P. M. Cole et al., 2011); and from age 3 to 6 years, children show less negative emotion on structured labo- ratory tasks designed to elicit it (Durbin, 2010). The general decline in negative emotionality is likely due to children’s increasing ability to express themselves with language (Kopp, 1992), as well as to the increasing ability for the average child to regulate the expression of their negative feelings. The Self-Conscious Emotions: Embarrassment, Pride, Guilt, and Shame During the second year of life, children begin to show a range of new emo- tions: embarrassment, pride, guilt, and shame (Stipek, Gralinski, & Kopp, 1990; R. A. Thompson, 2006; Zahn-Waxler & Robinson, 1995). These emotions often are called self-conscious emotions because they relate to our sense of self and our consciousness of others’ reactions to us. Some investigators such as Michael Lewis believe that these emotions emerge in the second year because that is when children gain the understanding that they themselves are entities distinct from other people and begin to develop a sense of self (M. Lewis, 1998). Such a view implies an abrupt, qualitative change in children’s abilities to experience these emotions and suggests discontinuity in emotional development due to the emer- gence of an underlying cognitive awareness (M. Lewis, 1998; Mascolo, Fischer, & Li, 2003). The emergence of self-conscious emotions is also fostered by chil- dren’s growing sense of what adults and society expect of them and their ac- ceptance of these external standards (Lagattuta & Thompson, 2007; M. Lewis, Alessandri, & Sullivan, 1992; Mascolo et al., 2003). At about 15 to 24 months of age, some children start to show embarrassment when they are made the center of attention. Asked to show off an ability or a new piece of clothing, for example, they lower their eyes, hang their head, blush, or hide their face in their hands (M. Lewis, 1995). The first signs of pride are evident in children’s smiling glances at others when they have successfully met a challenge or achieved something new, like tak- ing their first step. By 3 years of age, children’s pride is increasingly tied to the level of their performance. Children express more pride, for example, when they Boys Girls Age (in years) 10 2 3 4 6 8 0.14 0.13 0.12 0.11 0.10 0.09 0.08 0.07 0.06 0.05 0.04 0.03 0.02 0.01 O u tb u rs ts p er h ou r aw ak e FIGURE 10.3 Frequency of angry out- bursts in the home children display the most anger at home during the second year of life. Displays of anger drop sharply there- after, especially for girls. (adapted from Goodenough, 1931) self-conscious emotions n emotions such as guilt, shame, embarrassment, and pride that relate to our sense of self and our consciousness of others’ reac- tions to us T H E D E V E L O P M E N T O f E M O T I O N s I N C H I L D H O O D n 393 succeed on difficult tasks than they do when they succeed on easy ones (M. Lewis et al., 1992). The two other self-conscious emotions, guilt and shame, are sometimes mistak- enly thought of as roughly equivalent, but they are actually quite distinct. Guilt is as- sociated with empathy for others and involves feelings of remorse and regret about one’s behavior, as well as the desire to undo the consequences of that behavior (M. L. Hoffman, 2000). In contrast, shame does not seem to be related to concern about others. When children feel shame, their focus is on themselves: they feel that they are exposed, and they often feel like hiding (N. Eisenberg, 2000; Tangney, Stuewig, & Mashek, 2007). Shame and guilt can be distinguished fairly early, as documented by a study in which researchers arranged for 2-year-olds to play with a doll belonging to an adult (the experimenter). The doll had been rigged so that one leg would fall off during play, while the adult was out of the room. When the “accident” occurred, some toddlers displayed a pat- tern of behavior that seemed to reflect shame—that is, they avoided the adult when she returned to the room and delayed telling her about the mishap. Other children showed a pattern of behavior that seemed to reflect guilt—that is, they repaired the doll quickly, told the adult about the mishap shortly after she returned to the room, and showed relatively little avoidance of her (Barrett, Zahn-Waxler, & Cole, 1993). In general, the degree of association of guilt feelings with bad or hurt- ful behavior increases in the second to third year (Aksan & Kochanska, 2005), and the individual differences in children’s guilt observed at 22 months of age remain relatively stable across the early preschool years (Kochanska, Gross et al., 2002). In everyday life as well, the same situation often elicits shame in some individuals and guilt in others. Which emotion children experience partly depends on parental practices. Studies of North American children have found that they are more likely to experience guilt than shame if, when they have done something wrong, their parents emphasize the “badness” of the behavior (“You did a bad thing”) rather than of the child (“You’re a bad boy”). In addition, children are more likely to feel guilt rather than shame if their parents help them understand the consequences their actions have for others, teach them the need to repair the harm they have done, avoid publicly humiliating them, and communicate respect and love for their children even when disciplining them (M. L. Hoffman, 2000; Tangney & Dearing, 2002). The situations likely to induce self-conscious emotions in children vary across cultures, as does the frequency with which specific self-conscious emotions are likely to be experienced (P. M. Cole, Tamang, & Shrestha, 2006). For instance, among traditional Zuni Indians, standing out from others is discouraged. As a re- sult, Zuni children who achieve an individual success, such as doing better than peers on a project, are likely to feel embarrassment or shame (Benedict, 1934). Sim- ilarly, the Japanese tend to avoid bestowing praise on the individual because they believe that it encourages a focus on the self rather than on the needs of the larger social group (M. Lewis, 1992). Correspondingly, Japanese children, in comparison with U.S. children, are less likely to report experiencing pride as a consequence of personal success (Furukawa et al., 2012). Moreover, in many Asian or Southeast Asian cultures that emphasize the wel- fare of the group rather than the individual, not living up to social or familial obligations is likely to evoke shame or guilt (Mascolo et al., 2003), and children children in the preschool years often exhibit shame or guilt when they do something wrong. D E s IG N P IC s / M Is T Y B E D W E LL / G E T T Y I M A G E s 394 n chapTer 10 EMOTIONAL DEVELOPMENT in these cultures report experiencing guilt and shame more than do children in the United States (Furukawa et al., 2012). In such cultures, parents’ efforts to elicit shame from their young children are often direct and disparaging (e.g., “You made your mother lose face,” “I’ve never seen any 3-year-old who behaves like you”) (Fung & Chen, 2001). This kind of explicit belittling appears to have a more positive effect on children in these Asian cultures than it does on children in Western cultures. Normal Emotional Development in Childhood The causes of emotions continue to change in childhood. For example, the basis of children’s self-esteem or self-evaluation changes with cognitive development and experience (see Chapter 11), and the events that make children feel happiness and pride tend to change accordingly. From early to middle childhood, for instance, acceptance by peers and achieving goals become increasingly important, and suc- cesses in these areas become key sources of happiness and pride. What makes chil- dren smile and laugh also changes with age. As their language skills develop along with their understanding of people and events, children in the preschool years begin to find verbal jokes funny (Dunn, 1988). Similar examples can be seen in regard to children’s negative emotions. For instance, as their cognitive ability to represent imaginary phenomena develops in the preschool years, children often start to fear imaginary creatures such as ghosts or monsters. Such fears are uncommon in elementary school children (Silverman, La Greca, & Wasserstein, 1995), probably because children of this age have a better understanding of reality than do younger children. Instead, school-aged children’s anxieties and fears are generally related to important, real- life issues (albeit sometimes exaggerated), such as challenges at school (tests and grades, being called on in class, and pleasing teachers), health (their parents’ and their own), and personal harm (being robbed, mugged, or shot). The causes of anger also change as children develop a better understanding of others’ inten- tions and motives. For example, in the early preschool years, a child is likely to feel anger when harmed by a peer whether or not the harm was intentional. In contrast, young school-aged children are less likely to be angered if they believe that harm done to them was unintentional or that the motive for some harmful action was benign rather than malicious (Coie & Dodge, 1998; Dodge, Murphy, & Buchsbaum, 1984). The frequency with which specific emotions are experienced also may change in childhood and adolescence. There is some evidence, for example, that over the course of the preschool and early school years, children generally become less emotionally intense and negative (Guerin & Gottfried, 1994; B. C. Murphy et al., 1999; Sallquist et al., 2009). There is also some support for the common assumption that negative emotion increases after middle childhood. Typically, early to middle adolescence is marked by an increase in the frequency or inten- sity of negative emotions and a decrease in positive emotion. For most youths, the increase is mild (Larson & Lampman-Petraitis, 1989; Larson et al., 2002; Weinstein et al., 2007), but for a minority, it is quite sharp, often in their rela- tions with their parents (Collins & Steinberg, 2006; Laursen, Coy, & Collins, 1998; see also Chapter 12). This negative shift in average emotions generally appears to end by grade 10, and older adolescents also experience less emotional lability (i.e., day-to-day change) than do young adolescents (Larson et al., 2002; Weinstein et al., 2007). T H E D E V E L O P M E N T O f E M O T I O N s I N C H I L D H O O D n 395 Of course, children’s emotional states are highly influenced by the world around them, with negative emotion being intensified by stressful conditions. As might be expected, children and adolescents directly exposed to war or terrorism tend to experience unusually high levels of fear, anxiety, and depression (N. Eisenberg & Silver, 2011; P. T. Joshi & O’Donnell, 2003; Weems et al., 2010). Exposure to lesser stressors, such as conflict between parents in the home, or a single mother’s entrance into a new romantic relationship or co- habitation arrangement, also appears to increase children’s experi- ence of negative emotion such as fear (Bachman, Coley, & Carrano, 2011; Davies, Cicchetti, & Martin, 2012; Rhoades, 2008). Depression Major bouts of depression are much more common in adolescence than in childhood, although a small percentage of preschoolers exhibit depressive symptoms that predict problems with depres- sion in the school years (Luby, 2010). Prior to adolescence, a child’s chance of experiencing a period of major depression is less than 3% (E. J. Costello, Erkanli, & Angold, 2006), but between ages 12 and 17, this figure increases to more than 4% for boys and more than 12% for girls (Center for Behavioral Health Statistics and Quality, 2012). Major, or clinical, depression is characterized by some combination of at least five of the following symptoms, occurring nearly every day for at least two weeks: depressed mood most of the time; marked diminished interest or pleasure in almost all activities; significant weight loss; insomnia or excessive sleeping; motor agita- tion; fatigue or loss of energy; feelings of worthlessness or excessive or inappropri- ate guilt; diminished ability to think or concentrate; recurrent thoughts of death (Hammen & Rudolph, 2003). Besides these specific diagnostic criteria, social with- drawal and bodily complaints are common in depressed youth, as is anxiety (C. M. Turner & Barrett, 2003). In addition to the adolescents who experience major depression, more than 10% of U.S. youths experience depressive symptoms that are not severe and persistent enough to be classified as clinical (Hammen & Rudolph, 2003). As discussed in Box 10.1, this rate is even higher for girls. Some investigators have found that adolescents from a lower socioeconomic level are especially prone to major depression (Hammen & Rudolph, 2003). In terms of nonclinical symptoms of depression, however, adolescents’ self-reports do not reflect such socioeconomic differences, although they do suggest some ethnic differences, with Hispanic children reporting more symptoms of depression than do European American or African American youth (Twenge & Nolen-Hoeksema, 2002). There are many possible causes of depression. One is heredity: major depres- sion often runs in families. Children whose mothers are depressed tend to exhibit a pattern of activation in the prefrontal cortex and amygdala that is associated with greater reactivity to the environment, negative emotionality, and withdrawal; they also may have elevated hormone-based stress reactivity (Cicchetti & Toth, 2006; Joormann et al., 2011). These biological correlates likely are partly due to a genetic vulnerability, but they also could be exacerbated by problems in parenting that often accompany maternal depression (Cicchetti & Toth, 2006), including insen- sitivity and disengagement (Belsky, Schlomer, & Ellis, 2012; S. B. Campbell et al., 2007; Garber & Cole, 2010; Lovejoy et al., 2000). It is common for children to experience a modest increase in the intensity of negative emotions as they move into adolescence. s W P R O D U C T IO N s / G E T T Y I M A G E s 396 n chapTer 10 EMOTIONAL DEVELOPMENT Other family factors likely also contribute to depression in youth. In particular, whether or not the mother is depressed, children’s symptoms of depression are fre- quently associated with low levels of family engagement, support, and acceptance and with high levels of negativity (Auerbach et al., 2011; Kiff et al., 2011; O. S. Schwartz et al., 2012). Chronic stress and conflict in the family also predict depression in youths (Brennan et al., 2002; Karevold et al., 2009; H. K. Kim, Capaldi, & Stoolmiller, 2003). One of the most striking features of adoles- cent depression is the gender-related dif- ferences in its occurrence (D. M. Costello et al., 2008; Twenge & Nolen-Hoeksema, 2002). By age 12, the rate of depression among U.S. girls is slightly higher than that for boys, and by age 17, girls are roughly three times more likely to be depressed (Center for Behavioral Health Statistics and Quality, 2012; Garber, Keiley, & Mar- tin, 2002; Hankin & Abramson, 1999). Es- pecially alarming is a tripling in the rate of major depression for U.S. girls between ages 12 and 15 (see figure; Center for Behavioral Health Statistics and Quality, 2012). Sim- ilar gender differences in the patterns of adolescent depression have been found in numerous countries (Galambos, Leadbeater, & Barker, 2004; Hankin et al., 1998; Wichstrom, 1999). Why are adolescent girls more likely than boys to experience depression? The biologi- cal changes of puberty tend to be more dif- ficult for girls and may contribute to girls’ vulnerability (Hilt & Nolen-Hoeksema, 2009). It also seems likely that a key fac- tor is the greater socioemotional stress that adolescence represents for girls (Petersen, Sarigiani, & Kennedy, 1991), at least in certain cultures. Important stressors may include concerns about one’s body and appearance (Hankin, Mermelstein, & Roesch, 2007). As discussed in Chapter 15, adolescent girls in the United States report greater dissatisfaction with their bod- ies than boys report with theirs. This dissat- isfaction, fueled by a cultural obsession with an “ideal” body type attainable only by a few, seems to contribute substantially to low self-esteem and depression in adolescent girls (Compian, Gowen, & Hayward, 2004; Hankin & Abramson, 1999; Harter, 2006; Wichstrom, 1999). Another stressor for girls can be the social consequences of early puberty, which represent a clear risk for depression (Negriff & Susman, 2011). Early maturity, for example, may lead young ado- lescent girls to become involved with older adolescent boys, who may pressure them to engage in sexual activity, drinking, or de- linquency. Many younger girls often are not cognitively and socially mature enough to cope with these pressures (Ge, Conger, & Elder, 1996; Ge et al., 2003). In contrast, for boys, early puberty has been less consis- tently related to internalizing problems such as depression. However, recent evidence suggests that boys who enter puberty early and move through it quickly are, in fact, at risk for depression (Ge et al., 2003; Mendle et al., 2010), in part because of a decline in the quality of their relationships with peers (Mendle et al., 2012). For both sexes, early puberty is especially likely to be associated with depressive symptoms if it is accom- panied by low popularity (Teunissen et al., 2011). For boys, starting puberty later than one’s peers is a predictor of depression as well (Negriff & Susman, 2011). Also appearing to contribute to the higher rates of depression for adolescent girls is the fact that they, more than their male peers, are prone to repeatedly focus on causes, consequences, and symptoms of their negative emotion (“I’m so fat” or “I’m so tired”) and on the meaning of their dis- tress (“What’s wrong with my life?”) with- out engaging in efforts to remedy their situation (Hankin, Stone, & Wright, 2010; Nolen-Hoeksema, Larson, & Grayson, 1999). Such thinking, called rumination, seems to in- crease the chances of becoming depressed, and some researchers have found this re- lation to be stronger for girls than for boys (Abela et al., 2012; Nolen-Hoeksema, 2012; Nolen-Hoeksema et al., 2007). Moreover, co- rumination—that is, extensively discuss- ing and self-disclosing emotional problems with another person (usually a peer)—is more common for girls and seems to further account for the gender difference in depres- sion (A. J. Rose, 2002). However, co-rumi- nation predicts greater severity of depression and anxiety in boys as well as girls (Hankin et al., 2010; Schwartz-Mette & Rose, 2012; L. B. Stone et al., 2011). BOX 10.1: individual differences GENDER DIFFERENCES IN ADOLESCENT DEPRESSION 12 13 14 15 16 17 20 15 10 5 0 P er ce n t Age percentage of major depressive episode in the past year among U.S. girls aged 12 to 17, 2008 to 2010 Between 2008 and 2010, an annual average of 12% of U.S. girls aged 12 to 17 experienced at least one episode of major depression, nearly three times the rate for boys in that age group. The percentage of girls who experienced major depression tripled between the ages of 12 and 15 (from 5.1% to 15.2%), with the rate highest at age 16. (adapted from center for Behavioral Statistics and Quality, 2012) rumination n a perseverative focus on one’s own negative emotions and on their causes and consequences, without engaging in efforts to improve one’s situation co-rumination n extensively discussing and self-disclosing emotional problems with another person T H E D E V E L O P M E N T O f E M O T I O N s I N C H I L D H O O D n 397 In addition, some investigators emphasize the role that maladaptive belief sys- tems play in the onset and maintenance of depression (Beck, 1983; Hammen & Rudolph, 2003). They argue, for example, that depressed individuals tend to see themselves and others in an excessively negative way and, thus, feel incompetent, flawed, and worthless, and view the world as cruel and unfair (Bohon et al., 2008; K. B. Hoffman et al., 2000; Rudolph & Clark, 2001). They may also feel that they cannot change things for the better because they believe that negative events are beyond their control, and they often do not take credit for their accomplishments (Garber et al., 2002; Gregory et al., 2007; Seligman, 1975). Finally, as noted in Box 10.1, depressed youths also tend to ruminate about the potential causes and nega- tive consequences of their symptoms (Schniering & Rapee, 2004); this rumination can intensify their negative feelings without leading to productive problem solving and solutions (Nolen-Hoeksema, Wisco, & Lyubomirsky, 2008; Silk et al., 2003). All these ideas about the causes of depression have received some support from research (Abela et al., 2011; Hammen & Rudolph, 2003). Other investigators argue that youths get depressed because they lack the skills needed for appropriate emotion regulation and positive social interactions (e.g., P. M. Cole, Luby, & Sullivan, 2008; Kovacs et al., 2008). Consistent with this view, children and adolescents who experience depression frequently are low in regula- tion and exhibit behavioral problems such as aggression, stealing, delinquency, and substance abuse (see Chapter 14; Diamantopoulou et al., 2011; Wiesner & Kim, 2006; Yap et al., 2011). This pattern may contribute to the difficulties depressed youths often tend to have in their relationships with peers (Rudolph, Ladd, & Dinella, 2007; Teunissen et al., 2011). It has also been proposed that peer victimization and rejection contribute to depression (Hawker & Boulton, 2000; Witvliet et al., 2010), an idea that seems supported by the finding that a sense of connection with peers and school is associated with less depression (Auerbach et al., 2011; D. M. Costello et al., 2008). However, evidence from a recent study that followed children from 4th grade to 6th grade suggests that children’s depression contributes to peer victimization, which in turn predicts low acceptance by peers, and that problems with peers did not cause depression (Kochel et al., 2012). In many cases, depression is likely due to a combination of personal vulner- ability and external stressful factors (Lewinsohn, Joiner, & Rohde, 2001). In a study of youths making the transition to middle school, for instance, those who felt that they had little control over their success in school and who demonstrated little investment in school were especially likely to show an increase in depres- sive symptoms if they also experienced the transition as stressful (Rudolph et al., 2001). Other research found that girls who were low in the regulation of sadness were prone to depressive symptoms in preadolescence if their parents were not especially caring and supportive (Feng et al. 2009). In addition, the combination of family difficulties (e.g., separation from parents) in early childhood and high lev- els of interpersonal stress later on may increase youths’ vulnerability to depression (Rudolph & Flynn, 2007), perhaps because early stress can affect the child’s ability to adapt physiologically years later (Gunnar & Vazquez, 2006). The most common treatment for depression in youth is drug therapy, but recent concerns have been raised about the possibility that antidepressants may increase the risk of suicidal thinking and behavior for some adolescents (Calati et al., 2011). An alternative therapy that has been shown to reduce adolescents’ depressive symp- toms to some degree involves programs designed to promote optimistic thinking and teach positive approaches to solving personal problems (Gillham et al., 1995; Jaycox et al., 1994; S. H. Spence, Sheffield, & Donovan, 2003). In adolescence, depression is much more common among girls than among boys and, in girls, is frequently accompanied by unhappiness with one’s appearance and weight. K A LL E s IN G E R / G E T T Y I M A G E s 398 n chapTer 10 EMOTIONAL DEVELOPMENT review: Emotions are fundamental for much of human functioning and undergo change in the early months and years of life. Smiles emerge early but do not become social until the 2nd to 3rd month of life, and what makes children smile and laugh changes with age and cognitive development. Distress in newborns involves hunger and various other discomforts; by 6 to 7 months of age, it is often caused by a stranger’s approach; by approximately 8 months of age, it is likely to be triggered by a separation from parents. Separation distress develops in similar ways in various cultures. It is hard to know exactly when anger emerges because distress/pain and anger are dif- ficult to differentiate early in life. Children may experience anger by the second month of life in response to loss of control. In the first months, it is similarly difficult to differentiate fear from distress, but fear likely has emerged by 6 or 7 months of age, when some children appear to display fear of strangers. Young children also exhibit sadness, especially when they are separated from loved ones for extended periods. The self-conscious emotions—embarrassment, pride, shame, and guilt—emerge some- what later than do most emotions, probably in the second year of life. Their emergence is tied in part to the development of a rudimentary sense of self and to an appreciation of others’ reactions to the self. Situations that evoke these emotions vary across cultures. Emotions continue to change in their occurrence and causes in childhood and adoles- cence. Depression increases markedly in adolescence, especially for girls. Age-related cogni- tive, biological, and experiential factors likely account for these changes. Regulation of Emotion Throughout life, being able to regulate one’s emotions is crucial to achieving one’s goals. Emotional self-regulation is a complex process that involves initiating, inhibiting, or modulating the following aspects of emotional functioning: 1. Internal feeling states (the subjective experience of emotion) 2. Emotion-related cognitions (e.g., thoughts about one’s desires or goals; one’s interpretation of an evocative situation; self-monitoring of one’s emotional states) 3. Emotion-related physiological processes (e.g., heart rate and hormonal or other physiological reactions, including neural activation, that can change as a func- tion of regulating one’s feeling states and thoughts) 4. Emotion-related behavior (e.g., actions or facial expressions related to one’s feelings) To complicate matters, children’s emotionality is difficult to differentiate from their self-regulation ( J. J. Gross & Barrett, 2011) and appears to affect the ways in which they regulate both their emotions and behavior (Ekas et al., 2011; Raikes et al., 2007). For example, when children are fearful, they may have more difficulty managing their thoughts, feelings, and behavior than when they are calm. Moreover, emotions often may have a regulatory function in that they affect the nature of children’s thoughts and behaviors in specific situations, for instance, whether children approach or avoid novel objects or people. The emergence of emotional regulation in childhood is a long, slow process. Obviously, young infants are not very good at controlling their emotional reactions. They are easily overwhelmed by loud noises, abrupt movements, hunger, and pain and must rely on their caregivers to settle parents often help young children to regu- late themselves by physically calming them or distracting them with an object. © I M A G E s O U R C E / s U P E R s T O C K emotional self-regulation n the pro- cess of initiating, inhibiting, or modu- lating internal feeling states and related physiological processes, cognitions, and behaviors R E G U L A T I O N O f E M O T I O N n 399 them down. Older infants also have difficulty dealing with intense emotions such as fear of strangers or of being left alone, and they often run to parents for comfort. Indeed, it takes years for children to develop the abilities to reliably regulate their emotions and control the behaviors associated with them. The Development of Emotional Regulation The development of emotional regulation is characterized by three general age- related patterns of change. The first pattern involves the transition from infants’ rely- ing almost totally on other people to help them regulate their emotions to their being increasingly able to self-regulate during early childhood. The second pattern involves the increasing use of cognitive strategies and planful problem solving to control neg- ative emotions. The third pattern involves the increasing selection and use of appro- priate, effective regulating strategies (Zimmer-Gembeck & Skinner, 2012). The Shift from Caregiver Regulation to Self-Regulation When young infants are distressed, frustrated, or frightened, their parents typically try to help them regulate their emotional arousal by attempting to soothe or dis- tract them (Gianino & Tronick, 1988). For example, mothers tend to use caressing and other affectionate behavior to calm a crying 2-month-old. Over the next few months, they increasingly include vocalizations (e.g., talking, singing, “shushing”) in their calming efforts, as well as in their attempts to divert the infant’s attention. Holding or rocking upset young infants while talking soothingly to them seems to be the most reliable approach, and feeding them if they are not highly upset is also effective ( Jahromi, Putnam, & Stifter, 2004). By 6 months of age, infants show signs of rudimentary emo- tional self-regulation. In aversively arousing or uncertain situa- tions, they may reduce their distress by unselectively averting their gaze from the source of distress. Occasionally, 6-month-olds can also self-soothe—that is, engage in repetitive rubbing or stroking of their body or clothing. Sometimes they can also distract themselves by looking specifically at neutral or positive persons or objects rather than at what has upset them, a strategy that they increas- ingly use between ages 1 and 2 (Grolnick, Bridges, & Connell, 1996; Mangelsdorf, Shapiro, & Marzolf, 1995; Parritz, 1996). Such changes in young children’s behavior are probably made possible by their growing ability to control both their own attention and their movements (Ruff & Capozzoli, 2003). Over the course of the early years, children develop and improve their ability to distract themselves by playing on their own when distressed. They also become less likely to seek comfort from their parents when they are upset (Bridges & Grolnick, 1995). And because of their growing ability to use language, when they are upset by parental demands, they are more likely to discuss and negotiate the situation with the parent than to engage in an emotional outburst (Campos, Frankel, & Camras, 2004; Klimes-Dougan & Kopp, 1999; Kopp, 1992). For example, if a preschooler is unhappy when told by a parent to stop play- ing and instead clean up his or her room, the child may verbally protest and lobby for extra playtime or work out a timetable for cleaning up rather than throwing a fit. These changes in children’s self-regulation are at least partly due to the increasing maturation of the neurological systems—including the portion of the frontal lobes Young children tend to soothe themselves by rubbing their body, sucking a thumb, or clinging to well-loved objects, such as their favorite blanket, that provide a sense of security. © H E LE N L IU / A LA M Y 400 n chapTer 10 EMOTIONAL DEVELOPMENT that are central to effortfully managing attention and inhibiting thought and be- haviors (A. Berger, 2011). They are also partly due to changes in what adults expect of children. As children age, adults increasingly expect them to manage their own emotional arousal and behavior. Once children are capable of crawling, for example, they are viewed as more responsible for their behavior and for complying with pa- rental expectations ( J. J. Campos, Kermoian, & Zumbahlen, 1992). At about 9 to 12 months of age, children start to show awareness of adults’ demands and begin to regulate themselves accordingly (Kopp, 1989). Their compliance grows rapidly in the second year of life (Kaler & Kopp, 1990), making them increasingly likely to heed simple instructions, such as to not touch dangerous objects. In the second year of life, children also show increases in the ability to inhibit their motor behavior when asked to do so—such as slowing down their walking or not touching certain attractive objects (N. P. Friedman et al., 2011; Kochanska, Murray, & Harlan, 2000). Although these abilities are quite limited in the toddler years, they improve considerably by age 3 to 5 (Moilanen et al., 2010; Putnam, Gartstein, & Rothbart, 2006) and further improve in the school years and beyond (Bedard et al., 2002; B. C. Murphy et al., 1999; Sinopoli et al., 2011). Across the early years, children’s ability to regulate their attention improves (Rueda, Posner, & Rothbart, 2011). As a result, children are increasingly able to conform to adults’ expectations, such as not hurting others when angry and staying seated at school when they would much prefer to get up and talk or play with class- mates. In adolescence, the neurological changes that occur in the cortex (see page 113) further contribute to self-regulation and other cognitive functioning. They also likely contribute to the decline in risk taking and the improvement in judgment that often occur in the transition from adolescence to young adulthood (Steinberg, 2010). The Use of Cognitive Strategies to Control Negative Emotion Whereas younger children regulate their negative emotions primarily by using behavioral strategies (e.g., distracting themselves with play), older children are also able to use cognitive strategies and problem solving to adjust to emotionally dif- ficult situations (Zimmer-Gembeck & Skinner, 2011). Finding themselves caught in unpleasant or threatening circumstances, they may rethink their goals or the meaning of events so that they can adapt gracefully to the situation. This ability helps children avoid acting in ways that might be counterproductive. When older children are teased by peers, for instance, they may be able to defuse the situation by downplaying the importance of the teasing rather than reacting to it in a way that would provoke more teasing. The Selection of Appropriate Regulatory Strategies In dealing with emotion, children, over time, improve in their ability to select cog- nitive or behavioral strategies that are appropriate for the particular situation and stressor (Brenner & Salovey, 1997). One reason is that, with age, children are more aware that the appropriateness of a particular coping behavior depends on their specific needs and goals, as well as on the nature of the problem. For example, children are increasingly likely to realize that it is better to try to find alternative ways to obtain a goal rather than simply give up in frustration when their initial efforts fail (C. A. Berg, 1989). Another reason is that planning and problem-solving skills, which likely contribute to the selection and use of appropriate strategies, im- prove across childhood and across adolescence (Albert & Steinberg, 2011; Zimmer- Gembeck & Skinner, 2011). This little girl is using signs to communi- cate that she wants to take a nap. children who can indicate their wants and needs with language or signs are less likely to get frus- trated and to exhibit unregulated behavior. E X A C T O s T O C K / s U P E R s T O C K R E G U L A T I O N O f E M O T I O N n 401 Children’s improving ability to use appropriate strategies for dealing with nega- tive situations is also aided by their growing ability to distinguish between stressors that can be controlled (such as homework) and those that cannot be controlled (such as painful but necessary medical procedures). Older children, for example, are more aware than younger children that in situations they cannot control, it is easier to man- age their emotion by simply adapting to the situation rather than trying to change it (e.g., Altshuler et al., 1995; Hoffner, 1993; Rudolph, Dennig, & Weisz, 1995). Faced with having to undergo major surgery, for instance, older children may adapt by try- ing to think about the benefits of having the surgery, such as being in better health afterward, or by distracting themselves with enjoyable activities. Younger children, in contrast, are more likely to insist that they do not need the operation. The Relation of Emotional Self-Regulation to Social Competence and Adjustment As we noted earlier, the development of emotional self-regulation has impor- tant consequences for children, especially with regard to their social competence. Social competence is a set of skills that helps individuals achieve their personal goals in social interactions while maintaining positive relationships with others (Rubin, Bukowski, & Parker, 1998). A variety of studies indicate that children who have the ability to inhibit inappropriate behaviors, delay gratification, and use cog- nitive methods of controlling their emotion and behavior tend to be well-adjusted and liked by their peers and by adults (Diener & Kim, 2004; Doan, Fuller-Rowell, & Evans, 2012; Olson et al. 2011; see N. Eisenberg, Spinrad, & Eggum, 2010). Moreover, children and adolescents who are able to deal constructively with stressful situations—negotiating with others to settle conflicts, planning strategies to resolve upsetting situations, seeking social support, and so on—generally are better adjusted than are children who lack these skills, including those who avoid dealing with stressful situations altogether (K. A. Blair et al., 2004; Compas et al., 2001; Jaser et al., 2007). Well-regulated children also do better in school than their less regulated peers do, likely because they are better able to pay attention, are bet- ter behaved and better liked by teachers and peers, and, consequently, like school better (Denham et al., 2012; Duckworth, Quinn, & Sukayama, 2012; Ponitz et al., 2009; Rimm-Kaufman et al., 2009). children who exhibit positive affect and laughter tend to be well liked by peers.fR A N C Is C O V IL LA f LO R / A LA M Y social competence n the ability to achieve personal goals in social interac- tions while simultaneously maintaining positive relationships with others 402 n chapTer 10 EMOTIONAL DEVELOPMENT review: Children’s efforts to regulate their emotions and emotionally driven behaviors change with age. Whereas young infants must rely on adults to manage their emotions, older infants and young children increasingly regulate their own emotions and behavior through such methods as averting their attention, self-soothing, and distracting themselves with activi- ties. Their ability to inhibit their actions also improves with age. Improvements in children’s regulatory capacities likely are based on increases in brain maturation that allow them to better control their attention and their own bodies, as well as on changes in adults’ expec- tations of them. In contrast to young children, who often try to cope with their emotions by taking direct action, older children also are able to use cognitive modes of coping, such as focusing on positive aspects of a negative situation or trying to think about something else altogether. In addition, they are increasingly able to select and use ways of regulating themselves and cop- ing with stress that are appropriate to the requirements of specific situations. The abilities to regulate one’s emotions and related behavior, and to deal constructively with stressful situations, are associated with high social competence and low levels of prob- lem behavior. Individual Differences in Emotion and Its Regulation Although the overall development of emotions and self-regulatory capabilities is roughly similar for most children, there also are very large individual differences in children’s emotional functioning. Some infants and children are relatively mel- low: they do not become upset easily and they usually do not have difficulty calm- ing down when they are upset. Other children are quite emotional; they get upset quickly and intensely, and their negative emotion persists for a long time. More- over, children differ in their timidity, in their expression of positive emotion, and in the ways they deal with their emotions. Compare these two 3-year-old children, Maria and Bruce, as they react to Teri, an adult female stranger: When Teri walks over to Maria and starts to talk with her, Maria smiles and is eager to show Teri what she is doing. When Teri asks Maria if she would like to go down the hall to the play room (where experiments are conducted), Maria jumps up and takes Teri’s hand. In contrast, when Teri walks over to Bruce, Bruce turns away. He doesn’t talk to her and averts his eyes. When Teri asks him if he wants to play a game, Bruce moves away, looks timid, and softly says “no.” (N. Eisenberg, laboratory observations) Children also vary in the speed with which they express their emotions, as illus- trated by the differences in these two preschool boys: When someone crosses Taylor, his wrath is immediate. There is no question how he is feeling, no time to correct the situation before he erupts. Douglas, though, seems almost to consider the ongoing emotional situation. One can almost see annoyance building until he finally sputters, “Stop that!” (Denham, 1998, p. 21) The differences among children in their emotionality and regulation of emo- tion almost certainly have a basis in heredity. For example, identical twins are more similar to each other in these aspects of their emotion and regulation than are fra- ternal twins (Rasbash et al., 2011; Saudino & Wang, 2012). However, environmen- tal stressors, including factors as diverse as negative parenting and instability in an I N D I V I D U A L D I f f E R E N C E s I N E M O T I O N A N D I T s R E G U L A T I O N n 403 adopted child’s placement (E. E. Lewis et al., 2007), are related to problems chil- dren may have with self-regulation and the expression of emotion. Undoubtedly, a combination of genetic and environmental factors jointly contributes to individual differences in children’s emotions and related behaviors (C. S. Barr, 2012; Rasbash et al., 2011; Saudino & Wang, 2012). Temperament Because infants differ so much in their emotional reactivity, even from birth, it is commonly assumed that children are born with different emotional characteristics. Differences in various aspects of children’s emotional reactivity that tend to emerge early in life are labeled as dimensions of temperament. Mary Rothbart and John Bates, two leaders in the study of temperament, define temperament as constitutionally based individual differences in emotional, motor, and attentional re- activity and self-regulation. Temperamental characteristics are seen to demonstrate consistency across situations, as well as relative stability over time. (Rothbart & Bates, 1998, p. 109) Although characteristics of temperament have generally been thought to be evident fairly early in life, there is now evidence that some may not emerge until childhood or adolescence and may change considerably at different ages (Saudino & Wang, 2012; Shiner et al., 2012). For example, incentive motivation—the vigor and rate of responding to anticipated rewards—seems to become stronger in early adolescence, which may account for reduced self-regulation in regard to rewarding but risky activities (e.g., the use of drugs and alcohol), and then drops after adoles- cence (Luciana & Collins, 2012; Luciana et al., 2012). Changes in when and how much temperament is expressed at different ages likely occur because genes switch on and off throughout development, so there are changes in the degree to which behaviors are affected by genes (Saudino & Wang, 2012). The phrase “constitutionally based” in Rothbart and Bates’s defi- nition of temperament refers, of course, to genetically inherited char- acteristics. But it also refers to aspects of biological functioning, such as neural development and hormonal responding, that can be affected by the environment during the prenatal period and after birth. For example, nutritional deficiencies or exposure to cocaine during the pre- natal period (T. Dennis et al., 2006), maternal stress and anxiety dur- ing pregnancy (Huizink, 2008, 2012), and a premature birth (C. A. C. Clark et al. 2008) all appear to have the potential to affect infants’ and young children’s ability to regulate their attention and behavior. Sim- ilar negative effects can result from sustained elevations of cortisol (a stress-related hormone that activates energy reserves) because of mater- nal insensitivity or child abuse during the early years of life (Bugental, Martorell, & Barraza, 2003; Gunnar & Cheatham, 2003). Thus, the construct of temperament is highly relevant to our themes of individual differences and the role of nature and nurture in development. The pioneering work in the field of temperament research was the New York Longitudinal Study, conducted by Alexander Thomas and Stella Chess (Thomas & Chess, 1977; Thomas, Chess, & Birch, 1968). These researchers began by interviewing a sample of parents, repeatedly and in depth, about their infants’ specific behaviors. To temperament n constitutionally based individual differences in emotional, motor, and attentional reactivity and self- regulation that demonstrate consistency across situations, as well as relative sta- bility over time Who could resist this toddler? children who smile easily in new situations—who have an easy temperament—are likely to elicit more positive reactions from adults than are chil- dren who express a high level of negative emotion. T R A C Y s P IN R A D 404 n chapTer 10 EMOTIONAL DEVELOPMENT reduce the possibility of bias in the parents’ reports, the researchers asked that instead of interpretive characterizations, such as “he’s often cranky” or “she’s interested in everything,” the parents provide detailed descriptions of their infant’s specific behaviors. On the basis of those interviews, nine characteristics of children were identified, including such traits as quality of mood, adaptability, activity level, and attention span and persistence. Further analyzing the interview results in terms of these characteristics, the researchers classified the infants into three groups: easy, difficult, and slow-to-warm-up. 1. Easy babies adjusted readily to new situations, quickly established daily rou- tines such as sleeping and eating, and generally were cheerful in mood and easy to calm. 2. Difficult babies were slow to adjust to new experiences, tended to react nega- tively and intensely to novel stimuli and events, and were irregular in their daily routines and bodily functions. 3. Slow-to-warm-up babies were somewhat difficult at first but became easier over time as they had repeated contact with new objects, people, and situations. In the initial study, 40% of the infants were classified as easy, 10% as difficult, and 15% as slow-to-warm-up. The rest did not fit into one of these categories. Of particular importance, some dimensions of children’s temperament showed rela- tive stability over time, with temperament in infancy predicting how children were doing years later. For example, “difficult” infants tended to have problems with adjustment at home and at school, whereas few of the “easy” children had such problems. (We will return to the issue of stability of temperament and its social and emotional correlates shortly.) Since the groundbreaking efforts of Thomas and Chess, researchers have devoted a great deal of effort to refining both the definition of temperament and its measurement (see Box 10.2). Unlike Thomas and Chess, many contemporary researchers differentiate among types of negative emotionality and assess different types of regulatory capacities. More recent research suggests that infant tempera- ment is captured by six dimensions (Rothbart & Bates, 1998, 2006): 1. Fearful distress/inhibition—distress and withdrawal, and their duration, in new situations 2. Irritable distress—fussiness, anger, and frustration, especially if the child is not allowed to do what he or she wants to do 3. Attention span and persistence—duration of orienting toward objects or events of interest 4. Activity level—how much an infant moves (e.g., waves arms, kicks, crawls) 5. Positive affect/approach—smiling and laughing, approach to people, degree of cooperativeness and manageability 6. Rhythmicity—the regularity and predictability of the child’s bodily functions such as eating and sleeping The terms used by investigators to refer to these dimensions vary somewhat—for example, “irritable distress” may be called “frustration” or “anger”—but these dimen- sions generally include most of the aspects of temperament that have been studied extensively. In childhood, the first five of these dimensions (see Table 10.2) are particu- larly important in classifying children’s temperament and predicting their behavior I N D I V I D U A L D I f f E R E N C E s I N E M O T I O N A N D I T s R E G U L A T I O N n 405 (Rothbart & Bates, 1998). In addition, there is some evidence that a dimension referred to as agreeableness/adaptability may be another important aspect of temperament (Knafo & Israel, 2012; Rothbart & Bates, 2006). Agree- ableness involves exhibiting positive emotions and behaviors toward others (e.g., getting along with others and caring about them versus being aggressive and manipulative), as well as the tendency to affiliate with others. Adaptability involves being able to adjust to specific condi- tions, including the needs and desires of others. TABLE 10.2 examples of Items in Mary rothbart’s Temperament Scales Response scale for items: 1 Never 2 Very rarely 3 Less than half the time 4 About half the time 5 More than half the time 6 Almost always 7 Always X Does not apply Temperament dimension Sample items in infant scale Sample items in child scale Fearful distress How often during the last week did the baby: — cry or show distress at a loud sound (blender, vacuum cleaner, etc.)? — cry or show distress at a change in parents’ appearance (glasses off, shower cap on, etc.)? — Is not afraid of large dogs and/or other animals (reversed for scoring) — Is afraid of loud noises Irritability (or distress at limitations in infancy and anger/ frustration in childhood) When having to wait for food or liquids during the last week, how often did the baby: — seem not bothered? — show mild fussing? — cry loudly? — Has temper tantrums when s/he doesn’t get what s/he wants — Gets mad when even mildly criticized Attention span How often during the last week did the baby: — look at pictures in books and/or magazines for 5 minutes or longer at a time? — play with one toy or object for 10 minutes or longer? — When drawing or coloring in a book, shows strong concentration — When building or putting something together, becomes very involved in what s/he’s doing, and works for long periods Activity level During feeding (during the last week), how often did the baby: — lie or sit quietly? — squirm or kick? — wave arms? — Tends to run, rather than walk, from room to room — When outside, often sits quietly (reversed for scoring) Positive affectivity (smiling and laughter) When tossed around playfully (during the last week), how often did the baby: — smile? — laugh? — Smiles and laughs during play with parents — Usually has a serious expression, even during play (reversed for scoring) Adapted from Rothbart Infant Behavior Questionnaire and Child Behavior Questionnaire (Rothbart & Gartstein, 1998) Due partly to variations in temperament, children often show very different reactions to the same situation. AL f R E D E Is E N s TA E D T / T IM E P IX 406 n chapTer 10 EMOTIONAL DEVELOPMENT Currently, a number of different methods are used to assess temperament. In one method, similar to that used by Thomas and Chess, parents or other adults (usually teachers or observers) report on aspects of a child’s temperament, such as fearfulness, anger/ frustration, and positive affect. These reports, based on adults’ observations of the children in various contexts (see Table 10.2), tend to be fairly stable over time and predict general later development in such areas as behavioral problems, anxiety disorders, and social com- petence (A. Berger, 2011; Rothbart, 2011; Rothbart & Bates, 2006). Laboratory observations have also been used to assess aspects of temperament such as behavioral inhibition, emotionality, and regulatory capacities. In a longitudinal study conducted by Jerome Kagan and his colleagues, for example, the investigators observed children’s reactions to a variety of novel experiences in early infancy, at age 2, and at age 4½. Across all three ages, about 20% of the children were consistently quite inhibited and reactive when exposed to the unfamiliar stimuli. As infants, they cried and thrashed about when brightly colored toys were moved back and forth in front of their faces or when a cotton swab dipped in dilute alcohol was applied to their nose. At age 2, one-third of these inhibited children were highly fearful in unfamiliar laboratory situations—such as being exposed to a loud noise, the smell of alcohol, and an unfamil- iar woman dressed in a clown outfit—and nearly all showed at least some fear in these situations. Other children were less reac- tive: as infants, they rarely fussed when they en countered the novel experiences, and at age 2, two-thirds showed little or no fear in the unfamiliar situations. At the age of 4½, the children who had been reactive to unfamiliar situations were more subdued, less social, and less positive in their behavior than were the uninhibited children, who were relatively spontaneous, asked questions of the researchers when being evaluated, commented on events happening around them, and smiled and laughed more (Kagan, 1997; Kagan & Fox, 2006; Kagan, Snidman, & Arcus, 1998). Even in adolescence, individuals who were inhibited as children exhibited some evi- dence of heightened worrying and unease with strangers (Kagan, 2012). Thus, labo- ratory observations appear to be good mea- sures of behavioral inhibition. Physiological measures also have proved useful for assessing some aspects of children’s temperament. For example, researchers have found that high-reactive and low-reactive children exhibit differences in the variability of their heart rate (Kagan, 1998; Kagan & Fox, 2006). Heart-rate variability— how much an individual’s heart rate normally fluctuates—is believed to reflect, in part, the way the central nervous system responds to novel situations and the individual’s ability to regulate emotion (Porges, 2007; Porges, Doussard- Roosevelt, & Maiti, 1994). Investi- gators often measure this fluctuation of heart rate in terms of vagal tone, an index of how effectively the vagus nerve—which regulates autonomic nervous system functioning— modulates heart rate in respiratory inhala- tion and exhalation (inhalation suppresses vagal tone, increasing heart rate; exhalation restores vagal tone, decreasing heart rate). Children who have heart rates that are con- stantly high and that vary little as a function of breathing are said to have low vagal tone. These children tend to be negatively reactive and inhibited in response to novel situations. In contrast, children who have vari- able and often lower heart rates are said to have high vagal tone. After the first year of life, these children tend to exhibit posi- tive emotions and few negative reactions in novel or even stressful situations, such as when dealing with a new preschool. Vagal tone after infancy has been linked with levels of interest and attention, as well as with levels of positive expressiveness (Beauchaine, 2001; Calkins & Swingler, 2012; R. Feldman, 2009; Fox & Field, 1989; Oveis et al, 2009). A vital component of emotion regulation is the modulation of vagal tone in challeng- ing situations that require an organized response (Porges, 2007). This modulation involves autonomic physiological processes, referred to as vagal suppression, that allow the child to shift away from the physiolog- ical responses triggered by the situation and to focus on processing information rel- evant to the situation and generating cop- ing strategies. Vagal suppression also allows for higher physiological arousal that can be used to deal with the situation at hand. Vagal suppression during challenging situ- ations has been related to a variety of posi- tive outcomes over the course of childhood, including better regulation of state and more attentional control in infancy (Huffman et al., 1998); fewer behavior problems, higher status with peers, and more appropriate emo- tion regulation in the preschool years (Calkins & Dedmon, 2000; Calkins & Keane, 2004); and sustained attention in the school years (Suess, Porges, & Plude, 1994; see also R. A. Thompson, Lewis, & Calkins, 2008). In addition, children with higher vagal tone in general or greater vagal suppression during challenges appear less likely to have problem behaviors and anxiety if exposed to stress- ors such as conflict between their parents (El-Sheikh, Harger, & Whitson, 2001; El-Sheikh & Whitson, 2006), especially if they live in environments that other wise are not especially high in stress and risk (Obradovıć et al., 2010). Findings such as these support the idea that vagal tone and its suppression assess some capacity related to adaptation and emotion regulation. Another commonly used physiological measure of temperament is electroencepha- lographic recordings (see Chapter 3, page 000) of frontal-lobe activity. Activation of the left frontal lobe of the cortex as mea- sured with an electroencephalogram (EEG) has been associated with approach behav- ior, positive affect, exploration, and sociabil- ity. In contrast, activation of the right frontal lobe has been linked to withdrawal, a state of uncertainty, fear, and anxiety (Kagan & Fox, 2006). Thus, when confronted with novel stimuli, situations, or challenges, infants and children who show greater right frontal activation on the EEG are more likely to react with anxiety and avoidance (Calkins, Fox, & Marshall, 1996; Kagan & Fox, 2006), whereas individuals who show left frontal activation are more likely to exhibit a relaxed, often happy mood and an eagerness to engage new experiences or challenges (Kagan & Fox, 2006; L. K. White BOX 10.2: a closer look MEASUREMENT OF TEMPERAMENT I N D I V I D U A L D I f f E R E N C E s I N E M O T I O N A N D I T s R E G U L A T I O N n 407 et al., 2012). EEG activation patterns are associated with children’s ongoing tempera- ment, not just with their reactions in these specific situations. For example, compared with uninhibited peers, inhibited preschool- ers showed greater activation in the right frontal area even under resting conditions, and children who were inhibited as 2-year- olds exhibited greater right than left hemi- sphere activation at age 11 (Kagan et al., 2007). A third physiological measure of tempera- ment is cortisol level. In reaction to stress, the adrenal cortex secretes steroid hor- mones, including cortisol, which, as noted previously, helps to activate energy reserves (C. S. Carter, 1986). Sometimes individual differences in children’s cortisol baseline— that is, their typical cortisol level—have been related to levels of internalizing prob- lems such as inhibition, anxiety, and social withdrawal (Granger et al., 1994; Smider et al., 2002), and to regulation (Gunnar et al., 2003) and the acting out of behavioral prob- lems (Gunnar & Vazquez, 2006; Shirtcliff et al., 2005; Shoal, Giancola, & Kirillova, 2003). For example, 2-year-olds who, in a mildly threatening situation, exhibit ex- tremely fearful reactions—such as freezing up in their behavior—tend to have higher levels of cortisol in general, not just in such situations (K. A. Buss et al., 2004). In addition, cortisol reactivity—the amount of cortisol produced in a given situation—has been linked to temperament differences in emotionality, inhibition, regulation, and mal- adjustment (Ashman et al., 2002; C. Blair et al., 2008; Granger et al., 1998). For instance, in child-care settings, children high in temperamental negative emotionality and low in regulation show larger increases in cor- tisol levels than do other children (Dettling et al., 2000). Cortisol reactivity is related to internalizing problems such as anxiety pri- marily if a child displays a heightened response to a familiar stressor (Gunnar & Vazquez, 2006). When attempting to find links between children’s cortisol levels and aspects of their temperament, it is important to consider the children’s experience in a particular context. This was highlighted in a study by Gunnar (1994), which compared the cortisol lev- els of two groups of children—outgoing and active versus anxious and withdrawn—in their first year of group care. At the start of the school year, the active and outgoing children showed higher cortisol levels; later in the school year, however, the reverse was true. According to teachers’ reports at the time of the second cortisol testing, the for- mer group was higher in popularity and had fewer problems interacting socially. Pre- sumably, the less inhibited children had actively dealt with the new situation, initially exposing themselves to stress and raising their cortisol levels but subsequently adapt- ing successfully. The inhibited children, in contrast, had avoided the challenges (and stress) of the new situation and were still not well adjusted to it (Gunnar, 1994). One exception was uninhibited children who were also unregulated; they exhibited relatively high cortisol levels at preschool even later in the year, perhaps because their impulsive behavior led to peer rejec- tion (Gunnar et al., 2003). Another excep- tion tends to be for exuberant children who are less socially integrated (Tarullo et al., 2011); they tend to maintain higher lev- els of cortisol over the school year, perhaps because they are often dealing with stressful social interactions. Each type of measure of temperament has advantages and disadvantages, and there is considerable debate regarding the mer- its of the various methods (Kagan, 1998; Kagan & Fox, 2006; Rothbart & Bates, 1998, 2006). The key advantage of parents’ reports of temperament is that parents have extensive knowledge of their children’s behavior in many different situations. One important disadvantage of this method is that parents may not always be objective in their observations, as suggested by the fact that their reports sometimes do not cor- respond with what is found with laboratory measures (Seifer et al., 1994). Another dis- advantage is that many parents do not have wide knowledge of other children’s behav- ior to use as a basis for comparison when reporting on their own children (what is ir- ritability to some parents, for example, may be near-placidness to others). The key advantage of laboratory observa- tional data is that such data are less likely to be biased than is an adult’s personal view of the child. A key disadvantage is that chil- dren’s behavior usually is observed in only a limited set of circumstances. Consequently, laboratory observational measures may reflect a child’s mood or behavior at a given moment, in a particular context, rather than reflecting the child’s general temperament. Physiological measures such as an EEG and vagal tone are also relatively objective and unlikely to be biased, but there is no way to tell whether the processes reflected by physiological measures are a cause or consequence of the child’s emotion and be- havior in the specific situation. It is unclear, for example, whether left and right fron- tal lobe activity triggers, or is triggered by, a particular emotional response. Thus, no measure of temperament is foolproof, and it is prudent to assess temperament with a variety of different methods. Nathan Fox and his colleagues have found that children’s brain activity, measured by eeG, varies as a function of whether they are experi- encing positive or negative emotions. children who are experiencing positive emotions, or who have an exuberant temperament, display more left-sided eeG activation, whereas children who are experiencing negative emotions, or who have a fearful temperament, display more right-sided activation. These different patterns, found in infants as young as 9 months, appear to reflect an underlying approach-avoidance motivation system in the brain. C O U R T E s Y O f N AT H A N A . f O X , D E P T. O f H U M A N D E V E LO P M E N T A N D Q U A N T IT AT IV E M E T H O D O LO G Y, U N IV E R s IT Y O f M A R Y LA N D 408 n chapTer 10 EMOTIONAL DEVELOPMENT Stability of Temperament over Time As you have seen, temperament, by definition, involves traits that remain fairly sta- ble over time and, in some cases, seem to increase in stability with age (Roberts & DelVecchio, 2000). One example of trait stability comes from research indicating that children who exhibited inhibition or fearful distress when presented with novel stimuli as infants also were prone to exhibit elevated levels of fear in novel situations at age 2 and elevated levels of social inhibition at age 4½. Similarly, children who are more prone to negative emotion than their peers at age 3 tend to be more emotion- ally negative than their peers at ages 6 and 8 (Guerin & Gottfried, 1994; Rothbart, Derryberry, & Hershey, 2000), and, across the same age range, those prone to positive affect remain relatively positive (Durbin et al. 2007; Sallquist et al., 2009). Research further indicates that children who are high in the ability to focus attention in the preschool years are high in this ability in early adolescence (B. C. Murphy et al., 1999) and that there is also stability in attentional and behavioral regulation from childhood into adolescence (N. Eisenberg, Hofer et al., 2008) and across adolescence (Ganiban et al., 2008). As noted, some aspects of temperament tend to be more stable than others. For example, over the course of infancy, positive emotionality, fear, and distress/anger activity level may be more stable than activity level (Lemery et al., 1999). The Role of Temperament in Children’s Social Skills and Maladjustment One of the reasons for researchers’ deep interest in temperament is that it plays an important role in determining children’s social adjustment. Consider a boy who is prone to anger and has difficulty controlling this emotion. Compared with other boys, he is likely to sulk, to yell at others, and to be defiant with adults and aggressive with peers. Such behaviors often lead to long-term adjustment problems. Consequently, it is not surprising that differences in aspects of temperament such as anger/irritability, positive emotion, and the ability to inhibit behavior—aspects reflected in the difference between difficult and easy temperament—have been associated with differences in children’s social competence and maladjustment (Coplan & Bullock, 2012; Eiden et al., 2009; N. Eisenberg et al., 2010; Kagan, 2012; Kochanska et al., 2008). Such differences are highlighted by a large longitudinal study conducted in New Zealand by Caspi and colleagues. These researchers found that participants who were negative and unregulated as young children tended as adolescents or young adults to have more problems with adjustment, such as not getting along with oth- ers, than did peers with different temperaments. They were also more likely to engage in illegal behaviors and to get in trouble with the law (Caspi et al., 1995; Caspi & Silva, 1995; B. Henry et al., 1996). At age 21, they reported getting along less well with whomever they were sharing living quarters (e.g., roommates) and reported being unemployed more often. They also tended to have few people from whom they could get social support (Caspi, 2000) and were prone to negative emo- tions like anxiety (Caspi et al., 2003). At age 32, they had poorer physical health and personal resources, greater substance dependence, more criminal offenses, and more problems with gambling (Moffitt et al., 2011; Slutske et al., 2012). a fetus’s activity level in the womb appears to be related to some aspects of postnatal temperament. Infants who were more active as fetuses tend to be active, difficult, and nonadaptive in the first half-year of life. M O O D B O A R D / s U P E R s T O C K I N D I V I D U A L D I f f E R E N C E s I N E M O T I O N A N D I T s R E G U L A T I O N n 409 It is important to note, however, that aspects of temperament like negative emo- tionality may not always be associated with children’s negative outcomes such as having problem behaviors and poor social relationships. It seems that some chil- dren with certain temperamental characteristics are especially sensitive to their social environments, whether positive or negative. There is some evidence, for example, that, in highly stressful social environments (i.e., poverty, exposure to harsh parent- ing), children who are prone to negative emotions tend to do worse than children who are not, but that, in supportive social environments, they often tend to do better than their more emotionally positive peers (Belsky & Pluess, 2009). Evolutionarily oriented theorists argue that this “for better or for worse” pattern of findings, labeled differential susceptibility, occurs because aspects of temperament and behavior that are adaptive for survival vary across positive and negative social contexts (B. J. Ellis et al., 2011). For instance, in harsh environments, expressing negative emotion may help children to obtain attention and vital resources needed for survival (even though the negative emotion often results in negative social consequences over time), whereas in supportive environments, proneness to negative emotions might make children more sensitive to parents’ attempts to socialize positive behaviors, which may lead to higher social and moral competence (Kochanska, 1997a). Researchers also have found stability with regard to behavioral inhibition, the tendency to be high in fearful distress and restrained when dealing with novel or stressful situations. Children who are behaviorally inhibited are more likely than other children to have problems such as anxiety, depression, phobias, and social withdrawal at older ages (Biederman et al., 1990; Fox & Pine, 2012; Hirshfeld- Becker et al., 2007; Moffitt et al., 2007). Thus, different problems with adjustment seem to be associated with different temperaments. However, how children ultimately adjust depends not only on their tempera- ment but also on how well their temperament fits with the particular environment they are in—what is often called goodness of fit. On the basis of their data, Chess and Thomas (1990) argued, for example, that children with difficult temperaments have better adjustment if they receive parenting that is supportive and consis- tent rather than punitive, rejecting, or inconsistent. In support of their argument, research indicates that children who are impulsive or low in self-regulation seem to have more problems and are less sympathetic to others if exposed to hostile, intrusive, and/or negative parenting rather than to supportive parenting (Hastings & De, 2008; Kiff et al., 2011; Lengua et al., 2008; Valiente et al., 2004; see also Rothbart & Bates, 2006). Similarly, children prone to negative emotions such as anger are more likely to have behavioral problems such as aggression if exposed to hostile parenting or low levels of positive parenting (Calkins, 2002; Lengua, 2008; Mesman et al., 2009; Morris et al., 2002; see also Bates et al., 2012, for a review). Thus, children exposed to suboptimal parenting do worse if they have unregulated or reactive temperaments. Not only are children’s maladjustment and social competence predicted by the combination of their temperament and their parents’ child-rearing practices, but the child’s temperament and parents’ socialization efforts also seem to affect each other over time (Belsky et al., 2007; N. Eisenberg et al., 1999; K. J. Kim et al., 2001; E. H. Lee et al., 2013). For example, parents of negative, unregulated children may eventually become less patient and more punitive with their children; in turn, this intensification of disciplining may cause their children to become even more nega- tive and unregulated. Thus, temperament plays a role in the development of chil- dren’s social and psychological adjustment, but that role is complex and varies as a function of the child’s social environment and the degree to which a child repre- sents a challenge to the parent (Ganiban et al., 2011). behavioral inhibition n a temperamen- tally based style of responding character- ized by the tendency to be particularly fearful and restrained when dealing with novel or stressful situations goodness of fit n the degree to which an individual’s temperament is compat- ible with the demands and expectations of his or her social environment 410 n chapTer 10 EMOTIONAL DEVELOPMENT review: Temperament refers to individual differences in various aspects of children’s emotional reactivity, regulation, and other characteristics such as behavioral inhibition and activity level. Temperament is believed to have a constitutional (biological) basis, but it is also af- fected by experiences in the environment, including social interactions. Temperament tends to be somewhat stable over time, although the degree of its stability varies across the dimen- sions of temperament and individuals. Temperament plays an important role in adjustment and maladjustment. A difficult and unmanageable temperament in childhood tends to predict problem behaviors and low social competence in childhood and adulthood, and children who as infants are fearful and nega- tively reactive to novel objects, places, and people sometimes have later difficulties in inter- actions with others, including peers. However, children whose temperaments put them at risk for poor adjustment often do well if they receive sensitive and appropriate parenting and if there is a good fit between their temperament and their social environment. Children’s Emotional Development in the Family It is clear that the dimensions of temperament related to emotional development are linked to heredity. Twin and adoption studies show that, compared with fra- ternal twins, identical twins are more similar in the intensity of their emotional reactions, shyness, and sociability, as well as in other aspects of temperament and personality. Furthermore, biological siblings tend to be more similar to one another in some aspects of temperament than do siblings who are not biologically related. On the basis of such studies, it is estimated that genes account for a substantial portion of the variation in some aspects of temperament (Saudino & Wang, 2012). In addition, recent studies of specific genes have shown connections between an individual’s genes and aspects of temperament such as self-regulatory capaci- ties and emotionality (Depue & Fu, 2012; Goldsmith, Pollak, & Davidson, 2008; Saudino & Wang, 2012). For example, genes related to the functioning of dopamine and other neurotransmitters that affect voluntary attentional processes (executive attention) appear to be especially relevant for self-regulation (Posner, Rothbart, & Sheese, 2007). The expression of these genes appears to be affected by environ- mental factors such as quality of parenting or stress. Sometimes genetic tenden- cies toward certain temperamental traits (and related behaviors) are most likely expressed when the environment is suboptimal—for example, when parenting is unsupportive or harsh (Bakermans-Kranenburg & van IJzendoorn, 2006; Kochanska, Philibert, & Barry, 2009; Sheese et al., 2007; H. J. Smith et al., 2012), and sometimes when the environment is optimal (Krueger et al., 2008; Pluess & Belsky, 2013). Findings in behavioral genetics research also suggest that various environmen- tal factors play an important role in shaping individual differences in temperament generally (Deater-Deckard, Petrill, & Thompson, 2007; Saudino & Wang, 2012). Chief among these factors are children’s relationships with their parents and their parents’ socialization practices. Quality of the Child’s Relationships with Parents The quality of a child’s relationship with his or her parents can affect the child’s emo- tional development in several ways. As is discussed fully in Chapter 11, the parent– child relationship seems to influence children’s sense of security and how they feel about themselves and other people (R. A. Thompson, 2006). In turn, these feelings affect children’s emotionality. For instance, children who are securely attached—that is, C H I L D R E N ’ s E M O T I O N A L D E V E L O P M E N T I N T H E f A M I L Y n 411 who have high-quality, trusting relationships with their parents—tend to show more positive emotion and less social anxiety and anger than do children who are insecurely attached—that is, whose relationships with their parents are low in trust and sup- port (e.g., Bohlin, Hagekull, & Rydell, 2000; Borelli et al., 2010; Kochanska, 2001). Securely attached children also tend to be more open and honest in their expression of emotion (Becker-Stoll, Delius, & Scheitenberger, 2001; Zimmerman et al., 2001) as well as more advanced in their understanding of emotion (Steele, Steele, & Croft, 2008), perhaps because their parents are more likely to discuss feelings and other mental states with them (McElwain, Booth-LaForce, & Wu, 2011; McQuaid et al., 2007; Raikes & Thompson, 2006). This enhanced understanding of emotion is likely to help these children recognize when and how to regulate their emotion. Parental Socialization of Children’s Emotional Responding In addition to being affected by the overall parent–child relationship, children’s emotional development is influenced by parents’ socialization of their children— that is, their direct and indirect influence on their children’s standards, values, and ways of thinking and feeling. Parents socialize their children’s emotional devel- opment through (1) their expression of emotion with their children and other people, (2) their reactions to their children’s expression of emotion, and (3) the discussions they have with their children about emotion and emotional regulation. These avenues of socialization, which are often interrelated, can affect not only children’s emotional development but also their social competence ( J. K. Baker, Fenning, & Crnic, 2011). Parents’ Expression of Emotion How parents express their own emotions can have a powerful socializing effect on their children in several ways. To begin with, the emotions expressed in the home may influence children’s views about themselves and others in their social world (Dunsmore & Halberstadt, 1997). For example, children exposed to a lot of anger and hostility may come to view themselves as individuals who anger people and may eventually believe that most people are hostile. In addition, parents’ expres- sion of emotion provides children with a model of when and how to express emo- tion (Denham, Zoller, & Couchoud, 1994; Dunn & Brown, 1994). This modeling socialization n the process through which children acquire the values, stan- dards, skills, knowledge, and behaviors that are regarded as appropriate for their present and future role in their particular culture children who are exposed to relatively high levels of positive emotion in the family tend to express more positive emotion and are more socially skilled and better adjusted than children who are exposed to high levels of negative emotion.PH O T O D Is C / T H IN K s T O C K G E T T Y I M A G E s 412 n chapTer 10 EMOTIONAL DEVELOPMENT also may affect children’s understanding of what types of emotional expressions are appropriate and effective in interpersonal relations (Halberstadt et al., 1995; Morris et al., 2007). In families in which parents tend not to express emotions, chil- dren may get the message that emotions are basically bad and should be avoided or inhibited (Gottman et al., 1997). Finally, the parental emotions to which children are exposed may affect their general level of distress and arousal in social interactions, in turn affecting their ability to process important information about the interactions (e.g., others’ verbal and nonverbal cues) that would help them moderate their behav- ior (N. Eisenberg, Cumberland, & Spinrad, 1998; M. L. Hoffman, 2000). Whatever the underlying reason, it is clear that the consistent and open expres- sion of positive or negative emotion in the home is associated with specific out- comes for children. In a review of a considerable number of studies, Halberstadt and colleagues found that when positive emotion is prevalent in the home, children tend to express positive emotion themselves. They are socially skilled, well adjusted, low in aggression, able to understand others’ emotions (at least in childhood), and tend to have high self-esteem (Halberstadt, Crisp, & Eaton, 1999; see also Barry & Kochanska, 2010; Brophy-Herb et al., 2011; McCoy & Raver, 2011). In contrast, when negative emotion is prevalent in the home, especially intense and hostile emotion, children tend to exhibit low levels of social competence and to experience and express negative emotion themselves, including depression and anx- iety (Crockenberg & Langrock, 2001; N. Eisenberg et al., 2001; Raval & Martini, 2011; Stocker et al., 2007). Even when the conflict and anger in the home involve the adults rather than the children directly, there is an increased likelihood that the children will develop anger, behavior problems, and deficits in social competence and self-regulation (Grych & Fincham, 1997; Kouros, Cummings, & Davies, 2010; Rhoades, 2008; Rhoades et al., 2011). These outcomes are also more likely when children are exposed to high levels of parental depression (Blandon et al., 2008; Cicchetti & Toth, 2006; Downey & Coyne, 1990). Of course, parental expression of emotion is not always causally related to posi- tive or negative outcomes in children: children themselves undoubtedly influence the expression of emotion in the home. For example, children who have difficult temper- aments or are unmanageable are likely to evoke negative emotion from their parents (N. Eisenberg et al., 2008; K. J. Kim et al., 2001). Moreover, genetic factors may con- tribute to some of the associations between parental emotion and children’s emotions or behavior (Burt et al., 2005; Reiss, 2010; Rhoades et al., 2011). That is, because of heredity, both parent and child may be prone to anger and impulsive behavior, which affects the quality of both parenting and children’s socioemotional compe- tence. Thus, both heredity and the kinds of emotions children see and experience in the home undoubtedly play roles in children’s emotional and social development. Parents’ Reactions to Children’s Emotions Parents’ reactions to their children’s negative emotions also seem to affect children’s emotional expressivity, as well as their social competence and adjustment. Consider, for example, the different parental messages conveyed in the following two instances: Jeremy . . . watched the movie Jaws, against his mother’s better judgment. He fear- fully, animatedly asked many questions about the movie afterwards, and anxiously discussed it in great detail (e.g., “What was that red stuff?”). His mother and father answered all the questions and supported him as he resolved these things in his mind. Jeremy’s emotions were accepted, and he was able to regulate them, as well as to learn about what makes things “scary.” (Denham, 1998, p. 106) C H I L D R E N ’ s E M O T I O N A L D E V E L O P M E N T I N T H E f A M I L Y n 413 Scott’s parents, who are punitive socializers, show disregard and even contempt when his best friend moves away. These parents tease Scott for his tender feelings, so that in the end he is let down not only by the disappearance of his friend, but by their re- actions as well. . . . [H]e is very lonely and still feels very bad. (Denham, 1998, p. 120) Parents who, like Scott’s, dismiss or criticize their children’s expressions of sadness and anxiety communicate to their children that their feelings are not valid. Parents send similar messages when they react to their children’s anger with threats, belligerence, or dismissive comments. In turn, their children are likely to be less emotionally and socially competent than are children whose parents are emotionally supportive. They tend, for example, to be lower in sympathy for others, less skilled at coping with stress, and more prone to negative emotions and problem behaviors such as aggression (N. Eisenberg, Fabes, & Murphy, 1996; Engle & McElwain, 2010; Luebbe, Kiel, & Buss, 2011; Lunkenheimer, Shields, & Cortina, 2007; J. Snyder, Stoolmiller et al., 2003). In contrast, parents who are supportive when their children are upset help their children to regulate their emotional arousal and to find ways to express their emo- tions constructively. In turn, their children tend to be better adjusted and more competent both with peers and academically (Gottman, Katz, & Hooven, 1997; Klimes-Dougan et al., 2007; Raval & Martini, 2011). Parents’ supportive reactions to their young children’s emotional upsets may be especially helpful in reducing problem behaviors for those children who have difficulty regulating their physi- ological responses to challenges (see Box 10.2; Hastings & De, 2008). Parents’ Discussion of Emotion As you will shortly see, children’s emotional understanding is a key part of their emotional development and self-regulation. Family conversations about emotion are therefore an important aspect of children’s emotional socialization. Parents who discuss emotions with their children teach them about the meanings of emo- tions, the circumstances in which they should and should not be expressed, and the consequences of expressing or not expressing them (N. Eisenberg et al., 1998; LaBounty et al., 2008; R. A. Thompson, 2006). An additional help in emotional socialization is emotion coaching, in which parents not only discuss emotions with their children but also help them learn ways of coping with their emotions and expressing them appropriately (Gottman et al., 1997; Power, 2004). Children who receive these types of guidance tend to display better emotional understanding than children who do not. A longitudinal study by Judy Dunn and her colleagues found, for example, that the degree to which children are exposed to, and participate in, discussions of emo- tions with family members at ages 2 and 3 predicts their understanding of oth- ers’ emotions until at least age 6 ( J. R. Brown & Dunn, 1996; Dunn, Brown, & Beardsall, 1991; Dunn, Brown et al., 1991). In two similar studies, mothers’ refer- ences to their children’s desires at 15 months of age predicted their children’s under- standing of emotions and use of emotion language at 24 months. In fact, mothers’ verbal references to others’ thoughts and knowledge when describing a series of pictures to their children at 24 months of age predicted children’s use of emo- tion language and understanding of emotion at 33 months of age (Taumoepeau & Ruffman, 2006, 2008). Indeed, in these same two studies, as well as in another (Ensor & Hughes, 2008), mothers’ references to others’ mental states predicted children’s emotion understanding better than did mothers’ references to emotions themselves, perhaps because references to mental states help children understand the thoughts that accompany and motivate emotional states. 414 n chapTer 10 EMOTIONAL DEVELOPMENT Researchers have also found that children whose parents use emotion coach- ing are more socially competent with peers, more empathic, and less likely to exhibit problem behaviors or depression than are children who do not receive such guidance (Brophy-Herb et al., 2011; Katz, Maliken, & Stettler, 2012; Stocker et al., 2007). Of course, children’s own characteristics—such as their ability to sus- tain attention and their initial understanding of emotions—may affect the degree to which adults talk about emotion with them. For instance, in one study, parents engaged in more conversations about emotional past events with their 5- and 6-year-olds if the children were relatively well regulated and if their expression of negative emotion was consistent with what their parents expected from a child of their age (Bird, Reese, & Tripp, 2006). review: Children’s emotional development is influenced by their relationship with their parents: chil- dren who have secure relations with their parents tend to show more positive emotion and greater emotional understanding than do children who have insecure relations with their par- ents. Another influence on children’s emotional development is their parents’ socialization of emotional responding—including what emotions parents express with their children and oth- ers, and how they express them; how parents respond to their children’s negative emotions; and whether and how parents discuss emotions with their children. Culture and Children’s Emotional Development Although people in all cultures appear to experience most of the same basic emo- tions, there is considerable cultural variation in the degree to which certain emo- tions are expressed. One reason for this may be genetic, in that people in different racial or ethnic groups may tend, on average, to have somewhat different temper- aments. This possibility has been tentatively suggested by cross-cultural studies that were conducted with young infants to minimize the potential for the results to be affected by socialization. One such study found that, in general, 11-month- old European American infants react more strongly to unfamiliar stimuli than do Chinese or Chinese American babies and cry or smile more in response to evoca- tive events (e.g., scary toys or a vanishing object) (Freedman & Freedman, 1969). Another study found that, compared with Chinese infants, American infants also respond more quickly to negative emotion-inducing events such as having their arm held down so they cannot move it (Camras et al., 1998). A more obvious contributor to cross-cultural differences in infants’ emotional expression is the diversity of parenting practices. In Central Africa, for example, the infants in an Ngandu community fuss and cry more than infants in an Aka com- munity do. This may be attributable to differences in caregiving practices related to the contrasting lifestyles of these two groups. Aka infants are almost always within arm’s reach of someone who can feed or hold them when the need arises. The Ngandu leave their infants alone more often. Thus, Aka infants may cry and fuss less because they have more physical contact with caregivers and their needs are met more quickly (Hewlett et al., 1998). The influence of cultural factors on emotional expression is strikingly revealed by a comparison of East Asian and American children. In one study, Japanese and American preschoolers were asked to say what they would do in hypothetical situa- tions of conflict and distress, such as being hit or seeing a peer knock down a tower C U L T U R E A N D C H I L D R E N ’ s E M O T I O N A L D E V E L O P M E N T n 415 of blocks they had just built. American preschoolers expressed more anger and aggression in response to these vignettes than did Japanese children. This difference may have to do with the fact that American mothers appear to be more likely than Japanese mothers to encourage their children to express their emotions in situations such as these (Zahn-Waxler et al., 1996). These tendencies are in keeping with the high value European American culture places on independence, self-assertion, and expressing one’s emotions, even negative ones (Zahn-Waxler et al., 1996). In con- trast, Japanese culture emphasizes interdependence, the subordination of oneself to one’s group, and, correspondingly, the importance of maintaining harmonious interpersonal relationships. A similar contrast is found in other East Asian cultures, such as in China, where mothers often discourage their children from expressing negative emotion, especially anger (Markus & Kitayama, 1991; Matsumoto, 1996; Mesquita & Frijda, 1992). As a consequence, children in such societies learn not to communicate certain negative feelings (Raval & Martini, 2009). Cultures also differ in the degree to which they promote or discourage spe- cific emotions, and these differences are often reflected in parents’ socialization of emotion. For example, Chinese culture strongly emphasizes the need to be aware of oneself as embedded in a larger group and to maintain a positive image within that group. Thus, shame would be expected to be a powerful emotion—important for self-reflection and self-perfection (Fung, 1999; Fung & Chen, 2001) and par- ticularly useful for inducing compliance in children. In fact, Chinese (Taiwanese) parents frequently try to induce shame in their preschool children when they trans- gress, typically pointing out that the child’s behavior is judged negatively by people outside the family and that the child’s shame is shared by other family members (Fung & Chen, 2001). Because of this cultural emphasis, it is likely that children in this society experience shame more frequently than do children in many West- ern cultures. Moreover, when children in Western cultures do experience shame or sadness, their mothers seem to be most concerned with helping them feel better about themselves. In contrast, Chinese mothers more often than Western moth- ers use the situation as an opportunity to teach proper conduct and help their child understand how to conform to social expectations and norms—for example, asking “Isn’t it wrong for you to get mad at Papa?” (Cheah & Rubin, 2004; Friedlmeier, Corapci, & Cole, 2011; Q. Wang & Fivush, 2005). Another striking example of cultural influences on emotional socialization is provided by the Tamang in rural Nepal. The Tamang are Buddhists who place great value on keeping one’s sem (mind-heart) calm and clear of emotion, and they believe that people should not express much negative emotion because of its dis- ruptive effects on interpersonal relationships. Consequently, although Tamang par- ents are responsive to the distress of infants, they often ignore or scold children older than age 2 when those children express anger, and they seldom offer explana- tions or support to reduce children’s anger. Such parental reactions are not typical of all Nepali groups, however; for example, parents of Brahman Nepali children respond to children’s anger with reasoning and yielding. Of particular interest is the fact that although nonsupportive parental behavior comparable to that of the Tamang has been associated with low social competence in U.S. children, it does not seem to have a negative effect on the social competence of Tamang children. Because of the value placed on controlling the expression of emotion in Tamang culture, parental behaviors that would seem dismissive and punitive to American parents likely take on a different meaning for Tamang par- ents and children and probably have different consequences (P. M. Cole & Dennis, 1998; P. M. Cole et al., 2006). Interviews with children in remote villages in Nepal allowed pamela cole and her col- leagues to examine how Buddhist and hindu values contribute to children’s under- standing of emotion. C O U R T E s Y O f P A M E LA C O LE 416 n chapTer 10 EMOTIONAL DEVELOPMENT Parents’ ideas about the usefulness of various emotions also vary in different cul- tural and regional groups within the United States. In a study of African American mothers living in dangerous neighborhoods, mothers valued and promoted their daughters’ readiness to express anger and aggressiveness in situations related to self-protection because they wanted their daughters to act quickly and decisively to defend themselves when necessary. One way they did this was to play-act the role of an adversary, teasing, insulting, or challenging their daughters in the midst of everyday interactions. An example of this is provided by Beth’s mother, who initi- ated a teasing event by challenging Beth (27 months old) to fight: “Hahahaha, Hahaha. Hahahaha. [Provocative tone:] You wanna fight about it?” Beth laughed. Mother laughed. Mother twice reiterated her challenge and then called Beth an insulting name, “Come on, then, chicken.” Beth retorted by calling her mother a chicken. The two proceeded to trade insults through the next 13 turns, in the course of which Beth marked three of her utterances with teasing singsong intonation and aimed a shaming gesture (rubbing one index finger across the other) at her mother. The climax occurred after further mock provocation from the mother, when Beth finally raised her fists (to which both responded with laughter) and rushed toward her mother for an exchange of ritual blows. (P. Miller & Sperry, 1987, pp. 20–21) It is unlikely that mothers in a less difficult and dangerous neighborhood would try to promote the readiness to express aggression in their children, especially in their daughters. Thus, the norms, values, and circumstances of a culture or sub- cultural group likely contribute substantially to differences among groups in their expression of emotion. review: Children’s tendencies in regard to experiencing and regulating emotions may be affected by differences in temperament among different groups of people. These tendencies may also be influenced by differences in parenting practices, which in turn are often affected by cultural differences in beliefs about what emotions are valued, and when and where emotions should be expressed. Children’s Understanding of Emotion Another key influence on children’s emotional reactions and regulation of emotion is their understanding of emotion—that is, their understanding of how to identify emotions, as well as their understanding of what emotions mean, their social func- tions, and what factors affect emotional experience. Because an understanding of emotion affects social behavior, it is critical to the development of social compe- tence. Children’s understanding of emotions is primitive in infancy but develops rapidly over the course of childhood. Identifying the Emotions of Others The first step in the development of emotional knowledge is the recognition of different emotions in others. By 3 months of age, infants can distinguish facial expressions of happiness, surprise, and anger (Grossmann, 2010; Serrano, Iglesias, & Loeches, 1993; Walker-Andrews & Dickson, 1997). If, for example, 3- or 4-month-olds are habituated to pictures of happy faces and then are presented C H I L D R E N ’ s U N D E R s T A N D I N G O f E M O T I O N n 417 with a picture of a face depicting surprise, they dishabituate, showing renewed interest by looking longer at the new picture. By 7 months of age, infants appear to discriminate a number of additional expressions such as fear, sadness, and interest (Grossmann, 2010). For example, 7-month-olds exhibit different patterns of brain waves when they observe fearful and angry facial expressions, a finding that sug- gests some ability to discriminate these emotions (Kobiella et al., 2008). By this age or a bit earlier, infants also start to perceive others’ emotional expres- sions as meaningful. For example, if infants at this age are shown a video in which a person’s facial expression and voice are consistent in their emotional expression (e.g., a smiling face and a bubbly voice) and a video in which a person’s facial expression and voice are emotionally discrepant (e.g., a sad face and a bubbly voice), they will attend more to the presentation that is emotionally consistent (Walker- Andrews & Dickson, 1997). Infants much younger than 7 months generally do not seem to notice the difference between the two presentations. As discussed in Chapter 5, at about 5½ months of age, some children begin to demonstrate that they can relate facial expressions of emotion and emotional tones of voice to events in the environment, although this ability is often not seen until 7 to 12 months of age (Saarni et al., 2006; Vaillant-Molina & Bahrick, 2012). Such skills are evident in children’s social referencing—that is, their use of a parent’s or other adult’s facial expression or vocal cues to decide how to deal with novel, ambiguous, or possibly threatening situations. In laboratory studies of this phenomenon, infants are typically exposed to novel people or toys while their mother, at the experimenter’s direction, shows a happy, fearful, or neutral facial expression. In studies of this type, 12-month-olds tend to stay near their mother when she shows fear; to move toward the novel person or object if she expresses positive emotion; and to move partway toward the person or object if she shows no emotion (L. J. Carver & Vaccaro, 2007; Moses et al., 2001; Saarni et al., 2006). Similar results have been found in research on 12-month-olds’ ability to read their mother’s tone of voice. When prevented from seeing their mother’s face as they were being presented with novel toys, infants were more cautious and exhibited more fear when the mother’s voice was fearful than when it was neutral (Mumme, Fernald, & Herrera, 1996). By 14 months of age, the emotion-related information obtained through social referencing has an effect on children’s touching of the object even an hour later (Hertenstein & Campos, 2004). Children seem to be better at social referencing if they receive both vocal and facial cues of emotion from the adult, and vocal cues seem to be more effective than just visual cues (Vaish & Striano, 2004; Valliant- Molina & Bahrick, 2012). By the age of 3, children in laboratory studies demonstrate a rudimentary ability to label a fairly narrow range of emotional expressions displayed in pictures or on puppets’ faces (Bullock & Russell, 1985; Denham, 1986; J. A. Russell & Bullock, 1986). Young children—even 2-year-olds—are skilled at labeling happiness (usu- ally by pointing to pictures of faces that reflect happiness; Michalson & Lewis, 1985). The ability to label anger, fear, and sadness emerges and increases in the next year or two, with the ability to label surprise and disgust gradually appearing in the late preschool and early school years (N. Eisenberg, Murphy, & Shepard, 1997; J. A. Russell & Widen, 2002; Widen & Russell, 2003, 2010a). Most children cannot label more complex emotions such as pride, shame, and guilt until early to mid-elementary school (Saarni et al., 2006), but the scope and accuracy of emotion labeling improve thereafter into adolescence (Montirosso et al., 2010). The ability to discriminate and label different emotions helps children to respond appropriately to their own and others’ emotions. If a child understands social referencing n the use of a par- ent’s or other adult’s facial expression or vocal cues to decide how to deal with novel, ambiguous, or possibly threatening situations 418 n chapTer 10 EMOTIONAL DEVELOPMENT that he or she is experiencing guilt, for example, the child may understand the need to make amends to di- minish the guilt. Similarly, a child who can see that a peer is angry can devise ways to avoid or appease that peer. In fact, children who are more skilled than their peers at labeling and interpreting others’ emotions are also higher in social competence (Denham et al., 2003; R. S. Feldman, Philippot, & Custrini, 1991; Izard et al., 2008) and lower in behavior problems or social with- drawal (Alonso-Alberca et al., 2012; Fine et al., 2003; Schultz et al., 2001). Understanding the Causes and Dynamics of Emotion Knowing the causes of emotions is also important for understanding one’s own and others’ behavior and motives (Saarni et al., 2006). It likewise is key for regu- lating one’s own behavior and, hence, for social compe- tence (Denham et al., 2003; Izard et al., 2008; Schultz et al., 2001). Consider, for example, a child who is being rebuffed or insulted by a friend whom the child has just bested in a game or on an exam. If the child understands that, in this situation, the friend may be lashing out not because the friend is nasty but because the friend feels threatened and inadequate, the child may be much better able to control his or her own response. A variety of studies have shown rapid development over the preschool and school years in children’s understanding of the kinds of emotions that certain situations tend to evoke in others. In a typical study of this understanding, chil- dren are told short stories about characters in situations such as having a birthday party or losing a pet. Children are then asked how the character in the story feels. By age 3, children are quite good at identifying situations that make people feel happy. At age 4, they are fairly accurate at identifying situations that make people sad (Borke, 1971; Denham & Couchoud, 1990), and by age 5, they can identify situations likely to elicit anger, fear, or surprise (N. Eisenberg et al., 1997; Widen & Russell, 2010b). Children’s ability to understand the circumstances that evoke complex social emotions such as pride, guilt, shame, embarrassment, and jealousy often emerges after age 7, and, according to cross-cultural research that involved children from both Western nations and a remote Himalayan village, this ability is considerable by late elementary school and early adolescence (P. L. Harris et al., 1987; Widen & Russell, 2010b; Wiggers & van Lieshout, 1985). From age 4 until at least age 10, children are generally better at identifying emotions from stories depicting the cause of an emotion than from pictures of facial expressions such as fear, dis- gust, embarrassment, and shame (an exception is for surprise) (Widen & Russell, 2010a). This is probably because facial expressions of emotions such as anger, fear, sadness, and disgust are often interpreted as indicating more than one emotion (Widen & Naab, 2012). Another way to assess children’s understanding of the causes of emotions is to record what they say about emotions in their everyday conversations and to ask them to discuss and explain others’ emotions. In this kind of research, even 28-month-olds mention emotions such as happiness, sadness, anger, fear, crying, The ability to read peers’ facial expressions provides children with information about a peer’s motives, which helps children respond appropriately in potentially conflictual situations. B O B E B B E s E N / A LA M Y C H I L D R E N ’ s U N D E R s T A N D I N G O f E M O T I O N n 419 and hurting in appropriate ways in their conversations (e.g., “You sad, Daddy?” or “Don’t be mad.”) and sometimes even mention their causes (e.g., “Santa will be happy if I pee in the potty.” or “Grandma mad. I wrote on wall.”) (Bretherton & Beeghly, 1982). By age 4 to 6, children can give accurate explanations for why their peers ex- pressed negative emotions in their preschool (e.g., because they were teased or lost the use of a toy) (Fabes et al., 1988). Children get more skilled at explaining the causes of emotion across the preschool and school years (Fabes et al., 1991; Sayfan & Lagattuta, 2009; Strayer, 1986). For example, 3rd- and 6th-graders are more likely than kindergartners to believe that someone caught being dishonest will be scared (Barden et al., 1980). With age, children also come to understand that people can feel particular emo- tions brought on by reminders of past events. For instance, in one study, 3- to 5-year-olds were told stories about children who experienced a negative event and later saw reminders of that event. One story was about a girl named Mary who has a pet rabbit that lives in a typical rabbit cage. One day Mary’s rabbit is chased away by a dog and is never seen again. In different versions of the story, Mary later sees one of three reminders of her loss—the culprit dog, her rabbit’s cage, or a photo- graph of her rabbit. At this point, the children were told that Mary started to feel sad and were asked “Why did Mary start to feel sad right now?” On stories such as these, 39% of 3-year-olds, 83% of 4-year-olds, and 100% of 5-year-olds understood that the story characters were sad because a memory cue had made them think about a previous unhappy event (Lagattuta, Wellman, & Flavell, 1997). Similarly, from ages 3 to 5, children increasingly can explain that when people are in a situa- tion that reminds them of a past negative event, they may worry and change their behavior to avoid future negative events (Lagattuta, 2007). Understanding that memory cues can trigger emotions associated with past events helps children to explain their own and others’ emotional reactions in situations that in themselves seem emotionally neutral. In the elementary school years, children become increasingly sophisticated in their understanding about how, when, and why emotions occur. For example, they become more aware of cognitive processes related to regulating emotion and of the fact that emotional intensity wanes over time. They also come to recognize that people can experience more than one emotion at the same time, including both positive and negative emotions arising from the same source (P. L. Harris, 2006; Harter & Buddin, 1987; F. Pons & Harris, 2005). In addition, they increas- ingly understand how the mind can be used to both increase and reduce fears and that thinking positively can improve one’s emotion while thinking negatively can worsen it (Bamford & Lagattuta, 2012; Sayfan & Lagattuta, 2009). At around age 10, children begin to understand emotional ambivalence and realize that peo- ple can have mixed feelings about events, others, and themselves (Donaldson & Westerman, 1986; Reissland, 1985). Taken together, these developments allow children to better understand the complexities of emotional experience in context. Children’s Understanding of Real and False Emotions An important component in the development of emotional understanding is the realization that the emotions people express do not necessarily reflect their true feelings (Figure 10.4). The beginnings of this realization are seen in 3-year-olds’ occasional (and usually transparent) attempts to mask their negative emotions when they receive a disappointing gift or prize (P. M. Cole, 1986). By age 5, children’s 420 n chapTer 10 EMOTIONAL DEVELOPMENT understanding of false emotion has improved considerably, as demonstrated in a study that used six stories such as the following: Michelle is sleeping over at her cousin Johnny’s house today. Michelle forgot her fa- vorite teddy bear at home. Michelle is really sad that she forgot her teddy bear. But, she doesn’t want Johnny to see how sad she is because Johnny will call her a baby. So, Michelle tries to hide how she feels. (M. Banerjee, 1997) After children were questioned to ensure that they understood the story, they were presented with illustrations of various emotional expressions and given instructions such as “Show me the picture for how Michelle really feels” and “Show me the picture for how Michelle will try to look on her face.” Whereas about half of 3- and 4-year-olds chose the appropriate pictures on four or more of the sto- ries, more than 80% of 5-year-olds chose correctly. Studies with both Japanese and Western children also confirm that between 4 and 6 years of age, children increasingly understand that people can be misled by others’ facial expressions (D. Gardner et al., 1988; D. Gross & Harris, 1988). Part of the improvement in understanding false emotion involves a growing understanding of display rules—a social group’s informal norms about when, where, and how much one should show emotions and when and where displays of emo- tion should be suppressed or masked. Over the preschool and elementary school years, children develop a more refined understanding of when and why display rules are used (M. Banerjee, 1997; Rotenberg & Eisenberg, 1997; Saarni, 1979). They increasingly understand, for example, that people use verbal and facial display rules to protect others’ feelings or their own, as when they pretend to like someone’s cooking so as not to hurt the cook’s feelings (labeled a prosocial motive) or hide their emotions Internal feelings External expressions FIGURE 10.4 Facial display figures used in the assessment of expression regulation The figures on the girl’s chest indicate how she feels inside. children select from the different pictures of facial expressions to indicate what expression the girl would show on her face, as well as how she would feel inside. (adapted from D. c. Jones, abbey, & cumberland, 1998) display rules n a social group’s informal norms about when, where, and how much one should show emotions and when and where displays of emotion should be suppressed or masked by dis- plays of other emotions C H I L D R E N ’ s U N D E R s T A N D I N G O f E M O T I O N n 421 when they themselves are being teased or lose a contest (labeled a self-protective motive) (Gnepp & Hess, 1986). (Figure 10.5 shows age-related changes in these types of motives.) With age, children also better understand that peo- ple tend to break eye contact and avert their gaze when lying, and they are increasingly able to use this knowledge to conceal their own deception (McCarthy & Lee, 2009). These age-related advances in children’s understanding of real versus false emo- tion and display rules are apparently linked to increases in children’s cognitive capacities (Flavell, 1986; P. L. Harris, 2000). However, social factors also seem to affect children’s understanding of display rules. For example, in most cultures, display rules are somewhat different for males and females and reflect societal beliefs about how males and females should feel and behave (Ruble, Martin, & Berenbaum, 2006; van Beek, van Dolderen, & Demon Dubas, 2006). Elementary school girls in the United States, for instance, are more likely than boys to feel that openly expressing emotions such as pain is acceptable (Zeman & Garber, 1996). In most cultures, girls are also somewhat more attuned than boys to the need to in- hibit emotional displays that might hurt others’ feelings (P. M. Cole, 1986; Saarni, 1984). This is especially true for girls from cultures such as India, in which females are expected to be deferential and to express only socially appropriate emotions (M. S. Joshi & MacLean, 1994). These findings obviously are consistent with the gender stereotypes that girls are more likely both to try to protect others’ feelings and to be more emotional than boys. Parents’ beliefs and behaviors—which often reflect cultural beliefs—likely contribute to children’s understanding and use of display rules (Friedlmeier et al., 2011). As discussed earlier, the emphasis placed on controlling emotional displays in Nepal varies by subculture. Correspondingly, the degree to which Nepali chil- dren report masking negative emotions varies with the degree to which mothers in different Nepali subcultures report teaching their children how to manage emotions (P. M. Cole & Tamang, 1998). Thus, children seem to be attuned to display rules that are valued in their culture or that serve an important function in the family. review: Children’s understanding of emotions plays an important role in their emotional functioning. Although infants can detect differences in various emotional expressions such as happiness and surprise by 3 to 7 months of age, it is not until they are about 6 months of age that they start to treat others’ emotional expressions as meaningful. At about 5½ to 12 months Fifth Grade ThirdFirst Tenth 100 90 80 70 60 50 40 30 20 10 0 M ea n p ro p or ti on o f d is p la y ru le s Verbal prosocial Verbal self-protective Facial prosocial Facial self-protective FIGURE 10.5 Mean proportion of display rules as a function of mode of expression (verbal or facial), story type (prosocial or protective), and school grade children in 1st, 3rd, 5th, and 10th grade listened to stories designed to elicit display rules. Then they were asked to predict and explain what the story protagonists would say and what facial expressions the protag- onists would show in the emotion-laden situations. children’s knowledge of how and when to control emotional displays increased between 1st and 5th grade and then leveled off. Their understanding was greater for verbal display rules, whereby children monitor, falsify, and inhibit their speech, than for facial display rules. children also understood prosocial display rules (used to protect another’s feelings) better than self-protective display rules (used for personal gain). (adapted from Gnepp & hess, 1986) 422 n chapTer 10 EMOTIONAL DEVELOPMENT of age, children begin to connect facial expressions of emotion or an emotional tone of voice with other events in the situation, as evidenced by their use of social referencing. By age 3, children demonstrate a rudimentary ability to label facial expressions and understand simple situations that are likely to cause happiness. As children move through the preschool and elementary school years, their understanding of emotions and situations that cause emotions grows in range and complexity. In addition, they increasingly appreciate that the emotions people show may not reflect their true feelings. chapter summary: The Development of Emotions in Childhood n Discrete-emotions theorists believe that each emotion is pack- aged with a specific set of bodily and facial reactions and that distinct emotions are evident from early in life. In contrast, functionalists believe that emotions reflect what individuals are trying to do in specific situations—that is, their concerns and goals at the moment—and that there is not a set of innate, dis- crete emotions but many emotions based on people’s many dif- ferent interactions with the social world. n From early in life, emotions play an important role in both survival and social communication. Although infants show negative and positive affect from birth, it is not clear whether young infants experience different types of negative emotions such as anger, fear, and sadness. n Emotions undergo change in the early months and years of life. Smiles become social around the second to third month of life, and what makes children smile and laugh changes with cognitive development. n Newborns exhibit distress due to discomfort and hunger. By 6 to 7 months of age, they often are distressed when strangers approach them, and by approximately 8 months of age, they tend to get distressed when separated from their parents. n The social emotions—embarrassment, pride, shame, and guilt—emerge in the second year of life. Their emergence is tied in part to the development of a rudimentary sense of self and to an appreciation of others’ reactions to the self. n In childhood, emotional reactions are increasingly influenced by a growing cognitive understanding of events and emo- tions. For some children, there is an increase in the experience of negative emotion from childhood to adolescence. Rates of clinical and subclinical depression are much higher in adoles- cence than at younger ages, especially for girls. Regulation of Emotion n Emotional self-regulation involves the process of initiating, inhibiting, or modulating internal feeling states and emotion- related neural and physiological processes, cognitions, and behavior in the service of accomplishing one’s goals. n Young infants are not very skilled at regulating themselves and must rely on adults to manage their emotions. However, chil- dren’s self-regulation improves with age as they increasingly use cognitive strategies and more appropriate and effective means of managing their emotions and behavior. Improve- ments in children’s regulatory capacities are based on increases in both their cognitive development and their ability to control their own bodies, as well as on changes in others’ expectations of them. n Emotional self-regulation is generally associated with high social competence and low problem behavior. Individual Differences in Emotion and Its Regulation n Both biological and environmental factors contribute to the differences we see in children’s emotions and related behaviors. Temperament, which is believed to have a constitutional basis but can also be affected by social experiences, predicts adjust- ment in childhood and adulthood. However, children with dif- ficult temperaments often do well if they receive sensitive and appropriate parenting. Children’s Emotional Development in the Family n Children’s emotional development is affected by the quality of their early social relationships and their parents’ discus- sion of emotion. High levels of positive emotion in the home are associated with favorable outcomes for children, whereas high levels of negative emotion and punitive reactions to chil- dren’s displays of negative emotion are often linked to negative developmental outcomes (the latter pattern may be especially likely in Western cultures). Parental discussion of emotion or other internal states (e.g., desires, cognitions) may promote children’s understanding of emotion and increase their social competence, although the discussion of emotions per se may be less associated with social competence in some cultures. Culture and Children’s Emotional Development n There may be differences in temperament across some cul- tures, which affect children’s tendencies to experience and reg- ulate emotions. C H A P T E R s U M M A R Y n 423 n There are cultural differences in beliefs about what emotions are valued and when emotions should be expressed, and these shape children’s expression of emotion. Children’s Understanding of Emotion n To interact with others effectively, a person must be able to identify others’ emotions and have some knowledge of their causes and significance. By 5½ to 7 months of age, infants start to treat others’ emotional expressions as meaningful. Between 5½ and 12 months of age, children start to exhibit social referencing. n By age 2 to 3 years, children demonstrate a rudimentary ability to label facial expressions and simple situations associated with happiness. Children’s understanding of facial expressions, the situations that cause emotions, display rules, and the complexi- ties of emotional experience increases in the preschool and ele- mentary school years. Critical Thinking Questions 1. How might differences in children’s intelligence contribute to (a) the emotions they display and (b) their understanding of emotions? What other factors might contribute to children’s understanding of their own and others’ emotions? 2. List at least five aspects of children’s temperament. What aspects of adults’ personality might each predict? 3. Suppose that you wanted to assess changes with age in chil- dren’s regulation of emotion. Think of five different tasks you could use to assess age-related changes. Which would be best to use in early childhood and which would better reflect changes at older ages? 4. Recall from Chapter 7 the development of children’s theory of mind. How might advances in children’s understanding of theory of mind relate to their understanding of emotion? What aspects of understanding emotion might be mostly associated with an understanding of theory of mind? Key Terms behavioral inhibition, p. 409 co-rumination, p. 396 differential (or discrete) emotions theory, p. 386 display rules, p. 420 emotion, p. 385 emotional intelligence, p. 384 emotional self-regulation, p. 398 functionalist approach, p. 386 goodness of fit, p. 409 rumination, p. 396 self-conscious emotions, p. 392 separation anxiety, p. 391 social competence, p. 401 social referencing, p. 417 social smiles, p. 388 socialization, p. 411 temperament, p. 403 424 P R IV AT E C O LL E C T IO N / T H E B R ID G E M A N A R T L IB R A R Y H E C TO R M C D O N N E L L (b. 1947), Refugee Mother and Baby, Goma, 1997 (oil on canvas) 425 Attachment to Others and Development of Self n The Caregiver–Child Attachment Relationship Attachment Theory Measurement of Attachment Security in Infancy Box 11.1: Individual Differences Parental Attachment Status Cultural Variations in Attachment Factors Associated with the Security of Children’s Attachment Box 11.2: Applications Interventions and Attachment Does Security of Attachment Have Long-Term Effects? Review n Conceptions of the Self The Development of Conceptions of Self Identity in Adolescence Review n Ethnic Identity Ethnic Identity in Childhood Ethnic Identity in Adolescence Review n Sexual Identity or Orientation The Origins of Youths’ Sexual Identity Sexual Identity in Sexual-Minority Youth Review n Self-Esteem Sources of Self-Esteem Self-Esteem in Minority Children Culture and Self-Esteem Review n Chapter Summary chapter 11: 426 B etween 1937 and 1943, numerous child-care professionals in both the United States and Europe reported instances of a disturbing phenom- enon: children who seemed to have no concern or feeling for anyone but themselves. Some of the children were withdrawn and isolated; others were overactive and abusive toward their peers. By the time they were adolescents, these children often had histories of persistent stealing, violence, and sexual misdemeanors. Many of these children had been reared in institutions in which they received adequate physical care but experienced little social interaction; others had been shifted from foster home to foster home in infancy and early child- hood (Bowlby, 1953). At about the same time, similar disturbances were being observed among chil- dren who had been orphaned or separated from their parents during World War II and were in refugee camps or other institutional settings. John Bowlby, an English psychoanalyst who worked with many of these children, reported that they were very listless, depressed or otherwise emotionally disturbed, and mentally stunted. Older refugee children often seemed to have lost all interest in life and were pos- sessed by feelings of emptiness (Bowlby, 1953). These children, like the Romanian orphans discussed in Chapter 1 (pages 6–7) tended not to develop normal emo- tional attachments with other people. On the basis of such observations, René Spitz, a French psychoanalyst who had worked with Freud, conducted a series of classic studies of how the lack of adequate caregiving affects development (Spitz, 1945, 1946, 1949). Spitz filmed infants (a methodological innovation) residing in orphanages, most of whom had been born to unmarried mothers and had been given up for adoption. The films were extremely poignant and painful to watch. They documented the fact that, despite receiving good institutional care, the infants were generally sickly and develop- mentally impaired. In many cases, the infants seemed unmotivated to live: their death rate was about 37% over 2 years’ time, compared with no deaths in an insti- tution where children had daily contact with their mothers. The films’ most impor- tant contribution, however, was their evidence of intense and prolonged grief and depression in infants who had been separated from their mothers after developing a loving relationship with them. Psychologists of the time did not believe that infants could experience such emotions (Emde, 1994). Taken together, these early observations also challenged the more central belief, then held by many child-care professionals, that if children in institutions such as orphanages received good physical care, including proper nourishment and health care, they would develop normally. These professionals placed little emphasis on the emotional dimensions of caregiving. As a result of the studies of children who lost their parents in the 1940s, it became generally recognized that, no matter how hygienic and competently managed, institutions like orphanages put babies at high risk because they did not provide the kind of caregiving that enables infants to form close socioemotional bonds. Adoption—the earlier the better—came to be viewed as a far better option. Another important outcome of the work of Bowlby and others who studied institutionalized children was the beginning of systematic research on how the quality of parent–child interactions affects children’s development in families, especially their development of emotional attachments to other people. This research, which continues today, has led to a much deeper understanding of the ways in which the early parent–child emotional bond likely influences children’s Themes n Nature and Nurture n The Active Child n The Sociocultural Context n Individual Differences n Research and Children’s Welfare T H E C A R E G I V E R – C H I L D A T T A C H M E N T R E L A T I O N s H I P n 427 interactions with others from infancy into adulthood. It has also provided new insight into the development of children’s sense of self, as well as of their emotions, including their feelings of self-worth. In this chapter, we will first explore how children develop attachments, close and enduring emotional bonds to parents or other primary caregivers. Then we will examine the ways in which the nature of these attachments to others seems to set the stage for the child’s near- and long-term development. As you will see, the attachment process appears to be biologically based yet unfolds in different ways, depending on the familial and cultural context. Thus, the themes of nature and nur- ture and the sociocultural context will be important in our discussion of this topic. You will also see that although most children in normal social circumstances develop attachments to their parents, the quality of these attachments differs in important ways and has implications for each child’s social and emotional development. The theme of individual differences will therefore figure prominently in our discussion as well. The theme of research and children’s welfare is also relevant to our examination of experi- mental interventions designed to enhance the quality of mother–child attachment. Next we will examine a related issue—the development of children’s sense of self, that is, their self-understanding, self-identity, and self-esteem. Although many factors influence these areas of development, the quality of children’s early attach- ments lays the foundation for how children feel about themselves, including their sense of security and well-being. Over time, children’s self-understanding, self- esteem, and self-identity are also shaped by how others perceive and treat them, by biologically based characteristics of the child, and by children’s developing abilities to think about and interpret their social worlds. Thus, the themes of nature and nurture, individual differences, the sociocultural context, and the active child will be evident in our discussion of the development of self. The Caregiver–Child Attachment Relationship Following the very disturbing observations made in the 1930s and 1940s regarding children separated from their parents early in life, researchers began to conduct sys- tematic studies of this phenomenon. Much of the early research, such as that con- ducted by Spitz, focused on how the development of young children who had been orphaned or otherwise separated from their parents was affected by the quality of the caregiving they subsequently received. The research on children adopted from Romania (discussed in Chapter 1) is probably the best known of recent studies on this topic, all of which support the idea that institutional care in the first years of life typically hin- ders optimal social, emotional, and cognitive development (McCall et al., 2011; Rutter et al., 2010). Another line of research in this area involved experimen- tal work with monkeys. In some of the most famous research in psychology, Harry Harlow and his colleagues (Harlow & Harlow, 1965; Harlow & Zimmerman, 1959; E. E. Nelson, Herman, et al., 2009; L. D. Young et al., 1973) reared infant rhesus monkeys in isolation from birth, comparing their de- velopment with that of monkeys reared normally with their mothers. The isolated babies were well fed and kept healthy, but they had no exposure to their mother or other monkeys. Harlow’s female monkeys who were raised in isolation were poor mothers as adults, turning their backs on their infants, literally and figuratively, and often attacking them. This outcome suggested that “mother love” is essential to normal social and emotional development. H A R LO W P R IM AT E L A B O R AT O R Y, U N IV E R s IT Y O F W Is C O N s IN attachment n an emotional bond with a specific person that is enduring across space and time. Usually, attachments are discussed in regard to the rela- tion between infants and specific care- givers, although they can also occur in adulthood. 428 n cHapTer 11 ATTACHMENT TO OTHERs AND DEVELOPMENT OF sELF When they finally were placed with other monkeys 6 months later, they compul- sively bit and rocked themselves and avoided other monkeys completely, appar- ently incapable of communicating with, or learning from, others. They also showed high levels of fear when exposed to threatening stimuli such as a loud sound. As adults, formerly isolated females had no interest in sex. If they were artificially impregnated, they did not know what to do with their babies. At best, they tended to ignore or reject them; at worst, they attacked them. This research, although examining the effects of the lack of all early social interaction (and not just that with parents), strongly supported the view that children’s healthy social and emo- tional development is rooted in their early social interactions with adults. Attachment Theory The findings from observations of children and monkeys separated from their parents were so dramatic that psychiatrists and psychologists were compelled to rethink their ideas about early development. Foremost in this effort were John Bowlby, who proposed attachment theory, and his colleague, Mary Ainsworth, who extended and tested Bowlby’s ideas. Bowlby’s Attachment Theory Bowlby’s theory of attachment was strongly influenced by several key tenets of Freud’s theories, especially the idea that infants’ earliest relationships with their mothers shape their later development. However, Bowlby replaced the psycho- analytic notion of a “needy, dependent infant” with the idea of a “competence- motivated infant” who uses his or her primary caregiver as a secure base (E. Waters & Cummings, 2000). The general idea of the secure base is that the presence of a trusted caregiver provides the infant or toddler with a sense of security that allows the child to explore the environment and hence to become generally knowledgeable and competent. In addition, the primary caregiver serves as a haven of safety when the infant feels threatened or insecure, and the child derives comfort and pleasure from being near the caregiver. Bowlby’s idea of the primary caregiver as a secure base was directly influenced by ethological theories, particularly the ideas of Konrad Lorenz (see Chapter 9, page 363). Bowlby proposed that the attach- ment process between infant and care- giver is rooted in evolution and increases the infant’s chance of survival. Just like imprinting, this attachment process devel- ops from the interaction between species- specific learning biases (such as infants’ strong tendency to look at faces) and the infant’s experience with his or her care- giver. Thus, the attachment process is viewed as having an innate basis, but the development and quality of infants’ attach- ments are highly dependent on the nature of their experiences with caregivers. attachment theory n theory based on John Bowlby’s work that posits that children are biologically predisposed to develop attachments to caregivers as a means of increasing the chances of their own survival secure base n refers to the idea that the presence of a trusted caregiver provides an infant or toddler with a sense of secu- rity that makes it possible for the child to explore the environment John Bowlby, who laid the foundations of attachment theory, was influenced by psy- choanalytic work and research on animals’ social behavior. CO U R T E s Y s IR R IC H A R D B O W LB Y T H E C A R E G I V E R – C H I L D A T T A C H M E N T R E L A T I O N s H I P n 429 According to Bowlby, the initial development of attachment takes place in four phases. n Preattachment (birth to age 6 weeks). In this phase, the infant produces innate signals, most notably crying, that summon caregivers, and the infant is com- forted by the ensuing interaction. n Attachment-in-the-making (age 6 weeks to 6 to 8 months). During this phase, infants begin to respond preferentially to familiar people. Typically they smile, laugh, or babble more frequently in the presence of their primary caregiver and are more easily soothed by that person. Like Freud and Erik Erikson, Bowlby saw this phase as a time when infants form expectations about how their care- givers will respond to their needs and, accordingly, do or do not develop a sense of trust in them. n Clear-cut attachment (between 6 to 8 months and 1½ years). In this phase, infants actively seek contact with their regular caregivers. They happily greet their mother when she appears and, correspondingly, may exhibit separa- tion anxiety or distress when she departs (see Chapter 10, page 391). For the majority of children, the mother now serves as a secure base, facilitating the infant’s exploration and mastery of the environment. n Reciprocal relationships (from 1½ or 2 years on). During this final phase, tod- dlers’ rapidly increasing cognitive and language abilities enable them to under- stand their parents’ feelings, goals, and motives and to use this understanding to organize their efforts to be near their parents. As a result, a more mutu- ally regulated relationship gradually emerges as the child takes an increas- ingly active role in developing a working partnership with his or her parents (Bowlby, 1969). Correspondingly, separation distress declines. The usual outcome of these phases is an enduring emotional tie uniting the infant and caregiver. In addition, the child develops an internal working model of attachment, a mental representation of the self, of attachment figures, and of relationships in general. This internal working model is based on the young child’s discovering the extent to which his or her caregiver could be depended on to satisfy the child’s needs and provide a sense of security. Bowlby believed that this internal working model guides the individual’s expectations about relationships through- out life. If caregivers are accessible and responsive, young children come to expect interpersonal relationships to be gratifying and they feel worthy of receiving care and love. As adults, they look for, and expect to find, satisfying and security- enhancing relationships similar to the ones they had with their attachment fig- ures in childhood. If children’s attachment figures are unavailable or unresponsive, children develop negative perceptions of relationships with other people and of themselves (Bowlby, 1973, 1980; Bretherton & Munholland, 1999). Thus, chil- dren’s internal working models of attachment are believed to influence their overall adjustment, social behavior, perceptions of others, and the development of their self-esteem and sense of self (R. A. Thompson, 2006). Ainsworth’s Research Mary Ainsworth, who began working with John Bowlby in 1950, provided empirical support for Bowlby’s theory, extending it in important ways and bring- ing the concept of the primary caregiver as a secure base to the fore. In research conducted in both Uganda (Ainsworth, 1967) and the United States, Ainsworth internal working model of attach- ment n the child’s mental representation of the self, of attachment figure(s), and of relationships in general that is con- structed as a result of experiences with caregivers. The working model guides children’s interactions with caregivers and other people in infancy and at older ages. 430 n cHapTer 11 ATTACHMENT TO OTHERs AND DEVELOPMENT OF sELF studied mother–infant interactions during infants’ explorations and separations from their mother. On the basis of her observations, she came to the conclusion that two key measures provide insight into the quality of the infant’s attach- ment to the caregiver: (1) the extent to which an infant is able to use his or her primary caregiver as a secure base, and (2) how the infant reacts to brief sepa- rations from, and reunions with, the caregiver (Ainsworth, 1973; Ainsworth et al., 1978). Measurement of Attachment Security in Infancy With these measures in mind, Ainsworth designed a laboratory test for assessing the security of an infant’s attachment to his or her parent. This test is called the Strange Situation because it is conducted in a context that is unfamiliar to the child and likely to heighten the child’s need for his or her parent. In this test, the infant, accompanied by the parent, is placed in a laboratory playroom equipped with in- teresting toys. After the experimenter introduces the parent and child to the room, the child is exposed to seven episodes, including two separations from, and reunions with, the parent, as well as two interactions with a stranger—one when the parent is out of the room and one when the parent is present (see Table 11.1). Each episode lasts approximately 3 minutes unless the child becomes overly upset. Throughout these episodes, observers rate infants’ behaviors, including their attempts to seek closeness and contact with the parent, their resistance to or avoidance of the parent, their interactions with the stranger, and their interactions with the parent from a dis- tance using language or gestures. TABLE 11.1 episodes in ainsworth’s Strange Situation procedure Episode Events Aspect of Attachment Behavior Assessed 1 Experimenter introduces caregiver and infant to the unfamiliar room; shows toys to baby; then leaves. None 2 Caregiver and child are alone; caregiver is told not to initiate interaction but to respond to baby as appropriate. Exploration and use of parent as a secure base 3 Stranger enters and is seated quietly for 1 minute; then talks to caregiver for 1 minute; then tries to interact with the baby for 1 minute. Reaction to the stranger 4 Mother leaves child alone with the stranger, who lets baby play but offers comfort if needed. Segment is shortened if the baby becomes too distressed. Separation distress and reaction to stranger’s comforting 5 Caregiver calls to baby from outside door, enters the room, and pauses by the door. Stranger leaves. Caregiver lets infant play or may comfort infant if distressed. Reaction to reunion with parent 6 Parent leaves infant alone in the room. Segment is ended if infant is too distressed. Separation distress 7 Stranger enters room, greets infant, and pauses. She sits or comforts infant if the infant is upset. Segment is ended if the infant is very upset. Ability to be soothed by stranger 8 Caregiver calls from outside the door, enters and greets infant and pauses. Caregiver sits if infant is not upset but may provide comfort if infant is distressed. Caregiver allows infant to return to play if interested. Reaction to reunion Source: Adapted from Ainsworth et al. (1978) Strange Situation n a procedure devel- oped by Mary Ainsworth to assess infants’ attachment to their primary caregiver T H E C A R E G I V E R – C H I L D A T T A C H M E N T R E L A T I O N s H I P n 431 Through her use of the Strange Situation, Ainsworth (1973) discerned three distinct patterns in infants’ behavior that seemed to indicate the quality or security of their attachment bond. These patterns—which are reflected in the infant’s behavior throughout the Strange Situation, but especially during the reunions with the parent—have been replicated many times in research with mothers, and sometimes with fathers. On the basis of these patterns, Ainsworth identified three attachment categories. The first attachment category—the one into which the majority of infants fall—is secure attachment. Babies in this category use their mother as a secure base dur- ing the initial part of the session, leaving her side to explore the many toys avail- able in the room. As they play with the toys, these infants occasionally look back to check on their mother or bring a toy over to show her. They are usually, but by no means always, distressed to some degree when their mother leaves the room, especially when they are left totally alone. However, when their mother returns, they make it clear that they are glad to see her, either by simply greeting her with a happy smile or, if they have been upset during her absence, by going to her to be picked up and comforted. If they have been upset, their mother’s presence comforts and calms them, often enabling them to explore the room again. About 62% of typical middle-class children in the United States whose mother is not clinically disturbed fall into this category; for infants from lower socioeconomic groups, the rate is sig- nificantly lower—slightly less than 50% for children under 24 months of age (R. A. Thompson, 1998; van IJzendoorn, Schuengel, & Bakermans-Kranenburg, 1999). The other two attachment categories that Ainsworth originally identified in- volve children who are rated as insecurely attached, that is, who have less positive attachment to their caregivers than do securely attached children. One type of in- securely attached infant is classified as insecure/resistant, or ambivalent. Infants in this category are often clingy from the beginning of the Strange Situation, stay- ing close to the mother instead of exploring the toys. When their mother leaves the room, they tend to get very upset, often crying intensely. In the reunion, the insecure/resistant infant typically re-establishes contact with the mother, only to then rebuff her efforts at offering comfort. For example, the infant may rush to the mother bawling, with outstretched arms, signaling the wish to be picked up—but then, as soon as he or she is picked up, arch away from the mother or begin squirm- ing to get free from her embrace. About 9% of typical middle-class children in the United States fall into the insecure/resistant category, but the percentage appears to be somewhat higher in many non-Western cultures (van IJzendoorn et al., 1999). The other type of insecurely attached infant is classified as insecure/avoidant. Children in this category tend to avoid their mother in the Strange Situation. For example, they often fail to greet her during the reunions and ignore her or turn away while she is in the room. Approximately 15% of typical middle-class children fall into the insecure/avoidant category (van IJzendoorn et al., 1999). Subsequent to Ainsworth’s original research, attachment investigators found that the reactions of a small percentage of children in the Strange Situation did not fit well into any of Ainsworth’s three categories. These children seem to have no consistent way of coping with the stress of the Strange Situation. Their behav- ior is often confused or even contradictory. For example, they may exhibit fearful smiles and look away while approaching their mother, or they may seem quite calm and contented and then suddenly display angry distress. They also frequently ap- pear dazed or disoriented and may freeze in their behavior and remain still for a substantial period of time. These infants, labeled disorganized/disoriented, seem secure attachment n a pattern of attachment in which infants or young children have a high-quality, relatively unambivalent relationship with their attachment figure. In the Strange Situ- ation, a securely attached infant, for example, may be upset when the care- giver leaves but may be happy to see the caregiver return, recovering quickly from any distress. When children are securely attached, they can use caregivers as a secure base for exploration. insecure attachment n a pattern of attachment in which infants or young children have a less positive attach- ment to their caregiver than do securely attached children. Insecurely attached children can be classified as insecure/ resistant (ambivalent), insecure/avoidant, or disorganized/disoriented. insecure/resistant (or ambivalent) attachment n a type of insecure attach- ment in which infants or young children are clingy and stay close to their caregiver rather than exploring their environment. In the Strange Situation, insecure/resis- tant infants tend to get very upset when the caregiver leaves them alone in the room. When their caregiver returns, they are not easily comforted and both seek comfort and resist efforts by the caregiver to comfort them. insecure/avoidant attachment n a type of insecure attachment in which infants or young children seem somewhat indifferent toward their caregiver and may even avoid the caregiver. In the Strange Situation, they seem indifferent toward their caregiver before the caregiver leaves the room and indifferent or avoidant when the caregiver returns. If the infant gets upset when left alone, he or she is as easily comforted by a stranger as by a parent. disorganized/disoriented attachment n a type of insecure attachment in which infants or young children have no consis- tent way of coping with the stress of the Strange Situation. Their behavior is often confused or even contradictory, and they often appear dazed or disoriented. 432 n cHapTer 11 ATTACHMENT TO OTHERs AND DEVELOPMENT OF sELF to have an unsolvable problem: they want to approach their mother, but they also seem to regard her as a source of fear from which they want to withdraw (Main & Solomon, 1990). About 15% of middle-class American infants fall into this cat- egory. However, this percentage may be considerably higher among maltreated infants (van IJzendoorn et al., 1999), among infants whose parents are having serious difficulties with their own working models of attachment (van IJzendoorn, 1995) (see Box 11.1), and among preschoolers from lower socioeconomic back- grounds (Moss, Cyr, & Dubois-Comtois, 2004; van IJzendoorn et al., 1999). A key question, of course, is whether there is some similarity between in- fants’ behavior in the Strange Situation and their behavior at home. The answer According to attachment theorists, parents have “working models” of attachment rela- tionships that guide their interactions with their children and thereby influence the se- curity of their children’s attachment. These adult attachment models are based on adults’ perceptions of their own childhood relation- ships with their parents and on the continu- ing influence of those relationships (Main, Kaplan, & Cassidy, 1985). Parental models of attachment often are measured with the Adult Attachment Inter- view (AAI), developed by Mary Main, Carol George, and their colleagues. In this inter- view, adults are asked to discuss their early childhood attachments and to evaluate them from their current perspectives (Hesse, 1999). For example, they are asked to de- scribe their childhood relationship with each parent, including what their parent did for them when they were hurt or upset; what they remember about separations from the par- ent; if they ever felt rejected by the parent; and how their adult personalities were shaped by these experiences. These descriptions are used to classify the adults into four major at- tachment groups—autonomous (or secure), dismissing, preoccupied, and unresolved/ disorganized. Adults who are rated autonomous, or secure, are those whose descriptions are coherent, consistent, and relevant to the questions. Generally, autonomous adults describe their past in a balanced manner, recalling both positive and negative features of their parents and of their relationships with them. They also report that their early attachments were influential in their devel- opment. Autonomous adults discuss their past in a consistent and coherent manner even if they did not have supportive parents. Adults in the other three categories are considered to be insecure in their attach- ment status. Dismissing adults often insist that they cannot remember attachment- related interactions with their parents, or they minimize the impact that these experi- ences had on them. They may also contradict themselves when describing their attach- ment-related experiences and seem unaware of their inconsistencies. For example, they may describe their mother in glowing terms and later talk about how she got angry at them whenever they hurt themselves (Hesse, 1999). Preoccupied adults are intensely focused on their parents and tend to give confused and angry accounts of attachment-related ex- periences. A prototypical response is “I got so angry [at my mother] that I picked up the soup bowl and threw it at her” (Hesse, 1999, p. 403). Preoccupied adults often seem to be so caught up in their attachment memories that they cannot provide a coherent description of them. Unresolved/disorganized adults appear to be suffering the aftermath of past traumatic experiences of loss or abuse. Their descrip- tions of their childhood show striking lapses in reasoning and may not make sense. For ex- ample, an unresolved/disorganized adult may indicate that he or she believes that a dead parent is still alive or that the parent died because of negative thoughts that the adult had about the parent (Hesse, 1999). In North American samples of White mothers who have no diagnosed psychological dis- turbance, approximately 58% are classified as secure, 23% as dismissing, and 19% as preoccupied. This distribution is gener- ally similar in samples in other countries such as India, China, and in countries in Africa and South America (van IJzendoorn & Bakermans-Kranenburg, 2010). Parents’ attachment classification pre- dicts both their sensitivity toward their own children and their children’s attachment to them. Autonomous parents tend to be sen- sitive, warm parents, and their infants usu- ally are securely attached to them (Magai et al., 2000; Steele, Steele, & Fonagy, 1996; van IJzendoorn, 1995). Correspond- ingly, parents in the other three categories tend to have insecurely attached infants, although the relation is not very strong for preoccupied parents (see figure). Unre- solved parents are particularly likely to have disorganized infants (Hesse & Main, 2006; Madigan et al., 2007), probably due, in part, to their low sensitivity as parents, in- cluding either a negative and controlling, or a disengaged and inattentive, style of par- enting (H. N. Bailey et al., 2007; Busch, Cowan, & Cowan, 2008; Whipple, Bernier, & Mageau, 2011). This general pattern of findings has emerged in studies in a number of different Western cultures (Hesse, 1999). The reason for the association between parents’ attachment models and the secu- rity of their children’s attachments is not clear. Autonomous parents appear to be more sensitively attuned to their children, BOX 11.1: individual differences PARENTAL ATTACHMENT STATUS adult attachment models n working models of attachment in adulthood that are believed to be based on adults’ per- ceptions of their own childhood experi- ences—especially their relationships with their parents—and of the influence of these experiences on them as adults T H E C A R E G I V E R – C H I L D A T T A C H M E N T R E L A T I O N s H I P n 433 is yes ( J. Solomon & George, 1999). For example, compared with infants who are insecurely attached, 12-month-olds who are securely attached exhibit more enjoyment of physical contact, are less fussy or difficult, and are better able to use their mothers as a secure base for exploration at home (Pederson & Moran, 1996). Thus, they are more likely to learn about their environments and to enjoy doing so. In addition, children’s behavior in the Strange Situation correlates with attachment scores derived from observing children’s interactions with their mother over several hours (van IJzendoorn et al., 2004). As you will shortly see, attachment measurements derived from the Strange Situation also correlate with later behavior patterns. which likely contributes to their children’s being securely attached (Mills-Koonce et al., 2011; Pederson et al., 1998; Verschueren et al., 2006). For example, securely attached parents are less angry and intrusive in their interactions with their children than are preoccupied parents (Adam, Gunnar, & Tanaka, 2004). And it may very well be that autonomous adults, who tend to have been securely attached as infants or children (E. Waters, et al., 2000), are more sensi- tive and skilled parents because of their own early experience with sensitive parent- ing (Benoit & Parker, 1994), although the evidence for this is somewhat inconsistent (H. N. Bailey et al., 2007). However, it is not clear what adults’ responses on the AAI actually represent. Although attachment theorists claim that the content and coherence of adults’ discussions of their own early childhood experiences reflect the effects of these early experiences, there is little evidence to prove (or disprove) this theory (Fox, 1995; R. A. Thompson, 1998). Rather than reflecting their own childhood experiences, adults’ discussions of them may instead reflect their personal theories about development and child rear- ing, their current level of psychological func- tioning, or their personality—all of which also may affect their parenting. Regardless of the reason, the relation between parents’ attach- ment models and their infants’ attachment suggests that parents’ beliefs about parent- ing and about relationships have a power- ful influence on the bond between them and their children (R. A. Thompson, 1998). Autonomous parents 73% Securely attached infants Anxious/avoidant attached infants Anxious/resistant infants Disorganized infants Preoccupied parents 5% Dismissing parents 8% Unresolved parents 14% Preoccupied parents 36% Dismissing parents 11% Unresolved parents 21% Autonomous parents 32% Dismissing parents 53% Dismissing parents 16% Unresolved parents 25% Unresolved parents 53% Pre- occupied parents 12% Pre- occupied parents 9% Autonomous parents 10% Autonomous parents 22% parents with secure adult attachments tend to have securely attached children. (adapted from van IJzendoorn, 1995) 434 n cHapTer 11 ATTACHMENT TO OTHERs AND DEVELOPMENT OF sELF Cultural Variations in Attachment Because human infants are believed to be biologically predisposed to form attach- ments with their caregivers, one might expect attachment behaviors to be similar in different cultures. In fact, in large measure, infants’ behaviors in the Strange Situation are similar across numerous cultures, including those of China, west- ern Europe, and various parts of Africa. In all these cultures, there are securely attached, insecure/resistant, and insecure/avoidant infants, with the average per- centages for these groupings being approximately 53%, 18%, and 21%, respectively (van IJzendoorn & Sagi, 1999; van IJzendoorn et al., 1999). Although relatively few studies in non-Western cultures have included the category “disorganized/ disoriented,” the findings of those that have suggest that the percentage of babies who fall into this category is roughly 21%, which is not statistically different from the rates in Western countries (Behrens, Hesse, & Main, 2007; van IJzendoorn et al., 1999). Despite these general consistencies in attachment ratings, some interesting and important differences in children’s behavior in the Strange Situation have been noted in certain other cultures (van IJzendoorn & Sagi-Schwartz, 2008; Zevalkink, Riksen-Walraven, & Van Lieshout, 1999). For example, while Japanese infants in one study showed roughly the same percentage of secure attachment in the Strange Situation as middle-class U.S. infants do (about 62% to 68%), in some research, there was a notable difference in the types of insecure attachment they displayed. All the inse- curely attached Japanese infants were classified as insecure/resistant, which is to say that none exhibited insecure/avoidant behavior (Takahashi, 1986). Similarly, in a sample of Korean families, insecure/avoidant children were very rare ( Jin et al., 2012). One possible explanation for this is that Japanese culture exalts the idea of oneness between mother and child; correspondingly, its child-rearing practices, compared with those in the United States, foster greater mother– infant closeness and physical intimacy, as well as infants’ greater dependency on their mother (Rothbaum et al., 2000). Thus, in the Strange Situation, Japanese children may desire more bodily contact and reassurance than do U.S. children and therefore may be more likely to exhibit anger and resis- tance to their mother after being deprived of contact with her (Mizuta et al., 1996). Another explanation is that the Strange Situation might not always have been a valid measure because it is possible that some Japanese parents were self- conscious and inhibited in the Strange Situation setting, which, in turn, could have affected their children’s behavior. It is also possible that how young children react in the Strange Situation is affected by their prior experience with unfamiliar situ- ations and people. Thus, part of the difference in the rates of insecure/resistant attachment shown by Japanese and U.S. infants may be due to the fact that, at the time that many of the studies in question were conducted (the 1980s), very few infants in Japan were enrolled in day care and thus did not experience frequent separations from their mother. Consistent with this argument, a more recent study, which looked at the reunion behaviors of 6-year-old Japanese children who had all attended preschool, did not find a high number of insecure/resistant attachments (Behrens, Hesse, & Main, 2007). It is therefore possible that differences in chil- dren’s experiences with separation within or across cultures contribute substantially to the variability in children’s behavior in the Strange Situation. The degree to which children are encour- aged to be independent varies across cul- tures and can affect whether children are categorized as insecure/resistant. s T E V E N s O N P H O T O G R A P H Y. C O M T H E C A R E G I V E R – C H I L D A T T A C H M E N T R E L A T I O N s H I P n 435 Factors Associated with the Security of Children’s Attachment One obvious question that arises in trying to explain differences in attachment patterns is whether the par- ents of securely attached and insecurely attached chil- dren differ in the way they interact with their children. Evidence suggests that they do. Parental Sensitivity Attachment theorists have argued that the most cru- cial parental factor contributing to the development of a secure attachment is parental sensitivity (Ainsworth et al., 1978). One key aspect of parental sensitivity is consistently responsive care giving. The mothers of securely attached 1-year-olds tend to read their babies’ signals accurately, responding quickly to the needs of a crying baby and smil- ing back at a beaming one. Positive exchanges between mother and child, such as mutual smiling and laughing, making sounds at each other, or engaging in coor- dinated play, are a characteristic of sensitive parenting that may be particularly important in promoting secure attachment (De Wolff & van IJzendoorn, 1997; Nievar & Becker, 2008). In contrast, the mothers of insecure/resistant infants tend to be inconsistent in their early caregiving: they sometimes respond promptly to their infants’ dis- tress, but sometimes they do not. These mothers often seem highly anxious and overwhelmed by the demands of caregiving. Mothers of insecure/avoidant infants tend to be indifferent and emotionally unavailable, sometimes rejecting their baby’s attempts at physical closeness (Isabella, 1993; Leerkes, Parade, & Gudmundson, 2011). Mothers of disorganized/distressed infants sometimes exhibit abusive, fright- ening, or disoriented behavior and may be dealing with unresolved loss or trauma (L. M. Forbes et al., 2007; Madigan, Moran, & Pederson, 2006; van IJzendoorn et al., 1999). In response, their infants often appear to be confused or frightened (E. A. Carlson, 1998; Hesse & Main, 2006). By age 3 to 6, perhaps in an attempt to manage their emotions, these children often try to control their mother’s activities and conversation, either in an excessively helpful and emotionally positive way, ba- sically trying to cheer her up, or in a hostile or aggressive way (Moss et al., 2004; J. Solomon, George, & De Jong, 1995). The association between maternal sensitivity and the quality of infants’ and chil- dren’s attachment has been demonstrated in numerous studies involving a variety of cultural groups (Beijersbergen et al., 2012; Mesman et al., 2012; Posada et al., 2004; Valenzuela, 1997; van IJzendoorn et al., 2004). Particularly striking is the finding that infants whose mothers are insensitive show only a 38% rate of secure attachment, which is much lower than the typical rate (van IJzendoorn & Sagi, 1999). An association between fathers’ sensitivity and the security of their children’s attachment has also been found, though it is somewhat weaker than that for mothers (G. L. Brown, Mangelsdorf, & Neff, 2012; Lucassen et al., 2011; van IJzendoorn & De Wolff, 1997). Given that all the research discussed above involves correlations between parental sensitivity and children’s attachment status, it is impossible to determine The mothers of securely attached infants generally respond warmly to their offspring and are sensitive to their needs. C U LT U R A C R E AT IV E / A LA M Y parental sensitivity n an important factor contributing to the security of an infant’s attachment. Parental sensitivity can be exhibited in a variety of ways, including responsive caregiving when an infant is distressed or upset and engaging in coordinated play with the infant. 436 n cHapTer 11 ATTACHMENT TO OTHERs AND DEVELOPMENT OF sELF whether parents’ sensitivity was actually responsible for their children’s security of attachment or was merely associated with it. It could be that some other fac- tor, such as the presence or absence of marital conflict, affected both the parents’ sensitivity and the child’s security of attachment. However, evidence that parental sensitivity does in fact have a causal effect on infants’ attachment has been provided by short-term experimental interventions designed to enhance the sensitivity of mothers’ caregiving. These interventions, discussed in Box 11.2, have been found to increase not only mothers’ sensitivity with their infants but also the security of their infants’ attachment (Bakermans-Kranenburg, van IJzendoorn, & Juffer, 2003; van IJzendoorn, Juffer, & Duyvesteyn, 1995). Moreover, in twin studies of infants’ attachment, nearly all the variation in attachments was due to environmental fac- tors (Bokhorst et al., 2003; Roisman & Fraley, 2008). Nonetheless, recent research findings indicate that some individual differences in attachment behaviors may be linked in complex ways to specific genes (S. C. Johnson & Chen, 2011). One study, for instance, focused on the possible influence To determine whether parental sensitivity is causally related to differences in security of attachment, researchers have designed special intervention studies. In these stud- ies, parents in an experimental group are first trained to be more sensitive in their caregiving. Later, the attachment statuses of their infants are compared with those of children whose parents, as members of a control group, experienced no intervention (van IJzendoorn et al., 1995). An intervention study of this sort was con- ducted in the Netherlands by Daphna van den Boom (1994, 1995). Infants who were rated as irritable shortly after their birth were selected for the study because some investigators (but not all) have found that irritable infants may be at risk for insecure attachment. When the infants were about 6 months of age, half of their mothers were randomly chosen to be in the experimen- tal group for three months. These mothers were taught to be attuned to their infants’ cues regarding their wants and needs and to respond to them in a manner that fostered positive exchanges between mother and child. The remaining mothers in the control group received no special training. At the end of the intervention, mothers in the experimental group were more attentive, responsive, and stimulating to their infants than were those in the control group. In turn, their infants were more sociable, explored the environment more, were better able to soothe themselves, and cried less than infants whose mothers did not receive the intervention. Especially significant, the rates of secure attachment were nota- bly higher for infants whose mothers were in the experimental group—62% compared with 22%. In a longitudinal follow-up at 18 months of age, 72% of the children in the interven- tion group were securely attached, compared with 26% of the children in the control group. When their infants were 24 months old, mothers in the intervention group were, as earlier, more accepting, accessible, cooperative, and sensitive with their infants than were the control-group mothers, and their children were more cooperative. Simi- lar findings were obtained when the children were 3½ years old. Experimental interventions have also been used to improve depressed moth- ers’ attachments to their children. The as- sumption underlying these interventions is that depressed mothers, whose relation- ship with their children is often impaired, can be taught skills and information that improve the quality of the mother–infant relationship. In one study, for example, investigators taught depressed mothers parenting skills and provided them with information about child development to enhance their coping and social-support skills (Toth et al., 2006). In another study (van Doesum et al., 2008), depressed mothers were videotaped bathing or feeding their infant and then, after viewing the film, were trained to respond to the infant with more sensitive and appropriate communica- tive behaviors. In addition, this intervention included such techniques as having a home visitor model positive caregiving, encour- aging the mother to change her negative patterns of thinking about her infant and about her own parenting skills, and provid- ing practical information on child devel- opment. Both studies were successful in improving the quality of the mother– infant attachment relationship. Other interventions that used similar techniques have also succeeded in reduc- ing the rate of disorganized attachment, and increasing the rate of secure attachment, for children who were at risk for maternal mal- treatment (Bernard et al., 2012; Moss et al., 2011). From the evidence of experimental studies such as these, it seems clear that sensitive parenting contributes to infants’ and young children’s security of attachment. BOX 11.2: applications INTERVENTIONS AND ATTACHMENT T H E C A R E G I V E R – C H I L D A T T A C H M E N T R E L A T I O N s H I P n 437 that allelic variants of the serotonin transporter gene, SLC6A4 (formerly named 5HTT), might have on behavior in the Strange Situation. The participants were Ukrainian preschoolers, some of whom had been raised in institutions and some of whom had been raised in their biological family. The researchers found that chil- dren with a SLC6A4 variant frequently associated with reactivity and vulnerability in the face of stress exhibited less attachment security and more attachment dis- organization if they grew up in an institution than did preschoolers with the same variant who lived with their family. In contrast, preschoolers who were raised in an institution but had a different SLC6A4 genotype, one that is frequently associated with less reactivity and less vulnerability, did not exhibit adverse attachment behav- ior (Bakermans- Kranenburg, Dobrova-Krol, & van IJzendoorn, 2012). There is also some research indicating that a gene involved in the dopa- mine system, called DRD4, is associated with disorganized attachment when an infant is in a stressful environment (as when the mother is suffering from trauma or loss) but is associated with greater attachment security in a less stressful context (Bakermans-Kranenburg & van IJzendoorn, 2007). This research, along with the study discussed above and other recent work, highlights the concept of differential susceptibility discussed in Chapter 10 (page 409). That is, it suggests that certain genes result in children’s being differentially susceptible to the quality of their rearing environment, such that those with the “reactive” genes benefit more from having a secure attachment (e.g., are better adjusted and more prosocial than their peers) but do more poorly if they have an insecure attachment (Bakermans-Kranenburg & van IJzendoorn, 2007, 2011; Kochanska, Philibert, & Barry, 2009). Although this theory needs more validation, it appears that infants’ genetic makeup affects the degree to which their rearing environment alters their adjustment and social functioning. Does Security of Attachment Have Long-Term Effects? The reason that developmentalists are so interested in children’s attachment status is that securely attached infants appear to grow up to be better adjusted and more socially skilled than do insecurely attached children. One explanation for this may be that children with a secure attachment are more likely to develop positive and constructive internal working models of attachment. (Recall that children’s work- ing models of attachment are believed to shape their adjustment and social behavior, their self-perceptions and sense of self, and their expectations about other people, and there is some direct evidence for this belief [e.g., S. C. Johnson & Chen, 2011; S. C. Johnson, Dweck, & Chen, 2007].) In addition, children who experience the sensitive, supportive parenting that is associated with secure attachment are likely to learn that it is acceptable to express emotions in an appropriate way and that emotional com- munication with others is important (Cassidy, 1994; Riva Crugnola et al., 2011; Kerns et al., 2007). In contrast, insecure/avoidant children, whose parents tend to be nonre- sponsive to their signals of need and distress, are likely to learn to inhibit emotional expressiveness and to not seek comfort from other people (Bridges & Grolnick, 1995). Consistent with these patterns, children who were securely attached in infancy or early childhood later seem to have closer, more harmonious relationships with peers than do children who were insecurely attached (McElwain, Booth-LaForce, & Wu, 2011). For example, they are somewhat more regulated, sociable, and socially competent with peers (Lucas-Thompson & Clarke-Stewart, 2007; Panfile & Laible, 2012; Vondra et al., 2001). Correspondingly, they are less anxious, de- pressed, or socially withdrawn (Brumariu & Kerns, 2010)—especially compared with children who had insecure/resistant attachments (Groh et al., 2012)—as 438 n cHapTer 11 ATTACHMENT TO OTHERs AND DEVELOPMENT OF sELF well as less aggressive and delinquent (Fearon et al., 2010; Groh et al., 2012; Hoeve et al., 2012; NICHD Early Child Care Research Network, 2006). They are also bet- ter able to understand others’ emotions (Steele, Steele, & Croft, 2008; R. A. Thompson, 2008) and display more helping, sharing, and concern for peers (N. Eisenberg, Fabes, & Spinrad, 2006; Kestenbaum, Farber, & Sroufe, 1989; Panfile & Laible, 2012). Securely attached chil- dren are also more likely to report positive emotion and to exhibit normal rather than abnormal patterns of re- activity to stress (Bernard & Dozier, 2010; Borelli et al., 2010; Luijk et al., 2010). Finally, secure attachment in infancy even predicts positive peer and romantic relation- ships and emotional health in adolescence (E. A. Carlson, Sroufe, & Egeland, 2004; Collins et al., 1997) and early adulthood (Englund et al., 2011). Although there are only a few studies in which infants’ attachments to both parents were assessed, it appears that children may be most at risk if they have insecure attachments to both their mother and their father. In a study in which attachment was assessed at 15 months of age, children with insecure attachments to both parents were especially prone to prob- lem behaviors such as aggression and defiance in elementary school. Having either one secure attachment or secure attachments with both parents was associated with low levels of problem behaviors (Kochanska & Kim, 2013). However, it is not clear yet if having one secure attachment buffers against other types of negative outcomes, such as internalizing problems (e.g., anxiety, depression) or problems in interpersonal relations. Clearly, then, children’s security of attachment is related to their later psycholog- ical, social, and cognitive functioning. However, experts disagree on the meaning of this relationship. As noted, some theorists believe that early security of attachment has important effects on later development because it provides enduring work- ing models of positive relationships (Bowlby, 1973; Fraley, 2002; Sroufe, Egeland, & Kreutzer, 1990). This view implies that the effects of early attachment remain stable over time. Other theorists believe that early security of attachment predicts later development primarily to the degree that the child’s environment—includ- ing the quality of parent–child interactions—does not change (M. E. Lamb et al., 1985). In other words, early security of attachment predicts children’s functioning at an older age because “good” parents tend to remain good parents and “bad” par- ents tend to remain bad parents. Empirical findings support both perspectives to some degree. One study reported that even if children functioned poorly during the preschool years, those who had a secure attachment and adapted well during infancy and toddlerhood were more socially and emotionally competent in middle childhood than were their peers who had been insecurely attached (Sroufe et al., 1990). This suggests that a child’s early attachment has some effects over time. However, although there is often considerable stability in attachment security (Fraley, 2002; C. E. Hamilton, 2000), there is also evidence that children’s security of attachment can change somewhat as their environment changes—for example, with the onset or termination of stress and conflict in the home (Frosch, Mangelsdorf, & McHale, 2000; M. Lewis, Feiring, & Rosenthal, 2000; Moss et al., 2004) or a pronounced Toddlers who were securely attached as infants are more likely to engage in prosocial behavior, such as trying to comfort someone who is sad, than are those who were inse- curely attached as infants. M A R Y K AT E D E N N Y / P H O T O E D IT C O N C E P T I O N s O F T H E s E L F n 439 shift in the mother’s typical behavior with the child (L. M. Forbes et al., 2007) or in her sensitivity (Beijersbergen et al., 2012). In such cases, current parent–child interactions or parenting behaviors predict the child’s social and emotional com- petence at that age better than measures of attachment taken at younger ages (R. A. Thompson, 1998; Youngblade & Belsky, 1992). Indeed, children’s development can be predicted better from the combination of both their early attachment sta- tus and the quality of subsequent parenting (e.g., maternal sensitivity at an older age) than from either factor alone (Belsky & Fearon, 2002). Finally, it must be emphasized again that most of the research on attachment is correlational, so it is difficult to pin down causal relations. review: Evidence revealing the poor development of infants who are deprived of consistent, car- ing relationships with an adult led to the systematic study of infants’ early attachments. John Bowlby proposed that a secure attachment provides children with a secure base for exploration and contributes to a positive internal working model of relationships in general. According to attachment research, pioneered by Mary Ainsworth, children’s attachment rela- tionships with caregivers can be classified as secure, insecure/avoidant, insecure/resistant, and disorganized/disoriented. Children in these categories display similarities across cultures, although the percentage of children in different attachment groups sometimes varies across cultures or subcultures. Factors that appear to influence the security of attachment include parents’ sensitivity and responsiveness to their children’s needs and the parents’ own attachment status. Children’s security of attachment to their caregivers predicts the quality of their relationships with fam- ily members, which is likely to affect how children feel about and evaluate themselves. These relations may hold not only because the sensitivity of parenting in the early years of life has long-term effects but also because sensitive parents usually continue to provide effective parenting, whereas less sensitive parents continue to interact with the children in ways that undermine children’s optimal development. Conceptions of the Self As we have noted, children’s security of attachment to caregivers affects their feel- ings about themselves, especially in regard to their relationships with other people. Thus, it is not surprising that children’s attachment experiences early in life likely color their early sense of self, which emerges in infancy and carries over into child- hood (R. A. Thompson, 2008). However, the development of a sense of self is an ongoing, very complex process that involves much more than early-childhood attachments and notions of the self. When we speak of the self, we are referring to a conceptual system made up of one’s thoughts and attitudes about oneself. This conceptual system can include thoughts about one’s own physical being (e.g., body, possessions), social character- istics (e.g., relationships, personality, social roles), and “spiritual” or internal charac- teristics (e.g., thoughts and psychological functioning). It also may include notions about how the self changes or remains the same over time, beliefs about one’s own role in shaping these processes, and even reflections on one’s own consciousness of selfhood (Damon & Hart, 1988). The development of the self is important because individuals’ self-conceptions, including the ways they view and feel about them- selves, appear to influence their overall feelings of well-being and competence. self n a conceptual system made up of one’s thoughts and attitudes about oneself 440 n cHapTer 11 ATTACHMENT TO OTHERs AND DEVELOPMENT OF sELF The Development of Conceptions of Self Children’s sense of self changes in fairly dramatic ways across infancy, childhood, and adolescence. It continues to develop into adulthood, becoming more complex as the individual’s emotional and cognitive development deepens. The Self in Infancy There is compelling evidence that infants have a rudimentary sense of self in the first months of life. As noted in Chapters 5 and 10, by 2 to 4 months of age, infants have a sense of their ability to control objects outside themselves, as is clear both from their enthusiasm when they can make a mobile move by pulling a string attached to their arm and from their anger when their efforts no longer have an effect. They also seem to have some understanding of their own bodily move- ments. For instance, when viewing live video images of their own leg movements, 3- to 5-month-old infants looked lon- ger and moved their legs more when the video showed their leg movements from a perspective other than their own (e.g., when the right and left legs in the video image appeared to move in opposition to the leg movements the infants were per- forming) than when the video image showed leg movements as the infants themselves saw them (Rochat & Morgan, 1995). Perhaps their longer looking reflected their surprise at, or interest in, seeing the reversal of their leg movements (Rochat & Striano, 2002). A sense of self becomes much more distinct at about 8 months of age, when infants react with separation distress if parted from their mother, suggesting that they recognize that they and their mother are separate entities. Further indications that children view others as beings different from themselves are apparent by age 1. As discussed in Chapter 4 (page 159), around their 1st birthday, infants begin to show joint attention with respect to objects in the environment. For example, they will visually follow a caregiver’s pointing finger to find the object that the caregiver is calling atten- tion to, and then turn back to the caregiver to confirm that they are indeed look- ing at the intended object (Stern, 1985). They sometimes will also give objects to an adult in an apparent effort to engage the adult in their activities (M. J. West & Rheingold, 1978). Infants’ emerging recognition of the self becomes more directly apparent by 18 to 20 months of age, when many chil- dren can look into a mirror and realize that they are looking at themselves (Asendorpf, Warkentin, & Baudonnière, 1996; M. Lewis & Brooks-Gunn, 1979; Nielsen, Suddendorf, & Slaugh- ter, 2006). In studies that test this ability, an experimenter sur- reptitiously puts a dot of rouge on a child’s face, places the child in front of a mirror, and then asks the child who the person with the red spot is, or tells the child to clean the spot off the per- son in the mirror. Children younger than 18 months old often respond by trying to touch the image in the mirror, or they do nothing. By about the age of 18 months, however, many chil- dren touch the rouge on their own face, so it is assumed that they realize that the mirror image is a self-reflection. even young infants seem to experience a sense of mastery and control when they can make a mobile do their bidding by moving their arm. IN FA N T L E A R N IN G L A B O R AT O R Y, I N s T IT U T E F O R T H E s T U D Y O F C H IL D D E V E LO P M E N T, R O B E R T W O O D J O H N s O N M E D IC A L s C H O O L, M IC H A E L LE W Is , P H .D ., D IR E C T O R In this photo from the original research of Lewis and Brooks-Gunn, the girl recognizes that the child in the mirror with a spot on her cheek is herself. D R . M IC H A E L LE W Is , IN s T IT U T E F O R T H E s T U D Y O F C H IL D D E V E LO P M E N T, R O B E R T W O O D J O H N s O N M E D IC A L s C H O O L, U N IV E R s IT Y O F M E D IC IN E A N D D E N T Is T R Y O F N E W J E R s E Y, E A s T B R U N s W IC K , N .J . C O N C E P T I O N s O F T H E s E L F n 441 By age 2, many children can recognize themselves in photographs. In one study, 63% of a group of 20- to 25-month-olds picked themselves out when presented with pictures of themselves and two same-sex, same-age children. By approxi- mately age 30 months, 97% of the children immediately picked their own photo- graph (Bullock & Lütkenhaus, 1990). During their third year, children’s self-awareness becomes quite clear in other ways as well. As you saw in Chapter 10 (pages 392–393), 2-year-olds exhibit embarrassment and shame—emotions that obviously require a sense of self (M. Lewis, 1995, 1998). The strength of 2-year-olds’ awareness of self is even more evi- dent in their notorious self-assertion, which has led to the period between ages 2 and 3 being called the “terrible twos.” During this time, children often try to determine their activities and goals independent of, and often in direct opposition to, what their parents (and other adults) want them to do (Bullock & Lütkenhaus, 1990). Two-year-olds’ self-awareness is also evident in, and is enhanced by, their use of language. They can, for example, use pronouns to refer to themselves (“me,” “mine”) and can label themselves by name (e.g., “Daddy take Julia’s book”) (E. Bates, 1990). Young children can also use language to store in memory their own experiences and behavior, giving them access to information about themselves and their past. Thus, language makes it possible for children to construct a narrative of their own “life story” and develop a more enduring picture of the self (Harter, 2012; R. A. Thompson, 2006). Parents contribute to the child’s expanding self-image by providing descriptive information about the child (“You’re such a big boy”), evaluative descriptions of the child (“You’re so smart”), and information about the degree to which the child has met rules and standards (“Good girls don’t hit their baby sisters”). As noted in Chapter 4 (page 160), parents also collaborate in children’s construction of auto- biographical memory by reminding them of their past experiences (Snow, 1990). The Self in Childhood As children progress through childhood, their conception of themselves becomes increasingly complex and encompassing. This developmental pattern in self- understanding has been vividly illustrated by Susan Harter, a leading researcher on children’s emerging sense of self. Combining statements made by a wide array of children in a number of empirical studies, Harter has constructed composite exam- ples of children’s typical self-descriptive statements at different ages. The following is a composite example of how 3- to 4-year-olds describe themselves: I’m three years old and I live in a big house with my mother and father and my brother, Jason, and my sister, Lisa. I have blue eyes and a kitty that is orange and a television in my room. I know all of my ABC’s, listen: A, B, C, D, E, F, G, H, J, L, K, O, M, P, Q, X, Z. I can run real fast. I like pizza, and I have a nice teacher at pre- school. I can count up to 10, want to hear me? I love my dog Skipper. I can climb to the top of the jungle gym—I’m not scared! I’m never scared! I’m always happy. . . . I’m really strong. I can lift this chair, watch me! (Harter, 1999, p. 37) As this composite self-description demonstrates, at age 3 to 4, children under- stand themselves in terms of concrete, observable characteristics related to physi- cal attributes (“I have blue eyes”), physical activities and abilities (“I can run real fast”), social relationships (“my brother, Jason, and my sister, Lisa”), and psycho- logical traits (“I’m always happy”) (Damon & Hart, 1988; Harter, 1999). Their focus on observable features is further reflected by the fact that the prototypical 442 n cHapTer 11 ATTACHMENT TO OTHERs AND DEVELOPMENT OF sELF 3-year-old in the example bragged about particular skills such as running fast and did not make generalizations about his/her overall ability as an athlete. Even when the child made a general statement about himself/herself (“I’m really strong”), this statement was closely tied to actual behavior (lifting a chair). Young children also describe themselves in terms of their preferences (“I love my dog Skipper”) and possessions (“I have . . . a kitty . . . and a television”). The composite example reflects another characteristic typical of children’s self- concept during the preschool years: their self-evaluations are unrealistically posi- tive (Trzesniewski, Kinal, & Donnellan, 2010). Young children seem to think that they are really like what they want to be (Harter & Pike, 1984; Stipek, Roberts, & Sanborn, 1984). For example, the child in the composite self-description claimed mastery of the ABCs but clearly lacked it. Maintaining positive illusions about themselves is relatively easy for young children because they usually do not con- sider their own prior successes and failures when assessing their abilities. Even if they have failed badly at a task several times, they are likely to believe that they will succeed on the next try (Ruble et al., 1992). Children begin to refine their conceptions of self in elementary school, in part because they increasingly engage in social comparison, comparing themselves with others in terms of their characteristics, behaviors, and possessions (“He is big- ger than me”). At the same time, they increasingly pay attention to discrepancies between their own and others’ performance on tasks (“She got an A on the test and I only got a C”) (Chayer & Bouffard, 2010; Frey & Ruble, 1985). By middle to late elementary school, children’s conceptions of self have begun to become integrated and more broadly encompassing, as is illustrated by the following composite self- description that would be typical of a child between the ages of 8 and 11: I’m pretty popular, at least with the girls. That’s because I’m nice to people and help- ful and can keep secrets. Mostly I am nice to my friends, although if I get in a bad mood I sometimes say something that can be a little mean. . . . At school, I’m feel- ing pretty smart in certain subjects like Language Arts and Social Studies. . . . But I’m feeling pretty dumb in Math and Science, especially when I see how well a lot of the other kids are doing. Even though I’m not doing well in those subjects, I still like myself as a person, because Math and Science just aren’t that important to me. How I look and how popular I am are more important. I also like myself because I know my parents like me and so do other kids. That helps you like yourself. (Harter, 1999, p. 48) The developmental changes in older children’s con- ceptions of self reflect cognitive advances in their abil- ity to use higher-order concepts that integrate more specific behavioral features of the self. For example, the child in the preceding self-description was able to relate being “popular” to several behaviors, such as being “nice to others” and being able to “keep secrets.” In addition, older children can coordinate opposing self- representations (“smart” and “dumb”) that, at a younger age, they would have considered mutually ex- clusive (Harter, 1999, 2012; Marsh, Craven, & Debus, 1998). The newfound cognitive capacity to form higher-order conceptions of the self allows older chil- dren to construct more global views of themselves and to evaluate themselves as a person overall. These abili- ties result in a more balanced and realistic assessment In describing themselves, young children often make reference to their preferences and possessions such as a family pet. P U R E s T O C K / T H IN K s T O C K / G E T T Y I M A G E s In middle childhood, children start to refine their sense of self by comparing their own attributes and behavior with those of peers. This process of social comparison involves a variety of areas, ranging from physical abili- ties and academic achievement to material well-being. R A D IU s I M A G E s / A LA M Y C O N C E P T I O N s O F T H E s E L F n 443 of the self, although they also can result in feelings of inferiority and helplessness (see the discussion of achievement motivation in Chapter 9, pages 359–360). The preceding self-description also reflects the fact that schoolchildren’s self- concepts are increasingly based on others’ evaluations of them, especially those of their peers. Consequently, their self-descriptions often contain a pronounced social element and focus on characteristics that may influence their place in their social networks, as reflected in the following interview: WHAT ARE YOU LIKE? I am friendly. WHY IS THAT IMPORTANT? Other kids won’t like you if you aren’t. (Damon & Hart, 1988, p. 60) Because older school-aged children’s conceptions of self are strongly influenced by the opinions of others, children at this age are vulnerable to low self-esteem if others view them negatively or as less competent than their peers (Harter, 2006). The Self in Adolescence Children’s conceptions of self change in fundamental ways across adolescence, due in part to the emergence of abstract thinking during this stage of life (see Chapter 4, pages 141–142). The ability to use this kind of thinking allows adolescents to conceive of themselves in terms of abstract characteristics that encompass a variety of concrete traits and behaviors. Consider the following composite self-description of a young adolescent, 11 to 13 years old: I’m an extrovert with my friends: I’m talkative, pretty rowdy, and funny. . . . All in all, around people I know pretty well I’m awesome, at least I think my friends think I am. I’m usually cheerful when I’m with my friends, happy and excited to be doing things with them. . . . With my parents . . . I feel sad as well as mad and also hopeless about ever pleasing them. . . . At school, I’m pretty intelligent. I know that because I’m smart when it comes to how I do in classes, I’m curious about learning new things, and I’m also creative when it comes to solving problems. My teacher says so. . . . I can be a real introvert around people I don’t know well—I’m shy, uncomfortable, and nervous. Sometimes I’m simply an airhead, I act really dumb and say things that are just plain stupid. . . . (Harter, 1999, p. 60) As is evident in this composite example, young people’s concern over their social competence and their social acceptance, especially by peers, intensifies in early ado- lescence (Damon & Hart, 1988). The example also illustrates young adolescents’ ability to arrive at higher-level, abstract self-descriptions such as “extrovert” based on personal traits such as “talkative,” “rowdy,” and “funny.” Particularly notable is the fact that adolescents can conceive of themselves in terms of a variety of selves, depending on the context. The adolescent in the com- posite, for instance, describes himself/herself as a somewhat different person with friends and with parents, as well as with familiar and unfamiliar people. In part, this may be because young adolescents tend to think about each of their abstract representations of the self separately from other abstractions and cannot integrate them (Higgins, 1991). Consequently, in terms of their overall sense of themselves, it does not overly concern young adolescents that the person they appear to be can vary according to the context (see Figure 11.1). According to David Elkind (1967), thinking about the self in early adolescence is characterized by a form of egocentrism called the personal fable, in which ado- lescents overly differentiate their feelings from those of others and come to regard themselves, and especially their feelings, as unique and special. They may believe that social comparison n the process of comparing aspects of one’s own psy- chological, behavioral, or physical func- tioning to that of others in order to evaluate oneself personal fable n a form of adolescent egocentrism that involves beliefs in the uniqueness of one’s own feelings and thoughts 444 n cHapTer 11 ATTACHMENT TO OTHERs AND DEVELOPMENT OF sELF only they can experience whatever misery or rapture or confusion they are currently feeling. This belief is typified in the adolescent assertions “But you don’t know how it feels” and “My parents don’t understand me, what do they know about what it’s like to be a teenager?” (Elkind, 1967; Harter, 1999, p. 76). The tendency to exhibit this type of egocentrism is often still evident in late adolescence and may even increase in boys (P. D. Schwartz, Maynard, & Uzelac, 2008). The kind of egocentrism that underlies adolescents’ personal fables also causes many adolescents to be preoccupied with what others think of them (Elkind, 1967; Harter, 1999; Rosenberg, 1979). This preoccupation is exhibited in what Elkind (1967) has labeled as the adolescent’s belief in an imaginary audience. According to Elkind, because adolescents are so concerned with their own appearance and behavior, they assume that everyone else is, too. Wherever they are, whatever they are doing, they think that all eyes are on them, scrutinizing their every blemish or social misstep. This dimension of adolescent egocentrism, like the personal fable, has been found to become stronger across adolescence for boys but not girls (P. D. Schwartz et al., 2008). In their middle teens, adolescents often begin to agonize over the contradic- tions in their behavior and characteristics. They tend to become introspective and concerned with the question “Who am I?” (Broughton, 1978). Their con- cern with this question is reflected in the following composite self-description of a 15-year-old: What am I like as a person? You’re probably not going to understand. I’m compli- cated! With my really close friends, I am very tolerant, I mean I’m understanding and caring. With a group of friends I’m rowdier. I’m also usually friendly and cheerful, but I can be pretty obnoxious and intolerant if I don’t like how they’re acting. . . . I really don’t understand how I can switch so fast from being cheerful with my friends, then Grade level M ea n n u m b er o f op p os it es 1197 4.5 4.0 3.5 3.0 2.5 Grade level P er ce n t of o p p os it es w h ic h a re i n c on fl ic t 1197 45 40 35 30 25 20 Grade level P er ce n t of s u b je ct s re p or ti n g th at a t le as t on e op p os it e ca u se s co n fl ic t 1197 80 70 60 50 40 30 20 Grade level P er ce n t of s u b je ct s re p or ti n g th at o p p os it es m ak e th em f ee l co n fu se d o r m ix ed u p 1197 80 70 60 50 40 30 20 FIGURE 11.1 Developmental differences in adolescents’ perceptions of opposing and conflicting self-attributes When asked about their characteristics, 7th-graders were much less likely than older adolescents to report contradictions in their characteristics. Older adolescents, especially 9th-graders, reported that such contradictions caused them to feel internal conflict such as con- fusion or negative emotion. (adapted from Harter & Monsour, 1992) imaginary audience n the belief, stemming from adolescent egocentrism, that everyone else is focused on the ado- lescent’s appearance and behavior C O N C E P T I O N s O F T H E s E L F n 445 coming home and feeling anxious, and then getting frustrated and sarcastic with my parents. Which one is the real me? (Quoted in Harter, 1999, p. 67) Although adolescents in their middle teens are better than younger adolescents at identifying contradictions in themselves (see Figure 11.2) and often feel conflicted about these inconsistencies, most still do not have the cognitive skills needed to integrate their recognition of these contradictions into a coherent conception of self. As a consequence, adolescents of this age often feel confused and concerned about who they really are. As one teen put it, “It’s not right, it should all fit together in one piece!” (Harter, 1999, p. 71; Harter et al., 1998). In late adolescence and early adulthood, the individual’s conception of self be- comes both more integrated and less determined by what others think. Both of these shifts are captured by Harter’s composite representation of a high school senior: I’d like to be an ethical person who treats other people fairly. That’s the kind of lawyer I’d like to be, too. I don’t always live up to that standard; that is, sometimes I do some- thing that doesn’t feel that ethical. When that happens I get a little depressed because I don’t like myself as a person. But I tell myself that it’s natural to make mistakes, so I don’t really question the fact that deep down inside, the real me is a moral person. Basically, I like who I am. . . . Being athletic isn’t that high on my own list of what is important, even though it is for a lot of the kids in our school. But I don’t really care what they think anymore. I used to, but now what I think is what counts. After all, I have to live with myself as a person and to respect that person, which I do now, more than a few years ago. (Quoted in Harter, 1999, p. 78) As in the case of this prototypical senior, older adolescents’ conceptions of self frequently reflect internalized personal values, beliefs, and stan- dards. Many of these were instilled by others in the child’s life but are now accepted and gener- ated by adolescents as their own. Thus, older ado- lescents place less emphasis on what other people think than they did at younger ages and are more concerned with meeting their own standards and with their future self—what they are becoming or are going to be (Harter, 1999, 2012; Higgins, 1991). Older adolescents are also more likely to have the cognitive capacity to integrate opposites or contradictions in the self that occur in different contexts or at different times (Higgins, 1991). They may explain contradictory characteristics in terms of the need to be flexible, and may view variations in their behavior with different people as “adaptive” because one cannot act the same with everyone. Similarly, they may integrate changes in emotion under the characteristic “moody.” Moreover, they are likely to view their contradictions and inconsistencies as a normal part of being human, which likely reduces feelings of conflict and upset. Whether older adolescents are able to successfully integrate contradictions in themselves likely depends not only on their own cognitive capacities but also on the help they receive from parents, teachers, and others in understanding the complexity IN TH E CL AS SR OO M WITH MY MOTHER WI TH M Y FAT HE R responsible What I Am Like With Different People close stubborn honest short tempered open at ease OPPOSITES CONFLICTS rowdy admiring respectful not open defensive distant serious talkative cheerful assertive outgoing sarcastic self-conscious good listener shy not always me nervous sensitive comfortable caring understanding moody quiet myself serious withdrawn cooperative frustrated respectful WITH MY BEST FRIEND WITH A ROMANTIC INTEREST WITH A GROUP OF FRIENDS FIGURE 11.2 The multiple selves of a prototypical 15-year-old girl The girl rep- resented by this diagram viewed herself as being different in different contexts or with different people. For example, she described herself as open with her mother but not her father, and as quiet with her best friend but rowdy with a group of friends. (adapted from Harter, 1999) 446 n cHapTer 11 ATTACHMENT TO OTHERs AND DEVELOPMENT OF sELF of personalities. The support and tutelage of others in this regard allow adolescents to internalize values, beliefs, and standards that they feel committed to and to feel com- fortable with who they are (D. Hart & Fegley, 1995; Harter, 1999, 2012). Identity in Adolescence Clearly, the question “Who am I?” is a central and often dis- turbing one for many adolescents. It is also a question that, for many older adolescents, expands well beyond the issue of multiple selves and inconsistent behavior. As they begin to approach adulthood, adolescents must begin to develop a sense of personal identity that incorporates numerous aspects of self, including their values, their belief systems, their goals for the future, and, for some, their sexual identity. As noted in Chapter 9, Erik Erikson argued that the reso- lution of these many identity issues is the chief developmen- tal task in adolescence. He referred to the resolution of these issues as the crisis of identity versus identity confusion. In his view, the challenge is as follows: “From among all possible and imaginable relations, [the person] must make a series of ever-narrowing selections of personal, occupational, sexual, and ideological commitments” (1968, p. 245). Successful resolu- tion of this crisis results in identity achievement—that is, an integration of various aspects of the self into a coherent whole that is stable over time and across events. Erikson’s Theory of Identity Formation According to Erikson, adolescents who fail to attain identity achievement can experience one of several negative outcomes. One such outcome is identity con fusion, an incomplete and sometimes incoherent sense of self that may cause the adolescent to feel lost, isolated, and depressed. Erikson suggested that some form of identity confusion is very common in adolescence and that it generally lasts for a relatively short time, although, according to Erikson, it sometimes persists and turns into a more severe psychological disturbance. Feelings of self-worth develop partly from the child’s feelings of acceptance in the family. F R A N C Is C O C R U Z / s U P E R s T O C K During late adolescence, re-examination of one’s value system is common. Often the outcome is either renewed commitment to previously held beliefs or total rejection of them. R O B E R T W A LL Is / C O R B Is identity versus identity confusion n the psychosocial stage of development, described by Erikson, that occurs during adolescence. During this stage, the ado- lescent or young adult either develops an identity or experiences an incomplete and sometimes incoherent sense of self. identity achievement n an integra- tion of various aspects of the self into a coherent whole that is stable over time and across events identity confusion n an incomplete and sometimes incoherent sense of self that often occurs in Erikson’s stage of identity versus identity confusion C O N C E P T I O N s O F T H E s E L F n 447 Another negative outcome related to the struggle for identity can arise if ado- lescents commit themselves to an identity prematurely, that is, without adequately considering alternative possibilities. This identity choice is called identity fore­ closure. An example of this category might be a 17-year-old who quits school and goes to work in a dead-end job because he or she does not envision any other options, or a young adolescent who, never considering other available career tracks, decides to become a doctor simply because his or her parent is one. A different self-defeating outcome of the search for an identity is a negative identity, one that is chosen because it represents the opposite of what is valued by people around the adolescent. A typical example would be a minister’s child’s willfully engaging in blatant immoral behavior, or a professor’s child’s rebelliously dropping out of high school with no occupational goal in mind. For some adoles- cents, Erikson suggested, taking on a negative identity is a way of getting noticed by significant others when more conventional attempts have failed. Erikson (1968) argued that because of all the “possible and imaginable” role options that are available in modern society, attaining identity achievement is highly complex and difficult. In light of the negative consequences of failing to achieve a coherent identity, he proposed the importance of a psychosocial mora­ torium—a time-out period during which the adolescent is not expected to take on adult roles and is free to pursue activities that lead to self-discovery. During this period, adolescents can try out new looks, new ways of acting, new ideas about what they want to do for a living, and so forth. Although Erikson argued that this period of experimentation is important to adolescents’ finding the best identity for themselves, a moratorium of this sort is possible or acceptable only in some cultures. Even then, it is often a luxury reserved for the middle and upper classes (i.e., those can who afford the moratorium pro- vided by the college years). If adolescents must work full time to help support their families and themselves, many identity options will be closed to them because of limits on their time and schooling. In addition, in traditional societies where there are few role choices available, a moratorium is unheard of and unnecessary: children know from a very young age what their adult identity will be, and people generally live their lives in the same manner as their parents have. Research on Identity Formation Following up on Erikson’s depiction of identity formation, a number of research- ers looked for ways to measure the identity status of adolescents and to trace the outcome of the various statuses proposed by Erikson. The method most often used for this purpose was devised by James Marcia (1980). In this method, study partici- pants are interviewed to determine the extent of their exploration of, and commit- ment to, issues related to occupation, ideology (e.g., religion, politics), and sexual behavior. On the basis of their responses, they are classified into one of the follow- ing four categories of identity status: n Identity­diffusion status. The individual does not have firm commitments regarding the issues in question and is not making progress toward developing them. n Foreclosure status. The individual has not engaged in any identity experi- mentation and has established a vocational or ideological identity based on the choices or values of others. n Moratorium status. The individual is exploring various occupational and ideo logical choices and has not yet made a clear commitment to them. identity foreclosure n premature com- mitment to an identity without adequate consideration of other options negative identity n identity that stands in opposition to what is valued by people around the adolescent psychosocial moratorium n a time- out during which the adolescent is not expected to take on adult roles and can instead pursue activities that may lead to self-discovery identity-diffusion status n a category of identity status in which the individual does not have firm commitments and is not making progress toward them foreclosure status n a category of identity status in which the individual is not engaged in any identity experimenta- tion and has established a vocational or ideological identity based on the choices or values of others moratorium status n a category of identity status in which the individual is in the phase of experimentation with regard to occupational and ideological choices and has not yet made a clear commitment to them Trying out various “looks” can be an aspect of the self-discovery that occurs among many adolescents in some cultures. P Y M C A / A LA M Y 448 n cHapTer 11 ATTACHMENT TO OTHERs AND DEVELOPMENT OF sELF n Identity­achievement status. The individual has achieved a coherent and consolidated identity based on personal decisions regarding occupation, ide- ology, and the like. The individual believes that these decisions were made autonomously and is committed to them. More recently, researchers have delineated some additional distinc- tions in identity status. They propose, for example, that, during the moratorium, certain individuals explore possible commitments in two different ways. Some may explore them in breadth, trying out a vari- ety of candidate identities before choosing one (Luyckx, Goossens, & Soenens, 2006; Luyckx, Goossens et al., 2006). For example, a person might consider being a musician, artist, or historian. (This type of ex- ploration is similar to Marcia’s notion of moratorium.) Others may make an initial commitment and explore it in depth, through continu- ous monitoring of current commitments in order to make them more conscious (Meeus et al., 2010). Thus, they may try out various types of art (painting, sculpture) before committing to being an artist. Researchers using methods similar to Marcia’s have found that most young adolescents seem to be in identity diffusion or identity foreclosure and that the percentage of youth in moratorium status is highest at ages 17 to 19 (Nurmi, 2004; Waterman, 1999). In the course of adolescence and early adulthood, individuals generally prog- ress slowly toward identity achievement (Kroger et al., 2010; Meeus, 2011). The most typical sequences of change appear to be from diffu- sion → early foreclosure → achievement, or from diffusion → mora- torium → closure → achievement; few move in the opposite direction (Meeus, 2011). There is little evidence that many adolescents have the kind of sustained identity confusion that Erikson maintained could lead to severe psychological disturbance (Meeus, 2011). Researchers generally have found that, at least in modern Western societies, the identity status of adolescents and young adults is related to their adjustment, social behavior, and personality. Those who have made a commitment, whether through foreclosure or identity achievement, tend to be emotionally stable and high in self- esteem (Crocetti et al., 2008), low in depression and anxiety, and extroverted and agreeable (Luyckx et al., 2005; Luyckx et al., 2006; Meeus, 1996). Young adults who explore possible commitments more in depth than in breadth tend to be extroverted, agreeable, and conscientious (reliable, regulated), whereas those who explore more in breadth tend to be prone to negative emotionality but open to experience ( Dunkel & Anthis, 2001; Luyckx et al., 2006). Individuals who have made commitments through foreclosure tend to be low on substance use (Luyckx et al., 2005) and aggression ( Crocetti et al., 2008; Luyckx et al., 2008). In contrast, adolescents who are in morato- rium, especially when they are experimenting in breadth, seem to be relatively likely to take drugs or to have unprotected sex ( J. T. Hernandez & DiClemente, 1992; R. M. Jones, 1992; Luyckx, Goossens et al., 2006). Influences on Identity Formation A number of factors influence adolescents’ identity formation. One key factor is the approach parents take with their offspring. Adolescents who experience warmth and support from parents tend to have a more mature identity and less identity confusion (Meeus, 2011; S. J. Schwartz et al., 2009). In addition, parents tend to react with support when young college students explore in depth and make iden- tity commitments (Beyers & Goossens, 2008), and this support may reinforce their In some traditional cultures, adolescents have few role options and, consequently, know from a young age what their adult identity will be. JO H N W A R B U R T O N -L E E P H O T O G R A P H Y / A LA M Y identity-achievement status n a cat- egory of identity status in which, after a period of exploration, the individual has achieved a coherent and consolidated identity based on personal decisions regarding occupation, ideology, and the like. The individual believes that these decisions were made autonomously and is committed to them. E T H N I C I D E N T I T Y n 449 children's choices. Youths who are subject to parental psychological control tend to explore in breadth and are lower in making commitment to an identity (Luyckx et al., 2007). Adolescents are also more likely to explore identity options rather than go into foreclosure if they have at least one parent who encourages in them both a sense of connection with the parent and a striving for autonomy and individuality (Grotevant, 1998). Identity formation is also influenced by both the larger social context and the historical context (Bosma & Kunnen, 2001). As already noted, adolescents from poor communities may have fewer career options because of low-quality schooling, financial limitations, and a lack of career information and role models. Such limita- tions likely affect some aspects of these adolescents’ identity formation. The historical context plays a role in identity formation as well, because of the changes it brings about in identity options over time. Until a few decades ago, for instance, most adolescent girls focused their search for identity on the goal of marriage and family. Even in developed societies, few career opportunities were available to women. Today, women in many cultures are more likely to base their identity on both family and career. Thus, familial, individual, socioeconomic, his- torical, and cultural factors all contribute to identity development. review: Children’s self-conceptions change greatly with age, shifting from being very concrete—based on physical characteristics and overt behavior—to being based on internal qualities and the nature of one’s relationships with others. Young children tend to view themselves in uniformly positive ways and to overestimate their abilities. Older children are more likely to evaluate themselves on their general level of competence and to assess their own strengths and weak- nesses realistically. In late childhood, children increasingly incorporate others’ perceptions of themselves into their self-image, and, with age, their conceptions of self also become much more complex and integrated. Adolescents’ self-conceptions are more abstract than younger children’s and include the existence of different selves in different contexts. Young adolescents usually are not upset when they perceive discrepancies in their behavior and characteristics across contexts. However, according to Elkind, many young adolescents do develop a form of egocentrism that expresses itself as the “personal fable” and the critical “imaginary audience.” In mid- adolescence, teenagers often agonize over the discrepancies they see in themselves and tend to become concerned with the question “Who am I?” and with what others think of them. In late adolescence and early adulthood, concepts of the self become much more integrated and are more likely to include personal attributes that reflect internalized personal values, beliefs, and standards. According to Erikson, adolescence is the time of the crisis of identity versus identity con- fusion, in which the young person must form an identity by making a series of ever- narrowing selections of personal, occupational, sexual, and ideological commitments. Exploration of choices relevant to one’s identity, especially exploration in depth, appears to be a healthy option in Western cultures but may not be a viable one in some cultures and subcultures. Most youths eventually move toward identity achievement, some with more exploration than others; this process is usually slow, and youths are fairly stable in their identity status over time. How and when young people construct their identity are affected by a variety of influ- ences, ranging from personal and familial factors to cultural and historical ones. Ethnic Identity The development of identity can present special challenges for minority-group adolescents because it often involves complications related to ethnicity and/ or race. In certain contexts, a legitimate distinction can be drawn between the 450 n cHapTer 11 ATTACHMENT TO OTHERs AND DEVELOPMENT OF sELF concept of ethnicity (which refers to shared cultural traditions) (M. B. Spencer & Markstrom- Adams, 1990) and the concept of race (which refers to a shared biologi- cal ancestry). In the context of identity formation, however, the two concepts are, for practical purposes, quite similar. Thus, for the present discussion, we will use the term ethnic identity to refer to the degree to which an individual has a sense of belonging to an ethnic or racial group and associates his or her thinking, feelings, and behavior with membership in that ethnic or racial group (Rotheram & Phinney, 1987). Ethnic Identity in Childhood Children’s ethnic identity can be viewed as having five components (Bernal et al., 1993): TABLE 11.2 examples of components of ethnic Identity in preschool and the early School Years Ethnic-Identity Components Preschool Level Early School Level Ethnic knowledge Simple, global knowledge More complex and specific knowledge, including cultural traits Ethnic self-identification Empty labels: “I’m Mexican because my mother said so.” Meaningful labels: “I’m Mexican because my parents come from Mexico.” Ethnic constancy Don’t understand Understand permanence of their ethnicity Ethnic-role behaviors Engage in and describe behaviors; may not know why behaviors are ethnic Engage in more role behaviors; know more about their ethnic relevance Ethnic feelings and preferences Undeveloped; do as their families do Have feelings and preferences Source: Adapted from Bernal et al., 1993 n Ethnic knowledge. Children’s knowledge that their ethnic group has cer- tain distinguishing characteristics—behaviors, traits, values, customs, styles, and language—that set it apart from other groups. n Ethnic self-identification. Children’s categorization of themselves as members of their ethnic group. n Ethnic constancy. Children’s understanding that the distinguishing char- acteristics of their ethnic group do not change across time and place and that they themselves will always be a member of their ethnic group. n Ethnic-role behaviors. Children’s engagement in the behaviors that reflect the distinguishing characteristics of their ethnic group. n Ethnic feelings and preferences. Children’s feelings about belonging to their ethnic group and their preferences for the group’s members and the characteristics that distinguish the group. Ethnic identity develops gradually during childhood, although it does not develop for all ethnic-minority children. Preschool children do not really understand the significance of being a member of an ethnic group, although they may be able to label themselves as “Mexican,” “Native Amer- ican,” “African American,” or the like. Even if they engage in behaviors that characterize their ethnic group and have some simple knowledge about the group, they do not understand that ethnicity is a lasting feature of the self (Bernal et al., 1993) (see Table 11.2). Much of young children’s learning about their ethnic group takes place in the family. parents teach their children the specific practices associated with their group and can instill in them pride in their ethnic heritage. E D U C AT IO N I M A G E s G R O U P / G E T T Y I M A G E s ethnic identity n individuals’ sense of belonging to an ethnic or racial group, including the degree to which they asso- ciate their thinking, perceptions, feelings, and behavior with membership in that group E T H N I C I D E N T I T Y n 451 By the early school years, ethnic-minority children know the common char- acteristics of their ethnic group, start to have feelings about being members of the group, and may have begun to form ethnically based preferences regarding foods, traditional holiday activities, language use, and so forth (Ocampo, Bernal, & Knight, 1993). Children tend to identify themselves according to their ethnic group between the ages of 5 and 8 and shortly thereafter begin to understand that their race or ethnicity is an unchanging feature of themselves (Bernal et al., 1990; Ocampo, Knight, & Bernal, 1997). By late elementary school, minority children in the United States often have a very positive view of their ethnic group (D. Hughes, Way, & Rivas-Drake, 2011). The family and the larger social environment play a major role in the develop- ment of children’s ethnic identity. Parents and other family members and adults can be instrumental in teaching their children about the strengths and unique fea- tures of their ethnic culture and instilling them with ethnic pride (A. B. Evans et al., 2012; Hughes et al., 2006; Vera & Quintana, 2004). Such instruction can be especially important for the development of a positive ethnic identity when the child’s racial or ethnic group is the object of prejudice and discrimination in the larger society (Gaylord-Harden, Burrows, & Cunningham, 2012; M. B. Spencer & Markstrom- Adams, 1990). Ethnic Identity in Adolescence The issue of ethnic or racial identity often becomes more central in adolescence, as young people try to forge their overall identity (S. E. French et al., 2006). Minority-group members in particular may be faced with difficult and painful decisions as they try to decide the degree to which they will adopt the values of their ethnic group or those of the dominant culture (Phinney, 1993; M. B. Spencer & Markstrom-Adams, 1990). One difficulty for ethnic-minority adolescents is that they are more likely than they were at younger ages to be aware of discrimination against their group and consequently may feel ambivalent about the group and their own ethnic status (M. L. Greene, Way, & Pahl, 2006; Seaton et al., 2008; Szalacha et al., 2003). Eth- nic-minority children may also be faced with basic conflicts between the values of their ethnic group and those of the dominant culture (Parke & Buriel, 2006; Qin, 2009). For example, many ethnic groups place a premium on family obligation, in- cluding values and behaviors related to children’s assisting, supporting, and respect- ing members of the nuclear and extended family. Thus, adolescents in traditional Mexican American families, for instance, may be expected to spend after-school time helping take care of elderly or young family members or earning money for the family. At the same time, the majority culture may be urging them to partici- pate in school-related activities—such as sports, clubs, or study groups—that can lead to expanded opportunities. Extending the work of Erikson, Jean Phinney (Phinney & Kohatsu, 1997) has identified three phases of ethnic-identity development that minority youth often experience: n Ethnic-identity diffusion/foreclosure. In this phase, many ethnic-minority ado- lescents have not examined their ethnicity and are not particularly interested in it. Some others have internalized the majority society’s negative views of their ethnic group. n Ethnic-identity search/moratorium. Minority youth in this phase develop an interest in learning about their ethnic or racial culture and begin to consider 452 n cHapTer 11 ATTACHMENT TO OTHERs AND DEVELOPMENT OF sELF the effects that their ethnicity may have on their life in the present and future. In some cases, this exploration eventually leads to the third phase, ethnic- identity achievement (K. A. Whitehead et al., 2009). n Ethnic-identity achievement. This phase is characterized by a more conscious awareness of, and commitment to, one’s ethnic group and ethnic identity (M. B. Spencer & Markstrom-Adams, 1990). Research suggests that higher levels of ethnic identity are generally associated with high self-esteem, well-being, and low levels of emotional and behavior prob- lems (Berkel et al., 2009; M. D. Jones & Galliher, 2007; Kiang et al., 2006; Neblett, Rivas-Drake, & Umaña-Taylor, 2012). For example, advances in African American adolescents’ racial identity have been associated with a decline in their symptoms of depression (Mandara et al., 2009), and adolescents with a positive ethnic identity appear to be buffered from the negative effects of discrimination (Gaylord-Harden et al., 2012; Tynes et al., 2012). The benefits of high ethnic identification appear to hold more consistently for African American and Latino youth than for Asian American youth (Umaña-Taylor, 2011). Most ethnic-minority adolescents either have stable ethnic identities or pro- gress through the sequence of ethnic-identity development outlined above (Meeus, 2011; Umaña-Taylor, Gonzales-Backen, & Guimond, 2009). The exploration of ethnic identity does not always follow this pattern, however. For some ethnic- minority adolescents, an identity search leads to an exploration of majority identities and a lessening of commitment to the ethnic group. Establish- ing a clear ethnic identification may be more difficult and less consistent for some adolescents, such as multiethnic youth, who could develop identifications with more than one ethnic or racial group (Marks et al., 2011; Nishina et al., 2010). However, when ethnic-minority parents actively socialize their children into their ethnic culture through teaching about the culture and instilling pride, children tend to have a more positive ethnic identity (Neblett et al., 2012; Umaña-Taylor, Bhanot, & Shin, 2006; Umaña-Taylor & Guimond, 2010) and are less susceptible engaging in activities that promote the wel- fare of others in their ethnic or racial group may contribute to adolescents’ having a positive sense of ethnic identity. The ado- lescents shown here are members of a youth-development group that carries out community projects ranging from cleaning parks and painting neighborhood murals to tending community gardens and working in a food pantry for the needy. FR E s H Y O U T H I N IT IA T IV E s s E x U A L I D E N T I T Y O R O R I E N T A T I O N n 453 to the negative effects of discrimination (Harris-Britt et al., 2007; Neblett et al., 2008; M. -T. Wang & Huguley, 2012). In some cases, ethnic-minority youth develop a bicultural identity that includes a comfortable identification with both the majority culture and their own eth- nic culture. Although trying to straddle two cultures can be stressful, it is not always so, and for some minority youths it can provide certain benefits, such as positive perceptions of opportunities in the majority society (Fuligni, Yip, & Tseng, 2002; Kiang & Harter, 2008; Kiang, Yip, & Fuligni, 2008; LaFromboise, Coleman, & Gerton, 1993). However, for adolescents in some traditional cultures (e.g., Canadian First Nations), a bicultural identity can be associated with lower levels of some strengths that are part of successful identity development, such as certain traditional values, as well as fidelity (loyalty and commitment) and wisdom (Gfellner & Armstrong, 2012). review: The development of identity may be especially complicated for many ethnic-minority youth because it involves incorporating ideas and feelings about their ethnicity and/or race. The development of an ethnic identity begins in childhood and involves acquiring knowledge about one’s ethnic group, identifying oneself as a member of that group, developing an understanding of ethnic constancy, engaging in ethnic-role behaviors, and developing feel- ings and preferences with regard to belonging to one’s ethnic group. Family and community influence these aspects of development. The achievement of an identity during adolescence can be difficult and painful for minor- ity youth due to their awareness of prejudice against their group. Possible clashes between the values and goals of the group and those of the majority culture can further complicate the process. In adolescence, some minority youth start to actively explore the meaning of their ethnicity and its role in their identity. As a result of this exploration, some adolescents embrace their ethnicity; others gravitate toward the majority culture; and still others identify with both cultures. Sexual Identity or Orientation In childhood and especially adolescence, an individual’s identity includes his or her sexual orientation—that is, a person’s preference in regard to erotic feelings toward males or females. The majority of youth are attracted to individuals of the other sex; a sizable minority is not. Dealing with new feelings of sexuality can be a difficult experience for any adolescent, but the issue of establishing a sexual identity is much harder for some adolescents than for others. The Origins of Youths’ Sexual Identity Puberty, during which there are large rises in gonadal hormones (Buchanan, Eccles, & Becker, 1992; C. T. Halpern, Udry, & Suchindran, 1997), is the most likely time for youth to begin experiencing feelings of sexual attraction to others. Most current theorists believe that whether those feelings are inspired by members of the other sex or one’s own is based primarily on biological factors, although the environment may also be a contributing factor (Savin-Williams & Cohen, 2004). Twin and adoption studies, as well as DNA studies, indicate that a person’s sexual orientation is at least partly hereditary: identical twins, for example, are more likely to exhibit similar sexual orientations than are fraternal twins ( J. Bailey & Pillard, 1991; J. Bailey et al., 1993; Hamer et al., 1993). sexual orientation n a person’s pref- erence in regard to males or females as objects of erotic feelings 454 n cHapTer 11 ATTACHMENT TO OTHERs AND DEVELOPMENT OF sELF Sexual Identity in Sexual-Minority Youth For the majority of youth everywhere, the question of personal sexual orientation never arises, at least at a conscious level. They feel themselves to be unquestioningly heterosexual. For a minority of youth, however, the question of personal sexual identity is a vital one that, initially at least, is often confusing and painful. These are the sexual­minority youth, who experience same-sex attractions. It is difficult to know precisely how many youths are in this category. Although current estimates indicate that only 2% to 4% of high school students in the United States identify themselves as gay, lesbian, or bisexual (Rotheram-Borus & Langabeer, 2001; Savin-Williams & Ream, 2007), the number of youths with same-sex attrac- tions is considerably larger because many sexual-minority youth do not identify themselves as such until early adulthood or later (Savin-Williams & Ream, 2007). It is true that, growing up, sexual-minority youth often feel “different” (a difference pos- sibly reflected in their frequently being labeled sissies or tomboys) (Savin- Williams & Cohen, 2007), and some even display cross-gender behavior—for example, in regard to preferences for toys, clothes, or leisure activities—from a relatively early age (Drummond et al., 2008). However, it sometimes takes them a long time to recog- nize that they are lesbian, gay, or bisexual. Another complicating fact is that, especially for females, there is considerable insta- bility in adolescents’ and young adults’ reports of same-sex attraction or sexual behav- ior (Savin-Williams & Ream, 2007). By college age, for example, a notable number of young women identify themselves as “mostly straight”—that is, mostly heterosexual but somewhat attracted to females (E. M. Thompson & Morgan, 2008). One longi- tudinal study that followed 79 lesbian, bisexual, and unlabeled (those with some same-sex involvement who were unwilling to attach a label to their sexuality) women aged 18 to 25 found that, over a 10-year period, two- thirds changed the identity labels they had claimed at the beginning of the study and one-third changed labels two or more times (L. M. Diamond, 2008). Overall, females are more likely to describe themselves as bisexual or “mostly heterosexual” than are males (Saewyc, 2011). Male youth who have engaged in same-sex sexual experiences show an increasing preference for males from adolescence to early adulthood (Smiler et al., 2011). In most ways, sexual-minority children and adolescents are develop- mentally indistinguishable from their heterosexual peers: they deal with many of the same family and identity issues in adolescence and generally function just as well. However, they do face some special challenges. Be- cause being gay, lesbian, or bisexual is viewed negatively by many members of society, it is often difficult for sexual-minority youth to recognize or ac- cept their own sexual preferences. It is usually even more difficult for them to reveal their sexual identity to others—that is, to “come out.” How- ever, with the media’s increasing attention to, and positive portrayals of, sexual-minority people, as well as increasing legal and cultural acceptance of sexual minorities, more sexual-minority youths in the United States are coming out today than did any previous cohort (Savin-Williams, 2005). The Process of Coming Out In many cases, the coming-out process for sexual-minority youth involves several developmental phases, some of which occur in varying sequences. It begins with the first recognition—an initial realization that one is somewhat different from others, accompanied by feelings of alienation from oneself Sexual-minority youth deal with many of the same family and identity issues as do other adolescents, and they are generally equally as adjusted as other teens. However, they face special challenges if their peers and family do not accept their sexual identity. In what may be a sign of changing attitudes, these two Minnesota high school seniors, who were among the students elected to their school's ceremonial "royal court," filed a civil suit to gain the right to walk together as a couple in the royal court's opening pro- cession. Their legal victory and their appear- ance together in the procession brought cheers from many of their schoolmates. A P P H O T O /J IM M O N E sexual-minority youth n young people who experience same-sex attractions s E x U A L I D E N T I T Y O R O R I E N T A T I O N n 455 and others. At this point, there generally is some awareness that same-sex attractions may be the relevant issue, but the individual does not reveal this to others. A number of sexual-minority youth have some awareness of their sexual attractions by middle child- hood (Savin- Williams & Diamond, 2000; see Table 11.3). As one gay male reported: Maybe it was the third grade and there was an ad in the paper about an all-male cast for a movie. This confused me but fascinated—intrigued—me, so I asked the librarian and she looked all flustered, even mortified, and mumbled that I ought to ask my parents. (Quoted in Savin-Williams, 1998a, p. 24) However, there is great variability in the age at which same-sex attractions are first noticed. In one recent study of a large sample of gay, lesbian, and bisexual adults, researchers differentiated three age groups for initial recognition of same- sex attraction (Calzo et al., 2011). The largest group, labeled the early-onset group (75% of the sample), reported, on average, that their first same-sex attraction was at about 12 to 14 years of age, with roughly 30% of this group reporting initial same- sex attractions at 7 or 8 years of age. The second largest group, labeled the middle group (19% of the sample), reported that their first same-sex attraction occurred in late adolescence. The third group, labeled the late-onset group (6% of the sample), reported same-sex attractions beginning at an average age of 29 years for men and 34 years for women. Women were much more likely than men to be in the middle and late-onset groups, and within each of these onset groups, women reported somewhat later onset of same-sex attractions. In all three groups, the initial same- sex attractions reported by bisexuals occurred about 1 or 2 years later than those reported by gay and lesbian individuals. The length of time between recognition of same-sex attractions and self- identification as gay, lesbian, or bisexual varies. For the early-onset group in the study just mentioned, the identification typically occurred about 4 years after the initial recognition of same-sex attractions; for the other two groups, it occurred between 5 and 8 years after initial recognition (see Table 11.3). TABLE 11.3 ages of Identity Milestones for Gay/Bisexual Male Youth in Savin-Williams’s Study (all are gay youth who have acknowledged their sexual-minority identity) Event Mean Age in Years Age Range Percent Who Had Not Experienced the Event Awareness of same-sex attractions 8 3–17 0% Knew meaning of homosexuality 10 4–19 0% Applied the term homosexual to own attractions 13 5–20 0% First gay sex 14 5–24 7% First heterosexual sex 15 5–22 48% Recognized self as gay/bisexual 17 8–24 0% First disclosed to another 18 13–25 0% First same-sex romance 18 11–25 29% First disclosed to: Sibling 19 13–25 38% Father 19 13–25 44% Mother 19 13–25 31% Developed positive sexual identity 19 10–25 23% These numbers do not apply to samples of young men who have not acknowledged their same-sex attractions. Source: Savin-Williams, 1998a 456 n cHapTer 11 ATTACHMENT TO OTHERs AND DEVELOPMENT OF sELF Sometimes self-identification as gay, lesbian, or bisexual does not occur until after the individual has engaged in same-sex sexual activities. During this period, referred to as test and exploration, the individual may feel ambivalent about his or her same-sex attractions but eventually has limited sexual contact with gays or lesbians and starts to feel alienated from heterosexuality (Savin-Williams, 1998a). This contact may eventually lead to identity acceptance, which is marked by a pref- erence for social and sexual interaction with other sexual-minority individuals and the person’s coming to feel more positive about his or her sexual identity and disclosing it for the first time to heterosexuals (e.g., family or friends). (As noted, this latter stage, which involves self-identification, sometimes precedes sexual exploration.) Evidence regarding the sequencing of self-identification as a sexual-minority member and the commencement of same-sex sexual activity is mixed. The majority of individuals in all three groups in the above study self-identified prior to engaging in same-sex sexual activities. However, in a large study of gay men, same-sex sexual encounters were more likely to precede self-identification as gay (M. S. Friedman et al., 2008). Moreover, for many gay, lesbian, and bisexual youth and young adults, especially females, heterosexual activities occur prior to, or overlapping with, same- sex activities (L. M. Diamond, Savin-Williams, & Dube, 1999), which might affect the age of self-identification. The final step for some youth and adults is identity integration, in which gay, lesbian, and bisexual individuals firmly view themselves as such, feel pride in themselves and their particular sexual community, and publicly come out to many people. Often, arrival at this milestone is accompanied by anger over society’s prej- udice against members of sexual minorities (Savin-Williams, 1996; Sophie, 1986). Of course, not all individuals go through all these steps or go through them in the same order; some never fully accept their own sexuality or discuss it with others. Others—about one-third in one study—are “discovered” by their parents and do not disclose their sexual identity by choice (Rotheram-Borus & Langabeer, 2001). Consequences of Coming Out For the most part, sexual-minority youth typically do not disclose their same-sex preferences until late adolescence or a few years later (see Table 11.3; Calzo et al., 2011; M. S. Friedman et al., 2008), with only a minority revealing their sex- ual orientation before the age of 19 (D’Augelli & Hershberger, 1993; Herdt & Boxer, 1993; Savin-Williams & Diamond, 2000). When they do come out, sexual- minority youths usually disclose their same-sex preferences to a best friend (typi- cally a sexual- minority friend), to a peer to whom they are attracted, or to a sibling, and they do not tell their parents until a year or more later, if at all (Savin-Williams, 1998b). If they do reveal their sexual identity to their parents, they usually tell their mothers before telling their fathers, often because the mother asked or because they wanted to share that aspect of their life with their mother (Savin-Williams & Ream, 2003a). If sexual-minority youths are from communities or religious or ethnic back- grounds that are relatively low in acceptance of same-sex attractions, they are less likely than other sexual-minority youth to disclose their sexual preference to fam- ily members. For example, there is some evidence that non-White families in the United States, including Latino and Asian American families, are less accepting of same-sex attractions than are European American families (Dube et al., 2001). The effects of such low cultural acceptance are reflected in this statement from a young Asian American man: s E x U A L I D E N T I T Y O R O R I E N T A T I O N n 457 I am first generation from Southeast Asia. I am still very culturally bound and my . . . mother can’t fathom homosexuality, and many of our friends are the same. So I can’t express myself to my culture or to my family. It probably delayed my coming out. I wish I could have done it in high school like other kids. (Quoted in Savin-Williams, 1998a, pp. 216–217) Although many parents react in a supportive or only slightly negative man- ner to their children’s coming out, there is good reason for many sexual-minor- ity youth to fear disclosing their sexual identity to their family. It is not unusual for parents to initially respond to such a disclosure with anger, disappointment, and especially denial (Heatherington & Lavner, 2008; Savin-Williams & Ream, 2003a). Surveys indicate that a substantial portion of sexual-minority youth ex- perience threats or insults from relatives when they reveal their sexual orientation, and a small percent experience physical violence (Berrill, 1990; D’Augelli, 1998). Sexual-minority youth who disclose their sexual identity at a relatively early age, and those who are publicly open about their sexual identity, are often subjected to abuse in the home or community (Pilkington & D’Augelli, 1995). As might be expected, sexual-minority youth whose parents are accepting of their child’s sexual orientation report higher self-esteem and lower levels of depression and anxiety (Floyd et al., 1999; Savin-Williams, 1989a, b). Fear of being harassed or rejected outside the home is one reason many sexual- minority youth hide their sexual identity from heterosexual peers. In fact, many heterosexual adolescents are unaccepting of same-sex preferences in their peers (Bos et al., 2008; L. M. Diamond & Lucas, 2004; Pilkington & D’Augelli, 1995) and many sexual-minority youth report that having sexual-minority friends is im- portant in providing social support and acceptance (Savin-Williams, 1994, 1998a). For a variety of reasons, sexual-minority youth are vulnerable to a number of social and psychological problems. They are prone to experience negative affect, depression, low self-esteem, and low feelings of control in their romantic relation- ships (Bos et al., 2008; Coker, Austin, & Schuster, 2010; L. M. Diamond & Lucas, 2004). They also report higher levels of school-related problems and substance abuse than do other youth (Bos et al., 2008; Marshal et al., 2008). They are also more likely to be homeless or involved in street life, frequently because they have run away from, or been kicked out of, their home (Coker et al., 2010). Finally, sex- ual-minority youth have higher reported rates of attempted suicide than do their heterosexual peers (D’Augelli, Hershberger, & Pilkington, 2001; M. S. Friedman et al., 2011; Savin-Williams & Ream, 2003b). Some of these problems appear to be at least partly due to factors we have already noted, including poor relationships with, and sometimes physical abuse from, fam- ily members (Bos et al., 2008; M. S. Friedman et al., 2011; Ryan, 2009), along with victimization and harassment by peers and others in the community (Coker et al., 2010; M. S. Friedman et al., 2011; Martin-Storey & Crosnoe, 2012; Toomey et al., 2010). Additional contributing factors range from sexual abuse in childhood (M. S. Friedman et al., 2011) and discrimination (e.g., bullying from peers) (Saewyc, 2011) to a heightened tendency to engage in behaviors that pose a health threat (e.g., sub- stance use, eating disorders, and, among those who are sexually active, unprotected sex) (Busseri et al., 2008; Coker et al., 2010; Savin-Williams, 2006). Thus, it is likely that what contributes to these social and psychological problems can be attrib- uted to the consequences of being in the sexual minority rather than to same-sex attraction in itself. It must be noted, however, that the seemingly high rates of problems experienced by sexual-minority youth may be misrepresentative because they are often derived 458 n cHapTer 11 ATTACHMENT TO OTHERs AND DEVELOPMENT OF sELF from studies of youth who openly identify themselves as gay and who therefore, as mentioned earlier, are at increased risk of abuse or rejection by their family or community. In fact, estimates of suicide and other problems of adjustment are con- siderably lower in samples representative of sexual-minority youth overall (Savin- Williams, 2008) and in samples of youth who are attracted to same-sex individuals but have not yet identified themselves as gay (Savin-Williams, 2001a). Moreover, it is important to realize that, despite increased exposure to discrimination, abuses, and victimization, most sexual-minority youth achieve levels of adjustment similar to those of their heterosexual peers (Saewyc, 2011). review: Although in most respects, sexual-minority youths differ little from their peers, they may face special challenges in regard to their identity and disclosing their same-sex preferences to oth- ers. Typically, but not always, they move through the milestones of first recognition, test and exploration, identity acceptance (the order of the second and third milestones varies), and identity integration. Most sexual-minority youth have a sense of their sexual attractions by late adolescence, although some individuals report that they first experienced same-sex attractions in middle childhood or as late as their 30s. Because many sexual-minority youth initially have difficulty accepting their sexuality and fear revealing their sexual identity to others, they often do not tell others about their sexual preferences until mid-to-late adolescence or older. Parents sometimes have difficulty accepting their children’s same-sex orientation, and a minority of parents abuse or reject their children for this reason. Although sexual-minority youth usually come out first to a friend, they often fear harassment from peers. Perhaps because of the pressures associated with adjusting to their sexual identity, sexual-minority youth who have openly identified themselves as such to others appear to be more likely than other youth to attempt suicide, to be depressed, and to engage in risky behavior. Self-Esteem A key element of self-concept is self­esteem, or one’s overall evaluation of the self and the feelings engendered by that evaluation (Crocker, 2001). Self-esteem is im- portant because it is related to how satisfied people are with their lives and their overall outlook. Individuals with high self-esteem tend to feel good about them- selves and hopeful in general, whereas individuals with low self-esteem tend to feel worthless and hopeless (Harter, 1999). In particular, low self-esteem in childhood and adolescence is associated with problems such as aggression, depression, sub- stance abuse, social withdrawal, suicidal ideation (Boden, Fergusson, & Horwood, 2008; Donnellan et al., 2005; Rubin, Coplan, & Bowker, 2009; Sowislo & Orth, 2013), and cyberbullying (Modecki, Barber, & Vernon, 2013; S. J. Yang et al., 2013). Low self-esteem also predicts certain problems in adulthood, including mental health problems, substance abuse and dependence, criminal behavior, weak eco- nomic prospects, and low levels of satisfaction with life and with relationships (Boden et al., 2008; Orth, Robins, & Roberts 2008; Trzesniewski et al., 2006). However, it is not entirely clear if low self-esteem actually causes such problems or if both are due to a third factor. For instance, low self-esteem in children is often associated with their parents’ having such characteristics as low education, low income, and teenage maternity, as well as a history of alcohol or illicit drug use and criminal behavior. It may be that these parental characteristics, perhaps partly based on heredity, underlie both the children’s low self-esteem and their high rates of behavioral and psychological problems (Boden et al., 2008). It should also be noted that high self-esteem, especially if not based on positive self-attributes, may have costs for children and youths (K. Lee & Lee, 2012). For self-esteem n one’s overall evaluation of the worth of the self and the feelings that this evaluation engenders s E L F - E s T E E M n 459 example, high self-esteem in aggressive children is associated with their increas- ingly valuing the rewards that they derive from their aggression and their belittle- ment of victims (Menon et al., 2007). The combination of high self-esteem and narcissism—grandiose views of the self, inflated feelings of superiority and entitle- ment, and exploitative interpersonal attitudes—has been associated with especially high levels of aggression in young adolescents (Thomaes et al., 2008). Sources of Self-Esteem A number of factors are related to the development of children’s self-esteem. These include their genetic inheritance, the quality of their relationships with others, their appearance and competence, their school and neighborhood, and various cultural factors that impinge on their lives. In addition, how children think about them- selves in a wide variety of contexts contributes to their feelings of overall self-worth. Thus, the development of self-esteem offers a highly transparent example of the interaction of nature and nurture, including the sociocultural context. Moreover, it is a domain of functioning marked by large individual differences. To measure children’s self-esteem, researchers ask children, verbally or by ques- tionnaire, about their perceptions of themselves. As reflected in Table 11.4, the questions assess children’s sense of their own physical attractiveness, athletic com- petence, social acceptance, scholastic ability, and the appropriateness of their behav- ior. In addition, the researchers ask children about their global self-esteem—how they feel about themselves in general. TABLE 11.4 Sample Items from Susan Harter’s Self-perception profile for children, a commonly Used Measure of Self-esteem and Self-perceptions Really True for Me Sort of True for Me Sort of True for Me Really True for Me Scholastic Competence   Some kids feel that they are very good at their school work. BUT Other kids worry about whether they can do the school work assigned to them.   Social Acceptance   Some kids find it hard to make friends. BUT Other kids find it’s pretty easy to make friends.   Athletic Competence   Some kids do very well at all kinds of sports. BUT Other kids don’t feel that they are very good when it comes to sports.   Physical Appearance   Some kids are happy with the way they look. BUT Others kids are not happy with the way they look.   Behavioral Conduct   Some kids often do not like the way they behave. BUT Other kids usually like the way they behave.   Global Self-Esteem   Some kids are often unhappy with themselves. BUT Other kids are pretty pleased with themselves.   Source: Adapted from Harter, 1985 460 n cHapTer 11 ATTACHMENT TO OTHERs AND DEVELOPMENT OF sELF Heredity Heredity contributes to children’s sense of self-worth in several ways. The most obvious of these involve physical appearance and athletic ability, both of which are strongly related to self-esteem. In childhood and adolescence, attractive individu- als are much more likely to report high self-esteem than are those who are less attractive (Erkut et al., 1998; Harter, 2012), possibly because attractive people are viewed more positively by others and are treated better than unattractive people. Perhaps as a consequence, attractive people behave in more socially competent ways and are well-adjusted, which likely enhances their appeal to others (Langlois et al., 2000). The association between self-esteem and attractiveness may be stronger for girls than for boys, particularly in late childhood and adolescence, because girls are much more likely to report concerns about their appearance (see Figure 11.3). This gender difference may partly explain why boys report slightly higher self- esteem than do girls, especially in late adolescence (Kling et al., 1999). In addition, genetically based intellectual abilities and aspects of per- sonality, such as sociability, no doubt play a part in academic and social self-esteem (Harter, 1983; E. A. Skinner, Zimmer-Gembeck, & Connell, 1998), although self-esteem may also affect academic competence (X. Chen, He, & Li, 2004). The hereditary contribution to self-esteem is un- derscored by the fact that on a variety of dimensions, self-esteem is more similar in identical twins than in fraternal twins and in nontwin siblings than in stepsiblings (McGuire et al., 1994). Interestingly, the genetic contribution to self-esteem appears to be stron- ger for boys than for girls (Raevuori et al., 2007), perhaps, in part, because of the power and pervasiveness of certain environmental influences on girls’ self-esteem. Chief among these are the social norms and media messages regarding the importance of female beauty (Harter, 2012). A telling exam- ple of this is the emphasis that the media and peers put on the desirability of thinness, an emphasis that appears to contribute to some girls’ dissatisfaction with their bodies and themselves by the age of 8 (Dohnt & Tiggemann, 2006). Others’ Contributions to Self-Esteem One of the most important influences on children’s self-esteem is the approval and support they receive from others. This idea goes back more than a century to Charles Cooley’s (1902) proposal of the “looking glass self,” the concept that people’s self-esteem is a reflection of what others think of them (see Figure 11.4). More specifically, Cooley maintained that we develop our sense of self-esteem by internalizing the views that important others have of us. Similar ideas were proposed by Erikson (1950) and Bowlby (1969), who argued that children’s sense of self is grounded in the quality of their relationships with others. If children feel loved when young, they come to believe that they are lovable and worthy of others’ love; if they feel unloved when young, they come to believe the opposite. This view is supported by links between attachment status and children’s self-esteem or positive self-perceptions (Boden et al., 2008; Cassidy et al., 2003; Verschueren, Marcoen, & Schoefs, 1996). Moreover, parents who tend to be accepting and involved with their children and who use supportive yet firm child-rearing practices tend to have children and adolescents with high self- esteem (Awong, Grusec, & Sorenson, 2008; Behnke et al., 2011; S. M. Cooper & McLoyd, 2011; Lamborn et al., 1991). Support from nonparental adults such as teachers has likewise been associated with higher self-esteem in adolescents Appearance Females Males Social behavior Athletic and/or scholastic competence Conduct P er ce n t of s u b je ct s Domain of concern 50 40 30 20 10 0 FIGURE 11.3 Gender differences in adolescents’ concerns about their appear- ance, social behavior (how they treat sig- nificant others with whom they have a relationship), competence (athletic and/ or scholastic), and conduct (not behaving in ways that are not morally sanctioned) Girls report more concerns about their appearance and social behavior, and boys report more concerns about athletic and/or scholastic competence and their conduct. (adapted from Harter, 1999) Competence in domains of importance Self-esteem Approval support FIGURE 11.4 Factors contributing to children’s self-esteem children’s self- esteem is affected by the approval and sup- port they receive from parents, friends, and other people in their communities, as well as by their physical, social, behavioral, and academic competence, which are affected by both environmental and genetic factors. (adapted from Harter, 1999) s E L F - E s T E E M n 461 (Sterrett et al., 2011). In contrast, parents who regu- larly react to their children’s unacceptable behavior with belittlement or rejection—in effect, condemning the child rather than the behavior—are likely to instill in their chil- dren a sense of worthlessness and of being loved only to the extent that they meet parental standards (Harter, 1999, 2006; Heaven & Ciarrochi, 2008). Over the course of childhood, children’s self-esteem is increasingly affected by peer acceptance (Harter, 1999). Indeed, in late childhood, children’s feelings of competence about their appearance, athletic ability, and likability may be affected more by their peers’ evaluations than by their par- ents’. This tendency to evaluate the self on the basis of peers’ perceptions has been associated with a preoccupation with approval, fluctuations in self-esteem, lower levels of peer approval, and lower self-esteem (Harter, 2012). At the same time, children’s self-esteem likely affects how peers respond to them. Youth who see themselves as competent in their peer relationships tend to be well liked (M. S. Caldwell et al., 2004), perhaps because their behavior is confi- dent and socially engaging. In contrast to children, adolescents increasingly evaluate themselves on the basis of their own internalized standards rather than on the approval of others (Connell & Wellborn, 1991; Higgins, 1991). Adolescent girls’ self-esteem, for example, is in- creasingly linked to their feeling that they can have relationship authenticity—that is, that they can be themselves in terms of their thoughts and feelings in their social in- teractions (Impett et al., 2008). Experts agree that adolescents who continue to base their self-evaluations on others’ standards and approval are at risk for psychological problems, at least in Western industrialized cultures where an autonomous, relatively stable sense of self is valued (Damon & Hart, 1988; Harter, 2012; Higgins, 1991). School and Neighborhood Children’s and adolescents’ self-esteem can also be affected by their school and neighborhood environments. The effect of the school environment is most apparent in the decline in self-esteem that is associated with the transition from elementary school to junior high (Eccles et al., 1989). The junior high environment often is not a good developmental match for 11- and 12-year-olds because many children of that age are distressed by the switch from having one teacher whom they know well and who is well acquainted with their skills and weaknesses to having many teachers who know little about them. In addition, the transition to junior high forces students to enter a new group of peers and to go from the top of one school’s pecking order to the bottom of another’s. Especially in poor, overcrowded, urban schools, young ado- lescents often do not receive the attention, support, and friendship they need to do well and to feel good about themselves (Seidman et al., 1994; Wigfield et al., 2006). That children’s self-esteem can be affected by their neighborhood is suggested by the evidence that living in poverty in an urban environment, especially in vio- lent neighborhoods, is associated with lower self-esteem among adolescents in the United States (Behnke et al., 2011; Ewart & Suchday, 2002; Paschall & Hubbard, 1998; Turley, 2003). This may be due to high levels of stress that undermine the quality of parenting, prejudice from more affluent peers and adults, and inadequate material and psychological resources (Behnke et al., 2011; K. Walker et al., 1995). although far from being the only factors in shaping a child’s self-esteem, the quality and nature of interactions with parents and other caregivers are among the more impor- tant influences. G O LD E N P Ix E Ls L LC / A LA M Y children who do poorly in school tend to have lower self-esteem than do their more successful peers. However, children’s per- ceptions of their academic competence tend to be less important to their overall self- esteem than are their perceptions of their appearance. M A R Y K AT E D E N N Y / P H O T O E D IT 462 n cHapTer 11 ATTACHMENT TO OTHERs AND DEVELOPMENT OF sELF Self-Esteem in Minority Children Minority children in the United States generally are more likely than majority (European American) children to live in “undesirable,” impoverished neighbor- hoods and to be subjected to prejudice from both adults and peers, which can undermine children’s self-esteem (e.g., M. L. Greene et al., 2006; Seaton & Yip, 2009). Because children’s self-esteem is strongly influenced by the evaluations of others, it often is assumed that minority children, especially African American and Latino children, have lower self-esteem than do European American children. In fact, this is not always true. Although the self-esteem of young European Amer- ican children tends to be higher than that of their African American peers, after age 10, the trend reverses slightly. This shift most likely occurs because (1) African Ameri- cans tend to identify more with their racial group than do European Americans, and (2) African American culture, more than European American culture, emphasizes desirable aspects of the group’s distinctiveness (as reflected in the popular slogan from the 1960s and 1970s, “Black is beautiful”). Because ethnic identity is an important aspect of self-concept for many African Americans, this emphasis on the positive features of being African American may enhance African American adolescents’ and adults’ self-esteem (Gray-Little & Hafdahl, 2000; Herman, 2004). Less is known about the self-esteem of Latino and other minority children. Because of the poverty and prejudice that many Latino Americans experience, one might expect their self-esteem to be consistently much lower than that of Euro- pean Americans at all ages, and it is, at least through elementary school. Begin- ning in adolescence, however, the difference becomes much smaller (Twenge & Crocker, 2002). In part, this change may be due to the fact that Latino (e.g., Mexi- can American) parents encourage their children’s identification with the family and with the larger ethnic group (Parke & Buriel, 2006), which can provide a buffer against some of the negative effects that poverty and prejudice often have on self- esteem. Increases in Latino adolescents’ self-esteem are also associated with growth in their exploration of their ethnic identity (Umaña-Taylor et al., 2009). Especially in communities where Latinos are in the majority, Latino youth who identify with their ethnic group, in comparison with those who do not, tend to have higher self- esteem (Umaña-Taylor, Diversi, & Fine, 2002). Other minority groups in the United States show different patterns of self- esteem. Asian American children, for instance, report higher self-esteem in elementary school than do European Americans and African Americans, but by high school their reported self-esteem is lower than that of European Americans (Herman, 2004; Twenge & Crocker, 2002). In fact, in one recent study, Asian Americans were lower in self-esteem by sixth grade (Witherspoon et al., 2009). As we discuss in the next section, cultural factors may contribute to the lower levels of self-esteem reported in some ethnic-minority groups. Although discrimination can have a negative effect on adolescents’ self-esteem, how minority children and adolescents think about themselves is influenced much more strongly by acceptance from their family, neighbors, and friends than by reac- tions from strangers and the society at large (Galliher, Jones, & Dahl, 2011; Seaton, Yip, & Sellers, 2009). Thus, minority-group parents can help their children develop high self-esteem and a sense of well-being by instilling them with pride in their culture and by being generally supportive (Bámaca et al., 2005; Berkel et al., 2009; S. M. Cooper & McLoyd, 2011). For example, African American adolescents whose mothers support them and help them cope with problems hold more positive atti- tudes toward their race and express greater pride in being African American than do adolescents with less supportive mothers. In turn, this greater pride predicts lower s E L F - E s T E E M n 463 levels of perceived stress and, consequently, better adjustment (C. H. Caldwell et al., 2002). Having positive peer and adult role models from their own ethnic group also contributes to children’s positive feelings about themselves and their ethnicity (A. R. Fischer & Shaw, 1999; K. Walker et al., 1995). Culture and Self-Esteem In various cultures, the sources of self-esteem, as well as its form and function, may be different, and the criteria that children use to evaluate themselves may vary accordingly. Between Asian and Western cultures, for example, there are funda- mental differences that appear to affect the very meaning of self-esteem. In West- ern cultures, it is argued, self-esteem is related to individual accomplishments and self-promotion. In contrast, in Asian societies such as Japan and China, which traditionally have had a collectivist (or group) orientation, self-esteem is believed to be more related to contributing to the welfare of the larger group and affirm- ing the norms of social interdependence. In this cultural context, self-criticism and efforts at self-improvement may be viewed as evidence of commitment to the group (Heine et al., 1999). But in terms of standard measures of self-esteem (i.e., those used by U.S. researchers), this motivation toward self-criticism is reflected as lower self-evaluation (Harter, 2012). It is not surprising, then, that scores on standard measures of self-esteem vary considerably across these cultures. Except perhaps in the area of social competence, for instance, self-esteem scores tend to be lower in China, Japan, and Korea than in the United States, Canada, Australia, and some parts of Europe (Harter, 1999). These differences seem to be partly due to the greater emphasis that the Asian cultures place on modesty and self-effacement—which results in less positive self- descriptions (Cai et al., 2007; Suzuki, Davis, & Greenfield, 2008; Q. Wang, 2004). Indeed, the fact that European American and African American adolescents tend to be more comfortable with being praised and with events that make them look good and cause them to stand out than are Asian American and Latino adolescents (Suzuki et al., 2008) could affect the degree to which they report high self-esteem, and hence account for the pattern of ethnic differences in self-esteem (Harter, 2012). cultures differ in the skills they value. chil- dren learn what abilities are valued in their group through participation in the family and larger community and evaluate their own competence accordingly.RI C H A R D C U M M IN s / C O R B Is 464 n cHapTer 11 ATTACHMENT TO OTHERs AND DEVELOPMENT OF sELF In addition, in some Asian societies, people tend to be more comfortable acknowledging discrepancies in themselves—for example, the existence of both good and bad personal characteristics—than are people in Western cultures, and this tendency results in reports of lower self-esteem in late adolescence and early adulthood (Hamamura, Heine, & Paulhus, 2008; Spencer-Rodgers et al., 2004). The same types of cultural influences may affect measures of self-esteem in U.S. subcultures that have maintained traditional non-Western ideas about the self and its relation to other people. review: Many factors affect children’s and adolescents’ self-esteem. Genetic predispositions, the sup- port and approval of parents and peers, physical attractiveness, academic competence, and social factors such as the neighborhood and school environments all affect how children and youth feel about themselves. Although minority children in the United States often are exposed to prejudice and poverty, supportive families and communities can buffer and even enhance their self-esteem. The sources of self-esteem, as well as its form and function, may differ across cultures, and self-evaluations may differ accordingly. chapter summary: The Caregiver–Child Attachment Relationship n According to Bowlby’s theory, attachment is a biologically based process that is rooted in evolution and increases the helpless infant’s chance of survival. A secure attachment also provides children with a secure base for exploration. An out- come of early parent–caregiver interactions is an internal working model of relationships. n The quality of children’s attachment to their primary care- giver has been assessed using Ainsworth’s Strange Situation. Children typically are categorized as securely attached, inse- curely attached (insecure/resistant, insecure/avoidant), or disorganized/disoriented. Children are more likely to be securely attached if their caregivers are sensitive and responsive to their needs. n There are similarities in children’s attachments across many cultures, although the percentages of children in different attachment categories sometimes vary across cultures or subcultures. n Parents’ attachment status and their working models of rela- tionships are related to the quality of their attachment to their infants. There appears to be some continuity in attachment from childhood to adulthood, unless hardships such as divorce, illness, child maltreatment, or maternal depression occur between childhood and adulthood. n Intervention programs demonstrate that parents can be trained to be more sensitive, attentive, and stimulating in their par- enting and that these changes are associated with increases in infants’ sociability, exploration, ability to soothe themselves, and security of attachment. n Children’s security of attachment to their caregivers predicts quality of their future interpersonal relationships. Conceptions of the Self n Young children’s conceptions of themselves are very concrete— based on physical characteristics and overt behavior—and usu- ally positive. With age, conceptions of self increasingly become based on internal qualities and the quality of relationships with others; they also become more realistic, integrated, abstract, and complex. n According to Elkind, because of their focus on what others think of them, young adolescents think about an “imaginary audience” and develop “personal fables.” n According to Erikson, adolescence is marked by the crisis of identity versus identity confusion. The individual’s attempt to construct an identity, as well as whether and when the indi- vidual experiences a particular identity status (psychosocial moratorium, identity foreclosure, identity diffusion, or iden- tity achievement), is influenced by personal characteristics and familial and cultural factors. Ethnic Identity n In childhood, the development of an ethnic identity involves identifying oneself as a member of an ethnic group, devel- oping an understanding of ethnic constancy, engaging in ethnic-role behaviors, acquiring knowledge about one’s ethnic group, and developing a sense of belonging to the ethnic group. Family and community influence these aspects of development. C H A P T E R s U M M A R Y n 465 n In adolescence, minority youth often start to explore the meaning of their ethnicity and its role in their identity. Many ethnic-minority youth initially tend to be diffused or foreclosed in regard to their identities; then they become increasingly interested in exploring their ethnicity (search/ moratorium). Some come to embrace their ethnicity (ethnic- identity achievement); others gravitate toward the majority culture; still others become bicultural. Sexual Identity or Orientation n Sexual-minority (gay, lesbian, or bisexual) youth are sim- ilar to other youth in their development of identity and self, although they face special difficulties. Many have some awareness of their same-sex attractions by middle childhood. The process of self-labeling and disclosure among sexual- minority youth may involve several phases: first recogni- tion, test and exploration, identity acceptance, and identity integration. However, not all sexual-minority individuals go through all these stages, or go through them in the same order, and some individuals have difficulty accepting their sexuality-minority identity and revealing it to others. Self-Esteem n Children’s self-esteem is affected by many factors, including genetic predispositions, the quality of parent–child and peer relationships, physical attractiveness, academic competence, and various social factors. n Although minority children in the United States often are exposed to prejudice and poverty, supportive families and com- munities can buffer and even enhance their self-esteem. n Concepts of how a person should think and behave differ across cultures, with the consequence that self-evaluations and self-esteem scores differ in different cultures. Critical Thinking Questions 1. Some theorists believe that early attachment relationships have enduring long-term effects. Others think that such effects depend on the quality of the ongoing parent–child relationship, which tends to be correlated with the security of children’s early attachment to parents. How do you think researchers might go about examining this issue? 2. Based on what you have read about attachment and the development of the self, what negative effects might children experience as a result of being placed in a series of different foster-care homes? How might these effects vary with the age of the child? 3. What are the similarities and differences in the stages or phases of identity development as discussed by Erikson or Marcia (general identity development), Phinney (ethnic identity), and Savin-Williams (sexual-minority identity)? What factors might contribute to similarities and differ- ences? What variables might be especially relevant for ethnic identity and for identity in regard to sexual orientation? 4. What are some of the practical and conceptual difficulties of determining when children first recognize that they are physically attracted to same-sex or other-sex individuals? 5. Recall Erikson’s psychosocial stages of development (Chapter 9, pages 345–347). How might a person’s self-esteem be affected by the events and outcomes associated with each of the stages? Key Terms adult attachment models, p. 432 attachment theory, p. 428 attachment, p. 427 disorganized/disoriented attachment, p. 431 ethnic identity, p. 450 foreclosure status, p. 447 identity achievement, p. 446 identity confusion, p. 446 identity foreclosure, p. 447 identity versus identity confusion, p. 446 identity-achievement status, p. 448 identity-diffusion status, p. 447 imaginary audience, p. 444 insecure attachment, p. 431 insecure/avoidant attachment, p. 431 insecure/resistant (or ambivalent) attachment, p. 431 internal working model of attachment, p. 429 moratorium status, p. 447 negative identity, p. 447 parental sensitivity, p. 435 personal fable, p. 443 psychosocial moratorium, p. 447 secure attachment, p. 431 secure base, p. 428 self, p. 439 self-esteem, p. 458 sexual orientation, p. 453 sexual-minority youth, p. 454 social comparison, p. 443 Strange Situation, p. 430 466 © T H E P O T T E R IE S M U S E U M A N D A R T G A LL E R Y, S T O K E -O N -T R E N T, U K / T H E B R ID G E M A N A R T L IB R A R Y B E R N A R D F L E E T W O O D - WA L K E R , The Family, c. 1932 467 The Family n Family Dynamics Box 12.1: A Closer Look Parent–Child Relationships in Adolescence Review n The Role of Parental Socialization Parenting Styles and Practices The Child as an Influence on Parenting Socioeconomic Influences on Parenting Box 12.2: A Closer Look Homelessness Review n Mothers, Fathers, and Siblings Differences in Mothers’ and Fathers’ Interactions with Their Children Sibling Relationships Review n Changes in Families in the United States Box 12.3: Individual Differences Adolescents as Parents Older Parents Divorce Stepparenting Lesbian and Gay Parents Review n Maternal Employment and Child Care The Effects of Maternal Employment The Effects of Child Care Review n Chapter Summary chapter 12: 468 A s noted in Chapter 2, in 1979, the People’s Republic of China announced a sweeping new policy that would affect Chinese fami- lies dramatically. Because of the many problems associated with the country’s overpopulation, the government ordered a limit of one child per family in urban populations. Backed up by a system of economic rewards for those who complied and financial and social sanctions against those who did not, this policy was quite effective, especially in urban areas. For example, in Shanghai in 1985, 98% of births were first births; across the country, the figure was 68% (Poston & Falbo, 1990). The Chinese government estimates that, as of 2009, the policy had prevented 250 to 300 million births (Y. Wang & Fong, 2009). The one-child policy is controversial at a number of levels and has had a con- sequence that was unintended and grim: an epidemic of female abortion and in- fanticide arising from the cultural preference for male offspring. The controversies aside, however, the one-child policy provided developmental psychologists with an opportunity to study how a particular family structure might affect children’s devel- opment. Think about the differences in upbringing that might occur when parents have one child as opposed to two or more. To begin with, an only child is likely to receive more individual attention from parents and more of the family’s resources. In addition, an only child does not have to cooperate and share with siblings. Because of differences such as these, many people predicted that the new genera- tion of single children raised in the People’s Republic of China would be overin- dulged and have little experience in compromising and cooperating with others. Thus, there was concern that these single children (called “onlies”) would become spoiled “little emperors” (Falbo & Poston, 1993). Such a concern was not confined to China. An increase of one-child families in the United States likewise raised worries that single children would become spoiled brats (Falbo & Polit, 1986). In general, however, there is no consistent support for these concerns. There is some evidence that onlies in China, especially in urban areas, perform better on tests of academic performance and intelligence than do children from families with more than one child (Falbo & Poston, 1993; Falbo et al., 1989; Jiao, Ji, & Jing, 1996). And although some initial studies found that only children in China were viewed by peers as more self-interested and less cooperative than children with siblings (e.g., Jiao, Ji, & Jing, 1986), later studies found little evidence that only children have more behavioral problems (Hesketh et al., 2011; D. Wang et al., 2000; S. Zhang, 1997). Moreover, large survey studies do not indi- cate that onlies are more prone to depression and anxiety (G. D. Edwards et al., 2005; Hesketh & Ding, 2005), despite the potential for heightened family pressures on them to fulfill parental goals and needs. In fact, there appears to be virtually no difference between onlies and other children in regard to personality or social behavior, includ- ing positive behaviors needed for getting along with others, negative behaviors such as aggres- sion and lying, and respect and support for other family members (Deutsch, 2005; Falbo & Poston, 1993; Fuligni & Zhang, 2004; Poston & Falbo, 1990). The difference between the early and later findings may be due to a change in parents’ Themes n Nature and Nurture n The Active Child n The Sociocultural Context n Individual Differences n Research and Children’s Welfare A D R IA N B R A D S H A W / E P A / N E W S C O M The one-child policy in China provided an opportunity to assess the effects of being an only child. In general, only children in China are as well-adjusted as children from larger families and tend to do better in school. However, the one-child policy has resulted in the birth and survival of far more male children than female children, apparently due to selective abortion or female infanti- cide in order to have the opportunity to have a son. During the period of 2000 to 2004, approximately 124 boys were born for every 100 girls. It is estimated that in 2005 there were 32 million more males than females in China younger than age 20. T H E F A M I L Y n 469 behaviors toward only children as one-child families have become more common and expected, with the consequence that onlies are less likely to be spoiled. The one-child policy in China is a good example of how the structure of fami- lies can change and of how, consistent with Bronfenbrenner’s model discussed in Chapter 9 (pages 366–369), the larger world affects what goes on within families. Culture, as well as social and economic events, can have a tremendous effect on the structure of families and interactions among family members. In industrial- ized Western societies as well, a variety of social changes in the past 50 years have had marked effects on the structure of the family. For example, families are smaller than in the past, and many more people are choosing to have children outside of wedlock. In addition, it is not uncommon today for children to be reared by one biological parent or to live in a family that has experienced one or more divorces (Federal Interagency Forum on Child and Family Statistics, 2011). Such changes in the family can affect the resources available to the child, as well as the parents’ child-rearing practices and behavior. In this chapter, we examine many developmental aspects of family interaction, including the ways in which parents’ approach to parenting can influence their chil- dren’s development, the ways in which children can influence their parents’ par- enting, and the ways in which siblings may influence one another. In addition, we consider how family functioning and children’s development may have been affected by certain social changes that have occurred in the United States over the past seven decades—from the increased age of first-time parenthood to increased rates of divorce, remarriage, and maternal employment. We will also consider the impact that factors such as poverty and culture may have on developmental outcomes. As you will see, the theme of nature and nurture is central to the study of the role of the family because a child’s heredity and rearing influence each other and jointly affect the child’s development. In addition, the theme of the active child is evident in our discussion of how children influence the way their parents socialize them. The theme of sociocultural context is also key, in that parenting practices are strongly influenced by cultural beliefs, biases, and goals and are related to different outcomes for children in different cultures. Furthermore, the issue of individual differences is a major theme in this chapter because different styles of parenting, child-rearing practices, and family structures are associated with differences in chil- dren’s social and emotional functioning. Finally, because parenting influences the C U LT U R A C R E AT IV E / A LA M Y S T O C K B Y T E Among the many changes that have occurred in the American family over the past seven decades is a rise in the age of first marriage. 470 n CHApTer 12 THE FAMILY quality of children’s day-to-day experience, as well as children’s beliefs and behav- iors, understanding patterns of family functioning has relevance for our theme of research and children’s welfare. Family Dynamics Families fulfill several vital functions, including ensuring the survival of children to maturity, providing the means for children to acquire skills needed to be eco- nomically productive, and teaching children the basic values of the culture (R. A. LeVine, 1988). How well a family fulfills these basic child-rearing functions obviously depends on a great many factors. Not the least of these is family dynam- ics, that is, how the family operates as a whole. In subsequent sections, we discuss the ways in which individual family members contribute to a child’s development. However, it is important to frame these discussions with a clear appreciation of the overall impact of family dynamics. Families are complex social units whose mem- bers are all interdependent and reciprocally influence one another. Consider the diverse ways in which family members affect one another in the following scenario. A man loses his job because of company cutbacks, and the ensuing stress causes him to become very irritable with his wife and children. His wife, in turn, has to work extra hours to make ends meet, and her increasing fatigue makes her less patient with the children. The mother’s increased workload also means that the couple’s 8-year-old daughter is expected to do more of the house- hold chores. This makes the daughter angry because her 6-year-old brother is not required to help her out. Soon the daughter becomes hostile to both her parents and her brother. Not surprisingly, the brother starts to fight with his sister, further upsetting the parents. Over time, tension and conflict among all family members increase, adding to the stress created by the family’s economic situation. As researchers have increasingly focused on the complexity of family dynamics, a number of factors have become clear (Parke & Buriel, 1998). First, as illustrated by the foregoing example, all family members influence one another, both directly and indirectly, through their behaviors. Second, family functioning is influenced by the social support that parents receive from kin, friends, neighbors, and social institutions such as schools and churches (C.-Y. Lee, Lee, & August, 2011; Leidy, Guerra, & Toro, 2010; McConnell, Breitkreuz, & Savage, 2011) and is undermined by economic stresses (Riina & McHale, 2012). Thus, the sociocultural context is important for understanding family dynamics and their possible effects on chil- dren. Finally, family dynamics must be looked at developmentally. As children grow older, the nature of parent–child interactions changes. For example, as you saw in Chapter 5, when infants become independently mobile, parents start to dis- cipline them more to keep them out of harm’s way, and this can lead to tension and anger between parent and child ( J. J. Campos, Kermoian, & Zumbahlen, 1992). Similarly, as children experience increasing independence in adolescence, there sometimes is an increase in conflict between them and their parents over what is acceptable behavior (Laursen, Coy, & Collins, 1998). (See Box 12.1.) Family dynamics may also be altered by changes in parents (for example, in their beliefs about child rearing), in the marital relationship (for example, how well the parents are getting along), or in the relationships of other family mem- bers (for example, in the level of conflict between siblings). Alterations in the fam- ily structure due to births, deaths, divorce, remarriage, or other factors can also influence interactions among family members and may affect family routines and family dynamics n the way in which the family operates as a whole F A M I L Y D Y N A M I C S n 471 norms, as well as children’s emotional well-being (Bachman, Coley, & Carrano, 2012; Dush, Kotila, & Schoppe-Sullivan, 2011; Lam, McHale, & Crouter, 2012). In many cases, the effects of such shifts in family dynamics tend to be gradual and continuous. However, a single event such as a traumatic divorce or the death of a parent may cause a fairly dramatic change in a child’s behavior and emotional adjustment. In thinking about family dynamics, it is also important to keep in mind that the biological characteristics (e.g., temperament) of both children and parents, as well A common stereotype about adolescence is that, inevitably, conflict between parents and their children escalates dramatically and that parents and their adolescent children typically become alienated from one another. However, a good deal of research has shown that this simply is not true in most families (Fuligni, 1998; Laursen & Collins, 1994). As children advance through adolescence, they do, obviously, become more willing to disagree openly with their parents and feel that their parents should have less author- ity over them in personal matters (Fuligni, 1998; Youniss & Smollar, 1985). However, for the most part, disagreements between parents and adolescents, though fairly fre- quent and often intense in early and middle adolescence (Laursen et al., 2008), are usu- ally over mundane topics such as chores and attire. Moreover, the increase in mild con- flict and bickering between adolescents and their parents in early adolescence is typically followed by the establishment of a relation- ship that is less contentious and volatile, and more egalitarian (Steinberg, 1990; Steinberg & Morris, 2001; van Doorn et al., 2011). In a minority of families, however, parent– child conflict in adolescence runs hotter and deeper, often involving issues such as sex, drugs, and choice of friends (Arnett, 1999; Papini & Sebby, 1988). Higher levels of conflict seem especially likely when a child attains puberty earlier than his or her peers do (Collins & Steinberg, 2006; J. P. Hill, 1988; Steinberg, 1987, 1988). This may be because early maturation widens the gap between how much autonomy adolescents themselves think they deserve and how much autonomy their parents are willing to grant them. In addition, unlike their better- regulated peers, children who are unregu- lated and prone to negative emotions are likely to have particularly heated conflicts with their parents in adolescence about issues such as doing chores and respecting and getting along with other family members (N. Eisenberg et al., 2008). Such conflicts between adolescents and their mothers are associated with delinquency and externaliz- ing problems in youths (N. Eisenberg et al., 2008; Sentse & Laird, 2010; van Doorn et al., 2008). Although most parents and their adoles- cents are not alienated, feelings of close- ness and support between them often de cline, especially from the beginning of puberty through mid-adolescence (Fuligni, 1998; Shanahan et al., 2007; Steinberg, 1988). This decline is especially likely if the mother–child relationship is fairly neg- ative just prior to adolescence (Laursen, DeLay, & Adams, 2010). In addition, ado- lescents spend less time with their parents and more time with peers than do younger children (Dubas & Gerris, 2002; Larson & Richards, 1991). Thus, the decline in feel- ings of closeness seems due in part to the desire by adolescents to be more autono- mous and to an increase in their activities outside the home. Nonetheless, although peers are important confidants for adoles- cents (see Chapter 13), parents remain a primary source of support. BOX 12 .1: a closer look PARENT–CHILD RELATIONSHIPS IN ADOLESCENCE Most adolescents and their parents do not experience high levels of conflict. M O N IK A G R A F F / T H E I M A G E W O R K S 472 n CHApTer 12 THE FAMILY as parental behaviors, contribute to the nature of family interactions (Denissen, van Aken, & Dubas, 2009; Ganiban et al., 2011; Rasbash et al., 2011). For exam- ple, mothers’ negativity toward their children and the degree of parenting control they use appear to be affected partly by children’s heredity (including, perhaps, their tendency to experience and express negative emotion), whereas the degree to which mothers are close and affectionate with their children appears to be partly due to the mothers’ own genetic inheritance (Narusyte et al., 2008; Neiderhiser et al., 2004). With this larger framework of family dynamics in mind, we now turn to the role that parents play in the socialization of their children. review: Families are complex social units that serve diverse functions, including helping offspring to survive, to acquire the skills needed to be economically productive adults, and to learn the values of the culture. Family members’ behaviors influence one another and can alter the functioning of the entire family. Moreover, family dynamics are affected by a number of fac- tors, including changes in the parents, changes in the child over the course of development, and changes in family circumstances. The Role of Parental Socialization Socialization is the process through which children acquire the values, standards, skills, knowledge, and behaviors that are regarded as appropriate for their present and future roles in their particular culture. Parents typically contribute to their children’s socialization in at least three different ways (Parke & Buriel, 1998, 2006): n Parents as direct instructors. Parents may directly teach their children skills, rules, and strategies and explicitly inform or advise them on various issues. n Parents as indirect socializers. Parents provide indirect socialization through their own behaviors with and around their children. For example, in everyday actions, parents unintentionally demonstrate skills, communicate information and rules, and model attitudes and behaviors toward others. n Parents as social managers. Parents manage their children’s experiences and social lives, including their exposure to various people, activities, and informa- tion, especially when children are young. If parents decide to place their child in day care, for example, the child’s daily experience with peers and adult care- givers will likely differ dramatically from that of children whose daily care is provided at home. Parents use all these ways of socializing their children’s behavior and develop- ment. However, as you will see, parents differ considerably in how they do so. Parenting Styles and Practices As you undoubtedly recognize from your own experience, parents in different fam- ilies exhibit quite different parenting styles, that is, parenting behaviors and at- titudes that set the emotional climate of parent–child interactions. Some parents, for example, are strict rule setters who expect complete and immediate compliance from their children. Others are more likely to allow their children some leeway in parenting styles n parenting behav- iors and attitudes that set the emotional climate in regard to parent–child interac- tions, such as parental responsiveness and demandingness T H E R O L E O F P A R E N T A L S O C I A L I z A T I O N n 473 following the standards they have set for them. Still others seem oblivious to what their children do. Parents also differ in the overall emotional tone they bring to their parenting, especially with regard to the warmth and support they con- vey to their children. In trying to understand the impact that parents can have on children’s development, researchers have identified two dimensions of parenting style that are particu- larly important: (1) the degree of parental warmth, support, and acceptance, and (2) the degree of parenting control and demandingness (Maccoby & Martin, 1983). The pioneering research on parenting style was conducted by Diana Baumrind (1973), who differentiated among four styles of parenting related to the dimensions of support and control. These styles are referred to as authoritative, authoritarian, permissive, and rejecting-neglecting (Baumrind, 1973, 1991b) (Figure 12.1). The differences in these parenting styles are reflected in the following examples, which depict the way four different moth- ers respond when they observe their child taking away another child’s toy. 1. Authoritative. When Kareem takes away Troy’s toy, Kareem’s mother takes him aside and points out that the toy belongs to Troy and that Kareem has made Troy upset. She also says, “Remember our rule about taking other peoples’ things. Now think about how to make things right with Troy.” Her tone is firm but not hostile, and she waits to see if Kareem returns the toy. 2. Authoritarian. When Elene takes Mark’s toy, Elene’s mother comes over, grabs her arm, and says in an angry voice, “Haven’t I warned you about taking other people’s things? Return that toy now or you will not be able to watch TV tonight. I’m tired of you disobeying me!” 3. Permissive. When Jeff takes away Angelina’s toy, Jeff ’s mother does not intervene. She doesn’t like to discipline her son and usually does not try to control his actions. However, she is not detached as a parent and is affectionate with him in other situations. 4. Rejecting-neglecting. When Heather takes away Alonzo’s toy, Heather’s mother, as she does in most situations, pays no attention. She gener- ally is not very involved with her child. Even when Heather behaves well, her mother rarely hugs her or expresses approval of Heather or her behavior. According to Baumrind, authoritative parents, like Kareem’s mother, tend to be demanding but also warm and responsive. They set clear standards and limits for their children, monitor their children’s behavior, and are firm about enforcing important limits. However, they allow their children considerable autonomy within those limits, are not restrictive or intrusive, and are able to engage in calm conver- sation and reasoning with their children. They are attentive to their children’s con- cerns and needs and communicate openly with their children about them. They are also measured and consistent, rather than harsh or arbitrary, in disciplining them. Authoritative parents usually want their children to be socially responsible, assertive, and self-controlled. Baumrind found that children of authoritative par- ents tend to be competent, self-assured, and popular with peers. They are also able to behave in accordance with adults’ expectations and are low in antisocial behav- ior. As adolescents, they tend to be relatively high in social and academic compe- tence, self-reliance, and coping skills, and relatively low in drug use and problem Authoritative parenting D em an di ng ne ss h ig h lo w Responsiveness lowhigh Permissive parenting Authoritarian parenting Rejecting-neglecting parenting FIGURE 12.1 parental demandingness and responsiveness The relations of parental demandingness and responsiveness in Baumrind’s typology of parenting styles. authoritative parenting n a parenting style that is high in demandingness and supportiveness. Authoritative parents set clear standards and limits for their children and are firm about enforcing them; at the same time, they allow their children considerable autonomy within those limits, are attentive and responsive to their children’s concerns and needs, and respect and consider their children’s perspective. T O N Y F R E E M A N / P H O T O E D IT positive social and academic outcomes seem more likely when levels of parental warmth and control are both high. 474 n CHApTer 12 THE FAMILY behavior (Baumrind, 1991a; Driscoll, Russell, & Crockett, 2008; Hoeve et al., 2011; Lamborn et al., 1991). Authoritarian parents, much like Elene’s mother, tend to be cold and unre- sponsive to their children’s needs. They are also high in control and demanding- ness and expect their children to comply with their demands without question. Authoritarian parents tend to enforce their demands through the exercise of paren- tal power, especially the use of threats and punishment. Children of authoritarian parents tend to be relatively low in social and academic competence, unhappy and unfriendly, and low in self-confidence, with boys being more negatively affected than girls in early childhood (Baumrind, 1991b). High levels of authoritarian par- enting are associated with youths’ experiencing negative events at school (e.g., being teased by peers, doing poorly on tests) and ineffective coping with every- day stressors (Zhou et al., 2008), along with depression, aggression, delinquency, and alcohol problems (Bolkan et al., 2010; Driscoll et al., 2008; Kerr, Stattin, & Özdemir, 2012; Rinaldi & Howe, 2012). In studies by Baumrind and many others, parents’ control of children’s be- havior has been measured mostly in terms of the setting and enforcing of lim- its. Another type of control is psychological control—control that constrains, invalidates, and manipulates children’s psychological and emotional experience and expression. Examples include parents’ cutting off children when they want to express themselves, threatening to withdraw love and attention if they do not behave as expected, exploiting children’s sense of guilt, belittling their worth, and discounting or misinterpreting their feelings. These kinds of psychologi- cal control are more likely to be reported by children in relatively poor fami- lies. Their use by parents predicts children’s depression in late middle childhood and adolescence, as well as externalizing problems (e.g., aggression and delin- quency) ( Barber, 1996; Kuppens et al., 2012; Li, Putallaz, & Su, 2011; Soenens et al., 2008). However, parental use of psychological control may not always be a causal factor in children’s problem behaviors. For example, some adolescents who exhibit high levels of problem behaviors also engage in high levels of conflict with their mothers, which in turn, appears to elicit mothers’ use of psychological con- trol (Steeger & Gondoli, 2013). Permissive parents are responsive to their children’s needs and wishes and are lenient with them. Like Jeff ’s mother, they do not require their children to reg- ulate themselves or act in appropriate ways. Their children tend to be impul- sive, lacking in self-control, prone to externalizing problems, and low in school achievement (Baumrind, 1973, 1991a, 1991b; Rinaldi & Howe, 2012). As ado- lescents, they engage in more school misconduct and drug or alcohol use than do peers with authoritative parents (Driscoll et al., 2008; Lamborn et al., 1991). Rejecting-neglecting parents, such as Heather’s mother, are disengaged parents, low in both demandingness and responsiveness to their children. They do not set limits for them or monitor their behavior and are not supportive of them. Some- times they are rejecting or neglectful of their children altogether. These parents are focused on their own needs rather than their children’s. Children who experience rejecting-neglecting parenting tend to have disturbed attachment relationships when they are infants or toddlers and problems with peer relationships as children (Parke & Buriel, 1998; R. A. Thompson, 1998). In adolescence, they tend to ex- hibit a wide range of problems, from antisocial behavior and low academic com- petence to internalizing problems (e.g., depression, social withdrawal), substance abuse, and risky or promiscuous sexual behavior (Baumrind, 1991a, 1991b; Driscoll et al., 2008; Hoeve et al., 2011; Lamborn et al., 1991). The negative effects of this authoritarian parenting n a parenting style that is high in demandingness and low in responsiveness. Authoritarian par- ents are nonresponsive to their children’s needs and tend to enforce their demands through the exercise of parental power and the use of threats and punishment. They are oriented toward obedience and authority and expect their children to comply with their demands without ques- tion or explanation. permissive parenting n a parenting style that is high in responsiveness but low in demandingness. Permissive par- ents are responsive to their children’s needs and do not require their children to regulate themselves or act in appropriate or mature ways. rejecting-neglecting parenting n a disengaged parenting style that is low in both responsiveness and demanding- ness. Rejecting-neglecting parents do not set limits for or monitor their children’s behavior, are not supportive of them, and sometimes are rejecting or neglectful. They tend to be focused on their own needs rather than their children’s needs. T H E R O L E O F P A R E N T A L S O C I A L I z A T I O N n 475 type of parenting appear to continue to accumulate and worsen over the course of adolescence (Steinberg et al., 1994). In addition to the broad effects that different parenting styles seem to have for children, they also establish an emotional climate that affects the impact of what- ever specific parenting practices may be employed (Darling & Steinberg, 1993). For example, children are more likely to view punishment as being justified and indi- cating serious misbehavior when it comes from an authoritative parent than when it comes from a parent who generally is punitive and hostile. Moreover, parenting style affects children’s receptiveness to parents’ practices. Children are more likely to listen to, and care about, their parents’ preferences and demands if their par- ents are generally supportive and reasonable than if they are distant, neglectful, or expect obedience in all situations (Grusec, Goodnow, & Kuczynski, 2000; M. L. Hoffman, 1983). Although parenting style appears to have an effect on children’s adjustment, it is important to keep in mind that children’s behavior sometimes shapes parents’ typi- cal parenting style. In a recent study, adolescents’ reports of relatively high levels of externalizing problems (e.g., delinquency, loitering, and intoxication) and inter- nalizing problems (e.g., low self-esteem, depressive symptoms) predicted a decline in parents’ authoritative parenting styles (as reported by the youths) 2 years later, whereas an increase or decline in authoritative parenting over the same 2 years did not predict a change in the adolescents’ adjustment (Kerr et al., 2012). As noted previously, the family is a dynamic system, with each member having an effect on other members. Ethnic and Cultural Influences on Parenting In keeping with our theme of the sociocultural context, it is important to note that the effects of different parenting styles and practices may vary somewhat across ethnic or racial groups in the United States. Consider findings regarding restric- tive, highly controlling parenting. In contrast to the negative findings for European American children, researchers have found that for African American children, especially those in low-income families, this kind of parenting (e.g., involving in- trusiveness or unilaternal decision making) is associated with positive develop- mental outcomes such as high academic competence and low levels of deviant behavior (Dearing, 2004; Ispa et al., 2004; Lamborn, Dornbusch, & Steinberg, 1996; Tamis-LeMonda et al., 2008). Moreover, whereas parental use of physical discipline has been associated with high levels of problem behaviors for European American youths, such punishment is associated with relatively low levels for African American youths (Deater-Deckard et al., 1996; Lansford et al., 2004), especially when African American mothers believe measured physical punishment is an appropriate method for correcting misbehavior (McLoyd et al., 2007). One possible explanation for these findings is that many caring African American parents may feel the need to use authoritarian control to protect their children from special dangers, ranging from the risks found in crime-ridden neighborhoods to the prejudice experienced in predominantly affluent European American commu- nities (Kelley, Sanchez-Hucles, & Walker, 1993; Parke & Buriel, 2006; Smetana, 2011). In turn, African American youth may recognize the protective motive in their parents’ controlling practices and, consequently, respond relatively positively to their parents’ demands. This may be especially true in lower-income African American communities, where controlling, intrusive parenting is more normative than in many middle-class European American communities (Deater-Deckard 476 n CHApTer 12 THE FAMILY et al., 2011) and may be interpreted in a benign manner by African American children, especially if their parents are warm in other situations (Ispa et al., 2004; Tamis-LeMonda et al., 2008). Indeed, particular parenting styles and practices may also have different meanings, and different effects, in different cultures. For example, in European American families, authoritative parenting, as noted, seems to be associated with a close relationship between parent and child and with children’s positive psycho- logical adjustment and academic success. Although a somewhat similar relation between authoritative parenting and adjustment has been found in China, it tends to be weaker (Chang et al., 2004; Cheah et al., 2009; C. A. Nelson, Thomas, & de Haan, 2006; Zhou et al., 2004, 2008). In fact, some features of parenting that are considered appropriate in traditional Chinese culture are more characteris- tic of authoritarian parenting than of authoritative parenting. Compared with European American mothers, for example, Chinese American mothers are more likely to believe that children owe unquestioning obedience to their parents and thus use scolding, shame, and guilt to control them (Chao, 1994). Although such a pattern of parental control generally fits the category of authoritarian parenting, it appears to have few negative effects for Chinese American and Chinese children, at least prior to adolescence. Rather, for younger Chinese children, it is primarily physical punishment that is related to negative outcomes (N. Eisenberg, Chang et al., 2009; Zhou et al., 2004, 2008). A likely explanation is that in Chinese culture, children (but perhaps not ado- lescents) view parental strictness and emphasis on obedience as signs of paren- tal involvement and caring, and as important for family harmony (Chao, 1994; Yau & Smetana, 1996). Consistent with this idea, parents’ directiveness with their preschoolers—for example, telling the child what to do—is positively related to parental warmth/acceptance in China, whereas it is negatively related to this dimension in the United States (Wu et al., 2002). However, it is interesting to note that in some urban areas of China today, parental use of control appears to be rela- tively low compared with that in a number of other cultures (Deater-Deckard et al., 2011), probably as a result of exposure to Western child-rearing values. Cultural variation in the relation of parental warmth to parental control was highlighted by a study of families in the United States and 12 other countries. In this study, high levels of both warmth and control were found in African American and Hispanic American families, as well as in a number of other cultures in countries such as Italy, Kenya, Sweden, Colombia, Jordan, the Philippines, and Thailand. In contrast, European American families were characterized by moder- ately high warmth and low control, and these two dimensions of parenting were not correlated with each other. Although it is not clear why high warmth and high control go together in all the different groups mentioned above except European Americans, it is likely related to differences in the degree to which various cultures value high levels of parental control (Deater-Deckard et al., 2011). Because of variations such as these, findings regarding parenting styles in U.S. families—especially findings that involve primarily European American middle- class families—cannot automatically be generalized to other cultures or subcultures. Rather, the relation of parenting to children’s development must be considered in terms of the cultural context in which it occurs. Nonetheless, it should be noted that there are probably more similarities than differences in the parenting values and behaviors of various ethnic groups in the United States, as is strongly suggested by research that controls for socioeconomic status (e.g., N. E. Hill, Bush, & Roosa, 2003; Julian, McKenry, & McKelvey, 1994; Whiteside-Mansell et al., 2003). T H E R O L E O F P A R E N T A L S O C I A L I z A T I O N n 477 The Child as an Influence on Parenting Among the strongest influences on parents’ parenting style and practices are the char- acteristics of their children, such as their appearance, behavior, and attitudes. Thus, individual differences in children contribute to the parenting they receive, which, in turn, contributes to differences among children in their behavior and personalities. Attractiveness Although you might not want to think it is true, children’s physical appearance can influence the way their parents respond to them. For example, mothers of very attractive infants are more affectionate and playful with their infants than are mothers of infants with unappealing faces. Moreover, mothers of unappealing infants, compared with mothers of appealing ones, are more likely to report that their infants interfere with their lives (Langlois et al., 1995). Thus, from the first months of life, unattractive infants may experience somewhat different parenting than attractive infants. And this pattern continues throughout childhood, with attractive children tending to elicit more positive responses from adults than unat- tractive children do (Langlois et al., 2000). Children’s Behaviors and Temperaments Children’s influence on parenting through their appearance is, of course, a passive contribution. Consistent with the theme of the active child, children also actively shape the parenting process through their behavior and expressions of tempera- ment. Children who are disobedient, angry, or challenging, for example, make it more difficult for parents to use authoritative parenting than do children who are compliant and positive in their behavior (Cook, Kenny, & Goldstein, 1991; Crouter & Booth, 2003; Kerr et al., 2012). Differences in children’s behavior with their parents—including the degree to which they are emotionally negative, unregulated, and disobedient—can be due to a number of factors. The most prominent of these are genetic factors related to temperament (Saudino & Wang, 2012). At the same time, studies with twins A R IE L S K E LL E Y / C O R B IS Attractive children tend to elicit posi- tive interactions from adults, which likely helps to foster their social and emotional development. 478 n CHApTer 12 THE FAMILY indicate that environmental factors, likely including social interactions with fam- ily members, also affect infants’ and children’s temperament (Rasbash et al., 2011; Roisman & Fraley, 2006; Saudino & Wang, 2012). In addition, there appear to be genetically based differences in how children respond to their environment, including their parents’ caregiving. In line with our discussion of differential susceptibility in Chapter 10 (page 409), some children may be more reactive to the quality of parenting they receive than are others. For example, children with a difficult temperament often react worse (e.g., have more problems with adjust- ment or are less socially competent) when they receive nonsupportive or nonopti- mal parenting; however, these same children sometimes respond better when they receive supportive parenting (Beach et al., 2012; Kiff, Lengua, & Zalewski, 2011; Pluess & Belsky, 2010). Children’s noncompliance and externalizing problems offer further insight into the complex ways in which children can affect their parents’ behavior toward them. In resisting their parents’ demands, for example, children may become so whiny, aggressive, or hysterical that their parents back down, leading the children to resort to the same behavior to resist future demands (G. R. Patterson, 1982). By adoles- cence, those youths who are noncompliant and acting out, in part due to their he- redity, appear to evoke negativity from their parents to a greater degree than their parents’ negativity affects the youths’ externalizing problems (Marceau et al., 2013). Over time, the mutual influence, or bidirectionality, of parent–child interactions reinforces and perpetuates each party’s behavior (Combs-Ronto et al., 2009; Morelen & Suveg, 2012). One study, for example, found that children’s low self-regulation at age 6 to 8 (which may have been influenced by maternal behaviors at an earlier age) predicted mothers’ punitive reactions (e.g., scolding and rejection) to their children’s expressions of negative emotion at age 8 to 10. In turn, mothers’ punitive reactions when their children were age 8 to 10 predicted low levels of self-regulation in the children at age 10 to 12 (N. Eisenberg, Fabes et al., 1999) (Figure 12.2). A similar self-reinforcing and escalating negative pattern is common when parents are hostile and inconsistent in enforcing standards of conduct with their adolescent children; their children, in turn, are hostile, insensitive, disruptive, and inflexible with them (Conger & Ge, 1999; Rueter & Conger, 1998) and exhibit Parental Punitive reactions at 6–8 years Child Problem behavior at 6–8 years Child Problem behavior at 10–12 years Child Self-regulation at 6–8 years Parental Punitive reactions at 8–10 years Child Self-regulation at 8–10 years Parental Punitive reactions at 10–12 years Child Self-regulation at 10–12 years FIGURE 12.2 Bidirectional parent–child interactions In a study of elementary school children, children’s low self-regulation at ages 6 to 8 predicted parents’ punitive reactions when the children were 8 to 10 years of age, which, in turn, predicted the children’s relatively low self-regulation at ages 10 to 12. Both parental punitive reactions and children’s relatively low self-regu- lation at ages 10 to 12, as well as their problem behavior at a younger age, predicted externalizing problem behavior at ages 10 to 12. In addi- tion, parental punitive reactions, children’s self-regulation, and chil- dren’s problem behavior were all cor- related across time. (Adapted from N. eisenberg, Fabes et al., 1999) bidirectionality of parent–child interactions n the idea that parents and their children are mutually affected by one another’s characteristics and behaviors T H E R O L E O F P A R E N T A L S O C I A L I z A T I O N n 479 increased levels of problem behaviors (Roche et al., 2010; Scaramella et al., 2008). Bidirectional interaction is also a likely key factor in parent–child relationships that exhibit a pattern of cooperation, positive affect, harmonious communication, and coordinated behavior, with the positive behavior of each partner eliciting analogous positive behavior from the other (Aksan, Kochanska, & Ortmann, 2006; Denissen et al., 2009). Socioeconomic Influences on Parenting Another factor that is associated with parenting styles and practices is socioeco- nomic status. Parents with low SES are more likely than higher-SES parents to use an authoritarian and punitive child-rearing style; higher-SES parents tend to use a style that is more authoritative, accepting, and democratic (Pinderhughes et al., 2000; D. S. Shaw et al., 2004). Higher-SES mothers, for example, are less likely than low-SES mothers to be controlling, restrictive, and disapproving in their in- teractions with their young children ( Jansen et al., 2012), even in African Ameri- can families (Tamis-LeMonda et al., 2008) and non-Western cultures (X. Chen, Dong, & Zhou, 1997; von der Lippe, 1999). In addition, as discussed in Chapter 6 (page 235), higher-SES mothers talk more to their children, including about emotion (Garrett-Peters et al., 2008, 2011). They also elicit more talk from their children, and they follow up more directly on what their children say. This greater use of language by higher-SES mothers may foster better communication between parent and child, as well as promote the child’s verbal skills (B. Hart & Risley, 1995; E. Hoff, Laursen, & Tardif, 2002). Some of the SES differences in parenting style and practices are related to dif- ferences in parental beliefs and values (Bornstein & Bradley, 2003; E. A. Skinner, 1985). Higher-SES parents are more likely than lower-SES parents to view them- selves as teachers rather than as providers or disciplinarians (S. A. Hill & Sprague, 1999) and to feel more capable as young parents ( Jahromi et al., 2012). Both in the United States and in other Western countries, parents from lower-SES families often promote conformity in children’s behavior, whereas higher-SES parents are more likely to want their children to become self-directed and autonomous (Alwin, 1984; Luster, Rhoades, & Haas, 1989). It is likely that level of education is an important aspect of SES associated with differences in parental values and knowledge. Highly educated parents have more knowledge about parenting (Bornstein et al., 2010) and tend to hold a more com- plex view of development than do parents with less education. They are more likely, for example, to view children as active participants in their own learning and development ( J. Johnson & Martin, 1985; E. A. Skinner, 1985). Such a view may make high-SES parents more inclined to allow children to have a say in matters that involve them, such as family rules and the consequences for breaking them. It is important to recognize that SES differences in parenting styles and prac- tices may partly reflect differences in the environments in which families live. As we have noted, many low-SES parents may adopt a controlling, authoritarian par- enting style to protect their children from harm in poor, unsafe neighborhoods, especially those with high rates of violence and substance abuse. Correspondingly, it may be that higher-SES parents—being less economically stressed and freer of the need to protect their children from violence—have more time and energy to focus on complex issues in child rearing and may be in a better position to adopt an authoritative style, interacting with their children in a controlled yet flexible and stimulating manner (Hoff-Ginsberg & Tardif, 1995). 480 n CHApTer 12 THE FAMILY Economic Stress and Parenting Protracted economic stress is a strong predictor of quality of parenting, famil- ial interactions, and children’s adjustment, and the outcome for each is generally negative (McLoyd, 1998; Valenzuela, 1997). Moreover, economic pressures tend to increase the likelihood of marital conflict and parental depression, which, in turn, make parents more likely to be uninvolved with, or hostile to, their children ( Benner & Kim, 2010; Conger et al., 2002; Parke et al., 2004) and less likely to cooperate and support each other’s parenting (L. F. Katz & Low, 2004; Margolin, Gordis, & John, 2001; J. P. McHale et al., 2004). For both children and adolescents, the nonsupportive, inconsistent parenting associated with economic hardship and living in a poor neighborhood correlates with increased risk for depression, lone- liness, unregulated behavior, delinquency, academic problems, and substance use (Benner & Kim, 2010; Doan, Fuller-Rowell, & Evans, 2012; Kohen et al., 2008; Scaramella et al., 2008). The quality of parenting and family interactions is especially likely to be com- promised for families at the poverty level, which in 2010 included 32% of U.S. single-parent families headed by mothers and 6.2% of families headed by married adults. All told, about 22% of children younger than 18 years lived in poverty in the United States in 2010, the highest rate of child poverty among industrialized, Western coun- tries (National Poverty Center, 2013). (As Figure 12.3 shows, minority children are the most likely to be among this population.) At one time or another, a substantial number of families in poverty experience homelessness, which obviously makes effective parent- ing extremely difficult (see Box 12.2). One factor that can help moderate the potential impact of eco- nomic stress on parenting is having supportive relationships with relatives, friends, neighbors, or others who can provide material assistance, child care, advice, approval, or a sympathetic ear. Such positive connections can help parents feel more successful and sat- isfied as parents and actually be better parents (C.-Y. Lee et al., 2011; MacPhee et al., 1996; McConnell et al., 2011). Although social support for parents is generally associated with better parental functioning and child outcomes (Cardoso, Padilla, & Sampson, 2010; R. Feldman & Masalha, 2007; R. D. Taylor, Seaton, & Dominguez, 2008), it may be less beneficial for low-income parents in the poorest, most dangerous neighborhoods (Ceballo & McLoyd, 2002) and for depressed parents (R. Taylor, 2011). In considering the effects of economic stress on parenting, it is important to bear in mind that individuals contribute to their own socioeconomic situation through their traits, dispositions, and goals, and these same traits, dispositions, and goals are likely to influence their relations with their children and their chil- dren’s behavior. For example, when investigators took into account adolescents’ initial level of socioeconomic status, they found that youths with personality characteristics that reflected positive social skills, regulation, goal-setting, and hard work were more likely to attain a higher income and educational level at an older age than were youths who lacked those traits; and their children, in turn, exhibited high levels of positive development (Schofield et al., 2011). Simi- larly, adolescents with lower levels of problem behavior tended, over time, to attain higher socioeconomic status and to be more emotionally invested in their children, and their children, in turn, exhibited fewer problem behaviors (M. J. White only non-Hispanic Black Hispanic Asian 0 10 20 30 40 P er ce n t All children under 18 FIGURE 12.3 Child poverty rates in the United States Minority children in the United States—especially African American and Hispanic American children—are more than three times more likely to live in pov- erty than are european American children. (Adapted from DeNavas-Walt, proctor, & Smith, 2011) 481 BOX 12 .2: a closer look HOMELESSNESS It is impossible to know the precise num- ber of homeless children and families in the United States, much less in the world. In some countries, such as India and Brazil, the figure is in the millions (Diversi, Filho, & Morelli, 1999; Verma, 1999). In the United States, it is estimated that 3 million people are homeless at some point over the course of a given year, including 1.6 million children (1 in 45), approximately 650,000 of whom are younger than 6. Many homeless children are in the care of at least one parent, most often a single mother (National Law Center on Homelessness and Poverty, 2012; United States Conference of Mayors, 2009). Homeless children are at risk in a vari- ety of ways. At the most basic level, they are often malnourished and lack adequate medi- cal care. Frequently, they are also exposed to the chaotic and unsafe conditions found in many shelters. They are also at increased risk both of being sexually abused (Buckner et al., 1999) and of ending up in foster care (Zlotnick et al., 1998). As might be expected, homeless children’s school performance tends to be poor and is commonly accompa- nied by absenteeism and serious behavioral problems (Masten et al., 1997; Obradović et al., 2009; Tyler et al., 2003). Excep- tions to this pattern tend to include children who have a close relationship with their par- ents, especially if their parents are involved in their education ( Masten & Sesma, 1999; Miliotis et al., 1999), and children who are temperamentally well regulated (Obradović, 2010). Compared with poor children who are not homeless, homeless children also experience more internalizing problems, such as depression, social withdrawal, and low self-esteem (Buckner et al., 1999; DiBiase & Waddell, 1995; Rafferty & Shinn, 1991). However, those who are well regulated tend to be better adjusted and to get along better with peers (Obradović, 2010). In adolescence, numerous youths either choose to leave their homes or are kicked out, and many of them live on the streets. Estimates of homeless, runaway, or “thrown away” adolescents in the United States (many of whom may not be included in home- less statistics) range from about 575,000 to more than 1.6 million (e.g., Urbina, 2009). Predictors of youths’ running away include their living in lower-income families and neighborhoods, living in a home without two biological parents, and experiencing peer victimization and school suspension (Tyler & Bersani, 2008; Tyler, Hagewen, & Melander, 2011). In comparison with other adolescents from the same neighborhoods, these home- less youths generally report having experi- enced more conflict with, and rejection by, their parents and more parental maltreat- ment, including physical abuse, not infre- quently due to their sexual orientation. They also often exhibited problem behaviors when they were at home (Tyler et al., 2011). How- ever, these differences seem to be based in part on differences in the parents’ behavior toward the children or in levels of stress in the home; they do not seem to be due merely to the homeless children’s having had more problems of adjustment (American Psycho- logical Association, 2013; Tyler et al., 2011; Wolfe, Toro, & McCaskill, 1999). In many third-world countries, homeless children often live with other children on the streets and report doing so because of the loss of their parents or because of sexual, mental, or physical abuse at home (Aptekar & Ciano-Federoff, 1999). In many cases, children living on the streets reside at least part of the time with a parent or other relative (Diversi et al., 1999; Verma, 1999). Some youths report that they stay on the streets in order to enjoy freedom with their friends (J. J. Campos et al., 1994; Sampa, 1997). Life on the streets in most third-world countries is even riskier than it is in the United States. In one study of Brazilian street youth, 75% were engaged in illegal activities such as stealing and prostitution (J. J. Campos et al., 1994). The longer these children were on the streets, the more likely they were to be involved in illegal activities. Compared with peers who hung out on the street but usually slept in homes, street chil- dren also were at greater risk for drug abuse and began sexual activities at a younger age. Thus, it is clear that homelessness, wherever it occurs, takes a tremendous toll on the wel- fare of children and on the larger society. Children in homeless families, including those living in shelters, are at risk for depression, behavioral problems, and academic failure. A P P H O T O / A M Y S A N C E T TA Homeless youth are at high risk for becoming involved in drugs and prostitution. JA N IN E W IE D E L P H O T O LI B R A R Y / A LA M Y 482 n CHApTer 12 THE FAMILY Martin et al., 2010). Such findings support an interactionist model of socioeco- nomic influence on human development, in which the association between SES and developmental outcomes reflects both social causation (SES influences de- velopmental outcomes) and social selection (individual characteristics influence SES) (Conger, Conger, & Martin, 2010). review: Styles of parenting are associated with important developmental outcomes. Researchers have delineated four basic parenting styles varying in parental warmth and control: authori- tative (relatively high in control and high in warmth); authoritarian (high in control but low in warmth); permissive (high in warmth and low in control); and rejecting-neglecting (low in both warmth and control). Particular styles of parenting can affect the meaning and impact of specific parenting practices, as well as children’s receptiveness to these practices. In addition, the significance and effects of different parenting styles or practices may vary some- what across cultures. Education and income are associated with variations in parenting. Economic stressors can undermine the quality of marital interactions and parent–child interactions. Children in poor and homeless families are more at risk for serious adjustment problems, such as depression, academic failure, disruptive behavior at school, and drug use. Mothers, Fathers, and Siblings As part of their focus on family dynamics, developmentalists have examined differ- ences in children’s interactions with mothers, fathers, and siblings. They have been particularly interested in these two questions: How do mothers and fathers differ in their parenting? How do siblings affect one another? Differences in Mothers’ and Fathers’ Interactions with Their Children It will come as no surprise that there is a great deal of difference, both quan- titative and qualitative, between mothers’ and fathers’ interactions with their children. Although in most Western cultures today spouses share child-care re- sponsibilities to some degree, in the majority of families, mothers—including those who work outside the home—still spend considerably more time with their children than fathers do (Biehle & Mickelson, 2012; Dubas & Gerris, 2002; Gaertner et al., 2007). In the United States, this pattern seems to hold across the major ethnic groups, continuing from the early years into adolescence (Parke & Buriel, 1998). Fathers’ participation in child care differs from mothers’ not only in amount but also in kind. Mothers are more likely to provide physical care and emotional support than are fathers (M. Moon & Hoffman, 2008; G. Russell & Russell, 1987). In contrast, fathers in modern industrialized cultures spend a greater proportion of their available time playing with their children than do mothers, both in infancy and childhood, and the type of play they engage in differs from mothers’ play as well (Parke & Buriel, 1998). In an Australian study, for example, fathers were more likely to engage their children in physical and outdoor play activities (e.g., rough-and-tumble play and playing ball) than were mothers (G. M O T H E R S , F A T H E R S , A N D S I B L I N G S n 483 Russell & Russell, 1987). Mothers, on the other hand, were likelier to play more reserved games with their children (e.g., peekaboo), to read to them, and to join them in play with toys indoors (Parke, 1996; G. Russell & Russell, 1987). Although these general patterns prevail in many cultures, there are also some cultural variations. Fathers in Sweden, Malaysia, and India, for example, do not report much play at all with their children (C. P. Hwang, 1987; Roopnarine, Lu, & Ahmeduzzaman, 1989). Indeed, both mothers and fa- thers in some cultures simply play less with their children than American parents do (Göncü, Mistry, & Mosier, 2000; Roopnarine & Hossain, 1992). In a study of Gusii infants and parents in Kenya, fathers were seldom seen within 5 feet of their infants, and mothers spent 60% less time playing with infants than American mothers typically do (R. A. LeVine et al., 1996). The degree of maternal and paternal involvement in parenting and the nature of parents’ interactions with chil- dren doubtlessly vary as a function of cultural practices and such factors as the amount of time parents work away from home and children spend at home. Economic and educational factors also seem to be related to the degree to which mothers engage in various caregiving activities. In a study of mothers in 28 developing countries who had children younger than 5, those in countries that had higher levels of education and higher gross national product were more likely to engage in caregiving activities that are cognitively stimulating (e.g., reading books, counting, naming objects) and were less likely to leave their children alone or in the care of another child younger than 10. It is likely that cultural differences in the importance placed on literacy and cognitive growth account for these differences in mothers’ caregiving activities (Bornstein & Putnick, 2012). Sibling Relationships Siblings influence one another’s development and the functioning of the larger fam- ily system in many ways, both positive and negative. They serve not only as play- mates for one another but also as sources of support, instruction, security, assistance, and caregiving (G. H. Brody et al., 1985; Gamble et al., 2011; Gass, Jenkins, & Dunn, 2007). Siblings, of course, also can be rivals and sources of mutual conflict and irritation (Vandell, 1987). And, in some cases, they can contribute to the devel- opment of a sibling’s undesirable behaviors, such as disobedience, delinquency, and drinking (Bank, Patterson, & Reid, 1996; Low, Shortt, & Snyder, 2012; Slomkowski et al., 2001), especially if they live in disadvantaged neighborhoods (G. H. Brody et al., 2003). Low-quality sibling relationships also are associated with higher lev- els of siblings’ depression, anxiety, and social withdrawal (Compton et al., 2003; S. M. McHale et al., 2007; Morgan et al., 2012). In addition, sibling aggression and conflict rather than closeness are related to children’s lack of self-regulation (Padilla-Walker, Harper, & Jensen, 2010) and risky sexual behavior (S. M. McHale, Bissell, & Kim, 2009), as well as externalizing problems (Bascoe, Davies, & Cummings, 2012; Natsuaki et al., 2009; Padilla-Walker et al., 2010). T H IN K S T O C K / G E T T Y I M A G E S Fathers tend to engage in more physical play with their children than do mothers. 484 n CHApTer 12 THE FAMILY Numerous factors affect whether siblings get along with each other. Siblings’ rela- tionships tend to be less hostile and more supportive, for example, when their par- ents are warm and accepting of them (Grych, Raynor, & Fosca, 2004; Ingoldsby, Shaw, & Garcia, 2001; J.-Y. Kim et al., 2006). Siblings also have closer, more posi- tive relationships with each other if their parents treat them similarly (G. H. Brody et al., 1992; S. M. McHale et al., 1995). If parents favor one child over another, the sibling relationship may suffer, and the less favored child may experience distress, depression, and other problems with adjustment, especially if the child does not have a positive relationship with his or her parents (Feinberg & Hetherington, 2001; Meunier et al., 2013; Shanahan et al., 2008; Solmeyer et al., 2011). Differential treatment by parents is particularly influential in early and mid- dle childhood, with less favored siblings being likelier to experience worry, anxi- ety, or depression than are their more favored siblings (Coldwell, Pike, & Dunn, 2008; Dunn, 1992). By early adolescence, however, children often view parents’ differential treatment of them as justified because of differences they perceive between themselves and their siblings in age, needs, and personal characteristics. When children view differen- tial treatment by parents as justified, they report more positive relationships with their sibling and their par- ents than when they feel that differential parental treat- ment is unfair (Kowal & Kramer, 1997; Kowal, Krull, & Kramer, 2004; S. M. McHale et al., 2000). Cultural values may play a role in children’s evaluations of, and reactions to, differential parental treatment. For example, in a study of Mexican American families, older siblings who embraced the cultural value of familism, which emphasizes interdependence, mutual support, and loyalty among family members, were not put at risk of higher levels of depressive symptoms or risky behaviors by their parents’ preferential treatment of younger siblings (S. M. McHale et al., 2005). F LO R IA N F R A N K E / A LA M Y The quality of parents’ relationships with their children is related to how well siblings interact. LA U R A D W IG H T Young children are more likely than older children to respond poorly when they per- ceive that an infant sibling receives more attention than they themselves do. C H A N G E S I N F A M I L I E S I N T H E U N I T E D S T A T E S n 485 Another factor that can affect the quality of siblings’ interactions is the nature of the parents’ relationship with each other. Siblings get along better if their par- ents are getting along with each other (Erel, Margolin, & John, 1998; McGuire, McHale, & Updegraff, 1996). In contrast, siblings whose parents fight with each other are likely to have more hostile interactions because their parents not only model negative behavior for their children but also may be less sensitive and ap- propriate in their efforts to manage their children’s interactions with one another (N. Howe, Aquan-Assee, & Bukowski, 2001). Rivalry and conflict between siblings tend to be higher in divorced families and in remarried families than in nondivorced families, even between biological sib- lings. Although some siblings turn to one another for support when their parents divorce or remarry ( Jenkins, 1992), they may also compete for parental affection and attention, which often are scarce in these situations. Relationships between half-siblings can be especially emotionally charged, perhaps because the older sib- ling may resent the younger sibling who is born to both parents in the new marital relationship (Hetherington, 1999). In general, the more a child in a blended family perceives a parent’s preferential treatment of a sibling—whether a full sibling or a half-sibling—the worse the child’s relationship is with that sibling (Baham et al., 2008). Thus, the quality of sibling relationships differs across families depending on the ways that parents interact with each child and with each other and children’s perceptions of their treatment by other family members. Such differences highlight the fact that families are complex, dynamic social systems and that all members contribute to one another’s functioning. review: Mothers typically interact with their children much more than fathers do. The nature of mother–child and father–child interactions also tends to differ, with fathers engaging in more physical play with their children. Parent–child interactions differ across cultures; for exam- ple, in some cultures, parents play little or not at all with their children. Siblings are important contributors to one another’s socialization and development. They can be sources of learning and support, as well as rivalry and conflict. Siblings get along bet- ter if they have good relationships with their parents and if they do not feel that their parents treat them differently. Sibling relationships are, on average, more hostile and conflicted in divorced and remarried families than in nondivorced families. Thus, sibling relationships, like all family relationships, must be viewed in the context of the larger family system. Changes in Families in the United States The family in the United States has changed dramatically since the middle of the twentieth century. For example, from the 1950s to 2008, the median age at which people first married rose from age 20 to nearly 25.6 for women and from age 23 to over 27.4 for men (Cherlin, 2010; Goodwin, McGill, & Chandra, 2009). Over this same period, the economic arrangement of the U.S. family also changed quite strikingly. In 1940, the father was the breadwinner and the mother was a full-time homemaker in 52% of nonfarm families (D. J. Hernandez, 1993). In contrast, in 2009 about 74% of mothers with children younger than 15 worked at least part time outside the home (Kreider & Elliott, 2010). A third change that occurred in the family, partly as a result of the two just men- tioned, was that the average age at which women bore children increased, especially 486 n CHApTer 12 THE FAMILY within marriages. The mean age of first-time motherhood rose from 21.4 in 1970 to 25.4 in 2010. At the same time, births to mothers between ages 15 and 19 declined, dropping from 36% of total births in 1970 to 9.2% in 2010, the lowest rate since 1946 ( J. A. Martin et al., 2012) (see Box 12.3). Two of the most far-reaching changes in the U.S. family in the past half century have been the upsurge in divorce and the increase in the number of children born to unwed mothers. The divorce rate more than doubled between 1960 and 1980 and was between 40% and 50% in 2010 (Cherlin, 2010; Coltrane, 1996). The rise in out-of-wedlock births began in the 1980s. In 1980, 18% of all births were to unmarried women; in 2009, the figure was 41%, including 94% of births for 15- to 17-year-olds (Federal Interagency Forum on Child and Family Statistics, 2011; see Figure 12.4 on page 488). However, it is important to note that about half the unmarried women who give birth are cohabiting with the fathers of their children (Kennedy & Bumpass, 2008). Childbearing in adolescence is a common occurrence in the United States. Among 15- to 17-year-olds in 2010, the rate of births was 17.3 per 1000 females (J. A. Martin et al., 2012). This rate, a decline of 55% from 1991 (which was the peak year for such births), was the lowest rate in the seven decades for which national data are available. This decline is likely due in part to the greater availability of birth control and abortions. Nevertheless, the current rate is still much higher than that in other industrialized coun- tries (R. L. Coley & Chase-Lansdale, 1998). A number of factors affect U.S. girls’ risk for childbearing during adolescence. Two factors that reduce the risk are living with both biological parents and being involved in school activities and religious organiza- tions (B. J. Ellis et al., 2003; K. A. Moore et al., 1998). Factors that substantially in- crease the risk include being raised in pov- erty by a single or adolescent mother (R. L. Coley & Chase-Lansdale, 1998; J. B. Hardy et al., 1998), low school achievement and dropping out of school (Freitas et al., 2008), significant family problems (e.g., death of a parent, drug or alcohol abuse in the family; Freitas et al., 2008), and having an older adolescent sibling who is sexually active or is already a parent (East & Jacobson, 2001; B. C. Miller, Benson, & Galbraith, 2001). For young adolescent girls, having a mother who is cold and uninvolved may increase the risk of their becoming pregnant in later adolescence. In part, this may be because girls whose mothers fit this pattern tend to do poorly in school and hang out with peers who get into trouble, which often leads to risk taking and pregnancy (Scaramella et al., 1998). In fact, girls who are at risk for becoming mothers as teenagers tend to have many friends who are sexually active (East, Felice, & Morgan, 1993; Scaramella et al., 1998). It is likely that girls’ willingness to engage in sex is influenced by its acceptabil- ity in their group of friends. Having a child in adolescence is associ- ated with many negative consequences for both the adolescent mother and the child (Jaffee, 2002). Motherhood curtails the mother’s opportunities for education, ca- reer development, and normal relationships with peers. Even if teenage mothers marry, they are very likely to get divorced and to spend many years as single mothers (R. L. Coley & Chase-Lansdale, 1998; M. E. Lamb & Teti, 1991; M. R. Moore & Brooks-Gunn, 2002). In addition, adolescent mothers often have poor parenting skills and are more likely than older mothers to provide low levels of verbal stimulation to their infants, to expect their children to behave in ways that are beyond their years, and to neglect and abuse them (Culp et al., 1988; Ekéus, Christensson, & Hjern, 2004; M. E. Lamb & Ketterlinus, 1991). Given these deficits in parenting, it is not surprising that children of teenage mothers are more likely than children of older moth- ers to exhibit disorganized attachment sta- tus, low impulse control, problem behaviors, and delays in cognitive development in the preschool years and thereafter. As adoles- cents themselves, children born to teenag- ers have higher rates of academic failure, delinquency, incarceration, and early sexual activity than do adolescents born to older mothers (R. L. Coley & Chase-Lansdale, 1998; M. R. Moore & Brooks-Gunn, 2002; Wakschlag et al., 2000). Not surprisingly, they also tend to have less education, in- come, and life satisfaction as young adults (Lipman et al., 2011). This does not mean that all children born to adolescent mothers are destined to poor developmental outcomes. Those whose mothers have more knowledge about child development and parenting and who exhibit more authoritative parenting than most teen mothers do tend to display fewer problem behaviors and better intellectual development (L. Bates, Luster, & Vanden- belt, 2003; C. L. Miller et al., 1996). In addition, those who experience a positive mother–child relationship, including con- sistent and sensitive parenting, appear more likely to stay in school and obtain employment in early adulthood (Jaffee et al., 2001). Supportive parents and other BOX 12 .3: individual differences ADOLESCENTS AS PARENTS C H A N G E S I N F A M I L I E S I N T H E U N I T E D S T A T E S n 487 relatives are also likely to provide child care so that young mothers have the opportunity to continue their schooling. A number of factors likewise affect ado- lescent males’ risk for becoming fathers. Chief among these are being poor, being prone to substance abuse and behavioral problems, being involved with deviant peers, and having a police record (Fagot et al., 1998; Miller-Johnson et al., 2004; D. R. Moore & Florsheim, 2001). Many young unmarried or absent fathers see their children regularly, at least dur- ing the first few years, but rates of contact decrease over time (R. L. Coley & Chase- Lansdale, 1998; Marsiglio et al., 2000). In one study, 40% of adolescent fathers had no contact with their 2-year-old children (Fagot et al., 1998). Contact is less likely to be main- tained when the unmarried noncohabiting father is an adolescent (M. Wilson & Brooks- Gunn, 2001). Young unmarried fathers remain more involved with their children if they have a warm, supportive relationship with the mother in the weeks after delivery and if the mother does not experience many stressful life events (particularly financial problems) during and soon after the preg- nancy (Cutrona et al., 1998). They are also more likely to be involved with their infants if they have social support from their own par- ents for the parenting role, and if their level of stress related to fatherhood or other factors is low (Fagan, Bernd, & Whiteman, 2007). The presence and support of the father can be beneficial to both the child and the mother. Adolescent mothers feel more competent as a parent and less likely to be depressed when they are satisfied with the level of the father’s involvement (Fagan & Lee, 2010). The children of adolescent mothers fare better in their own adolescence if they have a good relationship with their biological father (or a stepfather), especially if he lives with the child. However, exposure to a fathering figure may have little benefi- cial effect on children of adolescent mothers if the father–child relationship is not posi- tive or the father figure has a criminal history (Furstenberg & Harris, 1993; Jaffee et al., 2001). JO H N B E R R Y / S Y R A C U S E N E W S P A P E R S / T H E I M A G E W O R K S Teenage mothers tend to be daughters of teenage mothers and to have sexually active sisters and friends. Due both to the increase in divorce and the increase in the birthrate among unmarried women, the percentage of children living with two married parents fell from 77% in 1980 to 66% in 2010. In 2010, 23% of children lived with only their mother, 3% lived with only their father, 4% lived with two unmar- ried parents, and 4% lived with neither parent—that is, with a grandparent, other relative, or a nonrelative (Federal Interagency Forum on Child and Family Statistics, 2011). Although people are more likely to divorce than in the past, most divorced people also remarry. Indeed, 54% percent of divorced women remarry after 5 years and 75% remarry within 10 years; these rates are even higher for women in the child-bearing years (Bramlett & Mosher, 2002). Thus, the number of families including children from one or both parents’ prior mar- riages has increased substantially. All these changes in the structure and composition of families have vast implica- tions for the understanding of child development and family life. In the following 488 n CHApTer 12 THE FAMILY sections, we will give detailed consideration to the impact of delayed parenthood, the effects of both divorce and remarriage on children’s development, and the issues surrounding maternal employment and child care. We will also consider an addi- tional change in family structure that has recently received a good deal of public attention: the increase in the number of families with lesbian or gay parents. Older Parents In 1970, 1 of 100 first births were to mothers 35 or older; in 2010, the comparable figure was more than 1 in 7 ( J. A. Martin et al., 2012). Within limits, having chil- dren at a later age has decided parenting advantages. Older first-time parents tend to have more education, higher-status occupations, and higher incomes than younger parents do. Older parents also are more likely to have planned the birth of their chil- dren and to have fewer children overall. Thus, they have more financial resources for raising a family. They are also less likely to get divorced within 10 years if they are married (Bramlett & Mosher, 2002). Older parents also tend to be more positive in their parenting of infants than younger parents are—unless they already have several children. For example, one study found that, compared with people who became parents between the ages of 18 and 25, older mothers and fathers had lower rates of observed harsh parenting with their 2-year-olds, which, in turn, predicted fewer problem behaviors a year later (Scaramella et al., 2008). In another study, this one of mothers aged 16 to 38 who had recently given birth, older moth- ers expressed greater satisfaction with parenting and commitment to the parenting role, displayed more positive emotion toward the baby, and showed greater sensitivity to the baby’s cues. However, these positive outcomes did not extend to mothers who already had two or more children. Perhaps because they had less energy to deal with so many children, these mothers tended to exhibit less positive affect and sensitive behavior with their infants than did younger mothers with two or more other children (Ragozin et al., 1982). Men who delay parenting until approximately age 30 or later are likewise more positive about the parenting role than are younger LYN W A LK E R D E N P H O T O G R A P H Y / F LI C K R / G E T T Y I M A G E S On average, older fathers engage in more verbal interactions with their preschool-aged children than do younger fathers. 1980 1985 1990 1995 2000 2005 0 20 40 60 80 100 L iv e b ir th s p er 1 ,0 0 0 u n m ar ri ed w om en i n sp ec if ic a ge g ro u p Ages 30–34 Ages 18–19 Ages 20–24 Ages 25–29 Ages 15–17 Ages 35–39 Ages 40–44 Total ages 15–44 2010 FIGURE 12.4 Birth rates for unmarried women by age of the mother The proportion of births for unmarried women in general rose sharply from 1980 to 2005. However, the rate of births for unmarried teens has dropped substan- tially since 1994, to 16.8%. (Adapted from J. A. Martin et al., 2012) C H A N G E S I N F A M I L I E S I N T H E U N I T E D S T A T E S n 489 fathers (Cooney et al., 1993; NICHD Early Child Care Research Network, 2000a). On average, they tend to be more responsive, affectionate, and cognitively and ver- bally stimulating with their infants. They are also more likely to provide a moderate amount of child care (Neville & Parke, 1997; NICHD Early Child Care Research Network, 2000a; Volling & Belsky, 1991). These differences may be partly due to older fathers’ more secure establishment in their careers, allowing them to focus on their role as father and to be more flexible in their beliefs about acceptable roles and activities for fathers (Coltrane, 1996; Parke & Buriel, 1998). Divorce In 2012, 5.4 million U.S. children lived with only their divorced mother, 1.3 mil- lion children lived only with their divorced father, and several million others lived in reconstituted families (U.S. Census Bureau, 2012). Moreover, about 40% of remarriages involving children end in divorce in 10 years (Bramlett & Mosher, 2002). Thus, the effects of divorce and remarriage on children are of great concern. The Potential Impact of Divorce Most experts agree that children of divorce are at greater risk for a variety of short- term and long-term problems than are most children who are living with both their biological parents. Compared with the majority of their peers in intact families, for example, they are more likely to experience depression and sadness, to have lower self-esteem, and to be less socially responsible and competent (Amato, 2001; Ge, Natsuaki, & Conger, 2006; Hetherington, Bridges, & Insabella, 1998). In addi- tion, children of divorce, especially boys, may be prone to higher levels of external- izing problem behaviors such as aggression and antisocial behavior, both soon after the divorce and years later (Burt et al., 2008; Hartman, Magalhães, & Mandich, 2011; Malone et al., 2004). Problems such as these may contribute to the drop in academic achievement that children of divorce often exhibit (Potter, 2010). Ado- lescents whose parents divorce exhibit a greater tendency toward dropping out of school, engaging in delinquent activities and substance abuse, and having chil- dren out of wedlock (Amato & Keith, 1991; Hetherington et al., 1998; Simons & Associates, 1996; Song, Benin, & Glick, 2012). As adults, children from divorced and remarried families are at greater risk for divorce than are their peers from intact families (Bumpass, Martin, & Sweet, 1991; Mustonen et al., 2011; Rodgers, Power, & Hope, 1997). Within this group, women, but not men, appear to also be at risk for poorer-quality intimate relationships; lower self-esteem; and lower satisfaction with social support from friends, family members, and other people (Mustonen et al., 2011). Being less likely to have completed high school or college, children of divorce often earn lower incomes in early adulthood than do their peers from intact families (Hetherington, 1999; Song et al., 2012). As adults, they are also at slightly greater risk for serious emotional disorders such as depression, anxiety, and phobias (Chase-Lansdale, Cherlin, & Kiernan, 1995). Despite all these greater risks, most children whose parents divorce do not suffer significant, enduring problems as a consequence (Amato & Keith, 1991). In fact, although divorce usually is a very painful experience for children, the differences between children from divorced families and children from intact families in terms of their psychological and social functioning are small overall (e.g., Burt et al., 2008). In addition, these differences often reflect an extension of the differences in the children’s and/or their parents’ psychological functioning that existed for years prior to the divorce (Clarke-Stewart et al., 2000; Emery & Forehand, 1994). 490 n CHApTer 12 THE FAMILY Factors Affecting the Impact of Divorce A variety of interacting factors seem to predict whether the painful experiences of divorce and remarriage will cause children significant or lasting problems. The question here is one of individual differences: Why do some children of divorce fare better than others? parental conflict One influence on children’s adjustment to divorce is the level of parental conflict prior to, during, and after the divorce (Amato, 2010; Buchanan, Maccoby, & Dornbusch, 1996). In fact, the level of parental conflict may predict the outcomes for children more than the divorce itself does. Not only is parental conflict distressing for children to observe, but it also may cause them to feel inse- cure about their own relationships with their parents, even making them fear that their parents will desert them or stop loving them (Davies & Cummings, 1994; Grych & Fincham, 1997). In addition, when there is parental conflict, fathers tend to have lower-quality relationships with their children, which may contribute to children’s adjustment problems (Pruett et al., 2003). In contrast, when parents are cooperative and communicate with each other, children exhibit fewer behavior problems and are closer with their nonresidential father (Amato, 2010). Conflict between parents often increases when the divorce is being negotiated and may continue for years after the divorce. This ongoing conflict is especially likely to have negative effects on children if they feel caught in the middle of it, as when they are forced to act as intermediaries between their parents or to inform one parent about the other’s activities. Similar pressures may arise if children feel the need to hide from one parent information about, or their loyalty to, the other parent—or if the parents inappropriately disclose to them sensitive information about the divorce and each other. Adolescents who feel that they are caught up in their divorced parents’ conflict are at increased risk for being depressed or anxious and for engaging in problematic behavior such as drinking, stealing, cheating at school, fighting, or using drugs (Afifi et al., 2007, 2008, 2009; Afifi & McManus 2010; Buchanan, Maccoby, & Dornbusch, 1991; Kenyon & Koerner, 2008). Stress A second factor that affects children’s adjustment to divorce is the stress experienced by the custodial parent and children in the new family arrange- ment. Not only must custodial parents juggle household, child-care, and financial responsibilities that usually are shared by two parents, but they often must do so isolated from those who might otherwise help. This isolation typically occurs when custodial parents have to change their residence and lose access to established social networks, or when friends and relatives— especially in-laws—take sides in the divorce and turn against them. In addition, custodial mothers usually experience a sub- stantial drop in their income, and this financial stress is often associated with problems in their physical health (Wickrama et al., 2006). Given that some of these stressors are similar to those experienced by single parents more generally, it is no surprise that the quality of parenting, as well as children’s adjustment, tends to be highest when the parents are married and the biological par- ents of the children (S. L. Brown & Rinelli, 2010; Gibson-Davis & Gassman-Pines, 2010; Magnuson & Berger, 2009). As a result of all these factors, the parenting of newly divorced mothers, compared with that of mothers in two-parent families, Divorced parents who are single often have to deal with increased levels of stress, which can affect the quality of their parenting. B R U C E A Y R E S / S T O N E / G E T T Y I M A G E S C H A N G E S I N F A M I L I E S I N T H E U N I T E D S T A T E S n 491 often tends to be characterized by more irritability and coercion and less warmth, emotional availability (e.g., parental sensitivity, structuring, nonintrusiveness, and nonhostility), consistency, and supervision of children (Hetherington, 1993; Hetherington et al., 1998; Simons & Johnson, 1996; K. E. Sutherland, Altenhofen, & Biringen, 2012). This is unfortunate because children tend to be most adjusted during and after the divorce if their custodial parent is supportive, emotionally available, and uses authoritative parenting (Altenhofen, K. E. Sutherland, & Bir- ingen, 2010; DeGarmo, 2010; Hetherington, 1993; Simons & Associates, 1996; Steinberg et al., 1991). Making parenting even more difficult for the mother, noncustodial fathers often are permissive and indulgent with their children (Hetherington, 1989; Parke & Buriel, 1998), increasing the likelihood that children will resent and resist their mother’s attempts to control their behavior. (On an optimistic note, intervention efforts among divorced mothers and children that focus on improving mother– child interactions and establishing the mother’s use of consistent discipline have been found to enhance the quality of the mother–child relationship and improve the children’s adjustment [McClain et al., 2010].) Thus, stressful life experiences during and after divorce often undermine the quality of parenting and of family interactions, which affects children’s adjustment (Ge et al., 2006). These stressful life experiences can also have a direct effect on the child’s adjustment (Figure 12.5). Having to change residences because of reduced household income, for example, may mean that at a time of high emotional vulner- ability, a child also has to go through a wrenching transition to a new home, neigh- borhood, school, and peer group (Braver, Ellman, & Fabricius, 2003; Fabricius & Braver, 2006). Disruptions such as these due to reduced family income are likely to contribute to the problems some children of divorce experience, including declines in school performance (Sun & Li, 2011). Age of the child An additional factor that influences the impact of divorce is the child’s age at the time of the divorce. Compared with older children and adoles- cents, younger children may have more trouble understanding the causes and conse- quences of divorce. They are especially more likely to be anxious about abandonment Individual characteristics of parents (e.g., personality, education, psychopathology) Stressful life experiences / economic change Child adjustment Marital transitions: divorce and remarriage Family composition Parental distress Individual characteristics of child (e.g., age, gender, temperament, intelligence) Social support Family process FIGURE 12.5 A model of the pre- dictors of children’s adjustment following divorce and remarriage Children’s adjustment to parental divorce depends on many interrelated factors. These include characteris- tics of the parents and children, fac- tors such as remarriage and economic changes, family composition (e.g., who is living in the home), the degree of social support, parental response to stressful events, and family processes that reflect these dynamics. (Adapted from Hetherington, Bridges, & Insabella, 1998) 492 n CHApTer 12 THE FAMILY by their parents and to blame themselves for the divorce (Hetherington, 1989). As an 8-year-old boy explained, a year after his parents’ divorce: My parents didn’t get along. . . . They used to argue about me all the time when they were married. I guess I caused them a lot of trouble by not wanting to go to school and all. I didn’t mean to make them argue. . . . (Wallerstein & Blakeslee, 1989, p. 73) This boy firmly believed that he caused the divorce. The following clinical report presents a picture of how divorce often affects young children: When we first saw seven-year-old Ned, he brought his family album to the office. He showed us picture after picture of himself with his father, his mother, and his little sis- ter. Smiling brightly, he said, “It’s going to be all right. It’s really going to be all right.” A year later, Ned was a sad child. His beloved father was hardly visiting and his previ- ously attentive mother was angry and depressed. Ned was doing poorly in school, was fighting on the playground, and would not talk much to his mother. (Wallerstein & Blakeslee, 1989, p. xvi) Although older children and adolescents are better able to understand a divorce than are younger children, they are nonetheless particularly at risk for problems with adjustment, including poor academic achievement and negative relationships with their parents. Adolescents who live in neighborhoods characterized by a high crime rate, poor schools, and an abundance of antisocial peers are at especially high risk (Hetherington et al., 1998), most likely because the opportunities to get into trouble are amplified when there is only one parent—who most likely is at work during the day—to monitor the child’s activity. College students are less reactive to their parents’ divorce, probably because of their maturity and relative independence from the family (Amato & Keith, 1991). With regard to their parents’ remarriage, young adolescents appear to be more negatively affected than younger children. One possible explanation for this is that young adolescents’ struggles with the issues of autonomy and sexuality are heightened by the presence of a new parent who has authority to control them and is a sexual partner of their biological parent (Hetherington, 1993; Hetherington et al., 1992). Contact with noncustodial parents Contrary to popular belief, the frequency of children’s contact with their noncustodial parent, usually the father, is not, in itself, a significant factor in their adjustment after divorce (Amato & Gilbreth, 1999; Trinder, Kellet, & Swift, 2008). Sadly, this is probably good news, because some data indicate that noncustodial fathers become increasingly uninvolved with their chil- dren over time, such that fewer than 50% of noncustodial fathers see their children more than once a year (Hetherington & Stanley- Hagan, 2002; Parke & Buriel, 1998). Moreover, it may be that the child’s adjustment after the divorce influences the father’s level of contact and involvement with the child rather than the other way around (Hawkins, Amato, & King, 2007). What does seem to affect children’s adjustment after divorce is the quality of the contact with the noncustodial father: children who have contact with competent, supportive, authoritative noncustodial fathers show better adjustment and do better in school than children who have frequent but superficial or disruptive contact with their noncustodial fathers (Amato & Gilbreth, 1999; Hetherington, 1989; TO N Y F R E E M A N / P H O T O E D IT Children of divorce benefit from interaction with noncustodial fathers only if that inter- action is of high quality. C H A N G E S I N F A M I L I E S I N T H E U N I T E D S T A T E S n 493 Hetherington et al., 1998; Whiteside & Becker, 2000). In contrast, contact with nonresidential fathers who have antisocial traits (e.g., who are vengeful, prone to getting into fights, manipulative, discourteous) predicts an increase in children’s noncompliance with their fathers (DeGarmo, 2010). Less is known about noncustodial mothers. However, it is clear that they pro- vide more emotional support for their children than noncustodial fathers do and are more likely to maintain contact through letters, phone calls, and overnight visits. The more the noncustodial mothers maintain such involvement with their children and are close to their children, the better adjusted their children are (Gunnoe & Hetherington, 2004; King, 2007). The contribution of long-standing characteristics As noted earlier, it is important to recognize that the greater frequency of problem behaviors in children in divorced and remarried families may not be solely due to the divorce and remar- riage. Rather, it sometimes may be related to characteristics of the parents or the children that existed long before the divorce. For example, the parents may have difficulty coping with stress or forming positive social relationships, as suggested by the fact that parents who divorce are more likely than undivorced parents to be depressed, alcoholic, or antisocial; to hold dysfunctional beliefs about relationships; or to lack skills for regulating conflict and negative emotion (Emery et al., 1999; Jocklin, McGue, & Lykken, 1996; Kurdek, 1993). Any one of these characteristics would be likely to undermine the quality of parenting the child receives. The idea that the greater frequency of problem behaviors in children of divorce may be related to long-standing characteristics of the children themselves is sup- ported by the finding that children of divorce tend to be more poorly adjusted prior to the divorce than are children from nondivorced families (Block, Block, & Gjerde, 1986; Hetherington & Stanley-Hagan, 2002). This difference may be due to stress in the home, poor parenting, or parental conflict prior to divorce. Alternatively or additionally, it may be due to the children’s own inherited characteristics, such as a lack of self-regulation or a predisposition to negative emotion (T. G. O’Connor et al., 2000). Such characteristics would not only underlie children’s adjustment prob- lems but, when expressed in both children and their parents, would also increase the likelihood of divorce (Hetherington et al., 1998; Jocklin et al., 1996). Children with difficult personalities and limited coping capacities may also react more ad- versely to the negative events associated with divorce than would other children. However, although heredity seems to contribute to children’s adjustment after di- vorce through its effect on children’s characteristics, heredity probably is not the most important factor in how children cope with divorce (Amato, 2010). Custody of Children After Divorce In 2009, roughly 82% of children living with one divorced parent were living with their mother (Grall, 2011). However, parents sometimes have joint custody of their children. This arrangement is generally associated with better adjustment in chil- dren than is sole custody (Bauserman, 2002), but its effects depend in part on the degree of cooperation between ex-spouses. When parents cooperate with each other and keep the children’s best interests in mind, children are unlikely to feel caught in the middle (Maccoby et al., 1993). Unfortunately, mutually helpful par- enting is not the norm (Bretherton & Page, 2004): researchers have found that once parents have been separated for a while, most either engage in conflict or do not deal much with each other (Amato, Kane, & James, 2011; Maccoby et al., 1993). 494 n CHApTer 12 THE FAMILY An Alternative to Divorce: Ongoing Marital Conflict On the basis of the publicity given to the negative effects that divorce can have on children, some people have argued that it would be better for families if it were more difficult for parents to obtain a divorce. When considering this argument, it is important to realize that sustained marital conflict has negative effects on children at all ages. Infants and children can be harmed by marital conflict because it may cause par- ents to be less warm and supportive, undermining their emo- tional involvement with the child and the security of the early parent–child attachment (El-Sheikh & Elmore-Staton, 2004; Frosch, Mangelsdorf, & McHale, 2000; Sturge-Apple et al., 2006, 2012; Taylor et al., 2008). Preschoolers and older chil- dren are especially likely to feel threatened and helpless when there is ongoing parental conflict—more so if the conflict in- volves high levels of verbal and physical aggression (Davies, Cummings, & Winter, 2004; Grych, Harold, & Miles, 2003). Even adolescents often feel threatened by, and responsible for, parental conflict (Buehler et al., 2007). Perhaps as a consequence of these negative effects, inter- parental conflict and aggression are associated with children’s and adolescents’ reduced attentional skills, negative emotion, behavioral problems, and abnormal cortisol responses to distress (Grych et al., 2004; Lindahl et al., 2004; Schermerhorn et al., 2010; Sturge-Apple et al., 2012; Towe-Goodman et al., 2011). All these outcomes are likely to be exacerbated if the sustained marital conflict leads—as it frequently does—to parental hostility toward the children themselves (Buehler et al., 1997; Harold & Conger, 1997). Further complicating matters is the fact that the relation between marital con- flict and children’s problem behavior seems to be partly due to genetic factors that affect both parents’ and children’s behavior (Harden et al., 2007; Schermerhorn et al. 2011) and partly due to the link between marital conflict and compromised par- enting behavior (Ganiban et al., 2011). Consistent with the aforementioned pat- tern of relations, Amato and colleagues (1995) found that among children raised in high-conflict families, those whose parents divorced were better adjusted than those whose parents stayed together, whereas the reverse was true for low-conflict families. Stepparenting In 2009, 5.6 million children in the United States were living with a stepparent (Kreider & Ellis, 2011). For many children, the entry of a stepparent into the fam- ily is a very threatening event. As described by one long-term study, the child’s world is suddenly full of anxious questions: What will this new man do for me? Will he threaten my position in the family? Will he interfere with my relationship with Mom and Dad? . . . Is he good for my mom? Will she be in a better mood? Will she treat me better? . . . Will my dad be angry? Will having a stepfather around make Dad want to visit me more or less? . . . Will Mom and Dad ever get remarried now that someone else is in the picture? (Wallerstein & Blakeslee, 1989, p. 246) The answers to specific questions like these obviously vary case by case. Never- theless, investigators have found some general patterns in the adjustments that are required of both children and adults when a remarriage occurs. Because ongoing marital conflict poses a variety of risks for children, the idea of staying married “for the sake of the chil- dren” may be a questionable one. IS T O C K P H O T O / T H IN K S T O C K C H A N G E S I N F A M I L I E S I N T H E U N I T E D S T A T E S n 495 Factors Affecting Children’s Adjustment in Stepfamilies Children’s adjustment to living with a stepparent is influenced by a number of factors, including the child’s age at the time of the remarriage. Very young chil- dren tend to accept stepparents more easily than do older children and adolescents (Amato & Keith, 1991; Hetherington et al., 1989). In addition, children gener- ally adjust better and do better academically when all the children are full siblings (Hetherington et al., 1999; Tillman, 2008). One indicator of this is the fact that, in adolescence, children born into blended families have higher rates of delinquency, depression, and detachment from school tasks and relationships than do full sib- lings living with their biological parents, perhaps because there may be more sibling conflict in blended families (Halpern-Meekin & Tach, 2008). The challenges in stepfamilies may differ somewhat for families with stepfathers and those with stepmothers. Although most stepfathers want their new families to thrive, they generally feel less close to their stepchildren than do fathers in intact families (Hetherington, 1993). At first, stepfathers tend to be polite and ingratiat- ing toward their stepchildren and are not as involved in monitoring or controlling them as are fathers in intact families (Kurdek & Fine, 1993). Nevertheless, on av- erage, conflict between stepfathers and stepchildren tends to be greater than that between fathers and their biological offspring (Bray & Berger, 1993; Hakvoort et al., 2011; Hetherington et al., 1992, 1999), perhaps in part because stepfathers are more likely to see the children as burdens than their biological fathers are (A. O’Connor & Boag, 2010). It is thus not surprising that children with stepfathers tend to have higher rates of depression, withdrawal, and disruptive problem behav- iors than do children in intact families (Hetherington & Stanley-Hagan, 1995). Preadolescent girls in particular are likely to have problems with their step fathers. Often the difficulty arises from the fact that prior to the remarriage, divorced moth- ers have had a close, confiding relationship with their daughters, and the entry of the stepfather into the family disrupts this relationship. These changes can lead to resentment in the daughter and conflict with both her mother and the stepfather (Hetherington et al., 1992; Hetherington & Stanley-Hagan, 2002). Despite these potential difficulties, the presence of an involved stepfather can bring benefits, including a substantial improvement in family finances and a wel- come source of emotional support and assistance for the custodial parent. A new stepfather may be especially helpful both in controlling his stepson and in provid- ing a male role model (Parke & Buriel, 1998). One sign of this is that the increase of delinquency associated with children of divorce is lessened if the adolescent’s parent remarries (Burt et al., 2008). Overall, with time, children often become as close to their stepfathers as they are to their nonresidential biological fathers, some- times even closer (Falci, 2006), usually without affecting their relationship with the biological father (King, 2009). For adolescents, having a close relationship with both their stepfather and their biological father, and believing that they matter to both, is associated with better adolescent outcomes (Schenck et al., 2009). Because there are decidedly fewer stepmothers than stepfathers, much less re- search has been devoted to their role as stepparents. However, it appears that step- mothers generally have more difficulty with their stepchildren than do stepfathers (Gosselin & David, 2007) and are at risk for depressive symptoms (D. N. Shapiro & Stewart, 2011). Often fathers expect stepmothers to take an active role in parent- ing, including monitoring and disciplining the child, although children frequently resent the stepmother’s being the disciplinarian and may reject her authority or accept it only grudgingly. This may help explain why stepmothers are more likely 496 n CHApTer 12 THE FAMILY than biological mothers to feel resentment toward their children and view them as a burden (A. O’Connor & Boag, 2010). Despite these problems, when it is pos- sible for stepmothers to use authoritative parenting successfully, stepchildren may be better adjusted (Hetherington et al., 1998). Indeed, children of both sexes are most adjusted in stepfamilies when their custodial parent is authoritative in his or her parenting style and the stepparent is warm and involved and supports the cus- todial parent’s decisions rather than trying to exert control over the children inde- pendently (Bray & Berger, 1993; Hetherington et al., 1998). An additional factor in children’s adjustment in stepfamilies is the attitude of the noncustodial biological parent toward the stepparent and the level of conflict between the two (Wallerstein & Lewis, 2007). If the noncustodial parent has hos- tile feelings toward the new stepparent and communicates these feelings to the child, the child is likely to feel caught in the middle, increasing his or her adjust- ment problems (Buchanan et al., 1991). The noncustodial parent’s hostile feel- ings may also encourage the child to behave in a hostile or distant manner with the stepparent. Not surprisingly, children in stepfamilies fare best when the relations between the noncustodial parent and the stepparent are supportive and the relations between the biological parents are cordial (Golish, 2003). Thus, the success or failure of stepfamilies is affected by the behavior and attitudes of all involved parties. Finally, the effects of restructuring the family may vary across racial and eth- nic groups. In contrast to much of the research on European American families, for example, some research on African American families suggests that there are few differences in African American youths’ depression, self-esteem, and conflict- management skills in two-parent nuclear families and in stepfamilies. Because African American children often live in a single-parent home prior to living with a stepfather, the presence of a stepfather is likely to increase positive outcomes for children (Adler-Baeder et al., 2010). Lesbian and Gay Parents Another way that U.S. families have changed in recent decades is that more lesbian and gay adults are parents. Although the numbers of lesbian and gay parents cannot be estimated with confidence because many conceal their sexual orientation, the most likely figure seems to be between 1 and 5 million ( C. J. Patterson, 2002). The 2000 Census reported that among individuals living in same-sex cohabiting partnerships, 33% of women and 22% of men had children living with them. However, because the Census survey did not ask specifically about sexual orientation, it is not clear what exactly can be inferred from these data (Cherlin, 2010). Most children of lesbian or gay parents are born when their parents are in a het- erosexual marriage or relationship. In many cases, the parents divorce when one parent comes out as lesbian or gay. In addition, an increasing number of single and coupled lesbians are choosing to give birth to children, often through the use of artificial insemination. Other lesbians or gay men choose to become foster or adop- tive parents, although there sometimes are legal barriers to such adoptions. In some cases, gay men have opportunities to act as stepfathers to the biological children of their partners (C. J. Patterson, 2002; C. J. Patterson & Chan, 1997). The question that concerns many people is whether children raised by gay and lesbian parents grow up to be different from other children. According to a grow- ing body of research, they are, in fact, very similar in their development to chil- dren of heterosexual parents in terms of adjustment, personality, and relationships C H A N G E S I N F A M I L I E S I N T H E U N I T E D S T A T E S n 497 with peers (Farr et al., 2010; Gartrell & Bos, 2010; Golombok, Spencer, & Rutter, 1983; Wainright & Patterson, 2006, 2008). They are also similar in their sexual orientation and in the degree to which their behavior is gender-typed ( J. M. Bailey et al., 1995; Fulcher, Sutfin, & Patterson, 2008; Golombok et al., 2003), as well as in their romantic involvements and sexual be- havior as adolescents (Wainright, Russell, & Patterson, 2004). Perhaps surprisingly, children of lesbian and gay parents gener- ally report low levels of stigmatization and teasing (Tasker & Golombok, 1995), although they sometimes feel excluded, or gossiped about, by peers (Bos & van Balen, 2008). This relatively low rate of difficulties with peers may be partly due to the fact that children of gay or lesbian parents frequently try to hide their parents’ sexual preference from their friends, largely because they fear being labeled by peers as gay or lesbian themselves (Bozett, 1987; Crosbie-Burnett & Helmbrecht, 1993). As in families with heterosexual parents, the adjustment of children with lesbian and gay parents seems to depend on fam- ily dynamics, including the closeness of the parent–child relationship (Wainright & Patterson, 2008), how well the parents get along, parental supportiveness, regu- lated discipline, and the degree of stress parents experience in their parenting (Farr, Forssell, & Patterson, 2010; Farr & Patterson, 2013). In addition, children of les- bian parents are better adjusted when their mother and her partner are not highly stressed (R. W. Chan, Raboy, & Patterson, 1998), when they report sharing child- care duties evenly (C. J. Patterson, 1995), and when they are satisfied with the divi- sion of labor in the home (R. W. Chan et al., 1998). When gay adoptive fathers have low levels of social support and a less positive gay identity, they experience more stress regarding parenting and are more likely to have poor relationships with their children (Tornello et al., 2011)—responses that are likely to affect their children’s adjustment. In families with a gay father and his partner, a son’s happiness with his family life is related to the inclusion of the partner in family activities and the son’s having a good relationship with the partner as well as with his biological father (Crosbie-Burnett & Helmbrecht, 1993). review: The American family has changed dramatically in recent decades. Adults are marrying later and having children later; more children are born to single mothers; and divorce and remar- riage are common occurrences. Adolescent parents come disproportionately from impoverished backgrounds and are more likely than other teens to have behavioral and academic problems. Adolescent mothers tend to be less effective parents than older mothers, and their children are at risk for behavioral and academic problems and early sexual activity. In contrast, mothers who delay childbearing tend to be more responsive to their children than are mothers who have their first children at a younger age. Parental divorce and remarriage have been associated with enduring negative outcomes, such as behavioral problems, for only a minority of children. The major factor contributing to negative outcomes for children of divorce is dysfunctional family interactions in which par- ents deal with each other in hostile ways and children feel caught in the middle. Parental depression and upset, as well as economic pressures and other types of stress associated with single parenting, often compromise the quality of parents’ interactions with each other and with their children. JA M IE C H O M A S / G E T T Y I M A G E S A growing body of research suggests that the development of children of gay and lesbian parents differs little, if at all, from that of children of heterosexual parents. 498 n CHApTer 12 THE FAMILY Stepfamilies present special challenges. Conflict is common in stepfamilies, especially when the children are adolescents, and stepparents usually are less involved with their step- children than are biological parents. Children do best if all parents are supportive and use an authoritative parenting style. An increasing number of children live in families in which at least one parent is openly lesbian or gay. There is no evidence that children raised by lesbian or gay parents are more likely to be lesbian or gay themselves or to differ from children of heterosexual parents in their adjustment. Maternal Employment and Child Care Paralleling many of the other changes that have occurred in the U. S. family over the past half century, the employment rate for mothers has increased more than fourfold. In 1955, only 18% of mothers with children younger than 6 were employed outside the home (U.S. Department of Health and Human Services, 2006). In 2011, 56% of mothers with infants younger than 1 year, 64% of mothers with children younger than 6, and 76% of mothers with children aged 6 to 17 years old worked outside the home (U.S. Department of Labor, 2013). These changes in the rates of mater- nal employment reflect a variety of factors, including greater acceptance of mothers who work outside the home, more opportunities in the workplace for women, and increased financial need, often brought about by single motherhood or divorce. The dramatic rise in the number of mothers working outside the home raised a variety of concerns. Some experts predicted that maternal employment, especially in an infant’s first year, would seriously diminish the quality of maternal caregiving and that the mother–child relationship would suffer accordingly. Others worried that “latchkey” children who were left to their own devices after school would get into serious trouble, academically and socially. Over the past two decades, much research has been devoted to addressing such concerns. For the most part, the find- ings have been reassuring. The Effects of Maternal Employment Taken as a whole, research does not support the idea that maternal employment per se has negative effects on children’s development. There is little consistent evidence, for example, that the quality of mothers’ interactions with their children necessar- ily diminishes substantially as a result of their employment (Gottfried, Gottfried, & Bathurst, 2002; Huston & Aronson, 2005; Paulson, 1996). Although working mothers typically spend less time with their children than do nonworking mothers, the difference is largely offset by the fact that, compared with nonworking moth- ers, working mothers spend a greater portion of their child-care time engaged in social interactions with their infants rather than in straightforward caregiving activities (Huston & Aronson, 2005). Even in the area of greatest debate—the effects of maternal employment on infants in their first year of life—when negative relations between maternal work and children’s cognitive or social behavior have been found, the results have not been consistent across studies, ethnic groups, or the type of analyses applied to the data (L. Berger et al., 2008; Brooks-Gunn, Han, & Waldfogel, 2010; Burchinal & Clarke-Stewart, 2007). For example, some research suggests that early maternal employment is associated with better adjustment at age 7 for children in low-in- come African American families, whereas no such effect was found for those in a study of low-income Hispanic American families (R. L. Coley & Lombardi, 2013). M A T E R N A L E M P L O Y M E N T A N D C H I L D C A R E n 499 Overall, what the evidence does suggest is that maternal employment may be associated with negative outcomes for some children under certain circumstances and that it may be associated with positive outcomes in other circumstances. As will be discussed shortly, the quality of child care provided while mothers work is undoubt- edly a critical factor affecting whether maternal employment is associated with cog- nitive, language, or social problems in young children. In addition, if children are not adequately supervised and monitored after school, their academic performance may suffer (Muller, 1995). However, if employed mothers are involved with their chil- dren and arrange for their after-school supervision, the children tend to do as well in school as children of mothers who are not employed outside the home (Beyer, 1995). Studies of maternal employment extending beyond infancy also reveal contex- tual variation in the effects that maternal employment can have on children’s devel- opment. For instance, a study of 3- to 5-year-olds found that those whose mother worked a night shift (starting at 9:00 p.m. or later) tended to exhibit more aggres- sive behavior, anxiety, and depressive symptoms than did the children whose moth- ers worked a typical daytime schedule (Dunifon et al., 2013). In another study, researchers found that mothers who worked more often at night (starting at 9:00 p.m. or later) spent less time with their adolescents, and that their adolescents had a lower-quality home environment (e.g., in terms of the quality of mother–child interactions, the cleanliness and safety of the home, and so on), which in turn pre- dicted higher levels of adolescents’ risky behaviors. These effects were especially strong for boys in low-income families. However, similar negative effects were not found in the case of mothers who worked evening shifts that ended by midnight or who had other nonstandard work schedules (e.g., those with varying hours) that allowed them greater knowledge of their children’s whereabouts (Han, Miller, & Waldfogel, 2010). There appear to be costs and benefits of maternal employment for low-income families, depending on the circumstances. Adolescents in single-parent, mother- headed families report feeling more positive emotions and higher self-esteem if their mothers are employed full time (Duckett & Richards, 1995), perhaps because maternal employment is critical for pulling mother-headed, poor families out of poverty (Harvey, 1999; Lichter & Lansdale, 1995). Nonetheless, there is also some evidence that unmarried mothers with poor-paying jobs may become less support- ive of their children and provide a less stimulating home environment after they start working, compared with when they were at home full time (Menaghan & Parcel, 1995). This drop in supportiveness is no doubt linked to the fact that single mothers with low-paying jobs are particularly likely to be stressed, unhappy with their jobs, and unable to afford services to assist them with child rearing. Maternal employment may have specific benefits for girls. Chil- dren of employed mothers are more likely than children of nonem- ployed mothers to reject the confining aspects of traditional gender roles, and they are more likely to believe that women are as compe- tent as men (L. W. Hoffman, 1984, 1989). Children of employed mothers are also more likely to be exposed to egalitarian parental roles in the family, and this experience seems to affect girls’ feelings of effectiveness (L. W. Hoffman & Youngblade, 1999). In addition, compared with peers whose mothers are not employed, daughters of employed mothers tend to have higher aspirations (Gottfried et al., 2002) and, in African American, working-class families, are more likely to stay in school (Wolfer & Moen, 1996). STE V E N R U B IN / T H E I M A G E W O R K S Some research suggests that African American daughters of working mothers are less likely to quit school than are African American daughters of mothers who are not employed. 500 n CHApTer 12 THE FAMILY The impact that maternal employment—or the lack thereof—can have on chil- dren also depends in part on how the mother is affected by her employment status (Kalil & Ziol-Guest, 2005). For example, mothers who want to work but do not are sometimes depressed (Gove & Zeiss, 1987), whereas for those who want to work and do, employment can have a positive effect on their mood and sense of effec- tiveness (L. W. Hoffman & Youngblade, 1999), which would be expected to affect the quality of their parenting (Bugental & Johnston, 2000). For many mothers, part-time work may be ideal. Recent research on mothers who were employed full-time, part-time, or not at all indicates that compared with unemployed mothers, mothers who worked part-time had fewer depressive symp- toms and better health. And compared with mothers who worked full-time, moth- ers who worked part-time showed more sensitive parenting during the preschool years, were more involved in their children’s schooling and learning in general, and their children exhibited fewer externalizing problems (Brooks-Gunn et al., 2010; Buehler & O’Brien, 2011). As already noted, a factor that is key to how maternal employment affects chil- dren’s development is the nature and quality of the day care children receive. But there, too, the effects vary as a function of the context and the individuals involved. The Effects of Child Care Because so many mothers work outside the home, a large number of infants and young children receive care on a regular basis from someone besides their parents. In the United States in 2010, 48% of children 4 years or younger with employed mothers were cared for primarily by a parent or another relative; nearly 24% were mostly in center-based child care; and 13.5% were cared for by a nonrelative in a home environment (e.g., babysitter, family day-care provider, nanny) (U.S. Depart- ment of Health and Human Services, Health Resources and Services Administra- tion, Maternal and Child Health Bureau, 2013; see Figure 12.6). In regard to the debate over potential risks and benefits of nonparental child care, some experts have argued that, especially for children from deprived back- grounds, group care, with its wide variety of activities, can provide greater cogni- tive stimulation than care at home (Consortium for Longitudinal Studies, 1983). Some have also suggested that children in group care learn important social skills through their interactions with peers (Clarke-Stewart, 1981; Volling & Feagans, Father Grandparent Other Relative Center-Based P er ce n t of C h il d re n Mother Other Nonrelative Other 30 24 18 12 6 0 FIGURE 12.6 percentage of chil- dren with employed mothers, from birth through age 4, in various types of care arrangement In 2010, 54% of children under the age of 5 (more than 11 million) had mothers who were working outside the home. More than half of these children were in care provided by nonrelatives during the hours their mother was at work (U.S. Depart- ment of Health and Human Services, 2013). M A T E R N A L E M P L O Y M E N T A N D C H I L D C A R E n 501 1995). Critics counter that enriched cognitive stimulation is provided only by high- quality child care and that much of the child care that is currently available does not provide as much stimulation as care by a parent at home does. Critics also point out that although children in child care may learn social skills from interactions with their peers, they also learn negative behaviors, such as aggression, because of the need to assert oneself in the group setting ( J. E. Bates et al., 1994; Haskins, 1985). Probably the greatest concern about child care initially was that it might under- mine the early mother–child relationship (e.g., Belsky, 1986). For example, on the basis of attachment theory (see Chapter 11, pages 428–430), it has been argued that young children who are frequently separated from their mothers are more likely to develop insecure attachments to their mothers than are children whose daily care is provided by their mothers. As you will now see, that concern is largely unwarranted. Attachment and the Parent–Child Relationship The issue of whether nonparental child care in the early years interferes with chil- dren’s attachment relationships to their parents has been examined in many stud- ies. A variety of those involving infants and preschoolers show no evidence overall that children in child care are less securely attached than other children or that they display less positive behavior in interactions with their mothers (Erel, Oberman, & Yirmiya, 2000). Other research indicates that in a small minority of cases, extensive child care is associated with negative effects on attachment, but these cases tend to involve other care-related risk factors, such as frequent turnover in outside care- givers, a high ratio of infants per caregiver, and poor-quality care at home (M. E. Lamb, 1998; Sagi et al, 2002). Similar findings have been shown in a major in-depth study funded by the National Institute of Child Health and Development (NICHD) that has followed the development of approximately 1300 children in various child-care arrangements and in elementary school. This study, begun in 1991, includes families who are from 10 locations around the United States and who vary considerably in their economic status, ethnicity, and race. The study measures (1) characteristics of the families and the child-care setting, (2) children’s attachment to, and interactions with, their mothers, and (3) their social behavior, cognitive development, and health status. E X A C T O S T O C K / S U P E R S T O C K In 2011, among children in families in pov- erty, 18% were in center-based care as their primary arrangement. In contrast, more children in families at or above the poverty line were in center-based care (Childstats, 2011). 502 n CHApTer 12 THE FAMILY A particularly important finding in this study is that how children fare in a nonma- ternal care situation is much more strongly related to characteristics of the family— such as level of income, maternal education, maternal sensitivity, and the like—than to the nature of the child care itself. Moreover, any effects, positive or negative, that child care might have on development appear to be very limited in magnitude. In- deed, insecure attachments of a notable degree were predicted only when two condi- tions existed simultaneously—that is, (1) when the children experienced poor-quality child care, had 10 or more hours of child care per week, or had more than one child- care arrangement; and (2) when their mothers were not very sensitive or responsive to them (NICHD Early Child Care Research Network, 1997a). When children were 24 and 36 months old, the quality of mother–child interac- tion was, to a slight degree, predicted by the number of hours in child care. Com- pared with mothers who did not use child care or who put their child in care for fewer hours, mothers of children who were in day care for longer hours tended to be less sensitive with their children, and their children tended to be less positive in interactions with them (NICHD Early Child Care Research Network, 1999). Even in these circumstances, the magnitudes of the effects were small. Adjustment and Social Behavior The possible effects of child care on children’s self-control, compliance, and social behavior have also been a focus of much concern and research. Here, the findings are mixed and sometimes depend on the specific mode of analysis (e.g., Crosby et al., 2010) and the country in which the research was conducted. A number of investiga- tors have found that children who are in child care do not differ in problem behavior from those reared at home (Barnes et al., 2010; Erel et al., 2000; M. E. Lamb, 1998). Indeed, in two recent large studies in Norway, a country in which the quality of child care is uniformly high, researchers found little consistent relation between amount of time in child care and children’s externalizing problems, such as aggression and noncompliance, or social competence (Solheim et al., 2013; Zachrisson et al., 2013). These findings are in notable contrast to those from the NICHD study in the United States, where the quality of child care is more variable. The NICHD study indicates that many hours a day in child care or a number of changes in caregivers in the first 2 years of life predicted lower social competence and more noncompliance with adults at age 2 (NICHD Early Child Care Research Network, 1998a). At 4½ years of age, children in extensive child care were viewed by care providers (but not by mothers) as exhibiting more problem behaviors, such as aggression, noncompliance, and anxiety/depression (NICHD Early Child Care Network, 2006). The relation be- tween more hours in center care and teacher-reported externalizing problems (e.g., aggression, defiance) was also found in the elementary school years but generally was not significant by 6th grade (Belsky et al., 2007). However, more hours of nonrela- tive care predicted greater risk taking and impulsivity at age 15 (Vandell et al., 2010). Significantly, the finding that greater time in child care is related to increased risk for adjustment problems appears not to apply to children from very low-income, high-risk families (Côté et al., 2008). In fact, longer time in child care has been found to be positively related to the better adjustment of such children, unless the quality of care is very poor (Votruba-Drzal, Coley, & Chase- Lansdale, 2004). Simi- larly, in a large study of children from high-risk families in Canada, physical aggres- sion was less common among children who were in group day care than among those who were looked after by their own families (Borge et al., 2004). High-quality child care that involves programs designed to promote children’s later success at school M A T E R N A L E M P L O Y M E N T A N D C H I L D C A R E n 503 may be especially beneficial for disadvantaged children. As in the case of Project Head Start, discussed in Chapter 8 (pages 317–320), children who experience these programs show improvements in their social competence and declines in conduct problems (Keys et al., 2013; M. E. Lamb, 1998; Peisner-Feinberg et al., 2001; Webster-Stratton, 1998; Zhai, Brooks-Gunn, & Waldfogel, 2011). Thus, it appears that most children in child care never develop significant behavior problems, but for some, the risk that they will develop such problems increases with an increase in hours spent in child care, especially center care (R. L. Coley et al., 2013). In the NICHD study, this risk was higher when children spent many hours with a large group of peers and in low-quality child care (the overall risk was modest and was not due to the characteristics of children who are put in child care for longer hours) (McCartney et al., 2010). More generally, higher-quality child care in the NICHD study was related to fewer externalizing problems in the early years (McCartney et al., 2010) and at age 15 (Vandell et al., 2010)—a relation primarily seen in children and ado- lescents who were prone to negative emotion (Belsky & Pluess, 2012; Pluess & Belsky, 2010) or who had a particular variant of gene DRD4, which, as dis- cussed in Chapter 11 (page 437), is associated with being susceptible to the effects of the environment (Belsky & Pluess, 2013). In addition, it must be remembered that the background characteristics (e.g., family income, parental education, parental personality) of children who are in day care for long hours likely differ in a variety of ways from those of children in day care for fewer hours. Therefore, cause-and-effect relations cannot be assumed, even when the effects of some of these factors are taken into account (Bolger & Scarr, 1995; NICHD Early Child Care Research Network, 1997b). Fur- thermore, the number of hours spent in child care is less relevant than the quality of child care provided: no matter what their SES background, children in high-quality child-care programs tend to be well adjusted and to develop social competencies (Love et al., 2003; NICHD Early Child Care Research Network, 2003; Votruba- Drzal et al., 2004). As noted earlier, another factor related to the effects of child care on children’s adjustment is the number of changes in the child care provided to children. In the NICHD study, increases in the number of nonparental child-care arrangements were associated with increases in children’s problem behaviors and lower levels of positive behavior such as compliance and constructive expression of emotion ( Morrissey, 2009). Instability of child care was also related to poorer adjustment in an Australian study (Love et al., 2003). Cognitive and Language Development The possible effects of child care on children’s cognitive and language performance are of particular concern to educators as well as to parents. Research suggests that high-quality child care can have a modest, positive effect on these aspects of chil- dren’s functioning (Keys et al., 2013), although the effects sometimes weaken over time (Côté et al., 2013). The NICHD study found that, overall, the num- ber of hours in child care did not correlate with cognitive or language develop- ment when demographic variables such as family income were taken into account. However, higher-quality child care that included specific efforts to stimulate chil- dren’s language development was linked to better cognitive and language devel- opment in the first 3 years of life (NICHD Early Child Care Research Network, 2000b). Children in higher-quality child care (especially center care) scored higher E LK E V A N D E V E LD E / G E T T Y I M A G E S For low-income students, some of the posi- tive academic outcomes associated with high-quality preschool child care have been found to persist into elementary grades. 504 n CHApTer 12 THE FAMILY on tests of preacademic cognitive skills, language abilities, and attention than did those in lower-quality care (NICHD Early Child Care Research Network, 2002, 2006; NICHD Early Child Care Research Network & Duncan, 2003). Higher- quality care also predicted mothers’ greater involvement in their children’s school- ing when the children were in kindergarten. This would be expected to foster chil- dren’s school performance (Crosnoe et al., 2012); promote higher vocabulary (but not reading and math) scores in elementary school (Belsky et al., 2007); and cul- tivate higher cognitive and academic achievement at age 15 (Vandell et al., 2010). Moreover, for children in high-quality care, low income was less likely to predict underachievement at 4½ to 11 years of age (Dearing et al., 2009). Other research also suggests that child care may have positive effects on cognition and that these effects are larger for higher-quality centers (Peisner-Feinberg et al., 2001). For instance, in Sweden and the United States, a number of researchers have found that children enrolled in out-of-home child care perform better on cognitive tasks, even in elementary school (Erel et al., 2000; M. E. Lamb, 1998). In addition, children from low-income families who spend long hours in child care, compared with those who spend fewer hours, tend to show increases in quantitative skills (Votruba-Drzal et al., 2004). It is likely that child care, unless it is of low quality, pro- vides greater cognitive stimulation than is available in some low-income homes. Quality of Child Care It is not surprising that the quality of child care children receive outside the home is related to some aspects of their development. Unfortunately, most child-care centers in the United States do not meet the recommended minimal standards established by such organizations as the American Academy of Pediatrics and the American Public Health Association. These minimum standards include: n A child-to-caregiver ratio of 3:1 for children aged 12 months or less; 4:1 for 13- to 35-month-olds; 7:1 for 3-year-olds; and 8:1 for 4-and 5-year-olds n Maximum group sizes of 6 for 12-months-olds and younger; 8 for 13- to 35-month-olds; 14 for 3-year-olds; and 16 for 4- and 5-year-olds n Formal training for caregivers, with lead teachers having (1) a bachelor’s degree in early childhood education, school-age care, child development, social work, nursing, or other child-related field, or an associate’s degree in early childhood education and currently working toward a bachelor’s degree; (2) at least one year of on-the-job training in providing a nurturing environment and meeting children’s out-of-home needs (American Academy of Pediatrics et al., 2011). For child-care facilities in homes, the recommended minimum standards are more stringent; for example, the child–caregiver ratios are 2:1 for children 23 months and younger, 3:1 for 24- to 35-month-olds, 7:1 for 4-year-olds, and 8:1 for 5-year-olds, with maximum group size of 6, 8, 12, and 12 for these age groups, respectively. In the NICHD study, children in a form of day care that met more of these guidelines tended to score higher on tests of language comprehension and readiness for school, and they had fewer behavior problems at age 36 months. The more stan- dards that were met, the better the children performed at 3 years of age (NICHD Early Child Care Research Network, 1998b). (See Table 12.1 for quality standards set by an early-education association for quality child care.) Quality was generally highest in nonprofit centers that were not religiously affiliated; intermediate in nonprofit religiously affiliated centers and in for-profit independent centers; and lowest in for-profit chains (Sosinsky, Lord, & Zigler, 2007). M A T E R N A L E M P L O Y M E N T A N D C H I L D C A R E n 505 TABLE 12.1 Characteristics of Good Child-Care programs Experts in early-childhood education recommend that parents assess child-care programs before selecting one for their children. Following are some of the indicators of high-quality child care, set forth by the National Association for the Education of Young Children (1986), that parents should look for. (Note that the standards discussed on the preceding page are even more stringent than the standards of this professional association.) Characteristics of the Staff 1. The adults caring for children enjoy observing and understand how young children learn and grow. They are considerate to children, and their expectations vary according to children’s ages and interests. Staff also continue to learn about young children through conferences and other forms of education. 2. The staff continually foster children’s emotional and social development. They listen and talk to the children; are consistent and gentle, yet firm, in discipline; help children learn to consider others’ feelings and rights; and assist them in learning how to deal with negative emotions constructively. 3. There are enough adults available to work with groups of children and to meet their individual needs. For infants, there should be no more than eight children in the care of at least two adults. Two- and three-year-olds should be in groups of no more than 16, with two adults. Four- and five- year-olds should be in groups of no more than 20 children, with at least two adults. 4. All staff members work together cooperatively. They meet regularly to plan and evaluate the child- care program, and they will adjust daily activities to accommodate children’s individual needs and interests. 5. The staff observe and keep records of each child’s progress and development. They stress children’s accomplishments, use their records to educate parents, and are responsive to parents’ concerns about their child’s progress. Program Activities and Equipment 1. The environment fosters children’s working and playing together. Staff provide opportunities for both vigorous outdoor play and quiet indoor play, for children to select their own activities, and for children to work alone as well as in small groups. Children also are encouraged to develop self-help skills when they are ready. 2. A quality program provides a wide range of activities and appropriate materials—climbing equipment, blocks, balls, dramatic-play props, art supplies, puzzles, small manipulatable toys, books, and plants or animals and other natural science objects for children to care for or observe. In addition, there are opportunities for activities involving music and movement, such as dance. 3. Children are assisted in increasing their language skills and their understanding of the world. They talk freely among themselves and with adults, and staff talk with children about objects, feelings, experiences, and events. Children are encouraged to solve their own problems and to think independently. Field trips enhance children’s learning experiences. 4. The health of the children, staff, and parents is promoted and protected. The staff are alert to health issues—for example, with regard to food, room temperature, and cleanliness—and medical records and emergency information are kept for each child. 5. The facility is safe for children and staff; for example, the facility is free of hazards, toxic materials are locked away, and indoor and outdoor surfaces are cushioned with materials such as carpeting or wood chips. 6. The environment is large enough to allow a variety of activities and equipment. There should be at least 35 square feet of usable playroom floor space indoors per child and 75 square feet of play space outdoors for each child. There is also space for adults to walk between sleeping children’s cots and for children’s personal items. Staff Relations with the Community 1. A good program considers and supports the needs of entire families. Parents are welcome to observe the children, discuss policies, and participate in center activities. Staff members share highlights of a child’s experiences with parents and are alert to family matters that might affect a child. The staff also respect family members from diverse cultures and backgrounds. 2. Staff are aware of, and contribute to, community resources. For example, they refer family members to appropriate services when needed, share information on community recreational and educational opportunities, and collaborate with other professional groups to provide high-quality child care. 3. Good centers encourage parents who are interested in their programs to observe and ask questions about the facilities, staff, and program philosophy and activities. If staff are not open about these matters, it is likely that the facility does not provide optimal care. 506 n CHApTer 12 THE FAMILY review: The bulk of recent research on maternal employment indicates that it often benefits chil- dren and mothers and that it has few negative effects on children if they are in child care of acceptable quality and are supervised and monitored. Unfortunately, however, in low-income families, especially those headed by a single parent, adequate child care and supervision may not always be possible. Because so many mothers work, a large proportion of children receive some care from adults other than their parents. Recent research on child care indicates that, on the whole, nonmaternal care has small, if any, effect on the quality of the mother–child relation- ship. Children who spend long hours in centers tend to exhibit more aggressive behavior at schools, but the effects are modest and likely are nonsignificant for high-quality child care. High-quality care does appear to have some modest benefits for cognitive development and especially language development. Whether child care has positive or negative effects on chil- dren’s functioning probably depends on the characteristics of the child, the number of hours in care, the quality of parenting at home, and the quality of the care situation. chapter summary: Family Dynamics n How well a family fulfills its functions depends on its family dynamics: all the family members influence one another, and the nature of their interactions shapes children’s development. The Role of Parental Socialization n Parents socialize their children’s development through direct instruction; through their modeling of skills, attitudes, and behavior; and through their managing of children’s experiences and social lives. n Researchers have identified several types of parenting styles related to the dimensions of warmth and control. Authori- tative parents are supportive and relatively high in control; their children tend to be socially and academically competent. Authoritarian parents are low in warmth and high in control; their children tend to be relatively low in social and academic competence, unhappy, and low in self-confidence. Permissive parents are responsive to their children’s needs and wishes and low on control; their children tend to be low in self-control and in school achievement. Rejecting-neglecting parents are low in demandingness, support, and control; their chil- dren tend to have disturbed attachment relationships during infancy, poor peer relations during childhood, and poor adjust- ment in adolescence. n The significance and effects of different parenting styles or practices may vary somewhat across cultures. n Parenting styles and practices are affected by characteristics of the children, including their attractiveness, behavior, and temperament. n Parents’ beliefs and values tend to differ across social classes, such that lower socioeconomic status tends to be associated with authoritarian parenting. n Economic stressors can undermine the quality of marital and parent–child interactions, increasing children’s risk for depression, academic failure, disruptive behavior, and drug use. n Homeless children are more likely than other children to show delays in cognitive and language development, to have academic difficulties, and to show problems in adjustment. Mothers, Fathers, and Siblings n Mothers typically interact with their children much more than fathers do, and fathers’ play tends to be more physical than mothers’ play. However, the nature of parent–child interactions differs across cultures. n Siblings learn from one another, can be sources of support for one another, and sometimes engage in conflict. Siblings get along better if they have good relationships with their parents and if one of them does not feel that their parents treat him or her less well than they treat his or her siblings. Changes in Families in the United States n In the United States today, adults are marrying later, more children are being born to single mothers, and divorce and remarriage are common occurrences. C H A P T E R S U M M A R Y n 507 chapter summary: n Adolescent parents come disproportionately from impover- ished backgrounds and families with cold, uninvolved parents. Adolescent mothers tend to be less effective parents than older parents, and their children are at risk for behavioral and aca- demic problems, delinquency, and early sexual activity. Children of adolescent mothers fare better if their mothers have more knowledge about parenting and if the children themselves have a warm, involved relationship with their fathers. n Mothers who delay childbearing tend to be more responsive with their children and to enjoy motherhood more than do mothers who have their first children in their teens and 20s. n Parental divorce and remarriage have been associated with enduring negative outcomes such as behavioral problems for a minority of children. The major factor contributing to negative outcomes for children of divorce is hostile, dysfunctional family interactions, including continuing conflict between ex-spouses. n Parental depression and upset, as well as other types of stress associated with single parenting, often compromise the quality of divorced parents’ interactions with their children. n Conflict is common in stepfamilies. Children often are hostile toward stepparents, and stepparents usually are less involved with their stepchildren than are biological parents. Children do best if all parents are supportive and use an authoritative parenting style. n There is no evidence that children raised by lesbian or gay par- ents differ from children of heterosexual parents in their sexual orientation or adjustment. Maternal Employment and Child Care n Children and mothers reap some benefits from maternal employment, and maternal employment has few negative effects on children if they are in child care of acceptable quality and are supervised and monitored by adults. n Experience with nonmaternal care has small negative effects on the quality of the mother–child relationship for some young children, especially if they are in child care for long hours, the quality of care is low, and their mother is insensitive. n Child care is associated with a small increase in negative problem behavior for children from working- and middle-class families, especially if they are not in a high-quality program, but it may be associated with improvements in adjustment for low-income children. n Children in high-quality care do better in their cognitive and language development than children in low-quality care. Whether child care has positive or negative effects on chil- dren’s functioning probably depends in part on the characteris- tics of the child, the child’s relationship with his or her mother, and the quality of the child-care situation. Critical Thinking Questions 1. It often is assumed that parental socialization of children’s behavior is a bidirectional process, with the parent affecting the child’s behavior and the child’s behavior also evoking some socialization practices or behaviors. Provide examples of bidirectional causality in regard to (a) the relation between parental punitive practices and children’s aggression, and (b) the relation between parental use of punitive control and children’s self-regulation. 2. In some cultures, respect for authority, including the authority of parents in general, is valued more than in many Western industrialized countries. How might this cultural variation affect interactions between parents and children and the relation of parenting styles to children’s social and emotional development? Similarly, how might living in a cul- ture in which men and women often are separated (e.g., do not eat together) and women are discouraged from going out in public affect parent–child relationships and interactions? 3. Think about the ways your parents interacted with you when you were a child. Based on Baumrind’s categories of par- enting style, which type of parenting did your mother and/or father display? What specific behaviors did you use to classify their parenting? 4. Make a list of the advantages and disadvantages of joint cus- tody for children of divorce. How would the advantages and disadvantages vary for families in which the parents either (a) argue a lot or get along and (b) live 50 miles apart or 5 miles apart after the divorce? 5. What factors might make it difficult to study children’s development in families with gay or lesbian parents? Key Terms authoritarian parenting, p. 474 authoritative parenting, p. 473 bidirectionality of parent–child interactions, p. 478 family dynamics, p. 470 parenting styles, p. 472 permissive parenting, p. 474 rejecting-neglecting parenting, p. 474 508 P R IV AT E C O LL E C T IO N / T H E B R ID G E M A N A R T L IB R A R Y KO M I C H E N , Show Off, 1994 (gouache on silk) 509 Peer Relationships n What Is Special About Peer Relationships? n Friendships Early Peer Interactions and Friendships Developmental Changes in Friendship The Functions of Friendships Effects of Friendships on Psychological Functioning and Behavior over Time Children’s Choice of Friends Box 13.1: Individual Differences Culture and Children’s Peer Experience Review n Peers in Groups The Nature of Young Children’s Groups Cliques and Social Networks in Middle Childhood and Early Adolescence Cliques and Social Networks in Adolescence Box 13.2: A Closer Look Cyberspace and Children’s Peer Experience Negative Influences of Cliques and Social Networks Romantic Relationships with Peers Review n Status in the Peer Group Measurement of Peer Status Characteristics Associated with Sociometric Status Box 13.3: Applications Fostering Children’s Peer Acceptance Stability of Sociometric Status Cross-Cultural Similarities and Differences in Factors Related to Peer Status Peer Status as a Predictor of Risk Review n The Role of Parents in Children’s Peer Relationships Relations Between Attachment and Competence with Peers Quality of Ongoing Parent–Child Interactions and Peer Relationships Parental Beliefs Gatekeeping and Coaching Family Stress and Children’s Social Competence Review n Chapter Summary chapter 13: 510 I n Chapters 1 and 11, we described the plight of institutionalized orphans who, lacking consistent interaction with a caring adult, developed social, emotional, and cognitive deficits. After World War II, an interesting exception to this pat- tern was noted by Anna Freud—the daughter of Sigmund Freud—and Sophie Dann (1951/1972). They observed six young German-Jewish children who had been victims of the Hitler regime. Soon after these children were born, their parents were deported to Poland and killed. The children were subsequently moved from one refuge to another until, between the ages of approximately 6 and 12 months, they were placed in a ward for motherless children in a concentration camp. The care they received in this ward was undoubtedly compromised by the fact that their caregivers were themselves prisoners who were undernourished and overworked. Moreover, the rates of deportation and death among the prisoners were high, so it is likely that the children’s caregivers changed frequently. In 1945, approximately 2 to 3 years after the children’s arrival at the concentra- tion camp, the camp was liberated; within a month, the six children were sent to Britain. After spending 2 months in a reception facility, the children, as a group, were sent to various shelters and then, finally, to a country house that had been con- verted to accommodate orphans. Given the conditions of their early lives, it is not surprising that these children initially showed a variety of problem behaviors in their new home: During the first days after arrival they destroyed all the toys and damaged much of the furniture. Toward the staff they behaved either with cold indifference or with ac- tive hostility, making no exception for the young assistant Maureen who had accom- panied them from Windermere and was their only link with the immediate past. At times they ignored the adults so completely that they would not look up when one of them entered the room. . . . In anger, they would hit the adults, bite or spit . . . shout, scream, and use bad language. (A. Freud & Dann, 1972, p. 452) These children behaved quite differently among themselves, however. They obviously were deeply attached to one another, sensitive to one another’s feel- ings, and they exhibited almost a complete lack of envy, jealousy, and rivalry. They shared possessions and food, helped and protected one another, and admired one another’s abilities and accomplishments. The children’s closeness is reflected in this brief selection from Freud and Dann’s daily observations: November 1945—John cries when there is no cake left for a second helping for him. Ruth and Miriam offer him what is left of their portions. While John eats their pieces of cake, they pet him and comment contentedly on what they have given him. . . . December 1945—Paul loses his gloves during a walk. John gives him his own gloves, and never complains that his hands are cold. . . . April 1946—On the beach in Brighton, Ruth throws pebbles into the water. Peter is afraid of the waves and does not dare to approach them. In spite of his fear, he sud- denly rushes to Ruth, calls out: “Water coming, water coming,” and drags her back to safety. . . . Freud and Dann concluded that the children, although aggressive and difficult for adults to handle, were “neither deficient, delinquent nor psychotic” (p. 473) and that their relationships with one another helped them to master their anxiety and develop the capacity for social relationships. Themes n Nature and Nurture n The Active Child n Continuity/Discontinuity n The Sociocultural Context n Individual Differences n Research and Children’s Welfare n 511P E E R R E L A T I O N S H I P S n 511 Freud and Dann’s observations provided some of the first evidence that relationships with peers can help very young children develop some of the social and emotional capacities that usually emerge in the context of adult–child attachments. Two decades later, similar findings were obtained in research with monkeys. As discussed in Chapter 10, Stephen Suomi and Harry Harlow raised laboratory mon- keys in isolation from other monkeys from birth to 6 months of age. By the end of this period, the iso- late monkeys had developed significant abnormali- ties in behavior, such as compulsive rocking and a reluctance to explore. Some of the isolate monkeys were subsequently placed with one or two normal, playful monkeys who were 3 months younger. Over the course of the next several months, the isolate monkeys’ abnormal behaviors diminished greatly, and they began to explore their environment and engage in social interactions, demonstrating that peers can provide some of the social and emotional experiences required for normal development in monkeys (Suomi & Harlow, 1972). Findings such as these do not suggest that peers alone can produce optimal development in young children. However, they do suggest that peers can contribute to children’s development in meaningful ways. In fact, in Western societies, chil- dren’s relationships with other children—their friends and acquaintances at school and in the neighborhood—usually play a very important role in their lives. By mid- dle childhood in the United States, for example, more than 30% of children’s social interactions involve peers (Rubin, Bukowski, & Parker, 1998). As they grow older, children spend increasingly more time with peers and interact with a greater num- ber of them. Thus, peer interactions are a context in which children develop social skills and test new behaviors, good and bad. In this chapter, we consider the special nature of peer interactions and their implications for children’s social development. First, we discuss theoretical views on what makes peer interactions special. Then we look at friendships, the most inti- mate form of peer relationships, and consider questions such as: How do children’s interactions with friends differ from those with other peers (nonfriends)? How do friendships change with age? What do children get out of friendships and how do they think about them? Next, we consider children’s relationships in the larger peer group. These relationships are discussed separately from friendships because they appear to play a somewhat different role in children’s development, particularly in regard to the provision of intimacy. We try to answer questions such as: What are the differences among children who are liked, disliked, or not noticed by their peers? Does chil- dren’s acceptance or rejection by peers have long-term implications for their behav- ior and psychological adjustment? In our discussions of friendships as well as more general peer relationships, we will examine individual differences among children in their relationships with peers and the ways in which these differences may cause differences in development. In addition, we will focus on the influence that the sociocultural context has on peer relationships, the contributions that both nature and nurture make to the quality of Anna Freud’s study of children who lived together in a concentration camp provided evidence of the importance of early peer relationships. B E T T M A N N / C O R B IS 512 n chApter 13 PEER RELATIONSHIPS children’s peer relationships, and the role of the active child in choosing friends and activities with peers. We will also consider the question of whether changes in chil- dren’s thinking about friendships exhibit continuity or discontinuity. Finally, as an example of research and children’s welfare, we will examine interventions to improve children’s interactions with other children. What Is Special About Peer Relationships? Many theorists have argued that peer relationships provide special opportunities for children’s development. To begin with, peers are, by definition, individuals who are close in age to one another, closer usually than siblings. Thus, in contrast to their status in most of their other relationships, especially those with adults, children are relatively equal in terms of power when they interact with their peers (Furman & Buhrmester, 1985). Piaget (1932/1965) suggested that because of this relative equality, children tend to be more open and spontaneous with peers when expressing their ideas and beliefs than they are with adults. As Piaget noted, children often accept adults’ beliefs and rules on the basis of mere obedience rather than on the basis of understanding or agreement (Youniss, 1980). With peers, on the other hand, children are more likely to openly criticize another’s ideas, clarify and elaborate their own ideas, and ask for feedback (A. C. Kruger & Tomasello, 1986). In this way, peers jointly construct their own explanations and rules for why or how things work or should work. Similarly, Vygotsky (1978) suggested that children learn new skills and develop their cognitive capacities in peer interactions. However, unlike Piaget, Vygotsky highlighted the role of cooperation between peers. In particular, he emphasized the ways in which children’s working together helps to build new skills and abilities, as well as to convey the knowledge and skills valued by the culture. Other researchers have emphasized the social and emotional gains provided by peer interaction. In the preschool and school years, peers are an important source of companionship and assistance with problems and tasks (Youniss, 1980). As children R O B IN S A C H S / P H O T O E D IT Both disagreement and cooperation within the context of peer relationships have been emphasized by theorists as important con- tributors to children’s cognitive develop- ment. even something as seemingly simple as establishing the ground rules for an informal game of softball can hone chil- dren’s skills in debate and compromise. peers n people of approximately the same age and status F R I E N D S H I P S n 513 become older, peers may become more important as a source of emotional support and provide children with their first experience of an intimate interpersonal relation- ship based on reciprocity and exchange between equals (H.S. Sullivan, 1953). In summary, theorists such as Piaget, Vygotsky, and others have argued that peer relationships provide a unique context for cognitive, social, and emotional devel- opment. In their view, the equality, reciprocity, cooperation, and intimacy that can develop in peer relationships, especially friendships, enhance children’s reasoning ability and their concern for others. In the next section, we will focus particularly on what friendships are like, how they change with age, and what possible benefits and costs they carry with them. Friendships Kay and Sarah are my best friends—we talk and share secret things . . . and we some- times do things with Jo and Kerry and Sue. Then there’s all the rest of the girls— some are nice. But the boys—yuk! (Annie, aged 8, cited by Dunn, personal communication, 1999) Annie, the speaker above, clearly differentiates her close friends from other chil- dren she knows and with whom she may also interact. Researchers generally agree that friends are people who like to spend time together and feel affection for one another. In addition, their interactions are characterized by reciprocities; that is, friends have mutual regard for one another, exhibit give-and-take in their behavior (such as cooperation and negotiation), and benefit in comparable ways from their social exchanges (Bukowski, Newcomb, & Hartup, 1996). In brief, a friendship is an intimate, reciprocated positive relationship between two people. As we will dis- cuss next, the degree to which the conditions of friendship become evident in peer interactions increases with age during childhood. Early Peer Interactions and Friendships Very young children usually cannot verbally indicate who they like, so researchers must make inferences about children’s friendships from observing their behavior with peers. In doing so, researchers have focused particularly on such issues as the age at which friendships first develop, the nature of early friend- ships, and age-related changes in friendships. friendship n an intimate, reciprocated positive relationship between two people Some researchers believe that friendships may begin at 2 years of age or even earlier. E LI Z A B E T H C R E W S Do Very Young Children Have Friends? Some investigators have argued that children can have friends by or before the age of 2 (C. Howes, 1996). Consider the following example: Anna and Suzanne are not yet 2 years old. Their mothers became acquainted during their pregnancies and from their earliest weeks of life the little girls have visited each other’s houses. When the girls were 5 months old they were enrolled in the same child-care center. They now are frequent play partners, and sometimes in- sist that their naptime cots be placed side by side. Their greetings and play are often marked by shared smiles. Anna and Suzanne’s parents and teachers identify them as friends. (C. Howes, 1996, p. 66) 514 n chApter 13 PEER RELATIONSHIPS Even 12- to 18-month-olds seem to select and prefer some children over oth- ers, touching them, smiling at them, and engaging in positive interactions with them more than they do with other peers (D. F. Hay, Caplan, & Nash, 2009; C. Howes, 1983; Shin, 2010). In addition, when a preferred peer shows distress, tod- dlers are three times more likely to respond by offering comfort or by alerting an adult than they are when a nonpreferred peer is upset (C. Howes & Farver, 1987). Starting at around 20 months of age, children also increasingly initiate more in- teractions with some children than with others and contribute more when play- ing games with those children (H. S. Ross & Lollis, 1989). By age 3 or 4, children can make and maintain friendships with peers (Dunn, 2004), and most have at least one friendship (M. Quinn & Hennessy, 2010). By age 3 to 7 years, it is not uncommon for children to have “best friends” who retain that status over at least several months’ time (Sebanc et al., 2007). Differences in Young Children’s Interactions with Friends and Nonfriends By the age of 2, children begin to develop several skills that allow greater com- plexity in their social interactions, including imitating peers’ and other people’s social behavior (Seehagen & Herbert, 2011), engaging in cooperative problem solving, and trading roles during play (C. A. Brownell, Ramani, & Zerwas, 2006; C. Howes, 1996; C. Howes & Matheson, 1992). These more complex skills tend to be in greater evidence in the play of friends than of nonfriends (acquaintances) (Werebe & Baudonniere, 1991). Especially with friends, cooperation and coordination in children’s interac- tions continue to increase substantially from the toddler to the preschool years (C. Howes & Phillipsen, 1998). This is especially evident in shared pretend play (Dunn, 2004), which occurs more often among friends than among nonfriends (C. Howes & Unger, 1989). As discussed in Chapter 7, pretend play involves symbolic actions that must be mutually understood by the play partners, as in the following example: Johnny, 30 months, joins his friend Kevin who is pretending to go on a picnic. Johnny, on instruction from 3-year-old Kevin, fills the car with gas, “drives” the car, then gets the food out, pretends to eat it, saying he doesn’t like it! Both boys pretend to spit out the food, saying “yuk!,” laughing. . . . (Dunn, personal communication, 1999) Pretend play may occur more often among friends because friends’ experiences with one another allow them to trust that their partner will work to interpret and share the meaning of symbolic actions (C. Howes, 1996). The degree to which preschoolers engage in, and are competent at, such pretend play is related to their prosocial behaviors such as kindness, cooperation, sharing, and empathy (Spivak & Howes, 2011). While the rate of cooperation and positive interactions among young friends is higher than among nonfriends, so is the rate of conflict. Preschool friends quarrel as much or more with one another as do nonfriends and also more often express hos- tility by means of assaults, threats, and refusing requests (Fabes et al., 1996; D. C. French et al., 2005; Hartup et al., 1988). The higher rate of conflict for friends is likely due, in part, to the greater amount of time friends spend together. Although preschool friends are more likely than nonfriends to fight, they also are more likely to resolve conflicts in controlled ways, such as by negotiating, asserting F R I E N D S H I P S n 515 themselves nonaggressively, acquiescing, or simply ceasing the activity that is causing the conflict (Fabes et al., 1996; Hartup et al., 1988) (see Table 13.1). Moreover, friends are more likely than nonfriends to resolve conflicts in ways that result in equal outcomes rather than in one child’s winning and another’s losing. Thus, after a conflict, friends are more likely than nonfriends to resume their interactions and to have positive feelings for one another. Developmental Changes in Friendship In the school years, many of the patterns apparent in the interac- tions among preschool-aged friends and nonfriends persist and become more sharply defined. As earlier, friends, in comparison with nonfriends, communicate more and better with one another and cooperate and work together more effectively (Hartup, 1996). They also fight more often—but again, they are also more likely to negotiate their way out of the conflict (Laursen, Finkelstein, & Betts, 2001). In addition, they now have the maturity to take re- sponsibility for the conflict and to give reasons for their disagreement, increasing the likelihood of their maintaining the friendship (Fonzi et al., 1997; Hartup et al., 1993; Whitesell & Harter, 1996). Although children’s friendships remain similar in many aspects as the children grow older, they do change in one important dimension: the level and impor- tance of intimacy. The change is reflected both in the nature of friends’ interac- tions with one another and in the way children conceive of friendship. Between ages 6 and 8, for example, children define friendship primarily on the basis of actual activities with their peers and tend to define “best” friends as peers with whom they play all the time and share everything (Gummerum & Keller, 2008; Youniss, 1980). At this age, children also tend to view friends in terms of rewards and costs (Bigelow, 1977). In this respect, friends tend to be close by, have inter- esting toys, and have similar expectations about play activities. Nonfriends tend to be uninteresting or difficult to get along with. Thus, in the early school years, children’s views of friendship are instrumental and concrete (Rubin, Bukowski, & Parker, 2006) (see Table 13.2). In contrast, between the early school years and adolescence, children in both Asian and Western countries increasingly define their friendships in terms of char- acteristics such as companionship, similarity in attitudes/interests, acceptance, trust, genuineness, mutual admiration, and loyalty (Furman & Buhrmester, 1992; Gummerum & Keller, 2008; McDougall & Hymel, 2007). At about 9 years of age, children seem to become more sensitive to the needs of others and to the inequali- ties among people. Children define friends in terms of taking care of one another’s physical and material needs, providing general assistance and help with school work, reducing loneliness and the sense of being excluded, and sharing feelings. The following descriptions of friends are typical: female, 10: If you’re hurt, they come over and visit. male, 9: Help someone out. If the person is stuck, show them the answer but tell them why it’s the answer. male, 9: You’re lonely and your friend on a bike joins you. You feel a lot better because he joined you. (Youniss, 1980, pp. 177–178) TABLE 13.1 Strategies chosen by Schoolchildren When a peer Says Something Mean to, or About, them Percent of Children Selecting Each Strategy When the Peer Is: Their Best Friend Classmate (Neither a Friend nor Enemy) Talk to friend/classmate 43% 19% Think about what to do 24% 14% Hit, kick, yell 9% 10% Hold anger in 8% 5% Quit thinking about it 6% 20% Get away from what happened 4% 17% Talk to someone else about it 4% 11% Do nothing 1% 4% Adapted from Whitesell & Harter, 1996 TABLE 13.2 Dimensions on Which elementary School children Often evaluate their Friendships Validation and Caring Makes me feel good about my ideas. Tells me I am good at things. Conflict Resolution Make up easily when we have a fight. Talk about how to get over being mad at each other. Conflict and Betrayal Argue a lot. Doesn’t listen to me. Help and Guidance Help each other with school work a lot. Loan each other things all the time. Companionship and Recreation Always sit together at lunch. Do fun things together a lot. Intimate Exchange Always tell each other our problems. Tell each other secrets. Adapted from Parker & Asher, 1993 516 n chApter 13 PEER RELATIONSHIPS When children are about 10 years old, loyalty, mutual understanding, and self- disclosure become important components of children’s conceptions of friend- ship (Bigelow, 1977). In addition, both preadolescents and adolescents emphasize cooperative reciprocity (doing the same things for one another), equality, and trust between friends (Youniss, 1980). The following descriptions are indicative of how children in this age range view their friends: female, 10: Somebody you can keep your secrets with together. Two people who are really good to each other. male, 12: A person you can trust and confide in. Tell them what you feel and you can be yourself with them. female, 13: They’ll understand your problems. They won’t always be the boss. Some- times they’ll let you decide; they’ll take turns. If you did something wrong, they’ll share the responsibility. male, 14: They have something in common. You hang around with him. . . . We’re more or less the same; the same personalities. (Youniss, 1980, pp. 180–182) More than younger children, adolescents use friendship as a context for self- exploration and working out personal problems (Gottman & Mettetal, 1986). Thus, friendships become an increasing source of intimacy and disclosure with age, as well as a source of honest feedback. These changes may explain why adolescents perceive the quality of their friendships as improving from middle to late adoles- cence and why they value them so highly (Way & Greene, 2006). What accounts for the various age-related changes that occur in children’s friendships, particularly with regard to their concept of friendship? Some researchers have argued that the changes in children’s thinking about friend- ship are qualitative, or discontinuous. For example, Selman (1980) suggested that changes in children’s reasoning about friendships are a consequence of age-related qualitative changes in their ability to take others’ perspectives (see Chapter 9, page 357). In the view of Selman, as well as of Piaget and others, young children have limited awareness that others may feel or think about things differently than During the elementary school years, the willingness to lend support and help, including with homework, becomes an important dimension of friendship. R O B L E W IN E / T E T R A I M A G E S / C O R B IS B U B B LE S P H O T O LI B R A R Y / A LA M Y Adolescent friends are more likely to share confidences with one another than are younger friends. F R I E N D S H I P S n 517 they themselves do. Consequently, their thinking about friendships is limited in the degree to which they consider issues beyond their own needs. As children begin to understand others’ thoughts and feelings, they realize that friendships involve consideration of both parties’ needs so that the relationship is mutually satisfying. Other researchers argue that the age-related changes in children’s conceptions of friendships reflect differences in how children think and express their ideas rather than age-related differences in the basic way they view friendships. Hartup and Stevens (1997) maintain that children of all ages consider their friendships “to be marked by reciprocity and mutuality—the giving and taking, and returning in kind or degree” (p. 356). What differs with age is merely the complexity with which chil- dren view friendship and describe its dimensions. Nonetheless, these differences likely have important effects on children’s behavior with friends and on their reac- tions to friends’ behavior. For example, because 6th-graders are more likely than 2nd-graders to report that intimacy and support are important features of friend- ships (Furman & Bierman, 1984), they are more likely to evaluate their own and their friends’ behaviors in terms of these dimensions. The Functions of Friendships As is clear from their statements about the meaning of friendships, having friends provides numerous potential benefits for children. The most important of these, noted by Piaget, Vygotsky, and others, are emotional support and the validation of one’s own thoughts, feelings, and worth, as well as opportunities for the develop- ment of important social and cognitive skills. Support and Validation Friends can provide a source of emotional support and security, even at an early age. Consider the following fantasy play interaction between Eric and Naomi, two 4-year-olds who have been best friends for some time. In the course of their play, Eric expresses his ongoing fear that other children don’t like him and think he’s stupid: Eric: I’m the skeleton! Whoa! [screams] A skeleton, everyone! A skeleton! Naomi: I’m our friend, the dinosaur. Eric: Oh, hi Dinosaur. [subdued] You know, no one likes me. Naomi: [reassuringly] But I like you. I’m your friend. Eric: But none of my other friends like me. They don’t like my new suit. They don’t like my skeleton suit. It’s really just me. They think I’m a dumb-dumb. Naomi: I know what. He’s a good skeleton. Eric: [yelling] I am not a dumb-dumb! Naomi: I’m not calling you a dumb-dumb. I’m calling you a friendly skeleton. (Parker & Gottman, 1989, p. 95) In this fantasy play situation, Naomi clearly served as a source of support and validation for Eric. When he expressed concern that others do not like him, she reassured him that she does. And when he confessed that the other children think he, not the skeleton, is dumb, she shifted the focus from him to the fantasy skel- eton character, praising the skeleton character to make Eric feel competent (“He’s a good skeleton”) (Gottman, 1986). 518 n chApter 13 PEER RELATIONSHIPS Friends also can provide support when a child feels lonely. School-aged children with best friends and with intimate, supportive friendships experience less loneli- ness compared with children who do not have a best friend or whose friends are less caring and intimate (Asher & Paquette, 2003; Erdley et al., 2001; Kingery, Erdley, & Marshall, 2011). Correspondingly, chronic friendlessness predicts internalizing problems such as depression and social withdrawal, which often cause or accom- pany loneliness (Engle, McElwain, & Lasky, 2011; Ladd & Troop-Gordon, 2003; Palmen et al., 2011; S. Pedersen et al., 2007). The support of friends can be particularly important during difficult periods of transition that involve peers. For example, young children have more positive ini- tial attitudes toward school if they begin school with a large number of established friends as classmates (Ladd & Coleman, 1997; Ladd & Kochenderfer, 1996). In part, this may be because the presence of established friends in the early weeks of school reduces the strangeness of the new environment. Similarly, as 6th-graders move into junior high, they are more likely to increase their levels of sociability and leadership if they have stable, high-quality, intimate friendships during this period (Berndt, Hawkins, & Jiao, 1999). Friendships may also serve as a buffer against unpleasant experiences, such as being yelled at by the teacher, being excluded or victimized by peers (Bukowski, Laursen, & Hoza, 2010; Ladd, Kochenderfer, & Coleman, 1996; Waldrip, Malcolm, & Jensen-Campbell, 2008), or being socially isolated (i.e., having low levels of involvement with peers more generally; Laursen et al., 2007). In one study that demonstrated this effect, 5th- and 6th-graders reported on their nega- tive experiences over a 4-day period, indicating shortly after each such experience how they felt about themselves and whether or not a best friend had been present during each experience. The researchers also recorded the children’s cortisol levels multiple times each day, as a measure of the children’s stress reactions. The study showed that when a best friend was not present, the more negative children’s ev- eryday experiences were, the greater the increase in their cortisol levels and the greater the decline in their sense of self-worth following each experience (R. E. Adams, Santo, & Bukowski, 2011). In contrast, when a best friend was present, there was less change in cortisol responding and in the child’s self-worth due to negative experiences. This buffering effect of friends is especially clear for victimized children. Victim- ized children fare better if they have a number of reciprocated friendships (Hodges et al., 1999; D. Schwartz et al., 1999), if their friends are capable of defending them and are liked by peers (Hodges et al., 1997), and if their friendships are of high quality—that is, are perceived as providing intimacy, security, and help when needed (Kawabata, Crick, & Hamaguchi, 2010; M. E. Schmidt & Bagwell, 2007). As noted previously, the degree to which friends provide caring and support generally increases from childhood into adolescence (De Goede, Branje, & Meeus, 2009). Indeed, around age 16, adolescents, especially girls, report that friends are more impor- tant confidantes and providers of support than their parents are (Bokhorst, Sumter, & Westenberg, 2010; Furman & Buhrmester, 1992; Helsen, Vollebergh, & Meeus, 2000; Hunter & Youniss, 1982) (Figure 13.1). 2nd 5th 7th 10th College Single Married w/o kids Married w/kids 5 4 3 2 1 R at ed i n ti m at e d is cl os u re Friend Romantic Partner Parents FIGURE 13.1 Age trends in reports of self-disclosure to parents and peers By early adolescence, children disclose more to friends than to their parents. Young adults continue to disclose much more to friends than to their parents, but by college age they disclose most to romantic partners. (Adapted from Burmeister, 1996) F R I E N D S H I P S n 519 The Development of Social and Cognitive Skills Friendships provide a context for the development of social skills and knowledge that children need to form positive relationships with other people. As discussed earlier, young children seem to first develop more complex play in interactions with friends; and throughout childhood, cooperation, negotiation, and the like are all more common among friends than among nonfriends. In addition, young chil- dren who discuss emotions with their friends and interact with them in positive ways develop a better understanding of others’ mental and emotional states than do children whose peer relationships are less close (C. Hughes & Dunn, 1998; Maguire & Dunn, 1997). These skills can be brought to bear when helping their friends. In a study of 3rd- to 9th-graders over the course of the school year, those with high-quality friendships improved in the quality of their reported strategies for helping friends deal with social stressors. For example, they reported becoming more likely to be emotionally engaged in talking with their friend about a problem and less likely to act as though the problem did not exist (Glick & Rose, 2011). Friendship provides other avenues to social and cogni- tive development as well. Through gossip with friends about other children, for example, children learn about peer norms, including how, why, and when to display or control the ex- pression of emotions and other behaviors (Gottman, 1986; McDonald et al., 2007). As Piaget pointed out, friends are more likely than nonfriends to criticize and elaborate on one another’s ideas and to elaborate and clarify their own ideas (Azmitia & Montgomery, 1993; J. Nelson & Aboud, 1985). This kind of openness promotes cognitive skills and en- hances performance on creative tasks (Miell, 2000; Rubin et al., 2006). One demonstration of this was provided by a study in which teams of 10-year-olds, half of them made up of friends and the other half made up of nonfriends, were assigned to write a story about rain forests. The teams con- sisting of friends engaged in more constructive conversa- tions (e.g., they posed alternative approaches and provided elaborations more frequently) and were more focused on the task than were teams of nonfriends. In addition, the stories written by friends were of higher quality than those written by nonfriends (Hartup, 1996). Gender Differences in the Functions of Friendships As children grow older, gender differences emerge in what girls and boys feel they want and get from their friendships. Girls are more likely than boys to desire close- ness and dependency in friendships and also to worry about abandonment, loneli- ness, hurting others, peers’ evaluations, and loss of relationships if they express anger (A. J. Rose & Rudolph, 2006). By late elementary school, girls, compared with boys, feel that their friendships are more intimate and provide more validation, caring, help, and guidance (Bauminger et al., 2008; A. J. Rose & Rudolph, 2006; Zarbatany, McDougall, & Hymel, 2000). For instance, girls are more likely than boys to report that they rely on their friends for advice or help with homework, that they and their friends share confidences and stick up for one another, and that their friends tell them that they are good at things and make them feel special. Probably as a consequence of this intimacy, girls also report getting more upset than do boys when friends betray them, are unreliable, or do not provide support Interactions with friends provide children with opportunities to get constructive feed- back regarding their behavior and ideas. T O N Y F R E E M A N / P H O T O E D IT 520 n chApter 13 PEER RELATIONSHIPS and help (MacEvoy & Asher, 2012). Girls also report more friendship-related stress, such as when a friend breaks off a friendship or reveals their secrets or prob- lems to other friends, and greater stress from dealing emotionally with stressors that their friends experience (A. J. Rose & Rudolph, 2006). Ironically, the very intimacy of girls’ close friendships may make them more fragile, and therefore of shorter duration, than those of boys (Benenson & Christakos, 2003; A. Chan & Poulin, 2007; C. L. Hardy, Bukowski, & Sippola 2002). As discussed in Chapter 10 (page 396), girls are also more likely than boys to co-ruminate with their close friends, that is, to extensively discuss problems and nega- tive thoughts and feelings (R. L. Smith & Rose, 2011). And compared with their male counterparts, girls who are socially anxious or depressed seem more susceptible to the anxiety or depression of their friends (Giletta et al., 2011; M. H. van Zalk et al., 2010; N. van Zalk et al., 2011). Unfortunately, while providing support, a co-ru- minating anxious or depressed friend may also reinforce the other friend’s anxiety or depression, especially in young adolescent girls (A. J. Rose, Carlson, & Waller, 2007; Schwartz-Mette & Rose, 2012). Girls and boys are less likely to differ in the amount of conflict they experience in their best friendships (A. J. Rose & Rudolph, 2006). Boys’ and girls’ friend- ships also do not differ much in terms of the recreational opportunities they pro- vide (e.g., doing things together, going to one another’s house) (Parker & Asher, 1993), although they often differ in the time spent together in various activities (e.g., sports versus shopping; A. J. Rose & Rudolph, 2006). Effects of Friendships on Psychological Functioning and Behavior over Time Because friendships fill important needs for children, it might be expected that hav- ing friends enhances children’s social and emotional health. In fact, having close, reciprocated friendships in elementary school has been linked to a variety of posi- tive psychological and behavioral outcomes for children, not only during the school years but also years later in early adulthood. However, there also may be costs to having friends, if the friends engage in or encourage negative behaviors rather than positive ones (Simpkins, Eccles, & Becnel, 2008). The Possible Long-Term Benefits of Having Friends Longitudinal research provides the best data concerning the possible long-term benefits of having friends in elementary school. Because this research is generally correlational, however, it is difficult to determine if having friends influences long- term outcomes such as psychological adjustment, or if characteristics of the child (such as psychological adjustment) affect whether the child has friends (Klima & Repetti, 2008). Typical of this research is a study that examined the relation between the quality of friendship and the development of aggression. In this study, researchers followed children from kindergarten to 2nd grade and found that children with high-quality friendships became less physically aggressive over time (Salvas et al., 2011). In an- other, broader, longitudinal study, researchers looked at children when they were 5th-graders and when they were young adults. They found that, compared with their peers who did not have reciprocated best friendships, 5th-graders who did have them were viewed by classmates as more mature and competent, less aggres- sive, and more socially prominent (e.g., they were liked by everyone or were picked for such positions as class president or team captain). At approximately age 23, those reciprocated best friendship n a friendship in which two children view each other as best or close friends F R I E N D S H I P S n 521 individuals who had reciprocated best friendships in 5th grade reported higher levels of doing well in college and in their family and social life than did individuals who did not have a reciprocated best friendship. They also reported higher levels of self- esteem, fewer problems with the law, and less psychopathology (e.g., depression) (Bagwell, Newcomb, & Bukowski, 1998). Thus, having a reciprocated best friend- ship in preadolescence relates not only to positive social outcomes in middle child- hood but also to self-perceived competence and adjustment in adulthood. The Possible Costs of Friendships Although friendships are usually associated with positive outcomes, sometimes they are not. Friends who have behavioral problems may exert a detrimental influ- ence, contributing to the likelihood of a child’s or adolescent’s engaging in violence, drug use, or other negative behaviors. And as previously noted, friends who are depressed may foster depression in their close friends, in part through a contagion effect (Dishion & Tipsord, 2011). Aggression and disruptiveness In the elementary school years and early adoles- cence, children who have antisocial and aggressive friends tend to exhibit antiso- cial, delinquent, and aggressive tendencies themselves, even across time (Brendgen, Vitaro, & Bukowski, 2000; J. Snyder et al., 2008). However, the research in this area is correlational, so it is difficult to know to what degree this pattern reflects socialization or individual selection. With regard to individual selection, aggressive and disruptive children may gravitate toward peers who are similar to themselves in temperament, preferred activities, or attitudes, thereby taking an active role in creating their own peer group (Knecht et al., 2010; Mrug, Hoza, & Bukowski, 2004). At the same time, friends appear to affect one another’s behavior (Vitaro, Pedersen, & Brendgen, 2007). Through their talk and behavior, youths who are antisocial may socialize and reinforce aggression and deviance in one another by making these behaviors seem acceptable (Dishion & Tipsord, 2011; Piehler & Dishion, 2007). This pattern is more likely to occur with those adolescents who are easily influenced by peers hold- ing high status in the peer group (Prinstein, Brechwald, & Cohen, 2011) or by friends whose peer-group status is higher than their own (Laursen et al., 2012). The factors accounting for the association between friends’ antisocial behav- ior may change with age. One longitudinal study found that both selection and socialization processes were in play in mid-adolescence, but that from ages 16 to 20, antisocial behavior was reinforced only through social- ization by friends. After age 20, an age past which youths become more resistant to peer influence, there was little evidence of either process occurring (Monahan, Stein- berg, & Cauffman, 2009). Alcohol and substance abuse As in the case of ag- gression, adolescents who abuse alcohol or drugs tend to have friends who do so also ( Jaccard, Blanton, & Dodge, 2005; Scholte et al., 2008; Urberg, Değirmencioğlu, & Pilgrim 1997). And again, as in the case of aggression, it is not clear if friends’ substance abuse is a cause or merely a correlate of adolescents’ substance abuse, or if the rela- tion between the two is bidirectional. On the one hand, there is some evidence that adoles- cents tend to select friends who are similar to themselves in terms of drinking and the use of drugs (Knecht et al., peers can encourage youths to use alcohol, but it is also the case that youths who are prone to drinking may seek out peers who are similarly inclined. O C E A N / C O R B IS 522 n chApter 13 PEER RELATIONSHIPS 2011), and this may be especially true for those youths who are highly susceptible to peer pressure (Schulenberg et al., 1999). However, there is also evidence that peer socialization influences drug and alcohol use (Branstetter, Low, & Furman, 2011). For example, adolescents who start drinking or smoking tend to have a close friend who has been using alcohol or tobacco (Selfhout, Branje, & Meeus, 2008; Urberg et al., 1997). Youths who are highly susceptible to the influence of their close friends seem particularly vulnerable to any pressure from them to use drugs and alcohol (Allen, Porter, & McFarland, 2006), and, as in the case of aggression, this is especially the case if those friends have high status in the peer group (Allen et al., 2012). There is also evidence that adolescents’ use of alcohol and drugs and their friend’s alcohol and substance use mutually reinforce each other, often result- ing in an escalation of use (Bray et al., 2003; Popp et al., 2008; Poulin et al., 2011). Yet another factor in the association between adolescents’ abuse of drugs and alcohol and that of their friends is their genetic makeup. Youths with similar genetically based temperamental characteristics such as risk-taking may be drawn both to one another and to alcohol or drugs (Dick et al., 2007; J. Hill et al., 2008). Thus, friends’ alcohol and drug abuse may be correlated because of their similarity Young children’s contact with unrelated peers varies considerably around the world. In some communities, such as one in Oki- nawa, Japan, Beatrice Whiting and Caro- lyn Edwards (1988) found that children were free to wander in the streets and pub- lic areas of town and had extensive contact with peers. In contrast, in some sub- Saharan African societies, children were confined primarily to the family yard and therefore had relatively little contact with peers other than their siblings. As might be expected, Whiting and Edwards found that children’s access to the wider community, including peers, increased with age. However, even when children were aged 6 to 10, there were marked differences in the extent to which their social interac- tions extended beyond the family. In large measure, these differences were based on parents’ attitudes toward childhood peer relationships. For example, in kin-based societies such as Kenya, peer interactions were discouraged: Parents feared the inherent potential for competition and conflict; they did not want their children to fight with outsiders and engender spiteful rela- tions or become vulnerable to aggres- sion and sorcery. Moreover, as their children did not attend school, they had no need for them to easily acquire skills of affiliating, negotiating, and competing with nonfamily agemates. (C. P. Edwards, 1992, p. 305) However, Edwards noted that the situ- ation in Kenya is changing as the econ- omy modernizes and literacy becomes an increasingly valued skill. Parents usually want their children to be educated, and ed- ucation involves contact with peers. Indeed, in numerous kin-based societies, levels of interaction with peers who are not from the child’s family or clan increased dramatically when Westernized schooling was established (Rogoff, 2003; Tietjen, 2006), although in some cases, this contact has been restricted primarily to the school setting. Cultures differ in terms of the total num- ber of hours that children typically spend with peers. In many cultures, especially in unschooled, nonindustrial populations, boys tend to spend more time with peers than girls do, likely because they are less closely moni- tored and are allowed greater freedom to be away from home (Larson & Verma, 1999). For example, 6- to 12-year-old Indian boys were found to spend three times as much time with their peers outside their families than girls did (Saraswati & Dutta, 1988). Among postindustrial schooled pop- ulations, European American, African American, and European adolescents have been found to spend much more time with peers, especially other-gender peers, than Asian adolescents do (Larson & Verma, 1999). In one study, for example, U.S. ad- olescents spent 18.4 hours per week with friends outside the classroom, whereas the time their Japanese and Taiwanese counter- parts spent in out-of-school peer contact was, respectively, 12.4 and 8.8 hours per week (Fuligni & Stevenson, 1995). Moreover, East Asians tended to spend more of their time with peers studying than did U.S. youths, who were more inclined to engage in leisure activities with peers. Similar differences were evident in time spent dating, with Japanese and Taiwanese 11th-graders devoting roughly an hour a week to dating, compared with 4.7 hours per week for U.S. youths. The cross-cultural differences in the amount of peer interaction adolescents en- gage in is likely due, at least in part, to cul- tural differences in values about what is important. A recent study of adolescents in 11 countries found that the greater the importance of traditional family values— defined as high feelings of family obliga- tions, acceptance of children’s duty to be obedient, and an orientation toward the BOX 13.1: individual differences CULTURE AND CHILDREN’S PEER EXPERIENCE F R I E N D S H I P S n 523 in genetically based characteristics as well as in their socialization experiences, although the effect of a group of friends on youths’ drinking is not due solely to genetics (Cruz, Emery, & Turkheimer, 2012). The extent to which friends’ use of drugs and alcohol may put adolescents at risk for use themselves seems to depend, in part, on the nature of the child–parent rela- tionship. An adolescent with a substance-using close friend is at risk primarily if the adolescent’s parents are cold, detached, and uninclined to monitor and supervise the adolescent’s activities (Kiesner, Poulin, & Dishion, 2010; Mounts & Steinberg, 1995; Pilgrim et al., 1999). If the adolescent’s parents are authoritative in their parenting— monitoring their child’s behavior and setting firm limits, but also being warm and receptive to the adolescent’s viewpoint (see Chapter 12, pages 473–474)—the adoles- cent is more likely to be protected against peer pressure to use drugs (Mounts, 2002). Children’s Choice of Friends What factors influence children’s choices of friends? As noted earlier, for young children, proximity is an obvious key factor. Preschoolers tend to become friends with peers who are nearby physically, as neighbors or playgroup members. (As family instead of a focus on autonomy and individualism—the less peer acceptance was related to adolescents’ life satisfac- tion (Schwarz et al., 2012). Thus, in cul- tures with traditional family values, the peer group appears less important, and adoles- cents’ well-being is less related to how well liked they are by peers. Adults’ expectations in regard to the nature of children’s interactions with peers also tend to differ across cultures. For example, there are cultural differences in the degree to which parents expect their children to develop such social skills as ne- gotiating, taking the initiative, and stand- ing up for their rights with peers. European American and European Australian mothers expect their children to develop such skills earlier than do Japanese mothers (Hess et al., 1980) and Lebanese Australian moth- ers (Goodnow et al., 1984). This is probably because the European American and Eu- ropean Australian mothers are influenced by their respective culture’s emphasis on personal autonomy and independence and believe that the aforementioned skills are important for success. Correspondingly, Japanese mothers and Australian mothers of Lebanese heritage are likely to be similarly influenced by their respective cultures’ emphasis on the inter- dependence of family members; therefore, they may be more likely to accept or even encourage dependency in young children (F. A. Johnson, 1993; M. I. White & LeVine, 1986). Thus, differences in parents’ ex- pectations regarding what social skills their children will develop and by what age likely influence what parents teach their children about social interactions with peers. In some groups in Kenya, children are discouraged from forming relationships with peers who are not related. thus, children interact primarily with siblings and adult relatives. M O R T O N B E E B E / C O R B IS 524 n chApter 13 PEER RELATIONSHIPS Box 13.1 points out, young children’s access to peers can vary widely by cul- ture.) Although proximity becomes less important with age, it continues to play a role in individuals’ choices of friends in adolescence (Clarke-McLean, 1996; Dishion, Andrews, & Crosby, 1995). This is partly because one form of prox- imity is involvement in similar activities at school (e.g., sports, academic activi- ties, arts), which appears to promote the development of new friendships. In one study, when two adolescents participated in the same activity, they were on aver- age 2.3 times more likely to be friends than were adolescents who did not par- ticipate in the same activity (Schaefer et al., 2011). In most industrialized countries, similarity in age is also a major factor in friendship, with most children tending to make friends with age-mates (Aboud & Mendelson, 1996; Dishion et al., 1995). In part, this may be due to the fact that in most industrialized societies, children are segregated by age in school: in societies where children do not attend school or otherwise are not segregated by age, they are more likely to develop friendships with children of different ages. Another powerful factor in friend selection is a child’s gender: girls tend to be friends with girls, and boys, with boys (Knecht et al., 2011; C. L. Martin et al., 2013; A. J. Rose & Rudolph, 2006). Cross-gender friendships, though not uncommon, tend to be more fragile (L. Lee, Howes, & Chamberlain, 2007; Maccoby, 2000; see Chapter 15). The preference for same-gender friends emerges in preschool and continues through childhood (Hartup, 1983). The liking of other-gender peers also increases over the course of childhood and into early adolescence (Poulin & Pedersen, 2007), with other-gender close friendships increasing in frequency from 8th grade to 11th grade (Arndorfer & Stormshak, 2008). To a lesser degree, children tend to be friends with peers of their own racial/ ethnic group, although this tendency varies across groups and contexts (Knecht et al., 2011). In general, efforts to establish friendships outside one’s own racial/ ethnic group are less likely to be reciprocated than are efforts within the group (Vaquera & Kao, 2008); and when they are reciprocated, they often are not as long-lasting (L. Lee et al., 2007). In general, those youths with cross-racial/eth- nic friendships tend to be leaders and relatively inclusive in their social rela- tionships (Kawabata & Crick, 2008), as well as socially competent and high in self-esteem (N. Eisenberg, Valiente et al., 2009; Fletcher, Rollins, & Nickerson, 2004; Kawabata & Crick, 2011). For majority-group children, having cross-eth- nic friendships has been associated with positive attitudes toward people in other groups in the future (Feddes, Noack, & Rutland, 2009). However, cross-race friendships can have costs: for example, middle-school African American and Asian American youths whose best friends are only of a different race from their own tend to be lower in emotional well-being than those with best friends only from the same racial group (McGill, Way, & Hughes, 2012). Beyond these basic factors, a key determinant of liking and friendship is simi- larity of interests and behavior. By age 7, children tend to like peers who are similar to themselves in the cognitive maturity of their play (Rubin et al., 1994) and in the level of their aggressive behavior (Poulin et al., 1997). Between 4th grade and 8th grade, friends are more similar than nonfriends in their cooperative- ness, antisocial behavior, acceptance by peers, and shyness (X. Chen, Cen et al., 2005; Haselager et al., 1998; A. J. Rose, Swenson, & Carlson, 2004). They are also more similar in their level of academic motivation and self-perceptions of compe- tence (Altermatt & Pomerantz, 2003). Much the same pattern holds for adoles- cents (Dijkstra, Cillessen, & Borch, 2012; Gavin & Furman, 1996; Rubin et al., P E E R S I N G R O U P S n 525 2006), with the added dimensions that friends also tend to share similar levels of negative emotions such as distress and depression (Haselager et al., 1998; Hogue & Steinberg, 1995) and are similar in their tendency to attribute hostile intentions to others (Halligan & Philips, 2010). Thus, birds of a feather do tend to flock together. The fact that friends tend to be similar on a number of dimensions underscores the difficulty of knowing whether friends actually affect one another’s behavior or whether children simply seek out peers who think, act, and feel as they do. review: Peers, especially friends, provide intimacy, support, and rich opportunities for the development of play and for the exchange of ideas. Children engage in more complex and cooperative play, and in more conflict, with friends than with nonfriends, and they tend to resolve conflicts with friends in more appropriate ways. With age, the dimensions of chil- dren’s friendships change somewhat. Whereas young children define friendship primarily on the basis of actual activities with their peers and on the rewards and costs involved, older children increasingly rely on their friends to provide a context for self-disclosure, intimacy, self- exploration, and problem solving. As was suggested by Piaget and Vygotsky, friends also provide opportunities for the development of important social and cognitive skills. However, friends can have negative effects on children if they engage in problematic behaviors such as aggression or substance abuse. Children tend to become friends with peers who are similar in age, sex, race, and social behavior. This makes it especially difficult to distinguish between characteristics that chil- dren bring to friendships and the effects of friends on one another. Peers in Groups Most children usually have one or a few very close friends and some less close additional friends with whom they spend time and share activities. These groups tend to exist within a larger social network of peers that hangs together loosely. Developmentalists have been especially interested in how these peer groups emerge and change with age and how they affect the development of their members. The Nature of Young Children’s Groups When in a setting with a number of their peers, very young children, including tod- dlers, sometimes interact in small groups. One striking feature of these first peer groups is the early emergence of status patterns within them, with some children being more dominant and central to group activities than are others (Rubin et al., 2006). By the time children are preschool age, there is a clear dominance hierar- chy among the members of a peer group. Certain children are likely to prevail over other group members when there is conflict, and there is a consistent pattern of winners and losers in physical confrontations. As we will discuss shortly, by middle childhood, status in the peer groups involves much more than dominance, and children become very concerned about their peer-group standing. Before examining peer status, however, we need to con- sider the nature of social groups in middle childhood and early adolescence. 526 n chApter 13 PEER RELATIONSHIPS Cliques and Social Networks in Middle Childhood and Early Adolescence Starting in middle childhood, most children are part of a clique. Cliques are friend- ship groups that children voluntarily form or join themselves. In middle childhood, clique members are usually of the same sex and race and typically number be- tween 3 and 10 (X. Chen, Chang, & He, 2003; Kwon, Lease, & Hoffman, 2012; Neal, 2010; Rubin et al., 2006). Boys’ groups tend to be larger than those of girls (Benenson, Morganstein, & Roy, 1998), although this difference decreases with age (Neal, 2010). By age 11, many of children’s social interactions—from gatherings in the school lunchroom to outings at the mall—occur within the clique (Crockett, Losoff, & Peterson, 1984). Although friends tend to be members of the same clique, many members of a clique do not view each other as close friends (Cairns et al., 1995). A key feature that underlies cliques and binds their members together is the similarities the members share. Like friends, members of cliques tend to be simi- lar in their degree of academic motivation (Kindermann, 2007; Kiuru et al., 2009); in their aggressiveness and bullying; and in their shyness, attractiveness, popular- ity, and adherence to conventional values such as politeness and cooperativeness (Espelage, Holt, & Henkel, 2003; Kiesner, Poulin, & Nicotra, 2003; Leung, 1996; Salmivalli & Voeten, 2004; Witvliet et al., 2010). Not only do like individuals tend to group together in cliques, but membership in a clique also seems to increase the likelihood that children will exhibit behaviors similar to those of other group mem- bers (Espelage et al., 2003). Despite the social glue of similarity, the membership of cliques tends to be rela- tively unstable (Cairns et al., 1995). A study of 4th- and 5th-graders, for example, found the turnover rate of cliques to be about 50% over 8 months (Kindermann, 1993); and in a study of 6th-graders, only about 60% of the members of cliques maintained their group ties over the school year (Kindermann, 2007). The degree to which cliques remain stable appears to depend in large part on whether children are assigned to the same classroom from one year to the next (Neckerman, 1996). In contrast to the tendency of dominant children to be the central figures in young children’s groups, during the school years, girls and boys who are central to the peer group are likely to be popular, athletic, cooperative, seen as leaders, and studious relative to other peers (Farmer & Rodkin, 1996). However, especially in the case of boys, and more especially in the case of aggressive groups of youths, the central figures are sometimes domineering, aggressive, and viewed by peers as “tough” or “cool” (Estell et al., 2002; Rodkin et al., 2006). Cliques in middle childhood serve a variety of functions: they provide a ready- made pool of peers for socializing; they offer validation of the characteristics that the group members have in common; and, perhaps most important, they provide a sense of belonging. By middle childhood, children are quite concerned about being accepted by peers, and issues of peer status become a common topic of children’s con- versation and gossip (Gottman, 1986; Kanner et al., 1987; Rubin et al., 1998). Being accepted by others who are similar to oneself in various ways may provide a sense of personal affirmation, as well as of being a welcomed member of the larger peer group. Cliques and Social Networks in Adolescence From ages 11 to 18, there is a marked drop in the number of students who belong to a single clique and an increase in the number of adolescents who have ties to many cliques or to students at the margins of cliques (Shrum & Cheek, 1987). In cliques n friendship groups that children voluntarily form or join themselves P E E R S I N G R O U P S n 527 addition, membership in a clique is fairly stable across the school year by 10th grade (Degirmencioglu et al., 1998). Although cliques at younger ages contain mostly same-sex members, by 7th grade, about 10% of cliques contain both boys and girls (Cairns et al., 1995). Thereafter, dyadic dating relationships become increasingly common (Dunphy, 1963; Richards et al., 1998); thus, by high school, cliques of friends often include adolescents of both genders ( J. L. Fischer, Sollie, & Morrow, 1986; La Greca, Prinstein, & Fetter, 2001). The dynamics of cliques also vary at different ages in adolescence. During early and middle adolescence, children report placing a high value on being in a popular group and in conforming to the group’s norms regarding dress and behavior. Fail- ure to conform—even something as trivial-seeming as wearing the wrong brand or style of jeans or belonging to an afterschool club that is viewed as uncool—can result in being ridiculed or shunned by the group. In comparison with older adolescents, younger adolescents also report more interpersonal conflict with members of their group as well as with members of other groups. In later ado- lescence, the importance of belonging to a clique and of conforming to its norms appears to decline, which may account for the decline in friction and antagonism within and between groups. With increasing age, ado- lescents not only are more autonomous but they also tend to look more to individual relationships than to group relationships to fulfill their social needs (Gavin & Furman, 1989; Rubin et al., 1998). Although older adolescents seem less tied to cliques, they still often belong to crowds. Crowds are groups of people who have similar stereotyped reputations. Among high school students, typical crowds may in- clude the “brains,” “jocks,” “loners,” “burnouts,” “punks,” “populars,” “elites,” “freaks,” “hip-hoppers,” “geeks,” “normals,” and “metalheads” (B. B. Brown & Klute, 2003; Delsing et al., 2007; Doornwaard et al., 2012; La Greca et al., 2001). Which crowd adolescents belong to is often not their choice; crowd “membership” is frequently assigned to the individual by the consensus of the peer group, even though the indi- vidual may actually spend little time with other members of that designated crowd (B. B. Brown, 1990). Being associated with a crowd may enhance or hurt adolescents’ reputations and influence how they are treated by peers. Someone labeled a freak, for example, may be ignored or ridiculed by people in groups such as the jocks or the populars (S. S. Horn, 2003). Thus, it is not surprising that youths in high- status groups tend to have higher self-esteem than do youths in less desirable crowds (B. B. Brown, Bank, & Steinberg, 2008). Being labeled as part of a particular crowd also may limit ado- lescents’ options with regard to exploring their identities (see Chapter 11). This is because crowd membership may “channel” adolescents into relationships with other members of the same crowd rather than with a diverse group of peers (B. B. Brown, 2004; Eckert, 1989). Adolescents in one crowd, for instance, might be exposed to their peers’ acceptance of violence or drug use, whereas members of another crowd may find that their peers value success in academics or sports (La Greca et al., 2001). An example of the potential consequences of such channeling comes from a large study in Holland that found that adolescents’ persistent identification with nonconventional crowds (e.g., hip-hoppers, nonconformists, and metalheads) crowds n groups of adolescents who have similar stereotyped reputations; among American high school students, typical crowds may include the “brains,” “jocks,” “loners,” “burnouts,” “punks,” “populars,” “elites,” “freaks,” or “nonconformists” children and adolescents in cliques tend to spend a lot of time together and often dress similarly. M A R T IN T H O M A S P H O T O G R A P H Y / A LA M Y 528 n chApter 13 PEER RELATIONSHIPS was associated with more consistent problem behaviors throughout adolescence, whereas adolescents’ consistent identification with conventional groups was gen- erally associated with less problematic behavior (Doornwaard et al., 2012). Thus, experiences in a crowd, like interactions with friends, may help shape youths’ behavior. A relatively new dimension in which peers interact, one that they have used with increasing frequency in recent years, is cyberspace. As Box 13.2 explains, youths’ most frequent form of contact with friends and peers is now digital communica- tion, and the role and effects, both positive and negative, of this venue have become subjects of considerable debate. Negative Influences of Cliques and Social Networks Like close friends, members of the clique or the larger peer network can sometimes lead the child or adolescent astray. Preadolescents and adolescents are more likely to goof off in school, smoke, drink, use drugs, or engage in violence, for example, if members of their peer group do so and if they hang out with peers who have been in trouble (Lacourse et al., 2003; Loukas et al., 2008). Adolescents who have an extreme orientation to peers—that is, who are willing to do anything to be liked by peers— are particularly at risk for such behaviors if engaging in them secures peer acceptance (Fuligni et al., 2001). Adolescents who are low in self-regulation are also at increased risk if their peers are antisocial (T. W. Gardner, Dishion, & Connell, 2008). Perhaps the greatest potential for negative peer-group influence comes with membership in a gang, which is a loosely organized group of adolescents or young adults who identify as a group and often engage in illegal activities. Gang members often say that they join or stay in a gang for protection from other gangs. One male gang member explained that “being cool with a gang” meant that “you don’t have to worry about nobody jumping you. You don’t got to worry about getting beat up” (quoted in Decker, 1996, p. 253). Gangs also provide members with a sense of belonging and a way to spend their time. Gang members frequently report that the most common gang activities are “hanging out” together and engaging in fairly innocuous behaviors (e.g., drinking beer, playing sports, cruising, looking for girls, and having parties) (Decker & van Winkle, 1996). Nonetheless, adolescents tend to engage in more illegal activities such as delinquency and drug abuse when they are in a gang than when they are not (Alleyne & Wood, 2010; Bjerregaard & Smith, 1993; Craig et al., 2002; Esbensen & Huizinga, 1993; see Chapter 14, page 587), and the heightened risk for such activities seems to be due to both pre-existing characteristics of the adolescents who join gangs and their experience of being in a gang (Barnes, Beaver, & Miller, 2010; Delisi et al., 2009). The potential for peer-group influence to promote problem behavior is affected by family and cultural influences. As noted in our discussion of friendship, having authoritative, involved parents helps protect adolescents from peer pressure to use drugs, whereas having authoritarian, detached parents increases adolescents’ sus- ceptibility to such pressure. Correspondingly, youths who have poor relationships with their mothers may be especially vulnerable to pressure from the peer group (Farrell & White, 1998). At the same time, the strength of peer influence on problem behavior can vary by culture and subculture. For example, compared with its strength among European American adolescents, peer influence on the use of drugs, drinking, aggression, or school misconduct appears to be weaker for Native American youths gang n a loosely organized group of ado- lescents or young adults who identify as a group and often engage in illegal activities P E E R S I N G R O U P S n 529 BOX 13.2: a closer look CYBERSPACE AND CHILDREN’S PEER EXPERIENCE Technology such as online social media, instant messaging, and phone texting are playing an increasing role in peer inter- actions of children and especially of ado- lescents. According to a report on the 2009 online activities of U.S. adolescents aged 12 to 17, 73% used social network sites, 67% used instant messaging, 78% played online games, and 49% read blogs (Zickuhr, 2010). Almost three-fourths of online adolescents and adults in their mid- 20s or younger had joined a social network- ing site such as MySpace or Facebook, where they created a descriptive personal profile and built a network with other users (Lenhart et al., 2010). In addition, a report on U.S. adolescents’ cell phone use in 2009 indicated that approximately 75% of 12- to 17-year-olds owned their own cell phones and that 72% of all adolescents engaged in text messag- ing. The frequency of texting was high: a large survey in four cities showed that 54% of teens between the ages of 12 and 17 texted friends daily, with about half of these teens sending 50 or more text messages a day and one-third sending more than 100 texts a day (Lenhart et al., 2010). Given youths’ tremendous use of digital technologies for their social interactions, social and behavioral scientists, as well as parents, have expressed considerable con- cern about the effects that these modes of communication may have on children’s and adolescents’ social development—and es- pecially on their social relationships. Two major perspectives have guided research on this issue. One view is the rich-get-richer hy- pothesis, which proposes that those youths who already have good social skills bene- fit from the Internet and related forms of technology when it comes to developing friendships (Peter, Valkenburg, & Schouten, 2005). In contrast, according to the social- compensation hypothesis, social media may be especially beneficial for lonely, depressed, and socially anxious adoles- cents. Specifically, because they can take their time thinking about, and revising, what they say and reveal in their messages, these youths may be more likely to make per- sonal disclosures online than offline, which eventually fosters the formation of new friendships. In support of the rich-get-richer hypothesis, researchers have found that adolescents who are not socially anxious or lonely use the Internet for communica- tion more often than do adolescents who are (Valkenburg & Peter, 2007b; Van den Eijnden et al., 2008). Moreover, youths who were better adjusted at age 13 to 14 were found to use social networking more at ages 20 to 22 and to exhibit a similarity in their online and offline social competence (e.g., in peer relationships, friendship quality, adjustment) (Mikami et al., 2010). Thus, socially competent people may benefit most from the Internet because they are more likely to interact in appropriate and positive ways when engaged in social networking. However, consistent with the social- compensation hypothesis, lonely and socially anxious youths seem to prefer online communication over face-to-face communication (Peter et al., 2005; Pierce, 2009). There is also evidence that online communication is used by youths with high levels of depressive symptoms to make friends and express their feelings (J. M. Hwang, Cheong, & Feeley, 2009), and that such use is associated with less depres- sion for youths with low-quality best-friend relationships (Selfhout et al., 2009). Thus, the use of online technology often may pro- vide depressed youths or those with low- quality offline friendships a means of obtaining communication and emotional intimacy with peers. Another issue is how online com- munication may affect youths’ existing friendships. Some investigators have hy- pothesized that online communication impairs the quality of existing friendships because it displaces the time that could be spent strengthening the affection and commitment these friendships can pro- vide (Kraut et al., 1998; see Valkenburg & Peter, 2011). Alternatively, other investi- gators have hypothesized that recent Inter- net-based communication technologies are designed to facilitate communication among existing friends, allowing them to maintain and enhance the closeness of their rela- tionships (J. A. Bryant, Sanders-Jackson, & Smallwood, 2006; Peter et al., 2005; Valkenburg & Peter, 2011). Overall, the latter view has received more support (Valkenburg & Peter, 2007a, 2009a, b; Valkenburg & Peter, 2011). In existing friendships, online communica- tion seems to foster self- disclosure, which enhances friendship quality. In fact, many adolescents tend to use social-networking sites to connect with people they know off- line and to strengthen these preexisting relationships (Reich, Subrahmanyam, & Espinoza, 2012). Similarly, the use of in- stant messaging has been associated with an increase in the quality of adolescents’ existing friendships over time (Valken- burg & Peter, 2009b). In contrast, high levels of using the Internet primarily for entertainment (e.g., playing games, surf- ing) or for communication with strang- ers can harm the quality of friendships (Blais et al., 2008; Punamäki et al., 2009; Valkenburg & Peter, 2007b) and predicts increases in anxiety and depression (Selfhout et al., 2009). Another potential risk of online use— one that is quite serious—is cyberbullying among adolescents (Kiriakidis & Kavoura, 2010; Kowalski, Limber, & Agatston, 2008; Tokunaga, 2010). Internet applications can be used by youths to intimidate, insult, and humiliate peers and ensure a much larger group of peer witnesses than is possible in everyday face-to-face in teractions. Cyber- bullies and cybervictims tend to be the same youths who are bullies or victims off- line (Twyman et al., 2010). Cyber victims, like victims offline, tend to be high in so- cial anxiety, psychological distress, and (continued) 530 n chApter 13 PEER RELATIONSHIPS symptoms of depression, as well as to have aggressive tendencies, poor anger manage- ment, and problems at school (Valkenburg & Peter, 2011). However, nearly all the rel- evant research is correlational, so it is not clear if youths with these characteristics elicit cyberbullying, if cyberbullying causes emotional and behavioral problems, or if both factors come into play. Although social media are often used to bully peers, they also may be helpful in countering the effects of peer rejection. In an experimental study, adolescents and young adults played what they were led to believe was an online interactive game with unfamiliar peers (Reijntjes, Thomaes et al., 2011). Actually, the game is a standardized laboratory computer program designed to elicit feelings of social inclusion or exclu- sion in the only real player—the research participant. In the exclusion version, the program’s “other players” eventually begin to play among themselves, completely ignoring the participant. In this study, after the game ended, the excluded partici- pants showed lower levels of self-esteem and higher levels of anger and shame than did the included participants. Next, the excluded participants spent 12 minutes either playing a computer puzzle game by themselves or engaging in instant messag- ing with an unfamiliar other-sex person, with whom they were free to discuss any- thing except the just-completed game. The researchers found that excluded participants who engaged in the text mes- saging showed greater recovery from exclu- sion in terms of self- esteem and negative affect than did the excluded participants who played the puzzle game. These find- ings are consistent with the previously men- tioned benefits of cybercommunication for shy, anxious, or depressed individuals and suggest that Internet relationships can have benefits for children and youths who have difficulties with peer relationships. BOX 13.2: a closer look CYBERSPACE AND CHILDREN’S PEER EXPERIENCE (continued) Age P er ce n t Talk Face-to-Face 0 20 40 60 80 12 1716151413 Average 33% Age P er ce n t Call on Cell Phone 0 20 40 60 80 12 1716151413 Average 38% Age P er ce n t Text Messaging 0 20 40 60 80 12 1716151413 Average 54% the most common ways U.S. adolescents contact their friends. (Adapted from Lenhart et al., 2010) P E E R S I N G R O U P S n 531 who live on a reservation and for adolescents in mainland China or Taiwan (C. Chen et al., 1998; Swaim et al., 1993), perhaps because family sanctions against such behaviors play a more important role in these groups. Although the precise reasons for all these differences in peer-group influence are not yet known, it is clear from findings such as these that family and cultural factors can affect the degree to which peers’ behaviors are associated with adolescents’ problem behavior. Romantic Relationships with Peers In the United States, 25% of 12-year-olds and 70% of 18-year-olds report hav- ing had a recent romantic relationship (K. Carver, Joyner, & Udry, 2003). Similar rates have been reported for youth in Europe (Zani, 1991). For adolescents 15 years or younger, two-thirds of these romantic relationships, on average, do not last more than 11 months. For more than half of the older adolescents, they do (Collins, 2003). The path to heterosexual romantic relationships in adolescence typically begins in mixed-gender peer groups, with dating emerging out of mixed-gender affili- ations in these groups (Collins & Steinberg, 2006; Connolly et al., 2004). From ages 14 to 18, youth tend to balance the time they spend with romantic partners and with same-gender cliques, gradually decreasing the percent of time they spend in mixed-gender groups (Richards et al., 1998). However, by early adulthood, the time spent with romantic partners increases to the level that it is at the expense of involvement with friends and crowds (Reis et al., 1993). Less is known about the emergence of romantic relationships among sexual-minority youths: although most report some sexual activity in adolescence (Savin-Williams & Diamond, 2000), whether they date depends on the level of acceptance in their social environment (L. M. Diamond, Savin-Williams, & Dube, 1999). Young adolescents tend to be drawn to, and choose, partners on the basis of characteristics that bring status—such as being stylish and having the approval of peers (Pellegrini & Long, 2007). By middle to late adolescence, traits such as kindness, honesty, intelligence, and interpersonal skills are also important fac- tors in selecting a romantic partner (Ha et al., 2010; Regan & Joshi, 2003). Older adolescents are more likely than younger ones to select partners based on compat- ibility and characteristics that enhance intimacy, such as caring and compromise (Collins, 2003). For many adolescents, being in a romantic relationship is important for a sense of belonging and status in the peer group (W. Carlson & Rose, 2007; Connolly et al., 1999). By late adolescence, having a high-quality romantic relationship is also associated with feelings of self-worth and a general sense of competence (Collins, Welsh, & Furman, 2009; Connolly & Konarski, 1994), and it can improve func- tioning in adolescents who are prone to depression, sadness, or aggression (V. A. Simon, Aikins, & Prinstein, 2008). However, romantic relationships can also have negative effects on development. Early dating and sexual activity, for example, are associated with increased rates of current and later problem behaviors, such as drinking and using drugs, as well as with social and emotional difficulties (e.g., Davies & Windle, 2000; Zimmer- Gembeck, Siebenbruner, & Collins, 2001). This is especially true if the romantic partner is prone to delinquent behavior (Lonardo et al., 2009; S. Miller et al., 2009). When a romantic relationship doesn’t work out, hurt feelings for one or both partners are par for the course, but girls who are treated badly or are rejected in a relationship seem particularly prone to depression and anxiety (W. E. Ellis, Crooks, & Wolfe, 2009). B U B B LE S P H O T O LI B R A R Y / A LA M Y the importance of compatibility and caring in romantic relationships increases with age in adolescence. 532 n chApter 13 PEER RELATIONSHIPS The quality of adolescents’ romantic relationships appears to mirror the quality of their other relationships. Adolescents who have had poor-quality relationships with parents and peers are likely to have romantic relationships characterized by low levels of intimacy and commitment (Ha et al., 2010; Oriña et al., 2011; Seiffge- Krenke, Overbeek, & Vermulst, 2010) and by aggression (Stocker & Richmond, 2007; Zimmer-Gembeck, Siebenbruner, & Collins, 2004). It is also believed that adolescents’ working models of relationships with their parents tend to be reflected in their romantic relationships. This belief is sup- ported by the finding that children who were securely attached at age 12 months were more socially competent in elementary school, which predicted more secure relationships with friends at age 16. The security of these friendships, in turn, predicted more positive daily emotional experiences in romantic relationships at ages 20 to 23 and less negative affect in conflict resolution and collaborative tasks with romantic partners ( J. A. Simpson et al., 2007). Related research suggests that individuals who were securely attached in infancy, in contrast to those with inse- cure attachments, rebound better from conflicts with their romantic partners in early adulthood (Salvatore et al., 2011). Thus, romantic relationships appear to be affected in multiple ways by youths’ history of relationships with parents and peers (Rauer et al., 2013). review: Very young children often interact with peers in groups, and dominance hierarchies emerge in these groups by preschool age. By middle childhood, most children belong to cliques of same-gender peers who often are similar in their aggressiveness and orientation toward school. In adolescence, the importance of cliques tends to diminish, and adolescents typically belong to more than one group. The degree of conformity to the norms of the peer group regarding dress, talk, and behavior decreases over the high school years. Nonetheless, ado- lescents often are members of crowds, such as the jocks or brains—that is, groups of peo- ple with similar reputations. Even though adolescents often do not choose what crowd they belong to, belonging to a particular crowd may affect their reputations, their treatment by peers, and their exploration of identities. Peer groups sometimes contribute to the development of antisocial behavior and the use of alcohol and drugs, although children and adolescents may also select peers with problem behaviors that are similar to their own. Membership in a gang is particularly likely to encour- age problem behavior. The degree to which the peer group influences adolescents’ antisocial behavior or drug abuse appears to vary according to family and cultural factors. Involvement in romantic relationships increases with age in adolescence, and youths increasingly select partners based on intimacy, compatibility, and caring rather than on cri- teria such as social status and stylishness. Involvement in romantic relationships often is related to a sense of belonging, high self-esteem, and reduced depressive feelings, but can also lead to involvement in risky behaviors, such as drinking and using drugs, and to feelings of rejection if one partner treats the other poorly. The quality of youths’ romantic relationships tends to mirror the quality of their relationships with parents and friends. Status in the Peer Group As noted in the preceding section, older children and adolescents often are extremely concerned with their peer status: being popular is of great importance, and peer rejection can be a devastating experience. Rejection by peers is associated S T A T U S I N T H E P E E R G R O U P n 533 with a range of developmental outcomes for children, such as dropping out of school and problem behaviors, and these relations can hold independent of any ef- fects of having, or not having, close friends (Gest et al., 2001). Because of the cen- tral role that peer relations play in children’s lives, developmental researchers have devoted a good deal of effort to studying the concurrent and long-term effects as- sociated with peer status. In this section, we will examine children’s status in the peer group, including how it is measured, its stability, the characteristics that determine it, and the long- term implications of being popular with, or being rejected by, peers. Measurement of Peer Status The most common method developmentalists use to assess peer status is to ask children to rate how much they like or dislike each of their classmates. Alterna- tively, they may ask children to nominate some of those whom they like the most and the least, or whom they do or don’t like to play with. The information from these procedures is used to calculate the children’s sociometric status, or peer acceptance—that is, the degree to which the children are liked or disliked by their peers as a group. The most commonly used sociometric system classifies children into one of five groups: popular, rejected, neglected, average, or controversial (see Table 13.3) (Coie & Dodge, 1988). Characteristics Associated with Sociometric Status Why are some children liked better than others? One obvious factor is physical attractiveness. From early childhood through adolescence, attractive children are much more likely to be popular, and are less likely to be victimized by peers, than are children who are unattractive (Langlois et al., 2000; Rosen, Underwood, & Beron, 2011; Vannatta et al., 2009). Athleticism is also related to high peer sta- tus, albeit more strongly for boys than for girls (Vannatta et al., 2009). Further affecting peer status is the status of one’s friends: having popular friends appears to boost one’s own popularity (Eder, 1985; Sabongui, Bukowski, & Newcomb, 1998). Beyond these simple determiners, sociometric status also seems to be affected by a variety of other factors, including children’s social behavior, personality, cognitions about others, and goals when interacting with peers. TABLE 13.3 common Sociometric categories Popular—Children are designated as popular if they receive many positive nominations (e.g., for being liked) and few negative nominations (e.g., for being disliked). Rejected—Children are designated as rejected if they receive many negative nominations and few positive nominations. Neglected—Children are designated as neglected if they are low in social impact—that is, if they receive few positive or negative nominations. These children are not especially liked or disliked by peers; they simply go unnoticed. Average—Children are designated as average if they receive an average number of both positive and negative nominations. Controversial—Children are designated as controversial if they receive many positive and many negative nominations. They are noticed by peers and are liked by a quite a few children and disliked by quite a few others. sociometric status n a measurement that reflects the degree to which children are liked or disliked by their peers as a group 534 n chApter 13 PEER RELATIONSHIPS Popular Children Popular children—those who, in sociometric procedures, are predominantly nomi- nated as liked by peers—tend to have a number of social skills in common. To begin with, they tend to be skilled at initiating interaction with peers and at maintaining positive relationships with others (Rubin et al., 2006). For example, when popu- lar children enter a group of children who are already talking or playing, they first try to see what is going on in the group and then join in by talking about the same topic or engaging in the same activity as the group, rather than drawing unwar- ranted attention to themselves (Dodge et al., 1983; Putallaz, 1983). At a broader level, popular children tend to be cooperative, friendly, sociable, helpful, and sensitive to others, and they are perceived that way by their peers, teachers, and adult observers (Dodge et al., 1997; Lansford et al., 2006; Newcomb, Bukowski, & Pattee, 1993; Rubin et al., 2006). They also regulate themselves well (N. Eisenberg et al., 1993; Kam et al., 2011), are not prone to intense negative emotions, and tend to have a relatively high number of low-conflict reciprocated friendships (Litwack, Wargo Aikins, & Cillessen, 2012). Although popular children often are less aggressive overall than are rejected children (Newcomb et al., 1993), in comparison with children designated as average (i.e., those who receive an average number of both positive and negative nom- inations), they are less aggressive only with respect to aggression related to general- ized anger, vengefulness, or satisfaction in hurting others (Dodge et al., 1990). With respect to assertive aggressiveness, including pushing and fighting, popular children often do not differ from average children (Newcomb et al., 1993). Highly aggressive children may even have high peer acceptance in some special cases, such as among adolescent males (but not females) who perform poorly in school (Kreager, 2007), in peer groups in which the popular members tend to be relatively aggressive (Dijkstra, Lindenberg, & Veenstra, 2008), or in classrooms that have a strong hierarchy in terms of peer status (Garandeau, Ahn, & Rodkin, 2011). On the question of aggression and popularity, it is important to differenti- ate between children who are popular in terms of sociometric, or social-preference, popular (peer status) n a category of sociometric status that refers to children or adolescents who are viewed positively (liked) by many peers and are viewed neg- atively (disliked) by few peers physically attractive children and teens tend to be more popular than their less attrac- tive peers. BL E N D I M A G E S / A G E F O T O S T O C K S T A T U S I N T H E P E E R G R O U P n 535 measures—that is, who are well liked by peers—and those who are perceived by peers as being popular or high status in the group. Although children who are well liked by peers tend not to be particularly aggressive, children who are perceived as having high status in the group—those who are often labeled “popular” by other children and often seen as “cool”—tend to be viewed as above average in aggression and use it to obtain their goals (P. H. Hawley, 2003; Kuryluk, Cohen, & Audley- Piotrowski, 2011; Prinstein & Cillessen, 2003). This association between aggression and perceived popularity, although seen to some degree even in preschool (Vaughn et al., 2003), is quite strong in early adolescence; indeed, high-status individuals, particularly girls, are likely to engage in relational aggression, such as excluding others from the group, withholding friendship to inflict harm, and spreading rumors to ruin a peer’s reputa- tion (Cillessen & Mayeux, 2004; K. E. Hoff et al., 2009; Prinstein & Cillessen, 2003). Especially if they are aware that they are perceived as popular, youth who are perceived as having high status tend to increasingly use relational and physical ag- gression across adolescence, perhaps because they tend to be arrogant and can get away with it (Cillessen & Mayeux, 2004; Mayeux & Cillessen, 2008; A. J. Rose, Swenson, & Waller, 2004). By the middle-school years, children with the reputa- tion of being popular sometimes start to shun less popular peers. As a result, they are considered “stuck-up,” “mean,” and “snobby” and begin to be viewed with am- bivalence by their peers and sometimes even become resented or disliked (Closson, 2009; Mayeux, 2011; Merten, 1997; D. L. Robertson et al., 2010). Rejected Children A majority of rejected children tend to fall into one of two categories: those who are overly aggressive and those who are withdrawn. Aggressive-rejected children According to reports from peers, teachers, and adult observers, 40% to 50% of rejected children tend to be aggressive. These aggressive-rejected children are especially prone to hostile and threatening behav- ior, physical aggression, disruptive behavior, and delinquency (Lansford et al., 2010; Newcomb et al., 1993; S. Pedersen et al., 2007; Rubin et al., 2006). When they are angry or want their own way, many rejected children also engage in relational aggression (Cillessen & Mayeux, 2004; Crick, Casas, & Mosher, 1997; Tomada & Schneider, 1997). Most of the research on the role of aggression in peer status is correlational, so it is impossible to know for certain whether aggression causes peer rejection or results from it. However, some research supports the view that frequent aggressive behavior often underlies rejection by peers. For example, observation of unfamiliar peers getting to know one another has shown that those who are aggressive become rejected over time (Coie & Kupersmidt, 1983). In addition, longitudinal research has shown that children who are aggressive, negative, and disruptive tend to become increasingly disliked by peers across the school year (S. A. Little & Garber, 1995; Maszk, Eisenberg, & Guthrie, 1999). Nonetheless, other research suggests that the experience of rejection may trig- ger or increase children’s aggression. In an experimental study, 5th- and 6th-graders were led to believe that they had been entered in an online popularity contest and had been evaluated by peer judges on the basis of a personal photograph and infor- mation about their preferences and personality traits. They were then presented with their “peers’ ” evaluations—which were actually standardized assessments devised by relational aggression n a kind of aggression that involves excluding others from the social group and attempting to do harm to other people’s relationships; it includes spreading rumors about peers, withholding friendship to inflict harm, and ignoring peers when angry or frus- trated or trying to get one’s own way. rejected (peer status) n a category of sociometric status that refers to children or adolescents who are liked by few peers and disliked by many peers aggressive-rejected children n a cat- egory of sociometric status that refers to children who are especially prone to physical aggression, disruptive behavior, delinquency, and negative behavior such as hostility and threatening others 536 n chApter 13 PEER RELATIONSHIPS the researchers to be either neutral or mostly negative and rejecting. After receiving their evaluations, the participants were given the opportunity to reduce the payments that would be made to the judges and to post negative comments about the judges on the contest’s website. Those youths who were rejected by the judges, compared with those who were not, imposed deeper cuts on judges’ payments and posted more nega- tive comments about them on the website (Reijntjes, Thomaes et al., 2011). Taken together, these and other studies suggest that the relation between peer rejection and youths’ aggression is bidirectional—that aggression predicts more peer rejection over time and that more peer rejection predicts more aggression (Lansford et al., 2010). As you have seen, however, not all aggressive children are rejected by their peers and some are even perceived as popular (Farmer et al., 2011; D. L. Robertson et al., 2010). Aggressive children sometimes develop a network of aggressive friends and are accepted in their peer group (Xue & Meisels, 2004), and some elementary school and preadolescent children who start fights and get into trouble are viewed as “cool” and are central in their peer group (K. E. Hoff et al., 2009; Rodkin et al., 2000, 2006). Many of these children are among those designated as controversial— liked by numerous peers and disliked by numerous others. Withdrawn-rejected children The second group of rejected children includes those who are withdrawn-rejected. These children, who make up 10% to 25% of the rejected category, are socially withdrawn and wary and, according to some re- search, are often timid and socially anxious (Booth-LaForce et al., 2012; Cillessen et al., 1992; Rubin et al., 2006). They frequently are victimized by peers, and many feel isolated and lonely (Booth-LaForce & Oxford, 2008; Rubin, Coplan, & Bowker, 2009; Woodhouse, Dykas, & Cassidy, 2012). Friendlessness, friendship in- stability, and exclusion in 5th grade predict increases in socially withdrawn behav- ior through 8th grade, whereas low peer exclusion in 5th grade predicts a decline in social withdrawal across time (Oh et al., 2008). Thus, as with aggression, social withdrawal may be both a cause and consequence of peer exclusion and rejection. However, not all socially withdrawn children are rejected or socially excluded (Gazelle, 2008; Gazelle & Ladd, 2003). Rather, it is active isolates—withdrawn chil- dren who display immature, unregulated, or angry, defiant behavior such as bullying, boasting, and meanness—who are the most likely to be rejected by their peers. Re- search suggests that children who are withdrawn with peers but are relatively socially competent tend to be merely neglected—that is, they are not nominated as either withdrawn-rejected children n a cat- egory of sociometric status that refers to rejected children who are socially with- drawn, wary, and often timid E LI Z A B E T H C R E W S children who are socially withdrawn because they enjoy being by themselves do not nec- essarily experience rejection from peers. S T A T U S I N T H E P E E R G R O U P n 537 liked or disliked by peers (Harrist et al., 1997). Similarly, children and adolescents who are simply not social and prefer solitary activities may not be especially prone to peer rejection ( J. C. Bowker & Raja, 2011; Coplan & Armer, 2007). Over the course of childhood, withdrawn behavior seems to become a more reli- able predictor of peer rejection. By the middle to late elementary school years, chil- dren who are quite withdrawn stand out, tend to be disliked, and appear to become increasingly alienated from the group as time goes on (Rubin et al., 1998). In some cases, however, children who are not initially socially withdrawn have social isolation forced upon them as they progress through school (A. Bowker et al., 1998). That is, children who are disliked and rebuffed by peers, often because of their disruptive or aggressive behavior, may increasingly isolate themselves from the group even if they initially were not withdrawn (Coie, Dodge, & Kupersmidt, 1990; Rubin et al., 1998). Social cognition and social rejection Rejected children, particularly those who are aggressive, tend to differ from more popular children in their social motives and in the way they process information related to social situations (Lansford et al., 2010). For example, rejected children are more likely than better-liked peers to be motivated by goals such as “getting even” with others or “showing them up” (Crick & Dodge, 1994; Rubin et al., 2006). As discussed in Chapter 9 (pages 357–358), they also are relatively likely to attribute malicious intent to others in negative social situations, even when the intent of others is uncertain or benign (Crick & Dodge, 1994). Rejected children also have more trouble than other children do in finding con- structive solutions to difficult social situations, such as wanting to take a turn on a swing when someone else is using it. When asked how they would deal with such situations, rejected children suggest fewer strategies than do their more popular peers, and the ones they suggest are more hostile, demanding, and threatening (Dodge et al., 2003; Harrist et al., 1997; Rubin et al., 1998). (Box 13.3 discusses programs designed to help rejected children gain peer acceptance.) Perhaps one reason rejected children are more likely to select inappropriate strategies is that their theory of mind is less developed than that of their better-liked peers, and they may therefore have greater difficulty understanding others’ feelings and thoughts (Caputi et al., 2012; see Chapter 7, pages 267–268). Neglected Children As noted earlier, some withdrawn children are categorized as neglected because they are not nominated by peers as either liked or disliked (Booth-LaForce & Oxford, 2008). These children tend to be both less sociable and less disruptive than average children (Rubin et al., 1998) and are likely to back away from peer interac- tions that involve aggression (Coie & Dodge, 1988). Neglected children perceive that they receive less support from peers (S. Walker, 2009; Wentzel, 2003), yet they are not particularly anxious about their social interactions (Hatzichristou & Hopf, 1996; Rubin et al., 1998). In fact, other than being less socially interactive, neglected children display few behaviors that differ greatly from those of many other children (Bukowski et al., 1993; S. Walker, 2009). They appear to be ne- glected primarily because they are simply not noticed by their peers. Controversial Children In some ways, the most intriguing group of children are controversial children, who, as indicated, are liked by numerous peers and disliked by numerous others. Controversial children tend to have characteristics of both popular and rejected neglected (peer status) n a category of sociometric status that refers to chil- dren or adolescents who are infrequently mentioned as either liked or disliked; they simply are not noticed much by peers controversial (peer status) n a cat- egory of sociometric status that refers to children or adolescents who are liked by quite a few peers and are disliked by quite a few others 538 n chApter 13 PEER RELATIONSHIPS Given the difficult and often painful out- comes commonly associated with a child’s being rejected or having few friends, a num- ber of researchers have designed programs to help children in these categories gain acceptance from peers. Their approaches have varied according to what they believe to be the causes of social rejection, but a number of approaches have proved to be useful, at least to some degree. One common approach involves social skills training. The assumption behind this approach is that rejected children lack social skills that promote positive peer rela- tions. These deficits are viewed as occurring at three levels (Mize & Ladd, 1990): 1. Lack of social knowledge—Rejected chil- dren lack social knowledge regarding the goals, strategies, and normative expecta- tions that apply in specific peer contexts. For example, children engaged in a joint activity usually expect a newcomer to the group to blend in slowly and not to begin immediately pushing his or her own ideas or wishes. Lacking an understand- ing of this, aggressive-rejected children are likely to barge in on a conversation or to try to control the group’s choice of activities. In contrast, a withdrawn- rejected child may not know how to start a conversation or contribute to the group’s activities when the opportunity arises. 2. Performance problems—Some rejected children possess the social knowledge required for being successful in vari- ous peer contexts, but they may still act inappropriately because they are unable or unmotivated to use their knowledge to guide their performance. 3. Lack of appropriate monitoring and self- evaluation—To behave in a way that is consistent with the interests and actions of their peers, children need to moni- tor their own and others’ social behav- ior. Such monitoring requires them to accurately interpret social cues regarding what is occurring, what others are feeling and thinking, and how their own behav- ior is being perceived. Rejected children often cannot engage in such monitoring and thus cannot modify their behavior in appropriate ways. To help children overcome such defi- cits, some social-skills training programs teach children to pay attention to what is going on in a group of peers and help them develop skills related to participating with peers. Interventions may include coaching and rehearsing children on how to start a conversation with an unfamiliar peer, how to compliment a peer, how to smile and offer help, and how to take turns and share materials (Oden & Asher, 1977). In other interventions, the emphasis is primarily on teaching children to think about alternative ways to achieve a goal, evaluate the con- sequences of each alternative, and then select an appropriate strategy. Children may be asked to think about or act out a situa- tion in which they are excluded or teased by peers and to come up with various strate- gies for handling the situation. The children are then helped to evaluate the strategies and to understand the specific costs and benefits of each (e.g., Coleman, Wheeler, & Webber, 1993). Recent forms of this sort of program are often multifaceted, including such components as communication skills, anger management, and training in per- spective taking (Reid, Webster-Stratton, & Hammond, 2007; Webster-Stratton, Reid, & Stoolmiller, 2008). Their primary focus is on helping children to better under- stand and communicate about their own and others’ emotions and to regulate their behavior (Domitrovich, Cortes, & Greenberg, 2007; Izard et al., 2008; P. C. McCabe & Altamura, 2011), although training in social-skill strategies also usually occurs to some degree. The general assumption underlying these programs is that children act in more appropriate ways and, consequently, are better liked if their behavior takes into account the feelings of others and is modu- lated in a manner that is both sensitive and socially appropriate to those feelings. A notable example of this approach is the PATHS (Promoting Alternative Thinking Strategies) curriculum, in which children learn to identify emotional expressions (using pictures, for example) and to think about the causes and consequences of different ways of expressing emotions (Domitrovich et al., 2007, 2010). In addition, the program pro- vides children with opportunities to develop conscious strategies for self-control through verbal mediation (self-talk) and practicing ways to self-regulate. The PATHS approach is illustrated by the Control Signals Poster (CSP), which, like the Turtle Technique dis- cussed in Chapter 1, is designed to remind children how to deal with troubling social situations: The CSP is modeled after a traffic signal, with red, yellow, and green lights. The red light signals children to “Stop—Calm Down.” Here, youth are instructed that as challenging so- cial situations occur, they should first “take a long deep breath,” calm down, and “say the problem and how they feel.” The yellow light signals children to “Slow Down—Think.” Here, youth make a plan by considering possible solutions and then selecting the best option. Finally, the green light signals children to “Go—Try My Plan.” Below the illustration of the stoplight are the words “Evaluate—How Did My Plan Work?” Students may then formulate and try new plans if necessary. (Riggs et al., 2006, p. 94) Programs like this one tend to be suc- cessful in fostering knowledge about emo- tions, self-regulation, prosocial behavior, and social competence—and sometimes in reducing social withdrawal and aggres- sion as well (e.g., Bierman et al., 2010; Domitrovich et al., 2007; Izard et al., 2008; Riggs et al., 2006). Such improve- ments have been found especially for chil- dren with numerous problem behaviors and for children in disadvantaged schools (Bierman et al., 2010; Greenberg et al., 1995). The increases in social competence that often result as a consequence of par- ticipation in such an intervention would be expected to promote children’s social sta- tus, although this issue usually has not been specifically tested. BOX 13.3: applications FOSTERING CHILDREN’S PEER ACCEPTANCE S T A T U S I N T H E P E E R G R O U P n 539 children (Rubin et al., 1998). For example, they tend to be aggressive, disruptive, and prone to anger, but they also tend to be cooperative, sociable, good at sports, and humorous (Bukowski et al., 1993; Coie & Dodge, 1988). In addition, they are very socially active and tend to be group leaders (Coie et al., 1990). At the same time, controversial children tend to be viewed by peers as arrogant and snobbish (Hatzichristou & Hopf, 1996), which could explain why they are disliked by some peers even if they are perceived as having high status in the peer group (D. L. Robertson et al., 2010). Stability of Sociometric Status Do popular children always remain at the top of the social heap? Do rejected chil- dren sometimes become better liked? In other words, how stable is a child’s socio- metric status in the peer group? The answer to this question depends in part on the particular time span and sociometric status that are in question. Over relatively short periods such as weeks or a few months, children who are popular or rejected tend to remain so, whereas children who are neglected or contro- versial are likely to acquire a different status (Asher & Dodge, 1986; X. Chen, Rubin, & B. Li, 1995; Newcomb & Bukowski, 1984; S. Walker, 2009). Over longer periods, children’s sociometric status is more likely to change. In one study in which children were rated by their peers in 5th grade and again 2 years later, only those children who had initially been rated average maintained their status overall, whereas nearly two-thirds of those who had been rated popular, rejected, or controversial received a different rating later on (Newcomb & Bukowski, 1984). Over time, sociometric stability for rejected children is generally higher than for popular, neglected, or con- troversial children (Harrist et al., 1997; Parke et al., 1997; S. Walker, 2009) and may increase with the age of the child (Coie & Dodge, 1983; Rubin et al., 1998). Cross-Cultural Similarities and Differences in Factors Related to Peer Status Most of the research on behaviors associated with sociometric status has been con- ducted in the United States, but findings similar to those discussed here have been obtained in a wide array of cross-cultural research. In countries ranging from Canada, Italy, Australia, the Netherlands, and Greece to Indonesia, Hong Kong, Japan, and China, for example, socially rejected chil- dren tend to be aggressive and disruptive; and, in most countries, popular (i.e., well-liked) children tend to be described as prosocial and as having lead- ership skills (Attili, Vermigli, & Schneider, 1997; Chung-Hall & Chen, 2010; D. C. French, Setiono, & Eddy, 1999; Gooren et al., 2011; Hatzichristou & Hopf, 1996; Kawabata, Crick, & Hamaguchi., 2010; D. Schwartz et al., 2010; Tomada & Schneider, 1997; S. Walker, 2009; Y. Xu et al., 2004). Similar cross-cultural parallels have been found with regard to withdrawal and rejection. Various studies done in Germany, Italy, and Hong Kong, for example, have shown that, as in the United States, children who are well liked tend to have similar characteristics in many cultures, as do children who are rejected by their peers. JA N E T W IS H N E T S K Y / C O R B IS social-skills training n training pro- grams designed to help rejected children gain peer acceptance; they are based on the assumption that rejected children lack important knowledge and skills that promote positive interaction with peers 540 n chApter 13 PEER RELATIONSHIPS withdrawal becomes linked with peer rejection in preschool or elementary school (Asendorpf, 1990; Attili et al., 1997; Casiglia, Lo Coco, & Zappulla, 1998; D. A. Nelson et al., 2010; D. Schwartz et al., 2010). Research has also demonstrated that there are certain cultural and historical differences in the characteristics associated with children’s sociometric status. One notable example involving both types of differences is the status associ- ated with shyness among Chinese children. In studies conducted in the 1990s, Chinese children who were shy, sensitive, and cautious, or inhibited in their be- havior were—unlike their inhibited or shy Western counterparts—viewed by teachers as socially competent and as leaders, and they were liked by their peers ((X. Chen, Rubin, & B. Li, 1995; X. Chen, Rubin, & Z.-y. Li, 1995; X. Chen et al., 1999; X. Chen, Rubin, & Sun, 1992). A probable explanation for this differ- ence is that Chinese culture traditionally values self-effacing, withdrawn behav- ior, and Chinese children are encouraged to behave accordingly (Ho, 1986). In contrast, because Western cultures place great value on independence and self-assertion, withdrawn children in these cultures are likely to be viewed as weak, needy, and socially incompetent. However, Chen found that since the early 1990s, shy, reserved behavior in Chinese elementary school children has become increas- ingly associated with lower levels of peer acceptance, at least for urban children (X. Chen, Chang et al., 2005). Chen argues that the economic and political changes in China in the past decade have been accompanied by an increased valuing of assertive, less inhibited behavior. For children from rural areas who have had only limited exposure to the dramatic cultural changes in China in recent years, shyness is associated with high levels of both peer liking and disliking, albeit more to lik- ing; thus, for groups somewhat less exposed to cultural changes, shyness is viewed with some ambivalence by peers (X. Chen, Wang, & Cao, 2011; X. Chen, Wang, & Wang, 2009). In addition, for the rural children, being unsociable—that is, uninterested in social interaction—is associated with peer rejection (X. Chen et al., 2009), whereas among North American children it often is not, at least for younger children. Thus, culture and changes in culture appear to affect children’s evaluations of what is desirable behavior. Peer Status as a Predictor of Risk Having an undesirable peer status has been associated with a variety of short-term and long-term risks and negative outcomes for children, including inferior aca- demic performance, loneliness, delinquency, and poor adjustment. Academic Performance Research in a variety of regions, including North America, China, and Indonesia, indicates that rejected children, especially those who are aggressive, are more likely than their peers to have academic difficulties (X. Chen et al., 2011; Chung-Hall & Chen, 2010; D. C. French et al., 1999; Véronneau et al., 2010; Wentzel, 2009). In particular, they have higher rates of school absenteeism (DeRosier, Kupersmidt, & Patterson, 1994) and lower grade-point averages (Wentzel & Caldwell, 1997). Those who are aggressive are especially likely to be uninterested in school and to be viewed by peers and teachers as poor students (Hymel, Bowker, & Woody, 1993; Wentzel & Asher, 1995). Longitudinal research, conducted mostly in the United States, indicates that students’ classroom participation is lower during periods in which they are S T A T U S I N T H E P E E R G R O U P n 541 rejected by peers than during periods when they are not, and that the tendency of rejected children to do relatively poorly in school worsens across time (Coie et al., 1992; Ladd, Herald-Brown, & Reiser, 2008; Ollendick et al., 1992). In one study that followed children from 5th grade through the high school years, rejected children were much more likely than other children, especially popular children, to be required to repeat a grade or to be suspended from school, to be truants, or to drop out (Kupersmidt & Coie, 1990) (Figure 13.2). They were also more likely to have difficulties with the law—in many cases, no doubt, deepening their aca- demic difficulties. All told, approximately 25% to 30% of rejected children drop out of school, compared with approximately 8% or less of other children (Parker & Asher, 1987; Rubin et al., 1998). Problems with Adjustment Children who are rejected in the elementary school years—especially aggressive- rejected boys—are at risk for increases in externalizing symptoms such as aggres- sion, delinquency, hyperactivity and attention-deficit disorders, conduct disorder, and substance abuse (Criss et al., 2009; Lansford et al., 2010; Ollendick et al., 1992; Sturaro et al., 2011; Vitaro et al., 2007). In one longitudinal study that fol- lowed more than 1000 U.S. children from 3rd to 10th grade (Coie et al., 1995), boys and girls who were assessed as rejected in 3rd grade were, according to par- ent reports, higher than their peers in externalizing symptoms 3 years and 7 years later. In addition, aggressive boys (both rejected and nonrejected) increased in parent-reported externalizing symptoms between grades 6 and 10, whereas other boys did not; and by 10th grade, aggressive-rejected boys themselves reported an average of more than twice the number of symptoms reported by all other boys (Figure 13.3). Other research provides evidence that peer rejection may also be associated with internalizing problems such as loneliness, depression, withdrawn behavior, and obsessive-compulsive behavior (Gooren et al., 2011; Prinstein et al., 2009), even 10 to 40 years later (Modin, Östberg, & Almquist, 2011). In the longitudinal study of more than 1000 children mentioned above, girls and boys who were rejected in 3rd grade were, as reported by parents, higher than their peers in internalizing Retained Truant Suspended Dropped out Problems with police 70 60 50 40 30 20 10 0 P er ce n ta ge Nonspecific Popular Sociometric status group Average Neglected Rejected FIGURE 13.2 the relation of children’s sociometric status to academic and behavioral problems children’s sociometric status is related to their future problem behaviors. rejected children are far more likely to be held back in, or suspended from, school; to be truants; to drop out; and to have problems with the police. (Adapted from Kupersmidt & coie, 1990) Aggressive-rejected 6 10 8 25 20 15 10 5 0 N u m b er o f sy m p to m s Rejected-nonaggressive Nonrejected-aggressive Nonrejected-nonaggressive Grade FIGURE 13.3 rates of parent-reported externalizing symptoms in adolescent males as a function of 3rd-grade rejection and aggression According to parent reports, boys who were assessed as rejected in 3rd grade showed more externalizing symptoms than did their peers years later. Aggressive boys (both rejected and nonrejected) showed an increase in parent-reported external- izing symptoms between grades 6 and 10, whereas other boys did not; by 10th grade, aggressive-rejected boys had an especially high number of externalizing symptoms. (Adapted from coie et al., 1995) 542 n chApter 13 PEER RELATIONSHIPS symptoms by 6th grade and 10th grade. Moreover, aggressive-rejected boys them- selves reported a marked increase in internalizing symptoms from 6th to 10th grade, whereas all other boys reported a drop in these symptoms (Figure 13.4). Aggressive-rejected girls were viewed by parents as most prone to internalizing problems by grade 10. Thus, both boys and girls who were assessed as rejected in 3rd grade—especially if they also were aggressive—were at risk for developing in- ternalizing problems years later (Coie et al., 1995). Also at risk for internalizing problems in Western cultures are children who are very withdrawn but nonaggressive with their peers. As you have seen, although these children tend to become rejected by the middle to late elemen- tary school years, they are generally not at risk for the behavioral problems that aggressive-rejected children often experience. However, a consistent pattern of social withdrawal, social anxiety, and wariness with familiar people, including peers, is associated with symptoms such as depression, low self-worth, and lone- liness in childhood and into early adulthood (Hoza et al., 1995; S. J. Katz et al., 2011; Rubin et al., 2009). Children who are socially withdrawn amid familiar peers may differ in impor- tant ways from their peers even in adulthood. In a longitudinal study of American children born in the late 1920s, boys who were rated by their teachers as reserved and unsociable were less likely to have been married and to have children than were less reserved boys. They also tended to begin their careers at later ages, had less suc- cess in their careers, and were less stable in their jobs. Reserved men who were late in establishing stable careers had twice the rate of divorce and marital separation by midlife as did their less reserved peers. In contrast, reserved girls were more likely than their less reserved peers to have a conventional lifestyle of marriage, parenthood, and homemaking rather than working outside the home. Thus, a reserved style of interaction at school during childhood was associated with more negative outcomes for men than for women, perhaps because a reserved style was more compatible with the feminine home- maker role of the times than with the demands of achieving outside the home (Caspi, Elder, & Bem, 1988). A final group of rejected children who may be especially at risk for loneliness and other internalizing problems is victimized children, who are targets of their peers’ aggression and demeaning behavior. Although the sequence of events is not entirely clear, it appears that children in this group are more likely to be rejected first and then victimized rather than the reverse (Hanish & Guerra, 2000a; D. Schwartz et al., 1999). Victimized children tend to be aggressive, as well as withdrawn and anxious (Barker et al., 2008; D. Schwartz et al., 1998; J. Snyder, Brooker et al., 2003; Tom et al., 2010), and the relation between victimization and aggression appears to be bidirectional (Reijntjes et al., 2011; van Lier et al., 2012). Aggression sometimes appears to elicit victimization by peers (Barker et al., 2008; Kawabata et al., 2010). Other factors might also contribute to victimization. For example, immigrant children are more likely to be victimized than are peers who are part of the major- ity group, likely because they are seen as different (Strohmeier, Kärnä, & Salmi- valli, 2011; von Grünigen et al., 2010). In addition, hereditary factors associated with aggression appear to predict peer victimization, suggesting that tempera- mental or other personal characteristics may increase the likelihood of children becoming both aggressive and victimized (Brendgen et al., 2011). For example, low self- regulation is related to both aggression and peer victimization (N. Eisenberg, Sallquist et al., 2009; Iyer et al., 2010) and may contribute to both. Aggressive-rejected Nonrejected-aggressive Rejected-nonaggressive and Nonrejected-nonaggressive 7 6 5 4 3 2 1 0 6 10 8 N u m b er o f sy m p to m s Grade FIGURE 13.4 rates of boys’ self- reported internalizing symptoms as a function of 3rd-grade rejection and aggression Aggressive-rejected boys’ reports of internalizing problems increased from 6th to 10th grade, whereas such reports decreased over the same period for all other boys. (Adapted from coie et al., 1995) victimized (peer status) n with respect to peer relationships, this term refers to children who are targets of their peers’ aggression and demeaning behavior S T A T U S I N T H E P E E R G R O U P n 543 Unfortunately, peer victimization is not an uncommon event and can begin quite early. In one study in the United States, approximately one-fifth of kindergartners were repeatedly victimized by peers (Kochenderfer & Ladd, 1996). Over time, vic- timization by peers likely increases children’s aggression, withdrawal, depression, and loneliness (Nylund et al., 2007; D. Schwartz et al., 1998), leading to hanging out with peers who are engaged in deviant behaviors (Rudolph et al., 2013), as well as problems at school and absenteeism ( Juvonen, Nishina, & Graham, 2000; Kochenderfer & Ladd, 1996; Nakamoto & Schwartz, 2010). Although the rate of victimization generally appears to be lower among older children (Olweus, 1994), peer victimization is a serious problem that warrants concern, especially since the same children tend to be victimized again and again (Hanish & Guerra, 2000b). Paths to Risk Clearly, children who are rejected by peers are at risk for academic and adjust- ment problems. The key question is whether peer rejection actually causes prob- lems at school and in adjustment, or whether children’s maladaptive behavior (e.g., aggression) leads to both peer rejection and problems in adjustment (Parker et al., 1995; L. J. Woodward & Fergusson, 1999). Although conclusive evidence is not yet available, findings suggest that peer status and the quality of children’s social behavior have partially independent effects on subsequent adjustment (Coie et al., 1992; DeRosier et al., 1994). Moreover, early maladjustment, such as internalizing problems, may contribute to both future maladaptive behavior (e.g., aggression) and peer victimization, which in turn may lead to more internalizing problems over time (Leadbeater & Hoglund, 2009). Thus, it is likely that there are com- plex bidirectional relations among children’s adjustment, social competencies, and peer acceptance (Boivin et al., 2010; Fergusson, Woodward, & Horwood, 1999; Lansford et al., 2010; Obradović & Hipwell, 2010). Once children are rejected by peers, they may be denied opportunities for posi- tive peer interactions and thus for learning social skills. Moreover, cut off from desirable peers, they may be forced to associate with other rejected children, and rejected children may teach one another, and mutually reinforce, deviant norms and behaviors. The lack of social support from peers also may increase rejected chil- dren’s vulnerability to the effects of stressful life experiences (e.g., poverty, parental conflict, divorce), negatively influencing their social behavior even further, which in turn affects both their peer status and adjustment. review: Children’s sociometric status is assessed by peers’ reports of their liking and disliking of one another. On the basis of such reports, children typically have been classified as popular, rejected, average, neglected, or controversial. Well-liked, popular children tend to be attractive, socially skilled, prosocial, well regu- lated, and low in aggression that is driven by anger, vengefulness, or satisfaction in hurting others. However, some children who are viewed as popular by their peers are aggressive and not especially well-liked. Some rejected children tend to be relatively aggressive, disruptive, and low in social skills; they also tend to make hostile attributions about others’ intentions and have trouble dealing with difficult social situations in a constructive manner. Withdrawn children who are aggressive and hostile as well are also rejected by peers by kindergarten age. In contrast, most children who are withdrawn from their peers but are not hostile and aggressive are at somewhat less risk, although they sometimes become rejected later in elementary school. 544 n chApter 13 PEER RELATIONSHIPS Neglected children interact less frequently with peers than do children who are average in sociometric status, and they display relatively few behaviors that differ greatly from those of many other children. Controversial children display characteristics of both popular and rejected children and tend to be very socially active. Children who are neglected or contro- versial, unlike rejected children, are particularly likely to change their status, even over short periods. Rejection by peers in childhood—especially rejection due to aggression—predicts rela- tively high levels of subsequent academic problems and externalizing behaviors. Rejected children also tend to become more withdrawn and are prone to loneliness and depression. It is likely that children’s maladaptive behavior as well as their low status with peers contribute to these negative developmental outcomes. The Role of Parents in Children’s Peer Relationships Cliff is having a hard time . . . he just doesn’t have any good friends, says he has no one to do things with . . . he’s just not part of the gang. . . . I hate to see him having troubles with the other kids—I keep wondering if I should do something about it, or if he just has to sort it out hisself. . . . And it reminds me of my troubles at school. (quoted in Dunn, personal communication) The speaker, the mother of 8-year-old Cliff, not only worries about Cliff ’s problems with his peers but also feels that she may have contributed to them—a common reaction of parents of lonely and rejected children. The idea that par- ents influence children’s ability to relate to peers has a long history, beginning with Freud’s emphasis on the importance of the mother–child relationship as a foundation for later personality development and interpersonal relationships. Moreover, attachment theorists (see Chapter 11) as well as social learning theo- rists (see Chapter 9) have asserted that early parent–child interactions are linked to children’s peer interactions at an older age. It also seems likely that children’s ongoing relationships with their parents can affect their relationships with their peers. Relations Between Attachment and Competence with Peers Attachment theory maintains that whether a child’s attachment to the parent is secure or insecure affects the child’s future social competence and the quality of the child’s relationships with others, including peers. Attachment the- orists have suggested that a secure attachment between parent and child promotes competence with peers in at least three ways (Elicker, Englund, & Sroufe, 1992). First, children with a secure attachment develop positive social expectations. They are thus inclined to interact readily with other children and expect these interactions to be positive and rewarding. Second, because of their experience with a sensitive and responsive caregiver, they develop the foundation for understanding reciprocity in relationships. Consequently, they learn to give and take in relationships and to be empathic to others. Finally, children who are securely attached are likely to be confident, enthusiastic, and emotion- ally positive—characteristics that are attractive to other children and that facilitate social interaction. children who have secure attachment rela- tionships with their parents tend to develop better social skills than do their peers who are not securely attached. S W E E T N O V E M B E R S T U D IO / S H U T T E R S T O C K T H E R O L E O F P A R E N T S I N C H I L D R E N ’ S P E E R R E L A T I O N S H I P S n 545 Conversely, attachment theorists argue, an insecure attachment is likely to impair a child’s competence with peers. If parents are rejecting and hostile or neglectful, young children are likely to become hostile themselves and to expect negative behavior from other people. They may be predisposed to perceive peers as hostile and, consequently, are likely to be aggressive toward them. These chil- dren may also expect rejection from other people and may try to avoid experi- encing it by withdrawing from peer interaction (Furman et al., 2002; Renken et al., 1989). There is a good deal of evidence to support these theoretical views. Children who are not securely attached do, in fact, tend to have difficulties with peer rela- tionships. Toddlers and preschoolers who were insecurely attached as infants tend to be aggressive, whiny, socially withdrawn, and low in popularity in elementary school (Bohlin, Hagekull, & Rydell, 2000; Burgess et al., 2003; Erickson, Sroufe, & Egeland, 1985). Throughout childhood, these children, in comparison with securely attached children, express less positive emotion with peers, as well as less sympathy and prosocial behavior, and they demonstrate poorer skills in resolving conflicts (Elicker et al., 1992; Fox & Calkins, 1993; Kestenbaum, Farber, & Sroufe, 1989; Panfile & Laible, 2012; Raikes & Thompson, 2008). Securely attached children, on the other hand, tend to exhibit positive emo- tions and good social skills and, not surprisingly, tend to have high-quality friend- ships and to be relatively popular with peers—both as preschoolers (LaFreniere & Sroufe, 1985; McElwain, Booth-LaForce, & Wu, 2011) and in elementary school and adolescence (Granot & Mayseless, 2001; Kerns, Klepac, & Cole, 1996; B. H. Schneider, Atkinson, & Tardif, 2001; see Chapter 11). Even in late child- hood and early adolescence, children with more and higher-quality (e.g., more intimate and supportive) friendships tend to be those with a history of a secure attachment (Dwyer et al., 2010; Freitag et al., 1996; B. H. Schneider et al., 2001; J. A. Simpson et al., 2007). Some recent research suggests that the security of attachment with fathers may be especially important for the quality of children’s and adolescents’ friendships (e.g., Doyle, Lawford, & Markiewicz, 2009; Verissimo et al., 2011). Thus, security of the parent–child relationship is linked with quality of peer relationships. This link probably arises from both the early and the continuing effect that parent–child attachment has on the quality of social behavior, as well as their working models of relationships (Shomaker & Furman, 2009). However, it is also possible that the individual characteristics of each child, such as sociability, influence both the quality of attachments and the quality of his or her relation- ships with peers. Quality of Ongoing Parent–Child Interactions and Peer Relationships Ongoing parent–child interactions are associated with peer relations in much the same way that attachment patterns are. For example, socially competent, popular children tend to have mothers who are warm in general, discuss feelings with them, and who use warm control, positive verbalizations, reasoning, and explanations in their approach to parenting (C. H. Hart et al., 1992; Kam et al., 2011; McDowell & Parke, 2009; Updegraff et al., 2010). Research that has investigated ongoing father–child interactions has found that they, too, can play a role in children’s peer relationships. For example, fathers’ warmth and expression of positive rather than negative emotion with their children has been linked to the positivity of children’s 546 n chApter 13 PEER RELATIONSHIPS interactions with close friends in the preschool years (Kahen, Katz, & Gottman, 1994; Youngblade & Belsky, 1992) and to children’s peer acceptance in elementary school (McDowell & Parke, 2009). Overall, research in this area suggests that when the family is generally char- acterized by a warm, involved, and harmonious family style, young children tend to be sociable, socially skilled, liked by peers, and cooperative in child care (R. Feldman & Masalha, 2010). These associations may occur because such parent- ing fosters children’s self-regulation (Eiden et al., 2009; N. Eisenberg, Zhou et al., 2005; Kam et al., 2011). In contrast, parenting that is characterized by harsh, au- thoritarian discipline and low levels of child monitoring is often associated with children’s being unpopular and victimized (Dishion, 1990; Duong et al., 2009; C. H. Hart, Ladd, & Burleson, 1990; Ladd, 1992). In considering findings such as these, it is generally assumed that quality of par- enting influences the degree to which children behave in socially competent ways, which in turn affects whether children are accepted by peers. But as in the case of attachment, it is difficult to prove that quality of parenting actually has a causal in- fluence on children’s social behavior with peers. As we noted in Chapter 12, it may be that children who are aggressive and disruptive because of constitutional factors (e.g., heredity, prenatal influences) elicit both negative parenting and negative peer responses (Rubin et al., 1998); or it may be that both harsh parenting and the chil- dren’s negative behavior with peers are due to heredity. The most likely possibility is that the causal links are bidirectional—that parents’ behavior affects their children’s social competence and vice versa—and that both environmental and biological fac- tors play a role in the development of children’s social competence with peers. Parental Beliefs Parents of socially competent children think about parenting and their children somewhat differently than do parents of children who have low social compe- tence. For one thing, they are more likely to believe that they should play an active role in teaching their children social skills and in providing them with opportu- nities for peer interaction. They also tend to believe that when their children dis- play inappropriate or maladaptive behavior with a peer (e.g., aggression, hostility, social withdrawal), it is because of the circumstances of the specific situation, such as a provocation by the peer or a mutual misunderstanding. In contrast, parents of less socially competent children tend to believe that when their children behave in socially inappropriate ways, it is because of something in their children’s nature and that it would thus be very hard to alter such behavior (Rubin et al., 2006). In other words, they tend to believe that their children “were born that way.” Of course, it is difficult to know the degree to which parents’ beliefs about their children’s social competencies are based on realistic perceptions of their offspring or on their own belief systems and personal history (such as the troubles Cliff ’s mother experienced when she was a schoolchild). Gatekeeping and Coaching Other dimensions of parent–child interactions may influence children’s com- petencies in peer relationships. Two of the more salient ones are parents’ gate- keeping role in their children’s social life and their coaching of their children in social skills. T H E R O L E O F P A R E N T S I N C H I L D R E N ’ S P E E R R E L A T I O N S H I P S n 547 Gatekeeping As noted in Chapter 12, parents, especially those of young children, act as gate- keepers, controlling where their children go, with whom they interact, and how much time they spend with peers doing various activities. However, some parents are more thoughtful and active in this role than are others (Mounts, 2002). Pre- schoolers whose parents arrange and oversee opportunities for them to interact with peers tend to be more positive and social with peers, have a larger and more stable set of play partners, and more easily initiate social interactions with peers than do other children—so long as their parents are not overly controlling in this gatekeeping role (Ladd & Golter, 1988; Ladd & Hart, 1992). Similarly, elementary school children whose parents allow them to engage in numerous social activities in the neighborhood and extracurricular activities at school are more socially com- petent and liked by peers (McDowell & Parke, 2009). In adolescence, gatekeeping may be affected by parents’ cultural orientation. For example, in Mexican American families, parents who had a stronger orien- tation toward Mexican culture and the traditional Mexican value of familism— which emphasizes closeness in the family, family obligations, and consideration of the family in making decisions—placed more restrictions on adolescents’ peer relationships than did parents whose orientation was less traditional. They were also more likely to restrict their adolescents’—especially a daughter’s—contact with peers if the adolescent reported associating with deviant peers (Updegraff et al., 2010). Coaching Preschool children tend to be more socially skilled and more likely to be accepted by peers if their parents effectively coach them on how to interact with unfamiliar peers (Laird et al., 1994; McDowell & Parke, 2009). Mothers of accepted children tend to teach their children group-oriented strategies for gaining entry into a group parents may contribute to their children’s development of social competence by arranging opportunities for their children to interact with peers. A N N A M O LL E R / G E T T Y I M A G E S 548 n chApter 13 PEER RELATIONSHIPS of peers: they may make suggestions about what to say when entering the group, for example, or they may discourage the child from disrupting the group’s current activities. In contrast, mothers of children who are low in sociometric status often try to direct the group’s activity themselves or urge their child to initiate activities that are inconsistent with what the group is currently doing (Finnie & Russell, 1988; A. Russell & Finnie, 1990). Children may also benefit in their peer relations when their parents provide emotion coaching—that is, explanations about the acceptability of emotions and how to appropriately deal with them (L. F. Katz, Maliken, & Stettler, 2012). Chil- dren whose parents use high levels of emotion coaching are, for example, more likely to use appropriate conflict-avoidance strategies, such as laughter, to deflect teasing, and they are less likely to display socially inappropriate behaviors when dealing with peers’ provocations (L. F. Katz, Hunter, & Klowden, 2008). Some evidence suggests that a fairly high level of parental advice giving is sometimes associated with low levels of children’s social competence and peer acceptance; but, in part, this may be because parents are more likely to try to help when their children are experiencing a high level of problems (McDowell & Parke, 2009). It is likely that coaching needs to be provided in a sensitive, skilled manner to be effective; that is, it should convey clear, useful information about others’ feelings and behavior, along with strategies for dealing with them, and it should be pre- sented in a way that does not overwhelm children or derogate them. For reasons that are not yet clear, mothers’ coaching may be especially important for enhanc- ing girls’ social skills (Pettit et al., 1998). Family Stress and Children’s Social Competence As discussed in Chapter 12 (page 480), parents who are preoccupied and distressed by problems related to poverty are more likely to be negative and less likely to be warm and supportive and to monitor their children’s behavior (Lengua, Honorado, & Bush, 2007; McLoyd, 1998). Thus, it is not surprising that children from fami- lies with fewer economic resources and higher levels of stress (e.g., unemploy- ment, health problems) exhibit less social competence, have fewer friends, and are more likely than other children to be rejected by their peers (Brophy-Herb et al., 2007; Criss et al., 2002; Dishion, 1990; C. J. Patterson et al., 1992). For example, in a longitudinal study, elementary school children from low-income families were considerably more likely to be rejected than were children from middle-class fami- lies (boys also were rejected more than girls; see Figure 13.5). It is likely that the effects of poverty and stress on parenting are reflected in children’s compromised social competence. review: Although differences in children’s social behavior likely are based in part on constitutional factors that influence temperament and personality, parents appear to influence children’s competence with peers. Attachment theorists have suggested that a secure attachment between parent and child promotes peer competence because securely attached children develop positive social expectations, the foundation for understanding reciprocity in relation- ships, and a sense of self-worth and self-efficacy. In fact, securely attached children tend to be more positive in their behavior and affect, more socially skilled, and better liked than insecurely attached children. Ongoing parent–child interactions show similar associations with peer relations. Middle Income level Girls Low 30 25 20 15 10 5 0 P er ce n t re je ct ed Boys FIGURE 13.5 percentages of children rejected by peers as a function of gender and family income As can be seen in these data from a longitudinal study, ele- mentary school children from families with low incomes are considerably more likely to be rejected than are children from middle- class families. (Adapted from c. J. patterson et al., 1992) chapter summary: What Is Special About Peer Relationships? n Theorists such as Piaget, Vygotsky, and Sullivan have argued that the equality, reciprocity, cooperation, and intimacy that characterize many peer relationships enhance children’s ability to reason and their concern for others. Friendships n Consistent with theorists’ arguments, peers (especially friends) provide intimacy, support, and rich opportunities for the devel- opment of play and for exchange of ideas. n Even very young children prefer some children over others. Toddlers engage in more complex and cooperative play with friends than with nonfriends, and those who engage in such play exhibit more positive and social behavior with peers when they are older. n As children grow, friends rely on one another and increasingly provide a context for self-disclosure and intimacy. Adolescent friends, more than younger friends, use friendship as a context for self-exploration, personal problem solving, and as a source of honest feedback. n Children’s conceptions of friends change with age. Young children define friendship primarily on the basis of actual activities with their peers. With age, issues such as loyalty, mutual understanding, trust, cooperative reciprocity, and self- disclosure become important components of friendship. n As was suggested by Piaget, Vygotsky, and Sullivan, friends provide emotional support; validation or confirmation of the legitimacy of one’s own thoughts, feelings, and worth; and opportunities for the development of important social and cognitive skills. n Having friends is associated with positive developmental outcomes, such as social competence and adjustment. How- ever, friends also may have negative effects on children if they engage in problematic behaviors such as violence or substance abuse. n Intervention programs can be helpful in teaching children social skills. One common approach, social-skills training, involves teaching children skills related to three types of defi- cits: lack of social knowledge, problems in performing appro- priate behaviors, and a lack of appropriate monitoring and self-evaluation. Many recent programs include procedures to foster children’s understanding and communication of emotion and their self-regulation. n Children tend to become friends with peers who are similar in age, sex, and race, and who are similar in behaviors such as aggression, sociability, and cooperativeness. n The degree to which adults encourage children to play with unrelated peers varies greatly in different cultures, as does the degree to which parents expect their children to develop social skills with peers (e.g., negotiating, taking initiative, standing up for their rights). In addition, the hours children spend with unrelated peers varies considerably across cultures. Peers in Groups n The size of very young children’s playgroups increases with age, and dominance hierarchies emerge by preschool age. n By middle childhood, most children belong to cliques of same- sex peers, and members of cliques often are similar in their aggressiveness and orientation toward school. Membership in these cliques is not very stable over time. n In adolescence, the importance of cliques tends to diminish, and adolescents tend to belong to more than one group. With increasing age, adolescents are not only more autonomous but also tend to look more to individual relationships rather than to a social group to fulfill their social needs. Nonetheless, ado- lescents often are members of crowds. In adolescence, girls and boys associate with one another more with increasing age, both as members of social groups and in dyadic relationships. n In some circumstances, the peer group may contribute to the development of antisocial behavior, alcohol consumption, and substance use, although youths may also actively seek out peers who engage in similar levels of these behaviors. Status in the Peer Group n On the basis of their sociometric ratings, children typically have been classified as popular, rejected, neglected, average, or controversial. n Children’s status in the larger peer group varies as a function of their social behavior and thinking about their social interac- tions, as well as their physical attractiveness. Parents can also influence their children’s competence with peers through their beliefs, their role as gatekeepers, and the social behaviors they teach their children. It is probable that the causal links between quality of parenting and children’s social competence are bidirectional and that both environmental (e.g., parenting, poverty) and biological factors play a role in the development of children’s social competence with peers. C H A P T E R S U M M A R Y n 549 550 n chApter 13 PEER RELATIONSHIPS Critical Thinking Questions 1. What are some of the ways in which same-aged peer rela- tionships and relationships with older or younger siblings might differ? On what dimensions are they typically the same? What might Piaget and Vygotsky say about the dif- ferent costs and benefits of interactions with same-aged friends and differently aged siblings? 2. What procedures and methods might someone use to assess which 2-year-old playmates in a group are close friends? How would these methods be the same or different if one were assessing close friendships at ages 6, 11, and 17? 3. List at least five ways in which interactions among friends and among nonfriends in elementary school likely differ (e.g., type of activities, style of interaction). In what ways might such differences, if they exist, influence children’s socioemo- tional development? 4. Consider a child who is growing up in an isolated area with few peers nearby and is being schooled at home. In what ways might his or her daily experience differ from that of children attending school? How might this affect his or her development, positively or negatively? What factors might mitigate or increase these effects? n Popular children—those who rank high on sociometric measures—tend to be socially skilled, prosocial, and well regu- lated in their expression of emotion and behavior. In contrast, children who are perceived as popular in terms of high status often are aggressive and not always well liked. n Children who are rejected by their peers often (but not always) are aggressive and/or socially withdrawn. Rejected- aggressive children are low in social skills, tend to make hostile attributions about others’ intentions, and have trouble coming up with constructive strategies for dealing with difficult social situations. Withdrawn children who are rejected during preschool tend to be aggressive and hostile. n Children who are withdrawn from their peers but are not hos- tile or aggressive are at less risk for rejection during the early school years, although they tend to become rejected later in elementary school. n Neglected children—those who are not nominated by peers as either liked or disliked—tend to be less sociable, aggressive, and disruptive than average children. They display relatively few behaviors that differ greatly from those of many other children. n Controversial children tend to have characteristics of both popular and rejected children: they tend to be aggressive, dis- ruptive, and prone to anger, as well as helpful, cooperative, sociable, good at sports, and humorous. n Although children’s status with their peers frequently changes over time, those children who are rejected frequently remain rejected. Children who are neglected or controversial are particularly likely to change their status, even over short periods. n In general, in numerous cultures, children who are popular or rejected share similar characteristics. However, reticent behavior may be more valued in some East Asian cultures and has, at least until recently, been related in China to others’ per- ceptions of a child’s social competence. n Rejection by peers in childhood—especially rejection because of aggression—predicts subsequent academic problems, delinquency, substance abuse, social withdrawal, and lone- liness and depression. Children who are consistently with- drawn, reticent, and wary with familiar people, including peers, are more likely than less withdrawn children to expe- rience internalizing problems such as depression, low self- worth, and loneliness concurrently and at older ages. It is likely that children’s maladaptive behavior and their peer status both play a causal role in their future adjustment— separately and in combination. The Role of Parents in Children’s Peer Relationships n Consistent with the predictions of attachment theorists, securely attached children tend to be more positive in their behavior and affect, more socially skilled, and better liked than insecurely attached children. n Parents of socially competent and popular children are more likely than parents of less competent children to use warm control, positive verbalizations, reasoning, and explanations in interactions with their children. They also hold more posi- tive beliefs about their children’s abilities. It is likely that the causal links between quality of parenting and children’s social competence are bidirectional and that both environmental and biological factors play a role in the development of children’s social competence with peers. n Parents are the gatekeepers of young children’s peer interac- tions in the sense that they organize and control their chil- dren’s social experiences. n Some parents provide emotional coaching for their children to help them in their social interactions with peers. Such coaching, if appropriate and sensitive, often is associated with children’s social competence. n Stressors such as poverty and marital conflict appear to have a negative effect on the quality of parenting, which in turn is linked to low peer competence in children. C H A P T E R S U M M A R Y n 551 Key Terms aggressive-rejected children, p. 535 cliques, p. 526 controversial (peer status), p. 537 crowds, p. 529 friendship, p. 513 gang, p. 528 neglected (peer status), p. 537 peers, p. 512 popular (peer status), p. 534 reciprocated best friendship, p. 520 rejected (peer status), p. 535 relational aggression, p. 535 social skills training, p. 539 sociometric status, p. 533 victimized (peer status), p. 542 withdrawn-rejected children, p. 536 552 F IN E A R T P H O T O G R A P H IC L IB R A R Y, L O N D O N / A R T R E S O U R C E , N Y V I C TO R G I L B E RT, Make Believe 553 chapter 14: Moral Development n Moral Judgment Piaget’s Theory of Moral Judgment Kohlberg’s Theory of Moral Judgment Prosocial Moral Judgment Domains of Social Judgment Review n The Early Development of Conscience Factors Affecting the Development of Conscience Review n Prosocial Behavior The Development of Prosocial Behavior The Origins of Individual Differences in Prosocial Behavior Box 14.1: A Closer Look Cultural Contributions to Children’s Prosocial and Antisocial Tendencies Box 14.2: Applications School-Based Interventions for Promoting Prosocial Behavior Review n Antisocial Behavior The Development of Aggression and Other Antisocial Behaviors Consistency of Aggressive and Antisocial Behavior Box 14.3: A Closer Look Oppositional Defiant Disorder and Conduct Disorder Characteristics of Aggressive-Antisocial Children and Adolescents The Origins of Aggression Box 14.4: Applications The Fast Track Intervention Biology and Socialization: Their Joint Influence on Children’s Antisocial Behavior Review n Chapter Summary 554 I n April 1999, Eric Harris and Dylan Klebold, two students at Columbine High School in Littleton, Colorado, killed a dozen students and a teacher and injured 23 other persons. As terrible as this incident was, it could have been much worse. The two adolescents, who had planned the massacre carefully for months, had actually prepared 95 explosive devices that did not go off because of an electronic failure. One set of explosives was supposed to go off in the caf- eteria, killing many students and forcing others to flee into the schoolyard, where Harris and Klebold had planned to hide in wait and gun them down. Another set of explosives in the killers’ cars in the school parking lot was timed to explode after the police and paramedics arrived on the scene, causing more death and chaos. In videotapes made weeks before the attacks, the boys gleefully predicted that they would kill 250 people and bragged about the publicity they would get for their actions. They also made it clear that their attack was payback for having been humiliated and rejected by their peers: on one videotape, Harris, holding a sawed- off shotgun, declared, “Isn’t it fun finally to get the respect that we are going to deserve?” (quoted in Aronson, 2000, p. 86). One might think that Harris and Klebold had suffered terrible childhoods. Yet, from all reports, their parents were probably more supportive than the average par- ents. And although the pair did endure considerable peer rejection at Columbine, Harris, at least, was a fairly popular student at his school in Plattsburgh, New York, before he moved to Littleton. Explanations for why Harris and Klebold did what they did are not as simple as they might initially seem. In striking contrast to the lethally self-centered actions of Harris and Klebold, in the midst of the carnage, some students stayed with and tried to assist a teacher and other students who were shot. One boy running for his life helped a badly wounded girl get to an exit. Another boy draped himself over his sister and her friend to protect them from being shot (Gibbs, 1999). These students were concerned with others’ lives even when their own were at risk. The Columbine tragedy and more recent incidents, like the 2012 Sandy Hook school slayings in Connecticut, are additions to a long list of incidents that raise questions about why some adolescents become involved in antisocial and illegal behavior, ranging from vandalism and other forms of delinquency to horrific violent crime. The starting point for finding answers to these questions is understanding the aspects of children’s think- ing and behavior that contribute to morality. To act in moral ways on a regular basis, children must have an understanding of right and wrong and the reasons why certain actions are moral or immoral. In addition, they must have a conscience, that is, they must be concerned about act- ing in a moral manner and feel guilty when they do not. When studying moral development, researchers have focused on a number of different questions related to these requirements. How do children think about moral issues and how does that thinking change with age? Does children’s reasoning about moral issues relate to their behavior? How early do caring and sharing, or aggression and cruelty, first appear in children? What factors contribute to differences among children in the degree to which they display helpful and caring or antisocial behaviors? Can steps Themes n Nature and Nurture n The Active Child n Continuity/Discontinuity n Mechanisms of Change n The Sociocultural Context n Individual Differences n Research and Children’s Welfare Although many contributing factors to the Columbine tragedy have been identi- fied, the precise reasons for the actions of Harris and Klebold may never be known. As you will discover in this chapter, moral development—and whether an individual is inclined to prosocial or aggressive, antisocial behavior—depends on the interaction of a great many variables. G A R Y C A S K E Y / R E U T E R S N E W M E D IA I N C . / C O R B IS M O R A L J U D G M E N T n 555 be taken to help children develop caring and helpful behaviors and reduce the like- lihood of their developing immoral or antisocial behaviors? We start our discussion of moral development by examining children’s moral judgment—that is, how children think about situations involving moral decisions. Then we examine findings on the early emergence of conscience and the develop- ment of prosocial behaviors—behaviors such as helping and sharing that benefit others. Next, we turn to aggression and other antisocial behaviors such as stealing. As you will see, children’s moral development is influenced by advances in their social and cognitive capacities, as well as by genetic factors and environmental fac- tors, including family and cultural influences. Therefore, the themes of individual differences, nature and nurture, and the sociocultural context will be prominent in our discussions. In addition, theory and research on moral judgment grew out of Piaget’s work in this area, which, like his theory on cognitive development (see Chapter 4), involves stages of development and assumes that children actively try to understand the world around them. Consequently, the themes of continuity/ discontinuity, mechanisms of change, and the active child are evident in our consider- ation of the development of moral judgment. Also in play is the theme of research and children’s welfare, as we survey intervention programs that are designed to pro- mote prosocial thinking and behavior and prevent antisocial behavior. Moral Judgment The morality of a given action cannot be determined at face value. Consider a girl who steals food to feed her starving sister. Stealing is usually regarded as an immoral behavior, but obviously the morality of this girl’s behavior is not so clear. Or consider an adolescent male who offers to help fix a peer’s bike but does so because he wants to borrow it later, or perhaps wants to find out if the bike is worth stealing. Although this adolescent’s behavior may appear altruistic on the surface, it is morally ambiguous, at best, in the first instance and clearly immoral in the sec- ond. These examples illustrate that the morality of a behavior is based partly on the cognitions—including conscious intentions and goals—that underlie the behavior. Indeed, some psychologists (as well as philosophers and educators) believe that the reasoning behind a given behavior is critical for determining whether that behavior is moral or immoral, and they maintain that changes in moral reasoning form the basis of moral development. As a consequence, much of the research on children’s moral development has focused on how children think when they try to resolve moral conflicts and how their reasoning about moral issues changes with age. The most important contributors to the current understanding of the devel- opment of children’s moral reasoning are Piaget and Lawrence Kohlberg, both of whom took a cognitive developmental approach to studying the development of morality. Piaget’s Theory of Moral Judgment The foundation of cognitive theories about the origin of morality is Piaget’s book The Moral Judgment of the Child (1932/1965). In it, Piaget describes how chil- dren’s moral reasoning changes from a rigid acceptance of the dictates and rules of authorities to an appreciation that moral rules are a product of social interaction and are therefore modifiable. Piaget believed that interactions with peers, more than adult influence, account for advances in children’s moral reasoning. 556 n CHApter 14 MORAL DEvELOPMENT After children heard these stories, they were asked which boy was naughtier, and why. Children younger than 6 years typically said that the child who broke 15 cups was naughtier. In contrast, older children said that the child who was try- ing to sneak jam was naughtier, even though he broke only one cup. Partly on the basis of children’s responses to such vignettes, Piaget concluded that there are two stages of development in children’s moral reasoning, as well as a transitional period between the stages. The Stage of the Morality of Constraint The first stage of moral reasoning, referred to as the morality of constraint, is most characteristic of children who have not achieved Piaget’s stage of concrete operations—that is, children younger than 7 years (see Chapter 4). Children in this stage regard rules and duties to others as unchangeable “givens.” In their view, justice is whatever authorities (adults, rules, or laws) say is right, and authorities’ punish- ments for noncompliance are always justified. Acts that are not consistent with rules and authorities’ dictates are “bad”; acts that are consistent with them are “good.” It is in this stage that children believe that what determines whether an action is good or bad are the consequences of the action, not the motives or intentions behind it. Piaget suggested that young children’s belief that rules are unchangeable is due to two factors, one social and one cognitive. First, Piaget argued that parental control of children is coercive and unilateral, leading to children’s unquestioning respect for rules set by adults. Second, children’s cognitive immaturity causes them to believe that rules are “real” things, like chairs or gravity, that exist outside people and are not the product of the human mind. The Transitional Period According to Piaget, the period from about age 7 or 8 to age 10 represents a tran- sition from the morality of constraint to the next stage. During this transitional period, children typically have more interactions with peers than previously, and these interactions are more egalitarian, with more give-and-take, than are their interactions with adults. In games with peers, children learn that rules can be piaget (1932/1965) argued that through games children learn that rules are a cre- ation of human beings—that they are not absolute but are interpreted, and they can be changed, by the consensus of the peer group. S T O C K C O N N E C T IO N / S U P E R S T O C K Piaget initially studied children’s moral reasoning by observing children playing games, such as marbles, in which they often deal with issues related to rules and fairness. In addition, Piaget interviewed children to examine their thinking about issues such as transgressions of rules, the role of intentionality in morality, fairness of punishment, and justness when distributing goods among people. In these open- ended interviews, he typically presented children with pairs of short vignettes such as the following: A little boy who is called John is in his room. He is called to dinner. He goes into the dining room. But behind the door there was a chair, and on the chair there was a tray with fifteen cups on it. John couldn’t have known that there was all this behind the door. He goes in, the door knocks against the tray, bang go the fifteen cups, and they all get broken! Once there was a little boy whose name was Henry. One day when his mother was out he tried to get some jam out of the cupboard. He climbed up on to a chair and stretched out his arm. But the jam was too high up and he couldn’t reach it and have any. But while he was trying to get it he knocked over a cup. The cup fell down and broke. (Piaget, 1932/1965, p. 122) M O R A L J U D G M E N T n 557 constructed and changed by the group. They also increasingly learn to take one an- other’s perspective and to cooperate. As a consequence, children start to value fair- ness and equality and begin to become more autonomous in their thinking about moral issues. Piaget viewed children as taking an active role in this transition, using information from their social interactions to figure out how moral decisions are made and how rules are constructed. The Stage of Autonomous Morality By about age 11 or 12, Piaget’s second stage of moral reasoning emerges. In this stage, referred to as the stage of autonomous morality (also called moral relativism), children no longer accept blind obedience to authority as the basis of moral de- cisions. They fully understand that rules are the product of social agreement and can be changed if the majority of a group agrees to do so. In addition, they con- sider fairness and equality among people as important factors to consider when constructing rules. Children at this stage believe that punishments should “fit the crime” and that punishment delivered by adults is not necessarily fair. They also consider individuals’ motives and intentions when evaluating their behavior; thus, they view breaking one cup while trying to sneak jam as worse than accidentally breaking 15 cups. According to Piaget, all normal children progress from the morality of constraint to autonomous moral reasoning. Individual differences in the rate of their progress are due to numerous factors, including differences in children’s cognitive maturity, in their opportunities for interactions with peers and for reciprocal role taking, and in how authoritarian and punitive their parents are. Evaluation of Piaget’s Theory Piaget’s general vision of moral development has received some support from empirical research. Studies of children from many countries and various racial or ethnic groups have shown that with age, boys and girls increasingly take motives and intentions into account when judging the morality of actions (N. E. Berg & Mussen, 1975; Lickona, 1976). In addition, parental punitiveness, which would be expected to reinforce a morality of constraints, has been associated with less mature moral reasoning and moral behavior (M. L. Hoffman, 1983). Finally, consistent with Piaget’s belief that cognitive development plays a role in the development of moral judgment, children’s performance on tests of perspective-taking skills, Piag- etian logical tasks, and IQ tests have all been associated with their level of moral judgment (N. E. Berg & Mussen, 1975; Lickona, 1976). Some aspects of Piaget’s theory, however, have been soundly faulted. For exam- ple, there is little evidence that peer interaction per se stimulates moral development (Lickona, 1976). Rather, it seems likely that the quality of peer interactions— for example, whether or not they involve cooperative interactions—is more important than mere quantity of interaction with peers. Piaget also underestimated young children’s ability to appreciate the role of intentionality in morality (Nobes, Panagiotaki, & Pawson 2009). When Piagetian moral vignettes are presented in ways that make the individuals’ intentions more obvious—such as by using video- taped dramas—preschoolers and early elementary school children are more likely to recognize individuals with bad intentions (Chandler et al., 1973; Grueneich, 1982; Yuill & Perner, 1988). It is probable that in Piaget’s research, young children focused primarily on the consequences of the individuals’ actions because conse- quences (e.g., John’s breaking the 15 cups) were very salient in his stories. 558 n CHApter 14 MORAL DEvELOPMENT In addition, many 4- and 5-year-olds do not think that a person caused a nega- tive outcome “on purpose” if they have been explicitly told that the person had no foreknowledge of the consequences of his or her action or believed that the out- come of the action would be positive rather than negative (Pellizzoni, Siegal, & Surian, 2009). Moreover, even younger children seem to use knowledge of inten- tionality to evaluate others’ behavior. In one study, 3-year-olds who saw an adult intend (but fail) to hurt another adult were less likely to help that person than they were if the person’s behavior toward the other adult was neutral (intended to neither help nor hurt the other). In contrast, they helped an adult who accidently caused harm as much as they helped an adult whose behavior was neutral (Vaish, Carpenter, & Tomasello, 2010). Equally impressive, 21-month-olds in another study were more likely to help an adult who had tried (but failed) to assist them in retrieving a toy than an adult who had been unwilling to assist them. They were also more likely to help an adult who had tried (but failed) to assist them than an adult whose intentions had not been clear (Dunfield & Kuhlmeier, 2010). Finally, as you will see later in the chapter, it is clear that young children do not believe that some actions, such as hurting others, are right even when adults say they are. Whatever its shortcomings, Piaget’s theory provided the basis for subsequent research on the development of moral judgment. The most notable example is the more complexly differentiated theory of moral development formulated by Kohlberg. Kohlberg’s Theory of Moral Judgment Heavily influenced by the ideas of Piaget, Kohlberg (1976; Colby & Kohlberg, 1987a) was primarily interested in the sequences through which children’s moral reasoning develops. On the basis of a 20-year longitudinal study in which he first assessed boys’ moral reasoning at ages 10, 13, and 16, Kohlberg proposed that moral development proceeds through a specific series of stages that are discontinu- ous and hierarchical. That is, each new stage reflects a qualitatively different, more adequate way of thinking than the one before it. Kohlberg assessed moral judgment by presenting children with hypotheti- cal moral dilemmas and then questioning them about the issues these dilemmas involved. The most famous of these dilemmas concerns a man named Heinz, whose wife was dying from a special kind of cancer: LE E L O C K W O O D / T IM E P IX There was one drug that the doctors thought might save her. It was a form of radium that a druggist in the same town had recently discovered. The drug was expensive to make, but the druggist was charging 10 times what it cost him to make. The sick woman’s husband, Heinz, went to everyone he knew to borrow the money and tried every legal means, but he could only get together about $2,000, which is half of what it cost. He told the druggist his wife was dying, and asked him to sell it cheaper or let him pay later. But the druggist said, “No, I discovered the drug and I’m going to make money from it.” So having tried every legal means, Heinz gets desperate and considers breaking into the man’s store to steal the drug for his wife. (Colby & Kohlberg 1987b, p. 1) After relating this dilemma to children, Kohlberg asked them ques- tions such as: Should Heinz steal the drug? Would it be wrong or right if he did? Why? Is it a husband’s duty to steal the drug for his wife if he can get it no other way? For Kohlberg, the reasoning behind choices of what to do in the dilemma, rather than the choices themselves, is what reflects the quality of their moral reasoning. For example, the response Kohlberg (pictured here), like piaget, argued that stages of moral reasoning involve a qualitative change in reasoning and that each stage represents a new way of thinking that replaces the child’s thinking at prior, lower levels. M O R A L J U D G M E N T n 559 that “Heinz should steal the drug because he probably won’t get caught and put in jail” was considered less advanced than “Heinz should steal the drug because he wants his wife to feel better and to live.” Kohlberg’s Stages On the basis of the reasoning underlying children’s responses, Kohlberg proposed three levels of moral judgment—preconventional, conventional, and postconven- tional (or principled). Preconventional moral reasoning is self-centered: it focuses on getting rewards and avoiding punishment. Conventional moral reasoning is centered on social relationships: it focuses on compliance with social duties and laws. Post- conventional moral reasoning is centered on ideals: it focuses on moral principles. Each of these three levels involves two stages of moral judgment (see Table 14.1). However, so few people ever attained the highest stage (Stage 6—Universal Ethical Principles) of the postconventional level that Kohlberg (1978) eventually stopped TABLE 14.1 Kohlberg’s Levels and Stages of Moral reasoning Preconventional Level Stage 1: Punishment and Obedience Orientation. At Stage 1, what is seen as right is obedience to authorities. Children’s “conscience” (what makes them decide what is right or wrong) is fear of punishment, and their moral action is motivated by avoidance of punishment. The child does not consider the interests of others or recognize that they differ from his or her own interests. Examples of reasoning for (pro) and against (con) Heinz’s stealing the drug for his wife are as follows: Pro: If you let your wife die, you will get in trouble. You’ll be blamed for not spending the money to save her and there’ll be an investigation of you and the druggist for your wife’s death. Con: You shouldn’t steal the drug because you’ll be caught and sent to jail if you do. If you do get away, your conscience would bother you thinking how the police would catch up with you at any minute (Kohlberg, 1969, p. 381). Stage 2: Instrumental and Exchange Orientation. At Stage 2, what is right is what is in one’s own best interest or involves equal exchange between people (tit-for-tat exchange of benefits). Pro: If you do happen to get caught, you could give the drug back and you wouldn’t get much of a sentence. It wouldn’t bother you much to serve a little jail term, if you have your wife when you get out. Con: He may not get much of a jail term if he steals the drug, but his wife will probably die before he gets out so it won’t do him much good. If his wife dies, he shouldn’t blame himself, it wasn’t his fault she has cancer (Kohlberg, 1969, p. 381). Conventional Level Stage 3: Mutual Interpersonal Expectations, Relationships, and Interpersonal Conformity (“Good Girl, Nice Boy”) Orientation. In Stage 3, good behavior is doing what is expected by people who are close to the person or what people generally expect of someone in a given role (e.g., “a son”). Being “good” is important in itself and means having good motives, showing concern about others, and maintaining good relationships with others. Pro: No one will think you’re bad if you steal the drug, but your family will think you’re an inhuman husband if you don’t. If you let your wife die, you’ll never be able to look anybody in the face again. Con: It isn’t just the druggist who will think you’re a criminal, everyone else will, too. After you steal it, you’ll feel bad thinking how you’ve brought dishonor on your family and yourself; you won’t be able to face anyone again (Kohlberg, 1969, p. 381). Stage 4: Social System and Conscience (“Law and Order”) Orientation. Right behavior in Stage 4 involves fulfilling one’s duties, upholding laws, and contributing to society or one’s group. The individual is motivated to keep the social system going and to avoid a breakdown in its functioning. Pro: In most marriages, you accept the responsibility to look after one another’s health and after their life and you have the responsibility when you live with someone to try and make it a happy life (Colby & Kohlberg, 1987b, p. 43). In the revised coding manual, Colby and Kohlberg (1987b) provide virtually no examples of Stage 4 reasoning supporting the decision that Heinz should not steal the drug for his wife. However, they provide reasons for not stealing the drug for a pet: Heinz should not steal for a pet because animals cannot contribute to society (p. 37). Postconventional or Principled Level Stage 5: Social Contract or Individual Rights Orientation. At Stage 5, right behavior involves upholding rules that are in the best interest of the group (“the greatest good for the greatest number”), are impartial, or were agreed upon by the group. However, some values and rights, such as life and liberty, are universally right and must be upheld in any society, regardless of majority opinion. It is difficult to construct a Stage 5 reason that justifies not stealing the drug. Pro: Heinz should steal the drug because the right to life supersedes or transcends the right to property (Colby & Kohlberg, 1987b, p. 11). Pro: Heinz is working from a hierarchy of values, in which life (at least the life of his wife) is higher than honesty. . . . Human life and its preservation—at least as presented here—must take precedence over other values, like Heinz’s desire to be honest and law abiding, or the druggist’s love of money and his rights. All values stem from the ultimate value of life (Colby & Kohlberg, 1987b, p. 54). Stage 6: Universal Ethical Principles. Right behavior in Stage 6 is commitment to self-chosen ethical principles that reflect universal principles of justice (e.g., equality of human rights, respect for the dignity of each human being). When laws violate these principles, the individual should act in accordance with these universal principles rather than with the law. 560 n CHApter 14 MORAL DEvELOPMENT scoring it as a separate stage, and many theorists consider it an elaboration of Stage 5 (Lapsley, 2006). Kohlberg argued that people in all parts of the world move through his stages in the same order, although they differ in how many stages they attain. As in Piaget’s the- ory, age- related advances in cognitive skills, especially perspective taking, are believed to underlie the develop- ment of higher-level moral judgment. Consistent with Kohlberg’s theory, people who have higher-level cognitive and perspective-taking skills and who are better educated exhibit higher-level moral judgment (Colby et al., 1983; Mason & Gibbs, 1993; Rest, 1983). In their initial longitudinal study, Kohlberg and his col- leagues (Colby et al., 1983) followed 58 boys into adulthood and found that moral judgment changed systematically with age (see Figure 14.1). When the boys were 10 years old, they used primarily Stage 1 reasoning (blind obe- dience to authority) and Stage 2 reasoning (self-interest). Thereafter, reasoning in these stages dropped off markedly. For most adolescents aged 14 and older, Stage 3 reasoning (being “good” to earn approval or maintain relationships) was the primary mode of reasoning, although some adolescents occasionally used Stage 4 reasoning (fulfilling duties and upholding laws to maintain social order). Only a small number of participants, even by age 36, ever achieved Stage 5 (upholding the best interests of the group while recognizing life and liberty as universal values). Critique of Kohlberg’s Theory Kohlberg’s work is important because it demonstrated that children’s moral judg- ment changes in relatively systematic ways with age. In addition, because individu- als’ levels of moral judgment have been related to their moral behavior, especially for people reasoning at higher levels (e.g., Kutnick, 1985; B. Underwood & Moore, 1982), Kohlberg’s work has been useful in understanding how cognitive processes contribute to moral behavior. Kohlberg’s theory and findings have also produced controversy and criticism. One criticism is that Kohlberg did not sufficiently differentiate between truly moral issues and issues of social convention (Nucci & Gingo, 2011) (we examine this Children’s and adolescents’ moral reasoning can be quite low-level. Moreover, even if their reasoning is at the conventional level, they sometimes act in ways that do not reflect their highest level of moral reasoning. B IL L A R O N / P H O T O E D IT 70 60 50 40 30 20 10 0 P er ce n ta ge o f re as on in g Stage 1 Stage 4 Stage 3 Stage 5 Stage 2 10 12 14 16 18 20 22 24 26 28 30 32 34 36 10 12–14 16–18 20–22 24–26 28–30 32–34 36 Age in years FIGURE 14.1 Mean percentage of moral reasoning at each stage for each age group this graph shows age trends in moral reasoning in Kohlberg’s longitudinal sample. (Adapted from Colby et al., 1983) M O R A L J U D G M E N T n 561 differentiation on pages 563–565). Another criticism pertains to cultural differences. Although children in many non-Western, nonindustrialized cultures start out rea- soning much the way Western children do in Kohlberg’s scoring system, their moral judgment within this system generally does not advance as far as that of their West- ern peers (e.g., Nisan & Kohlberg, 1982; Snarey, 1985). This finding has led to the objection that Kohlberg’s stories and scoring system reflect an intellectualized con- ception of morality that is biased by Western values (E. L. Simpson, 1974). In many non-Western societies, in which the goal of preserving group harmony is of critical importance and most conflicts of interest are worked out through face-to-face con- tact, issues of individual rights and civil liberties may not be viewed as especially rel- evant. Moreover, in some societies, obedience to authorities, elders, and religious dictates are valued more than principles of freedom and individual rights. Another criticism has to do with Kohlberg’s argument that change in moral development is discontinuous. Kohlberg asserted that because each stage is more advanced than the previous one, once an individual attains a new stage, he or she seldom reasons at a lower stage. However, research has shown that children and adults alike often reason at different levels on different occasions—or even on the same occasion (Rest, 1979). As a consequence, it is not clear that the development of moral reasoning is qualitatively discontinuous. Rather, children and adolescents may gradually acquire the cognitive skills to use increasingly higher stages of moral reasoning but also may use lower stages when it is consistent with their goals, motives, or beliefs in a particular situation. For example, even an adolescent who is capable of using Stage 4 reasoning may well use Stage 2 reasoning to justify a deci- sion to break the law for personal gain. A hotly debated issue regarding Kohlberg’s theory is whether there are gender differences in moral judgment. As noted previously, Kohlberg developed his con- ception of moral-reasoning stages on the basis of interviews with a sample of boys. Carol Gilligan (1982) argued that Kohlberg’s classification of moral judgment is biased against females because it does not adequately recognize differences in the way males and females reason morally. Gilligan suggested that because of the way they are socialized, males tend to value principles of justice and rights, whereas fe- males value caring, responsibility for others, and avoidance of exploiting or hurting others (Gilligan & Attanucci, 1988). This difference in moral orientation, according to Gilligan, causes males to score higher on Kohlberg’s dilemmas than females do. Contrary to Gilligan’s theory, there is little evidence that boys and girls, or men and women, score differently on Kohlberg’s stages of moral judgment (Turiel, 1998; L. J. Walker, 1984, 1991). However, consistent with Gilligan’s arguments, during adolescence and adulthood, females focus somewhat more on issues of caring about other people in their moral judgment (Garmon et al., 1996; Jaffee & Hyde, 2000). Differences in males’ and females’ moral reasoning seem to be most evident when individuals report on moral dilemmas in their own lives ( Jaffee & Hyde, 2000). Thus, Gilligan’s work has been very important in broadening the focus of research on moral reasoning and in demonstrating that males and females differ somewhat in the issues they focus on when confronting moral issues. Although Kohlberg’s stages probably are not as invariant in sequence nor as uni- versal as he claimed, they do describe changes in children’s moral reasoning that are observed in many Western societies. These changes are important because people with higher-level moral reasoning are more likely to behave in a moral manner (Kohlberg & Candee, 1984; Matsuba & Walker, 2004) and to assist others (Blasi, 1980), and they are less likely to engage in delinquent activities (Stams et al., 2006). Thus, understanding developmental changes in moral judgment provides insight into why, as children grow older, they tend to engage in more prosocial behavior. 562 n CHApter 14 MORAL DEvELOPMENT Prosocial Moral Judgment When children respond to Kohlberg’s dilemmas, they are choosing between two acts that are wrong—for example, stealing or allowing someone to die. However, there are other types of moral dilemmas children encounter in which the choice is between personal advantage versus fairness to, or the welfare of, others (Damon, 1977; N. Eisenberg, 1986; Skoe, 1998). To determine how children resolve these dilemmas, researchers present chil- dren with stories in which the characters must choose between helping someone or meeting their own needs. These dilemmas are called prosocial moral dilemmas and concern prosocial behavior—that is, voluntary behavior intended to benefit another, such as helping, sharing, and comforting of others. The following story illustrates the type of dilemma used with children 4 years or older (with slight modifications for the latter group): One day a boy named Eric was going to a friend’s birthday party. On his way he saw a boy who had fallen down and hurt his leg [see Figure 14.2]. The boy asked Eric to go to his house and get his parents so the parents could come and take him to a doctor. But if Eric did run and get the child’s parents, he would be late to the birthday party and miss the ice cream, cake, and all the games. What should Eric do? Why? (Eisenberg-Berg & Hand, 1979, p. 358) On these tests, children and adolescents use five levels of prosocial moral rea- soning, delineated by Eisenberg (1986), that resemble Kohlberg’s stages (see Table 14.2). Preschool children express primarily hedonistic reasoning (Level 1) in which their own needs are central. They typically indicate that Eric should go to the party because he wants to. However, preschoolers also often mention other people’s physical needs, which suggests that some preschoolers are concerned about other people’s welfare (Level 2). (For example, they may indicate that Eric should help because the other boy is bleeding or hurt.) Such recognition of others’ needs increases in the elementary school years. In addition, in elementary school, children increasingly express concern about social approval and acting in a manner that is considered “good” by other people and society (e.g., they indicate that Eric should help “to be good”; Level 3). In late childhood and adolescence, children’s judgments begin to be based, in varying degrees, on explicit perspective taking (Level 4a—e.g., “Eric should think about how he would feel in that situation”) and morally relevant affect such as sympathy, guilt, and positive feelings due to the real or imagined consequences of performing beneficial actions (e.g., “Eric would feel bad if he didn’t help and the boy was in pain”). The judgments of a minority of older adolescents reflect inter- nalized values and affect (Levels 4b and 5) related to not living up to those values (e.g., self-censure). In general, this pattern of changes in prosocial moral reasoning has been found for children in Brazil, Germany, Israel, and Japan (Carlo et al., 1996; N. Eisenberg et al., 1985; I. Fuchs et al., 1986; Munekata & Ninomiya, 1985). Nev- ertheless, children from different cultures do vary somewhat in their prosocial moral reasoning. For example, stereotypic and internalized reasoning were not clearly different factors for Brazilian older adolescents and adults, whereas the two types of reasoning were somewhat more different for similar groups in the United States (Carlo et al., 2008). Moreover, older children (and adults) in some traditional societies in Papua New Guinea exhibit higher-level reasoning less often than do people of the same age in Western cultures. However, the types of FIGURE 14.2 this is one of the pic- tures that accompany the prosocial moral- reasoning vignette of eric’s birthday-party dilemma. N A N C Y E IS E N B E R G prosocial behavior n voluntary behavior intended to benefit another, such as helping, sharing, and comforting of others M O R A L J U D G M E N T n 563 reasoning they frequently use—reasoning that pertains to others’ needs and the relationship between people—are consistent with the values of a culture in which people must cooperate with one another in face-to-face interactions in order to survive (Tietjen, 1986). In nearly all cultures, reasoning that reflects the needs of others and global concepts of good and bad behavior (Kohlberg’s Stage 3 and Eisenberg’s Level 3) emerges at somewhat younger ages on prosocial dilemmas than on Kohlberg’s moral dilemmas. With age, children’s prosocial moral judgment, like their reasoning on Kohlberg’s moral dilemmas, becomes more abstract and based more on internalized principles and values (N. Eisenberg, 1986; N. Eisenberg et al., 1995). Paralleling the case with moral reasoning on Kohlberg’s measure, in numerous cultures those children, ado- lescents, and young adults who use higher-level prosocial moral reasoning tend to be more sympathetic and prosocial in their behavior than do peers who use lower- level prosocial moral judgment (Carlo, Knight et al., 2010; N. Eisenberg, 1986; Janssens & Dekovic, 1997; Kumru et al., 2012). Domains of Social Judgment In everyday life, children make decisions about many kinds of actions, including whether to follow rules and laws or break them, whether to fight or walk away from conflict, whether to dress formally or informally, whether to study or goof off after school, and so on. Some of these decisions involve moral judgments; others involve TABLE 14.2 Levels of prosocial Behavior Level 1: Hedonistic, self-focused orientation. The individual is concerned with his or her own interests rather than with moral considerations. Reasons for assisting or not assisting another include the prospects of direct personal gain or future reciprocation and whether one needs or likes the other person. (Predominant mode primarily for preschoolers and younger elementary school children.) Level 2: Needs-based orientation. The individual expresses concern for the physical, material, and psychological needs of others even when those needs conflict with his or her own. This concern is expressed in the simplest terms, without clear evidence of self-reflective role taking, verbal expressions of sympathy, or reference to such emotions as pride or guilt. (Predominant mode for many preschoolers and many elementary school children.) Level 3: Approval and/or stereotyped orientation. The individual justifies engaging or not engaging in prosocial behavior on the basis of others’ approval or acceptance and/or on stereotyped images of good and bad persons and behavior. (Predominant mode for some elementary school and high school students.) Level 4a: Self-reflective empathic orientation. The individual’s judgments include evidence of self- reflective sympathetic responding or role taking, concern with the other’s humanness, and/or guilt or positive emotion related to the consequences of one’s actions. (Predominant mode for a few older elementary school children and many high school students.) Level 4b: Transitional level. The individual’s justifications for helping or not helping involve internalized values, norms, duties, or responsibilities. They may also reflect concerns for the condition of the larger society or refer to the necessity of protecting the rights and dignities of other persons. These ideals, however, are not clearly or strongly stated. (Predominant mode for a minority of people of high school age or older.) Level 5: Strongly internalized stage. The individual’s justifications for helping or not helping are based on internalized values, norms, or responsibilities; the desire to maintain individual and societal contractual obligations or improve the condition of society; and the belief in the rights, dignity, and equality of all individuals. This level is also characterized by positive or negative emotions related to whether or not one succeeds in living up to one’s own values and accepted norms. (Predominant mode for only a small minority of high school students.) Source: Adapted from N. Eisenberg, 1986 564 n CHApter 14 MORAL DEvELOPMENT social conventional judgments; and still others involve personal judgments (Nucci, 1981; Turiel, 2006). Moral judgments pertain to issues of right and wrong, fairness, and justice. Social conventional judgments pertain to customs or regulations intended to en- sure social coordination and social organization, such as choices about modes of dress, table manners, and forms of greeting (e.g., using “Sir” when addressing a male teacher). Personal judgments pertain to actions in which individual prefer- ences are the main consideration. For example, within Western culture, the choice of friends or recreational activities usually is considered a personal choice (Nucci & Weber, 1995). These distinctions are important because whether children perceive particular judgments as moral, social conventional, or personal affects the impor- tance they accord them. Children’s Use of Social Conventional Judgment In many cultures, children begin to differentiate between moral and social con- ventional issues at an early age ( J. G. Miller & Bersoff, 1992; Nucci, Camino, & Sapiro, 1996; Smetana et al., 2012; Tisak, 1995). By age 3, they generally believe that moral violations (e.g., stealing another child’s possession or hitting another child) are more wrong than social conventional violations (e.g., not saying “please” when asking for something or wearing other-gender clothing). By age 4, they believe that moral transgressions, but not social conventional transgressions, are wrong even if an adult does not know about them and even if adult authorities have not said they are wrong (Smetana & Braeges, 1990). This distinction is reflected in the following excerpt from an interview with a 5-year-old boy: Interviewer: This is a story about Park School. In Park School the children are allowed to hit and push others if they want. It’s okay to hit and push others. Do you think it is all right for Park School to say children can hit and push others if they want to? Boy: No. It is not okay. Interviewer: Why not? Boy: Because that is like making other people unhappy. You can hurt them that way. It hurts other people, hurting is not good. This boy is firm in his belief that hurting others is wrong, even if adults say it is acceptable. Children tend to justify their condemnation of moral violations by referring to violations of fairness and harm to others’ welfare (Turiel, 2008). Compare that reasoning with the boy’s response to a question about the accept- ability of a school policy that allows children to take off their clothes in hot weather. Interviewer: I know another school in a different city. . . . Grove School . . . At Grove School the children are allowed to take their clothes off if they want to. Is it okay or not okay for Grove School to say children can take their clothes off if they want to? Boy: Yes. Because this is the rule. Interviewer: Why can they have that rule? Boy: If that’s what the boss wants to do, he can do that. . . . He is in charge of the school. (Turiel, 1987, p. 101) With regard to both moral and social conventional issues in the family, children and, to a lesser degree, adolescents, believe that parents have authority (Smetana, moral judgments n decisions that per- tain to issues of right and wrong, fairness, and justice social conventional judgments n decisions that pertain to customs or regu- lations intended to secure social coordi- nation and social organization personal judgments n decisions that refer to actions in which individual prefer- ences are the main consideration M O R A L J U D G M E N T n 565 1988; Yau, Smetana, & Metzger, 2009), unless the parent gives commands that violate moral and conventional principles (Yamada, 2009). With respect to mat- ters of personal judgment, however, even preschoolers tend to believe that they themselves should have control, and older children and adolescents are quite firm in their belief that they should control choices in the personal domain (e.g., their appearance, how they spend their money, and their choice of friends) at home and at school (Lagattuta et al., 2010; Nucci & Gingo, 2011). At the same time, par- ents usually feel that they should have some authority over their children’s personal choices, even into adolescence, so parents and teenagers frequently do battle in this domain—battles that parents often lose (Lins-Dyer & Nucci, 2007; Smetana, 1988; Smetana & Asquith, 1994). Cultural and Socioeconomic Differences People in different cultures sometimes vary in whether they view decisions as moral, social conventional, or personal (Shweder et al., 1987). Take the ques- tion of one’s obligation to attend to the minor needs of parents and the moderate needs of friends or strangers. Hindu Indians believe that they have a clear moral obligation to attend to these needs ( J. G. Miller, Bersoff, & Harwood, 1990). In contrast, Americans appear to consider it a matter of personal choice or a com- bination of moral and personal choice. This difference in perceptions may be due to the strong cultural emphasis on individual rights in the United States and the emphasis on duties to others in India (Killen & Turiel, 1998; J. G. Miller & Bersoff, 1995). Cultural differences with regard to which events are considered moral, social conventional, or personal sometimes arise from religious beliefs (Turiel, 2006; Wainryb & Turiel, 1995). For example, Hindus in India believe that if a widow eats fish, she has committed an immoral act. In Hindu society, fish is viewed as a “hot” food, and eating “hot” food is believed to stimulate the sexual appe- tite. Consequently, traditional Hindu adults and children assume that a widow who eats fish will behave immorally and offend her husband’s spirit. Underly- ing this belief is the obligation that Hinduism places on a widow to seek salva- tion and be reunited with the soul of her husband rather than initiating another relationship (Shweder et al., 1987). Of course, for most other people in the world, a widow’s eating fish would be considered a matter of personal choice. Thus, beliefs regarding the significance and consequences of various actions in different cultures can influence the designation of behaviors as moral, social conventional, or personal. Even within a given culture, different religious beliefs may affect what is consid- ered a moral or a social-conventional issue. In Finland, for example, conservative religious adolescents are less likely to make a distinction between the moral and social-conventional domain than are nonreligious youths. For the religious youths, the most crucial deciding factor for nonmoral (conventional) issues is God’s word as written in the Bible (i.e., whether or not the Bible says a particular social con- vention is wrong; Vainio, 2011). Socioeconomic class can also influence the way children make such designations. Research in the United States and Brazil indicates that children of lower-income families are somewhat less likely than middle-class children to differentiate sharply between moral and social conventional actions and, prior to adolescence, are also less likely to view personal issues as a matter of choice. These differences may be due to the tendency of individuals of low socioeconomic status both to place a Children in India are much more likely than children in the United States to say that helping other people is a moral obligation, not a matter of personal choice. M A R K D O W N E Y / L U C ID I M A G E S 566 n CHApter 14 MORAL DEvELOPMENT greater emphasis on submission to authority and to allow children less autonomy (Nucci, 1997). This social-class difference in children’s views may evaporate as youths approach adolescence, although Brazilian mothers of lower-income youths still claim more control over personal issues than do mothers of middle-income youths (Lins-Dyer & Nucci, 2007). review: How children think about moral issues provides one basis for their moral or immoral behav- ior. Piaget delineated two moral stages—morality of constraint and autonomous morality— separated by a transitional stage. In the first stage, children regard rules as fixed and tend to weigh consequences more than intentions in evaluating actions. According to Piaget, a combination of cognitive growth and egalitarian, cooperative interactions with peers brings children to the autonomous stage, in which they recognize that rules can be changed by group consent and judge the morality of actions on the basis of intentions more than con- sequences. Aspects of Piaget’s theory have not held up well to criticism—for example, children use intentions to evaluate behavior at a younger age than Piaget believed they could—but his theory provided the foundation for Kohlberg’s work on stages of moral reasoning. Kohlberg outlined three levels of moral judgment—preconventional, conventional, and postconventional—each initially containing two stages (Stage 6 was subsequently dropped). He hypothesized that his sequence of stages reflected age-related discontinuous changes in moral reasoning and that children everywhere go through the same stage progression (although they may stop development at different points). Several aspects of Kohlberg’s theory are controversial, including whether children’s moral reasoning moves through dis- continuous stages of development; whether the theory is valid for all cultures; and whether there are gender differences in moral judgment. Research on other types of moral judgment, such as prosocial moral judgment, suggests that children’s concerns about the needs of oth- ers emerge at a younger age than Kohlberg’s work indicates. However, with age, prosocial moral reasoning, like Kohlberg’s justice-oriented moral reasoning, becomes more abstract and based on internalized principles. There are important differences among the moral, social conventional, and personal domains of behavior and judgment—differences that even children recognize. For example, young children believe that moral transgressions, but not social conventional or personal vio- lations, are wrong regardless of whether adults say they are unacceptable. There are some cultural differences in whether a given behavior is viewed as having moral implications, but it is likely that people in all cultures differentiate among moral, social conventional, and per- sonal domains of functioning. The Early Development of Conscience We all are familiar with the notion of a conscience—that voice inside us that pushes us to behave in moral ways and makes us feel guilty if we do not. Stated more formally, conscience is an internal regulatory mechanism that increases the individual’s ability to conform to standards of conduct accepted in his or her culture. Consistent with Freud’s theory (see Chapter 9), it is likely that the conscience of a young child reflects primarily internalized parental stan- dards (although probably the standards of both parents, not just of the same- gender parent, as Freud suggested). The conscience restrains antisocial behavior or destructive impulses and promotes a child’s compliance with adults’ rules and standards, even when no one is monitoring the child’s behavior (Kochanska, 2002). The conscience can also promote prosocial behavior by causing the child conscience n an internal regulatory mechanism that increases the individual’s ability to conform to standards of conduct accepted in his or her culture T H E E A R L Y D E v E L O P M E N T O F C O N S C I E N C E n 567 to feel guilty when engaging in uncaring behavior or failing to live up to internalized values about helping others (N. Eisenberg, 2000; M. L. Hoffman, 1982). Factors Affecting the Development of Conscience Contrary to Freud’s idea that the conscience emerges as an outcome of identification with the same-gender parent at about age 4 to 6, children actually develop a conscience slowly over time. By age 2, toddlers start to show an appreciation for moral standards and rules and begin to exhibit signs of guilt when they do something wrong (Kopp, 2001; R. A. Thompson & Newton, 2010; Zahn-Waxler & Robinson, 1995). These two components of conscience—the desire to comply with rules and feelings of guilt when failing to do so— are quite stable in their early development from 22 to 45 months of age (Aksan & Kochanska, 2005; Kochanska et al., 2002). Children’s growing understanding of others’ emotions and goals, and their in- creasing capacity for empathic concern, are likely contributors to the development of conscience (R. A. Thompson, 2012). As they mature, children are more likely to take on their parents’ moral val- ues, and to exhibit guilt for violating those values, if their parents use disciplin- ary practices that deemphasize parental power and include rational explanations that help children understand and learn the parents’ values (Kochanska & Aksan, 2006; Laible et al., 2008; Volling et al., 2009). Children’s adoption of their par- ents’ values is also facilitated by a secure, positive parent–child relationship, which inclines children to be open to, and eager to internalize, their parents’ communi- cation of their values (Bretherton et al., 1997; Kochanska et al., 2005; Kochanska et al., 2008). Children may develop a conscience in different ways according to their tem- perament. Toddlers who are prone to fear (e.g., who are fearful of unfamiliar people or situations) tend to exhibit more guilt at a young age than do less fearful children (Kochanska et al., 2002). Moreover, for those infants who are prone to fear, the development of conscience seems to be promoted by the mother’s use of gentle discipline that includes reasoning with the child and providing nonmaterial incentives for compliance (Kochanska & Aksan, 2006). When mothers use gentle discipline, fearful children do not become so apprehensive and anxious that they tune out their mother’s messages about desired behavior. Gentle discipline arouses fearful children just enough that they attend to and remember what their mother tells them (Kochanska, 1993). In contrast, gentle discipline seems to be unrelated to the development of conscience in fearless young children, perhaps because it is insufficient to arouse their attention (Kochanska, 1997a). What does seem to foster the development of conscience in fearless children is a parent–child relationship characterized by secure attachment and mutual cooperation (Kochanska, 1995; Kochanska & Aksan, 2006). Fearless children appear motivated more by the desire to please their mother than by a fear of her (Kochanska, 1997b). Unfortunately, research on this topic seldom has been conducted with fathers, so it is not known whether the findings for the effects of mothers’ discipline also generalize to fathers’ discipline. The effects of parenting on children’s conscience also vary with their genes, which, as discussed in Chapter 10, affect temperament. This can be seen in the Young children often have not yet internal- ized some of their parents’ prohibitions and values. the degree to which they do so appears to depend in part on the quality of the parenting they receive and, in part, on their temperament. B LE N D I M A G E S / A LA M Y 568 n CHApter 14 MORAL DEvELOPMENT dynamic between maternal responsiveness—the mother’s acceptance of, and sen- sitivity to, the child—and the child’s genotype for the serotonin transporter gene, SLC6A4. As discussed in Chapter 11 (pages 436 and 437), a particular allele vari- ant of SLC6A4 is believed to make children especially reactive to their rearing environment. For children with this allele variant, high maternal responsiveness is associated with high levels of conscience at 15 to 52 months of age. Conversely, for children with this same variant, low maternal responsiveness is associated with low conscience. For children with a different genotype for SLC6A4, their level of conscience is unrelated to their mother’s responsiveness (Kochanska et al., 2011). This pattern is an example of differential susceptibility, whereby some children are more reactive than others are to the quality of parenting they receive, be it high or low quality. The early development of conscience undoubtedly contributes to whether chil- dren come to accept the moral values of their parents and society. Indeed, in a lon- gitudinal assessment of children’s behavioral and affective expression of guilt (in which they were led to believe that they had broken a valuable object), the children’s levels of guilt at 22 and 45 months of age predicted their morality at 54 months of age (e.g., their violating rules about touching prohibited toys, cheating on tasks, and expressing selfish and antisocial themes when discussing vignettes with mor- ally relevant topics) (Kochanska et al., 2002). This, in turn, predicted whether they engaged in hurtful or problematic social behavior at 67 months (Kochanska et al., 2008). In a related study, children’s internalization of parental rules at 2 to 4 years of age predicted their self-perceptions as being moral at 67 months (Kochanska et al., 2010). Therefore, the nature of early parent–child disciplinary interactions sets the stage for children’s subsequent moral development. review: The conscience is believed to reflect internalized moral standards; it restrains the child from engaging in immoral behavior and involves feelings of guilt for misbehavior. Contrary to Freud’s beliefs, the conscience emerges slowly over time, beginning before age 2. Children are more likely to internalize parental standards if they have secure attachments with their parents and if their parents use rational explanations in their discipline rather than exces- sive parental power. Factors that promote the development of conscience differ somewhat for children depending on their temperament and genetic inheritance. Prosocial Behavior As noted earlier, moral behavior is as important for moral development as are moral thinking and moral emotions. The same is true for prosocial behavior; all children are capable of prosocial behaviors, but children differ in how often they engage in these behaviors and in their reasons for doing so. Consider the behavior of the fol- lowing three preschool children: Sara is drawing a picture and has a box of crayons. Erin is sitting across from her, and wants to draw. But Erin has only a single crayon and all the rest are in use by other children. She looks around for crayons of other colors. After a short time, Erin looks somewhat distressed. Sara notices that Erin is looking for crayons and is distressed, so she smiles and hands Erin a few of her own crayons, saying, “Here, do you want to use these?” Marc is sitting at a table drawing with crayons when Manuel comes over and wants to draw. Manuel can’t find any crayons and shows signs of upset. Marc looks P R O S O C I A L B E H A v I O R n 569 at Manuel and then returns to his own drawing. Finally, Manuel asks Marc, “Can I have some crayons?” At first Marc ignores Manuel. After Manuel asks for crayons again, Marc hands Manuel three crayons without any comment or display of emotion. Sakina is drawing when Darren comes to the table, picks up a piece of paper, and looks around for crayons. When Darren can’t find any, he exhibits mild distress and then asks Sakina for some crayons. Sakina just ignores him. When Darren tries to take a crayon that Sakina is not using, Sakina angrily pushes him away. (Eisenberg, unpublished laboratory observations) Seeing that someone else is sad or in distress, Sara gladly shares without even being asked. Marc shares only if asked repeatedly. Sakina doesn’t share at all and does not seem to care if other children are upset. Do these dif- ferences in behavior forecast consistent differences in Sara’s, Marc’s, and Sakina’s positive moral behavior as they are grow- ing up? The answer is yes: there is some developmental consistency in children’s readiness to engage in prosocial behaviors, such as sharing, helping, and comforting (N. Eisenberg & Fabes, 1998; Knafo et al., 2008). In fact, children who, like Sara, share spontaneously with peers tend to be more concerned with oth- ers’ needs throughout childhood and adolescence and even in early adulthood. One longitudinal study found that, in com- parison with their peers, for example, they were more likely to assist other people even when doing so involved a cost to them- selves. As young adults, they reported that they felt responsible for the welfare of others and that they usually tried to suppress aggression toward others when angered. This view of them- selves was supported by friends, who rated them as more sympathetic than study participants who engaged in less spontaneous prosocial behavior in preschool (N. Eisenberg et al., 2002; N. Eisenberg, Guthrie et al., 1999). In contrast, children like Sakina are unlikely to be concerned with others’ needs and feelings when they are older. Of course, not all prosocial behaviors are of equal worth. Sometimes children help or share to get something in return, to gain social acceptance from peers, or to avoid their anger (“I’ll share my doll if you’ll be my friend”). However, most parents and teachers want children to perform prosocial behaviors not for rewards or social approval but for altruistic motives. Altruistic motives initially include empathy or sympathy for others and, at later ages, the desire to act in ways consistent with one’s own conscience and moral principles (N. Eisenberg, 1986). The Development of Prosocial Behavior The origins of altruistic prosocial behavior are rooted in the capacity to feel empathy and sympathy. As discussed in Chap- ter 10, empathy is an emotional reaction to another’s emotional state or condition (e.g., sadness, poverty) that is highly similar to (or consistent with) the other person’s state or condition (N. Eisenberg, 1986; M. L. Hoffman, 2000). For example, if a child becomes sad upon observing another person’s sadness or pain, the child is experiencing empathy. To experience empathy, chil- dren must be able to identify the emotions of others (at least to some degree) and understand that another person is feeling an emotion or is in some kind of need. In their second year, most children are willing to share objects and treats with their parents and with other children. H O W A R D S AY E R / A LA M Y altruistic motives n helping others for reasons that initially include empathy or sympathy for others and, at later ages, the desire to act in ways consistent with one’s own conscience and moral principles Children’s ability to sympathize with others appears to increase with age in early and middle childhood. these boys have just par- ticipated in a head-shaving event to show support for children with cancer and to help raise funds for cancer research. R IN G O C H IU / C O R B IS 570 n CHApter 14 MORAL DEvELOPMENT Sympathy is a feeling of concern for another in reaction to the other’s emotional state or condition. Although sympathy often is an outcome of empathizing with another’s negative emotion or negative situation, what distinguishes sympathy from empathy is the element of concern: people who experience sympathy for another person are not merely feel- ing the same emotion as the other person. An important factor contributing to empathy or sympathy is, obviously, the ability to take the perspective of others. Although early theorists such as Piaget believed that children are unable to do this until age 6 to 7 (Piaget & Inhelder, 1956/1977), it is now clear that chil- dren have some ability to understand others’ perspectives much earlier (Vaish, Carpenter, & Tomasello, 2009). By 10 to 14 months of age, and occasionally between age 8 and 12 months, children sometimes become disturbed and upset when they view other people who are upset (Knafo et al., 2008; Roth-Hanania et al., 2011). Of course, it may be that infants are not really sympathizing with others’ distress; they may become upset merely because they do not dif- ferentiate clearly between another person’s emotional distress and their own (M. L. Hoffman, 2000). Indeed, young children sometimes seek comfort from a parent when they see someone else upset or are upset both for another person and for themselves (Zahn-Waxler, Radke- Yarrow, & King, 1979). By 18 to 25 months of age, toddlers in laboratory studies sometimes share a personal object with an adult whom they have viewed being harmed by another (for example, by having a piece of personal property taken away or destroyed). They also will sometimes comfort an adult who appears to be injured or distressed, or help an adult retrieve a dropped object or obtain food (Dunfield et al., 2011; Vaish et al., 2009). Such behaviors are especially likely to occur if the adult explicitly and emotion- ally communicates his or her need (C. A. Brownell, Svetlova, & Nichols, 2009), but they sometimes occur even when the adult does not express an emotional reaction (Vaish et al., 2009). (It should be noted that in stud- ies like these, toddlers are particularly likely to help adults achieve a task or goal, like retrieving a dropped object [Warneken & Tomasello, 2006], but much less likely to share one of their own objects [Svetlova, Nichols, & Brownell, 2010].) In displaying empathy, children in the second year of life also are more likely to try to comfort someone who is upset than to become upset themselves, indicating that they know who it is that is suffering. Consider the following example: A neighbor’s baby boy cries. Jenny (18 months old) looked startled, her body stiff- ened. She approached and tried to give the baby cookies. She followed him around and began to whimper herself. She then tried to stroke his hair, but he pulled away. Later, Jenny approached her mother, led her to the baby, and tried to put mother’s hand on the baby’s head. He calmed down a little, but Jenny still looked worried. She continued to bring him toys and to pat his head and shoulders. (Radke-Yarrow & Zahn-Waxler, 1984, p. 89) In the second and third years of life, the frequency and variety of young children’s prosocial behaviors increase. Children not only increasingly comfort others (see Table 14.3) and share objects but also assist adults with various tasks such as sweeping, carrying objects, or setting the table (Rheingold, 1982; Warneken, Chen, & Toma- sello, 2006). Moreover, their prosocial behaviors at home often seem to be motivated by concern for others because they frequently show expressions of sympathy when E LI Z A B E T H C R E W S A N D Y C O X / G E T T Y I M A G E S Young children who view another child’s distress sometimes respond with looks of concern or attempts to console or help the distressed peer—about 20% of the time in a study of 16- to 33-month-olds (C. Howes & Farver, 1987). even young infants some- times show interest in a peer’s distress. P R O S O C I A L B E H A v I O R n 571 they help or comfort others (Knafo et al., 2008; Radke-Yarrow & Zahn-Waxler, 1984). As shown in Table 14.3, 25% of 23- to 25-month-olds showed concern when they observed someone in distress that they had not caused themselves. As should be clear from the table, however, young children do not regularly act in prosocial ways (S. Lamb & Zakhireh, 1997). Between the ages of 2 and 3, children most often ignore their siblings’ distress or need, or they simply watch without intervening. Occasionally, they even make the situation worse with teasing or aggression (Dunn, 1988; see “Aggressive behavior” in Table 14.3). In one study of children in a playgroup setting, for instance, 16- to 33-month-olds responded to peers’ distress only 22% of the time, usually by attempting to intervene on the peer’s behalf, comforting the peer, or bringing the peer’s distress to the attention of the caregiver (C. Howes & Farver, 1987). Consistent with our discussion in Chapter 13, these children were much more likely to help a friend than to help a child who was not a friend (N. Eisenberg, Fabes, & Spinrad, 2006; Fujisawa, Kutsukake, & Hasegawa, 2008). Children’s prosocial behaviors such as helping, sharing, and donating increase in frequency in the toddler years and from the preschool years through childhood (N. Eisenberg & Fabes, 1998; Knafo et al., 2008). However, proso- cial behavior seems to stabilize or even decline in early to mid-adolescence and rebounds somewhat in late adolescence and early adulthood (Carlo et al., 2007; N. Eisenberg et al., 2005; Luengo Kanacri et al., 2013; Nantel-Vivier et al., 2009). The Origins of Individual Differences in Prosocial Behavior Although children’s prosocial behaviors change with age, consistent with the theme of individual differences, there is great variation among children of the same age in their propensity to help, share with, and comfort others. Recall the behaviors of Sara, Marc, and Sakina, the three children described earlier in this section. Why do children of the same ages differ so much in their prosocial behavior? To identify the origins of these individual differences, we must consider the themes of nature and nurture and sociocultural context. Biological Factors Many biologists and psychologists have proposed that humans are biologically predisposed to be prosocial (Hastings, Zahn-Waxler, & McShane, 2005). They believe that humans have evolved the capacity for empathy and altruism because TABLE 14.3 Mothers’ reports of the proportion of times Children responded to Others’ Distress During the Second Year of Life When the child witnessed another’s distress When the child caused another’s distress 13–15 months 18–20 months 23–25 months 13–15 months 18–20 months 23–25 months Prosocial behavior .09 .21 .49 .07 .10 .52 Empathy or sympathy .09 .10 .25 .03 .03 .14 Aggressive behavior .01 .01 .03 .01 .04 .19 Self-distress (personal distress) .15 .12 .07 .34 .41 .33 Source: Adapted from Zahn-Waxler et al., 1992 Children display helping behaviors at home, often with chores, from an early age. JA C K Y C H A P M A N / A LA M Y 572 n CHApter 14 MORAL DEvELOPMENT these traits increase the likelihood of an individual’s genes being passed on to the next generation (M. L. Hoffman, 1981). According to this view, people who help others are more likely than less helpful people to be assisted when they them- selves are in need and, thus, are more likely to survive and reproduce (Trivers, 1983). In addition, assisting those with whom they share genes increases the like- lihood that those genes will be passed on to the next generation (E. O. Wilson, 1975). Evolutionary explanations for prosocial behavior, however, pertain to the human species as a whole and do not explain individual differences in empathy, sympathy, and prosocial behavior. Nonetheless, genetic factors do contribute to individual differences in these characteristics (e.g., Waldman et al., 2011). In twin studies with adults, twins’ re- ports of their own empathy and prosocial behavior are considerably more similar for identical twins than for fraternal twins (Gregory et al., 2009; Knafo & Israel, 2010). In one of the few twin studies of children’s prosocial behavior, researchers observed young twins’ reactions to adults’ simulations of distress in the home and in the laboratory. They also had the twins’ mothers report on their everyday prosocial behavior. On the basis of heritability estimates derived from this study, it appears that the role that genetic factors play in the children’s prosocial concern for others and in their prosocial behavior increases with age (Knafo et al., 2008). Recently, researchers have identified specific genes that might contribute to individual differences in prosocial tendencies (Knafo & Israel, 2010). For example, certain genes are associated with individual differences in oxytocin, a hormone that plays a role in a variety of social behaviors and emotion, including pair bonding and parenting, and has been associated with parental attachment, empathy, and pro- social behavior (N Eisenberg, Spinrad, & Knafo, under revision; R. Feldman, 2012; K. MacDonald & MacDonald, 2010; Striepens et al., 2011). How else might genetic factors affect empathy, sympathy, and proso- cial behavior? Most likely, their effects are related to differences in temper- ament. For instance, differences in children’s ability to regulate emotion are related to children’s empathy and sympathy. Children who tend to experi- ence emotion without getting overwhelmed by it are especially likely to ex- perience sympathy and to enact prosocial behavior (N. Eisenberg, Fabes, & Murphy, 1996; N. Eisenberg et al., 2007; Trommsdorff, Friedlmeier, & Mayer, 2007). Moreover, children who are not responsive to others’ emo- tions or are too inhibited to help others may be relatively unlikely to enact prosocial behaviors (Liew et al., 2011; S. K. Young, Fox, & Zahn-Waxler, 1999). Regulation is also related to children’s theory of mind (see page 267), and theory of mind predicts children’s prosocial behavior (Caputi et al., 2012). Thus, the effect of heredity on sympathy and prosocial behavior might be through individual differences in their social cognition. It seems, then, that genetic factors likely affect when and how children assist others through their effect on a number of dif- ferent aspects of children’s functioning. The Socialization of Prosocial Behavior A number of environmental factors also contribute to sympathy and pro- social behavior (Knafo & Plomin, 2006a, 2006b; Volbrecht et al., 2007). The primary environmental influence on children’s development of proso- cial behavior probably is their socialization in the family. Researchers have identified three ways in which parents socialize prosocial behavior in their Children are more likely to donate to charity if they see others donate and if adults explain to them how donating helps others. C H R IS A N D E R S O N / A U R O R A P R O S O C I A L B E H A v I O R n 573 children: (1) through their modeling and teaching prosocial behavior; (2) through their arranging opportunities for their children to engage in prosocial behavior; and (3) through their methods of disciplining their children and eliciting prosocial behavior from them. Parents also communicate and reinforce cultural beliefs about the value of prosocial behavior (see Box 14.1). BOX 14.1: a closer look CULTURAL CONTRIBUTIONS TO CHILDREN’S PROSOCIAL AND ANTISOCIAL TENDENCIES The amount of prosocial and antisocial be- havior that children display can be influ- enced by the particular culture they are part of (Graves & Graves, 1983; Turnbull, 1972). For example, children from traditional com- munities and subcultures (e.g., Mexicans and Mexican Americans) are more likely to cooperate on laboratory tasks than are chil- dren from urban, Westernized groups (N. Eisenberg & Mussen, 1989; Knight, Cota, & Bernal, 1993). Similar patterns have been found in observations of children interacting at home and in their neighbor- hoods (Whiting & Edwards, 1988; Whiting & Whiting, 1975): children in traditional socie- ties in Kenya, Mexico, and the Philippines helped, shared, and offered support to others in their families and communities more than did children in the United States, India, and Okinawa. In the more prosocial cultures, children often lived in extended families with many relatives. At a young age, they were as- signed chores that were very important for the welfare of other family members, such as caring for younger children and tending herds. As a result of taking on these duties, children may have learned that they were responsible for others and that their helping behavior was expected and valued by adults. However, there may be cultural differences in the people toward whom children’s caring behavior is directed. For example, in the re- search just discussed, Philippine children were more prosocial toward relatives than toward nonrelatives, whereas U.S. children were more prosocial toward nonrelatives than toward relatives (de Guzman, Carlo, & Ed- wards, 2008). Children in traditional cultures may be socialized to help people with whom they have close ties but may be relatively disinclined to help people with whom they don’t have a close connection. The multicultural study cited above also revealed cultural differences in children’s aggression (Whiting & Whiting, 1975). Chil- dren’s tendencies to assault, berate, and scold others were related primarily to fam- ily structure and interactions among par- ents. Children with lower rates of assaulting and reprimanding tended to live in cultures in which fathers were closely involved with their wives and children, helped their wives with the care of infants, and were relatively unlikely to assault their wives. In such fam- ily circumstances, children may have learned nonaggressive modes of social interaction from their fathers and were relatively unlikely to have been exposed to aggressive adult models. Even in various industrial societies today, there are differences in cultural values regarding prosocial and antisocial behavior. For instance, Mexican American youths are more prosocial if they espouse the traditional Mexican value of familism—a set of norms that promotes emotional and economic inter- dependence within an extended network of kin—rather than mainstream U.S. norms of individualism (Armenta et al., 2011). Along similar lines, the incidence of children’s sharing, helping, and comforting is higher in Taiwan and Japan than it is in the United States (Rao & Stewart, 1999; Stevenson, 1991). Again, in contrast to the U.S. valu- ing of self and competition, Chinese and Japanese cultures traditionally place great emphasis on teaching children to share and to be responsible for the needs of others in the group (the family, class, or commu- nity). In Japan, there also is an emphasis on creating a “community of learners” in the elementary school classroom—that is, teach- ing children to respond supportively to one another’s thoughts and feelings (M. Lewis, 1995). However, the traditional emphasis on prosocial behavior in many Asian cul- tures seems to be eroding (L. C. Lee & Zhan, 1991), perhaps due to increasing economic modernization and exposure to Western cul- ture and values. This may explain why Asian children have not been found to be more pro- social than Western children in several rela- tively recent studies outside the classroom (Kärtner, Keller, & Chaudhary, 2010; Trom- msdorff et al., 2007). Cross-cultural research has shown that girls who live in societies in which they are expected to take care of younger children are more prosocial than are girls who live in soci- eties that do not have this expectation. C AT H E R IN E U R S IL LO / S C IE N C E S O U R C E 574 n CHApter 14 MORAL DEvELOPMENT Modeling and the communication of values Just as they imitate many other behaviors, children tend to imitate other people’s helping and sharing behavior, including even that of unknown peers or adults (N. Eisenberg & Fabes, 1998). Children are especially likely to imitate the prosocial behavior of adults with whom they have a positive relationship (D. Hart & Fegley, 1995; Yarrow, Scott, & Zahn-Waxler, 1973). This may help explain the fact that parents and children tend to be similar in their levels of prosocial behavior and sympathy (Clary & Miller, 1986; N. Eisenberg et al., 1991; Stukas et al., 1999), although heredity may also contribute to the similarity between parent and child in sympathy and helpfulness. In a particularly interesting study, individuals who had risked their lives to rescue Jews from the Nazis in Eu- rope during World War II were interviewed many years later, along with “bystanders” from the same communities who had not been involved in rescue activities (Oliner & Oliner, 1988). As shown in Table 14.4, when recalling the values that they had learned from their parents and other influential adults, 44% of the rescuers mentioned gener- osity and caring for others, whereas only 21% of bystand- ers mentioned the same values. In addition, bystanders were almost twice as likely as rescuers to cite economic competence as a value learned from their parents. Bystanders also reported that their parents emphasized ethical obligations to family, community, church, and country, but not to other groups of people. In contrast, rescuers were seven times more likely than bystanders to report that their parents taught them that values related to caring should be applied to everyone (28% of rescuers; 4% of bystanders): “They taught me to respect all human beings.” “He taught me to love my neighbor—to consider him my equal whatever his nation- ality or religion.” (Oliner & Oliner, 1988, p. 165) Thus, the values parents convey to their children may influence not only whether children are prosocial but also toward whom they are prosocial. One effective way for parents to teach their children prosocial values and behaviors is to have discussions with them that appeal to their ability to sympa- thize. In laboratory studies, when elementary school children heard adults explic- itly point out the positive consequences of prosocial actions for others (e.g., “Poor children . . . would be so happy and excited if they could buy food and toys”), they were relatively likely to donate money anonymously to help other people (Eisen- berg-Berg & Geisheker, 1979; Perry, Bussey, & Freiberg, 1981). Children were less likely to donate anonymously if adults simply said that helping is “good” or “nice” and did not provide sympathy-arousing rationales for helping or sharing (Bryan & Walbek, 1970; N. Eisenberg & Fabes, 1998). Opportunities for prosocial activities Providing children with opportunities to engage in helpful activities can increase their willingness to take on prosocial tasks at a later time (N. Eisenberg et al., 1987; Staub, 1979). In the home, opportuni- ties to help others include household tasks that are performed on a routine basis and benefit others (Richman et al., 1988; Whiting & Whiting, 1975), although performance of household tasks may foster prosocial actions primarily toward family members (Grusec, Goodnow, & Cohen, 1996). For adolescents, voluntary TABLE 14.4 Values Learned from parents by rescuers and Bystanders (percent of rescuers and Bystanders Who reported Learning a Given type of Value from parents) Type of value Rescuers (%) Bystanders (%) Economic competence 19 34 Independence 6 8 Fairness/equity (including reciprocity) 44 48 Fairness/equity applied universally 14 10 Caring 44 21 Caring applied universally 28 4 Adapted from Oliner & Oliner, 1988 P R O S O C I A L B E H A v I O R n 575 community service such as working in homeless shelters or other community agen- cies also can be a way of gaining experience in helping others and deepening feel- ings of prosocial commitment (M. K. Johnson et al., 1998; Lawford et al., 2005; Pratt et al., 2003; Yates & Youniss, 1996). Participation in prosocial activities may also provide opportunities for children and adolescents to take others’ perspectives, to increase their confidence that they are competent to assist others, and to experience emotional rewards for helping. Even mandatory school-based service activities have been associated with future prosocial values (D. Hart et al., 2007), as well as with increased voluntary service at a later date for those high school youths who were not initially inclined to engage in such activities (Metz & Youniss, 2003). It should be noted, however, that forcing older adolescents or young adults into service activities can sometimes backfire and undermine their motivation to help (Stukas, Snyder, & Clary, 1999). Discipline and parenting style High levels of prosocial behavior and sympathy in children tend to be associated with constructive and supportive parenting, includ- ing authoritative parenting (Day & Padilla-Walker, 2009; Knafo & Plomin, 2006a; Michalik et al., 2007). When parents are involved with and close to their children, children are higher in sympathy and regulation, which in turn predicts higher levels of prosocial behavior (Padilla-Walker & Christensen, 2011). Parental support of, and attachment to, the child have been found to be especially predictive of prosocial behavior for youths who are low in fearfulness (Padilla-Walker & Nelson, 2010). It is important to note, however, that not only might supportive, authoritative parent- ing promote sympathy and prosocial behavior, but prosocial, sympathetic children might also elicit more support from their parents (Miklikowska, Duriez, & Soenens 2011; Padilla-Walker et al., 2012). In contrast, a parenting style that involves physi- cal punishment, threats, and an authoritarian approach (see Chapter 12) tends to be associated with a lack of sympathy and prosocial behavior in children (Asbury et al., 2003; Hastings et al., 2000; Krevans & Gibbs, 1996; Laible et al., 2008). The way in which parents attempt to directly elicit prosocial behavior from their children is also important. If children are regularly punished for fail- ing to engage in prosocial behavior, they may start to believe that the reason for helping others is primarily to avoid punishment (Dix & Grusec, 1983; M. L. Hoffman, 1983). Similarly, if children are given material rewards for prosocial behaviors, they may come to believe that they helped solely for the rewards and, thus, may be less motivated to help when no rewards are offered (Fabes et al., 1989; Warneken & Tomasello, 2008). What does seem particularly likely to foster chil- dren’s voluntary prosocial behavior is discipline that involves reasoning (Carlo, Mestre et al., 2010). This is especially true when the reasoning points out the con- sequences of the child’s behavior for others (Krevans & Gibbs, 1996), encourages perspective taking (B. M. Farrant et al., 2012), and is used by parents who gener- ally are warm and supportive (M. L. Hoffman, 1963). Such reasoning also encourages sympathy with others and provides guidelines children can refer to in future situations (C. S. Henry, Sager, & Plunkett, 1996; M. L. Hoffman, 1983). Maternal use of reasoning (e.g., “Can’t you see that Tim is hurt?”) seems to increase prosocial When adults point out the consequences of a child’s transgressions for others, children are more likely to respond with sympathy and prosocial behavior in other situations (N. eisenberg & Fabes, 1998; Krevans & Gibbs, 1996). S U S IE F IT Z H U G H 576 n CHApter 14 MORAL DEvELOPMENT behavior even for 1- to 2-year-olds, as long as mothers state their reasoning in an emotional tone of voice (Zahn-Waxler et al., 1979). Emotion in the mother’s voice likely catches her toddler’s attention and communicates that she is very serious about what she is saying. The combination of parental warmth and certain parenting practices—not parental warmth by itself—seems to be especially effective for fostering pro- social tendencies in children. Thus, children tend to be more prosocial when their parents are not only warm and supportive but also model prosocial behav- ior, include reasoning and references to moral values and responsibilities in their discipline, and expose their children to prosocial models and activities (i.e., use authoritative parenting; Hastings et al., 2007; Janssens & Dekovic, 1997; Yarrow et al., 1973). Because most of the research on the socialization of prosocial responding is correlational in design, it does not allow firm conclusions about cause-and- effect relations. However, some school interventions have been effective at promot- ing prosocial behavior in children, so environmental factors must contribute to its development (see Box 14.2). The research underlying such interventions indicates that experience in helping and cooperating with others, exposure to prosocial values and behaviors, and adults’ use of reasoning in discipline jointly contribute to the development of prosocial behavior. BOX 14.2: applications SCHOOL-BASED INTERVENTIONS FOR PROMOTING PROSOCIAL BEHAVIOR Knowledge about the socialization of help- ing and sharing behavior has been used to design school interventions aimed at foster- ing such behavior. Perhaps the most ambi- tious of these interventions was the Child Development Project in the East Bay area of San Francisco (Battistich et al., 1991; Battistich et al., 1997). This longitudinal intervention, which followed children across elementary school, trained teachers in pro- viding opportunities for children to develop a prosocial orientation toward their classmates and the community. The training focused on getting children to do the following: 1. Collaborate with others to achieve com- mon academic and social goals 2. Develop and practice important social competencies such as understanding of others’ thoughts and feelings 3. Provide meaningful help to others and receive help when it was needed 4. Discuss and reflect upon the degree to which their own and others’ behavior reflects fairness, concern and respect for others, and social responsibility 5. Participate in decision making about classroom norms, rules, and activities and take on responsibility for appropri- ate aspects of classroom life The program has led to increases in spon- taneous prosocial behavior, prosocial moral reasoning, and conflict-resolution skills (D. Solomon, Battistich, & Watson, 1993; D. Solomon et al., 1988). However, some programs involving a shorter period (a year or a limited number of lessons) and a focus on empathy training, anger management, impulse control, and problem solving have produced more limited evidence of improve- ments in empathy or prosocial behavior— that is, improvements on some measures such as self- or teacher-reports but not on peers’ reports or observed behavior, or at one school but not another (Cooke et al., 2007; S. D. McMahon & Washburn, 2003). Programs are probably most effective when sustained and well integrated into numerous aspects of school programs. The concept of the school as a caring community becomes a central part of simi- lar interventions. The caring school commu- nity is one in which teachers and students (1) care about and support one another; (2) share common values, norms, goals, and a sense of belonging; and (3) participate in and influence group decisions. Programs de- signed to promote caring school communi- ties included many of the components of the original Child Development Project. Findings with diverse samples of children suggest that enhancing a sense of school commu- nity not only promotes children’s concern for others, fostering prosocial behavior, conflict- resolution skills, and ethical attitudes and values; it also increases academic motiva- tion and liking of school and is associated with fewer problem behaviors and less use of drugs (Battistich et al., 1997; Battistich et al., 2000; Battistich, Schaps, & Wilson, 2004; D. Solomon et al., 2000). A N T I S O C I A L B E H A v I O R n 577 review: Prosocial behaviors emerge by the second year of life and increase in frequency during the toddler years. At least some types of prosocial behavior continue to increase in frequency and sensitivity in the preschool years and elementary school years. Early individual differences in prosocial behavior predict differences among children in these types of behaviors years later. Prosocial behavior may increase with age in childhood partly because of children’s devel- oping abilities to sympathize and take others’ perspectives. Differences among children in their empathy, sympathy, distress reactions to others’ distress, and perspective taking also contribute to individual differences in children’s prosocial behavior. Furthermore, biological factors, which may contribute to differences among children in temperament, likely affect how empathic and prosocial children become. The development of prosocial behavior also is related to children’s upbringing. In general, a positive relationship between parents and children is linked to prosocial moral develop- ment, especially when supportive parents use effective parenting practices. Authoritative, positive discipline—including the use of reasoning by parents and teachers and exposure to prosocial models, values, and activities—is associated with the development of sympathy and prosocial behavior. Cultures differ in the degree to which they value and teach prosocial behavior, and these differences are reflected in how much children help, share with, and are concerned about other people and perhaps whom they assist. Intervention programs in schools designed to foster prosocial behavior sometimes have been found to increase children’s prosocial behavior and prosocial moral reasoning; whether a given intervention is effective probably depends on its content, length, and the degree to which it is effectively administered. Such findings convincingly demonstrate that social fac- tors (as well as heredity) contribute to the development of prosocial tendencies. Antisocial Behavior Pick up any newspaper and you are inevitably reminded of the antisocial, often vio- lent behavior that is commonplace among youth in urban, industrialized countries, especially in Western societies. In the United States in 2009, juveniles younger than 18 were involved in 9% of murder arrests, 12% of aggravated assault arrests, 25% of burglary arrests, 25% of robbery arrests, 14% of rapes, 15% of all violent crimes, and 24% of all property crimes (Puzzanchera, Adams, & Hockenberry, 2012). Because youths are easier to arrest than adults are, these statistics likely over - estimate their criminal behavior. However, in cases that were closed, juveniles were involved in 11% of all violent crime, including 5% of murders and 11% of rapes, and 15% of all property crime (Puzzanchera et al., 2012). Statistics like these, along with incidents like the Columbine tragedy described at the beginning of the chap- ter, raise questions such as: Are youths who commit violent acts already aggressive in childhood? How do levels of aggression change with development? What factors contribute to individual differences in children’s antisocial behavior? As we address these issues, the themes of individual differences, nature and nurture, the sociocultural context, and research and children’s welfare will be particularly salient. The Development of Aggression and Other Antisocial Behaviors Aggression is behavior aimed at harming others (Parke & Slaby, 1983), and it is behavior that emerges quite early. How early? Instances of aggression over the possession of objects occur between infants before 12 months of age—especially behaviors such as trying to tug objects away from each other (D. F. Hay, Mundy aggression n behavior aimed at harming or injuring others 578 n CHApter 14 MORAL DEvELOPMENT et al., 2011)—but most do not involve bodily contact such as hitting (Coie & Dodge, 1998; D. F. Hay & Ross, 1982). Beginning at around 18 months of age, physical aggression such as hitting and pushing—particularly over the possession of objects—increases in frequency until about age 2 or 3 (Alink et al., 2006; D. F. Hay, Hurst et al., 2011; D. S. Shaw et al., 2003). Then, with the growth of language skills, physical aggression decreases in frequency, and verbal aggression such as insults and taunting increases (Bonica et al., 2003; Dionne et al., 2003; Mesman et al., 2009; Miner & Clarke-Stewart, 2008). Among the most frequent causes of aggression in the preschool years are conflicts between peers over possessions (Fabes & Eisenberg, 1992; Shantz, 1987) and conflict between siblings over most anything (Abramovitch, Corter, & Lando, 1979). Conflict over possessions often is an example of instrumental aggression, that is, aggression motivated by the desire to obtain a concrete goal, such as gain- ing possession of a toy or getting a better place in line. Pre- school children sometimes also use relational aggression (Crick, Casas, & Mosher, 1997), which, as explained in Chapter 13, is intended to harm others by damaging their peer relationships. Among preschoolers, this typically involves excluding peers from a play activity or a social group (M. K. Underwood, 2003). The drop in physical aggression in the preschool years is likely due to a variety of factors, including not only children’s increasing ability to use verbal and relational aggression but also their developing ability to use language to resolve conflicts and to control their own emotions and actions (Coie & Dodge, 1998). Thus, overt physical aggression continues to remain low or to decline in frequency for most children during elementary school, although a relatively small group of children—primarily boys (Moffitt & Caspi, 2001; NICHD Early Child Care Research Network, 2004)—develop fre- quent and serious problems with aggression and antisocial behavior at this age (Cairns et al., 1989; S. B. Campbell et al., 2010; D. S. Shaw et al., 2003) or in early adolescence (Xie, Drabick, & Chen, 2011). Whereas aggression in young children is usually instrumental, aggression in elementary school children often is hostile, arising from the desire to hurt another person or the need to protect oneself against a perceived threat to self- esteem (Dodge, 1980; Hartup, 1974). Children who engage in physical aggression tend to also engage in relational aggression (Card et al., 2008), with the degree to which they use one or the other tending to be consistent across childhood (Ostrov et al., 2008; Vaillancourt et al., 2003). Overall, the frequency of overt aggression decreases for most teenagers (Di Giunta et al., 2010; Loeber, 1982), at least after mid- adolescence (Karriker-Jaffe et al., 2008). In childhood, covert types of antisocial behaviors such as stealing, lying, and cheating also occur with considerable frequency and begin to be characteristic of some children with behavioral problems (Loeber & Schmaling, 1985). Compared with overt antisocial behavior, a high level of such covert behavior in the early school years has been found to be an even better predictor of a range of antisocial behavior 3 to 4 years later ( J. J. Snyder et al., 2012). In mid-adolescence, serious acts of violence increase markedly, as do property offenses and status offenses such as drinking and truancy (Lahey et al., 2000). As illustrated in Figure 14.3, adolescent violent crime peaks at age 17, when 29% of males and 12% of females report committing at least one serious violent Aggressive conflicts over objects are very common among young children. M Y R LE E N P E A R S O N / P H O T O E D IT instrumental aggression n aggression motivated by the desire to obtain a con- crete goal A N T I S O C I A L B E H A v I O R n 579 offense. As the figure also shows, male adolescents and adults engage in much more violent behavior and crime than do females (Coie & Dodge, 1998; Elliott, 1994)—although in 2009, 29% of the arrests among juveniles were of females (Puzzanchera, 2009), who made up 17% of the juvenile arrests for violent crime and 35% of the juvenile arrests for property crime. Consistency of Aggressive and Antisocial Behavior There is considerable consistency in both girls’ and boys’ aggression across child- hood and adolescence. Children who are the most aggressive and prone to con- duct problems such as stealing in middle childhood tend to be more aggressive and delinquent in adolescence than children who develop conduct problems at a later age (Broidy et al., 2003; Burt et al., 2000; Lahey, Goodman et al., 1999; Schaeffer et al., 2003). This holds especially true for boys (Fontaine et al., 2009). In one study, children who had been identified as aggressive by their peers when they were 8 years old had more criminal convictions and engaged in more seri- ous criminal behavior at age 30 than did those who had not been identified as aggressive (see Figure 14.4) (Eron et al., 1987). In another study of girls only, relational aggression in childhood was related to subsequent conduct disorders (Keenan et al., 2010). (Conduct disorders are discussed in Box 14.3.) Many children who are aggressive from early in life have neurological deficits (i.e., brain dysfunctions) that underlie such problems as difficulty in paying attention and hyperactivity (Gatzke-Kopp et al., 2009; Moffitt, 1993a; Speltz et al., 1999; Viding & McCrory, 2012). These deficits, which may become more marked with age (Aguilar et al., 2000), can result in troubled relations with parents, peers, and teachers that further fuel the child’s aggressive, antisocial pattern of behavior. Problems with attention are particularly likely to have this effect because they make it difficult for aggressive children to carefully consider all the relevant information in a social situation before deciding how to act; thus, their behavior often is 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 Age in years Males 30% 25% 20% 15% 10% 5% 0% A ge -s p ec if ic p re va le n ce Females FIGURE 14.3 prevalence of self- reported violence for males and females at different ages At all ages, males report enacting more violence than do females. (Adapted from Coie & Dodge, 1998) Males Females Low Medium High Low Medium High Age 8 aggression group 190 180 170 160 150 A ge 3 0 a gg re ss io n s co re FIGURE 14.4 the relation of peer- nominated aggression at age 8 to self- reported aggression at age 30 Boys and girls who were nominated as high in aggres- sion at age 8 were higher in self-reported aggression at age 30 than were their peers who had been nominated as lower in aggres- sion. (Adapted from eron et al., 1987) 580 n CHApter 14 MORAL DEvELOPMENT inappropriate for the situation. In addition, callous, unemotional traits, which often accompany aggression and conduct disorder (e.g., Keenan et al., 2010), appear to be associated with a delay in cortical maturation in brain areas involved in decision making, morality, and empathy (De Brito et al., 2009). Early-onset conduct problems are also associated with a range of family risk fac- tors. These include the mother’s being single at birth, the mother’s being stressed BOX 14.3: a closer look OPPOSITIONAL DEFIANT DISORDER AND CONDUCT DISORDER If a child’s problem behaviors become se- rious, the child is likely to be diagnosed by psychologists and physicians as hav- ing a clinical disorder. Two such disorders that involve antisocial behavior are opposi- tional defiant disorder and conduct disorder. Oppositional defiant disorder (ODD) is char- acterized by angry, defiant behavior that is age-inappropriate and persistent (lasting at least 6 months). Children with ODD typically lose their temper easily, arguing with adults and actively defying their requests or rules. They are also prone to blame others for their own mistakes or misbehavior and are often spiteful or vindictive. Conduct disorder (CD) includes more severe antisocial and aggres- sion behaviors that inflict pain on others (e.g., initiating fights, cruelty to animals) or involve the destruction of property or the violation of the rights of others (e.g., stealing, robberies). Other diagnostic signs include frequently running away from home, frequently staying out all night before age 13 despite paren- tal prohibitions, or persistent school tru- ancy beginning prior to age 13. To warrant a diagnosis of ODD or CD, children must exhibit multiple, persistent symptoms that are clearly impairing, distinguishing them from those youngsters who display the desig- nated behaviors on an infrequent or inconsis- tent basis (American Psychiatric Association, 1994; Hinshaw & Lee, 2003). There is debate in the field regarding how antisocial behavior, including ODD and CD, should be conceptualized. Some experts argue that antisocial behavior should be viewed in terms of a continuum from infrequent to frequent displays of external- izing symptoms. Others argue that extreme forms of antisocial behavior are qualitatively different from garden-variety types of ex- ternalizing behaviors. In other words, there is a question regarding whether children with ODD or CD simply have more, or more severe, externalizing problems than do bet- ter-adjusted youth, or whether their problems are of an altogether different type. The an- swer to this question is not clear. However, the fact that more externalizing symptoms at a younger age predict serious diagnosed problems in adolescence or adulthood (Biederman et al., 2008; Côté et al., 2001; Hinshaw & Lee, 2003) is viewed by some as evidence that serious externalizing problems differ in their origins from less severe types of such behavior. Estimates of the prevalence of ODD and CD range widely (Hinshaw & Lee, 2003). A median prevalence estimate for ODD among U.S. youth is about 3% (Lahey, Goodman et al., 1999). The American Psychiatric Asso- ciation (1994) has estimated that the rate of CD for children and adolescents is 6% to 16% for boys and 2% to 9% for girls. In one large study in Canada, the rates were approx- imately 8% for boys and 3% for girls (Offord, Alder, & Boyle, 1986). The average age of onset for ODD is approximately 6 years of age; for CD it is 9 years of age (Hinshaw & Lee, 2003). For girls, the onset of CD after age 9 is perhaps 10% (Keenan et al., 2010). Although there is debate in regard to the relation between ODD and CD, some chil- dren develop both CD and ODD, whereas others do not. A minority of youth with ODD later develop CD; however, those children or adolescents with CD often, but not always, had ODD first (Loeber & Burke, 2011; van Lier et al., 2007). In many instances, youth with ODD or CD also have been diagnosed with other disorders such as anxiety disor- der or attention-deficit hyperactivity dis order (about half of youth with ODD or CD also have attention-deficit hyperactivity disorder) (Hinshaw & Lee, 2003). The two disorders also seem to differ somewhat in their predic- tion of later problem behaviors: CD has been found to predict primarily behavioral prob- lems in early adulthood, including antisocial behavior, whereas ODD shows stronger pre- diction of emotional disorders in early adult- hood (Loeber & Burke, 2011; R. Rowe et al., 2010). The factors related to the development of CD or ODD are similar to those related to the development of aggression. Genetics play a role, although heritability seems to be stronger for early-onset and overt types of antisocial behavior (such as aggression) than for later-onset or covert forms of anti- social behavior (such as stealing) (Hinshaw & Lee, 2003; Lahey, Goodman et al., 2009; Maes et al., 2007; Meier et al., 2011). Environmental risks for these disorders in- clude such factors as living in a disadvantaged, risky neighborhood or in a stressed, lower- SES family; parental abuse; poor parental supervision; and harsh and inconsistent dis- cipline (Goodnight et al., 2012; Hinshaw & Lee, 2003; R. Rowe et al., 2010). Peer rejection and associating with deviant peers are also linked with ODD and CD (Hinshaw & Lee, 2003; Loeber & Stouthamer-Loeber, 1986). It is likely that a variety of these fac- tors jointly contribute to children’s developing ODD or CD and that the most important fac- tors vary according to the age of onset, the specific problem behaviors, and individual characteristics of the children, including their temperament and intelligence. oppositional defiant disorder (ODD) n a disorder characterized by age- inappropriate and persistent displays of angry, defiant, and irritable behaviors conduct disorder (CD) n a disorder that involves severe antisocial and aggression behaviors that inflict pain on others or involve destruction of property or denial of the rights of others A N T I S O C I A L B E H A v I O R n 581 prenatally and during the child’s preschool years; the mother’s being psychologi- cally unavailable in the preschool years; parental antisocial tendencies; low maternal education and poverty; and child neglect and physical abuse (S. B. Campbell et al., 2010; D. F. Hay et al., 2011; K. M. McCabe et al., 2001; NICHD Early Child Care Research Network, 2004; M. Robinson et al., 2011). Adolescents with a long childhood history of troubled behavior represent only a minority of adolescents who engage in the much broader problem of “juvenile delinquency” (Hämäläinen & Pulkkinen, 1996). Indeed, most adolescents who perform delinquent acts have no history of aggression or antisocial behavior before age 11 (Elliott, 1994). For some, delinquency may occur in response to the normal pressures of adolescence, as when they attempt to assert their independence from adults or win acceptance from their peers. However, the onset of antisocial behav- ior in adolescence is also predicted by economic disadvantage, being a member of an ethnic minority, interacting with deviant peers (see Chapter 13), and having a difficult, irritable temperament from infancy onward (K. M. McCabe et al., 2001, 2004; Roisman et al., 2010). Youths who develop problem behaviors in adolescence typically stop engaging in antisocial behavior later in adolescence or early adulthood (Moffitt, 1993a). However, some—especially those who have low impulse control, poor regulation of aggression, and a weak orientation toward the future (Monahan et al., 2009)— continue to engage in problem behaviors and to have some problems with their mental health and substance dependence until at least their mid-20s (Moffitt et al., 2002). Characteristics of Aggressive-Antisocial Children and Adolescents Aggressive-antisocial children and adolescents differ, on average, from their nonag- gressive peers in a variety of characteristics. These include having a difficult tem- perament and the tendency to process social information in negative ways. Temperament and Personality Children who develop problems with aggression and antisocial behavior tend to exhibit a difficult temperament and a lack of self-regulatory skills from a very early age (Espy et al., 2011; Rothbart, 2012; Yaman et al., 2010). Longitudinal studies have shown, for example, that infants and toddlers who frequently express intense negative emotion and demand much attention tend to have higher levels of prob- lem behaviors such as aggression from the preschool years through high school ( J. E. Bates et al., 1991; Joussemet et al., 2008; Olson et al., 2000). Similarly, pre- schoolers who exhibit lack of control, impulsivity, high activity level, irritability, and distractibility are prone to fighting, delinquency, and other antisocial behavior at ages 9 through 15; to aggression and criminal behavior in late adolescence; and, in the case of men, to violent crime in adulthood (Caspi et al., 1995; Caspi & Silva, 1995; Tremblay et al., 1994). However, children who use aggression to achieve in- strumental goals are less prone to unregulated negative emotion and physiological responding than those who exhibit angry responses to provocation (Scarpa et al., 2010; Vitaro et al., 2006). Some aggressive children and adolescents tend to feel neither guilt nor empathy or sympathy for others (de Wied et al., 2012; Lotze et al., 2010; R. J. McMahon, Witkiewitz, & Kotler, 2010; Pardini & Byrd, 2012; Stuewig et al., 2010). They are often charming, but insincere and callous. The combination 582 n CHApter 14 MORAL DEvELOPMENT of impulsivity, problems with attention, and callousness in childhood is especially likely to predict aggression, antisocial behavior, and run-ins with the police in adolescence (Christian et al., 1997; Frick & Morris, 2004; Hastings et al., 2000) and perhaps in adulthood as well (Lynam, 1996). Social Cognition In addition to their differences in temperament, aggressive children differ from nonaggressive children in their social cognition. As discussed in Chapter 9, aggressive children tend to interpret the world through an “aggressive” lens. They are more likely than nonaggressive children to attribute hostile motives to others in contexts in which the other person’s motives and intentions are unclear (the “hos- tile attributional bias”) (Dodge et al., 2006; Lansford et al., 2010; MacBrayer et al., 2003; D. A. Nelson, Mitchell, & Yang, 2008). Compared with those of nonaggres- sive peers, their goals in such social encounters are also more likely to be hostile and inappropriate to the situation, typically involving attempts to intimidate or get back at a peer (Crick & Dodge, 1994; Slaby & Guerra, 1988). Correspond- ingly, when asked to come up with possible solutions to a negative social situation, aggressive children generate fewer options than do nonaggressive children, and those options are more likely to involve aggressive or disruptive behavior (Deluty, 1985; Slaby & Guerra, 1988). In line with these tendencies, aggressive children are also inclined to evalu- ate aggressive responses more favorably, and competent, prosocial responses less favorably, than do their nonaggressive peers (Crick & Dodge, 1994; Dodge et al., 1986), especially as they get older (Fontaine et al., 2010). In part, this is because they feel more confident of their ability to perform acts of physical and verbal aggression (Barchia & Bussey, 2011; Quiggle et al., 1992), and they expect their aggressive behavior to result in positive outcomes (e.g., getting their way) as well as to reduce negative treatment by others (Dodge et al., 1986; Perry, Perry, & Rasmussen, 1986). Given all this, it is not surprising that aggressive children are predisposed to aggressive behavioral choices (Calvete & Orue, 2012; Dodge et al., 2006). This aggressive behavior, in turn, appears to increase children’s subse- quent tendency to positively evaluate aggressive interpersonal behaviors, further increasing the level of future antisocial conduct (Fontaine et al., 2008). It is important to note, however, that although all these aspects of functioning contribute to the prediction of children’s aggression, not all aggressive children exhibit the same biases in social cognition. Children who are prone to emotion- ally driven, hostile aggression—labeled reactive aggression—are particularly likely to perceive others’ motives as hostile (Crick & Dodge, 1996), to initially generate aggressive responses to provocation, and to evaluate their responses as morally acceptable (Arsenio, Adams, & Gold, 2009; Dodge et al., 1997). In con- trast, children who are prone to proactive aggression—which, like instrumental aggression, is aimed at fulfilling a need or desire—tend to anticipate more posi- tive social consequences for aggression (Arsenio , Adams, & Gold, 2009; Crick & Dodge, 1996; Dodge et al., 1997; Sijtsema et al., 2009). The Origins of Aggression What are the causes of aggression in children? Key contributors include genetic makeup, socialization by family members, the influence of peers, and cultural factors. reactive aggression n emotionally driven, antagonistic aggression sparked by one’s perception that other people’s motives are hostile proactive aggression n unemotional aggression aimed at fulfilling a need or desire proactive aggression (purposeful aggression not evoked by emotion) is used by children to bully others and to get what they want from them. B U B B LE S P H O T O LI B R A R Y / A LA M Y A N T I S O C I A L B E H A v I O R n 583 Biological Factors Biological factors undoubtedly contribute to individual differences in aggression, but their precise role is not very clear. Twin studies suggest that antisocial behavior runs in families and is partially due to genetic factors (Arsenault et al., 2003; Rhee & Waldman, 2002; Waldman et al., 2011). In addition, heredity appears to play a stron- ger role in aggression in early childhood and adulthood than it does in adolescence, when environmental factors are a major contributor to aggression (Rende & Plomin, 1995; J. Taylor, Iacono, & McGue, 2000). Heredity also contributes to both proactive and reactive aggression, but in terms of stability of individual differences in aggres- sion and the association of aggression with psychopathic traits (e.g., callousness, lack of affect, including lack of remorse, and manipulativeness), the influence of heredity is greater for proactive aggression (Bezdjian et al., 2011; Tuvblad et al., 2009). We have already noted one genetically influenced contributor to aggression—dif- ficult temperament. Hormonal factors are also assumed to play a role in aggression, although the evidence for this assumption is mixed. For example, testosterone levels seem to be related to activity level and responses to provocation, and high testosterone levels sometimes have been linked to aggressive behavior (Archer, 1991; Hermans, Ramsey, & van Honk, 2008). However, the relation of testosterone to aggression, al- though statistically significant, is quite small (Book, Starzyk, & Quinsey, 2001). Another biological contributor to aggression discussed earlier is neurological defi- cits that affect attention and regulatory capabilities (Moffitt, 1993b): children who are not well regulated are likely to have difficulty controlling their tempers and inhibiting aggressive impulses (N. Eisenberg, Spinrad, & Eggum, 2010; N. Eisenberg, Valiente et al., 2009; Y. Xu, Farver, & Zhang, 2009). Whatever their specific role, the biological correlates of aggression probably are neither necessary nor sufficient to cause aggressive behavior in most children. Genetic, neurological, or hormonal characteristics may put a child at risk for devel- oping aggressive and antisocial behavior, but whether the child becomes aggressive will depend on numerous factors, including experiences in the social world. We return to the joint role of genetics and the environment in aggression shortly. Socialization of Aggression and Antisocial Behavior Many people, including some legislators and judges, feel that the development of aggression can be traced back to socialization in the home. And, in fact, the quality of parenting experienced by antisocial children is poorer than that experienced by other children (Dodge et al., 2006; Scaramella et al., 2002). For example, children in chaotic homes—characterized by a lack of order and structure, few predictable routines, and noise—tend to be relatively high in disruptive behavior, and this rela- tion appears not to be due to genetics ( Jaffee et al., 2012). Although it is unclear to what degree poor parenting and chaotic homes, in and of themselves, may account for children’s antisocial behavior, it is clear that they comprise several factors that can promote such behavior. parental punitiveness Many children whose parents often use harsh but non- abusive physical punishment are prone to problem behaviors in the early years, aggression in childhood, and criminality in adolescence and adulthood (Burnette et al., 2012; Gershoff, 2002; Gershoff et al., 2010; Gershoff et al., 2012; Olson et al., 2011). This is especially true when the parents are cold and punitive in general (Deater-Deckard & Dodge, 1997), when the child does not have an early secure attachment (Kochanska et al., 2009; Kochanska & Kim, 2012), and when the child 584 n CHApter 14 MORAL DEvELOPMENT has a difficult temperament and is chronically angry and unregulated (Kochanska & Kim, 2012; Mulvaney & Mebert, 2007; Y. Xu et al., 2009; Yaman et al., 2010). It is important to note, however, that the relation between physical punishment and children’s antisocial behavior varies across racial, ethnic, and cultural groups. As discussed in Chapter 12, in some cultures and subcultures, physical punishment and controlling parental behaviors are viewed as part of responsible parenting when cou- pled with parental support and normal demands for compliance. When this is the case, parental punishment tends not to be associated with antisocial behavior because children might see authoritarian parenting as protective and caring (Lansford et al., 2006). Although corporal punishment, as well as yelling and screaming, tends to be associated with higher levels of aggression in children in a number of diverse cul- tures, including China, India, Kenya, Italy, Philippines, and Thailand, this relation is weaker if children view such parenting as normative (Gershoff et al., 2010). In contrast, abusive punishment is likely to be associated with the development of antisocial tendencies regardless of the group in question (Deater-Deckard et al., 1995; Luntz & Widom, 1994; Weiss et al., 1992). Very harsh physical discipline appears to lead to the kinds of social cognition that are associated with aggression, such as assuming that others have hostile intentions, generating aggressive solu- tions to interpersonal problems, and expecting aggressive behavior to result in posi- tive outcomes (Alink et al., 2012; Dodge et al., 1995). In addition, parents who use abusive punishment provide salient models of aggressive behavior for their children to imitate (Dogan et al., 2007). Ironically, children who are subjected to such punishment are likely to be anxious or angry and therefore are unlikely to attend to their parents’ instructions or demands or to be motivated to behave as their parents wish them to (M. L. Hoffman, 1983). There probably is a reciprocal relation between children’s behavior and their parents’ punitive discipline (Arim et al., 2011; N. Eisenberg, Fabes et al., 1999). That is, children who are high in antisocial behavior, exhibit psychopathic traits (e.g., are callous, unemotional, manipulative, remorseless), or are low in self-regulation tend to elicit harsh parenting (Lansford et al., 2009; Salihovic et al., 2012); in turn, harsh parenting increases the children’s problem be- havior (Sheehan & Watson, 2008). However, some recent research suggests that harsh physical punishment has a stronger effect on chil- dren’s externalizing problems than vice versa (Lansford et al., 2011). The relation between punitive parenting and children’s aggres- sion can, of course, have a genetic component. Parents whose chil- dren are antisocial and aggressive often are that way themselves and are predisposed to punitive parenting (Davies et al., 2012; Dogan et al., 2007; Thornberry et al., 2003). At the same time, however, twin studies indicate that the relation between punitive, negative parent- ing and children’s aggression and antisocial behavior is not entirely due to hereditary factors (Boutwell et al., 2011; Jaffee et al., 2004a; Jaffee et al., 2004b). In one study, for example, differences in punitive parenting with adolescent identical twins were related to differences in the twins’ aggression (Caspi et al., 2004). In another study, parent–adolescent conflict predicted more conduct problems over time (but not vice versa), even in adoptive families (Klahr et al., 2011). In neither of these studies can genetics explain the effects of parents’ behaviors on their children’s problem behaviors. Ineffective discipline and family coercion Another factor that can increase children’s antisocial behavior is ineffective parenting. Parents who are inconsistent there is probably a reciprocal relation between children’s behavior and their par- ents’ punitive discipline. that is, children who are high in antisocial behavior or low in self-regulation tend to elicit harsher par- enting. the harsher parenting in turn elicits more problematic behavior from the child. A C E S T O C K L IM IT E D / A LA M Y A N T I S O C I A L B E H A v I O R n 585 in administering discipline are more likely than other parents to have aggressive and delinquent children (Dumka et al., 1997; Frick, Christian, & Wootton, 1999; Sampson & Laub, 1994). So too are parents who fail to monitor their children’s behavior and activities. One reason parental monitoring may be important is that it reduces the likelihood that older children and adolescents will associate with devi- ant, antisocial peers (Dodge et al., 2008; G. R. Patterson, Capaldi, & Bank, 1991). It also makes it more likely that parents will know if their children are engaging in antisocial behavior. At the same time, however, parents of difficult, aggressive youth sometimes find that monitoring leads to such conflict with their children that they are forced to back off (Laird et al., 2003). Ineffective discipline is often evident in the pattern of troubled family interac- tion described by G. R. Patterson (1982, 1995; J. Snyder et al., 2005) and discussed in Chapter 1. In this pattern, the aggression of children who are out of control may be unintentionally reinforced by parents who, once their efforts to coerce compli- ance have failed, give in to their children’s fits of temper and demands ( J. Snyder, Reid, & Patterson, 2003). This is especially probable in the case of out-of-control boys, who are much more likely than other boys to react negatively to their mother’s attempts to discipline them (G. R. Patterson, Reid, & Dishion, 1992). Whether maternal coercion elicits the same pattern of response from girls as from boys is not yet known because most of the relevant research has been done with boys, but there is some reason to believe that it does not (McFadyen-Ketchum et al., 1996). parental conflict Children who are frequently exposed to verbal and physical violence between their parents tend to be more antisocial and aggressive than other children (Cummings & Davies, 2002; R. Feldman, Masalha, & Derdikman-Eiron, 2010; Keller et al., 2008; Van Ryzin & Dishion, 2012). This relation holds true even when genetic factors that might have caused it are taken into account ( Jaffee et al., 2002). One obvious reason for this is that embattled parents model aggressive behavior for their children. Another is that children whose mothers are physically abused tend to believe that violence is an acceptable, even natural part of family interactions (Graham-Bermann & Brescoll, 2000). Compared with spouses who get along well with each other, embattled spouses also tend to be less skilled and responsive, and more hos- tile and controlling, in their parenting (Buehler et al., 1997; Davies et al., 2012; Emery, 1989; Gonzales et al., 2000), which, in turn, can increase their children’s aggressive tendencies (Li et al., 2011). This pattern, in which marital hostility predicts hostile parenting, which, in turn, predicts children’s aggression, has also been found in families with an adopted child, so these relations cannot be due solely to genes shared by parents and children (Stover et al., 2012). Socioeconomic status and children’s anti social behavior Children from low- income families tend to be more antisocial and aggressive than children from more prosperous homes (Goodnight et al., 2012; Keiley et al., 2000; NICHD Early Child Care Research Network, 2004; Stouthamer-Loeber et al., 2002). This pat- tern is highlighted by the finding that when families escaped from poverty, 4- to 7-year-old children tended to become less aggressive and antisocial, whereas Children are more likely to develop aggres- sive and antisocial behavior if they are exposed to marital conflict, especially violence. parents who are in unhappy marriages tend to be withdrawn and nonsup- portive with their children, which appears to contribute to their children’s problems with adjustment. IS T O C K P H O T O / T H IN K S T O C K 586 n CHApter 14 MORAL DEvELOPMENT families’ remaining in poverty or moving into poverty for the long-term was associated with an increase in children’s antisocial behavior (Macmillan et al., 2004). There are many reasons that might account for such differences in trajectories. One major reason is the greater amount of stressors experienced by children in poor families, including stress in the family (illness, domestic violence, divorce, legal problems) and neighborhood violence (Vanfossen et al., 2010). In addition, as discussed in Chapter 12, low SES tends to be associated with living in a single- parent family or being an unplanned child of a teenage parent, and stressors of these sorts are linked to increased aggression and antisocial behavior (Dodge, Pettit, & Bates, 1994; Linares et al., 2001; Tolan, Gorman-Smith, & Henry, 2003; Trentacosta et al., 2008). Also, because of the many stressors they face, impover- ished parents are more likely than other parents to be rejecting and low in warmth; to use erratic, threatening, and harsh discipline; and to be lax in supervising their children (Conger et al., 1994; Dodge et al., 1994; Odgers et al., 2012). In addition to all these low-SES risk factors, conditions such as the presence of gangs, the lack of jobs for juveniles, and few opportunities to engage in constructive activities (e.g., clubs and sports) also likely contribute to the antisocial behavior of many youths in poor neighborhoods. Peer Influence As we discussed in Chapter 13, aggressive children tend to socialize with other aggres- sive children and often become more delinquent over time if they have close friends who are aggressive. Moreover, the expression of a genetic tendency toward aggression is stronger for individuals who have aggressive friends (Brendgen et al., 2008). The larger peer group with whom older children and adolescents socialize may influence aggression even more than their close friends do (Coie & Dodge, 1998). In one study, boys exposed to peers involved in overt antisocial behaviors, such as violence and the use of a weapon, were more than three times as likely as other boys to engage in such acts themselves (Keenan et al., 1995). Associating with delin- quent peers tends to increase delinquency because these peers model and reinforce antisocial behavior in the peer group. At the same time, participating in delinquent activities brings adolescents into contact with more delinquent peers (Dishion et al., 2010; Dishion et al., 2012; Lacourse et al., 2003; Thornberry et al., 1994). Although research findings vary somewhat, it appears that children’s susceptibility to peer pressure to become involved in antisocial behavior increases in the elementary school years, peaks at about 8th or 9th grade, and declines thereafter (Berndt, 1979; B. B. Brown, Clasen, & Eicher, 1986; Steinberg & Silverberg, 1986). Although not all adolescents are susceptible to negative peer influence (Allen, Porter, & McFar- land, 2006), even popular youth in early adolescence tend to increase participation in minor levels of drug use and delinquency if these behaviors are approved by peers (Allen et al., 2005). Peer approval of relational aggression increases in middle school, and students in peer groups supportive of relational aggression become increasingly aggressive (N. E. Werner & Hill, 2010). However, there are exceptions to this overall pattern that appear to be related to cultural factors. For example, Mexican American immigrant youth who are less acculturated, and therefore more tied to traditional val- ues, appear to be less susceptible to peer pressure toward antisocial behavior than are Mexican American children who are more acculturated. Thus, it may be that peers play less of a role in promoting antisocial behavior for adolescents who are embedded in a traditional culture oriented toward adults’ expectations (e.g., deference and cour- tesy toward adults and adherence to adult values) (Wall et al., 1993). A N T I S O C I A L B E H A v I O R n 587 Gangs An important peer influence on antisocial behavior can be membership in a gang. It was estimated that in the United States in 2010, there were 29,400 youth gangs with 756,000 active members (Egley & Howell, 2012). Most gangs are in metropolitan areas. In Los Angeles, for example, it is estimated that there are more than 450 gangs, with a combined total of 45,000 gang members (Los Angeles Police Department, 2013). However, since 1993, the presence of gangs in suburban and rural areas has increased (Egley & O’Donnell, 2009; H. N. Snyder & Sickmund, 1999; see Table 14.5). In many other countries, youth gangs are likewise becoming, or are likely to become, a serious problem (Vittori, 2007). Gangs tend to be composed of young people who are similar in ethnic and racial background. The average age of gang members is between 17 and 18 years, with about half being 18 or older and a small portion being as young as 12 (Egley & Howell, 2012). Adolescents are more likely to join gangs if they come from a neighborhood with a high rate of resident turnover, if they have an antisocial personality, and if they have psychopathic tendencies such as a combination of high hyperactivity, low anxiety, and low prosociality (Dupéré et al., 2007; Egan & Beadman, 2011). Adoles- cents who join gangs also tend to have engaged in antisocial activities and to have had delinquent friends before they joined. However, being in a gang appears to increase adolescents’ delinquent and antisocial behavior above their prior levels (Barnes, Beaver, & Miller, 2010; Delisi et al., 2009; Dishion et al., 2010; Lahey, Gordon et al., 1999). Not surprisingly, the longer adolescents remain in a gang, the more likely they are to engage in delinquent and an- tisocial behavior (Craig et al., 2002; Gordon et al., 2004). Teens who are gang members are responsible for much of the serious violence in the United States (Huizinga as cited in Howell, 1998). From 2009 to 2011 in Los Angeles, for example, there were more 16,000 verified violent gang crimes, including 491 homicides. Much of this violence involves conflict within and between gangs. and gang members are much more likely than the rest of the population to be victims of violent crime (e.g., killed, robbed, or attacked), apparently in part because of their high involvement in delinquent activities and their ready access to drugs and alcohol (Delisi et al., 2009; T. J. Taylor et al., 2007; T. J. Taylor et al., 2008). Because youths who join gangs usually do poorly in school (Dishion et al., 2010), many inner-city gang members continue their membership in gangs rather than entering into con- ventional adult roles (Decker & van Winkle, 1996; Short, 1996). Biology and Socialization: Their Joint Influence on Children’s Antisocial Behavior As should be clear by now, it is very difficult to separate the specific biological, cul- tural, peer, and familial factors that affect the development of children’s antisocial behavior (Van den Oord et al., 2000). Nonetheless, it is clear that parents’ treatment of their children affects children’s aggression and antisocial behavior. Direct evidence of the role of parental effects can be found in intervention studies. When parents are TABLE 14.5 Distribution of estimated Gangs and Gang Members by Area type in 2007 Gangs (%) Gang members (%) Rural counties 5.9 2.3 Smaller cities 33.5 16.8 Suburban counties 19.9 25.0 Larger cities 40.7 55.9 Total 100% 100% Source: Egley & O’Donnell, 2009 Gangs often provide youth with a sense of belonging, emblemized by specific gang signs. M A R K R IC H A R D S / P H O T O E D IT 588 n CHApter 14 MORAL DEvELOPMENT trained to deal with their children in an effective manner, there are improvements in their children’s conduct problems (A. Connell et al., 2008; Dishion et al., 2008; Hanish & Tolan, 2001). Similar effects have been obtained in intervention studies in schools (see Box 14.4). Effects such as these indicate that socialization in and of itself plays a role in the development of antisocial behavior. Nonetheless, recent genetically informed research illustrates that often it is the combination of genetic and environmental factors that predict children’s anti- social, aggressive behavior and that some children are more sensitive to the qual- ity of parenting than are others. As noted in our previous discussions of differen- tial susceptibility (pages 409, 437, and 569), children with certain gene variants related to serotonin or dopamine, which affect neurotransmission, appear to be more reactive to their environment than are children with different variants. For example, under adverse conditions (e.g., chronic stress, poor parenting, socioeco- nomic deprivation), children with a particular variant of the serotonin transporter gene (SLC6A4) or the dopamine receptor gene (DRD4) tend to be more aggres- sive than children with different variants of these gene (C. C. Conway et al., 2012) but, compared with those children, they tend to be less aggressive when they are in Psychologists interested in the prevention of antisocial behavior and violence have designed numerous school-based interven- tion programs. One of the most intensive was Fast Track—a large, federally funded study that was tested in high-risk schools in four U.S. cities (Conduct Problems Preven- tion Research Group, 1999a; 1999b). This program was initially implemented for 3 successive years with almost 400 1st-grade classes, half of which received the interven- tion and half of which served as a control group. The children in both groups tended to come from low-income families, about half of which were minority families (Slough, McMahon, & the Conduct Problems Preven- tion Research Group, 2008). There were two major parts of the inter- vention. In the first part, all children in the intervention classes were trained with a spe- cial curriculum designed to promote under- standing and communication of emotions, positive social behavior, self-control, and so- cial problem solving (Greenberg et al., 1995). The children were taught to recognize emo- tional cues in themselves and to distinguish appropriate and inappropriate behavioral re- actions to emotions. They were also taught how to make and keep friends, how to share, how to listen to others, and how to calm themselves down and to inhibit aggressive be- havior when they became upset or frustrated. In the second part of the program, chil- dren with the most serious problem behav- iors (about 10% of the group) participated in a more intensive intervention. In addition to the school intervention, they attended spe- cial meetings throughout the year, receiving social skills training similar to what they ex- perienced in the classroom. They were also tutored in their school work. Their parents received group training that was designed to build their self-control and promote develop- mentally appropriate expectations for their child’s behavior. In addition, the program pro- moted parenting skills that would improve parent–child interaction, decrease children’s disruptive behavior, and establish a positive relationship between parents and the child’s school. After 1st grade, the curriculum was continued in the classrooms; other aspects of the intervention outside the classroom were adjusted to the needs of each family and child (Conduct Problems Prevention Re- search Group, 2004). Meetings with children and parents continued through the 9th grade. The program was quite successful. In the 1st-grade classrooms as a whole, there was less aggression and disruptive behavior and a more positive atmosphere than in the control classes. More important, the children in the intervention group improved in their social and emotional skills (such as recognizing and coping with emotions), as well as in academic skills. They had more positive interactions with peers, were liked more by their class- mates, and exhibited fewer conduct problems than the control children. Their parents im- proved in their parenting skills and were more involved with their children’s schooling. In a follow-up at the end of 3rd grade, 37% of the children in the intervention group were found to be free of serious conduct problems, whereas only 27% of the children who did not receive the intervention were free of problems (Conduct Problems Preven- tion Research Group, 2002a). Teachers’ and parents’ reports, as well as school records, likewise indicated that there was a modest positive effect, both at home and in school, including the intervention group’s using spe- cial education services less and showing greater improvement in academic engage- ment. The intervention group also showed a BOX 14.4: applications THE FAST TRACK INTERVENTION A N T I S O C I A L B E H A v I O R n 589 a supportive, resource-rich environment (Simons et al., 2011; Simons et al., 2012). In other cases, such gene variants are related to higher risk for aggression in adverse situations like maltreatment and divorce, but are not related to aggression in the absence of the adverse conditions (Cicchetti, Rogosch, & Thibodeau, 2012; Ne- derhof et al., 2012). Regardless of the exact nature of the gene–environment inter- action, it seems clear that the degree of aggression is affected by a combination of heredity and the environment. review: Aggressive behavior emerges by the second year of life and increases in frequency during the toddler years. Physical aggression starts to decline in frequency in the preschool years; in elementary school, children tend to exhibit more nonphysical aggression (e.g., relational aggression) than at younger ages, and some children increasingly engage in antisocial behav- iors such as stealing. Early individual differences in aggression and conduct problems pre- dict antisocial behavior in later childhood, adolescence, and adulthood. Children who first engage in aggressive, antisocial acts in early to mid-adolescence are less likely to continue their antisocial behavior after adolescence than are children who are aggressive and anti- social at a younger age. modest increase in prosocial behavior. These effects generally were stronger in less disad- vantaged schools, and effects on aggression were larger in students who showed higher baseline levels of aggression. In 4th and 5th grades, children in the intervention group still exhibited modest improvements in terms of conduct problems, peer acceptance, and lower levels of association with deviant peers. These positive outcomes seemed to be due, in part, to the effects of the intervention on reducing children’s hostile attribution biases, fostering their problem-solving skills, and reducing the levels of harsh parental dis- cipline (Conduct Problems Prevention Re- search Group, 2002b, 2004; Bierman et al., 2010). Across grades 3 to 12, the prevalence of externalizing problems such as conduct dis- order, oppositional defiant disorder, and attention-deficit hyperactivity disorder was reduced, although only for the youths most at risk (Conduct Problems Prevention Research Group, 2007, 2011). In addition, juvenile arrests were reduced, as were high-severity arrests in early adulthood for youths with the highest initial behavioral risk (Conduct Prob- lems Prevention Research Group, 2010c). In terms of cost, it appears that, given the funds available, the program was not cost-efficient relative to the total sample but was likely cost-effective for the subgroup of children at high risk for externalizing problems (Foster & Jones, 2007). Thus, it is important that chil- dren be screened for inclusion in high-cost programs such as Fast Track (Conduct Prob- lems Prevention Research Group, 2007). Many interventions besides Fast Track have been devised to reduce children’s ag- gression and other externalizing problems. For example, numerous programs have been used to combat bullying in schools and the high-quality programs appear to reduce the incidence of bullying considerably (Cross et al., 2011; Salmivalli, Kärnä, & Poskiparta, 2011; Ttofi & Farrington, 2011). More intensive programs tend to be more effec- tive, and the most important elements of successful programs included parent meet- ings and training; teacher training and an emphasis on classroom management; firm disciplinary practices at school, including the enforcement of classroom rules; and a whole-school policy to eliminate bullying, improve playground supervision, and have children work in cooperative groups (Ttofi & Farrington, 2011). Anti-bullying interven- tions appear to be more effective for ado- lescents than for younger children (Ttofi & Farrington, 2011). Objectives of the Fast track project Target high-risk schools and Select first graders with pervasive conduct problems Promote competency in: Academic achievement Child coping/Problem solving Peer relations Parenting and socialization Home–school partnership Classroom atmosphere Reduce adolescent rates in: Antisocial activity Substance abuse Psychological problems School drop-out 590 n CHApter 14 MORAL DEvELOPMENT chapter summary: Moral Judgment n Piaget delineated two age-related moral stages and a transi- tional period. In the first stage, morality of constraint, young children tend to believe that rules are unchangeable and tend to weigh consequences more than intentions in evaluating the morality of actions. In the autonomous stage, children realize that rules are social products that can be changed, and they consider motives and intentions when evaluating behavior. Several aspects of Piaget’s theory have not held up well to scrutiny, but his theory provided the foundation for subsequent work on moral reasoning. n Kohlberg outlined three levels of moral judgment— preconventional, conventional, and postconventional— each originally containing two stages (Stage 6 was eventu- ally dropped from Kohlberg’s scoring procedure). Kohlberg hypothesized that his sequence of stages reflects age-related, discontinuous (qualitative) changes in moral reasoning that are universal. According to Kohlberg, these changes stem from cognitive advances, particularly in perspective taking. Although there is support for the idea that higher levels of moral reasoning are related to cognitive growth, it is not clear that children’s moral reasoning moves through discontinuous stages of development or develops the same way in all cul- tures and for all kinds of moral issues (e.g., prosocial moral reasoning). n There are important differences among the moral, social con- ventional, and personal domains of behavior and judgment. Young children, like older children, differentiate among dif- ferent domains of social judgment. Which behaviors are con- sidered matters of moral, social conventional, or personal judgment varies somewhat across cultures. The Early Development of Conscience n The conscience involves internalized moral standards and feelings of guilt for misbehavior: it restrains the individual from engaging in unacceptable behavior. The conscience develops slowly over time, beginning before age 2. Children are more likely to internalize parental standards if they are securely attached and if their parents do not rely on exces- sive parental power in their discipline, depending on their temperament. Prosocial Behavior n Prosocial behavior is voluntary behavior intended to ben- efit another, such as helping, sharing, and comforting others. Young children who are prosocial, especially those who spon- taneously engage in sharing that is personally costly, tend to be prosocial when older. n Prosocial behaviors emerge by the second year of life and increase in frequency with age, probably due to age-related increases in children’s abilities to sympathize and take others’ perspectives. Differences among children in these abilities con- tribute to individual differences in children’s prosocial behavior. n Heredity, which contributes to differences among children in temperament, likely affects how empathic and prosocial chil- dren are. n A positive parent–child relationship; authoritative parenting; the use of reasoning by parents and teachers; and exposure to prosocial models, values, and activities are associated with the development of sympathy and prosocial behavior. Cul- tural values and expectations also appear to affect the degree to which children exhibit prosocial behavior and toward whom. Biological factors, including those related to temperament and neurological problems, likely affect children’s degree of aggression. Social cognition is also associated with aggres- siveness in a variety of ways, including the attribution of hostile motives to others, having hostile goals, constructing and enacting aggressive responses in difficult situations, and evaluating aggressive responses favorably. Children’s aggression is affected by a range of environmental factors, as well as by heredity. In general, low parental support, poor monitoring, or the use of disciplinary prac- tices that are abusive or inconsistent are related to high levels of children’s antisocial behav- ior. Parental conflict in the home and many of the stresses associated with family transitions (e.g., divorce) and poverty can increase the likelihood of children’s aggression. In addition, involvement with antisocial peers likely contributes to antisocial behavior, although aggres- sive children also seek out antisocial peers. Cultural values and practices, as communicated in the child’s social world, also contribute to differences among children in aggressive behav- ior. Intervention programs can be used to reduce aggression, which provides evidence of the role of environmental factors in children’s aggression. C H A P T E R S U M M A R Y n 591 Critical Thinking Questions 1. Recall a recent moral dilemma in your own life. What sorts of reasoning did you use when thinking about the dilemma? On what dimensions did it differ from Kohlberg’s Heinz dilemma? How might these differences have affected your reasoning about this dilemma? 2. How would you design a study to determine why aggressive children and adolescents have aggressive friends? How would you determine whether aggressive youth simply choose aggressive friends or whether aggressive friends tend to make youth become more aggressive? 3. Suppose you wanted to assess children’s helping behavior that was altruistic and not due to factors such as the expectation of personal gain or concern about others’ approval. How would you design a study to assess altruistic helping in 5-year-olds? Might the procedure differ if you wanted to assess altruistic helping in 16-year-olds? 4. Freud believed that morality does not emerge until the child develops a superego at around 4 to 6 years of age. What evi- dence contradicts his theory? 5. Using the tenets of social learning theory (see Chapter 9), outline ways that parents might deter the development of aggression in their children. Key Terms aggression, p. 577 altruistic motives, p. 569 conduct disorder (CD), p. 580 conscience, p. 566 instrumental aggression, p. 578 moral judgments, p. 564 oppositional defiant disorder (ODD), p. 580 personal judgments, p. 564 proactive aggression, p. 582 prosocial behavior, p. 562 reactive aggression, p. 582 social conventional judgments, p. 564 n School-based intervention programs designed to promote cooperation, perspective taking, helping, and prosocial values are associated with increased prosocial tendencies in children. Antisocial Behavior n Aggressive behavior emerges by the second year of life and increases in frequency during the toddler years; physical aggression starts to decline in frequency in the preschool years. In elementary school, children tend to exhibit more nonphys- ical aggression (e.g., relational aggression) than at younger ages, and some children increasingly engage in antisocial behaviors such as stealing. n From preschool on, boys are more physically aggressive than girls and more likely to engage in delinquent behavior. n Early individual differences in aggression and conduct prob- lems predict antisocial behavior in later childhood, adoles- cence, and adulthood. n Biological factors that contribute to differences among chil- dren in temperament and neurological functioning likely affect how aggressive children become. Social cognition also affects aggression: aggressive children tend to attribute hostile motives to others and to have hostile goals themselves. n Children’s aggression is promoted by a range of environmental factors, including low parental support; chaotic families; poor monitoring; abusive, coercive, or inconsistent disciplining; and stress or conflict in the home. In addition, involvement with antisocial peers likely contributes to antisocial behavior, although it is also likely that aggressive children seek out anti- social peers. Aggression also varies somewhat across cultures, suggesting that cultural values, norms, and socialization prac- tices may also contribute to individual differences in aggression and antisocial behavior. n Children who are diagnosed with antisocial behavior such as conduct disorder and oppositional defiant disorder display rel- atively severe forms of problematic externalizing behaviors. n In high-risk schools, interventions designed to promote understanding and communication of emotions, positive social behavior, self-control, and social problem solving can reduce the likelihood that children will develop behavior problems, including aggression. 592 P R IV AT E C O LL E C T IO N / T H E B R ID G E M A N A R T L IB R A R Y P. J . C R O O K , Playground (acrylic on canvas) 593 chapter 15: Gender Development n Theoretical Approaches to Gender Development Biological Influences Box 15.1: A Closer Look Gender Identity: More than Socialization? Cognitive and Motivational Influences Box 15.2: A Closer Look Gender Typing at Home Box 15.3: Applications Where Are SpongeSally SquarePants and Curious Jane? Cultural Influences Review n Milestones in Gender Development Infancy and Toddlerhood Preschool Years Middle Childhood Adolescence Box 15.4: A Closer Look Gender Flexibility and Asymmetry Review n Comparing Girls and Boys Physical Growth: Prenatal Development Through Adolescence Cognitive Abilities and Academic Achievement Personality Traits Interpersonal Goals and Communication Box 15.5: A Closer Look Gender and Children’s Communication Style Aggressive Behavior Box 15.6: Applications Sexual Harassment and Dating Violence Review n Chapter Summary 594 O ne late autumn afternoon, the two children pictured below were playing in the backyard as their mothers, best friends for many years, were having tea on the deck. Colin, who was 5 years old, and Catherine, who was 4½, had played together since infancy. Even though they shared many of the same interests, they were also dif- ferent in many ways. For example, Catherine hated movies that were the least bit violent or scary: as a toddler, she would not even watch Sesame Street because she was frightened of Oscar the Grouch. When asked to pause in her play to be pho- tographed, Catherine happily complied and struck an expressive pose. In contrast, Colin loved action films full of car chases, fires, and explosions. His rifle and hel- met testified to his fascination with guns and the military. Colin initially resisted the request to be photographed. After finally agreeing, he took an aggressive stance holding his toy gun. Colin and Catherine exhibit some of the behavioral differences in assertion and affiliation that are often seen between boys and girls. Assertion refers to one’s attempts to exert influence over the environment, whereas affiliation refers to making connections with others. The traditional masculine role in most societies stresses self-assertion over interpersonal affiliation, with corresponding emphases on independence, competition, and task orientation. In contrast, the traditional feminine role stresses affiliation over assertion, with corresponding emphases on interpersonal sensitivity, supportiveness, and affection (Bassen & Lamb, 2006; Leaper & Smith, 2004). However, the goals of assertion and affiliation are not mutually exclusive: they are often blended to- gether in a style known as collaboration (Leaper, 1991; Leaper, Tenenbaum, & Shaffer, 1999). Collab- oration is associated with gender-role flexibility and, on average, is more common among girls than among boys. As with most gender differences, however, there is also, on average, considerable overlap between girls and boys in collaboration. Indeed, although some children act in gender-stereotypical ways, many girls and boys are, as you will soon see, quite similar to one another in a wide variety of behaviors. In this chapter, we consider what might account for gender differences or similarities between girls and boys. Why do they have different preferences? How representative is their behavior compared with other children of their gender? Do they consistently demon- strate gender-stereotypical behaviors across different situations? Developmental psychologists generally acknowledge the combined influ- ences of biological, psychological, and cultural processes on gender develop- ment (Leaper, 2013) but differ in how much they stress particular factors. Some researchers argue that certain differences in boys’ and girls’ behavior reflect underlying biological differences that emerged over the course of human evolu- tion (Bjorklund & Pellegrini, 2002; Geary, 1998). In their view, average gender differences in assertion and affiliation are partly attributable to genetic sex dif- ferences in brain structures and hormone effects. In contrast, other psychologists place more emphasis on social and cognitive influences (Bussey & Bandura, 1999; Themes n Nature and Nurture n The Active Child n The Sociocultural Context n Individual Differences assertion n tendency to take action on behalf of the self through competitive, independent, or aggressive behaviors affiliation n tendency to affirm connec- tion with others through being emotion- ally open, empathetic, or cooperative collaboration n coordination of asser- tion and affiliation in behavior, which is associated with gender-role flexibility and more common among girls than boys Although this boy and girl are similar in age, some differences in their behavior, atti- tudes, and interests are apparent. In this chapter, we compare girls’ and boys’ devel- opment and consider different theoretical perspectives on the development of gender differences. B O T H : C O U R T E S Y O F J U D Y D E LO A C H E T H E O R E T I C A L A P P R O A C H E S T O G E N D E R D E V E L O P M E N T n 595 C. L. Martin, Ruble, & Szkrybalo, 2002). In general, most developmental psy- chologists contend that the role of biology in the development of gender-related differences must be considered in the context of the social influences of family, peers, teachers, and the culture at large. We examine two main questions in this chapter: (1) How similar or different are girls and boys in terms of psychological variables? (2) What might account for any differences? We first consider the biological, cognitive-motivational, and cul- tural influences that may contribute to gender development. Next, we outline the major milestones in children’s development of gender stereotypes and gender-typed behavior. Then we compare what actually is known about the similarities and dif- ferences between girls and boys in specific areas of development, including physi- cal development, cognitive abilities and achievement, and personality and social behavior. Throughout our discussion, we use the terms sex and gender in distinct ways. Sex tends to imply biological origins for any differences between males and females. Therefore, we follow the convention of using gender as a more neutral term that refers simply to one’s social categorization as either female or male, and we use the term sex only when referring explicitly to biological processes, such as those involving sex hor- mones or genetic sex. In addition, the terms gender-typed and cross-gender-typed refer, respectively, to behaviors associated with a given person’s gender and to behav- iors associated with the gender other than that of a given person. For example, playing with dolls is gender-typed for girls and cross-gender-typed for boys. Finally, the term gender typing refers broadly to the process of gender socialization and development. Four of our seven themes are particularly prominent in this chapter. The theme of nature and nurture appears repeatedly, as perspectives vary in emphasizing the roles played by biological and environmental factors in gender development. The theme of the active child is apparent in cognitive theories of gender development that emphasize children’s roles in discovering what it means to be male or female and in socializing their peers into gender-appropriate roles. The sociocultural context is reflected in theories that emphasize the central roles that parents, teachers, peers, and the media play in shaping children’s gender development. Finally, the theme of individual differences also pervades the chapter as we attempt to account for the ways in which males and females are similar and different. Theoretical Approaches to Gender Development Researchers variously point to the influences of biological, cognitive-motivational, and cultural factors on gender development. First, biological differences between females and males—including the influence of sex hormones and brain structure differences—may partly account for average gender differences in some behav- iors. Second, cognition and motivation—learning gender-typed roles through observation and practice—can shape children’s gender development. As high- lighted in cognitive-motivational explanations, boys and girls are systematically provided different role models, opportunities, and incentives for gender-typed behavior by parents, teachers, peers, and the media. Finally, cultural factors, includ- ing the relative status of women and men in society, may shape children’s gender development. As you will see in this section, there is empirical evidence for the role of each type of influence in certain behaviors. Indeed, it is likely that most aspects of gen- der development result from the complex interaction of all three sets of factors. gender-typed n behaviors associated with a given person’s gender cross-gender-typed n behaviors asso- ciated with the gender other than that of a given person gender typing n the process of gender socialization and development 596 n chApter 15 GENDER DEVELOPMENT Biological Influences Some researchers interested in biological influences on development consider pos- sible ways that gender differences in behavior may have emerged during the course of human evolution. Other biologically oriented researchers focus more directly on identifying hormonal factors and differences in brain functioning as possible influ- ences on gender differences in behavioral development. Evolutionary Approaches As discussed in Chapter 9, evolutionary theory proposes that certain characteris- tics that facilitate survival and the transmission of genes to succeeding generations have been favored over the course of human evolution. Developmental psychol- ogists generally agree that evolution is important for understanding children’s development. However, there are different views regarding the proposal that females and males evolved different behavioral dispositions. Two examples are evo- lutionary psychology theory and biosocial theory. evolutionary psychology theory According to evolutionary psychology theory, certain behavioral tendencies occur because they helped humans survive during the course of evolution. Some evolutionary psychology theorists propose that particu- lar gender differences in behavior reflect evolved personality dispositions. These theorists argue that sex-linked dispositions evolved to increase the chances that women and men would successfully mate and protect their offspring (Bjorklund & Pellegrini, 2002; D. M. Buss, 1999; Geary, 1998; Kenrick, Trost, & Sundie, 2004). As noted in Chapter 9, studies of children’s play behavior show average gen- der differences that have been interpreted as consistent with the evolutionary perspective. For example, more boys than girls tend to engage in physically active, rough-and-tumble, and com- petitive types of play. Many boys devote considerable effort to jockeying with their male peers for domi- nance in groups. Geary (1999) proposed that boys’ play- fighting may represent an “evolved tendency to practice the competencies that were associated with male–male competition during human evolution” (p. 31). A propen- sity to engage in physical aggression is thought to have provided reproductive advantages for males in competi- tion with other males for resources, including access to females (Geary, 1999, 2004). In contrast, girls devote much effort to establishing and maintaining positive social relations, spend time in smaller groups of close female friends, and tend to avoid open con- flict in their interactions. Girls also engage in much more play-parenting, including play with dolls, than boys do. From the evolutionary psy- chology perspective, these behaviors reflect evolved dispositions because maternal care in the form of breast-feeding was required for infants’ survival. In addition, nurturance and other affiliative behaviors may have increased the probability that their offspring would survive long enough to reproduce. Evolutionary psychology theory is a popular approach, but a number of its pro- posals regarding gender differences are controversial. Some biologists and psy- chologists argue that many of evolutionary psychology theory’s claims about sex differences in personality traits cannot be tested (S. J. Gould, 1997; Lickliter & rates of physical aggression with peers tend to be higher for boys than for girls in all cul- tures that have been studied, although the magnitude of the average gender difference varies across cultures. © W O O D Y S T O C K / A LA M Y T H E O R E T I C A L A P P R O A C H E S T O G E N D E R D E V E L O P M E N T n 597 Honeycutt, 2003; W. Wood & Eagly, 2002). These critics also argue that some of the theory’s explanations are based on circular reasoning: If an average sex differ- ence in behavior occurs—such as women being more likely than men to express nurturance—it is seen as having helped humans survive during the course of evolu- tion, and it is considered adaptive during evolution because the average gender dif- ference exists today. Such an argument merely asserts its premise as its conclusion and therefore is a difficult argument to test! Perhaps the clearest way to establish evidence of evolutionary influences would be to link sex differences in particular behaviors to genetic variations on sex chromosomes. We review work in this area later in the chapter. Keep in mind that evolutionary psychology theory is not synonymous with all evolutionary approaches. An alternative evolutionary view emphasizes human evolution as maximizing our capacity for behavioral flexibility as an adaptation to environmental variability (S. J. Gould, 1997; Lickliter & Honeycutt, 2003). This view also points out that, because of their focus on biological constraints in gender development, some versions of evolutionary psychology theory can be construed as a rationalization for the status quo in traditional gender roles (Angier, 1999; S. J. Gould, 1997). As reviewed next, biosocial theory is an evo- lutionary approach that places more emphasis on the potential for behavioral flexibility while also acknowledging the impact of evolution on sex differences in physical characteristics. Biosocial theory Wood and Eagly (2002) have offered biosocial theory as an alter- native evolutionary approach to understanding gender development. Biosocial the- ory focuses on the evolution of physical differences between the sexes and proposes that these differences have behavioral and social consequences. For much of human history, the most important physical differences have been (1) men’s greater average size, strength, and foot speed and (2) women’s childbearing and nursing capacities. Men’s physical abilities gave them an advantage in activities such as hunting and combat and, in turn, tended to confer status and social dominance in the society. In contrast, bearing and nursing children limited women’s mobility and involvement in many forms of economic subsistence such as hunting. However, according to biosocial theory, biology does not necessarily determine destiny. Nowadays in technological societies, men’s strength and other physical qualities are not relevant for most means of subsistence. For example, strength is irrelevant to succeeding as a manager, a lawyer, a physician, or an engineer. All these high-status occupations are now performed by women as well as by men (although gender equality is not fully realized in any of these occupations). Also, reproductive control and day care provide women greater flexibility to maintain their involve- ment in the labor force. Thus, according to biosocial theory, both physical sex dif- ferences and social ecology shape the different gender roles assigned to men and women—as well as the socialization of boys and girls. As we have seen, some claims associated with evolutionary psychology theory are criticized for emphasizing biological determinants of gender differences. How- ever, evolutionary psychologists take issue with biosocial theory, asserting that the body and the mind evolved together and that biosocial theory addresses only the body’s impact on gender development (Archer & Lloyd, 2002; Luxen, 2007). In sum, evolutionary psychology theory and biosocial theory both acknowledge the importance of the physical differences between women and men. But evolutionary psychology theorists additionally argue for the impact of sex differences in evolved behavioral dispositions. 598 n chApter 15 GENDER DEVELOPMENT Neuroscience Approaches Researchers who take a neuroscience approach focus on testing whether and how hormones and brain functioning relate to variations in gender development (Berenbaum, 1998; Hines, 2004). Some neuroscience researchers also frame their work in terms of an evolutionary psychology perspective (Geary, 1998, 2004). hormones and brain functioning In the study of gender development, much attention has been paid to the possible effects of androgens, a class of steroid hor- mones that includes testosterone (Box 15.1). As discussed in Chapter 2, during normal prenatal development, the presence of androgens leads to the formation of male genitalia in genetic males; in their absence, female genitalia are formed in genetic females. Androgens can also have organizing or activating influences on the nervous system. Organizing influences occur when certain sex-linked hormones affect brain differentiation and organization during prenatal development or at puberty. For example, sex-related differences in prenatal androgens may influence the or- ganization and functioning of the nervous system; in turn, this may be related to later average gender differences in certain play preferences (see Berenbaum, 1998). Activating influences occur when fluctuations in sex-linked hormone levels in- fluence the contemporaneous activation of certain brain and behavioral responses (Collaer & Hines, 1995). For example, as discussed later, the body increases an- drogen production in response to perceived threats, with possible implications for gender differences in aggression. Brain structure and functioning Male and female brains show some small dif- ferences in physical structure (Hines, 2004). One such difference is in the cor- pus callosum (the connection between the brain’s two hemispheres), which tends to be larger and to include more dense nerve bundles in women than in men androgens n class of steroid hormones that normally occur at higher levels in males than in females and that affect physical development and functioning from the prenatal period onward organizing influences n potential result of certain sex-linked hormones affecting brain differentiation and organi- zation during prenatal development or at puberty activating influences n potential result of certain fluctuations in sex-linked hor- mone levels affecting the contempora- neous activation of the nervous system and corresponding behavioral responses gender dysphoria disorder n psychi- atric diagnosis included in the DSM-5 to refer to children who identify with the other gender and indicate cross-gender- typed interests Most children’s gender identification is con- sistent with their observable genitalia and gender socialization. That is, children’s view of themselves as “a girl” or “a boy” is consistent with their genetic sex and the gender- role expectations others hold for them. However, in some rare cases, children believe that their gender is not the one that others take it to be. Studies of such cases suggest that, once established, the child’s initial gender identification is often imper- vious to parental attempts to socialize the child as a member of what the child per- ceives as the “wrong” gender. The potential power of children’s pref- erences over gender socialization occurs when children identify with the other gen- der. Some boys indicate a preference to identify as a girl, and some girls express a preference to identify as a boy. These chil- dren usually favor cross-gender-typed play activities and clothing and dislike gender- typed activities (Zucker & Bradley, 1995). Such discrepant gender identity usually appears very early in development, mostly occurs in boys, and can be difficult to alter even with parental socialization efforts. These cases suggest that gender identifica- tion has a biological component. The bio- logical perspective points to the prenatal impact of sex hormones on the developing fetal brain. Such biological influences seem to contribute to gender identity as well as to behavioral gender differences. There is currently a debate in psychology over whether children with discrepant gen- der identities should be classified as hav- ing a psychiatric disorder. In the DSM-5, the latest version of the American Psychi- atric Association’s (2013) compendium, these children receive the diagnosis of gender dysphoria disorder (formerly “gender identity disorder”). Some clinicians contend that children with discrepant gender iden- tity are distressed and require care (Zucker, 2006). Other psychologists argue that applying a disorder label to children with cross-gender-typed interests merely reflects BOX 15.1: a closer look GENDER IDENTITY: MORE THAN SOCIALIZATION? T H E O R E T I C A L A P P R O A C H E S T O G E N D E R D E V E L O P M E N T n 599 (Driesen & Raz, 1995). When engaged in cognitive tasks (e.g., deciding whether words rhyme or navigating a maze), the male brain tends to show activations in one hemisphere or the other, whereas the female brain tends to show activations in both hemispheres (B. A. Shaywitz et al., 1995). However, this particular dif- ference does not appear to result in any advantage to cognitive performance (D. F. Halpern, 2012). One limitation of research documenting sex differences in brain structure is that it is mostly based on brain-imaging studies performed on adults. Given the con- tinual interaction of genes and experience during brain development, it is unclear to what extent any differences in the brain’s structure or functioning seen in adults are due to genetic or environmental influences. It is also unclear to what extent these small differences in brain structure determine any gender differences in ability and behavior (D. F. Halpern, 2012). Cognitive and Motivational Influences Cognitive theories of gender development emphasize the ways that children learn gender-typed attitudes and behaviors through observation, inference, and practice. According to these explanations, children form expectations about gender that guide their behavior. Cognitive theories stress children’s active self- socialization: individuals use their beliefs, expectations, and preferences to guide how they per- ceive the world and the actions that they choose. Self-socialization occurs in gender development when children seek to behave in accord with their gender identity as a girl or a boy. However, cognitive theories also emphasize the role of the environment—the different role models, opportunities, and incentives that girls and boys might experience. We next discuss four pertinent cognitive theories of gender development: cognitive developmental theory, gender schema theory, social identity theory, and social cognitive theory. transgender n a person whose gender identity does not match the person’s genetic sex; includes individuals who identify either with the other sex, with both sexes, or with neither sex. congenital adrenal hyperplasia (CAH) n condition during prenatal devel- opment in which the adrenal glands produce high levels of androgens; some- times associated with masculinization of external genitalia in genetic females; and sometimes associated with higher rates of masculine-stereotyped play in genetic females androgen insensitivity syndrome (AIS) n condition during prenatal devel- opment in which androgen receptors mal- function in genetic males, impeding the formation of male external genitalia; in these cases, the child may be born with female external genitalia. self-socialization n active process during development whereby children’s cognitions lead them to perceive the world and to act in accord with their expectations and beliefs societal pressures for gender-role conformity (Bartlett, Vasey, & Bukowski, 2000). Along these lines, some people argue for a broader notion of gender that goes beyond thinking only of the two categories of “female” or “male.” This includes accep- tance of transgender youth and adults, indi- viduals whose gender identity does not match their genetic sex. Some transgendered indi- viduals prefer to identify with the other gen- der, with both genders, or with neither gender. Another group of individuals who seek to broaden the gender spectrum include those born with intersex conditions (Preves, 2003). Intersex conditions are due to reces- sive genes that cause, in rare instances, a person of one genetic sex to develop genital characteristics typical of the other genetic sex. (Intersex individuals may also consider themselves transgender.) Two such intersex conditions are congenital adrenal hyperpla- sia and androgen insensitivity syndrome. High levels of androgens produced during the prenatal development of genetic females can lead to congenital adrenal hyperplasia (CAH), a condition that involves the formation of male (or partly masculinized) genitalia. Researchers have studied girls with CAH to infer the possible influence of androgens on gender development. They have found that, compared with other girls, those with CAH are more likely to choose physically active forms of play, such as rough-and-tumble play, and to avoid sedentary forms of play, such as playing with dolls (Berenbaum & Hines, 1992; Nordenström et al., 2002). This evi- dence has been used to support the idea that prenatal androgens may partly contribute to boys’ and girls’ gender identities and to gen- der-typed play preferences. In addition, this kind of evidence is sometimes used to sup- port evolutionary accounts of gender develop- ment (G. M. Alexander, 2003). In contrast, androgen insensitivity syndrome (AIS), a rare syndrome in genetic males, causes androgen receptors to malfunction. In these cases, genetic males may be born with female external genitalia. 600 n chApter 15 GENDER DEVELOPMENT Cognitive Developmental Theory Lawrence Kohlberg’s (1966) cognitive developmental theory of gender-role development reflects a Piagetian framework (reviewed in Chapter 4). Kohlberg proposed that children actively construct knowledge in the same way, in the Piagetian view, that they construct knowledge about the physical world. Kohlberg maintained that children’s understanding of gender involves a three-stage process that occurs between approximately 2 to 6 years of age. First, by around 30 months of age, young children acquire a gender identity: they cat- egorize themselves either as a girl or a boy (Fagot & Leinbach, 1989). However, they do not yet realize that gender is permanent. For example, young children may believe that a girl could grow up to be a father (Slaby & Frey, 1975). The second stage, which begins at around 3 or 4 years of age, is gender stability: children come to realize that gender remains the same over time (“I’m a girl, and I’ll always be a girl”). However, they are still not clear that gender is independent of superficial appearance and think that a boy who has put on a dress and now looks like a girl has become a girl. The basic understanding of gender is completed in the third stage, around 6 years of age, when children achieve gender constancy, the understanding that gender is invariant across situations (“I’m a girl, and nothing I do will change that”). Kohlberg noted that this is the same age at which children begin to suc- ceed on Piagetian conservation problems and argued that both achievements reflect the same stage of thinking. Kohlberg maintained that children’s under- standing that gender remains constant even when superficial changes occur is similar to their understanding that the amount of a substance is conserved even when its appearance is altered (a ball of clay that has been mashed flat is still the same amount of clay; a girl who gets her hair cut short and starts wearing baseball shirts instead of dresses is still a girl). According to Kohlberg, once gen- der constancy is attained, children begin to seek out and attend to same-gender models to learn how to behave (“Since I’m a girl, I should like to do girl things, so I need to find out what those are”). Subsequent research has supported the idea that children’s understand- ing of gender develops in the sequence Kohlberg hypothesized and that the attainment of gender constancy occurs at more or less the same age as suc- cess on conservation problems (e.g., D. E. Marcus & Overton, 1978; Munroe, Shimmin, & Munroe, 1984). Studies also indicate that acquiring gender constancy increases the likelihood of many gender- typed behaviors (C. L. Martin et al., 2002). Gender schema theory, reviewed next, also addresses ways that attaining a concept of gender can affect chil- dren’s gender development. Gender Schema Theory Martin and Halverson (1981) proposed gen- der schema theory as an alternative to Kohlberg’s explanation of children’s gender development (also see Bem, 1981). In contrast to Kohlberg’s view that gender-typed interests emerge after gender constancy is achieved, gender schema theory holds that the motivation to enact gender-typed behavior begins as As predicted by cognitive theories, children learn a great deal about gender roles by observing other people. television, movies, and video games provide many examples of gender stereotypes for both sexes. JU LI A C U M E S / T H E I M A G E W O R K S gender identity n awareness of oneself as a boy or a girl gender stability n awareness that gender remains the same over time gender constancy n realization that gender is invariant despite superficial changes in a person’s appearance or behavior T H E O R E T I C A L A P P R O A C H E S T O G E N D E R D E V E L O P M E N T n 601 soon as children can label other people’s and their own gender—in other words, when they are toddlers. Accordingly, children’s understanding of gender develops through their con- struction of gender schemas, mental representations incorporating everything the child knows about gender. Gender schemas include memories of one’s own experi- ences with males and females, gender stereotypes transmitted directly by adults and peers (“boys don’t cry,” “girls play with dolls”), and messages conveyed indirectly through the media. Children use an ingroup/outgroup gender schema to classify other people as being either “the same as me” or not. The motivation for cognitive consistency leads them to prefer, pay attention to, and remember more about others of their own gender. As a consequence, an own-gender schema is formed, consisting of detailed knowledge about how to do things that are consistent with one’s own gender. Simply learning that an unfamiliar object is “for my gender” makes chil- dren like it more. Figure 15.1 illustrates how this process leads children to acquire greater knowledge and expertise with gender-consistent entities. To test the impact of gender schemas on children’s information processing, 4- to 9-year-olds were given three boxes. Each contained unfamiliar, gender-neutral objects, and each was separately labeled as “boys,” “girls,” or “boys and girls/girls and boys.” The children spent more time exploring objects in boxes labeled for their own gender (or for both genders) than objects in the box labeled only for the other gender. One week later, not surprisingly, they remembered more details about the objects that they had explored than about the ones that they had spent less time with (Bradbard et al., 1986). Children regularly look to their peers to infer gender-appropriate behavior. In an observational study conducted in a preschool classroom, boys were influenced by the number and the proportion of same-gender children who were playing with a set of toys: they approached toys that were being played with primarily by boys and shunned those that seemed popular mainly with girls (Shell & Eisenberg, 1990). Gender schemas are also responsible for biased processing and remembering of information about gender. Consistent with the research described above, children tend to remember more about what they observe from same-gender than from cross- gender role models (Signorella, Bigler, & Liben, 1997; Stangor & McMillan, 1992). They are also more likely to accurately encode and remember information about story characters that behave in gender-consistent ways and to forget or distort information Girl Truck Doll For whom? For whom? For boys Not for me For me Therefore Avoid; forget Own-sex schema Approach; gather information; remember information So So For girls Gender identity (I’m a girl) Therefore FIGURE 15.1 Gender schema theory According to gender schema theory, chil- dren classify new objects and activities as “for boys” or “for girls.” they tend to inves- tigate objects and activities that are relevant to their gender and to ignore those that are associated with the other gender. gender schemas n organized mental representations (concepts, beliefs, mem- ories) about gender, including gender stereotypes 602 n chApter 15 GENDER DEVELOPMENT that is gender-inconsistent (Liben & Signorella, 1993; C. L. Martin & Halverson, 1983). For example, children who heard a story that featured a girl sawing wood often remembered it later as a story about a boy sawing wood. Similarly, children who saw pictures that showed a boy playing with a doll and a girl playing with a truck tended to misremember the gender of the children performing these respective actions (C. L. Martin & Halverson, 1983). This tendency to retain information that is schema-consistent and to ignore or distort schema-inconsistent information helps to perpetuate gender stereotypes that have little or no basis in reality. Liben and Bigler (2002) have added another component to gender schema theory. They proposed that children use two kinds of filters when processing in- formation about the world. One is a gender schema filter (“Is this information relevant for my gender?”) and the other is an interest filter (“Is this information interesting?”). When encountering a new toy, for example, children may decide that it is something for girls or for boys and explore or ignore the toy on the basis of their gender schema filter. This is the same process emphasized in Martin and Halverson’s gender schema theory. However, Liben and Bigler noted that children sometimes find a new toy attractive without initially evaluating its appropriateness for their gender. In these instances, they use their interest filter to evaluate informa- tion. Furthermore, children sometimes use their interest filter to modify their gender schemas (“If I like this toy, it must be something that is okay for my gender”). Liben and Bigler’s modification to gender schema theory helps to account for findings indicating that children are often inconsistent in their gender-typed interests (for example, they are often more traditional in some areas than others). It also allows for the fact that some children actively pursue certain cross-gender-typed activities simply because they enjoy them. Although gender schemas are resistant to change, the contents of children’s gender schemas can be modified through explicit instruction. Such an approach was dem- onstrated by Bigler and Liben, who created a cognitive intervention program in which elementary school children learned that a person’s interests and abilities (but not gender) are important for the kind of job that the person could have (Bigler & Liben, 1990; Liben & Bigler, 1987). (The chil- dren were encouraged to see, for example, that if Mary was strong and liked to build things, a good job for her would be to work as a carpenter.) Children who participated in this week-long program showed decreased gender stereotyping and also had better memory for gender-inconsistent stimuli (such as a picture of a girl holding a hammer). However, a limitation of interventions aimed at reducing gender stereo- typing is the fact that their impact typically fades once the intervention ends (Bigler, 1999). That is, children gradually revert back to their old gender stereotypes. Given the perva- siveness of gender stereotyping in children’s everyday lives, cognitive interventions need to be sustained to have a longer-lasting effect. Social Identity Theory Developmental psychologists have highlighted the importance of gender as a social identity in children’s development (e.g., Bigler & Liben, 2007; J. R. Harris, 1995; Leaper, 2000; Nesdale, 2007; Powlishta, 1995). Indeed, gender may be the gender schema filter n initial evalu- ation of information as relevant for one’s own gender interest filter n initial evaluation of information as being personally interesting children’s stereotyped beliefs about gender can be changed through cognitive inter- vention programs. children who learned that a person’s interests and abilities were important for the kind of job the person could have showed significant reductions in gender stereotyping. B O N N IE K A M IN / P H O T O E D IT T H E O R E T I C A L A P P R O A C H E S T O G E N D E R D E V E L O P M E N T n 603 most central social identity in children’s lives (Bem, 1993). Children’s commitment to gender as a social identity is most readily apparent through their primary affili- ation with same-gender peers (Leaper, 1994; Maccoby, 1998). Henri Tajfel and John Turner’s (1979) social identity theory addresses the influence of group membership on people’s self-concepts and behavior with oth- ers. Two influential processes that occur when a person commits to an ingroup are ingroup bias and ingroup assimilation. Ingroup bias refers to the tendency to eval- uate individuals and characteristics associated with the ingroup as superior to those associated with the outgroup. For example, Kimberly Powlishta (1995) observed that children showed same-gender favoritism when rating peers on like- ability and favorable traits. Ingroup bias is related to the process of ingroup assimilation, whereby individuals are socialized to conform to the group’s norms. That is, peers expect ingroup members to demonstrate the characteristics that define the ingroup. Thus, they anticipate ingroup approval for preferring same-gender peers and same-gender-typed activities, as well as for avoiding other-gender peers and cross- gender-typed activities (R. Banerjee & Lintern, 2000; C. L. Martin et al., 1999). As a result, children tend to become more gender-typed in their preferences as they assimilate into their same-gender peer groups (C. L. Martin & Fabes, 2001). A corollary of social identity theory is that the characteristics associated with a high-status group are typically valued more than those of a low-status group. In male-dominated societies, masculine-stereotyped attributes such as assertiveness and competition tend to be valued more highly than feminine-stereotyped attri- butes such as affiliation and nurturance (Hofstede, 2000). Related to this pattern is the tendency of cross-gender-typed behavior to be more common among girls than among boys. Indeed, masculine-stereotyped behavior in a girl can sometimes enhance her status, whereas feminine-stereotyped behavior in a boy typically tar- nishes his status (see Leaper, 1994). Social identity theory helps to explain why gender-typing pressures tend to be more rigid for boys than for girls (Leaper, 2000). Members of high-status groups, for example, are usually more invested in maintaining group boundaries than are members of low-status groups. In most societies, males are accorded greater sta- tus and power than are females. Consistent with social identity theory, boys are more likely than girls to initiate and maintain role and group boundaries (Fagot, 1977; Sroufe et al., 1993). Boys are also more likely to endorse gender stereotypes (Rowley et al., 2007) and to hold sexist attitudes (C. S. Brown & Bigler, 2004). Social Cognitive Theory Kay Bussey and Albert Bandura (1999) proposed a theory of gender development based on Bandura’s (1986, 1997) social cognitive theory (see pages 352–354). The theory depicts a triadic model of reciprocal causation among personal factors, envi- ronmental factors, and behavior patterns. Personal factors include cognitive, moti- vational, and biological processes. Although the theory acknowledges the potential influence of biological factors, it primarily addresses cognition and motivation. Among its key features are sociocognitive modes of influence, observational learn- ing processes, and self-regulatory processes. According to social cognitive theory, learning occurs through tuition, enactive experience, and observation. Tuition, which refers to direct teaching, occurs during gen- der socialization—for example, when a father shows his son how to throw a baseball, or a mother teaches her daughter how to change a baby’s diaper. Enactive experience occurs when children learn to guide their behavior by taking into account the ingroup bias n tendency to eval- uate individuals and characteristics of the ingroup as superior to those of the outgroup ingroup assimilation n process whereby individuals are socialized to con- form to the group’s norms, demonstrating the characteristics that define the ingroup tuition n learning through direct teaching 604 n chApter 15 GENDER DEVELOPMENT reactions their past behavior has evoked in others. For instance, girls and boys usually get positive reactions for behaviors that are gender-stereotypical and negative reac- tions for behaviors that are counter-stereotypical (Fagot, 1977), and they tend to use this feedback to regulate their behavior in relevant situations. Finally, observational learning—the most common form of learning—occurs through seeing and encoding the consequences other people experience as a result of their actions. Thus, children learn a great deal about gender simply through observing the behavior of their par- ents, siblings, teachers, and peers. (Some examples of gender socialization in the fam- ily are described in Box 15.2.) Children also learn about gender roles through media such as television, films, and computer and video games (see Box 15.3). Parents convey messages about gender in many ways. One is in the division of house- hold labor. Although many American parents share responsibilities, most mothers and fathers in two-parent families tend to model traditional roles. Mothers are more likely to be primarily responsible for basic child- care and cleaning; fathers are more likely to be responsible for household maintenance. Analogous patterns tend to hold in parents’ assignment of household chores to daugh- ters and sons. In general, boys are more likely than girls to take out the trash, help wash the car, mow the lawn, and perform other tasks outside the home. Girls are more likely than boys to help care for younger sib- lings and to perform other tasks inside the home (Grusec, Goodnow, & Cohen, 1996). This gender-based role modeling and assignment of chores implies a natural divi- sion of labor and may influence boys’ and girls’ emerging interests and preferences (Leaper, 2002). In conversations between parents and children, parents often convey relatively subtle messages about gender through the use of gender-essentialist statements phrased in the timeless present tense, such as “Boys play football” and “Girls take ballet.” This linguistic form implies that the activities and implied characteristics in question are and always will be generally true of the group as a whole. In contrast, nonessentialist state- ments such as “Those girls are taking bal- let lessons” carry no such implications. In a study of the comments that mothers made as they read stories to their toddlers or preschool children, nearly all (96%) used gender-essentialist language when referring to the gender of the story characters and activities (S. A. Gelman, Taylor, & Nguyen, 2004). They also used gender to distinguish the characters’ activities (“Does that look more like a boy job or a girl job?”). Such language use may convey the idea that gen- der is an important distinction and that gen- der-related characteristics are universal and stable (Leaper & Bigler, 2004). Another difference in how parents talk to boys and to girls was found in a study that used naturalistic observation to document parent–child conversations in a science museum. While using interactive exhibits, parents were three times more likely to offer explanations to boys about what they were observing than they were to girls (Crowley et al., 2001). In a different study, researchers observed that when demonstrating a physics task to their school-aged children, fathers used more instructional talk (explanations, technical vocabulary) with sons than with daughters (Tenenbaum & Leaper, 2003). Presumably, both sets of findings occurred because adults assumed that boys are more scientifically inclined than are girls. BOX 15.2: a closer look GENDER TYPING AT HOME In most U.S. households, children’s chores are assigned in ways that differ by gender: girls are responsible for tasks performed inside the home, whereas boys are more often assigned chores that involve machinery and that are performed outside the home. C O M S T O C K / T H IN K S T O C K enactive experience n learning to take into account the reactions one’s past behavior has evoked in others observational learning n learning through watching other people and the consequences others experience as a result of their actions gender-essentialist statements n remarks about males’ and females’ activi- ties and characteristics phrased in lan- guage that implies they are inherent to the group as a whole T H E O R E T I C A L A P P R O A C H E S T O G E N D E R D E V E L O P M E N T n 605 computer and online games are beginning to displace television as the primary source of chil- dren’s media entertainment. Unfortunately, like television programming, many computer games portray the sexes in highly stereotyped ways. R E U T E R S / B E A W IH A R TA BOX 15.3: applications WHERE ARE SPONGESALLY SQUAREPANTS AND CURIOUS JANE? Before reading further, take a moment to list your five favorite television programs. Now count the number of major characters in them who are female and male. Which characters are highly active and/or have positions of power on the show? How would you characterize the general nature of your programs—action-packed adventures, romantic comedies, sports shows, reality series? What would be different if you made a list of the programs you liked best as a child? We would be willing to bet that your list of major characters includes more males than females, probably by a substantial degree. We also suspect that more male than female readers would list action and sports as favorite programs, whereas more female than male readers would have romantic shows on their lists. The imbalance in female and male characters in your current favorite shows is probably not much different from what you would find in the shows you watched in your youth. The reason we feel such confidence in our predictions is that differences in the gender representation of characters on TV have been well documented, are very large, and have changed relatively little over the past three decades (Huston & Wright, 1998; Leaper et al., 2002; Signorielli, 2001; T. L. Thompson & Zerbinos, 1995). One study of children’s TV cartoons, however, did indicate that female and male characters were more equal in number and less gender-stereotyped in their portrayals on public television than on commercial television (Leaper et al., 2002). The differential treatment of the sexes in the media is not limited to numbers. Por- trayals of males and females tend to be highly stereotypical in terms of appear- ance, personal characteristics, occupa- tions, and the nature of the characters’ roles. On average, male characters tend to be older and in more powerful roles; females tend to be young, attractive, and provoca- tively dressed (Diekman & Murnen, 2004; Gooden & Gooden, 2001; Leaper et al., 2002; Signorielli, 2012; T. L. Thompson & Zerbinos, 1995). Do the large differences in both the number and nature of the portrayals of the sexes on TV matter? Keep in mind that for U.S. children, weekly TV consumption (in- cluding DVR, DVD, and the like) is over 32 hours for those between ages 2 and 5 and over 28 hours for those between ages 6 and 11 (The Nielsen Company, 2009). In addition, for most young children, television is a major source of information about the world at large (Gerbner et al., 2002). From a gender-typing perspective, the fact that children have so much exposure to highly stereotyped gender models matters a great deal. For example, children who watch a lot of TV have more highly stereotypic beliefs about males and females and prefer gender- typed activities to a greater extent than do children who are less avid viewers (Oppliger, 2007). Furthermore, several experimental studies have established a causal relation- ship between TV viewing and gender stereo- typing (Oppliger, 2007). For example, when children are randomly assigned to watch TV shows with either gender- stereotyped or neutral content, they are more likely to endorse gender stereotypes themselves after watching gender-stereotyped programs. Children are, of course, exposed to media other than television, but simi- lar gender disparities have been docu- mented in them as well. For example, children’s books still contain far more male than female characters, and characters of both sexes are often portrayed in gender- stereotypic ways. Males tend to be depicted as active and effective in the world at large, whereas females are frequently passive and prone to problems that require the help of males to solve (DeWitt, Cready, & Seward, 2013; Diekman & Murnen, 2004; Gooden & Gooden, 2001; Hamilton et al., 2006). Thus, although it is now possible to find more counter- stereotypical role models in children’s media (e.g., Hermione in the Harry Potter series), most female and male characters con- tinue to be gender-stereotyped. Computer and online games are beginning to displace televi- sion as the primary source of children’s media entertainment. Unfortunately, like television programming, many computer games portray the sexes in highly stereotyped ways. 606 n chApter 15 GENDER DEVELOPMENT Observational learning of gender-role information involves four key processes: attention, memory, production, and motivation. To learn new information, it must, of course, be attended to (noticed) and then stored in memory. As we have noted, children often notice information that is consistent with their existing gender stereotypes. (This is the main premise of gender schema theory.) Next, children need to practice the behavior (production) that they have observed (assuming that the behavior is within their capabilities). Finally, children’s motivation to repeat a gender- typed behavior will depend on the incentives or disincentives they experi- ence relative to the behavior. These sanctions can be experienced either directly (as when a parent praises a daughter for helping to prepare dinner) or indirectly (as when a boy observes another boy getting teased for playing with a doll). Over time, external sanctions are usually internalized as personal standards and become self- sanctions that motivate behavior. According to the social cognitive theory, children monitor their behavior and evaluate how well it matches personal standards. After making this evaluation, children may feel pride or shame, depending on whether they meet their standards. When individuals experience positive self-reactions for their behavior, they gain the sense of personal agency referred to as self-efficacy (see pages 354–355). Self- efficacy can develop gradually through practice (as when a son regularly plays catch with his father), through social modeling (as when a girl observes a female friend do well in math and thinks that maybe she could do well herself ), and by social persuasion (as when a coach gives a pep talk to push the boys’ performances on the baseball field). Researchers consistently find a strong relation between feelings of self-efficacy and motivation. For example, self-efficacy in math predicts girls’ as well as boys’ likelihood of taking advanced math courses (Stevens et al., 2007). Cultural Influences The theoretical approaches that we have discussed so far emphasize biological and cognitive-motivational processes involved in gender development. Complementing these approaches are theories that address the larger cultural and social-structural factors that can shape gender development. Two relevant theories that reflect this approach are the bioecological model and social role theory. Both emphasize how cultural practices mirror and perpetuate the gender divisions that are prevalent in a society. Bioecological Model As described in Chapter 9, Urie Bronfenbrenner’s bioecological model of human development differentiates among interconnected systems, from the micro- system (the immediate environment) to the macrosystem (the culture), that in- fluence children’s development over time (see Figure 9.4) (Bronfenbrenner, 1979; Bronfenbrenner & Morris, 1998). A fundamental feature of the macrosystem is its opportunity structure, that is, the economic resources it offers and people’s understanding of those resources (Ogbu, 1981). Opportunities for members of a cultural community can vary depending on gender, income, and other factors and are reflected by the dominant adult roles within that cultural community. According to the bioecological approach, child socialization practices in particu- lar microsystems serve to prepare children for these adult roles. Thus, traditional gender-typing practices perpetuate as well as reflect the existing opportunity struc- tures for women and men in a particular community at a particular time in history opportunity structure n the economic and social resources offered by the mac- rosystem in the bioecological model, and people’s understanding of those resources M I L E S T O N E S I N G E N D E R D E V E L O P M E N T n 607 (Whiting & Edwards, 1988). To the extent that children’s development is largely an adaptation to their existing opportunities, changes in children’s macrosystems and microsystems can lead to greater gender equality (see Leaper, 2000). For exam- ple, increased academic and professional opportunities for girls in the United States have led to a dramatic narrowing of the gender gap in math and science within the past 30 years (D. F. Halpern et al., 2007). Social Role Theory A fundamental premise of Alice Eagly’s social role theory is that different expecta- tions for each gender stem from the division of labor between men and women in a given society (Eagly, 1987; Eagly, Wood, & Diekman, 2000). To the extent that family and occupational roles are allocated on the basis of gender, different behaviors (roles) are expected of women and men (as well as of girls and boys). An obvious example, al- luded to above, was the traditional exclusion of women from many occupations in the United States and similar societies. Women were underrepresented in politics, busi- ness, science, technology, and various other fields. In turn, girls were not expected to develop interests and skills that lead toward professions in those fields. Thus, some- what similar to the bioecological model, social role theory highlights ways that insti- tutionalized roles impose both opportunities and constraints on people’s behavior and beliefs in the home, schools, the labor force, and political institutions. review: To varying degrees, biological, cognitive-motivational, and cultural factors relate to different aspects of gender development. In their theories and work, researchers tend to focus on one set of factors—although they usually acknowledge that other influences are also important. In trying to explain gender differences in behavior, some researchers focus on biological factors. Those who adopt an evolutionary perspective argue that gender differences in behav- ior emerged over the course of human evolution because they offered reproductive advantages to males and females. Disagreement exists, however, regarding the degree that evolution led to different behavioral predispositions for females and males. Other biological approaches focus on measureable physiological processes that may be related to variations in develop- ment, such as sex-related hormonal influences and sex differences in brain functioning. Researchers who focus on cognitive-motivational processes emphasize how children’s gender-related beliefs, expectations, and preferences guide their behavior. Once children begin to identify with members of their own gender, they are typically motivated to acquire interests, values, and behavior in accord with their social identity as girls or boys. Self- socialization plays a prominent role in cognitive theories because it is primarily children themselves who initiate and enforce many forms of gender-typed behavior. Cross-cultural comparisons and historical change within the United States and other countries underscore ways that gender roles are tied to culture. Societal values and cultural practices can limit or enhance the role models and opportunities that girls and boys experi- ence during development. Milestones in Gender Development Developmental psychologists have identified general patterns that tend to occur over the course of children’s gender development. As reviewed next, gender- related changes are evident in children’s physical, cognitive, and social develop- ment. Recall that these changes begin during prenatal development, when sexual differentiation occurs. 608 n chApter 15 GENDER DEVELOPMENT Infancy and Toddlerhood During their first year, infants’ perceptual abilities allow them to figure out that there are two groups of people in the world: females and males. As we saw in Chapter 5, much research indicates that infants can detect complex regulari- ties in perceptual information. Clothing, hairstyle, height, body shape, motion patterns, vocal pitch, and activities all tend to vary with gender, and these dif- ferences provide infants with gender cues. For example, habituation studies of infant perception and categorization indicate that by about 6 to 9 months of age, infants can distinguish males and females, usually on the basis of hairstyle (Intons-Peterson, 1988). Infants can also distinguish male and female voices and make intermodal matches on the basis of gender (C. L. Martin et al., 2002). For instance, they expect a female voice to go with a female face rather than with a male face. Although we cannot conclude that infants understand anything about what it means to be female or male, it does appear that older infants recognize the physical difference between females and males by using multiple perceptual cues. Shortly after entering toddlerhood, children begin exhibiting distinct pat- terns of gender development. By the latter half of their second year, children have begun to form gender-related expectations about the kinds of objects and activities typically associated with males and females. For example, 18-month-olds looked longer at a doll than at a toy car after viewing a series of female faces, and looked longer at a toy car than at a doll after habituating to male faces (Serbin et al., 2001). Another study with 24-month-olds found that counter-stereotyp- ical matches of gender and action (e.g., a man putting on lipstick) led to longer looking times; it appeared that the children were surprised by the action’s gender inconsistency (Poulin-Dubois et al., 2002). The clearest evidence that children have acquired the concept of gender occurs around 2½ years of age, when they begin to label other people’s genders. For example, researchers might assess this ability by asking children to put pic- tures of children into “boys” and “girls” piles. Toddlers can also make simple gender matches, such as choosing a toy train over a doll when asked to point to the “boy’s toy” (A. Campbell, Shirley, & Caygill, 2002). Children typically begin to show understanding of their own gender identity within a few months after labeling other people’s gender. By age 3, most children use gender terms such as “boy” and “girl” in their speech and correctly refer to themselves as a boy or girl (Fenson et al., 1994). Preschool Years During the preschool years, children quickly learn gender stereotypes—the activities, traits, and roles as- sociated with each gender. By around 3 years of age, most children begin to attribute certain toys and play activities to each gender. By around 5 years of age, they usually stereotype affiliative characteristics to females and assertive characteristics to males (Best & Thomas, 2004; Biernat, 1981; Liben & Bigler, 2002; Serbin, Powlishta, & Gulko, 1993). During this period, children usually lack gender constancy: they do not understand that gender remains stable across time In the United States, children’s play becomes differentiated by gender during the preschool period, with most girls prefer- ring to play with soft toys and to spend time in the “housekeeping” area, and most boys preferring to play with blocks and transpor- tation toys. M IC H E LL E D . B R ID W E LL / P H O T O E D IT M I L E S T O N E S I N G E N D E R D E V E L O P M E N T n 609 and is consistent across situations. For example, a preschooler might think that a girl becomes a boy if she cuts her hair, or that a boy becomes a girl if he wears a dress. Gender-Typed Behavior Many children begin to demonstrate preferences for some gender-typed toys by around 2 years of age. These preferences become stronger for most children during the preschool years (Cherney & London, 2006; Pomerleau et al., 1990; Rheingold & Cook, 1975). Indeed, during childhood, one of the largest aver- age gender differences is in toy and play preferences. Girls are more likely than boys to favor dolls, toy cooking sets, and dress-up materials. Girls are also more likely to invoke domestic themes (such as playing house) in their fantasy play. In contrast, boys are more likely than girls to prefer cars, trucks, building toys, and sports equipment. Boys also are more likely than girls to engage in rough-and- tumble play and to enact action-and-adventure themes (such as playing super- heroes) in their fantasy play. The preschool period is also when gender segregation emerges, as children start to prefer playing with same-gender peers and to avoid other-gender peers (Leaper, 1994; Maccoby, 1998). Gender segregation increases steadily between around 3 and 6 years of age, then remains stable throughout childhood (Figure 15.2). Children’s preference for same-gender peers is seen across different cultures; however, there are some cultural variations in the degree that children play exclu- sively with their own gender (Whiting & Edwards, 1988). Gender-segregated peer groups are a laboratory for children to learn what it means to be a girl or a boy. Peers are both role models and enforcers of gender- typed behavior. Martin and Fabes (2001) identified what they termed a “social dos- age effect” of belonging to same-gender peer groups during early childhood. The amount of time that preschool or kinder- garten children spent with same- gender peers predicted subsequent changes in gender- typed behavior over 6 months. For example, boys who spent more time playing with same-gender peers showed increases over time in aggression, rough- and- tumble play, activity level, and gen- der-typed play. Girls who spent more time playing with same-gender peers showed increases in gender-typed play and decreases in aggression and activity level. The reasons for children’s same-gender peer preferences seem to involve a com- bination of temperamental, cognitive, and social forces (Maccoby, 1998). Their relative influences change over time. At first, children appear to prefer same- gender peers because they have more compatible behavioral styles and interests. For instance, girls may avoid boys because boys tend to be rough and unresponsive to girls’ attempts to influence them, and boys may prefer the company of other boys At age 41/2 At age 61/2 70 60 50 40 30 20 10 0 P er ce n t of s oc ia l p la yt im e With same sex In mixed group With other sex FIGURE 15.2 Gender segregation in play this graph reflects the increase in social playtime between preschool and 1st grade that children spent with playmates of their own gender and the decrease in play- time with playmates of the other gender. (Adapted from Maccoby, 1998) During preschool, children begin to avoid peers who violate gender-role norms, and by age 5 to 7 years, they will actively tease peers who cross gender-role boundaries. this is especially true for boys: the one in this photo is likely to experience peer rejec- tion if he continues to play with dolls and other toys strongly stereotyped as appro- priate for girls. B U B B LE S P H O T O LI B R A R Y / A LA M Y gender segregation n children’s ten- dency to associate with same-gender peers and to avoid other-gender peers 610 n chApter 15 GENDER DEVELOPMENT because they share similar activity levels. Around the time that children begin to exhibit a same-gender peer preference, they also are establishing a gender identity and therefore are further drawn to peers who belong to the same ingroup. As they get older, peer pressures may additionally motivate children to favor same-gender peers. Thus, behavioral compatibility may become a less important factor with age. For example, physically active girls may frequently play with boys during early childhood; however, as these girls get older, they tend to affiliate more with girls—even though their activity preferences may be more compatible with those of boys than with those of girls (Pellegrini et al., 2007). Therefore, ingroup identity and conformity pressures may supersede behavioral compatibility as rea- sons for gender segregation as children get older. Middle Childhood By around 7 years of age, children have attained gender constancy, and their ideas about gender are more consolidated. At this point, children often show a bit more flexibility in their gender stereotypes and attitudes than they did in their younger years (P. A. Katz & Ksansnak, 1994; Liben & Bigler, 2002; Serbin, Powlishta, & Gulko, 1993). For example, they may recognize that some boys don’t like playing baseball and that some girls don’t wear dresses. However, most children continue to be highly gender-stereotyped in their views. Around 9 or 10 years of age, children start to show an even clearer understand- ing that gender is a social category. They typically recognize that gender roles are social conventions as opposed to biological outcomes (D. B. Carter & Patterson, 1982; Stoddart & Turiel, 1985). As children come to appreciate the social basis of gender roles, they may recognize that some girls and boys may not want to do things that are typical for their gender. Some children may even argue that, in such cases, other girls and boys should be allowed to follow their personal prefer- ences. For instance, Damon (1977) found that children would say that a boy who liked to play with dolls should be allowed to do so. However, children also rec- ognized that the boy would probably be teased and that they themselves would not want to play with him. That is, children understood the notion of individual variations in gender typing, but they were also aware that violating gender role norms would have social costs. Another development in children’s thinking is realizing that gender discrimi- nation is unfair and noticing when it occurs (C. S. Brown & Bigler, 2005; Killen, 2007). Killen and Stangor (2001) demonstrated this when they told children sto- ries about a child who was excluded from a group because of the child’s gender. Examples included a boy who was kept out of a ballet club and a girl who was kept out of a baseball-cards club. Eight- and 10-year-olds consistently judged it unfair for a child to be excluded from a group solely because of gender. Despite their capacity to see this as wrong, children commonly exclude other children from activities based on their gender (Killen, 2007; Maccoby, 1998). Brown and Bigler (2005) identified various factors that affect whether children recognize gender discrimination. First among them are cognitive prerequisites, such as having an understanding of cultural stereotypes, being able to make so- cial comparisons, and having a moral understanding of fairness and equity. These abilities are typically reached by middle childhood. People’s awareness of sexism can also be influenced by individual factors such as their self-concepts or beliefs. For example, girls with gender-egalitarian beliefs were more likely to recognize sexism (C. S. Brown & Bigler, 2004; Leaper & Brown, 2008). Finally, the specific M I L E S T O N E S I N G E N D E R D E V E L O P M E N T n 611 situation can affect children’s likelihood of noticing discrimination. For instance, children are more likely to notice discrimination directed toward someone else than toward themselves. Also, they are more apt to recognize gender discrimina- tion in someone known to be prejudiced (C. S. Brown & Bigler, 2005). Gender-Typed Behavior In middle childhood, many boys’ and girls’ peer groups establish somewhat different gender-role norms for behavior (A. J. Rose & Rudolph, 2006). For this reason, some researchers have suggested that each gender usually constructs its own “culture” dur- ing childhood (Maccoby, 1998; Maltz & Borker, 1982; Thorne & Luria, 1986). In line with their tendency to value self-assertion over affiliation, boys’ peer groups are more likely to reflect norms of dominance, self- reliance, and hiding vulnerability. Conversely, in line with their greater tendency to value affiliative goals (or a balance of affiliative and assertive goals), girls’ peer groups are more likely to reflect norms of intimacy, collaboration, and emotional sharing (A. J. Rose & Rudolph, 2006). As we have noted, when children violate gender-role norms, their peers often react negatively (Fagot, 1977), including mercilessly teasing someone who has crossed gender “bor- ders.” The following description of an event in an American elementary school clearly illustrates the degree to which children enforce gender segregation on their own: In the lunchroom, when the two second-grade tables were filling, a high-status [popular] boy walked by the inside table, which had a scattering of both boys and girls, and said loudly, “Oooo, too many girls,” as he headed for a seat at the far table. The boys at the inside table picked up their trays and moved, and no other boys sat at the inside table, which the pronouncement had effectively made taboo. (Thorne, 1986, p. 171) Although most children typically favor same-gender peers, in certain con- texts friendly cross-gender contacts regularly occur in North American and other Western cultures (Sroufe et al., 1993; Strough & Covatto, 2002; Thorne, 1993; Thorne & Luria, 1986). At home and in the neighborhood, the choice of play companions is frequently limited. As a result, girls and boys often play coopera- tively with one another. In more public settings, the implicit convention is that girls and boys can be friendly if they can attribute the reason for their cross- gender contact to an external cause. For example, this might occur when a teacher assigns them to work together on a class project or when they are waiting in line together at the cafeteria. However, beyond such exceptions, the risk of peer rejec- tion is high when children violate the convention to avoid cross-gender contact (Sroufe et al., 1993). Overall, gender typing during childhood tends to be more rigid among boys than among girls (Leaper, 1994; Levant, 2005). As noted earlier, boys are more likely to endorse gender stereotypes than are girls, who tend to endorse gender-egalitarian attitudes (C. S. Brown & Bigler, 2004). In addition, girls are less gender-typed in their behavior. Girls are more likely than boys to play with cross-gender-typed toys, During the elementary school years, boys’ and girls’ groups rarely mix. children them- selves enforce gender segregation; this ten- dency does not seem to be due to adult influences. D A V ID R . F R A Z IE R P H O T O LI B R A R Y, I N C . / A LA M Y 612 n chApter 15 GENDER DEVELOPMENT for example. Also, girls tend to be more flexible in co- ordinating interpersonal goals. For instance, girls com- monly coordinate both affiliative and assertive goals in their social interactions (Leaper, 1991; Leaper & Smith, 2004). That is, girls are more likely than boys to use collaborative communication that affirms both the self and the other (e.g., proposals for joint activity), whereas boys are more likely than girls to use power- assertive communication that primarily affirms the self (e.g., giving commands). Girls, however, also fre- quently pursue play activities traditionally associated with boys, as in sports such as soccer and basketball. In contrast, it is relatively rare to see boys engage in activities traditionally associated with girls, such as playing house. Adolescence For some girls and boys, adolescence can be a period of either increased gender-role intensification (Galambos, Almeida, & Petersen, 1990; J. P. Hill & Lynch, 1983) or increased gender-role flexibility (D. B. Carter & Patterson, 1982; P. A. Katz & Ksansnak, 1994). Gender-role intensification refers to heightened concerns with adhering to traditional gender roles. Factors associated with ado- lescence, such as concerns with romantic attractiveness or conventional beliefs regarding adult gender roles, may intensify some youths’ adherence to traditional gender roles. Alternatively, advances in cognitive development can lead to greater gender-role flexibility, whereby adolescents may reject traditional gender roles as social conventions and pursue a flexible range of attitudes and interests (see Box 15.4). As in childhood, greater gender-role flexibility during adolescence is more likely among girls than among boys. For example, many girls and young women in the United States and other countries participate in sports and pursue careers in business (traditionally male-dominated domains), whereas relatively few boys and young men show similar levels of interest in child care or homemaking. During late childhood and adolescence, as children increasingly develop an understanding that norms about gender roles are social conventions, they may nev- ertheless endorse the conventions. Thus, adolescents may believe it is legitimate to exclude cross-gender peers from their peer group, because they feel that to include them would be violating the group’s gender norms and social conventions (Killen, 2007). Researchers also find that girls tend to perceive more gender discrimination during the course of adolescence (Leaper & Brown, 2008). This trend is likely due to a combination of experiencing increased sexism (American Association of University Women, 2011; S. E. Goldstein et al., 2007; McMaster et al., 2002) and having an in- creased awareness of sexism (C. S. Brown & Bigler, 2005; Leaper & Brown, 2008). Gender-Typed Behavior During early adolescence, peer contacts are primarily members of the same gen- der. However, cross-gender interactions and friendships usually become more common during adolescence (Poulin & Pedersen, 2007). As described in Chapter 13, these interactions can open the way to romantic relationships. Adolescence is also a period of increased intimacy in same-gender friendships. For many girls Gender segregation persists through child- hood. cross-gender teasing is used to main- tain gender boundaries. IN G R A M P U B LI S H IN G / S U P E R S T O C K gender-role intensification n height- ened concerns with adhering to tradi- tional gender roles that may occur during adolescence gender-role flexibility n recognition of gender roles as social conventions and adoption of more flexible attitudes and interests M I L E S T O N E S I N G E N D E R D E V E L O P M E N T n 613 Gender typing is more rigid for boys than for girls at all ages. Most boys engage almost exclusively in activities considered to be either masculine or gender-neutral, while many girls engage in activities stereotyped for boys (Bussey & Bandura, 1992; Fagot & Leinbach, 1993). This difference in gender flexibility seems to stem in large part from males’ avoidance of feminine- stereotyped activities in addition to their prefer- ence for masculine-stereotyped ones (Bussey & Bandura, 1992; C. L. Martin, Eisenbud, & Rose, 1995; Powlishta, Serbin, & Moller, 1993). By age 5, boys are more likely than girls to say that they dislike cross-gender-typed toys (Bussey & Bandura, 1992; Eisenberg-Berg, Murray, & Hite, 1982). The rigid preference for gender-typed objects and activities—along with the bias against cross-gender-typed objects and activities—declines during the school years; however, boys remain relatively stricter about gender typing than do girls (Serbin et al., 1993). One reason for boys’ greater avoidance of feminine-stereotyped activities is an asym- metry in the extent to which most people find it acceptable for boys and girls to en- gage in activities deemed more appropri- ate for the other gender. Generally, parents, peers, and teachers respond more negatively to boys who do “girl things” than vice versa. A child of one of this book’s authors, for instance, attended preschool with a girl who spent most of her time in the block-building area and a boy who, almost every day, selected a pink tutu from the dress-up cor- ner to wear over his clothes. The teachers, parents, and other adults who observed these two children were concerned about the boy’s behavior but not the girl’s behavior. Suppose you had a daughter who liked to play with toy soldiers and a son who liked to play with a baby doll. Would you find one of these more acceptable than the other? Also, imagine you heard another child call your daughter a “tomboy” or you heard someone refer to your son as a “sissy.” Would your reactions be different? According to one study, adults tended to find a “tomboy” girl considerably more acceptable than a “sissy” boy (C. L. Martin, 1990). Many fathers play an active role in nstilling male behaviors in their sons and in enforcing the avoidance of feminine behav- iors (Jacklin, DiPietro, & Maccoby, 1984; Leve & Fagot, 1997; P. J. Turner & Gervai, 1995). They generally react negatively to their sons for doing anything “feminine,” such as crying or playing with dolls. Consider the difference in what this mother and father say to their son when he hurts himself: Mother: “Come here, honey. I’ll kiss it better.” Father: “Oh, toughen up. Quit your bellyaching.” (Gable, Belsky, & Crnic, 1993, p. 32) Why are many parents and other adults more upset when boys engage in cross- gender-typed behaviors than they are when girls do? According to social identity theory (page 602) and social role theory (page 607), the asymmetry is tied to men’s higher status in society and the emphasis on dominance in the traditional male gender role. When boys show interest in feminine- stereotyped characteristics, people with traditional atti- tudes view the boys’ behavior as a loss in status. Conversely, when girls exhibit certain masculine-stereotyped qualities, those quali- ties are more likely to be seen as conferring status (Leaper, 1994). For example, a boy who wants to babysit may be ridiculed for being “soft,” but a girl who wants to play ice hockey may be praised for being “strong.” In many cultures, caring for children is viewed as a strength. Among the Aka hunter-gatherers in Africa, for example, child care is not viewed as a solely feminine activity and is in fact shared by men and women (Hewlett, 1991). A similar pattern is emerging among dual-career heterosexual parents in North America and other Western cultures. Many fathers are more involved in child care these days than was true in previ- ous generations (S. N. Davis & Greenstein, 2004). However, in most heterosexual families, mothers are usually responsible for most child care and housework (Sayer, 2005). BOX 15.4: a closer look GENDER FLEXIBILITY AND ASYMMETRY parents, peers, and teachers are much more tolerant of girls who engage in masculine-stereotyped activities than they are of boys who engage in feminine-stereotyped activities. JI M C U M M IN S / C O R B IS Fathers play an important role in encouraging boys to learn masculine- stereotyped behaviors. G U Y C A LI / C O R B IS 614 n chApter 15 GENDER DEVELOPMENT and boys, increased emotional closeness is often attained through sharing per- sonal feelings and thoughts, although there appears to be more variability among boys in the ways they experience and express closeness in friendships (Camarena, Sarigiani, & Petersen, 1990). While some boys attain intimacy through shared disclosures with same-gender friends, other boys tend to avoid self-disclosure with same-gender friends because they wish to appear strong. Instead, they usu- ally attain a feeling of emotional closeness with friends through shared activities, such as playing sports. At the same time, many boys who avoid expressing feel- ings with male friends will do so with their female friends or girlfriends (Youniss & Smollar, 1985). Self-disclosure and supportive listening are generally associated with rela- tionship satisfaction and emotional adjustment (Leaper & Anderson, 1997; Rubin, Bukowski, & Parker, 2006). However, it is possible to have too much of a good thing. This occurs when friends dwell too long on upsetting events by talking to one another about them over and over. As discussed in Chapter 10, this process of co-rumination is more common among girls than among boys (A. J. Rose, Carlson, & Waller, 2007). Although it may foster feelings of close- ness between friends, co-rumination appears to increase depression and anxiety in girls (but not in boys). review: By about 6 to 9 months of age, infants can distinguish between females and males on the basis of perceptual cues. Between ages 2 and 3 years, children identify their own gender, after which they begin acquiring stereotypes regarding culturally prescribed activities and traits associated with each gender. They also start to demonstrate gender-typed play prefer- ences. During the preschool period, children begin a process of self-initiated gender segrega- tion that lasts through childhood and is strongly enforced by peers. Around 7 years of age, children have acquired gender constancy and consolidated their understanding of gender. During middle childhood, children are capable of recognizing gen- der discrimination. Adolescence is a period that can involve increased gender-role rigidity or flexibility. It is also a time when girls are more likely to experience gender discrimination (sexism). Throughout childhood and adolescence, gender-role rigidity tends to be more com- mon among boys, and gender-role flexibility tends to be more common among girls. Friend- ship intimacy also increases during adolescence, although intimacy is more common among girls than among boys. Comparing Girls and Boys Given existing gender stereotypes as well as children’s early adoption of gender- typed behavior, you might assume that the actual differences between girls and boys are many and deep. Contrary to this assumption, as we will see in this sec- tion, only a few cognitive abilities, personality traits, and social behaviors actually show consistent gender differences, and most of those gender differences tend to be fairly small. When evaluating gender comparisons for different behaviors, it is often the case that one gender differs only slightly from the other: the overlap between gen- ders is considerable. Substantial variation also appears within each gender: not all members of the same gender are alike. Both these patterns appear in many observed gender differences studied by researchers. Therefore, besides knowing whether a group difference on some attribute is statistically significant—that C O M P A R I N G G I R L S A N D B O Y S n 615 is, unlikely to be caused by chance—it is important to consider both the magnitude of difference between two groups’ averages and the amount of overlap in their distributions. This statistical index, known as effect size, is illustrated in Figure 15.3. Researchers generally recognize four categories of effect sizes: trivial if the two distributions overlap more than 85%; small but meaningful if the distributions overlap between 67% and 85% (Figure 15.3a); medium if the distributions over- lap between 53% and 66% (Figure 15.3b); and large if the overlap is less than 53% (Figure 15.3c) ( J. Cohen, 1988). Thus, sometimes even a small group difference can be statistically significant. Across different research studies, contradictory findings are common regarding gender differences or similarities in particular outcomes. Contradictory findings can occur because studies vary in the characteristics of their samples (such as par- ticipants’ ages and backgrounds) and the methods used (such as surveys, naturalis- tic observation, or experiments). To infer overall patterns, scientists use a statistical technique known as meta-analysis to summarize the average effect size and statis- tical significance across studies. When available, in this section we have used meta- analyses to summarize research on gender differences and similarities. Table 15.1 on the next page compiles average gender differences and effect sizes for specific behaviors that we consider in this section. Because statistically significant gender differences in cognitive abilities and social behaviors are often in the small range of effect sizes, Janet Hyde (2005) has advocated “the gender similarities hypothesis.” She argued that, when comparing girls and boys, it is important to appreciate that similarities far outweigh differ- ences on most attributes. When reviewing research findings, we acknowledge this importance by noting in Table 15.1 whether the effect size of any average gender difference in behavior or cognition is trivial, small, medium, or large. Keep in mind, however, that even when there is a large average difference on any particular mea- sure, many girls and boys are similar to one another. Also, some members of the group with the lower average exceed some members of the group with the higher average (see Figure 15.3). For example, there is a very large average gender differ- ence in adult height. At the same time, many women and men are the same height, and some women are taller than the average man. Score (a) 85% overlap (small) (b) 66% overlap (medium) (c) 53% overlap (large) N u m b er o f ca se s Score Score FIGURE 15.3 effect sizes in three typical distributions of scores the effect sizes shown in graphs (a), (b), and (c) depict the overlap between males and females on three hypothetical dimen- sions and are typical of most gender differences. the distribution shown in yellow on each graph represents one gender, and the distribution shown in red represents the other gender. On many attri- butes, differences in average performance are statistically significant but very small, and the overlap between the scores for girls and boys is considerable. Note also the considerable variation on each graph within each gender, as revealed by the bell-shaped curves. effect size n magnitude of difference between two group’s averages and the amount of overlap in their distributions meta-analysis n statistical technique used to summarize average effect size and statistical significance across several research studies 616 n chApter 15 GENDER DEVELOPMENT TABLE 15.1 Summary of Average Gender Differences and effect Sizes for Gender-typed cognitions and Behaviors Statistically significant differences between two groups on any measure can range from trivial to very large. Guidelines for interpreting the effect size (magnitude of average difference) between two groups are based on the amount of overlap between the two groups’ distributions of scores (see Figure 15.3). When the overlap is greater than 85%, the difference is considered trivial. More meaningful differences are considered small if the overlap is between 67% and 85%, medium between 53% and 66%, and large if less than 53% (J. Cohen, 1988). In this table, an overlap less than 30% indicates a very large difference. Measure Age Range Average Finding* Effect Size Source Motor Abilities Physical strength Childhood B . G Medium J. R. Thomas & French, 1985 Adolescence B . G Very Large J. R. Thomas & French, 1985 Running speed Childhood B . G Medium J. R. Thomas & French, 1985 Adolescence B . G Very Large J. R. Thomas & French, 1985 Achievement and Test Performance Overall verbal ability Childhood G  B Trivial Hyde & Linn, 1988 Reading achievement Childhood G . B Small Nowell & Hedges, 1998 Writing achievement Childhood G . B Medium Nowell & Hedges, 1998 Spatial ability (mental rotation and spatial perception) Childhood and adolescence B . G Small Voyer et al., 1995 Math achievement Childhood B 5 G None Else-Quest et al., 2010; Lindberg et al., 2010 Adolescence B  G Trivial or none Else-Quest et al., 2010; Lindberg et al., 2010 Life sciences achievement Adolescence B 5 G None D. F. Halpern et al., 2007; Lindberg et al., 2010 Physical sciences achievement Adolescence B . G Small D. F. Halpern et al., 2007; Lindberg et al., 2010 Gender Stereotyping Childhood B . G Small Signorella et al., 1997 Gender-Typed Play Preference for feminine-stereotyped toys Childhood G . B Very large† Cherney & London, 2006 Preference for masculine-stereotyped toys Childhood B . G Very large† Cherney & London, 2006 Rough-and-tumble play Childhood B . G Large† DiPietro, 1981 Ability Beliefs Athletic self-concept Childhood and adolescence B . G Small Wilgenbusch & Merrell, 1999 Verbal self-concept Childhood and adolescence G . B Small Wilgenbusch & Merrell, 1999 Math self-concept Childhood and adolescence B . G Small Wilgenbusch & Merrell, 1999 Science self-concept Childhood and adolescence B . G Trivial Weinburgh, 1995 Computing self-concept Childhood B 5 G None Whitley, 1997 Adolescence B . G Medium Whitley, 1997 Personality Traits Activity level Infancy B . G Small Eaton & Enns, 1986 Childhood B . G Medium Eaton & Enns, 1986 Self-control Childhood G . B Small to large Else-Quest et al., 2006 Risk taking Childhood B . G Small Byrnes et al., 1999 Interpersonal Goals Dominance and control goals Childhood and adolescence B . G Small† A. J. Rose & Rudolph, 2006 Intimacy and support goals Childhood and adolescence G . B Medium† A. J. Rose & Rudolph, 2006 Communication with Peers Talkativeness Childhood and adolescence G 5 B None Leaper & Smith, 2004 Directive speech Childhood and adolescence B . G Small Leaper & Smith, 2004 Collaborative speech Childhood and adolescence G . B Small Leaper & Smith, 2004 Self-disclosure Childhood G . B Small† A. J. Rose & Rudolph,2006 Adolescence G . B Medium† A. J. Rose & Rudolph, 2006 Aggression Direct physical aggression Childhood and adolescence B . G Medium to large Archer, 2004; Card et al., 2008 Direct verbal aggression Childhood and adolescence B . G Small Archer, 2004; Card et al., 2008 Indirect aggression Childhood and adolescence G  B Trivial Card et al., 2008 *B indicates boys; G indicates girls. †Effect size not based on a meta-analysis but refers either to magnitude of difference seen in a single study or trend from a few studies summarized in the source. C O M P A R I N G G I R L S A N D B O Y S n 617 Physical Growth: Prenatal Development Through Adolescence Sex differences in physical development appear early in prenatal development. The most dramatic of these, of course, is the emergence of male or female genitalia. Thereafter, the differences that occur between males and females are relatively subtle—until the onset of puberty. In the following sections, we review the role of androgens in initiating prenatal sex differences; the average differences in male and female size, strength, and physical abilities in childhood; and the development of secondary sex characteristics in adolescence. Prenatal Development As should be clear from our earlier discussions, a key prenatal factor in sexual devel- opment is the presence or absence of androgens. Their presence, normally triggered by the Y chromosome in genetic males 6 to 8 weeks after conception, stimulates the formation of male external organs and internal reproductive structures; their absence results in the formation of female genital structures. In unusual circumstances known as intersex conditions (see Box 15.1), an overproduction of androgens may occur dur- ing prenatal development (congenital adrenal hyperplasia). In genetic females, this can lead to the formation of masculinized genitals. Conversely, a rare syndrome in genetic males (androgen insensitivity syndrome) causes the androgen receptors to malfunc- tion. In these cases, female external genitalia may form. Research suggests that prenatal exposure to androgens may influence the organization of the nervous system, and these effects may be partly related to some average gender differences in behavior seen at later ages. Infancy Early in life, males and females are quite similar in size, appearance, and abilities. At birth, males, on average, weigh only about half a pound more than females do; through infancy, male and female babies look so similar that, if they are dressed in gender-neutral clothing, people cannot guess their gender. Not surprisingly, it is quite easy to mislead people by, for example, dressing an infant boy in a girl’s outfit and call- ing him by a girl’s name. In fact, this “Baby X” technique has frequently been used to demonstrate the power of gender stereotypes. Adults who believe that they are play- ing with a boy are likely to encourage the infant to play with blocks and to offer the infant a toy football, even though the infant is really a girl (Bell & Carver, 1980). The technique is successful at revealing the influence of stereotyped expectations, because there are no consistent or obvious differences in how female and male infants actually look when they are clothed in a neutral manner or in how they behave. Childhood As discussed in Chapter 3, during childhood, girls and boys grow at roughly the same rate and are essentially equal in height and weight; however, on average, boys become notably stronger. With the changes in body composition that occur in early adolescence, particularly the substantial increase in muscle mass in boys, the gender gap in physical and motor skills greatly increases. After puberty, average gender differences are very large in strength, speed, and size: few adolescent girls can run as fast or throw a ball as far as most boys can (Malina & Bouchard, 1991; J. R. Thomas & French, 1985). These differences in motor abilities are among the largest seen between females and males (see Table 15.1). 618 n chApter 15 GENDER DEVELOPMENT Another average gender difference that increases in magnitude during child- hood is activity level (Eaton & Enns, 1986). As described in Chapter 10, activity level is a temperamental quality that refers to how much children tend to move and expend energy. On average, boys’ activity level tends to be higher than that of girls. In infancy, the difference is small, meaning that there is a lot of overlap between the distributions of the two genders (see Figure 15.3a). During childhood, the average gender difference in activity level increases to medium (Figure 15.3b). This increase may result from a combination of practice effects and the greater encouragement commonly given to boys to participate in sports and other physical activities (Leaper, 2013). At the same time, average gender differences in activity level also may contribute to children’s preferences for gender-typed play activities. Adolescence A series of dramatic bodily transformations during adolescence is associated with puberty, the developmental period marked by the ability to reproduce: for boys, to inseminate, and for girls, to menstruate, gestate, and lactate. In girls, puberty typi- cally begins with enlargement of the breasts and the general growth spurt in height and weight, followed by the appearance of pubic hair and then menarche, the onset of menstruation. Menarche is triggered in part by the increase in body fat that typi- cally occurs in adolescence. In boys, puberty generally starts with the growth of the testes, followed by the appearance of pubic hair, the general growth spurt, growth of the penis, and the capacity for ejaculation, known as spermarche (Gaddis & Brooks-Gunn, 1985; Jorgensen, Keiding, & Skakkebaek, 1991). For both sexes, there is considerable variability in physical maturation. The vari- ability in physical development is due to both genetic and environmental factors. Genes affect growth and sexual maturation in large part by influencing the produc- tion of hormones, especially growth hormone (secreted by the pituitary gland) and thyroxin (released by the thyroid gland). The influence of environmental factors is particularly evident in the changes in physical development that have occurred over generations (see Chapter 3). In the United States today, girls begin menstruating several years earlier than their ancestors did 200 years ago. This change is thought to reflect improvement in nutrition over the generations. The physical changes that boys and girls experience as they go through puberty are accompanied by psychological and behavioral changes. For example, in some cultures, the increase in body fat that girls experience in adolescence may be related to gender differences in body image—how an individual perceives and feels about his or her physical appearance. On average, American girls tend to have more nega- tive attitudes toward their bodies than boys do, and teenage girls typically want to lose several pounds regardless of how much they actually weigh (Tyrka, Graber, & Brooks-Gunn, 2000). A survey of more than 10,000 U.S. adolescents found that roughly half of boys and two-thirds of girls were dissatisfied with their bodies. Girls were mostly concerned about losing weight; boys, with being more muscular (A. E. Field et al., 2005). Dissatisfaction with body image has long been associated with a host of difficulties, ranging from low self-esteem and depression to eating disorders. This survey added another to the list: the use of unproven and potentially harmful substances to control weight or build muscle—a practice acknowledged by 12% of the boys and 8% of the girls surveyed. Another change that accompanies physical maturation is the onset of sexual attraction, which usually begins before the physical process of puberty is complete. According to the recollections of a sample of American adults, sexual attraction In early puberty, girls are typically taller than boys because of girls’ earlier physical maturation. By the end of adolescence, boys catch up and surpass girls in average height and weight. JU S T IN P U M F R E Y / G E T T Y I A M G E S puberty n developmental period marked by the ability to reproduce and other dra- matic bodily changes menarche n onset of menstruation spermarche n onset of capacity for ejaculation body image n an individual’s percep- tion of, and feelings about, his or her own body C O M P A R I N G G I R L S A N D B O Y S n 619 is first experienced at around 10 years of age— regardless of whether the attraction was for individ- uals of the other sex or the same sex (McClintock & Herdt, 1996). The onset of sexual attraction cor- relates with the maturation of the adrenal glands, which are the major source of sex steroids other than the testes and ovaries. This stage has been termed adrenarche, although the child’s body does not yet show any outside signs of maturation. (Sex- ual identity and romantic relationships are reviewed in Chapters 11 and 13.) Cognitive Abilities and Academic Achievement Although average gender differences have been reported for certain aspects of mental functioning, the amount of difference between girls’ and boys’ averages on achievement and test performance mea- sures is usually small (D. F. Halpern, 2012; see Table 15.1). Thus, the overlap between the two distribu- tions is large, with girls as well as boys scoring at the top and the bottom of the range. Nevertheless, despite the fact that the effect size of gender differences in abilities tends to be small, larger differences appear when it comes to interest and achieve- ment in particular subjects. The following sections summarize the evidence compar- ing boys’ and girls’ cognitive abilities and achievement; then we examine biological, cognitive- motivational, and cultural influences that might account for these findings. Understanding gender differences in this area is especially important because, to the extent that girls and boys develop different cognitive abilities, academic interests, and achievement, gender differences in their future occupations and pay may follow. General Intelligence Despite widespread belief to the contrary, boys and girls are equivalent in most aspects of intelligence and cognitive functioning. The average IQ scores of girls and boys are virtually identical (D. F. Halpern, 2004; Hyde & McKinley, 1997). However, proportionally more boys’ than girls’ scores fall at both the lower and the upper range of scores. That is, somewhat more boys than girls are diagnosed with intellectual disabilities or classified as intellectually gifted (D. F. Halpern, 2012). Overall Academic Achievement Although girls and boys are similar in general intelligence, they tend to differ in academic achievement from elementary school through college. Recent statis- tics in the United States indicate that girls tend to show higher levels of school adjustment and achievement than do boys (T. D. Snyder & Dillow, 2010). For exam- ple, in 2010, the high school dropout rate was higher for boys (9.3%) than for girls (6.5%). In addition, in that same year, 57% of bachelor’s degrees were awarded to women. In terms of ethnic groups, the magnitude of gender difference in academic achievement is higher among Hispanic or African American youth than it is among European American or Asian American youth. Adrenarche, the onset of sexual interest, has been linked to the maturation of the adrenal glands, which produce sex steroid hormones in both boys and girls. E X A C T O S T O C K / S U P E R S T O C K adrenarche n period prior to the emer- gence of visible signs of puberty during which the adrenal glands mature, pro- viding a major source of sex steroid hor- mones; correlates with the onset of sexual attraction 620 n chApter 15 GENDER DEVELOPMENT In addition to the overall differences in academic achievement, for some specific cognitive abilities and academic subjects, one gender tends to excel slightly more than the other. Verbal Skills Compared with boys, girls tend to be slightly advanced in early language develop- ment, including fluency and clarity of articulation and vocabulary development (Gleason & Ely, 2002). On standardized tests of children’s overall verbal ability, a negligible average gender difference favors girls (Hyde & Linn, 1988). Larger average differences are seen when specific verbal skills are examined. Girls tend to achieve higher average performance in reading and writing from elementary school into high school; the effect size of the average differences was small for reading and medium for writing (Hedges & Nowell, 1995; Nowell & Hedges, 1998; see Table 15.1). Boys are more likely to suffer speech-related problems, such as poor articu- lation and stuttering, as well as more reading-related problems such as dyslexia (D. F. Halpern, 2012). Spatial Skills On average, boys tend to perform better than girls do in some aspects of visual- spatial processing (see Table 15.1). This difference emerges between 3 and 4 years of age and becomes more substantial during adolescence and adulthood (D. F. Halpern, 2012). Gender differences are most pronounced on tasks that involve mental rotation of a complex geometric figure in order to decide whether it matches another figure presented in a different orientation (Figure 15.4a). However, other spa- tial tasks, such as finding a hidden figure embedded within a larger image, show much smaller gender differences (Figure 15.4b). Thus, the conclusion that more males than females have superior spatial ability depends on the particular type of spatial ability. Mathematical and Related Skills Until recent decades in the United States, boys tended to perform somewhat better on standardized tests of mathematical ability than did girls. As we have noted, how- ever, the gender gap in mathematics achievement has closed dramatically as a result of efforts made by schools to improve girls’ performance. Boys and girls currently Standard (a) Mental Rotation (b) Spatial Visualization Responses FIGURE 15.4 tests of spatial skills Gender differences vary according to the type of task. Boys tend to perform better than girls do on tasks that involve mental rotation, such as the one in (a), in which children have to determine which response matches the standard. In contrast, gender differences are small or nonexistent on tasks like that in (b), which requires children to find the simple geometric figure on the left embedded in the adjoining complex figure. (Adapted from Linn & peterson, 1985) C O M P A R I N G G I R L S A N D B O Y S n 621 are near parity in performance on standardized tests at the high school level (D. F. Halpern et al., 2007; Nowell & Hedges, 1998; see Table 15.1). Furthermore, U.S. girls and women are maintaining their interest in math beyond high school at rates higher than seen in earlier decades. The percentage of bachelor’s degrees in math- ematics awarded to women in the United States increased from 37% in 1970 to 43% in 2010 (National Science Foundation, 2013; T. D. Snyder & Dillow, 2010). Mathematics is considered a key gateway for careers in science, technology, and engineering (D. F. Halpern et al., 2007; Watt, 2006). Patterns of gender differ- ences in these subject areas are mixed in the United States. In the life sciences (e.g., biology), girls and women appear to be doing well. At the high school level, there is no average gender difference in achievement. At the college level, women earned 59% of recent bachelor’s degrees in biological sciences (National Science Founda- tion, 2013). In contrast, girls and women are not as well represented in the physical sciences (e.g., physics) and technological fields (e.g., engineering). Among recently awarded bachelor’s degrees, for example, women accounted for 20% in physics, 18% in com- puter science, and 18% in engineering (National Science Foundation, 2013). Fol- lowing the attention paid to the gender gap in math achievement a few decades ago, educators and researchers are increasingly addressing the gender gap in the physical sciences and technology. Explanations for Gender Differences in Cognitive Abilities and Achievement Researchers have variously pointed to biological, cognitive-motivational, and cultural factors in relation to gender-related variations in cognitive abilities and achievement. We now examine each possible area of influence. Biological influences Some researchers have proposed that sex differences in brain structure and function may underlie some differences in how male and female brains process different types of information. However, because the research supporting this interpretation has often been based on adults, it is impos- sible to determine whether any differences in brain structure and function are due to genetic or environmental influences. Also, a slight biological difference can get exaggerated through differential experience (D. F. Halpern, 2012). For example, boys may initially have a slight average advantage over girls in some types of spa- tial processing. However, when boys spend more time playing video games and sports than girls do, they practice their spatial skills more (Moreau et al., 2012; I. Spence & Feng, 2010). As a consequence, the magnitude of the gender differ- ence in spatial ability may widen. Stronger evidence for possible biological influences is suggested by research showing that some sex differences in brain structure may be partly due to the influ- ence of sex-related hormones on the developing fetal brain (Hines, 2004). Andro- gens may affect parts of the brain associated with spatial skills (Grön et al., 2000), for example. Because males are exposed to higher levels of androgens than are females during normal prenatal development, this difference may lead to greater hemispheric specialization in the male brain and more proficiency in spatial abil- ity later in life. Support for this hypothesis comes from studies that have linked very high levels of prenatal androgens in girls with above-average spatial ability (Grimshaw, Sitarenios, & Finegan, 1995; Hines et al., 2003; Mueller et al., 2008). Conversely, it has been found that males with androgen insensitivity syndrome (see 622 n chApter 15 GENDER DEVELOPMENT Box 15.1) tend to score lower-than-average in spatial ability (Imperato- McGinley et al., 1991/2007). As discussed in Chapters 6 through 9, boys are more vulnerable than girls to developmental disorders of mental functioning such as autism, attention-deficit hyperactivity disorder, and language-related and in- tellectual disabilities (T. Thompson, Caruso, & Ellerbeck, 2003). Some researchers have argued that these differences may be linked to dif- ferences in brain organization and sex hormones. For example, higher rates of attention problems and language-related disorders in boys might be linked to unusually high levels of androgen exposure during prenatal development (Tallal & Fitch, 1993). cognitive and motivational influences The process of self- socialization emphasized in cognitive-motivational theories plays a role in children’s academic achievement. According to Eccles’s expectancy- value model of achievement (Eccles & Wigfield, 2002), children are most motivated to achieve in areas in which they view themselves as competent (expectations for success) and find interesting and important (value). Gender stereotypes can shape the kinds of subjects that girls and boys tend to value (see Table 15.1). For instance, many children internalize gender stereotypes that science, technology, and math are for boys and that reading, writing, and the arts are for girls (Archer & Macrae, 1991; J. M. Whitehead, 1996). Perhaps it is not sur- prising, then, that average gender differences in interest and ability beliefs exist in these academic areas (Eccles & Wigfield, 2002; Wigfield et al., 1997; Wilgenbusch & Merrell, 1999) and that these self-concepts predict academic achievement and occupational aspirations (Bussey & Bandura, 1999; Eccles & Wigfield, 2002; D. F. Halpern et al., 2007). As discussed next, parents, teachers, peers, and the sur- rounding culture can influence the development of girls’ and boys’ academic self- concepts and achievement through the role models, opportunities, and motivations that they provide for practicing, or not practicing, particular behaviors. PARENTAL INFLUENCES As noted in Chapter 6, parents’ talking to their children is a strong predictor of children’s language learning. A meta-analysis found that moth- ers tended to have higher rates of verbal interaction with daughters than with sons (Leaper, Anderson, & Sanders, 1998). Thus, one possibility is that young girls learn language a bit faster than boys do simply because mothers spend more time talking with daughters than sons. Conversely, girls’ faster language acquisi- tion may lead mothers to talk more to them than to their sons (Leaper & Smith, 2004). Finally, both patterns may tend to occur—a possible bidirectional influence whereby both mothers and daughters tend to be talkative and reinforce this behav- ior in one another. Parents’ gender stereotyping (see Box 15.2) is also related to children’s academic achievement. Many parents accept the prevailing stereotypes about boys’ and girls’ relative interest in and aptitude for various academic subjects (Eccles et al., 2000; Leaper, 2013), and these gender-typed expectations can affect children’s achieve- ment motivation (Eccles et al., 2000). Observational research suggests that parents may communicate their own gender-stereotyped expectations to their children through differential encouragement (Bhanot & Jovanovic, 2005; Crowley et al., 2001; Tenenbaum & Leaper, 2003). You might think that parents’ beliefs about their children’s academic potential would be based primarily on their children’s own self-concepts and achievement, but researchers find that parents often hold these Attention problems in girls may often go unrecognized because girls’ symptoms do not match the standard descriptions of attention problems, which are based on male symptoms. A girl with attention dif- ficulties may be overlooked or described as a daydreamer by her teacher because her behavior is not disruptive to the class. D E S IG N P IC S I N C . / A LA M Y Some studies find that mothers are more talkative with daughters than with sons. Studies also find that, on average, girls acquire language at a faster rate than do boys. Does mothers’ greater talkativeness with girls contribute to girls’ faster language acquisition? Or does girls’ faster language acquisition influence mothers’ talkativeness with them? P H O T O D IS C / G E T T Y I M A G E S C O M P A R I N G G I R L S A N D B O Y S n 623 beliefs before any average gender differences in academic interest or performance occur. In fact, longitudinal research indicates that parents’ expectations can be a stronger predictor of children’s later achievement than the children’s earlier perfor- mance in particular subject areas (Bleeker & Jacobs, 2004). TEACHER INFLUENCES Teachers can influence gender differences in children’s aca- demic motivation and achievement in two important ways. First, teachers them- selves are sometimes influential gender-role models. Having women as science teachers, for example, may increase girls’ interest in science careers (M. A. Evans, Whigham, & Wang, 1995). Second, many teachers hold gender-stereotyped beliefs about girls’ and boys’ abilities. For example, some teachers may expect higher school achievement in girls than in boys (S. Jones & Myhill, 2004), or they may stereotype boys as being better at math and science (Shepardson & Pizzini, 1992; Tiedemann, 2000). When teachers hold gender-typed expectations, they may dif- ferentially assess, encourage, and pay attention to students according to their gen- der. In this manner, teachers can lay the groundwork for self-fulfilling prophecies that affect children’s later academic achievement (see D. F. Halpern et al., 2007; Jussim, Eccles, & Madon, 1996). PEER INFLUENCES Children’s interests often are shaped by the activities and values they associate with their classmates and friends. Consequently, peers can shape children’s academic achievement. This influence begins with the kinds of play activities that children practice with their peers. As we have noted, many activ- ities favored by boys—including construction play, sports, and video games— provide them with opportunities to develop their spatial abilities as well as math- and science-related skills (Serbin et al., 1990; Subrahmanyam et al., 2001). The types of play more common among girls—such as domestic role-play—are talk- oriented and build verbal skills (Taharally, 1991). Girls and boys may be more likely to achieve in particular school subjects when they are viewed as compatible with peer norms. For example, one study found teachers are more likely to call on boys than on girls. One reason may be that, on average, girls earn higher grades than boys; thus, some teachers may tend to focus their attention on lower-achieving students. Another reason may be that boys are more assertive in raising their hands and shouting out answers.VS T O C K / A LA M Y 624 n chApter 15 GENDER DEVELOPMENT that U.S. high school students who viewed their friends as supportive of science and math were more likely to express interest in a future science-related career (Robnett & Leaper, 2013). The association between friends’ science support and science career interest held for both girls and boys—but boys were more likely than girls to report having a friendship group supportive of science. It is also notable that friends’ support of English (reading and writing) was not related to science career interest; thus, peer norms regarding particular academic subjects may be related to how likely girls or boys are to value those subjects. Traditional masculinity norms emphasizing dominance and self-reliance may undermine some boys’ academic achieve- ment in the United States and other Western countries (Levant, 2005; Renold, 2001; Steinmayr & Spinath, 2008; Van Houtte, 2004). That is, some boys may not consider it masculine to do well in certain subjects or possibly in school overall. For example, doing well in school or expressing interest in certain subjects, such as reading, may be devalued as being feminine (Andre et al., 1999; Martinot, Bagès, & Désert, 2012; J. M. Whitehead, 1996). Indeed, some research suggests that boys’ endorsement of traditional masculinity is related to lower average performances in reading and writing and lower rates of high school graduation in North America and Europe (Levant, 2005; Renold, 2001; Steinmayr & Spinath, 2008; Van de Gaer et al., 2006; Van Houtte, 2004). At the same time, some U.S. research suggests that gender-role flexibility is re- lated to holding more positive scholastic self-concepts in adolescent boys (A. Rose & Montemayor, 1994), as well as to stronger interest in nontraditional majors among male undergraduates ( Jome & Tokar, 1998; Leaper & Van, 2008). CULTURAL INFLUENCES Social role theory maintains that socialization practices pre- pare children for their adult roles in society. If women and men tend to hold dif- ferent occupations, then different abilities and preferences are apt to be encouraged in girls and boys. Therefore, where there are cultural variations in girls’ and boys’ academic achievement, there should be corresponding differences in socialization. A meta-analysis conducted by Else-Quest, Hyde, and Linn (2010) pointed to cultural influences on gender-related variations in mathematics achievement. Gen- der differences on standardized math tests varied widely across nations: in some, boys scored higher; in others, girls scored higher; and in still others, no gender dif- ference appeared. To assess possible cultural influences, the researchers considered the representation of women in higher education in the country. They found that average gender differences in several math-related outcomes were less likely in nations with higher percentages of women in higher levels of education. This was seen for adolescents’ test performance, self-confidence, and intrinsic motivation regarding math. As we noted earlier, the narrowing gender gap in math achieve- ment in the United States over the past few decades was accompanied by a steady increase in the proportion of women in science and engineering (National Science Foundation, 2013). Other cultural factors have also been found to predict gender-related variations in academic achievement within American society. Average gender differences in overall academic success and verbal achievement tend to be less common among children from higher-income neighborhoods and among children of highly edu- cated parents (Burkam, Lee, & Smerdon, 1997; DeBaryshe, Patterson, & Capaldi, peer norms can have a strong impact on girls’ and boys’ achievement motivation. For example, research indicates that girls are more likely to maintain their interest in sci- ence and computers when their friends sup- port achievement in these subjects. N A N D A N A D E S IL VA / A LA M Y C O M P A R I N G G I R L S A N D B O Y S n 625 1993; Ferry, Fouad, & Smith, 2000). Gender differences in achievement may also be less common among children of gender-egalitarian parents. One study found that adolescent girls raised by egalitarian parents maintained higher levels of aca- demic achievement in middle school—especially in math and science—compared with girls raised by more traditional parents (Updegraff, McHale, & Crouter, 1996). Personality Traits During childhood, average gender differences appear in some personality traits, including activity level, self-regulation, and risk-taking (see Table 15.1). Keep in mind, however, that there is much overlap between girls and boys. In other words, many girls and boys express similar personality traits. Also, there is variation within each gender in personality. Not all girls are alike, and not all boys are alike. Activity level Higher average activity levels are seen among boys than among girls during child- hood. The effect size is medium, which means that there is a meaningful average difference (although there is also much overlap between the two genders). Chil- dren’s activity levels may partly underlie some average differences between girls and boys in how much they prefer active versus sedentary forms of play—such as sports and doll play, respectively. Self-Regulation As discussed in Chapter 10, self-regulation refers to children’s ability to control their own emotions and behavior, to comply with adults’ directions, and to make good decisions when adults are not around. Research indicates that girls tend to show higher levels of self-regulation and lower impulsivity than do boys of the same age—with the average gender difference being in the small-to-large range, depending on the type of measure used (Else-Quest et al., 2006). Given the average gender difference in self-regulation, perhaps it is not surprising that, on average, girls are more compliant with adult directives and expectations than boys are (C. L. Smith et al., 2004). As discussed later, average gender differences in self- regulation and impulsivity may partly contribute to higher incidences of direct physical aggression among boys than girls. Risk Taking A third personality trait associated with average gender differences during child- hood is risk taking. There is a small average difference across studies indicating that boys are more likely than girls to engage in many types of risky behavior (Byrnes, Miller, & Schafer, 1999). When boys and girls encounter the same hazardous situ- ation, for example, girls are more cautious, on average, and often point out the haz- ard to a parent. In contrast, boys are more likely to approach and explore the hazard (Fabes, Martin, & Hanish, 2003). Explanations for Gender Differences in Personality As with other aspects of gender development, there is evidence for both biological and cognitive-motivational influences on average gender differences in personality. Activity level and impulse control are temperamental qualities that are partly based Boys tend to be less compliant with adult instructions and expectations than girls are. Boys are also more likely than girls to engage in risky behaviors, leading to higher rates of injury and death for boys. D E N N IS M A C D O N A LD / P H O T O E D IT 626 n chApter 15 GENDER DEVELOPMENT on genetic predispositions (see Chapter 10). In addition, environmental factors— such as parents’ and peers’ reactions—can exaggerate or attenuate temperamen- tal dispositions (Goldsmith, Buss, & Lemery, 1997). For instance, some parents encourage athletic participation more in sons than in daughters. Also, peer pres- sures on boys to participate in sports are often stronger than on girls (see Leaper, 2013). As a consequence of these socialization practices, preferences for physical activity may strengthen in boys and weaken in girls. Interpersonal Goals and Communication One of the most popular self-help books about relationships has been John Gray’s (1992) Men Are from Mars, Women Are from Venus. The author (who is not a scien- tist) purported that gender differences in interpersonal goals and communication style are so great that it is almost as if the sexes came from different planets. The scientific evidence, however, indicates that average gender differences in adults’ communication are not nearly as dramatic as Gray portrayed them. Although average gender differences in women’s and men’s speech have been documented, the magnitude of the differences has usually been in the small-to-medium range (Leaper & Ayres, 2007). The average gender differences in communication and interpersonal goals during childhood and adolescence have likewise been found to be modest (see Table 15.1). In terms of interpersonal goals, researchers have found average gender differ- ences that are consistent with traditional gender roles (A. J. Rose & Rudolph, 2006). More boys than girls tend to emphasize dominance and power as goals in their social relationships. In contrast, more girls than boys tend to favor intimacy and support as goals in their relationships. The effect sizes for these differences tend to be small to moderate. Researchers have also observed some average gender differences among chil- dren in communication style with their peers. Contrary to the stereotypes of talk- ative girls and taciturn boys, studies generally do not find average differences in talkativeness after early childhood (Leaper & Smith, 2004). However, with regard to self-disclosure about personal thoughts and feelings, there tends to be a small- to-medium gender difference, with higher average rates among girls than boys (A. J. Rose & Rudolph, 2006). Girls also tend to be somewhat more likely than boys to use collaborative statements, which reflect high affiliation and high asser- tion. In contrast, boys tend to be more likely than girls to use directive statements, which reflect high assertion and low affiliation (see Box 15.5). cognitive and motivational influences The average gender differences in inter- personal goals and communication style are related. To the extent that some girls and boys differ in their primary goals for social relationships, they are apt to use dif- ferent language styles to attain those goals (P. M. Miller, Danaher, & Forbes, 1986; Strough & Berg, 2000). For example, if a boy is especially interested in establishing dominance, using directive statements may help him attain that goal; and if a girl wants to establish intimacy, then talking about personal feelings or elaborating on the other person’s thoughts would help realize that goal. parental influences Many children may observe their parents modeling gender- typed communication patterns. A meta-analysis comparing mothers’ and fathers’ speech to their children indicated small average effect sizes, with mothers more C O M P A R I N G G I R L S A N D B O Y S n 627 BOX 15.5: a closer look GENDER AND CHILDREN’S COMMUNICATION STYLES Several studies conducted by Leaper and col- leagues have examined gender-related varia- tions in children’s and adults’ communication patterns (e.g., Leaper, 1991; Leaper et al., 1999; Leaper et al., 1995; Leaper & Gleason, 1996; Leaper & Holliday, 1995). In one study of 5- and 7-year-olds, Leaper (1991) placed children in same- or mixed-gender pairs to play with a set of hand puppets. He recorded the children’s conversation and classified each statement the children made in terms of affiliation and assertion. As diagrammed in the figure below, a statement can be high or low on each dimension, which allows for four speech act (statement) categories: 1. Collaborative statements are high in both affiliation (engaging the other per- son) and assertion (guiding the action). Examples include suggestions for joint activity (“Let’s play superheroes”) or elaborations on what the other speaker previously said. 2. Controlling statements are high in assertion but low in affiliation. Examples include directives (“Do this”) or negative comments. 3. Obliging statements are high in affili- ation and low in assertion. Examples include expressions of agreement or going along with the other’s proposal (“Sure, that’s fine”). 4. Withdrawing acts reflect low asser- tion and low affiliation. This includes being nonresponsive to another person’s statement. For girls and boys in both age groups, collaborative conversations were the most common. There were no average gender dif- ferences in any of the types of statements among the younger children and there were no average differences in obliging state- ments or withdrawing acts among the older children. However, significant gender differ- ences were seen among the older children in the percentages of collaborative and control- ling statements. Among the 7-year-olds, the average percentage of collaborative state- ments was significantly higher among girl– girl pairs (mean 5 56%) than either boy–boy pairs (mean 5 39%) or mixed- gender pairs (mean 5 43%). Following is an example of reciprocal col- laboration between one pair of girls. The type of speech act is indicated in brackets next to each statement. Jennifer: Let’s go play on the slide. (Makes sliding noises) [Collaborate] Sally: Okay. [Oblige] (Makes sliding noises) I’ll do a choo-choo train with you. [Collaborate] Jennifer: Okay. [Oblige] Sally: You can go first. [Collaborate] Jennifer: Ch . . . (Gasp) [Collaborate] Sally: Ch . . . (Gasp) [Collaborate] (Leaper, 1991, p. 800) Another average gender difference was the percentage of controlling speech. Rates were significantly lower in girl–girl pairs (mean 5 13%) than either boy–boy pairs (mean 5 26%) or mixed-gender pairs (mean 5 24%). Within the mixed-gender pairs, no gender differences appeared in collaborative or con- trolling speech. Thus, it appears that girls tended to decrease their amount of collab- orative speech and increase their use of con- trolling speech when interacting with boys (compared with when they are interacting with girls). Conversely, boys tended to use similar amounts of collaborative and con- trolling speech in same-gender and mixed- gender interactions. According to Leaper (1991), it is impor- tant to acknowledge, first, that collaboration was the most common type of speech for both girls and boys. Despite this similarity, collaboration was even more frequent in the average speech of girls than of boys. Con- versely, controlling speech was more com- mon among boys than among girls. Contrary to old stereotypes of girls being unassert- ive, girls were not more likely than boys to make statements low in assertion (oblig- ing speech or withdrawing). Instead, girls were more likely to coordinate affiliative and assertive goals in their communication. Finally, in mixed-gender interactions, there was more evidence of girl’s accommodat- ing to the speech style of boys than the reverse; that is, girls tended to show more of the pattern associated with boys’ same- gender interactions (more controlling and less collaborative speech) during mixed- gender interactions, whereas boys tended to show similar average patterns in same- and mixed-gender interactions. Withdrawal Low assertion and low affiliation Example: • Not responding to another person’s statement Obliging Statements High affiliation and low assertion Examples: • Expressions of agreement • Going along with the other’s proposal (“Sure, that’s fine.”) Collaborative Statements High affiliation and high assertion Examples: • Suggestions for joint activity (“Let’s play superheroes.”) • Elaborations on what the other speaker previously said Controlling Statements High assertion and low affiliation Examples: • Directives (“Do this.”) • Negative comments Affiliation A ss er ti on Low High High communication styles the figure illustrates the two-dimensional model of social interac- tion and communication. Assertion ranges from high to low along the vertical axis, and affiliation ranges from high to low along the horizontal axis. collaborative acts are high in both affiliation and assertion. controlling acts are high in assertion and low in affiliation. Obliging acts are high in affiliation and low in assertion. Withdrawing acts are low in both affiliation and assertion. 628 n chApter 15 GENDER DEVELOPMENT likely than fathers to use affiliative speech; in contrast, fathers were more likely than mothers to use controlling (high in assertion and low in affiliation) speech (Leaper, Anderson, & Sanders, 1998). peer influences The social norms and activities traditionally practiced within children’s gender-segregated peer groups foster different interpersonal goals in girls and boys. For example, many girls commonly engage in domestic scenarios (“play- ing house”) that are structured around collaborative and affectionate interchanges. Boys’ play is more likely to involve competitive contexts (“playing war” or sports) that are structured around dominance and power. The impact of same-gender peer norms was implicated in Leaper and Smith’s (2004) meta-analysis in which it was found that gender differences in communication were more likely to be detected in studies of same-gender interactions than in mixed-gender interactions. Aggressive Behavior The conventional wisdom is that boys are more aggressive than girls are. In sup- port of this expectation, research studies indicate a reliable gender difference in aggression. However, the magnitude of the gender difference is not as great as many people expect. Also, it depends partly on the type of aggression being considered. As noted in Chapter 13, researchers distinguish between direct and indirect forms of aggression (Archer & Coyne, 2005; Björkqvist, Österman, & Kaukiainen, 1992). Direct aggression involves overt physical or verbal acts openly intended to cause harm, whereas indirect aggression (also known as relational or social aggres- sion) involves attempts to damage a person’s social standing or group acceptance through covert means such as negative gossip and social exclusion. Average gender differences in the incidence of physical aggression emerge gradu- ally during the preschool years (D. F. Hay, 2007). In a comprehensive meta-analysis of studies comparing boys’ and girls’ aggressive behavior, John Archer (2004) found that both physical and verbal forms of direct aggression occurred more often among boys than among girls. The average difference was small during childhood and moderate to large during adolescence. Although direct aggression generally declines for both boys and girls with age, the decline is more pronounced for girls than for boys. There appears to be no average gender difference during child- hood in the use of indirect aggression. In a meta-analysis of stud- ies testing for such gender differences, Card and colleagues (2008) found only a negligible effect size during adolescence, with girls slightly more likely than boys to use indirect aggression. The trivial effect size may seem surprising given the popular notion of “mean girls” who use indirect strategies such as negative gossip and social exclusion. However, because direct aggression is less likely among girls than boys, girls tend to use proportionally more indirect than direct aggression than boys, on average. Thus, when most girls do express aggression, it may be indirect rather than direct physical or verbal aggression (Leaper, 2013). Although there may not be much difference between girls and boys in the average use of indirect aggression, being the target of indirect aggression may more often cause problems for girls than boys (Crick & Grotpeter, 1996). This may occur because girls’ friendships tend to be exclusive and intimate, whereas boys’ rates of indirect aggression are higher for girls than for boys. Indirect aggression includes behaviors such as criticizing and spreading rumors about a peer or excluding a peer from the friendship group. S P E N C E R G R A N T / P H O T O E D IT C O M P A R I N G G I R L S A N D B O Y S n 629 friendships tend to be embedded within a larger peer group (Benenson et al., 2002; A. J. Rose & Rudolph, 2006). Nonetheless, all forms of aggression can have negative effects on both girls and boys. Average gender differences in aggression have been found primarily in research on same-gender interactions. Research conducted with mostly European American children suggests that different rules may apply when some girls and boys have con- flicts with one another. Beginning in early childhood, boys are more likely than girls to ignore the other gender’s attempts to exert influence ( Jacklin & Maccoby, 1978; Serbin et al., 1982). Thus, when they are more assertive and less affiliative, boys may be more apt to get their way in unsupervised mixed-gender groups (Charlesworth & LaFreniere, 1983). Studies comparing children’s behavior in same-gender versus cross-gender con- flicts revealed another interesting pattern. In same-gender conflicts, boys were more likely to use power-assertive strategies (e.g., threats, demands) and girls were more likely to use conflict-mitigation strategies (e.g., compromise, change the topic). However, in cross-gender conflicts, girls’ use of power-assertive strategies increased, but boys’ use of conflict-mitigation strategies did not change (P. M. Miller et al., 1986; Sims, Hutchins, & Taylor, 1998). These studies suggest that girls often may find it necessary to play by the boys’ rules to gain influence in mixed-gender settings. Explanations for Gender Differences in Aggression Possible explanations for gender differences in aggression range from the effects of biological factors to the socializing influences of family, peers, the media, and the culture at large. Each factor likely has a contributing role. Biological influences It is well known that, on average, males have higher base- line levels of testosterone than do females, and many people assume that this accounts for gender differences in aggression. Contrary to this popular belief, there is no direct association between aggression and baseline testosterone levels (Archer, Graham-Kevan, & Davies, 2005). However, there is an indirect one: the body increases its production of testosterone in response to perceived threats and challenges, and this increase can lead to more aggressive behavior (Archer, 2006). Furthermore, people who are impulsive and less inhibited are more likely to per- ceive the behavior of others as threatening. Thus, because boys, on average, have more difficulty regulating emotion (Else-Quest et al., 2006), they may be more prone to direct aggression (D. F. Hay, 2007). Conversely, greater emotion regula- tion among girls may contribute to higher rates of prosocial behavior. cognitive and motivational influences Average gender differences in empa- thy and prosocial behavior may be related to differences in boys’ and girls’ rates of aggression (Knight, Fabes, & Higgins, 1996; Lemerise & Arsenio, 2000; Levant, 2005; Mayberry & Espelage, 2007). On average, girls are somewhat more likely than boys to report feelings of empathy and sympathy in response to people’s distress (N. Eisenberg & Fabes, 1998), and they also tend to display more concern in their behavioral reactions (e.g., looks of concern and attempts to help). Direct aggres- sion may be more likely among children who are less empathetic and have fewer prosocial skills. In support of this explanation, one study found average gender differences, with boys scoring higher on direct aggression and lower on empathy than girls, but both aggressive girls and aggressive boys scored lower on empathy than did nonaggressive girls and boys (Mayberry & Espelage, 2007). 630 n chApter 15 GENDER DEVELOPMENT The gender-typed social norms and goals regarding assertion and affiliation may further contribute to the average gender difference in conflict and aggression (P. M. Miller et al., 1986; A. J. Rose & Rudolph, 2006; see Table 15.1). More boys than girls tend to favor assertive over affiliative goals (e.g., being dominant), whereas more girls than boys tend to endorse affiliative goals or a combination of affiliative and assertive goals (e.g., maintaining intimacy). When some boys focus on dominance goals, they may be more likely to appraise conflicts as competitions that require the use of direct aggression. In addition, some boys may initiate direct aggression as a way to enhance their status. In contrast, by emphasizing intimacy and nurturance goals, many girls may be more likely to view relationship conflicts as threats that need to be resolved through compromise that preserves harmony (P. M. Miller et al., 1986). The normative social pressures among many girls to act “nice” may also lead them to avoid direct confron- tation. However, when girls who adhere to these norms are unable to resolve a con- flict, they may try to hurt one another through indirect strategies such as criticizing or excluding the offender or sharing secret information about the offender with other girls (Crick, Bigbee, & Howes, 1996; Galen & Underwood, 1997). This may be one reason for a paradox noted in Chapter 13: Even though girls, on average, have more intimate friendships than do boys, girls’ same-gender friendships tend to be less sta- ble over time (Benenson & Christakos, 2003). That is, when conflict occurs in same- gender friendships and indirect aggression occurs, girls may be more likely than boys to take it personally and see it as a reason to end the relationship. parental and other adult influences In general, most parents and other adults disapprove of physical aggression in both boys and girls. After the preschool years, however, they tend to be more tolerant of aggression in boys and often adopt a “boys will be boys” attitude toward it ( J. Martin & Ross, 2005). In an experimental demonstration of this effect, researchers asked people to watch a short film of two children engaged in rough-and-tumble play in the snow and to rate the level of the play’s aggressiveness (Condry & Ross, 1985). The children were dressed in gender- neutral snowsuits and filmed at a distance that made their gender undeterminable. Some viewers were told that both children were male; others, that they were both female; and still others, that they were a boy and girl. Viewers who thought that both children were boys rated their play as much less aggressive than did viewers who thought that both children were girls. Children also appear aware of this “boys will be boys” bias and believe that phys- ical aggression is more acceptable, and less likely to be punished, when enacted by boys than when enacted by girls (Giles & Heyman, 2005; Perry, Perry, & Weiss, 1989). Thus, girls’ reliance on strategies of aggression that are covert—and easily denied if detected—may reflect their recognition that displays of physical aggres- sion on their part will attract adult attention and punishment. Parenting style may also factor into children’s manifestations of aggression. Harsh, inconsistent parenting and poor monitoring increase the likelihood of physical ag- gression in childhood (Leve, Pears, & Fisher, 2002; Vitaro et al., 2006). Children who experience such parenting may learn to mistrust others and make hostile attri- butions about other people’s intentions (Crick & Dodge, 1996). The association be- tween harsh parenting and later physical aggression is stronger for boys than for girls. Also, as noted in Chapter 14, poor parental monitoring increases children’s suscepti- bility to negative peer influences and is correlated with higher rates of aggression and delinquency (K.C. Jacobson & Crockett, 2000). Thus, the fact that parents monitor daughters more closely than sons may contribute to gender differences in aggression. C O M P A R I N G G I R L S A N D B O Y S n 631 peer influences Gender differences in aggression are consistent with the gen- der-typed social norms of girls’ and boys’ same-gender peer groups. However, it is worth noting that children who are high in aggression and low in prosocial behav- ior are typically rejected in both male and female peer groups (P. H. Hawley, Little, & Card, 2008). These children tend to seek out marginal peer groups of other simi- larly rejected peers, and these contacts strengthen the likelihood of physical aggres- sion over time (N. E. Werner & Crick, 2004). Another peer influence on aggression may be boys’ regular participation in aggressive contact sports, which sanction the use of physical force and may contrib- ute to higher rates of direct aggression among boys (Messner, 1998). Support for this proposal is the finding that participation in aggressive sports, such as football, in high school is correlated with a higher likelihood of sexual aggression in college (G. B. Forbes et al., 2006). As explained in Box 15.6, aggressive behaviors may also involve sexual harassment. Media influences A common question for parents and researchers is whether frequently watching violent TV shows and movies or playing violent video games has a negative impact on children. As you might expect, boys are more likely than Sexual harassment commonly affects both boys and girls and can involve direct (physi- cal or verbal) or indirect (relational) aggres- sion. Physical sexual harassment involves inappropriate touching or forced sexual activity. Verbal sexual harassment involves unwanted, demeaning, or homophobic sex- ual comments, whether spoken directly to the target or indirectly, behind her or his back. Also, verbal harassment commonly spreads via electronic media (Ybarra & Mitchell, 2007). Surveys in the United States and Canada indicate that the vast majority of both girls and boys have experienced sexual harass- ment during adolescence (American Associ- ation of University Women, 2011; Leaper & Brown, 2008; McMaster et al., 2002). Most teen sexual harassment occurs in school hallways and classrooms, and the perpetra- tors are more likely to be peers rather than teachers or other adults. In an American As- sociation of University Women (AAUW) sur- vey (2011), 56% of girls and 40% of boys in middle and high school reported hav- ing experienced sexual harassment at least once during the prior year. Other surveys suggest that rates of sexual harassment may be higher for sexual-minority (lesbian, gay, bisexual, transgender, and intersex) youths (Williams et al., 2005). Studies indicate that sexual harassment is also a problem for teens in many parts of the world (see Leaper & Robnett, 2011). Two of the most frequent forms of reported sexual harassment in the AAUW survey were unwanted sexual comments or gestures (46% of girls, 22% of boys) and being called gay or lesbian in a negative way (18% of girls, 19% of boys). When the ado- lescents were asked to indicate whether and how sexual harassment affected them, girls were more likely than boys to report nega- tive effects. The most common responses to sexual harassment included not wanting to go to school (37% of girls, 25% of boys) and finding it difficult to study (34% of girls, 24% of boys). Boys were more likely than girls to report that experiences with sexual harassment had no effect on them (17% of boys, 10% of girls). Girls may tend to have more negative re- actions to sexual harassment than do boys partly because girls are somewhat more likely than boys to experience repeated sex- ual harassment. Also, because of traditional masculine socialization, boys may be more reluctant to admit vulnerability. Regard- less of the individual’s gender, repeated experiences with sexual harassment can have long-term negative consequences on girls’ and boys’ self-esteem and adjustment (S. E. Goldstein et al., 2007; Gruber & Fineran, 2008). Sexual harassment and violence also occur in dating relationships. Physical aggression occurs in an estimated one- fourth of adolescent heterosexual dating relationships (Hickman, Jaycox, & Aronoff, 2004; O’Leary et al., 2008), with boys being more likely to be the perpetrators (Swahn et al., 2008; Wolitzky-Taylor et al., 2008). As a consequence, many girls come to regard demeaning behaviors as normal in hetero- sexual relationships (Witkowska & Gådin, 2005), and they therefore may be at risk for dysfunctional and abusive relationships in adulthood (Larkin & Popaleni, 1994). Although there have been fewer studies of dating violence in lesbian and gay teens’ re- lationships, one survey indicated that the prevalence of dating violence among sexual- minority youths was similar to that among heterosexual youths (Freedner et al., 2002). BOX 15.6: applications SEXUAL HARASSMENT AND DATING VIOLENCE 632 n chApter 15 GENDER DEVELOPMENT girls to devote time to these activities (Cherney & London, 2006). One possible inference is that consuming more violent media may contribute to average gender differences in physical aggression. Our discussion of media violence in Chapter 9 makes clear that viewing aggres- sion in movies, TV programming, and video games is associated with children’s aggressive behavior and that this holds true for girls as well as for boys. Several experimental studies point to a causal influence. That is, the likelihood of aggres- sion increases in some children after watching violent programs (Paik & Com- stock, 1994) or playing violent videogames (Ferguson, 2007). Exposure to violent media may lead to increased arousal and decreased inhibition, which may stimulate aggression in some children (Coyne & Archer, 2005). However, rather than caus- ing aggression, the effect might more likely be correlated with children who are also prone toward aggressive behavior for additional reasons. Whereas boys are more likely than girls to favor TV shows and movies with vio- lent content, one study found that adolescent girls were more likely than boys to prefer shows depicting indirect aggression (Coyne & Archer, 2005). Furthermore, an experimental study demonstrated that observing indirect aggression on TV increased the subsequent likelihood of indirect aggressive behavior but had no impact on direct aggression (Coyne, Archer, & Eslea, 2004). Other cultural influences Although gender differences in aggression have been observed in all cultures, cultural norms also play an important role in determin- ing the levels of aggression that are observed in boys and girls. Douglas Fry (1988) studied rural communities in the mountains of Mexico and found that the levels of childhood aggression that were considered normal varied widely from one area to another. Boys in each community showed more aggression than girls did. How- ever, girls in the high-aggression communities were more aggressive than boys in the low-aggression communities. The community context must also be considered in relation to the emergence of differential rates of aggression among U.S. youth. Levels of violence are high in many U.S. communities, particularly in inner-city areas where an estimated 40% to 60% rates of violence are high in many U.S. communities, and boys are more likely to witness violent events. these experiences may contribute to higher rates of aggression for boys compared with girls. KA T H LE E N F LY N N / T H E T IM E S -P IC AY U N E / L A N D O V C H A P T E R S U M M A R Y n 633 of children have witnessed violent crimes within the previous year (Osofsky, 1995). When children are exposed to violence in their homes and communities, boys and girls both experience an increased risk of emotional and behavioral problems and show an increase in aggressive behaviors. However, boys are more likely than girls to be exposed to the highest levels of violence, and the average impact of exposure is also greater for boys than for girls (Guerra, Huesmann, & Spindler, 2003). review: Gender development begins before birth when the genes program the developing embryo to form female or male genitalia. In the absence of androgen hormones triggered by the Y chro- mosome, female genitalia form. The higher production of androgens in genetic males (and, in rare cases, in genetic females) may influence brain organization and functioning. Physi- cal changes during puberty typically lead to increased muscle mass in boys as well as large average advantages in strength, speed, and size. Also, puberty leads to bodily transformations that allow for each sex’s reproductive ability. Although the common impression is that girls and boys are inherently and deeply different in their cognitive and social behaviors, in most respects the similarities between them out- weigh the differences. As summarized in Table 15.1, even when differences are consistently reported, they tend to be fairly small. Also, many average differences do not emerge until later in childhood or adolescence. The most substantial differences are found in physical strength and speed, specific spatial abilities (e.g., mental rotation), academic achievement, self-regulation, activity level, and physical aggression. Small average gender differences are seen in verbal ability, risk taking, interpersonal goals, and communication style. A combina- tion of biological, cognitive-motivational, and cultural influences are implicated to varying degrees in most of these differences. chapter summary: Theoretical Approaches to Gender Development n One major approach to gender development is biological, including evolutionary psychology, biosocial theory, and neuro science approaches. n According to evolutionary psychology theory, behavioral differ- ences between males and females served adaptive functions in our evolutionary past and have been passed down as inherited behavioral dispositions. For example, direct aggression in males is interpreted as an advantage in mating competition, whereas nurturance in females is viewed as facilitating the survival of offspring. n Biosocial theory focuses on the impact of evolved physical differ- ences between females (childbearing and nursing capacities) and males (greater strength, speed, and size) in relation to the social ecology. For example, men’s strength and women’s childbearing may have made certain roles more appropriate for women and men in hunter-gatherer societies, but physical differences impose fewer constraints on roles in technological societies. n Other biological researchers take a neuroscience approach to gender development by focusing on sex differences in brain organization and the influences of sex hormones (such as andro- gens) both before birth and after. A striking example of hor- monal influence involves cases of girls with congenital adrenal hyperplasia (CAH), who tend to show a stronger inclination toward play emphasizing physical activity and tend to perform somewhat better on spatial abilities than do girls without CAH. n A second approach, which addresses cognitive and motiva- tional influences on gender development, includes cognitive developmental theory, gender schema theory, social identity theory, and social cognitive theory. All emphasize children’s active participation in learning gender roles and adopting the preferences and behaviors considered appropriate for their gender, thereby highlighting how gender development is largely a process of self-socialization. n According to cognitive developmental theory, once children realize that their gender is consistent across situations (gender constancy), they pay close attention to same-gender models to learn how to behave. n Gender schema theory maintains that children con- struct mental representations of gender based on their own 634 n chApter 15 GENDER DEVELOPMENT experience and the gender-related ideas they are exposed to and proposes that children begin to acquire same-gender inter- ests and values as soon as they can identify their own gender. Subsequently, children pay greater attention to, and learn more about, those things that they regard as relevant for their own gender. n Social identity theory, which also stresses the importance of adopting a gender identity, proposes that children tend to form an ingroup bias favoring attributes associated with their own gender and also to enforce conformity to gender-role norms. n Social cognitive theory addresses many processes involved in learning gender-typed values and behaviors, including observing others’ behavior and determining the consequences of particular behaviors in relation to one’s own or other peo- ple’s gender. Children internalize gender-typed norms, stan- dards that they use to monitor their own behavior. n The third theoretical approach focuses on cultural influences and includes the bioecological model and social role theory. The bioecological model characterizes children’s develop- ment as embedded in nested systems ranging from the micro- system (immediate environment) to the macrosystem (society). A key feature of the macrosystem is its opportunity struc- ture and the corresponding roles available to women and men that shape the ways in which girls and boys are socialized. Social role theory similarly addresses the division of labor by gender in society and how it affects girls’ and boys’ gender-role development. Milestones in Gender Development n Between 6 and 8 weeks of prenatal development, sexual differ- entiation begins. External and internal genitalia are normally completed by the end of the first trimester. n During their first year, infants learn to distinguish male and female faces. Between ages 2 and 3, children learn to iden- tify their own gender, start to acquire stereotypes about males and females, and begin to prefer gender-typed toys and play activities. n During preschool, children begin to gravitate toward same- gender peers, and a strong tendency for children to self- segregate by gender persists until adolescence. Preschool children also stereotype certain traits and activities for each gender. Preferences for gender-typed play become stronger from early to middle childhood. n Around 6 years of age, children develop gender constancy. In addition, during middle childhood, they come to understand that gender roles are social conventions. They also may under- stand that gender discrimination is unfair and notice when it occurs. Average gender differences in social behavior begin to emerge, with boys more likely than girls to stress assertion over affiliation, and girls more apt to emphasize affiliation or a combination of affiliation and assertion. n During adolescence, gender roles sometimes become more flexible (due to increased cognitive flexibility) or more rigid (due to concerns with heterosexual roles and adoption of conventional gender attitudes). Intimacy in friendships and romantic relationships also increases for both girls and boys, although friendship intimacy is more common among girls. n Throughout childhood and adolescence, gender-role flexibility is more likely among girls than among boys. Peers and parents tend to react more negatively to cross-gender-typed behavior in boys than in girls. This asymmetry may be related to the higher status and power traditionally accorded males. Comparing Girls and Boys n Actual differences in girls’ and boys’ psychological functioning are decidedly fewer than commonly portrayed by gender ste- reotypes. Even on measures in which, on average, one gender scores higher than the other, the effect size often is trivial for many attributes. Moreover, considerable overlap usually occurs in the distribution of scores for males and females even when gender differences in effect size are greater. n Boys and girls are quite similar in physical development until puberty, which begins earlier for girls than for boys. Among the largest average gender differences are physical strength, speed, and size after puberty, and a moderate difference exists in physical activity level. n Girls and boys score similarly on tests of general intelli- gence. Slight-to-small average gender differences have been reported in specific cognitive abilities: boys show higher profi- ciency with certain types of spatial reasoning and mathematic ability, and girls show a small advantage in verbal ability. In academic achievement, girls have tended to do better than boys in reading and writing, whereas boys have tended to do better than girls in the physical sciences. Girls also tend to do better in overall school performance. n Biological, cognitive-motivational, and cultural factors may contribute to gender-related variations in academic achieve- ment. Biological processes, such as prenatal hormones, may influence girls’ and boys’ brain development; however, the degree to which these factors lead to gender differences in cognitive functioning is unclear. The evidence for cognitive- motivational and cultural influences on average gender dif- ferences in academic achievement is more clearly established. Researchers find academic achievement in particular domains is related to the expectations of parents, peers, and teachers. The gender gap in U.S. math achievement has dramatically closed in recent decades, and such differences are less likely in societies characterized by greater overall gender equality. n Average gender differences in personality are seen in self- regulation (girls higher), physical activity (boys higher), and risk taking (boys higher). Biological factors, such as prenatal androgen levels, may be related in part to later gender differ- ences in some or all these personality traits. However, tradi- tional socialization may exaggerate gender differences. n Direct (physical and verbal) aggression is associated with an average gender difference of moderate effect size, with higher C H A P T E R S U M M A R Y n 635 rates among boys than among girls. No meaningful average gender difference appears in indirect aggression (such as social exclusion or negative gossip). However, indirect aggression con- stitutes a larger proportion of all aggressive behaviors among girls than among boys. Lower average levels of self-regulation may be partly related to the higher incidence of direct aggression among boys. Cognitive and motivational factors are important as well. For example, boys often practice aggressive themes and behav- iors in their play, and aggression is tolerated more in boys than in girls. Some cultural variations in the magnitude of gender differ- ence in direct aggression are related to the degree that behaviors such as sexual harassment are tolerated in a particular culture. Critical Thinking Questions 1. The two children pictured at the start of the chapter display gender-typed differences in their behavior and interests. How would the different theories outlined in this chapter attempt to explain these differences and similarities? How would different theories account for other children who have more flexible gender-typed behaviors and interests? 2. Think about how females and males were portrayed in televi- sion shows, movies, and video games as you were growing up. How might these depictions have affected your gender development? 3. Imagine that you wanted to raise your own children to be as minimally gender-typed as possible. Which of the theoretical perspectives outlined in the chapter would you rely on most? Do you think you would be more likely to achieve your goal with a daughter or a son? 4. Suppose you are speaking with an evolutionary psychology theorist who tells you that biology makes gender differences in behavior inevitable. What evidence could you use to challenge this view? What evidence could you use to sup- port it? 5. Historically, men have held dominant status in society, but in the last century, women have significantly increased their status and power in the United States and in many other countries. Women now occupy top ranks in many occupations, and men are more involved in child-care and housework. Do you think that this trend toward gender equality among adults will affect the kinds of play activities and behaviors in which girls and boys engage in the future? Key Terms activating influences, p. 598 adrenarche, p. 619 affiliation, p. 594 androgen insensitivity syndrome (AIS), p. 599 androgens, p. 598 assertion, p. 594 body image, p. 618 collaboration, p. 594 congenital adrenal hyperplasia (CAH), p. 599 cross-gender-typed, p. 595 effect size, p. 615 enactive experience, p. 604 gender constancy, p. 600 gender dysphoria disorder, p. 598 gender identity, p. 600 gender schema filter, p. 602 gender schemas, p. 601 gender segregation, p. 609 gender stability, p. 600 gender typing, p. 595 gender-essentialist statements, p. 604 gender-role flexibility, p. 612 gender-role intensification, p. 612 gender-typed, p. 595 ingroup assimilation, p. 603 ingroup bias, p. 603 interest filter, p. 602 menarche, p. 618 meta-analysis, p. 615 observational learning, p. 604 opportunity structure, p. 606 organizing influences, p. 598 puberty, p. 618 self-socialization, p. 599 spermarche, p. 618 transgender, p. 599 tuition, p. 603 636 L I N C O L N S E L I G M A N , Kite Flying, 2000 P R IV AT E C O LL E C T IO N / T H E B R ID G E M A N A R T L IB R A R Y 637 chapter 16: Conclusions n Theme 1: Nature and Nurture: All Interactions, All the Time Nature and Nurture Begin Interacting Before Birth Infants’ Nature Elicits Nurture Timing Matters Nature Does Not Reveal Itself All at Once Everything Influences Everything n Theme 2: Children Play Active Roles in Their Own Development Self-Initiated Activity Active Interpretation of Experience Self-Regulation Eliciting Reactions from Other People n Theme 3: Development Is Both Continuous and Discontinuous Continuity/Discontinuity of Individual Differences Continuity/Discontinuity of Overall Development: The Question of Stages n Theme 4: Mechanisms of Developmental Change Biological Change Mechanisms Behavioral Change Mechanisms Cognitive Change Mechanisms Change Mechanisms Work Together n Theme 5: The Sociocultural Context Shapes Development Growing Up in Societies with Different Practices and Values Growing Up in Different Times and Places Growing Up in Different Circumstances Within a Society n Theme 6: Individual Differences Breadth of Individual Differences at a Given Time Stability Over Time Predicting Future Individual Differences on Other Dimensions Determinants of Individual Differences n Theme 7: Child-Development Research Can Improve Children’s Lives Implications for Parenting Implications for Education Implications for Helping Children at Risk Improving Social Policy 638 I n the preceding 15 chapters, you were presented with a great deal of information about how children develop. You learned about the development of perception, attachment, conceptual understanding, language, intelligence, emotional regula- tion, peer relations, aggression, morality, gender, and a host of other vital human characteristics. Although these are all important parts of child development, the sheer amount of information may seem daunting: getting lost in the trees and los- ing a sense of the forest is a real danger. We therefore devote this final chapter to providing an overview of the forest by organizing many of the specifics that you have learned into an integrative framework. A likely side benefit of reading this chapter is that you will probably discover that you understand much more about child development than you realized. The integrative framework that organizes this chapter consists of the seven themes that were introduced in Chapter 1 and highlighted throughout the book. As we have noted, most child-development research is ultimately aimed at understanding fundamental issues related to these themes. This is true regardless of the type of development that the research addresses and regardless of whether the research focuses on fetuses, infants, toddlers, preschoolers, school-age children, or adolescents. Beneath the myriad details, the seven themes emerge again and again. Theme 1: Nature and Nurture: All Interactions, All the Time When people think of a child’s nature, they typically focus on the biological char- acteristics with which the child enters the world. When they think of the child’s nurture, they focus on the child-rearing experiences provided by parents, care- givers, and other adults. Within this view, nurture is like a sculptor, shaping the raw material provided by the child’s nature into closer and closer approximations of its final form. Although this metaphor is appealing, the reality is much more complex. Unlike the sculptor’s passive media of marble and clay, children are active partici- pants in their own development. They seek out their own experiences, based on their inclinations and interests. They also influence other people’s behavior toward them: from birth onward, their nature influences the nurture they receive. In addition, rather than nature doing its work before birth and nurture doing its work after, nurture influences development even before birth, and nature is just as influential in adolescence and adulthood as earlier. In this section, we review how nature and nurture interact to produce development. Nature and Nurture Begin Interacting Before Birth When prenatal development proceeds normally, it is easy to think of it as a simple unfolding of innate potential, one in which the environment matters little. When things go wrong, however, the interaction of nature and nurture is all too evident. Consider the effects of teratogens. Prenatal exposure to these potentially harmful substances—which include toxins in the general environment, such as mercury, radiation, and air pollution, as well as toxins that depend on parental behavior, such as cigarettes, alcohol, and illegal drugs—can cause a wide variety of physical and cognitive impairments. However, whether a given baby will actually be affected Themes n Nature and Nurture n The Active Child n Continuity/Discontinuity n Mechanisms of Change n The Sociocultural Context n Individual Differences n Research and Children’s Welfare T H E M E 1 : N A T u R E A N D N u R T u R E : A L L I N T E R A C T I O N s , A L L T H E T I M E n 639 depends on innumerable interactions among the genetics of the mother, the genet- ics of the fetus, and a host of environmental factors such as the particular teratogen and the timing and amount of exposure. The interaction of nature and nurture during the prenatal period is also evi- dent in fetal learning. The experience of hearing their mother’s voice while in the womb leads newborns to prefer her voice to that of other women once they enter the world. Fetuses can also learn taste preferences from their mother’s diet during pregnancy. Thus, even qualities that are present at birth, which are often thought of as being determined purely by nature, reflect the fetus’s experience as well. Infants’ Nature Elicits Nurture Nature equips babies with a host of qualities that elicit appropriate nurture from parents and other caregivers. One big factor in babies’ favor is that they are cute; most people enjoy watching and interacting with them. Their looking and smiling at other people mo- tivates others to feel warmly toward them and to care for them. Their emotional expressions—cries, coos, and smiles—guide caregivers’ efforts to figure out what to do to make them happy and comfortable. In addition, their attentiveness to sights and sounds that they find interesting encourages others to talk to them and to provide the stimulation necessary for learning. One simple example of this interactive relationship is the fact that parents everywhere sing to their infants; infants throughout the world find singing soothing, bounce in response to rhythm, and respond positively to melodies. Timing Matters The effects of an experience on development depend on the state of the organism at the time of the experience. As already noted, timing of exposure to teratogens greatly influences their effects on prenatal development. For example, if a pregnant woman comes down with rubella early in pregnancy, when the developing visual and auditory systems are at a particularly sensitive point, her baby may be born deaf or blind; if she comes down with rubella later in pregnancy, no damage will occur. Timing also influences many aspects of development in the months and years following birth. The development of perceptual capabilities presents numerous illustrations of the importance of appropriate experience at the appropriate time. The general rule in such cases is “use it or lose it”: for normal development to occur, children must encounter the relevant experiences during a certain window of time. Auditory development provides a good example. Until 8 months of age, infants can discriminate between phonemes regardless of whether they occur in the lan- guage the infants hear daily. By age 12 months, however, infants lose the ability to hear the difference between similar sounds that they do not ordinarily encounter or that are not meaningfully different in their native language. Similar sensitive periods occur in grammatical development. Children from East Asia who move to the United States and begin to learn English as a second Infants’ expressions of contentment and happiness when engaging in certain activi- ties motivate their parents and other adults to engage in the activities with them. E M M A N u E L FA u R E / G E T T Y I M A G E s 640 n chapter 16 CONCLusIONs language before age 7 acquire grammatical competence in English that eventually matches that of native-born American children. Those who arrive between ages 7 and 11 learn almost as well. However, individuals who immigrate at later ages rarely gain comparable mastery of English grammar, even after many years of hearing and speaking the language of their adopted land. Deaf children’s learning of American Sign Language shows a similar pattern: early exposure results in more complete grammatical mastery. The importance of normal early experience is also evident in social, emotional, and intellectual development. Infants and toddlers who do not have an emotional connection with any caregiver, such as the children who spent their first years in the infamous orphanages of Romania in the 1980s or in concentration camps dur- ing World War II, often continue to interact abnormally with other people after being placed in loving homes. Those who spent their first two years or more in the Romanian orphanages also had unusually high rates of low IQ for many years after they were adopted into loving homes in Great Britain. Thus, in many aspects of the development of perception, language, intelligence, emotions, and social behavior, the timing of experience is crucial: normal early experience is vital for successful later development. Nature Does Not Reveal Itself All at Once Many genetically influenced properties do not become evident until middle child- hood, adolescence, or adulthood. One obvious example is the physical changes that occur at puberty. A less obvious example involves nearsightedness. Many children are born with genes that predispose them to become nearsighted, but most do not become so until late childhood or early adolescence. The more close work, includ- ing reading, they do during childhood, the more likely that the genetic predisposition will eventually be realized. A third example involves children who are born with certain types of brain damage. These chil- dren’s performance on IQ tests is comparable to that of other children through age 6 years, but falls considerably behind thereafter. The development of schizophrenia follows a similar path. Schizo- phrenia is highly influenced by genes inherited at conception, but most people who become schizophrenic do not do so until late adolescence or early adulthood. As with other aspects of development, the emer- gence of schizophrenia reflects a complex interplay between nature and nurture. Children with a schizophrenic biological parent who are raised by nonschizophrenic parents are more likely to become schizophrenic themselves than are the biological children of the nonschizophrenic par- ents. Children who are raised in troubled homes are also more likely than others to become schizophrenic. However, the only children with a substantial likelihood of becoming schizophrenic are those who have a biological parent who is schizophrenic and who also grew up in a trou- bled family. As in other contexts, the interaction between the children’s nature and the nurture they receive is crucial. Perhaps the most surprising and compelling evidence for the interaction of nature and nurture comes from the emerging field of epigenetics. Although people often think of the genotype as being “fixed” at birth, experience can enhance or silence gene expression. Early stressful environments, such as those imposed by poverty, seem to especially influence later gene expression. Thus, adults who grew Differences in running speeds are partially attributable to genetic differences that are present at birth, but nature takes time to reveal itself. Who could have looked at these children when they were newborns and pre- dicted which would be the best runners? P O LK A D O T I M A G E s / T H IN K s T O C K T H E M E 2 : C H I L D R E N P L A Y A C T I V E R O L E s I N T H E I R O w N D E V E L O P M E N T n 641 up in low-income families exhibit different patterns of gene expression decades later than do adults who grew up in high-income homes, regardless of their incomes as adults. Even more remarkably, some of these effects of the early environment on the genome are passed down to the next generation. Thus, not only does nature not reveal itself all at once, but nature itself changes as a result of nurture. Everything Influences Everything One common reaction to learning about the complex interactions between nature and nurture is “It sounds like everything influences everything else.” This reaction is basically accurate. Consider some of the factors that influence children’s and ado- lescents’ self-esteem. Genes matter; the closer the biological relation between two children or adolescents, the more similar their degree of self-esteem is likely to be. A large part of the reason for this genetic influence on self-esteem is that genes influence a wide range of other characteristics that themselves influence self-esteem. For example, genes strongly affect attractiveness, athletic talent, and academic suc- cess, all of which contribute to self-esteem. Factors other than genes also play large roles in the development of self-esteem. Support from one’s family and peers contribute in a positive way; poverty and unpopularity contribute in a negative way. Unrelated adults also can have positive or negative influences on self-esteem; for example, having a teacher who is support- ive can promote a child’s self-esteem; conversely, having a teacher who is hostile or demeaning can reduce it. Values of the broader society also are influential. East Asian societies tend to emphasize the importance of self-criticism, and children and adolescents in those societies report lower levels of self-esteem than do peers in Western societies. Complex interactions are not limited to the development of self-esteem or to social development; they are characteristic of development in all areas. For example, in the development of intelligence, the influence of genetics seems to be greater than that of shared environment for children from middle- and upper-income backgrounds, but the opposite is true for children from impoverished backgrounds. Similarly, parental involvement in school is more closely related to academic achievement in low-income families than in more affluent families. Thus, children’s nature—their genes, personal characteristics, and behavioral tendencies—interact with the nurture they receive from parents, teachers, peers, the broader society, and the physical environment in ways that shape their self-esteem, intellect, and other qualities. Theme 2: Children Play Active Roles in Their Own Development Children are physically active even before they leave the womb; the fetal kicking that thrills prospective parents is just the most obvious example. Less obvious is that fetuses are also mentally active. While still in the womb, they can learn enough about the sounds in a story their mother repeatedly reads aloud that, as newborns, they are able to discriminate that story from ones their mother did not read aloud. Moreover, from their first minutes outside the womb, infants selectively focus on objects and events that interest them, rather than passively gazing at whatever appears before their eyes. 642 n chapter 16 CONCLusIONs Infants’ and older children’s actions also produce reactions in other people, which further shape the children’s development. In this section, we examine four ways in which children contribute to their own development—through physically interact- ing with the environment, interpreting their experience, regulating their behavior, and eliciting reactions from other people. Self-Initiated Activity Even in the womb, normal development depends on the fetus’s being active. Fetuses make breathing movements that strengthen their lungs, and they swallow amniotic fluid that prepares their digestive system to function properly after birth. They also “work out” various muscles by tugging on their umbilical cord, sucking their thumb, kicking, and turning somersaults. From the day they are born, infants display looking prefer- ences that guide their attention to the most informative as- pects of the environment that their processing abilities can handle and thus enhance their learning. They like looking at objects rather than at blank fields. They like looking at moving objects rather than at stationary ones and at the edges of objects rather than at their interiors. And they particularly like looking at faces, especially their mother’s. Infants’ ability to interact with the environment expands greatly during the first year. At around 3 months, most infants become able to follow moving objects fairly smoothly with their eyes, which improves their ability to learn about the actions occurring around them. At 6 or 7 months, most become able to crawl on their bellies, and soon after on their hands and knees; as a result, they no longer have to wait for the world to come to them. By 8 or 9 months, most can hold up their heads, which allows them to reach accurately for objects even when they are not being sup- ported. And by 13 or 14 months, most begin to walk independently, opening new frontiers for exploration. As development proceeds, children’s self-initiated activity extends to additional domains such as language. Toddlers delight in telling their parents the names of objects, for no reason beyond the joy of doing so. They practice talking in their cribs, even when nobody else is present to hear them. They and older children, both deaf and hearing, invent gestures and words to represent objects and events. As their language proficiency develops, children become skilled at initiating conversations that bring them in- formation, allow them to express their feelings and desires, and help them regulate their emotions. The effects of self-initiated activities also are seen at older ages in other areas, such as self-socialization and antisocial behavior. Throughout the world, boys and girls choose to play predominantly with members of their own gender, especially between the ages of 6 and 10 years. The play patterns reflect the children’s own choices: gender segregation is rarely imposed by adults but, rather, arises from differences in the kinds of play that boys and girls tend to prefer. Beginning in the school years, these preferences tend to be reinforced by ridicule from peers when a child crosses the “gender border.” as this infant’s eager gaze suggests, chil- dren’s choices of where to look are among the ways in which they shape their own development. C O u R T E s Y O F R O B E R T s IE G LE R children’s choices of activities shape their development. this child’s interest in print led him to learn to read and write at age 3; the fact that he is one of the authors’ chil- dren also probably had something to do with his early interest in these skills. (he also is now the father of the baby in the photo above.) C O u R T E s Y O F A LI C E & R O B E R T s IE G LE R T H E M E 2 : C H I L D R E N P L A Y A C T I V E R O L E s I N T H E I R O w N D E V E L O P M E N T n 643 In later childhood and adolescence, children’s choices of friends and peer groups become important influences on their own behavior, in that children tend to increasingly act like their friends and others in their social group in both positive and negative ways. Thus, from the prenatal period through adolescence, children’s self-initiated activities contribute to their development. Active Interpretation of Experience Children also contribute to their development by trying to understand the world around them. Even in the first year, infants develop a sense of what is possible in the physical world. Thus, they look longer at an “impossible” event—such as when one solid object appears to move through the space occupied by another object, or when an object seems to be suspended in midair without support—than they do at an event that is similar but physically possible. Toddlers’ and preschoolers’ continuous “why” questions, and school-age children’s searching for the explana- tions of magic tricks, provide other compelling examples of children’s eagerness to understand the world. This desire to understand also motivates young children to construct informal theories concerning inanimate objects, living things, and people. These theories allow children to go beyond the data provided by their senses to infer under lying causes. For example, preschoolers reason that there must be something inside animals that causes them to grow, breathe, have babies, get sick, and so on, even though they do not know what that something is. They also reason that inani- mate objects must have different material inside them than living things do. Children’s and adolescents’ interpretation of their experiences extends to infer- ences about themselves as well as about the external world. When some children fail on a task, for example, they feel sad and question their ability. Other children who fail on the same task take the failure as a challenge and an opportunity to learn. Similarly, in ambiguous situations, aggressive children tend to attribute hos- tile intentions to others even when the others’ motives are unclear; this interpre- tation sometimes leads the aggressive children to lash out before the other person can hurt them. Thus, subjective interpretations of experiences, as well as objective reality, shape development. Self-Regulation Another way in which children contribute to their development is by regulating their behavior. Consider how they regulate their emotions. In the first months after they are born, infants rely almost totally on parents and other caregivers to help them cope with fright and frustration. By age 6 months, they learn to cope with some upsetting situations by rubbing their bodies to soothe themselves. During the toddler and preschool periods, children become increasingly adept at using physi- cal strategies, such as looking away, when faced with stressors or temptation. Dur- ing elementary school, they increasingly use cognitive strategies, such as reminding themselves that an unpleasant experience will soon be over, to cope with negative situations. Across a wide range of ages, children who successfully regulate their emotions tend to be more popular and more socially competent than those who are less skilled at emotional regulation. These early self-regulation skills are related to long-term developmental out- comes. For example, boys who exhibit strong self-regulation abilities in the pre- school and early elementary school periods are less likely as adults to use cocaine 644 n chapter 16 CONCLusIONs and other drugs. Children’s early self-control also has been found to be a strong predictor of their later grades in school and of occupational and economic success in adulthood. Over the course of childhood and adolescence, children increasingly regulate their development through their choice of activities. Whether young children go to sports events, movies, libraries, or religious services depends mainly on whether their parents take them there. Whether adolescents engage in the same activi- ties depends mainly on their own preferences. Selecting moral values, choosing a romantic partner, pursuing an occupation, and deciding whether to have children are just a few of the major decisions that adolescents and young adults face. The wisdom of their choices strongly influences their subsequent lives. Eliciting Reactions from Other People Because children of all ages differ from one another in behavior and appearance, they evoke different reactions from other people. For example, babies with easy temperaments elicit more positive reactions from their parents than do cranky or fussy babies. Similarly, attractive babies elicit more affectionate and playful moth- ering than do less attractive ones. And in trying times, attractive children are less likely to suffer parental rejection and punishment than are less attractive ones. Other adults also are influenced by children’s actions. For example, when children encounter difficulty learning particular material, teachers act in more encouraging ways if the child has generally been well behaved than if the child has been badly behaved in the past. The effects that children’s initial inclinations have on their parents’ behavior toward them multiply over time. Most parents of children who are disobedient, angry, and challenging try to be supportive but firm with them. However, if the bad behavior and defiance continue, many parents become hostile and punitive. Other parents, faced with belligerence and aggression, back down from confrontations and increasingly give in to their children’s demands. Once such negative cycles are established, they are difficult to stop. If teenagers act disruptively, and parents respond with hostility, problems generally worsen over the course of adolescence. Children’s characteristics and behavior influence not just their parents’ and teachers’ reactions but also those of their peers. At all ages, children who are cooperative, friendly, sociable, and sensitive to others tend to be popular with their peers, whereas those who are aggressive or disruptive tend to be disliked and rejected. In some cases, peers’ reactions to one another’s behavior change with age; for example, kindergartners tend to neither like nor dislike withdrawn peers, but older elementary and middle school students tend to dislike such children. Peer reactions to children’s behavior often have long-term consequences; rejected children are more likely than popular children to have dif- ficulty later in school and to engage in criminal activity. In many ways, then, chil- dren influence their development, not only by initiating actions, interpreting their experiences, and regulating their emotions, but also by eliciting reactions from other people that then shape their own subsequent behavior. It is all too easy for relations between par- ents and children to spiral downward, with disobedience and anger from children elic- iting anger and hostility from parents, which then elicits more disobedience and anger from children, and so on. M A R Y K AT E D E N N Y / P H O T O E D IT T H E M E 3 : D E V E L O P M E N T I s B O T H C O N T I N u O u s A N D D I s C O N T I N u O u s n 645 Theme 3: Development Is Both Continuous and Discontinuous Long before there was a scientific discipline of child development, philosophers and others interested in human nature argued about whether development is continu- ous or discontinuous. Current disputes between those who believe that development is continuous, such as social learning theorists, and those who believe it is discon- tinuous, such as stage theorists, thus have a long history. There is good reason why both positions have endured so long: each captures important truths about develop- ment, and neither captures the whole truth. Two particularly important issues in this longstanding debate involve continuity/discontinuity of individual differences and continuity/discontinuity of the standard course of development with age. Continuity/Discontinuity of Individual Differences One sense of continuity/discontinuity involves stability of individual differences over time. The basic question is whether children who initially are higher or lower than most peers in some quality continue to be higher or lower in that quality years later. It turns out that many individual differences in psychological properties are moderately stable over the course of development, but the stability is always far from 100%. Consider the development of intelligence. Some stability is present from infancy onward. For example, the faster that infants habituate to repeated presentation of the same display, the higher their IQ scores tend to be 10 or more years later. Infants’ patterns of electrical brain activity also are related to their speed of pro- cessing and attention regulation more than 10 years later. The amount of stability increases with age. IQ scores show some stability from age 3 to age 13, consider- able stability from age 5 to age 15, and substantial stability from age 8 to age 18. Even in older children, however, IQ scores vary from occasion to occasion. For example, when the same children take IQ tests at ages 8 and 17, the two scores dif- fer on average by 9 points. Part of this variability reflects random fluctuations in how sharp the person is on the day of testing and in the person’s knowledge of the particular questions on each test. Another part of the variability reflects the fact that even if two children start out with equal intelligence, one may show greater intellectual growth over time. Individual differences in social and personality characteristics also show some continuity over time. Shy toddlers tend to grow into shy children, fearful toddlers into fearful children, aggressive children into aggressive adolescents, generous chil- dren into generous adults, and so on. The continuity also carries over into situations quite different from any that the children faced at the earlier time; for example, se- cure attachments in infancy predict positive romantic relationships in adolescence. Although there is some continuity of individual differences in social, emotional, and personality development, the degree of continuity is generally lower than in intellectual development. For example, whereas children who are high in read- ing and math achievement in 5th grade generally remain so in 7th grade, children who are popular in 5th grade may or may not be popular in 7th grade. In addition, aspects of temperament such as fearfulness and shyness often change considerably over the course of early and middle childhood. Regardless of whether the focus is on intellectual, social, or emotional devel- opment, the stability of individual differences is influenced by the stability of the environment. For instance, an infant’s attachment to his or her mother correlates 646 n chapter 16 CONCLusIONs positively with the infant’s long-term security, but the correlation is higher if the home environment stays consistent than if serious disruptions occur. Similarly, IQ scores are more stable if the home environment remains stable. Thus, continuities in individual differences reflect continuities in children’s environments as well as in their genes. Continuity/Discontinuity of Overall Development: The Question of Stages Many of the most prominent theories of development divide childhood and adoles- cence into a small number of discrete stages. Piaget’s theory of cognitive develop- ment, Freud’s theory of psychosexual development, Erikson’s theory of psychosocial development, and Kohlberg’s theory of moral development all describe development in this way. The enduring popularity of these stage approaches is easy to understand: they simplify the enormously complicated process of development by dividing it into a few distinct periods; they point to important characteristics of behavior during each period; and they impart an overall sense of coherence to the developmental process. Although stage theories differ in their particulars, they share four key assump- tions: (1) development progresses through a series of qualitatively distinct stages; (2) when children are in a given stage, a fairly broad range of their thinking and behavior exhibits the features characteristic of that stage; (3) the stages occur in the same order for all children; and (4) transitions between stages occur quickly. Development turns out to be considerably less tidy than stage approaches imply, however. Children who exhibit preoperational reasoning on some tasks often exhibit concrete operational reasoning on others; children who reason in a preconven- tional way about some moral dilemmas often reason in a conventional way about oth- ers; and so on. Rarely is a sudden change evident across a broad range of tasks. In addition, developmental processes often show a great deal of continuity. Throughout childhood and adolescence, there are continuous increases in the abil- ity to regulate emotions, make friends, take other people’s perspectives, remember events, solve problems, and engage in many other activities. This does not mean that there are no sudden jumps. When we consider spe- cific tasks and processes, rather than broad domains, we see many discontinuities. Three-month-olds move from having almost no binocular depth perception to having adultlike levels within a week or two. Before age 7 months, infants rarely fear strangers, but thereafter, wariness of them develops quickly. Many toddlers move in a single day from being unable to walk without support to walking unsup- ported for a number of steps. After acquiring about one word per week between ages 12 and 18 months, toddlers undergo a vocabulary explosion, in which the number of words they know and use expands rapidly for years thereafter. Thus, although broad domains, such as intelligence and personality, rarely show discon- tinuous changes, specific aspects of development fairly often do. Whether development appears to be continuous or discontinuous often varies with whether the focus is on behavior or on underlying processes. Behaviors that emerge or disappear quite suddenly may reflect continuous underlying processes. Recall the case of infants’ stepping reflex. For the first two months after birth, if infants are supported in an upright position with their feet touching the ground, they will first lift one leg and then the other in a pattern similar to walking. At around age 2 months, this reflex suddenly disappears. Underlying the abrupt change in behavior, however, are gradual changes in two dimensions that under- lie the behavioral change—weight and leg strength. As babies grow, their gain in T H E M E 3 : D E V E L O P M E N T I s B O T H C O N T I N u O u s A N D D I s C O N T I N u O u s n 647 weight temporarily outstrips their gain in leg strength, and they become unable to lift their legs without help. Thus, when babies who have stopped exhibiting the stepping reflex are supported in a tank of water, making it easier for them to lift their legs, the stepping reflex reappears. Whether development appears continuous or discontinuous also depends on the time scale being considered. Recall that when a child’s height was measured every 6 months from birth to 18 years, the growth looked continuous (see Figure 1.3, page 16). When height was measured daily, however, development looked discontinu- ous, with occasional “growth days” sprinkled among numerous days without growth. One useful framework for thinking about developmental continuities and dis- continuities is to envision development as a road trip through the United States, from New York City to San Francisco. In one sense, the drive is a continuous pro- gression westward along Interstate 80. In another sense, the drive starts in the East and then proceeds (in an invariant order, without the possibility of skipping a region) through the Midwest and the Rocky Mountains before reaching its end point in California. The East includes the Atlantic Coast and the Appalachians, and it tends to be hilly, cloudy, and green; the Midwest tends to be flatter, dryer, and sunnier; the Mountain States are dryer and sunnier still, with extensive moun- tainous areas; and most of California is dry and sunny, with both extensive flat and extensive mountainous areas. The differences between regions in climate, color, and topography are large and real, but the boundaries between them are arbitrary. Is Ohio the westernmost eastern state or the easternmost midwestern state? Is eastern Colorado part of the Midwest or part of the Rocky Mountain region? The continuities and discontinuities in development are a lot like those on the road trip. Consider children’s conceptions of the self. At one level of analysis, the development of the self is continuous. Over the course of development, children (and adults) understand more and more about themselves. At another level of analy sis, milestones characterize each period of development. During infancy, chil- dren come to distinguish between themselves and other people, but they rarely if ever see themselves from another person’s perspective. During the toddler period, a trip along I-80 from New York to San Francisco takes a driver through four time zones in which the main features of the land change dramatically. the changes in topog- raphy, like those in development, however, are not discontinuous. adjacent areas tend to be highly similar, and classification of a border area as being in one zone or another is often quite arbitrary. In all of these ways, the journey resembles psychological development. San FranciscoSan Francisco 80 80 WEST COAST ROCKY MOUNTAINS MIDWEST EAST IA MO AR LA WI NE KS OK TX ND MN SD WY CO UT NMAZ NV OR WA ID MT CA IL KY TN MS AL GA SC NC VA WV NY ME FL IN MI OH PA NJ CT RI MA DE MD NH VT San Francisco Salt Lake City New York CityChicago Cleveland 648 n chapter 16 CONCLusIONs children increasingly view themselves as others might, which allows them to feel such emotions as shame and embarrassment. During the preschool period, chil- dren realize that certain of their personal characteristics, such as their gender, are fundamental and permanent, and they use this knowledge to guide their behavior. During the elementary school years, children increasingly think of themselves in terms of their competencies relative to other children’s (intelligence, athletic skill, popularity, and so forth). During adolescence, they come to recognize how differ- ently they themselves act in different situations. Thus, any statement about when a given competency emerges is somewhat arbi- trary, much like a statement about where a geographic region begins. Nonetheless, identifying the milestones helps us understand roughly where we are on the map. Theme 4: Mechanisms of Developmental Change As with so many issues, contemporary thinking about developmental change owes a large debt to the ideas of Jean Piaget. Within Piaget’s theory, change occurs through the interaction of assimilation and accommodation. Through assimilation, children interpret new experiences in terms of their existing mental structures; through accommodation, they revise their existing mental structures in accord with the new experiences. Thus, when we hear a truly unfamiliar type of music (for most of us, Javanese 12-tone music would fit this description), we as- similate the sounds to more familiar musical patterns, to the extent we can. At the same time, our understanding accommodates to the experience, so that when we next encounter the unfamiliar music, it will be a little easier to grasp and will feel a little less strange. A great deal has been learned about developmental mechanisms since Piaget formulated his theory. Some of the advances have come in understanding change at the biological level, others in understanding it at the behavioral level, and still others in understanding it at the level of cognitive processes. Biological Change Mechanisms Biological change mechanisms come into play from the moment a sperm unites with an egg. The sperm and the egg each contain half of the DNA that will consti- tute the child’s genotype throughout life. The genotype contains instructions that specify the rough outline of development, but all particulars are filled in by subse- quent interactions between the genotype and the environment. The way in which the brain forms after conception illustrates the complexity of change at the biological level. The first key process in brain development is neuro- genesis, which by the 3rd or 4th week after conception is producing roughly 10,000 brain cells per minute. About 100 days later, the brain contains just about all of the neurons it ever will have. As neurons form, a process of cell migration causes many of them to travel from where they were produced to their long-term location. Once neurons reach their destination, they undergo a process of differentiation, in which dendrites and axons grow out from the original cell body. Later in the pre- natal period, the process of myelination adds an insulating sheath over certain axons, which speeds up the rate of transmission of electrical signals along them. Myelina- tion continues through childhood and into adolescence. Yet another process, synaptogenesis, involves formation of synapses between the end of axons and the beginning of dendrites that allow neurotransmitters to transmit T H E M E 4 : M E C H A N I s M s O F D E V E L O P M E N T A L C H A N G E n 649 signals from neuron to neuron. The number of synapses increases rapidly from the prenatal period to early or middle childhood (depending on the particular brain area). By the end of this period of explosive growth, the number of synapses in the area far exceeds the number in the brains of adults. A process of pruning then re- duces the number of synapses. The greatest pruning occurs at different times in dif- ferent brain areas. Those synapses that are frequently used are maintained; those that are not are eliminated (“use it or lose it” at the biological level). The pruning of unused synapses makes information processing more efficient. The brain includes a number of areas that are specialized for specific functions. This specialization makes possible rapid and universal development of these func- tions and thus enhances learning of the relevant type of information. Some of the functions are closely linked to sensory and motor systems. The visual cortex is partic- ularly active in processing sights; the auditory cortex is particularly active in process- ing sounds; the motor cortex is particularly active in making movements; and so on. Other brain areas are specialized for functions that are not specific to any one sensory or motor system. The lim- bic system, located in the lower part of the brain, is particu- larly prominent in producing emotions. The prefrontal cortex is particularly involved in executive functioning. Some areas toward the back of the right hemisphere are particularly active in processing space, time, and number. All of these areas are involved in numerous other types of processing, and all types of processing involve numerous brain areas, but each of the areas is especially active in processing the type of information associated with it. Thus, biological mechanisms underlie both very specific and very general changes. Behavioral Change Mechanisms Behavioral change mechanisms describe responses to environmental contingencies that contribute to development. These learning mechanisms shape behavior from infants’ first days out of the womb onward. Habituation, Conditioning, Statistical Learning, and Rational Learning The capacity to habituate to familiar stimuli begins before fetuses leave the womb. By 30 weeks after conception (8 to 10 weeks before the typical time of birth), the central nervous system is sufficiently developed for habituation to occur, as re- flected in a fetus’s heart rate initially slowing down (a sign of interest) when a bell is rung next to the mother’s belly and then its returning toward the typical rate as the bell is rung repeatedly. Habituation continues after birth as well, and it is seen in changes in looking patterns as well as in heart-rate patterns. For example, when a picture of a face is shown repeatedly, infants reduce the time they spend looking at it, but they show renewed interest when a different face appears. Habituation motivates babies to seek new stimulation when they have learned from an experi- ence and thus helps them learn more. From their first days in the outside world, infants also can learn through classi- cal conditioning. If an initially neutral stimulus is repeatedly presented just before an unconditioned stimulus, it comes to elicit a similar response to that elicited by the unconditioned stimulus. Recall Little Albert, who, after repeatedly seeing a harmless Superior parietal cortex Dorsolateral prefrontal cortex the group average pattern of brain activa- tion for each of three increasingly difficult items (from left to right) on a problem- solving task that requires both execu- tive functioning and spatial processing as shown, the amount of activation in this slice of the brain increases with difficulty in the prefrontal cortex (toward the front of the brain, often involved in executive func- tioning) and in the superior parietal cortex (toward the back of the brain, often involved in spatial processing). (Data from Newman et al., 2003) © 2 0 0 3 E Ls E V IE R 650 n chapter 16 CONCLusIONs white rat and then hearing a frightening loud noise immediately after, came to fear the white rat (and also came to fear doctors and nurses wearing white lab coats). The fact that an infant would become afraid not only of the white rat but also of people with white coats illustrates the functioning of another key learning ability that is present from infancy: generalization. Although infants’ learning tends to be less general than that of older children, it is never completely literal. Infants gen- eralize the lessons of their past experience to new situations that differ at least in a few details from the original ones. Like older children, infants also learn through instrumental conditioning; behaviors that are rewarded become more frequent, and behaviors that do not lead to rewards become less frequent. Even young infants appear highly motivated to learn in this way: 2-month-olds express joy and interest while learning a contin- gency relation, and they often cry and express anger when a learned response no longer produces the expected results. Yet another mechanism that allows infants to acquire information rapidly is statistical learning. From birth onward, infants quickly learn the likelihood that one sight or sound will follow another. Because many events, including the sounds within words and certain daily activities, occur in predictable orders, sta- tistical learning helps infants anticipate other people’s actions and generate similar sequences of behavior themselves. Closely related to statistical learning is rational learning, which involves inte- grating the learner’s prior beliefs and biases with what actually occurs in the envi- ronment. When, for example, infants observe an adult pulling balls of two different colors out of a box, seemingly at random, and the ratio of the colors of those balls deviates greatly from that of all the balls in the box, the infants’ looking times sug- gest that they are surprised. Together with habituation and classical, instrumental, and statistical learning, such rational learning allows infants to acquire knowledge of the world from the first days following birth. Social Learning Children (and adults) learn a great deal from observing and interacting with other people. This social learning pervades our lives to such an extent that it is diffi- cult to think of it as a specific learning capability. However, when we compare humans with other animals, even close relatives such as chim- panzees and other apes, the omnipresence of social learning in people’s lives becomes apparent. Humans are far more skill- ful than any other animal in learning what others are trying to teach them; they also are far more inclined to teach oth- ers what they know. Among the crucial contributors to this social learning are imitation, social referencing, language, and guided participation. The first discernible form of social learning is imitation. At first, the imitation seems limited to behaviors that infants sometimes produce on their own, such as sticking out their tongue. However, by age 6 months, infants begin to imi- tate novel behaviors that they never make spontaneously. By 15 months, toddlers not only learn novel behaviors but can remember them and continue to produce them for at least a week. This imitation is not just “monkey see, monkey do.” When children of this age see a model try to do something Imitation starts in infancy. Ju D IT H K R A M E R / T H E I M A G E w O R K s T H E M E 4 : M E C H A N I s M s O F D E V E L O P M E N T A L C H A N G E n 651 but fail, they imitate what the model was trying to do rather than what the model actually did. Social learning influences socioemotional development as well as acquisition of knowledge. When an unfamiliar person enters the room, 12-month-olds look to their mother for guidance. If the mother’s face or voice shows fear, the baby tends to stay close to her; if the mother smiles, the baby is more likely to approach the stranger. Similarly, in the labora- tory, a baby of this age will cross the visual cliff if the mother smiles but not if she looks worried. Social learning also shapes children’s standards and values. From the second year of life, toddlers internalize their parents’ values and stan- dards and use them to guide and evaluate their own conduct. Later in development, peers, teachers, and other adults also influence children’s standards and values through the process of social learning. Peers, in particular, play a steadily increasing role over the course of childhood and adolescence. Imitation is not the only mechanism of social learning. Another is social scaffolding. In this change mechanism, an older and more knowl- edgeable person provides a learner with an overview of a given task, demonstrates how to do the most difficult parts, provides help with the difficult parts if necessary, and offers suggestions to the learner on how to proceed. Such scaffolding allows a beginner to do more than he or she could without help. Then, as the learner masters the basics of the task, the scaffolder transfers more and more responsibility to the learner until the learner is doing the entire task. Thus, adults and children collaborate to produce social learning. Cognitive Change Mechanisms Many of the most compelling analyses of developmental change are at the level of cognitive processes. Both general and specific information-processing mechanisms play important roles. General Information-Processing Mechanisms Four categories of information-processing mechanisms are especially general and pervasive: basic processes, strategies, metacognition, and content knowledge. Basic processes are the simplest, most broadly applicable, and earliest- developing general information-processing mechanisms. They overlap considerably with behavioral learning processes and include associating events with each other, rec- ognizing objects as familiar, recalling facts and procedures, encoding key features of events, and generalizing from one instance to another. Changes with age occur in the speed and efficiency of these basic processes, but all of the basic processes are present from infancy onward. These basic processes provide a foundation that allows infants to learn about the world from their very first days. Strategies also contribute to many types of development. Toddlers, for example, form strategies for achieving such goals as obtaining a toy that is out of reach or descending a steep surface; preschoolers form strategies for counting and solv- ing arithmetic problems; school-age children form strategies for playing games and getting along with others; and so on. Often, children acquire multiple strate- gies for solving a single kind of problem—for example, strategies for approaching Using tools to build and repair things is a common context for social scaffolding, in which the older and more experienced person helps the younger and less experi- enced person to operate at a higher level than would otherwise be possible, as well as to meet goals and acquire skills. IN s A D C O P H O T O G R A P H Y / A LA M Y 652 n chapter 16 CONCLusIONs unfamiliar children on a playground or for solving arithmetic problems. Knowing multiple strategies allows children to adapt to the demands of different problems and situations. Metacognition is a third type of cognitive process that contributes to devel- opment in large ways. For instance, increasing use of memory strategies stems in large part from children’s increasing realization that they are unlikely to remember large amounts of material verbatim without using such strategies. Among the most important applications of metacognition is adaptive choice among alternative strategies, for example in deciding whether rereading is necessary to understand text, whether to count or state a retrieved answer to solve an arithmetic problem, and whether to write an outline before beginning an essay. The cognitive control involved in executive functioning, such as inhibiting tempting but counterproduc- tive actions, being cognitively flexible, and considering other people’s perspectives, is another crucial type of metacognition. Content knowledge is a fourth pervasive contributor to cognitive change. The more children know about any topic—whether it be chess, soccer, dinosaurs, or language—the better able they are to learn and remember new information about it. Knowledge also facilitates learning of unfamiliar content by allowing children to draw analogies between the new content and content that is familiar to them. Domain-Specific Learning Mechanisms Infants acquire some complex competencies surprisingly rapidly, including basic perception and understanding of the physical world, language comprehension and production, interpretation of emotions, and attachment to caregivers. What seems to unite the varied capabilities that children acquire especially rapidly is their apparent evolutionary importance. Virtually everyone quickly and easily acquires abilities that are important to survival. A number of theorists have posited that the nearly universal, rapid learning in these domains is produced by domain-specific learning mechanisms that oper- ate on everyday experience to produce accurate conclusions about the world in domains of evolutionary importance. For example, even infants in their first year seem to expect bigger moving objects to produce stronger effects than smaller mov- ing objects. Similarly, toddlers’ word learning seems to be aided by the whole-object assumption (the idea that words used to label objects refer to the whole object rather than to a part of it) and the mutual exclusivity assumption (the idea that each object has a single name). These assumptions are usually correct for the words that young children hear, thus helping them learn what the words mean. Children’s informal theories about the main types of entities in the world— inanimate objects, people, and other living things—also facilitate their learning about them. The value of learning rapidly about the properties of people, other liv- ing things, and inanimate objects is clear; saying “More juice” to another person, for example, is considerably more likely to yield the desired outcome than is saying the same words to the family dog. Crucial in children’s informal theories, as in sci- entists’ formal ones, are causal relations that explain a large number of observations in terms of a few basic unobservable processes. Possessing basic understanding of key concepts—such as inertia and solidity for inanimate objects; goal-directed movement and growth for living things; and intentions, beliefs, and desires for people—helps children act appropriately in new situations. For example, when preschoolers meet an unfamiliar child, they assume that the child will have intentions, beliefs, and desires—an assumption that helps exceptional content knowledge can out- weigh all of adults’ usual intellectual advantages over children. On the day this photograph was taken, this 8-year-old boy became the youngest person ever to defeat a chess grandmaster (the ranking awarded to the greatest chess players in the world). T O P H A M / T H E I M A G E w O R K s T H E M E 5 : T H E s O C I O C u L T u R A L C O N T E x T s H A P E s D E V E L O P M E N T n 653 them understand the other child’s actions and react appropriately to them. These assumptions about other people’s minds aid the social understanding of children in all societies. Thus, both general and domain-specific cognitive learning mecha- nisms help children understand the world around them. Change Mechanisms Work Together Although it is often easiest to discuss different change mechanisms separately, it is crucial to remember that biological, cognitive, and behavioral mechanisms all reflect interactions between the person and the environment and that all types of mechanisms work together to produce change. For instance, consider effortful at- tention. The development of this capability reflects a combination of biological and environmental factors. On the biological side, genes influence the production of neurotransmitters that affect children’s ability to concentrate and ignore distrac- tions. Effortful attention also relies on the development of connections between two parts of the brain—the anterior cingulate, which is active in attention to goals, and the limbic area, which is active in emotional reactions. On the environmental side, the development of effortful attention can be influenced by the quality of par- enting a child receives—though this is true primarily for children with a particular genotype. For children with one form of a relevant gene, quality of parenting in- fluences the development of effortful attention, whereas for children with another form of the gene, quality of parenting has little effect on its development. Specific ex periences can also be influential; for example, playing specially designed com- puter games increases the activity of the anterior cingulate and thus the ability to sustain attention on both experimental tasks and intelligence tests. In short, var- ied types of mechanisms work together to produce development of even a single capability. Theme 5: The Sociocultural Context Shapes Development Children develop within a personal context of other people: families, friends, neigh- bors, teachers, and classmates. They also develop within an impersonal context of historical, economic, technological, and political forces, as well as societal beliefs, attitudes, and values. The impersonal context is as important as the personal one in shaping development. There is little reason to think that parents in developed societies in the twenty-first century love their children more than parents of the past did. Yet their children die less often, get sick less often, eat a more nutritious diet, and receive more formal schooling than did children from even the wealthi- est families of 100 or 200 years ago. Thus, when and where children grow up pro- foundly influences their lives. Growing Up in Societies with Different Practices and Values Values and practices that people within a society take for granted as “natural” often vary substantially among societies. These variations considerably influence the rate and form of development. Throughout the book, you encountered examples of this in every aspect of development, including in domains that are commonly thought of as governed entirely by maturation. For example, people often assume that the 654 n chapter 16 CONCLusIONs timing of walking and other motor skills in infancy is determined solely by biology, but babies who grow up in African tribes that strongly encourage infants’ motor development tend to walk and reach other motor milestones earlier than do infants in the United States. Similarly, infants in societies where babies sleep with their mothers for several years exhibit less fear at bedtime than do children in the United States, where babies rarely sleep with their mothers, or even in the same room with them, for more than 6 months. Emotional reactions provide another example of how cultural practices and values influence behavior, even when we might not expect them to do so. Infants in all societies that have been studied show the same attachment patterns, but the frequency of occurrence of each pattern varies with the values of the society. Rela- tive to babies in the United States, for instance, Japanese babies who are placed in the Strange Situation more often become very upset, showing the insecure- resistant attachment pattern. These differences in attachment patterns appear to be due to differing cultural values and practices. Japanese mothers traditionally encourage dependence in children and rarely leave their babies alone, which may lead the babies to become espe- cially upset when they are left alone in the Strange Situ- ation. In contrast, U.S. parents emphasize independence to a greater degree and more often leave babies alone in a room or with other people. Cultural influences such as these continue well beyond infancy. Japanese culture, for example, places a higher value on hiding negative emotions, especially anger, than does American culture, and Japanese mothers discourage their children from expressing negative emotions. Quite likely because of these cultural influences, Japanese pre- schoolers and school-age children less often express anger and other negative emotions than do U.S. peers. Simi- larly, child rearing in rural Mexican villages emphasizes cooperation and caring about others, and children raised in these villages are more likely to share their possessions than are children from Mexican cities or the United States. Culture influences not only parents’ actions but also children’s interpretations of those actions. For example, Chinese American mothers use a great deal of scold- ing and guilt to control their children. In the broader U.S. population, use of this disciplinary approach is associated with negative outcomes, but the association is not present among Chinese American children. The differing effectiveness of the disciplinary approaches may reflect children’s interpretations of their parents’ behavior. If children believe that scolding or authoritarian parenting is in their best interest, the behaviors can be effective. However, if children see such disciplin- ary approaches as reflecting negative parental feelings toward them, the discipline tends to be ineffective or harmful. Sociocultural differences exert a similar influence on cognitive development. They help determine which skills and knowledge children acquire—for instance, whether children learn to operate abacuses, iPads, or both. They also influence how well children learn skills that everyone acquires to some degree; for example, Australian Aboriginal children, whose lives will eventually depend on their abil- ity to trek through the desert to distant oases, develop spatial skills superior to those of urban Australian children. Finally, cultural values influence the educa- tional system, which in turn influences what and how deeply children learn. For the culture of Mexican villages successfully encourages cooperation and caring among children. w E s LE Y B O C x E / s C IE N C E s O u R C E T H E M E 5 : T H E s O C I O C u L T u R A L C O N T E x T s H A P E s D E V E L O P M E N T n 655 example, students in community-of-learners classrooms learn about fewer scien- tific topics than do children in traditional classrooms, but they learn about them in greater depth. Growing Up in Different Times and Places When and where children grow up profoundly influences their development. As noted earlier, in modern societies, children’s lives are greatly improved over what they were in the past, in terms of health, nutrition, shelter, and so on. Not all of the changes in modern societies have promoted children’s well-being, however. For example, in North America and Europe, far more children grow up with divorced parents than in the past, and these children are at risk for many prob- lems. On average, they are more prone to sadness and depression, have lower self-esteem, do less well in school, and are less socially competent than peers who live in intact families. Although most children from divorced families do not have serious problems, a minority do: engaging in delinquent activities, dropping out of school, and having children out of wedlock all are more com- mon among children whose parents are divorced. Other historical changes may result in children’s lives being different, but neither better nor worse. The great expansion of child care outside the home represents one such case. In the United States, about half of infants and three-fourths of 4-year- olds currently receive child care outside their homes—five times the rates in 1965. As this change was occurring, many people feared that such care would weaken attachment between babies and mothers. Others expressed hopes that such care would greatly stimulate cognitive development, especially of children from impov- erished backgrounds, because of the greater opportunities for interaction with other children and adults. In fact, the data indicate that neither the fears nor the hopes were justified. In almost all respects, children who receive care outside the home tend to develop similarly, both emotionally and cognitively, to those who do not. More generally, the same cultural or technological change can bring either posi- tive or negative effects, depending on who the child is and how the innovation is used. For instance, the Internet can be used to communicate with friends, which tends to strengthen friendships, but it can also be used for cyberbullying. Playing certain Internet games stimulates development of attention, but very high fre- quency of playing Internet games can harm the quality of friendships. Thus, in terms of health, comfort, and material well-being, children growing up today in modern societies are, on the whole, better off than those who grew up in the past— but in other ways, the picture is more mixed. Growing Up in Different Circumstances Within a Society Even among children growing up at the same time in the same society, differences in economic circumstances, family relationships, and peer groups lead to large dif- ferences in children’s lives. Economic Influences In every society, the economic circumstances of a child’s family considerably influence the child’s life. However, the degree of economic inequality within each society influences just how large a difference the economic circumstances make. In societies with large income inequalities, such as the United States, poor children’s 656 n chapter 16 CONCLusIONs academic achievement is far lower than that of children from wealthier families. In societies with smaller inequalities, such as Japan and Sweden, children from affluent families also do better academically than children from poorer families, but the differ- ences are smaller. It is not just academic achievement that is influenced by eco- nomic circumstances; all aspects of development are. Infants from impoverished families more often are insecurely attached to their mothers. Children and adolescents from impoverished families more often are rejected as friends and more often are lonely. Illegal substance use, crime, and depression also are more common among poor adolescents than among peers from wealthier backgrounds. These negative outcomes are unsurprising, given the many dis- advantages that poor children face. Relative to children who grow up in more affluent environments, poor children more often live in dangerous neighborhoods; grow up in homes with one or no biological parents; attend inferior day-care centers and schools; and have few books, magazines, and other intellectually stimulating material in their homes. The cumu- lative burden of these disadvantages, rather than any one of them, poses the greatest obstacle to successful development. Influences of Family and Peers Families and peer groups vary considerably in ways other than income, and many of these differences also have a substantial influence on development. In some families, regardless of income, parents are sensitive to babies’ needs and form close attachments with them; in others, this does not occur. In some families, again regardless of income, parents read to their children each night, thus helping the children to learn to read; in others, this practice does not occur. The influence of friends, other peers, teachers, and other adults varies in as many ways as that of families. Friends, for example, can provide companionship and feedback, contribute to self-esteem, and serve as a buffer against stress; during adolescence, they can be particularly important sources of sympathy and support. On the other hand, friends can also have a negative influence, drawing children and adolescents into reckless and aggressive behavior, including crime, drink- ing, and drug use. Thus, personal relationships, like economic circumstances, cul- ture, and technology, definitely influence development, but the effects of these influences vary with the particulars. Theme 6: Individual Differences Children differ on a huge number of dimensions—demographic characteristics (gender, race, ethnicity, SES), psychological characteristics (intellect, personal- ity, artistic ability), experiences (where they grow up; whether their parents are divorced; whether they participate in plays, bands, or organized sports), and so on. How can we tell which individual differences are the crucial ones for understanding children and predicting their futures? As illustrated in Figure 16.1, three characteristics—breadth of related char- acteristics, stability over time, and predictive value—are crucial in determin- ing the importance of any dimension of individual differences. First, as shown by the dotted vertical arrows, children’s status on the most important dimensions is this evocative photograph makes us wonder how the severe poverty faced by this Depression-era family affected the children’s subsequent lives. LI B R A R Y O F C O N G R E s s P R IN T s A N D P H O T O G R A P H s D IV Is IO N , w A s H IN G T O N D C T H E M E 6 : I N D I V I D u A L D I F F E R E N C E s n 657 associated with their status at that time on other important dimensions. Thus, one reason why intelligence is considered a central individual difference is that the higher a child’s IQ at a given age, the higher the child’s grades, achieve- ment test scores, and general knowledge tend to be at the same time (the dotted arrows in Figure 16.1). A second key characteristic is stability over time (the solid arrows in Figure 16.1). A dimension of individual differences is of greater inter- est if the higher or lower that children score on it early in development, the higher or lower they are likely to score on it later. Thus, another reason for interest in IQ is that children with high (or low) IQs usually grow into adults with high (or low) IQs. A third characteristic of major dimensions of individual differences is that a child’s status on the dimension predicts outcomes on other important character- istics in the future (the dashed arrows in Figure 16.1). Thus, a third reason for interest in IQ scores is that a person’s IQ during middle childhood and adolescence predicts that person’s later earnings, occupational status, and years of education. These three characteristics make clear why demographic variables such as gender, race, ethnicity, and SES are studied so often. Consider gender, for example. Gender differences are related to a wide variety of other differences. Boys tend to be larger, stronger, more physically active, and more aggressive; to play in larger groups; to be better at some forms of spatial thinking; and more often to have ADHD and math or reading disabilities. Girls tend to be more verbal, quicker to perceive emotions, better at writing, and more likely to express sympathy and empathy for people in dis- tress. Being male or female obviously is also stable over time. Finally, being male or female predicts future individual differences. If a newborn is female, it is likely that, compared with males, she will be more self-revealing with friends, more vulnerable to depression, more inclined to prosocial behavior, and more disposed to using rela- tional aggression. We next consider the extent to which several other variables show these three key characteristics of major individual differences. Breadth of Individual Differences at a Given Time Individual differences are not randomly distributed. Children who are high on one dimension also tend to be high on other, conceptually related dimensions. Thus, children who do well on one measure of intellect—language, memory, conceptual Achievement test scores General knowledge Achievement test scores Years of education GradesGrades Earnings Income 15-year-olds Age Adults7-year-olds IQ score IQ scoreIQ score FIGURE 16.1 Intelligence and indi- vidual differences Intelligence is con- sidered a crucial dimension of individual differences because IQ scores (1) correlate with other conceptually related dimensions such as general knowledge and grades at any one age (dotted arrows extending from IQ to other outcomes at age 7); (2) show considerable continuity over age (solid arrows); and (3) predict future outcomes, such as years of education and income in adulthood (dashed arrows connecting IQ score at age 7 to other later outcomes). 658 n chapter 16 CONCLusIONs understanding, problem solving, reading, or mathematics—tend to do well on others. Similarly, children who do well on one measure of social or emotional functioning—relations with parents, relations with peers, relations with teachers, self-esteem, prosocial behavior, and lack of aggression and lying—also tend to do well on others. Sometimes, as with the relation between intelligence and school achievement, the connections are very strong. More often, the relations are moder- ate. Thus, although children who get along well with their parents also tend to get along well with peers, there are many exceptions. Beyond intelligence and gender, two other crucial dimensions of individual differ- ences are attachment and self-esteem. Compared with their insecurely attached peers, toddlers who are securely attached to their mother tend to be more enthusiastic and positive about solving problems with her, to comply more often with her directives, and to obey her requests even when she isn’t present. Such children also tend to get along better with other toddlers and to be more sociable and more socially competent. Similarly, children and adolescents who are high in self-esteem also tend to be strong on many other dimensions of social and emotional functioning. They tend to be gen- erally hopeful and popular, to have many friends, and to have good academic and self- regulation skills. In contrast, those with low self-esteem tend to feel hopeless and to be prone to problems such as depression, aggression, and social withdrawal. Stability Over Time Many individual differences show moderate stability over time. For instance, people who have easy temperaments during infancy tend to continue to have easy tem- peraments in middle and later childhood. Similarly, elementary school children with ADHD, reading disabilities, or mathematics disabilities usually have lifelong difficulties in those areas. The reasons for such stability of psychological characteristics are to be found in the stability of both genes and environment. A child’s genotype remains identical over the course of development (though particular genes switch on and off at dif- ferent times). Most children’s environments remain fairly stable as well. Families that are middle-class when a child is born tend to remain middle-class; families that value education when the child is born usually continue to value education; families that are sensitive and supportive generally remain that way; and so on. Major changes, such as divorce and unemployment, do occur, and they affect chil- dren’s happiness, self-esteem, and other characteristics. Nonetheless, the stability of children’s environments, like the stability of their genes, contributes to the stability over time of their psychological functioning. Predicting Future Individual Differences on Other Dimensions Individual differences on some dimensions are related not only to future status on that dimension but also to future status on other dimensions. For example, children who are securely attached as infants tend as toddlers and preschoolers to have more social ties to their peers than do children who were insecurely attached as infants. When they reach school age, they tend to understand other children’s emotions rela- tively well and to be relatively skilled in resolving conflicts. When they reach adoles- cence and adulthood, they tend to form close attachments with romantic partners. All of these outcomes are consistent with the view that secure early attachment pro- vides a working model that influences subsequent relationships with other people. T H E M E 6 : I N D I V I D u A L D I F F E R E N C E s n 659 As with stability over time of a single dimension, the relative stability of most children’s environments contributes to these long-term continuities of psychologi- cal functioning. If children’s environments change in important ways, the typical continuities may be disrupted accordingly. Thus, stressful events such as divorce reduce the likelihood that children who were securely attached during infancy will continue to show the positive relations with peers usually associated with secure attachment. Determinants of Individual Differences Individual differences, like all aspects of development, are ultimately attributable to the interaction of children’s genes and the environments they encounter. Genetics For a number of important characteristics—including IQ, prosocial behavior, and empathy—about 50% of the differences among individuals in a given population are attributable to differences in genetic inheritance. The degree of genetic influence on individual differences tends to increase over the course of devel- opment. For example, correlations between the IQs of adopted children and their biological parents steadily increase over the course of childhood and adolescence, even if the children never meet or have any contact with their biological parents. One reason for this is that many genes related to intellectual func- tioning do not exercise their effects until late childhood or ado- lescence. Another reason is that over the course of development, children become increasingly free to choose environments that are in accord with their genetic predispositions. Experience Individual differences reflect children’s experiences as well as their genes. Consider just one major environmental influence: the par- ents who raise the children. The more speech that parents address to their toddlers, the more rapidly the toddlers recognize familiar words and learn new ones. The more that parents aim their scaf- folding at, but not beyond, the upper end of their children’s capabilities, the greater the improvement in their children’s problem solving. The more stimulating and responsive the home intellectual environment, the higher children’s IQ tends to be. Parents exert at least as large an influence on their children’s social and emo- tional development as on their intellectual development. For example, the like- lihood that children will adopt their parents’ standards and values appears to be influenced by the type of discipline their parents use with them. Similarly, parents influence their children’s willingness to share, especially if they discuss the reasons for sharing with their children and have good relationships with them. The effect of different types of parenting, like the effects of children’s other experiences, depends on the child. One example of this involves the development of conscience. For fearful children, the key factor determining whether the child inter- nalizes the parents’ moral values is gentle discipline. Fearful children may become so anxious in the face of rigorous discipline that they cannot focus on the moral values that the parents are trying to instill. For fearless children, on the other hand, the key factor is a positive relationship with one’s parents. Such fearless children Genetic similarities sometimes produce a striking physical resemblance between parent and child. We can only wonder whether this baby, as she develops, will come to resemble her father in other ways as well. C O u R T E s Y O F B E T H A N Y R IT T LE -J O H N s O N 660 n chapter 16 CONCLusIONs often do not respond to gentle discipline; they tend to internalize the parents’ val- ues only if they feel close to them. As an old adage states, “It’s a wise parent who knows his child.” Theme 7: Child-Development Research Can Improve Children’s Lives One of the few goals shared by virtually everyone is that children be as happy and healthy as possible. Understanding how children develop can contribute to this goal. Theories of development provide general principles for interpreting children’s behavior and for analyzing their problems. Empirical studies yield specific les- sons regarding how to promote children’s physical well-being, positive relationships with other people, and learning. In this section, we review practical implications of child-development research for raising children, educating them, and helping them overcome problems. Implications for Parenting Several principles of good parenting are so obvious that noting them might seem unnecessary. However, the number of children who are harmed each year by poor parenting makes it clear that these principles cannot be stated too often. Pick a Good Partner The first principle of good parenting comes into play before parenthood even begins: Pick a good partner. Given the importance of genetics, pick a partner whose physical, intellectual, and emotional characteristics suggest that he or she will pro- vide your child with good genes. Given the importance of the environment, pick a partner who will be a good mother or father. In terms of your child’s development, no decision is more important than picking a good partner. Ensure a Healthy Pregnancy An expectant mother should maintain a healthy diet, have regular checkups, and keep stress levels as low as possible to increase the likelihood of a successful preg- nancy. Equally important is avoiding teratogens such as tobacco, alcohol, and illegal drugs. Know Which Decisions Are Likely to Have a Long-Term Impact In addition to the joy they feel when their baby is born, new parents face a daunt- ing number of decisions. Fortunately, babies are quite resilient. In the context of a loving and supportive home, a wide range of choices work out about equally well. Some decisions that seem minor, however, can have important effects. One such decision involves the baby’s sleeping position: having a baby sleep on his or her back, rather than on his or her stomach, reduces the possibility of SIDS. In other cases, the lesson of child-development research is that early problems are often transitory, so there is no reason to worry about them. Colic, which affects about 10% of babies, is one such problem. A colicky baby’s frequent, high-pitched, grating, sick-sounding cries are difficult for parents to bear, but they have no long- term implications for the baby’s development. In the short run, the best approach is to soothe the baby to the extent possible and not feel at fault if the effort fails. In T H E M E 7 : C H I L D - D E V E L O P M E N T R E s E A R C H C A N I M P R O V E C H I L D R E N ’ s L I V E s n 661 the longer run, the best path for parents is to relax, seek social support, and obtain babysitting help to allow some time off from caregiving—and to remember that colic usually ends by the time babies are 3 months old. Form a Secure Attachment Most parents have no difficulty forming a secure attachment with their baby, but some parents and babies do not form such bonds. One reason is genetics: variant forms of certain genes can influence the likelihood of a child’s forming a secure parental attachment, in at least some circumstances. Of course, no one can control the genes that babies inherit, but parents and other caretakers can maximize the likelihood of a baby’s becoming securely attached by maintain- ing a positive approach in their caregiving and by being responsive to the baby’s needs. This is easier said than done, of course, and other dimensions of a baby’s temperament, as well as the parents’ attitude and responsiveness, influence the quality of attachment. However, even when babies are initially irritable and dif- ficult, programs that teach parents how to be responsive and positive with them can lead to more secure attachments. Provide a Stimulating Environment The home environment has a great deal to do with children’s learning. One good example involves reading acquisition. Telling stories to toddlers and preschoolers, being responsive when they tell stories, and reading to them are positively related to later reading achievement. One reason is that such activities promote phonologi- cal awareness (the ability to identify the component sounds within words). Nurs- ery rhymes seem to be particularly effective in this regard; children who repeatedly hear Green Eggs and Ham, for instance, generally learn to appreciate the similarities and differences in Sam, ham, am, and related words. Phonological awareness helps children learn to sound out words, which, in turn, helps them learn to retrieve the words’ identities quickly and effortlessly. Successful early reading leads children to read more, which helps them improve their reading further over the course of schooling. More generally, the more stimulating the intellectual environment, the more eager children will be to learn. Family activities, such as looking at photo albums and reminiscing about the people and settings they depict, provide both stim- ulation and warm, positive feelings for many children.As IA I M A G E s G R O u P P T E L T D / A LA M Y 662 n chapter 16 CONCLusIONs Implications for Education Theories and research on child development hold a number of further lessons for how to educate children most effectively. Consider the instructional implications of several major theories of cognitive development. Piaget’s theory emphasizes the importance of the child’s active involvement, both mental and physical, in the learning process. This active involvement is especially important in helping children master counterintuitive ideas. For example, the physical experience of walking around a pivot while holding a long metal rod at points close to and far from the pivot allowed children to overcome a widely held misconception that previous paper-and-pencil physics lessons had failed to correct—the misconception that all parts of an object must move at the same speed. Information-processing theories suggest that analyzing the types of information available to children in everyday activities can improve learning. One such analysis indicated that the simple board game Chutes and Ladders provided visual, audi- tory, kinesthetic, and temporal information that could help children learn the sizes of numbers. Consistent with this analysis, having children from low-income fami- lies play a game based on Chutes and Ladders improved the children’s understand- ing of the sizes of numbers, as well as their counting, recognition of numbers, and arithmetic learning. Sociocultural theories emphasize the need to turn classrooms into communi- ties of learners in which children cooperate with one another in their pursuit of knowledge. Rather than following the traditional model of instruction in which teachers lecture and children take notes, community-of-learners classrooms follow an approach in which teachers provide the minimum guidance needed for chil- dren to learn and gradually decrease their directive role as children’s competence increases. Such programs also encourage children to make use of the resources of the broader community—children and teachers at other schools, outside experts, reference books, websites, and so on. The approach can be effective not only in building intellectual skills but also in promoting desirable values, such as personal responsibility and mutual respect. Implications for Helping Children at Risk Several principles that have emerged from empirical research offer valuable guid- ance for helping children at risk for serious developmental problems. The Importance of Timing Providing interventions at the optimal time is crucial in a variety of developmental contexts. One important example involves efforts to help children at risk for learning difficulties. All theories of cognitive development indicate that such difficulties should be addressed early, before children lose confidence in their ability to learn or become resentful toward schools and teachers. This realization, together with research docu- menting that many children from impoverished backgrounds have difficulty in school, laid the groundwork for Project Head Start and a variety of experimental preschool programs. Evaluations of the programs’ effects indicate that both the small experi- mental programs and Project Head Start increase children’s IQs and achievement test scores by the end of the programs and for a few years thereafter. Subsequently, the pos- itive effects on IQ and academic achievement usually fade, but other positive effects continue. At-risk children who participate in such programs are less likely to ever be T H E M E 7 : C H I L D - D E V E L O P M E N T R E s E A R C H C A N I M P R O V E C H I L D R E N ’ s L I V E s n 663 held back in school or assigned to special-education classes than are those who do not participate, and they are more likely to graduate from high school and go to college. Even greater positive effects of early educational programs are possible, as illus- trated by the Abecedarian Project. Designed to show what could be achieved through an optimally staffed, highly funded, and carefully designed program that started dur- ing infancy and lasted through age 5, the Abecedarian Project produced gains in both academic achievement and social skills that continued throughout childhood and adolescence. Its results demonstrate that it is possible for intensive programs that start early to have substantial, lasting benefits on poor children’s academic achievement. Early detection of child maltreatment, and rapid intervention to end it, is also crucial. In the United States, roughly 1% of children age 17 and younger are abused or neglected in a given year. Inadequate care, physical abuse, and sexual abuse are the three most common problems. Parents who are stressed economically, have few friends, use alcohol and illegal drugs, or are being abused by their partner are the most likely to mistreat their children. Knowing the characteristics of abused and neglected children can help teach- ers and others who come into contact with children recognize potential problems early and alert social service agencies so that they can investigate and remedy the problems. Children who are maltreated tend to have difficult temperaments, to have few friends, to be in poor physical or mental health, to do poorly in school, and to show abnormal aggression or passivity. Adolescents who are maltreated may be depressed or hyperactive, use drugs or alcohol, and have sexual problems such as promiscuity or abnormal fearfulness. Early recognition of such signs of abuse can literally save a child’s life. Biology and Environment Work Together Another principle with important practical implications is that biology and envi- ronment work together to produce all behavior. This principle has proved impor- tant in designing treatments for ADHD. Although stimulant drugs such as Ritalin the intellectual stimulation children receive and the academic skills they acquire in project head Start classrooms such as this one boost their IQ and achievement test scores at program completion and some- times for several years thereafter. P A u L C O N K LI N / P H O T O E D IT 664 n chapter 16 CONCLusIONs are the best-known treatment for this problem, research has shown that when medications are used alone, their benefits usually end as soon as children stop tak- ing them. Longer-lasting benefits require behavioral therapy as well as medication. One effective behavioral treatment is to teach the children strategies for screening out distractions. The medications calm children with ADHD sufficiently that they can benefit from the therapy; the therapy helps them learn effective ways for deal- ing with their problems and for interacting with other people. Every Problem Has Many Causes An additional principle that has proved useful for helping children with develop- mental problems is that trying to identify the cause of any particular problem is futile; problems almost always have multiple causes. The greater the number of risks, the more likely children will have low IQs, poor socioemotional skills, and psychiatric disorders. Accordingly, providing effective treatment often requires addressing many particular difficulties. This principle has provided useful guid- ance for intervening with children who are rejected by other children. Helping these children gain better social skills requires increasing their understanding of other people. It also requires helping them learn new strategies, such as how to enter an ongoing group interaction unobtrusively and how to resolve conflicts without resorting to aggression. It also requires helping them learn from their own experience, for example, by monitoring the success of the different strategies they try. Together, these approaches can help rejected children make friends and become better accepted. Improving Social Policy Even if you do not have children of your own and rarely interact with other people’s children, your actions as a citizen can influence their lives. Votes in elections and referenda, opinions expressed in informal discussions, and participation in advocacy organizations all can make a difference. Knowledge of child-development research can inform your stances on many issues relevant to children. The conclusions that you reach will, and should, reflect your values as well as the evidence. For example, reductions in class size in kindergarten through 3rd grade classrooms have had variable effects on student achievement. A large-scale, well-implemented study in Tennessee, for instance, indicated positive effects on student achievement (Krueger, 1999), whereas a large-scale, well-implemented study in California did not show any effect on achievement (Stecher, McCaffrey, & Bugliari, 2003). Teachers and parents appeared to be pleased with the class-size reductions in both cases and believed that the smaller classes helped their children. Are these outcomes worth the substantial cost of hiring the number of teachers needed to implement such reform (roughly $1.7 billion per year in California)? Re- search cannot answer this question, because the answer depends on values as well as data. How expensive is too expensive? Nonetheless, as the example illustrates, knowing the scientific evidence can help us, as citizens, make better-informed decisions. Maternity Leave Should society require employers to grant paid maternity leave in the months after a baby is born, and if so, for how long? Knowing that long hours of day care before an infant is 9 months old may sometimes have negative effects on early cognitive T H E M E 7 : C H I L D - D E V E L O P M E N T R E s E A R C H C A N I M P R O V E C H I L D R E N ’ s L I V E s n 665 development argues in favor of society’s making it easier for parents to take mater- nity leave. However, other considerations such as economic costs are also impor- tant; as noted above, the scientific evidence alone can never be decisive. Day Care Similar debates have arisen about whether the general society should subsidize day- care payments for parents of young children. One argument against such a policy has been the claim that children develop more successfully if they stay at home with one of their parents or other relatives than if they attend day care. This argument has turned out to be flawed, however. Children who attend good-quality day care develop similarly to children who receive care at home from their parents. Eyewitness Testimony Understanding child development is also vital for deciding whether children should be allowed to testify in court cases and for obtaining the most accurate testimony possible from them. Each year, more than 100,000 children in the United States tes- tify in court, many of them in trials involving allegations of abuse. Often, the child and the accused are the only ones who witnessed the events. Research indicates that, in general, the accuracy of testimony increases with age; 8-year-olds recall more than do 6-year-olds, and 6-year-olds recall more than do 4-year-olds. However, when children are shielded from misleading and repeated questioning, even 4- and 5-year- olds usually provide accurate testimony about the types of issues that are central in court cases. Given the high stakes in such cases, using the lessons of research to elicit the most accurate possible testimony from children is essential for a just verdict. Child-development research holds lessons for numerous other social problems as well. Research on the causes of aggression has led to programs such as Fast Track, which are designed to teach aggressive children to manage their anger and avoid violence. Research on the roots of morality has led to programs such as the Child Development Project, designed to encourage students to help others children are naturally curious about the world; encouraging this curiosity, and chan- neling it in fruitful directions, is among the most vital goals facing parents and society alike.JE F F G R E E N B E R G / A LA M Y 666 n chapter 16 CONCLusIONs Critical Thinking Questions 1. What qualities of children influence the way that other people act toward them, and how do these actions influence their development? 2. Individual differences show some stability over time. How do genes and environment contribute to this stability? 3. How would growing up in one developed society rather than another—for example, the United States rather than Japan— be expected to influence a child’s development? 4. How have the changes that have taken place in the United States over the past century influenced children’s development? Has the overall effect of the changes on children been predominantly beneficial or predominantly harmful? 5. What findings that you read about in this book surprised you the most? Were there any findings or conclusions that you just don’t believe? 6. What practical lessons have you learned from this course that will influence the way that you raise your children if you have them? who are in need. Research on the effects of poverty has provided the basis for the Abecedarian Project and other early education efforts. There is no end of social problems; understanding child development can help address the ones that affect children’s futures. G-1 Glossary accommodation the process by which people adapt current knowledge structures in response to new experiences (p. 133) achievement motivation refers to whether children are motivated by learning goals, seeking to improve their competence and master new material, or by performance goals, seeking to re- ceive positive assessments of their competence or to avoid negative assessments (p. 359) activating influences potential result of cer- tain fluctuations in sex-linked hormone levels affecting the contemporaneous activation of the nervous system and corresponding behavioral responses (p. 598) adrenarche period prior to the emergence of visible signs of puberty during which the ad- renal glands mature, providing a major source of sex steroid hormones; correlates with the onset of sexual attraction (p. 619) adult attachment models working models of attachment in adulthood that are believed to be based on adults’ perceptions of their own child- hood experiences—especially their relation- ships with their parents—and of the influence of these experiences on them as adults (p. 432) affiliation tendency to affirm connection with others through being emotionally open, empa- thetic, or cooperative (p. 594) affordances the possibilities for action offered by objects and situations (p. 199) aggression behavior aimed at harming or in- juring others (p. 577) aggressive-rejected children a category of so- ciometric status that refers to children who are especially prone to physical aggression, disrup- tive behavior, delinquency, and negative be- havior such as hostility and threatening others (p. 535) alleles two or more different forms of a gene (p. 92) altruistic motives helping others for reasons that initially include empathy or sympathy for others and, at later ages, the desire to act in ways consistent with one’s own conscience and moral principles (p. 569) amniotic sac a transparent, fluid-filled mem- brane that surrounds and protects the fetus (p. 48) anal stage the second stage in Freud’s theory, lasting roughly from 1 to 3 years of age, in which the primary source of pleasure comes from def- ecation (p. 344) androgen insensitivity syndrome (AIS) condi- tion during prenatal development in which an- drogen receptors malfunction in genetic males, impeding the formation of male external geni- talia; in these cases, the child may be born with female external genitalia (p. 599) androgens class of steroid hormones that nor- mally occur at higher levels in males than in fe- males and that affect physical development and functioning from the prenatal period onward (p. 598) A-not-B error the tendency to reach for a hidden object where it was last found rather than in the new location where it was last hidden (p. 136) apoptosis genetically programmed cell death (p. 47) assertion tendency to take action on behalf of the self through competitive, independent, or aggressive behaviors (p. 594) assimilation the process by which people translate incoming information into a form that fits concepts they already understand (p. 133) association areas parts of the brain that lie be- tween the major sensory and motor areas and that process and integrate input from those areas (p. 109) attachment an emotional bond with a specific person that is enduring across space and time. Usually, attachments are discussed in regard to the relation between infants and specific care- givers, although they can also occur in adult- hood. (p. 427) attachment theory theory based on John Bowl- by’s work that posits that children are biologi- cally predisposed to develop attachments with caregivers as a means of increasing the chances of their own survival (p. 428) attention-deficit hyperactivity disorder (ADHD) a syndrome that involves difficulty in sustaining attention (p. 370) auditory localization perception of the loca- tion in space of a sound source (p. 182) authoritarian parenting a parenting style that is high in demandingness and low in responsive- ness. Authoritarian parents are nonresponsive to their children’s needs and tend to enforce their demands through the exercise of parental power and the use of threats and punishment. They are oriented toward obedience and authority and ex- pect their children to comply with their demands without question or explanation. (p. 474) authoritative parenting a parenting style that is high in demandingness and support- iveness. Authoritative parents set clear stan- dards and limits for their children and are firm about enforcing them; at the same time, they allow their children considerable au- tonomy within those limits, are attentive and responsive to their children’s concerns and needs, and respect and consider their chil- dren’s perspective. (p. 473) autobiographical memories memories of one’s own experiences, including one’s thoughts and emotions (p. 160) axons neural fibers that conduct electrical sig- nals away from the cell body to connections with other neurons (p. 106) babbling repetitive consonant–vowel sequences (“bababa . . .”) or hand-shapes (for learners of signed languages) produced during the early phases of language development (p. 230) basic level the middle level, and often the first level learned, within a category hierarchy, such as “dog” in the animal/dog/poodle example (p. 264) basic processes the simplest and most fre- quently used mental activities (p. 150) behavioral inhibition a temperamentally based style of responding characterized by the tendency to be particularly fearful and restrained when dealing with novel or stressful situations (p. 409) behavior genetics the science concerned with how variation in behavior and development re- sults from the combination of genetic and envi- ronmental factors (p. 99) behavior modification a form of therapy based on principles of operant conditioning in which reinforcement contingencies are changed to en- courage more adaptive behavior (p. 351) G-2 n G L O S S A R Y bidirectionality of parent–child interactions the idea that parents and their children are mu- tually affected by one another’s characteristics and behaviors (p. 478) bilingualism the ability to use two languages (p. 223) binocular disparity the difference between the retinal image of an object in each eye that results in two slightly different signals being sent to the brain (p. 181) body image an individual’s perception of, and feelings about, his or her own body (p. 618) Carolina Abecedarian Project comprehensive and successful enrichment program for children from low-income families (p. 318) categorical perception the perception of speech sounds as belonging to discrete categories (p. 224) category hierarchy categories that are related by set–subset relations, such as animal/dog/ poodle (p. 263) cell body a component of the neuron that con- tains the basic biological material that keeps the neuron functioning (p. 106) centration the tendency to focus on a single, perceptually striking feature of an object or event (p. 139) cephalocaudal development the pattern of growth in which areas near the head develop earlier than areas farther from the head (p. 48) cerebral cortex the “gray matter” of the brain that plays a primary role in what is thought to be par- ticularly humanlike functioning, from seeing and hearing to writing to feeling emotion (p. 108) cerebral hemispheres the two halves of the cortex; for the most part, sensory input from one side of the body goes to the opposite hemi- sphere of the brain (p. 109) cerebral lateralization the specialization of the hemispheres of the brain for different modes of processing (p. 109) child maltreatment intentional abuse or ne- glect that endangers the well-being of anyone under the age of 18 (p. 369) chromosomes molecules of DNA that transmit genetic information; chromosomes are made up of DNA (p. 89) chronosystem in the bioecological model, his- torical changes that influence the other systems (p. 368) classical conditioning a form of learning that consists of associating an initially neutral stim- ulus with a stimulus that always evokes a par- ticular reflexive response (p. 201) clinical interview a procedure in which ques- tions are adjusted in accord with the answers the interviewee provides (p. 25) cliques friendship groups that children volun- tarily form or join themselves (p. 526) cognitive development the development of thinking and reasoning (p. 15) colic excessive, inconsolable crying by a young infant for no apparent reason (p. 74) collaboration coordination of assertion and af- filiation in behavior, which is associated with gender-role flexibility and more common among girls than boys (p. 594) collective monologue conversation between children that involves a series of non sequiturs, the content of each child’s turn having little or nothing to do with what the other child has just said (p. 244) comprehension with regard to language, un- derstanding what others say (or sign or write) (p. 217) comprehension monitoring process of keeping track of one’s understanding of a verbal descrip- tion or text (p. 327) conception the union of an egg from the mother and a sperm from the father (p. 42) concepts general ideas or understandings that can be used to group together objects, events, qualities, or abstractions that are similar in some way (p. 260) concrete operational stage the period (7 to 12 years) within Piaget’s theory in which children become able to reason logically about concrete objects and events (p. 135) conditioned response (CR) in classical con- ditioning, the originally reflexive response that comes to be elicited by the conditioned stimulus (p. 201) conditioned stimulus (CS) in classical condi- tioning, the neutral stimulus that is repeatedly paired with the unconditioned stimulus (p. 201) conduct disorder (CD) a disorder that in- volves severe antisocial and aggression be- haviors that inflict pain on others or involve destruction of property or denial of the rights of others (p. 580) cones the light-sensitive neurons that are highly concentrated in the fovea (the central re- gion of the retina) (p. 174) congenital adrenal hyperplasia (CAH) condi- tion during prenatal development in which the adrenal glands produce high levels of androgens; sometimes associated with masculinization of external genitalia in genetic females; and some- times associated with higher rates of masculine- stereotyped play in genetic females (p. 599) connectionism a type of information- processing approach that emphasizes the simul- taneous activity of numerous interconnected processing units (p. 252) conscience an internal regulatory mechanism that increases the individual’s ability to conform to standards of conduct accepted in his or her culture (p. 566) conservation concept the idea that merely changing the appearance of objects does not nec- essarily change other key properties (p. 139) continuous development the idea that changes with age occur gradually, in small increments, like that of a pine tree growing taller and taller (p. 13) contrast sensitivity the ability to detect differ- ences in light and dark areas in a visual pattern (p. 174) control group the group of children in an ex- perimental design who are not presented the ex- perience of interest but in other ways are treated similarly (p. 31) controversial (peer status) a category of socio- metric status that refers to children or adoles- cents who are liked by quite a few peers and are disliked by quite a few others (p. 537) corpus callosum a dense tract of nerve fibers that enable the two hemispheres of the brain to communicate (p. 109) correlation the association between two vari- ables (p. 29) correlational designs studies intended to indi- cate how two variables are related to each other (p. 28) co-rumination extensively discussing and self- disclosing emotional problems with another person (p. 396) counting-on strategy counting up from the larger addend the number of times indicated by the smaller addend (p. 34) critical period the time during which language develops readily and after which (sometime be- tween age 5 and puberty) language acquisition is much more difficult and ultimately less suc- cessful (p. 220) cross-gender-typed behaviors associated with the gender other than that of a given person (p. 595) crossing over the process by which sections of DNA switch from one chromosome to the other; crossing over promotes variability among individuals (p. 91) cross-sectional design a research method in which children of different ages are compared on a given behavior or characteristic over a short period (p. 32) G L O S S A R Y n G-3 crowds groups of adolescents who have similar stereotyped reputations; among U.S. high school students, typical crowds may include the “brains,” “jocks,” “loners,” “burnouts,” “punks,” “populars,” “elites,” “freaks,” or “nonconformists” (p. 527) crystallized intelligence factual knowledge about the world (p. 300) cultural tools the innumerable products of human ingenuity that enhance thinking (p. 157) deferred imitation the repetition of other peo- ple’s behavior a substantial time after it origi- nally occurred (p. 136) dendrites neural fibers that receive input from other cells and conduct it toward the cell body in the form of electrical impulses (p. 106) dependent variable a behavior that is measured to determine whether it is affected by exposure to the independent variable (p. 31) developmental resilience successful develop- ment in spite of multiple and seemingly over- whelming developmental hazards (p. 80) differential (or discrete) emotions theory a theory about emotions, held by Tomkins, Izard, and others, in which emotions are viewed as in- nate and discrete from one another from very early in life, and each emotion is believed to be packaged with a specific and distinctive set of bodily and facial reactions (p. 386) differentiation the extraction from the con- stantly changing stimulation in the environment of those elements that are invariant, or stable (p. 199) direction-of-causation problem the concept that a correlation between two variables does not indicate which, if either, variable is the cause of the other (p. 29) discontinuous development the idea that changes with age include occasional large shifts, like the transition from caterpillar to cocoon to butterfly (p. 13) display rules a social group’s informal norms about when, where, and how much one should show emotions and when and where displays of emotion should be suppressed or masked by dis- plays of other emotions (p. 420) distributional properties the phenomenon that in any language, certain sounds are more likely to appear together than are others (p. 228) DNA (deoxyribonucleic acid) molecules that carry all the biochemical instructions involved in the formation and functioning of an or- ganism (p. 89) dominant allele the allele that, if present, gets expressed (p. 92) dose–response relation a relation in which the effect of exposure to an element increases with the extent of exposure (prenatally, the more exposure a fetus has to a potential teratogen, the more se- vere its effect is likely to be) (p. 59) dual representation the idea that a symbolic ar- tifact must be represented mentally in two ways at the same time—both as a real object and as a symbol for something other than itself (p. 252) dynamic-systems theories a class of theories that focus on how change occurs over time in complex systems (p. 161) dyslexia inability to read and spell well despite normal intelligence (p. 326) effect size magnitude of difference between two group’s averages and the amount of overlap in their distributions (p. 615) ego in psychoanalytic theory, the second per- sonality structure to develop. It is the rational, logical, problem-solving component of person- ality. (p. 343) egocentrism the tendency to perceive the world solely from one’s own point of view (p. 138) Electra complex Freud’s term for the conflict experienced by girls in the phallic stage when they develop unacceptable romantic feelings for their father and see their mother as a rival. (The complex is named after a figure in Greek mythology who arranged for the murder of her mother.) (p. 345) embryo the name given to the developing or- ganism from the 3rd to 8th week of prenatal de- velopment (p. 45) embryonic stem cells embryonic cells, which can develop into any type of body cell (p. 45) emotion emotion is characterized by neural and physiological responses, subjective feelings, cognitions related to those feelings, and the de- sire to take action (p. 385) emotional intelligence a set of abilities that contribute to competence in the social and emo- tional domains (p. 384) emotional self-regulation the process of initi- ating, inhibiting, or modulating internal feeling states and related physiological processes, cogni- tions, and behaviors (p. 398) enactive experience learning through expe- riencing the reactions one’s behavior evokes in others (p. 604) encoding the process of representing in memory information that draws attention or is considered important (p. 150) entity/helpless orientation a general tendency to attribute success and failure to enduring as- pects of the self and to give up in the face of failure (p. 359) entity theory a theory that a person’s level of intelligence is fixed and unchangeable (p. 359) environment every aspect of an individual and his or her surroundings other than genes (p. 88) epigenesis the emergence of new structures and functions in the course of development (p. 42) epigenetics the study of stable changes in gene expression that are mediated by the environ- ment (p. 11) equilibration the process by which children (or other people) balance assimilation and ac- commodation to create stable understanding (p. 133) erogenous zones in Freud’s theory, areas of the body that become erotically sensitive in succes- sive stages of development (p. 342) essentialism the view that living things have an essence inside them that makes them what they are (p. 276) ethnic identity individuals’ sense of belonging to an ethnic or racial group, including the de- gree to which they associate their thinking, perceptions, feelings, and behavior with mem- bership in that group (p. 450) ethology the study of the evolutionary bases of behavior (p. 362) event-related potentials (ERPs) changes in the brain’s electrical activity that occur in re- sponse to the presentation of a particular stim- ulus (p. 110) exosystem in the bioecological model, environ- mental settings that a person does not directly experience but that can affect the person indi- rectly (p. 368) experience-dependent plasticity the process through which neural connections are created and reorganized throughout life as a function of an individual’s experiences (p. 116) experience-expectant plasticity the pro- cess through which the normal wiring of the brain occurs in part as a result of experiences that every human who inhabits any reasonably normal environment will have (p. 115) experimental control the ability of researchers to determine the specific experiences that children have during the course of an experiment (p. 31) experimental designs a group of approaches that allow inferences about causes and effects to be drawn (p. 30) experimental group a group of children in an experimental design who are presented the ex- perience of interest (p. 31) G-4 n G L O S S A R Y external validity the degree to which results can be generalized beyond the particulars of the research (p. 24) failure to thrive a condition in which infants become malnourished and fail to grow or gain weight for no obvious medical reason (p. 120) false-belief problems tasks that test a child’s un- derstanding that other people will act in accord with their own beliefs even when the child knows that those beliefs are incorrect (p. 268) family dynamics the way in which the family operates as a whole (p. 470) fast mapping the process of rapidly learning a new word simply from hearing the contrastive use of a familiar and the unfamiliar word (p. 237) fetal alcohol spectrum disorder (FASD) the harmful effects of maternal alcohol con- sumption on a developing fetus. Fetal alcohol syndrome (FAS) involves a range of effects, in- cluding facial deformities, mental retardation, attention problems, hyperactivity, and other de- fects. Fetal alcohol effects (FAE) is a term used for individuals who show some, but not all, of the standard effects of FAS. (p. 62) fetus the name given to the developing or- ganism from the 9th week to birth (p. 45) fluid intelligence ability to think on the spot to solve novel problems (p. 299) Flynn effect consistent rise in average IQ scores that has occurred over the past 80 years in many countries (p. 313) foreclosure status a category of identity status in which the individual is not engaged in any identity experimentation and has established a vocational or ideological identity based on the choices or values of others (p. 447) formal operational stage the period (12 years and beyond) within Piaget’s theory in which people become able to think about abstractions and hypothetical situations (p. 135) fraternal twins twins that result when two eggs happen to be released into the fallopian tube at the same time and are fertilized by two different sperm; fraternal twins have only half their genes in common (p. 47) friendship an intimate, reciprocated positive relationship between two people (p. 513) frontal lobe associated with organizing be- havior; the one that is thought responsible for the human ability to plan ahead (p. 109) functionalist approach a theory of emotion, proposed by Campos and others, that argues that the basic function of emotions is to pro- mote action toward achieving a goal. In this view, emotions are not discrete from one an- other and vary somewhat based on the social en- vironment. (p. 386) gametes (germ cells) reproductive cells—egg and sperm—that contain only half the genetic material of all the other cells in the body (p. 42) gang a loosely organized group of adolescents or young adults who identify as a group and often engage in illegal activities (p. 528) gender constancy realization that gender is in- variant despite superficial changes in a person’s appearance or behavior (p. 600) gender dysphoria disorder psychiatric diag- nosis included in the DSM-5 to refer to chil- dren who identify with the other gender and indicate cross-gender-typed interests (p. 598) gender-essentialist statements remarks about males’ and females’ activities and characteristics phrased in language that implies they are in- herent to the group as a whole (p. 604) gender identity awareness of oneself as a boy or a girl (p. 600) gender-role flexibility recognition of gender roles as social conventions and adoption of more flexible attitudes and interests (p. 612) gender-role intensification heightened con- cerns with adhering to traditional gender roles that may occur during adolescence (p. 612) gender schema filter initial evaluation of infor- mation as relevant for one’s own gender (p. 602) gender schemas organized mental representa- tions (concepts, beliefs, memories) about gender, including gender stereotypes (p. 601) gender segregation children’s tendency to as- sociate with same-gender peers and to avoid other-gender peers (p. 609) gender stability awareness that gender remains the same over time (p. 600) gender-typed behaviors associated with a given person’s gender (p. 595) gender typing the process of gender socializa- tion and development (p. 595) generativity refers to the idea that through the use of the finite set of words and morphemes in humans’ vocabulary, we can put together an infi- nite number of sentences and express an infinite number of ideas (p. 217) genes sections of chromosomes that are the basic unit of heredity in all living things (p. 89) genital stage the fifth and final stage in Freud’s theory, beginning in adolescence, in which sexual maturation is complete and sexual intercourse be- comes a major goal (p. 345) genome each person’s complete set of heredi- tary information (p. 11)) genome the complete set of genes of any or- ganism (p. 88) genotype the genetic material an individual in- herits (p. 88) gesture–speech mismatches phenomenon in which hand movements and verbal statements convey different ideas (p. 333) g (general intelligence) cognitive processes that influence the ability to think and learn on all intellectual tasks (p. 299) glial cells cells in the brain that provide a va- riety of critical supportive functions (p. 107) goodness of fit the degree to which an individu- al’s temperament is compatible with the demands and expectations of his or her social environment (p. 409) guided participation a process in which more knowledgeable individuals organize activities in ways that allow less knowledgeable people to learn (p. 155) habituation a simple form of learning that in- volves a decrease in response to repeated or con- tinued stimulation (p. 54) heritability a statistical estimate of the propor- tion of the measured variance on a trait among individuals in a given population that is attrib- utable to genetic differences among those indi- viduals (p. 102) heritable refers to any characteristics or traits that are influenced by heredity (p. 99) heterozygous having two different alleles for a trait (p. 92) holophrastic period the period when children begin using the words in their small productive vocabulary one word at a time (p. 234) homozygous having two of the same allele for a trait (p. 92) hostile attributional bias in Dodge’s theory, the tendency to assume that other people’s ambiguous actions stem from a hostile intent (p. 358) hypotheses educated guesses (p. 23) id in psychoanalytic theory, the earliest and most primitive personality structure. It is un- conscious and operates with the goal of seeking pleasure. (p. 343) G L O S S A R Y n G-5 identical twins twins that result from the split- ting in half of the zygote, resulting in each of the two resulting zygotes having exactly the same set of genes (p. 47) identity achievement an integration of various aspects of the self into a coherent whole that is stable over time and across events (p. 446) identity-achievement status a category of iden- tity status in which, after a period of exploration, the individual has achieved a coherent and con- solidated identity based on personal decisions re- garding occupation, ideology, and the like. The individual believes that these decisions were made autonomously and is committed to them. (p. 448) identity confusion an incomplete and some- times incoherent sense of self that often oc- curs in Erikson’s stage of identity versus identity confusion (p. 446) identity-diffusion status a category of iden- tity status in which the individual does not have firm commitments and is not making progress toward them (p. 447) identity foreclosure premature commitment to an identity without adequate consideration of other options (p. 447) identity versus identity confusion the psycho- social stage of development, described by Er- ikson, that occurs during adolescence. During this stage, the adolescent or young adult either develops an identity or experiences an incomplete and sometimes incoherent sense of self. (p. 446) imaginary audience the belief, stemming from adolescent egocentrism, that everyone else is fo- cused on the adolescent’s appearance and be- havior (p. 444) imprinting a form of learning in which the young of some species of newborn birds and mammals become attached to and follow adult members of the species (usually their mother) (p. 363) incremental/mastery orientation a general tendency to attribute success and failure to the amount of effort expended and to persist in the face of failure (p. 359) incremental theory a theory that a person’s in- telligence can grow as a function of experience (p. 360) independent variable the experience that children in the experimental group receive and that children in the control group do not receive (p. 31) infant-directed speech (IDS) the distinctive mode of speech that adults adopt when talking to babies and very young children (p. 223) infant mortality death during the first year after birth (p. 74) information-processing theories a class of theories that focus on the structure of the cog- nitive system and the mental activities used to deploy attention and memory to solve problems (p. 145) ingroup assimilation process whereby indi- viduals are socialized to conform to the group’s norms, demonstrating the characteristics that define the ingroup (p. 603) insecure attachment a pattern of attachment in which infants or young children have a less positive attachment to their caregiver than do securely attached children. Insecurely attached children can be classified as insecure/resistant (ambivalent), insecure/avoidant, or disorga- nized/disoriented. (p. 431) insecure/avoidant attachment a type of inse- cure attachment in which infants or young chil- dren seem somewhat indifferent toward their caregiver and may even avoid the caregiver. In the Strange Situation, they seem indifferent to- ward their caregiver before the caregiver leaves the room and indifferent or avoidant when the caregiver returns. If the infant gets upset when left alone, he or she is as easily comforted by a stranger as by a parent. (p. 431) insecure/resistant (or ambivalent) attachment a type of insecure attachment in which infants or young children are clingy and stay close to their caregiver rather than exploring their environ- ment. In the Strange Situation, insecure/resistant infants tend to get very upset when the caregiver leaves them alone in the room, and they are not readily comforted by strangers. When their care- giver returns, they are not easily comforted and both seek comfort and resist efforts by the care- giver to comfort them. (p. 431) instrumental aggression aggression motivated by the desire to obtain a concrete goal (p. 578) instrumental or operant conditioning learning the relation between one’s own behavior and the consequences that result from it (p. 201) interest filter initial evaluation of information as being personally interesting (p. 602) intermittent reinforcement inconsistent response to the behavior of another person, for example, sometimes punishing an unacceptable behavior and sometimes ignoring it (p. 351) intermodal perception the combining of infor- mation from two or more sensory systems (p. 186) internalization the process of adopting as one’s own the attributes, beliefs, and standards of an- other person (p. 344) internal validity the degree to which effects ob- served within experiments can be attributed to the factor that the researcher is testing (p. 24) internal working model of attachment the child’s mental representation of the self, of at- tachment figure(s), and of relationships in general that is constructed as a result of experiences with caregivers. The working model guides children’s interactions with caregivers and other people in infancy and at older ages. (p. 429) interrater reliability the amount of agreement in the observations of different raters who wit- ness the same behavior (p. 24) intersubjectivity the mutual understanding that people share during communication (p. 159) IQ (intelligence quotient) quantitative mea- sure, typically with a mean of 100 and a stan- dard deviation of 15, used to indicate a child’s intelligence relative to that of other children of the same age (p. 304) joint attention a process in which social part- ners intentionally focus on a common referent in the external environment (p. 159) latency period the fourth stage in Freud’s theory, lasting from age 6 to age 12, in which sexual energy gets channeled into socially ac- ceptable activities (p. 345) lobes major areas of the cortex associated with general categories of behavior (p. 108) longitudinal design a method of study in which the same children are studied twice or more over a substantial length of time (p. 33) long-term memory information retained on an enduring basis (p. 148) low birth weight (LBW) a birth weight of less than 5½ pounds (2500 grams) (p. 76) macrosystem in the bioecological model, the larger cultural and social context within which the other systems are embedded (p. 368) mathematical equality concept that the values on each side of the equal sign must be equiva- lent (p. 333) meiosis cell division that produces gametes (p. 42) menarche onset of menstruation (p. 618) mental model cognitive processes used to rep- resent a situation or sequence of events (p. 325) mesosystem in the bioecological model, the interconnections among immediate, or micro- system, settings (p. 368) meta-analysis statistical technique used to summarize average effect size and statistical G-6 n G L O S S A R Y significance across several research studies (p. 615) metalinguistic knowledge an understanding of the properties and function of language—that is, an understanding of language as language (p. 218) methylation a biochemical process that influ- ences behavior by suppressing gene activity and expression (p. 12) microgenetic design a method of study in which the same children are studied repeatedly over a short period (p. 33) microsystem in the bioecological model, the immediate environment that an individual per- sonally experiences (p. 367) mitosis cell division that results in two iden- tical daughter cells (p. 45) modularity hypothesis the idea that the human brain contains an innate, self-contained language module that is separate from other as- pects of cognitive functioning (p. 250) monocular depth (or pictorial) cues the per- ceptual cues of depth (such as relative size and interposition) that can be perceived by one eye alone (p. 181) moral judgments decisions that pertain to issues of right and wrong, fairness, and justice (p. 564) moratorium status a category of identity status in which the individual is in the phase of ex- perimentation with regard to occupational and ideological choices and has not yet made a clear commitment to them (p. 447) morphemes the smallest units of meaning in a language, composed of one or more phonemes (p. 217) multifactorial refers to traits that are affected by a host of environmental factors as well as ge- netic ones (p. 99) multiple intelligences theory Gardner’s theory of intellect, based on the view that people possess at least eight types of intelli- gence (p. 320) mutation a change in a section of DNA (p. 90) myelination the formation of myelin (a fatty sheath) around the axons of neurons that speeds and increases information-processing abilities (p. 112) myelin sheath a fatty sheath that forms around certain axons in the body and increases the speed and efficiency of information transmis- sion (p. 107) naïve psychology a commonsense level of un- derstanding of other people and oneself (p. 266) narratives descriptions of past events that have the basic structure of a story (p. 245) naturalistic observation examination of ongoing behavior in an environment not controlled by the researcher (p. 26) nature our biological endowment; the genes we receive from our parents (p. 10) negative identity identity that stands in op- position to what is valued by people around the adolescent (p. 447) neglected (peer status) a category of socio- metric status that refers to children or adoles- cents who are infrequently mentioned as either liked or disliked; they simply are not noticed much by peers (p. 537) neural tube a groove formed in the top layer of differentiated cells in the embryo that eventually becomes the brain and spinal cord (p. 47) neurogenesis the proliferation of neurons through cell division (p. 109) neurons cells that are specialized for sending and receiving messages between the brain and all parts of the body, as well as within the brain itself (p. 106) neurotransmitters chemicals involved in com- munication among brain cells (p. 17) non-REM sleep a quiet or deep sleep state characterized by the absence of motor activity or eye movements and more regular, slow brain waves, breathing, and heart rate (p. 70) normal distribution pattern of data in which scores fall symmetrically around a mean value, with most scores falling close to the mean and fewer and fewer scores farther from it (p. 304) norm of reaction all the phenotypes that can theoretically result from a given genotype in re- lation to all the environments in which it can survive and develop (p. 93) numerical equality the realization that all sets of N objects have something in common (p. 289) numerical magnitude representations mental models of the sizes of numbers, ordered along a less-to-more dimension (p. 332) nurture the environments, both physical and social, that influence our development (p. 11) object permanence the knowledge that ob- jects continue to exist even when they are out of view (p. 136) object segregation the identification of sepa- rate objects in a visual array (p. 179) object substitution a form of pretense in which an object is used as something other than itself, for example, using a broom to represent a horse (p. 271) observational learning learning through watching other people and the consequences others experi- ence as a result of their actions (p. 604) occipital lobe the lobe of the cortex that is pri- marily involved in processing visual information (p. 108) Oedipus complex Freud’s term for the con- flict experienced by boys in the phallic period because of their sexual desire for their mother and their fear of retaliation by their father. (The complex is named for the king in Greek my- thology who unknowingly murdered his father and married his mother.) (p. 344) opportunity structure the economic and social resources offered by the macrosystem in the bio- ecological model, and people’s understanding of those resources (p. 606) oppositional defiant disorder (ODD) a dis- order characterized by age-inappropriate and persistent displays of angry, defiant, and irritable behaviors (p. 580) optical expansion a depth cue in which an object occludes increasingly more of the back- ground, indicating that the object is ap- proaching (p. 180) oral stage the first stage in Freud’s theory, oc- curring in the first year, in which the primary source of satisfaction and pleasure is oral activity (p. 343) organizing influences potential result of cer- tain sex-linked hormones affecting brain dif- ferentiation and organization during prenatal development or at puberty (p. 598) overextension the use of a given word in a broader context than is appropriate (p. 234) overlapping-waves theory an information- processing approach that emphasizes the vari- ability of children’s thinking (p. 152) overregularization speech errors in which chil- dren treat irregular forms of words as if they were regular (p. 243) parental-investment theory a theory that stresses the evolutionary basis of many as- pects of parental behavior, including the exten- sive investment parents make in their offspring (p. 365) parental sensitivity an important factor contrib- uting to the security of an infant’s attachment. Pa- rental sensitivity can be exhibited in a variety of G L O S S A R Y n G-7 ways, including responsive caregiving when an in- fant is distressed or upset and engaging in coordi- nated play with the infant. (p. 435) parenting styles parenting behaviors and at- titudes that set the emotional climate in re- gard to parent–child interactions, such as parental responsiveness and demandingness (p. 472) parietal lobe governs spatial processing as well as integrating sensory input with information stored in memory (p. 108) peers people of approximately the same age and status (p. 512) perceived self-efficacy an individual’s beliefs about how effectively he or she can control his or her own behavior, thoughts, and emotions in order to achieve a desired goal (p. 354) perception the process of organizing and inter- preting sensory information (p. 173) perceptual categorization the grouping to- gether of objects that have similar appearances (p. 264) perceptual constancy the perception of objects as being of constant size, shape, color, etc., in spite of physical differences in the retinal image of the object (p. 178) permissive parenting a parenting style that is high in responsiveness but low in demanding- ness. Permissive parents are responsive to their children’s needs and do not require their chil- dren to regulate themselves or act in appropriate or mature ways. (p. 474) personal fable a form of adolescent egocen- trism that involves beliefs in the uniqueness of one’s own feelings and thoughts (p. 443) personal judgments decisions that refer to ac- tions in which individual preferences are the main consideration (p. 564) phallic stage the third stage in Freud’s theory, lasting from age 3 to age 6, in which sexual plea- sure is focused on the genitalia (p. 344) phenotype the observable expression of the genotype, including both body characteristics and behavior (p. 88) phenylketonuria (PKU) a disorder related to a defective recessive gene on chromosome 12 that prevents metabolism of phenylalanine (p. 93) phonemes the elementary units of meaningful sound used to produce languages (p. 217) phonemic awareness ability to identify com- ponent sounds within words (p. 322) phonological development the acquisition of knowledge about the sound system of a lan- guage (p. 217) phonological recoding skills ability to trans- late letters into sounds and to blend sounds into words; informally called sounding out (p. 322) phylogenetic continuity the idea that because of our common evolutionary history, humans share many characteristics, behaviors, and de- velopmental processes with other animals, espe- cially mammals (p. 47) placenta a support organ for the fetus; it keeps the circulatory systems of the fetus and mother separate, but as a semipermeable membrane permits the exchange of some materials be- tween them (oxygen and nutrients from mother to fetus and carbon dioxide and waste products from fetus to mother) (p. 48) plasticity the capacity of the brain to be af- fected by experience (p. 114) polygenic inheritance inheritance in which traits are governed by more than one gene (p. 93) popular (peer status) a category of socio- metric status that refers to children or ado- lescents who are viewed positively (liked) by many peers and are viewed negatively (dis- liked) by few peers (p. 534) positive reinforcement a reward that reliably follows a behavior and increases the likelihood that the behavior will be repeated (p. 201) pragmatic cues aspects of the social context used for word learning (p. 237) pragmatic development the acquisition of knowledge about how language is used (p. 218) preferential-looking technique a method for studying visual attention in infants that involves showing infants two patterns or two objects at a time to see if the infants have a preference for one over the other (p. 174) premature any child born at 35 weeks after conception or earlier (as opposed to the normal term of 38 weeks) (p. 76) preoperational stage the period (2 to 7 years) within Piaget’s theory in which children be- come able to represent their experiences in lan- guage, mental imagery, and symbolic thought (p. 135) prereaching movements clumsy swiping movements by young infants toward the general vicinity of objects they see (p. 193) pretend play make-believe activities in which children create new symbolic relations, acting as if they were in a situation different from their actual one (p. 271) primary mental abilities seven abilities proposed by Thurstone as crucial to intelligence (p. 300) private speech the second phase of Vygotsky’s internalization-of-thought process, in which children develop their self-regulation and problem-solving abilities by telling themselves aloud what to do, much as their parents did in the first stage (p. 157) proactive aggression unemotional aggression aimed at fulfilling a need or desire (p. 582) problem solving the process of attaining a goal by using a strategy to overcome an ob- stacle (p. 146) production with regard to language, speaking (or writing or signing) to others (p. 217) prosocial behavior voluntary behavior in- tended to benefit another, such as helping, sharing, and comforting of others (p. 562) prosody the characteristic rhythm, tempo, ca- dence, melody, intonational patterns, and so forth with which a language is spoken (p. 224) psychic energy Freud’s term for the collection of biologically based instinctual drives that he believed fuel behavior, thoughts, and feelings (p. 342) psychosocial moratorium a time-out during which the adolescent is not expected to take on adult roles and can instead pursue activities that may lead to self-discovery (p. 447) puberty developmental period marked by the ability to reproduce and other dramatic bodily changes (p. 618) random assignment a procedure in which each child has an equal chance of being assigned to each group within an experiment (p. 30) rapid eye movement (REM) sleep an ac- tive sleep state characterized by quick, jerky eye movements under closed lids and associated with dreaming in adults (p. 70) rational learning the ability to use prior expe- riences to predict what will occur in the future. (p. 204) reactive aggression emotionally driven, antag- onistic aggression sparked by one’s perception that other people’s motives are hostile (p. 582) recessive allele the allele that is not expressed if a dominant allele is present (p. 92) reciprocal determinism Bandura’s concept that child–environment influences operate in both directions; children are affected by aspects of their environment, but they also influence the environment (p. 354) reciprocated best friendship a friendship in which two children view each other as best or close friends (p. 520) reference in language and speech, the associ- ating of words and meaning (p. 231) G-8 n G L O S S A R Y reflexes innate, fixed patterns of action that occur in response to particular stimulation (p. 189) regulator genes genes that control the activity of other genes (p. 91) rehearsal the process of repeating information multiple times to aid memory of it (p. 151) rejected (peer status) a category of sociometric status that refers to children or adolescents who are liked by few peers and disliked by many peers (p. 535) rejecting-neglecting parenting a disengaged parenting style that is low in both responsive- ness and demandingness. Rejecting-neglecting parents do not set limits for or monitor their children’s behavior, are not supportive of them, and sometimes are rejecting or neglectful. They tend to be focused on their own needs rather than their children’s needs. (p. 474) relational aggression a kind of aggression that involves excluding others from the social group and attempting to do harm to other people’s re- lationships; it includes spreading rumors about peers, withholding friendship to inflict harm, and ignoring peers when angry or frustrated or trying to get one’s own way (p. 535) reliability the degree to which independent measurements of a given behavior are consistent (p. 24) role taking being aware of the perspective of another person, thereby better understanding that person’s behavior, thoughts, and feelings (p. 357) rumination a perseverative focus on one’s own negative emotions and on their causes and con- sequences, without engaging in efforts to im- prove one’s situation (p. 396) scale error the attempt by a young child to perform an action on a miniature object that is impossible due to the large discrepancy in the rel- ative sizes of the child and the object (p. 196) scientific method an approach to testing be- liefs that involves choosing a question, formu- lating a hypothesis, testing the hypothesis, and drawing a conclusion (p. 23) script typical sequence of actions used to or- ganize and interpret repeated events, such as eating at restaurants, going to doctors’ appoint- ments, and writing reports (p. 329) secular trends marked changes in physical de- velopment that have occurred over generations (p. 120) secure attachment a pattern of attachment in which infants or young children have a high- quality, relatively unambivalent relationship with their attachment figure. In the Strange Sit- uation, a securely attached infant, for example, may be upset when the caregiver leaves but may be happy to see the caregiver return, recovering quickly from any distress. When children are se- curely attached, they can use caregivers as a se- cure base for exploration. (p. 431) secure base refers to the idea that the presence of a trusted caregiver provides an infant or tod- dler with a sense of security that makes it pos- sible for the child to explore the environment (p. 428) selective attention the process of intentionally focusing on the information that is most rele- vant to the current goal (p. 151) self a conceptual system made up of one’s thoughts and attitudes about oneself (p. 439) self-conscious emotions emotions such as guilt, shame, embarrassment, and pride that re- late to our sense of self and our consciousness of others’ reactions to us (p. 392) self-discipline ability to inhibit actions, follow rules, and avoid impulsive reactions (p. 307) self-esteem one’s overall evaluation of the worth of the self and the feelings that this evalu- ation engenders (p. 458) self-locomotion the ability to move oneself around in the environment (p. 194) self-socialization the idea that children play a very active role in their own socialization through their activity preferences, friendship choices, and so on (p. 356) self-socialization with regard to gender de- velopment, individuals’ use of their beliefs, ex- pectations, and preferences to guide how they perceive the world and the actions that they choose (p. 599) semantic development the learning of the system for expressing meaning in a language, in- cluding word learning (p. 217) sensation the processing of basic information from the external world by the sensory recep- tors in the sense organs (eyes, ears, skin, etc.) and brain (p. 173) sensitive period the period of time during which a developing organism is most sensitive to the effects of external factors; prenatally, the sensi- tive period is when the fetus is maximally sensitive to the harmful effects of teratogens (p. 57) sensorimotor stage the period (birth to 2 years) within Piaget’s theory in which intelli- gence is expressed through sensory and motor abilities (p. 135) separation anxiety feelings of distress that chil- dren, especially infants and toddlers, experience when they are separated, or expect to be sepa- rated, from individuals to whom they are emo- tionally attached (p. 391) sex chromosomes the chromosomes (X and Y ) that determine an individual’s gender (p. 90) sexual-minority youth young people who ex- perience same-sex attractions and for whom the question of personal sexual identity is often con- fusing and painful (p. 454) sexual orientation a person’s preference in re- gard to males or females as objects of erotic feel- ings (p. 453) small for gestational age babies who weigh substantially less than is normal for whatever their gestational age (p. 76) social comparison the process of comparing aspects of one’s own psychological, behavioral, or physical functioning to that of others in order to evaluate oneself (p. 443) social competence the ability to achieve per- sonal goals in social interactions while simulta- neously maintaining positive relationships with others (p. 401) social conventional judgments decisions that pertain to customs or regulations intended to secure social coordination and social organiza- tion (p. 564) socialization the process through which children acquire the values, standards, skills, knowledge, and behaviors that are regarded as appropriate for their present and future role in their particular culture (p. 411) social referencing the use of a parent’s or other adult’s facial expression or vocal cues to decide how to deal with novel, ambiguous, or possibly threatening situations (p. 417) social scaffolding a process in which more com- petent people provide a temporary framework that supports children’s thinking at a higher level than children could manage on their own (p. 159) social-skills training training programs de- signed to help rejected children gain peer ac- ceptance; they are based on the assumption that rejected children lack important knowledge and skills that promote positive interaction with peers (p. 539) social smiles smiles that are directed at people. They first emerge as early as 6 to 7 weeks of age. (p. 388) sociocultural context the physical, social, cultural, economic, and historical circum- stances that make up any child’s environment (p. 17) sociocultural theories approaches that em- phasize that other people and the surrounding G L O S S A R Y n G-9 culture contribute greatly to children’s develop- ment (p. 155) sociodramatic play activities in which children enact miniature dramas with other children or adults, such as “mother comforting baby” (p. 271) socioeconomic status (SES) a measure of social class based on income and education (p. 19) sociometric status a measurement that reflects the degree to which children are liked or dis- liked by their peers as a group (p. 533) spermarche onset of capacity for ejaculation (p. 618) spines formations on the dendrites of neurons that increase the dendrites’ capacity to form connections with other neurons (p. 111) stage theories approaches that propose that development involves a series of discontinuous, age-related phases (p. 15) standard deviation (SD) measure of the vari- ability of scores in a distribution; in a normal distribution, 68% of scores fall within 1 SD of the mean, and 95% of scores fall within 2 SDs of the mean (p. 304) state level of arousal and engagement in the environment, ranging from deep sleep to intense activity (p. 70) stepping reflex a neonatal reflex in which an infant lifts first one leg and then the other in a coordinated pattern like walking (p. 192) stereopsis the process by which the visual cortex combines the differing neural signals caused by binocular disparity, resulting in the perception of depth (p. 181) Strange Situation a procedure developed by Mary Ainsworth to assess infants’ attachment to their primary caregiver (p. 429) strategy–choice process procedure for se- lecting among alternative ways of solving prob- lems (p. 324) structured interview a research procedure in which all participants are asked to answer the same questions (p. 25) structured observation a method that involves presenting an identical situation to each child and recording the child’s behavior (p. 27) subitizing a perceptual process by which adults and children can look at a few objects and al- most immediately know how many objects are present (p. 290) subordinate level the most specific level within a category hierarchy, such as “poodle” in the an- imal/dog/poodle example (p. 264) sudden infant death syndrome (SIDS) the sudden, unexpected death of an infant less than 1 year of age that has no identifiable cause (p. 61) superego in psychoanalytic theory, the third personality structure, consisting of internalized moral standards (p. 344) superordinate level the most general level within a category hierarchy, such as “animal” in the animal/dog/poodle example (p. 264) swaddling a soothing technique, used in many cultures, that involves wrapping a baby tightly in cloths or a blanket (p. 73) symbolic numbers numbers expressed orally or in writing, such as “7” or “seven” (p. 332) symbolic representation the use of one object to stand for another (p. 138) symbols systems for representing our thoughts, feelings, and knowledge and for communicating them to other people (p. 216) synapses microscopic junctions between the axon terminal of one neuron and the dendritic branches or cell body of another (p. 107) synaptic pruning the normal developmental process through which synapses that are rarely activated are eliminated (p. 113) synaptogenesis the process by which neurons form synapses with other neurons, resulting in trillions of connections (p. 112) syntactic bootstrapping the strategy of using the grammatical structure of whole sentences to figure out meaning (p. 239) syntactic development the learning of the syntax of a language (p. 218) syntax rules in a language that specify how words from different categories (nouns, verbs, adjectives, and so on) can be combined (p. 218) systematic desensitization a form of therapy based on classical conditioning, in which positive responses are gradually conditioned to stimuli that initially elicited a highly negative response. This approach is especially useful in the treatment of fears and phobias. (p. 350) task analysis the research technique of identi- fying goals, relevant information in the environ- ment, and potential processing strategies for a problem (p. 146) telegraphic speech the term describing chil- dren’s first sentences that are generally two- word utterances (p. 242) temperament constitutionally based individual differences in emotional, motor, and attentional reactivity and self-regulation that demonstrate consistency across situations, as well as relative stability over time (p. 403) temporal lobe the lobe of the cortex that is as- sociated with memory, visual recognition, and the processing of emotion and auditory infor- mation (p. 108) teratogen an external agent that can cause damage or death during prenatal development (p. 57) test–retest reliability the degree of similarity of a child’s performance on two or more occa- sions (p. 24) theory of mind an organized understanding of how mental processes such as intentions, de- sires, beliefs, perceptions, and emotions influ- ence behavior (p. 267) theory of mind module (TOMM) a hypoth- esized brain mechanism devoted to under- standing other human beings (p. 269) theory of successful intelligence Sternberg’s theory of intellect, based on the view that in- telligence is the ability to achieve success in life (p. 321) third-variable problem the concept that a correlation between two variables may stem from both being influenced by some third vari- able (p. 29) three-stratum theory of intelligence Carroll’s model that places g at the top of the intelligence hierarchy, eight moderately general abilities in the middle, and many specific processes at the bottom (p. 300) transgender a person whose gender identity does not match the person’s genetic sex; includes individuals who identify either with the other sex, with both sexes, or with neither sex. (p. 599) tuition learning through direct teaching (p. 603) umbilical cord a tube containing the blood ves- sels connecting the fetus and placenta (p. 48) unconditioned response (UCR) in classical conditioning, a reflexive response that is elicited by the unconditioned stimulus (p. 201) unconditioned stimulus (UCS) in classical conditioning, a stimulus that evokes a reflexive response (p. 201) Universal Grammar a proposed set of highly abstract, unconscious rules that are common to all languages (p. 248) validity the degree to which a test measures what it is intended to measure (p. 24) variables attributes that vary across individuals and situations, such as age, sex, and popularity (p. 28) vicarious reinforcement observing someone else receive a reward or punishment (p. 352) G-10 n G L O S S A R Y victimized (peer status) with respect to peer re- lationships, this term refers to children who are targets of their peers’ aggression and demeaning behavior (p. 542) violation-of-expectancy a procedure used to study infant cognition in which infants are shown an event that should evoke surprise or interest if it violates something the infant knows or assumes to be true (p. 206) visual acuity the sharpness of visual discrimi- nation (p. 174) visually based retrieval proceeding directly from the visual form of a word to its meaning (p. 324) voice onset time (VOT) the length of time between when air passes through the lips and when the vocal cords start vibrating (p. 225) Wechsler Intelligence Scale for Children (WISC) widely used test designed to measure the intelligence of children 6 years and older (p. 302) withdrawn-rejected children a category of so- ciometric status that refers to rejected children who are socially withdrawn, wary, and often timid (p. 536) word segmentation the process of discovering where words begin and end in fluent speech (p. 228) working memory memory system that involves actively attending to, gathering, maintaining, storing, and processing information (p. 147) zygote a fertilized egg cell (p. 44) R-1 Addy, S., Engelhardt, W., & Skinner, C. 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04.071

NI-1
Bandura, A., 352–356, 380, 594,
603, 613, 622
Banerjee, M., 420
Banerjee, R., 603
Banich, M. T., 107, 118
Bank, L., 483, 585
Banks, M. S., 174, 175
Barbaresi, W. J., 371
Barber, B. K., 474
Barber, B. L., 458
Barchia, K., 582
Barden, R. C., 419
Bardi, L., 178
Bar-Haim, Y., 177
Barker, E., 396
Barker, E. D., 542
Barkley, R. A., 370
Barnard, K. E., 78
Barnes, J., 477, 502
Barnes, J. C., 528, 587
Barnes, M. A., 335
Baron, A. S., 348
Baron-Cohen, S., 269, 270, 363
Barr, C. S., 403
Barr, R., 203, 204
Barr, R. G., 73, 74
Barratt, M. S., 80
Barraza, V., 403
Barrett, K. C., 393
Barrett, L. F., 398
Barrett, P. M., 395
Barrett, T., 164, 193
Barry, R. A., 410, 437
Bartlett, E., 236
Bartlett, N. H., 599
Barton, M. E., 237
Bartrip, J., 12
Bartsch, K., 268
Bascoe, S. M., 483
Bassen, C. R., 594
Batal, H. A., 61
Bates, E., 441
Bates, J. E., 11, 17, 311, 389,
403–407, 409, 501, 581, 586
Bates, L., 486
Bathurst, K., 498
Battistich, V., 576
Baudonnière, P.-M., 440, 514
Bauer, P. J., 203, 280, 347
Bauminger, N., 519
Baumrind, D., 473, 474
Bauserman, R., 493
Name Index
Abbey, B. B., 420
Abela, J. R., 396, 397
Abelson, P., 122
Aber, J. L., 372
Aboud, F. E., 519, 524
Abramovitch, R., 578
Abramson, L. Y., 396
Achenbach, T. M., 78
Acredolo, C., 284, 288
Acredolo, L. P., 248
Adams, B., 577
Adams, E., 582
Adams, G., 378
Adams, M. J., 324
Adams, R. E., 471, 518
Adams, R. J., 175
Adamson, L. B., 159
Addy, S., 80
Adler, S. A., 287
Adler-Baeder, F., 496
Adolph, K. E., 162, 166, 191,
193, 195–197, 200, 284
Afifi, T. D., 490
Agatston, P. W., 529
Aguilar, B., 579
Ahmeduzzaman, M., 483
Ahn, H.-J., 534
Aikins, J. W., 531
Ainsworth, M. D. S., 439
Akhtar, N., 159, 237
Aksan, N., 389, 393, 479, 567
Albareda-Castellot, B., 222
Alberman, E., 94
Albert, D., 400
Alder, R. J., 580
Alessandri, S. M., 73, 202, 388,
392
Alexander, G. M., 599
Alexander, K. L., 313
Alibali, M. W., 333
Alink, L. R. A., 578, 584
Allard, L., 274
Allen, J. P., 347, 522, 586
Alleyne, E., 528
Almeida, D. M., 612
Almquist, Y., 541
Alonso-Alberca, N., 418
Als, H., 365–366
Altamura, M., 538
Altenhofen, S., 491
Altermatt, E. R., 524
Altshuler, J. L., 401
Alwin, D. F., 479
Aman, C., 254
Amaral, D. G., 270
Amato, P. R., 489, 490, 492–
495
American Academy of Pediatrics,
504
American Association of
University Women, 612,
631
American Psychiatric Association,
580, 598
American Psychological
Association, 481
Amso, D., 149, 283
Anderson, C. A., 355, 372, 374
Anderson, K. J., 614, 622, 628
Anderson, M. E., 61
Anderson, R. C., 327
Anderson, V., 118
Andre, T., 624
Andreasen, G., 286
Andrews, D. W., 524
Andrews, S., 265, 266
Angier, N., 597
Anglin, J. M., 246
Angold, A., 395
Ansari, D., 289
Anthis, K. S., 448
Anthony, J. L., 324, 326
Aptekar, L., 481
Aquan-Assee, J., 485
Aram, D., 323
Archer, J., 583, 597, 616, 622,
628, 629, 632
Arcus, D., 406
Arduini, D., 52
Arim, R. G., 584
Aristotle, 8, 36, 41, 42
Armenta, B. E., 573
Armer, M., 537
Armstrong, H. D., 453
Arndorfer, C., 524
Arneson, J. J., 307
Arnett, J. J., 471
Arnold, S. L., 73
Aronoff, J., 631
Aronson, E., 161, 554
Aronson, S. R., 498
Arriaga, R. I., 292
Arsenault, L., 583
Arsenio, W. F., 582, 629
Arterberry, M. E., 173, 175, 181
Asbury, K., 575
Asendorpf, J. B., 440, 540
Ashcraft, M. H., 332, 334
Asher, S. R., 518, 520, 538–541
Ashman, S. B., 407
Ashmead, D., 193
Aslin, R. N., 111, 175, 180, 200,
223, 226, 228, 229, 232, 251
Asquith, P., 565
Astington, J. W., 269, 271
Atkinson, L., 545
Atran, S., 277
Attanucci, J., 561
Attili, G., 539, 540
Audley-Piotrowski, S., 535
Auerbach, R. P., 396, 397
August, D., 222
August, G. J., 470
Augustine, St., 286
Austin, S. B., 457
Awong, T., 460
Ayduk, O., 149, 384
Ayres, M. M., 626
Azmitia, M., 519
Bachman, H. J., 395, 471
Backscheider, A. G., 275, 277
Baer, D. M., 352
Bagès, C., 624
Bagwell, C. L., 518, 521
Baham, M. E., 485
Bahrick, H. F., 148
Bahrick, L. E., 417
Bailey, D. H., 333
Bailey, J., 453
Bailey, J. M., 497
Baillargeon, R., 130, 144, 180,
206–208, 211, 263
Baio, J., 95
Bakeman, R., 159
Baker, J. K., 411
Baker, R. K., 237
Baker, S. T., 149
Bakermans-Kranenburg, M. J.,
98, 377, 410, 437
Balcomb, F. K., 201
Baldwin, D. A., 159, 237
Ball, W., 181
Bámaca, M. Y., 462
Bamford, C., 419
Banaji, M. R., 348

NI-2 n N A M E I N D E X
Bradley, R. H., 310, 311, 317, 479
Bradley, S. J., 598
Braeges, J. L., 564
Braine, M. D. S., 242
Bramlett, M. D., 487–489
Branje, S. J. T., 518, 522
Brannon, E. M., 287, 289, 293
Branstetter, S. A., 522
Brasel, J. A., 120
Braungart-Rieker, J. M., 390, 392
Braver, S. L., 491
Bray, J. H., 495, 496, 522
Brazelton, T. B., 78
Breazeal, C. L., 340, 379
Brechwald, W. A., 521
Breitkreuz, R., 470
Bremner, J. G., 284, 286
Brendgen, M., 33, 521, 542, 586
Brennan, P. A., 396
Brenner, E. M., 400
Brescoll, V., 585
Bretherton, I., 419, 493, 567
Bridges, L. J., 399, 437
Bridges, M., 489, 491
Brody, G. H., 483, 484
Brody, N., 305, 315
Broidy, L. M., 579
Bronfenbrenner, U., 17, 308,
366–368, 379, 380, 469, 606
Bronson, G. W., 390
Brooks, R., 159
Brooks, V., 183
Brooks-Gunn, J., 77, 184, 440,
486, 487, 498, 500, 503, 618
Brophy, J. E., 21
Brophy-Herb, H. E., 412, 414,
548
Broughton, J., 444
Brown, A. L., 161
Brown, A. S., 65
Brown, B. B., 527, 586
Brown, C. S., 603, 610–612, 631
Brown, E., 178
Brown, J., 411
Brown, J. L., 125
Brown, J. R., 413
Brown, R., 242, 243
Brown, R. W., 239
Brown, S. L., 490
Brownell, C. A., 196, 514, 570
Brownell, K., 123
Brownell, K. D., 123, 124
Bruck, M., 4, 5, 254
Brumariu, L. E., 437
Bruner, J., 230
Bruner, J. S., 159, 230, 245
Bruschi, C. J., 396
Bryan, J. B., 243
Bryan, J. H., 574
Bryant, J. A., 529
Block, J., 493
Block, J. H., 493
Bloom, L., 236, 245, 250
Bloom, P., 210, 236, 251
Blue, J., 373
Blume, J. D., 64
Boag, S., 495, 496
Boas, D. A., 220
Bode, L., 65
Boden, J. M., 458, 460
Bohlin, G., 411, 545
Bohon, C., 397
Boiger, M., 386
Boismier, J. D., 71
Boivin, M., 543
Bokhorst, C. L., 518
Boland, A. M., 160
Bolger, K. E., 372, 503
Bolkan, C., 474
Bonica, C., 578
Bonner, J. T., 364
Bono, M., 74
Book, A. S., 583
Booth, A., 477
Booth, J. L., 154, 332, 333
Booth-LaForce, C., 411, 437,
536, 537, 545
Borch, C., 524
Borelli, J. L., 411, 438
Borge, A. I. H., 502
Borke, H., 418
Borker, R., 611
Borneman, M. J., 307
Bornstein, M. H., 52, 175, 271,
272, 479, 483
Boroditsky, L., 283
Borstelmann, L. J., 8
Bortfeld, H., 220, 229
Borton, R. W., 187
Bos, H. M. W., 457, 497
Bosma, H. A., 449
Bouchard, C., 617
Bouchard, T. J., Jr., 99, 101, 309,
312
Boudreau, J. P., 186
Bouffard, T., 442
Boulton, M. J., 397
Boutwell, B. B., 584
Bower, T. G. R., 187
Bowerman, M., 234, 242
Bowker, A., 537, 540
Bowker, J. C., 458, 536, 537
Bowlby, J., 10, 363, 392, 438, 439,
460, 464
Boxer, A., 456
Boyle, M. H., 580
Bozett, F. W., 497
Braaksma, M. A. H., 330
Bradbard, M. R., 601
Bradley, L., 324
Bernd, E., 487
Berndt, T. J., 518, 586
Berninger, V. W., 328, 329
Beron, K. J., 533
Berrill, K. T., 457
Bersani, B. E., 481
Bersoff, D. M., 564, 565
Bertelletti, I., 332
Bertenthal, B. I., 178, 191–193,
195, 267, 284
Berthier, N. E., 193, 285
Besinger, R. E., 76
Best, C. T., 224
Best, D. L., 608
Best, K. M., 80
Betts, N. T., 515
Betz, J. C., 220
Beyer, S., 499
Beyers, W., 448
Bezdjian, S., 583
Bhanot, R., 452, 462, 622
Bialystok, E., 222, 328
Bidell, T. R., 15, 164, 166
Biederman, J., 409, 580
Biehle, S. N., 482
Bierman, K. L., 517, 538
Biernat, M., 608
Bigbee, M. A., 630
Bigelow, B. J., 515, 516
Bigler, R. S., 601–604, 608,
610–612
Binet, A., 298, 301, 336
Birch, E., 181
Birch, H. G., 403
Birch, L. L., 122
Bird, A., 414
Biringen, Z., 491
Bisanz, J., 331
Bissell, J., 483
Bjerregaard, B., 528
Bjorklund, D. F., 153, 363–365,
594, 596
Björkqvist, K., 628
Blachman, B. A., 117
Black, J. E., 115
Black, R. E., 124
Black, S. E., 76
Blackwell, L. S., 22, 360
Blair, C., 17, 149, 300, 313, 335,
407
Blair, K. A., 401
Blais, J. J., 529
Blakeslee, S., 492, 494
Blandon, A. Y., 412
Blanton, H., 521
Blasi, A., 561
Blass, E. M., 46, 74, 202
Blauw-Hospers, C. H., 166
Bleeker, M. M., 623
Blizzard, R. M., 120
Bavelier, D., 115
Beach, S. R. H., 478
Beadman, M., 587
Beardsall, L., 21, 413
Beatty, A. S., 307
Beauchaine, T. P., 406
Beauchamp, G. K., 53, 55, 122
Beaulieu, D. A., 373
Beaver, K. M., 528, 587
Beck, A. T., 397
Becker, B. E., 378
Becker, B. J., 493
Becker, J. B., 453
Becker-Stoll, F., 411
Beckett, C., 7
Becnel, J. N., 520
Bedny, M., 116
Beeghly, M., 419
Behl-Chadha, G., 263
Behne, T., 231
Behnke, A. O., 460, 461
Behrend, D. A., 244
Beijersbergen, M. D., 439
Beilock, S. L., 334, 335
Bekkering, H., 203
Belin, P., 220
Bell, N. J., 617
Belsky, J., 368, 371, 377, 395, 409,
410, 439, 478, 489, 501–504,
546, 613
Bem, D. J., 542
Bem, S. L., 603
Benbow, C. P., 306
Bendersky, M., 389, 390
Benedict, R., 393
Benenson, J. F., 520, 526, 629,
630
Benin, M., 489
Benner, A. D., 480
Bennett, D. S., 389, 390
Bennett, N. G., 76
Benson, B., 486
Benson, J. B., 290
Berardi, N., 116
Bereiter, C., 330
Berenbaum, S. A., 421, 598, 599
Berg, C. A., 153, 400, 626
Berg, N. E., 557
Bergelson, E., 232
Berger, A., 400, 406
Berger, L. M., 490, 498
Berger, S. E., 162, 166, 284
Berger, S. H., 495, 496
Bergman, T., 97, 175
Berk, L. E., 157
Berkel, C., 452
Berko, J., 243
Berman, J. M. J., 246
Bernal, M. E., 450, 451, 573
Bernard, K., 438

N A M E I N D E X n NI-3
Chomsky, N., 247–250, 252, 257
Chouinard, M. M., 265
Christakis, D. A., 240
Christakos, A., 520, 630
Christensen, K. J., 575
Christensson, K., 486
Christian, R. E., 582, 585
Christiansen, M. H., 228
Chudowsky, N., 161
Chugani, H. T., 7
Chung-Hall, J., 539, 540
Church, J., 244
Church, J. A., 326
Church, R. B., 334
Churchill, W., 21
Cianciolo, A. T., 307
Ciano-Federoff, L. M., 481
Ciarrochi, J., 461
Cicchetti, D., 370, 372, 395, 412,
589
Cillessen, A. H. N., 524, 534–536
Cimpian, A., 265
Cismaresco, A. S., 73
Clamp, M., 88
Clark, A. G., 397
Clark, C. A. C., 403
Clark, E. V., 233, 243
Clark, L. V., 357
Clarke-McLean, J. G., 524
Clarke-Stewart, K. A., 437, 489,
498, 500, 578
Clary, E. G., 574, 575
Clausen, S. E., 282
Claxton, L. J., 194
Clearfield, M. W., 165, 289, 290
Cleaves, W. T., 182
Clifton, R. K., 191–193, 195, 206
Clingempeel, W. G., 105, 369
Clore, G., 216
Closson, L. M., 535
Coe, C. L., 59
Cohen, G. L., 521
Cohen, J., 615, 616
Cohen, K. M., 453, 454
Cohen, L., 574, 604
Cohen, L. B., 264, 279, 290
Cohen, N., 312, 313
Cohen, R., 535
Cohen, R. A., 75
Cohn, J. F., 202
Coie, J. D., 394, 533, 535, 537,
539, 541–543, 578, 579, 586
Coker, T. R., 457
Colby, A., 558–560
Coldwell, J., 484
Cole, 396
Cole, A., 545
Cole, D. A., 395
Cole, P. M., 392, 393, 396, 397,
415, 419, 421
Cassidy, J., 347, 437, 460, 536
Castro, D. C., 222
Cattell, R. B., 299
Cauffman, E., 521
Caygill, L., 608
Ceballo, R., 480
Ceci, S. J., 4, 5, 152, 301, 307, 313
Center for Behavioral Health
Statistics and Quality, 395,
396
Centers for Disease Control, 60,
63, 95, 119, 121, 270
Central Intelligence Agency, 75
Cerankosky, B. C., 375
Chabris, C. F., 309
Chall, J., 322–323, 337
Chalmers, D., 155
Chamberlain, B., 524
Chambers, C. G., 246
Chamorro-Premuzic, T., 307
Champagne, F. A., 12
Chan, A., 520
Chan, R. W., 496, 497
Chandler, M. J., 557
Chandra, A., 485
Chang, L., 476, 526
Changeux, J. P., 114
Chao, R. K., 476
Charlesworth, W. R., 629
Chase-Lansdale, P. L., 486, 487,
489, 502
Chatham, C. H., 149
Chaudhary, N., 573
Chayer, M.-H., 442
Chazan-Cohen, R., 320
Cheah, C., 415
Cheah, C. S. L., 476
Cheatham, C. L., 403
Cheek, N. H., Jr., 526
Chen, C., 368, 531
Chen, D., 578
Chen, E., 20
Chen, E. C. H., 394, 415
Chen, F., 570
Chen, F. S., 437
Chen, K., 508
Chen, X., 460, 479, 524, 526,
539, 540
Chen, Z., 150, 153, 158, 280, 281
Cheney, D. L., 219
Cheong, P. H., 529
Cheour, M., 71
Cherlin, A. J., 485, 486, 489, 496
Cherney, I. D., 609, 616, 632
Chess, S., 403–404, 406, 409
Chi, M. T. H., 152
Chiandetti, C., 185
Child Trends, 60
Chisolm, J. S., 73
Choi, S., 234
Caldwell, M. S., 461
Calkins, S. D., 406, 409, 545
Call, J., 219
Callaghan, T., 183, 254, 269
Callanan, M. A., 265, 277
Calvete, E., 582
Calzo, J. P., 455, 456
Camarena, P. M., 614
Cameron, C. E., 149
Camino, C., 564
Camp, C. A, 74
Campbell, A., 608
Campbell, F. A., 79, 318
Campbell, S. B., 202, 395, 578,
581
Campos, J. J., 73, 162, 178, 190,
261, 284, 386, 389, 390, 399,
400, 417, 470, 481
Campos, R., 73
Camras, L. A., 388, 389, 391,
399, 414
Candee, D., 561
Canfield, R. L., 287
Canli, T., 17
Cannon, E. A., 208
Canobi, K. H., 333
Cao, R., 540
Capaldi, D. M., 396, 585, 624
Capizzano, J., 378
Caplan, M., 514
Capozzoli, M. C., 399
Caputi, M., 537, 572
Card, N. A., 578, 616, 628, 631
Cardno, A. G., 11
Cardoso, J. B., 480
Carey, S., 206, 209, 236, 262, 274,
275, 289, 293, 332
Carlo, G., 562, 563, 571, 573, 575
Carlson, C. L., 370
Carlson, E. A., 438
Carlson, S., 285
Carlson, S. M., 271, 273
Carlson, W., 520, 524, 531, 614
Carpenter, M., 159, 570
Carrano, J., 395, 471
Carroll, J. B., 300–302
Carter, C. S., 407
Carter, D. B., 610, 612
Caruso, M., 622
Carver, K., 531
Carver, L. J., 111, 280, 417
Carver, W., 617
Casas, J. F., 535, 578
Casasola, M., 261, 283
Case, R., 143, 314
Casey, B. J., 111, 384
Cashon, C. H., 264, 279
Casiglia, A. C., 540
Caspi, A., 96, 121, 408, 493, 542,
578, 581, 584
Bryant, P., 324
Buchanan, C. M., 453, 490, 496
Buchsbaum, K., 394
Buckner, J. C., 481
Buddin, B. J., 419
Buehler, C., 494, 500, 585
Bugental, D. B., 370, 373, 403,
500
Bugliari, D., 664
Buhrmester, D., 512, 515, 518
Bukowski, W. M., 401, 485, 511,
513, 518, 520, 521, 533, 534,
537, 539, 599
Bulf, H., 178, 200
Bullock, A., 408
Bullock, M., 417, 441
Bumpass, L. L., 486, 489
Bunge, S. A., 149
Burchinal, M. R., 319, 498
Burgess, K. B., 545
Buriel, R., 451, 462, 470, 472,
474, 475, 482, 489, 491, 492,
495
Burkam, D. T., 313, 624
Burke, J. D., 580
Burleson, B. R., 546
Burmeister, D., 518
Burnette, M. L., 583
Burns, T. C., 222
Burrow, A. L., 451
Burt, S. A., 412, 489, 495, 579
Burton, R., 4
Bush, K. R., 476
Bush, N. R., 548
Bushman, B. J., 355
Bushneil, I. W. R., 176
Bushnell, E. W., 186, 193, 200,
286
Buss, D. M., 596
Buss, K. A., 103, 391, 407, 413,
626
Busseri, M. A., 457
Bussey, K., 574, 582, 594, 603,
613, 622
Butcher, L. M., 309
Buttelmann, D., 203
Butterworth, B., 335
Byers-Heinlein, K., 222, 237
Byrd, A. L., 581
Byrnes, J. P., 616, 625
Cahan, S., 312, 313
Cai, H., 463
Cain, K., 325
Cain, K. M., 359
Cairns, R. B., 526, 527, 578
Calati, R., 397
Caldwell, B. M., 310
Caldwell, C. H., 463
Caldwell, K., 540

NI-4 n N A M E I N D E X
Deater-Deckard, K., 97, 410, 475,
476, 583, 584
DeBaryshe, B. D., 624
Debus, R., 442
DeCaro, M. S., 334
DeCasper, A. J., 40, 55
Decker, S. H., 528, 587
Deckner, D. F., 159
Dedmon, S. E., 406
DeFries, J. C., 103, 326
DeGarmo, D. S., 491, 493
Degirmencioglu, S. M., 521, 527
Dehaene, S., 220, 289, 293
Dehaene-Lambertz, G., 220
Dekovic, M., 563, 576
Delaney, C., 73
DeLay, D., 471
Delisi, M., 528, 587
Delius, A., 411
DeLoache, J. S., 98, 183, 196,
198, 216, 241, 252–254
Delsing, M. J. M. H., 527
Deluty, R. H., 582
DelVecchio, W. F., 408
DeMarie-Dreblow, D., 151
Dement, W. C., 71
Demon Dubas, J. J. S., 421
DeMonner, S. M., 64
Dempster, F. N., 149, 151
Denham, S. A., 3, 4, 385, 401,
402, 411–413, 417, 418
Denison, S., 205
Denissen, J. J. A., 472, 479
Dennig, M. D., 401
Dennis, T., 403
Dennis, W., 317
Denny, M. A., 195
Denton, K., 323
Denton, N. A., 19
Depue, R. A., 410
DeRosier, M. E., 540, 543
Derringer, J., 10
Derryberry, D., 408
Désert, M., 624
Desjarlais, M., 529
Desmarais, L. B., 307
DeSnoo, K., 53
Dettling, A. C., 407
Deuchar, M., 222
Deutsch, F. M., 468
Devine, A., 334
DeVos, J., 207
DeVries, M. W., 73
DeWitt, A. L., 605
Di Giorgio, E., 176
Di Giunta, L., 578
Diamantopoulou, S., 397
Diamond, A., 17, 131, 149, 283
Diamond, L. M., 454–457, 531
DiBiase, R., 481
Cumberland, A., 412, 413, 420
Cummings, E. M., 412, 483, 490,
494, 585
Cunningham, A. E., 325
Cunningham, J. A., 451
Curley, J. P., 12
Curry, D., 335
Curtin, S., 228, 241
Curtiss, S., 220
Custodero, L. A., 184
Custrini, R. J., 418
Cutrona, C. E., 487
Dabholkar, A. S., 112, 113
Dahl, A., 462
Dahlström, E., 164
Dale, P. S., 328
Daltabuit, M., 73
Daly, M., 365
Damasio, A. R., 321
Damon, W., 439, 441, 443, 461,
562, 610
Danaher, D. L., 626
Danchin, A., 114
Daniels, D., 105
Dann, S., 510–511
Dannemiller, J. L., 174
Darling, N. E., 368, 475
Darwin, C., 9, 87, 223, 386
Datta, H., 117
D’Augelli, A. R., 456, 457
David, H., 495
Davidson, R. J., 406, 410
Davies, M., 629
Davies, P. T., 395, 412, 483, 490,
494, 531, 584, 585
Davis, B. E., 195
Davis, H. M., 463
Davis, O. S. P., 102, 103
Davis, S. N., 613
Dawson, G., 95, 270
Day, R. D., 575
De, I., 409, 413
de Boysson-Bardies, B., 223, 230,
242
De Brito, S. A., 580
De Goede, I. H. A., 518
de Guzman, M. R. T., 573
de Haan, M., 148, 176, 476
de Heering, A., 115
de Hevia, M. D., 293
de Schonen, S., 12
De Souza, E., 94
De Vries, J. I. P., 51
de Weerth, C., 372
de Wied, M., 581
Deák, G. O., 164
Dearing, E., 475, 504
Dearing, R. L., 393
Deary, I. J., 299, 307
Cortelyou, A., 187
Corter, C., 578
Cortes, R. C., 538
Cortina, K. S., 413
Cosmides, L., 10
Costa, A., 222
Costello, D. M., 396, 397
Costello, E. J., 395
Cota, M. K., 573
Côté, S., 502, 503, 580
Couchoud, E. A., 411, 418
Coulton, C. J., 371
Courage, M. L., 5, 15
Covatto, A. M., 611
Cowan, C. P., 368
Cowan, N., 147, 148
Cowan, P. A., 368
Cox, M. J., 368
Coy, K. C., 27, 394, 470
Coyle, T. R., 33, 153, 299
Coyne, J. C., 412
Coyne, S. M., 628, 632
Craig, W. M., 528, 587
Craighero, L., 204
Craik, F. I. M., 222
Crane, C. C., 268
Craven, R., 442
Crawford, J., 222
Cready, C. M., 605
Cremer, J. F., 155
Crichton, J. A., 387
Crick, F., 88
Crick, N. R., 358, 518, 524, 535,
537, 539, 578, 582, 628, 630,
631
Crisp, V. W., 412
Criss, M. M., 541, 548
Crnic, K., 368, 411, 613
Crocetti, E., 448
Crockenberg, S., 412
Crocker, J., 458, 462
Crockett, L., 526
Crockett, L. J., 474, 630
Croft, C., 411, 438
Crook, P. J., 592
Crooks, C. V., 531
Crosbie-Burnett, M., 497
Crosby, D. A., 502
Crosby, L., 524
Crosnoe, R., 457, 504
Cross, D., 269, 589
Cross, D. R., 160
Crouter, A. C., 471, 477, 625
Crowe, E., 266, 271
Crowley, K., 604, 622
Cruz, J. E., 523
Cruzcosa, M., 373
Csibra, G., 210
Csikszentmihalyi, M., 378
Culp, R. E., 486
Cole, R., 316
Cole, S. W., 11
Cole, W. G., 191
Coleman, C. C., 518
Coleman, H. L., 453
Coleman, M., 538
Coley, J. D., 275
Coley, R. L., 395, 471, 486, 487,
498, 502, 503
Collaer, M. L., 598
Collie, R., 159
Collins, P. F., 403
Collins, W. A., 394, 438, 470,
471, 531, 532
Colombo, J., 199, 287
Coltrane, S., 486, 489
Combs-Ronto, L., 478
Compas, B. E., 401
Compian, L., 396
Compton, K., 483
Comstock, G., 632
Condry, J. C., 630
Conduct Problems Prevention
Research Group, 588–589
Conger, K. J., 482
Conger, R. D., 396, 478, 480,
482, 489, 494, 586
Conley, D., 76
Connell, A., 588
Connell, B., 164
Connell, J. P., 399, 460, 461
Connellan, J., 363
Connelly, B. S., 307
Conner, D. B., 160
Connolly, J., 531
Connolly, J. A., 531
Conroy, S., 74
Consortium for Longitudinal
Studies, 500
Conway, C. C., 588
Conway, M. A., 347
Cook, K. V., 609
Cook, S. W., 333, 334
Cook, W. L., 477
Cooke, M. B., 576
Cooley, C. H., 460
Cooney, T. M., 489
Cooper, R. P., 55, 223
Cooper, S. M., 460, 462
Coplan, R. J., 408, 458, 536,
537
Coppola, M., 248
Corapci, F., 415
Corballis, M., 109
Corbetta, D., 162
Cordaro, D., 386
Cordes, S., 293
Corkill, A. J., 151
Cornell, E. H., 286
Cornwall, A., 323

N A M E I N D E X n NI-5
Evans, J. L., 251
Evans, M. A., 623
Ewart, C. K., 461
Fabes, R. A., 413, 419, 438, 514,
515, 569, 571, 572, 574, 575,
578, 584, 603, 609, 625, 629
Fabricius, W. V., 491
Fagan, J., 487
Fagot, B. I., 487, 600, 603, 604,
611, 613
Falbo, T., 468
Falci, C., 495
Fallang, B., 166
Fantz, R. L., 174
Farber, E. A., 438, 545
Farmer, T. W., 526, 536
Farr, R. H., 497
Farrant, B. M., 575
Farrant, K., 245
Farrar, M. J., 236
Farrell, A. D., 528
Farrington, D. P., 589
Farstad, H., 181
Farver, J., 514, 570, 571
Farver, J. A. M., 583
Favas, E., 220
Feagans, L. V., 500
Fearon, I., 54
Fearon, R. M. P., 438, 439
Feddes, A. R., 524
Federal Bureau of Investigation,
376
Federal Interagency Forum on
Child and Family Statistics,
378, 469, 486, 487
Feeley, T. H., 529
Fegley, S., 446, 574
Feigenson, L., 289
Fein, G. G., 272
Feinberg, M., 484
Feiring, C., 438
Feitelson, D., 327
Feldman, H., 248
Feldman, J. F., 149, 199
Feldman, R., 406, 480, 546, 572,
585
Feldman, R. S., 418
Felice, M. E., 486
Felsman, J. K., 385
Feng, J., 621
Feng, X., 397
Fenning, R. M., 411
Fenson, L., 235, 608
Ferguson, C. J., 632
Fergusson, D. M., 458, 543
Fernald, A., 223, 232–235, 251,
417
Ferrier, L., 231
Ferry, T. R., 625
Eisenbud, L., 613
Eisengart, J., 239
Ekas, N. V., 398
Ekéus, C., 486
Ekman, P., 386
Elbert, T., 116
Elder, G. H., 396, 542
Elicker, J., 544, 545
Elieff, C. A., 181
Elkind, D., 443, 444, 464
Ellerbeck, K., 622
Elliott, D. B., 485
Elliott, D. S., 579, 581
Ellis, B. J., 395, 409, 486
Ellis, R., 494
Ellis, W. E., 531
Ellman, I. M., 491
Ellsworth, C. P., 388
Elman, J. L., 15, 252
Elmore-Staton, L., 494
Else-Quest, N. M., 616, 624, 625,
629
El-Sheikh, M., 406, 494
Ely, R., 246, 620
Emde, R. N., 73, 389
Emery, R. E., 368–370, 489, 493,
523, 585
Engel, S., 272
Engelhardt, W., 80
England, M., 544
Engle, J. M., 413, 518
Englund, M. M., 438
Enns, L. R., 616, 618
Ensor, R., 413
Entwistle, D. R., 313
Eppig, C., 313
Eppler, M. A., 196
Erdley, C. A., 518
Erel, O., 485, 501, 502, 504
Erickson, M. F., 372, 545
Ericsson, K. A., 148
Erikson, E., 341–342, 345–348,
380, 446–447, 449, 451, 460,
464
Erkut, S., 460
Eron, L. D., 579
Esbensen, F.-A., 528
Eslea, M., 632
Espelage, D. L., 526, 629
Espinoza, G., 529
Esposito, G., 74
Espy, K. A., 581
Essex, M. J., 12, 99
Estell, D. B., 526
Etkin, A., 17
Evans, A., 451
Evans, A. D., 32
Evans, E. M., 262, 276
Evans, G. W., 19, 20, 376, 377,
480
Duckett, E., 499
Duckworth, A. L., 307, 401
Dumka, L. E., 585
Duncan, G. J., 149, 154, 314, 328,
335, 504
Dunfield, K., 570
Dunifon, R., 499
Dunkel, C. S., 448
Dunn, J., 21, 272, 389, 394, 411,
413, 483, 484, 513, 514, 519,
544, 571
Dunphy, D. C., 527
Dunsmore, J. C., 385, 411
Duong, M. T., 546
Dupéré, F., 587
Dupoux, E., 210
Durand, C., 230
Durbin, C. E., 392, 408
Duriez, B., 575
Dush, C. M. K., 471
Dutta, R., 522
Dweck, C. S., 21, 22, 357, 359–
362, 380, 437
Dwyer, K. M., 545
Dye, M. W., 115
Dykas, M. J., 536
Eagly, A. H., 597, 607
East, P. L., 486
Eaton, K. L., 412
Eaton, W. O., 51, 103, 616, 618
Ebstein, R. P., 98
Eccles, J. S., 334, 453, 461, 520,
622, 623
Eckenrode, J., 372
Eckerman, C. O., 391
Eckert, P., 527
Eddy, J. M., 539
Edelman, G. M., 114
Eder, D., 533
Edwards, C. P., 18, 522, 573, 607,
609
Edwards, G. D., 468
Egan, V., 587
Egeland, B., 438, 545
Eggum, N. D., 401, 408, 583
Egley, A., Jr., 587
Eiden, R. D., 60, 408, 546
Eigsti, I. M., 384
Eilers, R. E., 230
Eimas, P. D., 225, 226, 263
Einstein, A., 287
Eisenberg, M. E., 124
Eisenberg, N., 393, 395, 401, 402,
408, 409, 412, 413, 417, 418,
420, 438, 476, 478, 524, 534,
535, 542, 546, 562, 563, 567,
569, 571–574, 578, 583, 584,
601, 629
Eisenberg-Berg, N., 562, 613
Dick, D. M., 522
Dickens, W. T., 313, 315
Dickinson, D. K., 235
Dickson, L. R., 416, 417
DiClemente, R. J., 448
Diedrich, F. J., 165
Diekman, A. B., 605, 607
Diener, M., 68
Diener, M. L., 401
Dijkstra, J. K., 524, 534
Dillow, S. A., 619, 621
Dilworth-Bart, J. E., 20
Dinella, L., 397
Ding, Q . J., 468
Dionne, G., 578
DiPietro, J. A., 52, 63, 65, 66,
613, 616
Dirix, C. E., 54
Dishion, T. J., 357, 358, 521, 523,
524, 546, 548, 585–588
Disney, E. R., 63
Diversi, M., 462, 481
DiVitto, B., 78
Dix, T., 575
DiYanni, C., 274
Doan, R. M., 121
Doan, S. N., 401, 480
Dobrova-Krol, N., 437
Dobzhansky, T., 93
Dodge, K. A., 357–358, 361, 380,
394, 533, 534, 537, 539, 578,
579, 582–586, 630
Dodge, T., 521
Dogan, S. J., 584
Dohnt, H., 460
Dombkowski, L., 60
Dominguez, A., 480
Domitrovich, C. E., 538
Donaldson, S. K., 419
Dong, Q ., 479
Donnellan, M. B., 442, 458
Donovan, C. L., 397
Doornwaard, S. M., 527, 528
Doris, J., 372
Dornan, J. C., 62
Dornbusch, S. M., 475, 490
Doussard-Roosevelt, J. A., 406
Dove, H., 191
Dowden, A., 203
Downey, G., 412
Doyle, A. B., 545
Dozier, M., 438
Drabick, D. A. G., 578
Driesen, N. R., 599
Drillien, C. M., 80
Driscoll, A. K., 474
Drummond, K. D., 454
Druyan, S., 143
Dubas, J. S., 471, 472, 482
Dube, E. M., 456

NI-6 n N A M E I N D E X
Gerton, J., 453
Gervai, J., 613
Geschwind, D. H., 95
Gesell, A., 191
Gest, S. D., 533
Gfellner, B. M., 453
Ghazanfar, A. A., 188
Giancola, P. R., 407
Gianino, A., 399
Gibbs, J. C., 560, 575
Gibbs, N., 554
Gibson, E. J., 195–196, 199
Gibson-Davis, C. M., 490
Giedd, J. N., 112, 113
Gilbert, V., 552
Gilbreth, J. G., 492
Gildea, P. M., 246
Giles, J. W., 630
Giletta, M., 520
Gillham, J. E., 397
Gilligan, C., 561
Gillis, J. J., 103
Gingo, M., 560, 565
Gjerde, P. F., 493
Gladwell, M., 307
Glaser, R., 161
Glasper, E., 109
Gleason, J. B., 620, 627
Gleitman, H., 223, 239
Gleitman, L., 223, 239, 248
Glick, G. C., 519
Glick, J., 489
Gnepp, J., 421
Godlee, F., 95
Gogtay, N., 113, 114
Gold, J., 582
Goldberg, S., 78
Goldin-Meadow, S., 248, 333,
334
Goldman-Rakic, P. S., 283
Goldsmith, H. H., 95, 103, 104,
410, 626
Goldstein, M. H., 231, 250
Goldstein, M. J., 477
Goldstein, S. E., 612, 631
Goldstein, T. R., 269
Goldstein, Z., 327
Goleman, D., 385
Golinkoff, R., 242
Golish, T. D., 496
Golombok, S., 497
Golter, B. S., 547
Gómez, R. L., 244
Göncü, A., 159, 483
Gondoli, D. M., 474
Gonzales, N. A., 585
Gonzales-Backen, M., 452
Good, C., 361
Good, T. L., 21
Gooden, A. M., 605
Gamble, W. C., 483
Gamliel, I., 251
Gandelman, R., 53
Ganea, P. A., 183
Ganiban, J. M., 408, 409, 472,
494
Garandeau, C. F., 534
Garbarino, J., 371
Garber, J., 395–397, 421, 535
Garcia, M. M., 484
Garcia, V., 204
Garcia-Coll, C. T., 77
Gardner, B. T., 219
Gardner, D., 420
Gardner, H., 320–322, 336
Gardner, J. M., 63
Gardner, R. A., 219
Gardner, T. W., 528
Gargus, R. A., 77
Garing, A. E., 284
Garmezy, N., 80
Garmon, L. C., 561
Garrett-Peters, P., 479
Gartrell, N., 497
Gartstein, M. A., 400
Gass, K., 483
Gassman-Pines, A., 316, 490
Gathercole, S. E., 147
Gatzke-Kopp, L. M., 579
Gaub, M., 370
Gaunet, F., 285
Gauvain, M., 155, 159, 160
Gavin, L. A., 524, 527
Gaylord-Harden, N. K., 451, 452
Gazelle, H., 536
Ge, X., 396, 478, 489, 491
Gearhart, M., 160
Geary, D. C., 10, 153, 154, 289,
299, 300, 307, 313, 331–333,
335, 363, 364, 594, 596, 598
Gegeo, D. W., 224
Geisheker, E., 574
Gelman, R., 206, 223, 265, 277,
290, 291
Gelman, S. A., 134, 235, 262,
265, 274–277, 604
Genesee, F., 222
Gentner, D., 233, 283
George, C., 372
Gerbner, G., 605
Gergely, G., 203, 210
Gerken, L., 201, 244
Gerken, L. A., 232
German, T. P., 271
Germino-Hausken, E., 323
Gernsbacher, M. A., 95, 159
Gerris, J. R. M., 471, 482
Gershkoff-Stowe, L., 164
Gershoff, E. T., 3, 583, 584
Gertner, Y., 239
Frankenhuis, W. E., 372
Franklin, S., 34, 153
Fraser, C., 242
Fredricksson, Y., 164
Freedman, D. G., 414
Freedman, J., 77
Freedman, N. C., 414
Freedner, N., 631
Freeman, M. S., 55
Freiberg, K., 574
Freitag, M. K., 545
Freitas, G. V. S., 486
French, D. C., 514, 539, 540
French, K. E., 616, 617
French, S. E., 451
Freud, A., 510–511
Freud, S., 10, 15, 36, 341–350,
379, 380, 510, 568
Frey, K. S., 442, 600
Frick, P. J., 582, 585
Fried, P. A., 63
Friedlmeier, W., 415, 421, 572
Friedman, M. A., 124
Friedman, M. S., 457
Friedman, N. P., 149, 400
Friedman, O., 149, 272
Friedman, W. J., 287, 288
Friend, A., 326
Frijda, N. H., 415
Frosch, C. A., 438, 494
Fry, D., 632
Frye, D., 266, 271, 291
Fu, Y., 410
Fuchs, I., 333, 335, 562
Fujisawa, K. K., 571
Fulcher, M., 497
Fuligni, A. J., 453, 468, 471, 522,
528
Fuller-Rowell, T. E., 480
Fung, H., 394, 415
Furman, W., 512, 515, 517, 518,
522, 524, 527, 531, 545
Furnes, B., 23
Furstenberg, F. F., 487
Furukawa, E., 393, 394
Gable, S., 613
Gaddis, A., 618
Gådin, K. G., 631
Gaertner, B. M., 482
Gailileo, 184
Gaither, S. E., 177
Galambos, N., 396, 612
Galbraith, K. A., 486
Galen, B. R., 630
Gallese, V., 204
Galliher, R. V., 452, 462
Gallistel, C. R., 291
Galloway, J. C., 166
Galton, F., 87–88, 99
Fetter, M. D., 527
Field, A. E., 618
Field, D., 142
Field, T., 73, 77
Field, T. M., 406
Fielding, L. G., 327
Fields, R. D., 108
Fifer, W. P., 54, 55, 71
Filho, N. M., 481
Fincham, F. D., 412, 490
Fincher, C. L., 313
Fine, M. A., 462, 495
Fine, S. E., 418
Finegan, J.-A. K., 621
Fineran, S., 631
Finkelstein, B. D., 515
Finnie, V., 548
Fischel, J., 219
Fischer, A. R., 463
Fischer, J. L., 527
Fischer, K. W., 15, 164, 166, 392
Fiser, J., 251
Fisher, C., 239
Fisher, D. M., 192
Fisher, J. A., 122
Fisher, P. A., 630
Fisher, S. E., 94
Fitch, R. H., 622
Fivush, R., 160, 245, 415
Flanagan, D. P., 302
Flavell, J. H., 142, 268, 419, 421
Fleetwood-Walker, Bernard, 466
Fletcher, A. C., 368, 524
Flom, R. A., 164
Florsheim, P., 487
Floyd, F. J., 457
Flynn, J. R., 313–315
Flynn, M., 397
Fodor, J. A., 250
Foehr, U. G., 375
Fogel, A., 12, 387
Foley, D. L., 395
Fong, V. L., 468
Fontaine, R. G., 579, 582
Fonteneau, E., 251
Fonzi, A., 515
Forbes, D., 626
Forbes, G. B., 631
Forbes, L. M., 439
Forehand, R., 489
Forssell, S. L., 497
Fosco, G. M., 484
Foster, E. M., 589
Fouad, N. A., 625
Fox, N. A., 78, 406–407, 409, 545
Fraga, M. F., 98
Fraley, R. C., 438, 478
Francis, D. J., 324, 326
Frank, D. A., 63
Frankel, C. B., 399

N A M E I N D E X n NI-7
Hastings, P. D., 409, 413, 571,
575, 576, 582
Hatano, G., 134, 262, 263, 274,
275, 278
Hatzichristou, C., 537, 539
Hauck, F. R., 61
Hauser, M., 289
Hauser, P. C., 115
Hawker, D. S. J., 397
Hawkins, D. N., 492
Hawkins, J. A., 518
Hawley, P. H., 535, 631
Hawley, T. L., 63
Haworth, C. M. A., 102
Hay, D. F., 514, 577, 578, 581,
628, 629
Hay, J. F., 229
Hayes, C., 219
Hayes, K. J., 219
Hayne, H., 159, 203, 204, 347
Hayward, C., 396
He, Y., 460, 526
Heathcock, J. C., 166
Heatherington, L., 457
Heaven, P., 461
Hebb, D. O., 114
Hebl, M., 384
Hecht, S. A., 335
Heckman, J. J., 319
Hedges, L. V., 616, 620, 621
Hegley, D., 389
Heine, S. J., 463, 464
Heinmiller, B. M., 184
Held, R., 181
Hell, B., 307
Helmbrecht, L., 497
Helsen, M., 518
Hembree, E. A., 390, 392
Henkel, R. R., 526
Hennessy, E., 514
Henry, B., 408
Henry, C. S., 575
Henry, D. B., 586
Hepper, P. G., 46, 62
Herald-Brown, S. L., 541
Herbert, J., 203, 514
Herdt, G., 619
Herdt, G. H., 456
Herman, M., 462
Hermans, E. J., 583
Hermer, L., 283
Hernandez, D. J., 19, 485
Hernandez, J. T., 448
Hernández, M., 222
Hernandez-Reif, M., 77
Herrera, C., 372, 417
Herrmann, E., 266
Hershberger, S. L., 456, 457
Hershey, K., 408
Hertenstein, M. J., 390, 417
Halpern-Meekin, S., 495
Halverson, C. F., Jr., 600, 602
Hamaguchi, Y., 518, 539
Hämäläinen, M., 581
Hamamura, T., 464
Hamer, D. H., 453
Hamilton, B. E., 64, 76
Hamilton, C. E., 438
Hamilton, M. C., 605
Hamlin, J. K., 210, 211
Hammen, C., 395, 397
Hammond, M., 538
Han, W.-J., 498, 499
Hand, M., 562
Hanish, L. D., 542, 543, 588,
625
Hankin, B. L., 396
Hanlon, C., 243
Hanna, E., 204
Hannon, E. E., 185
Happaney, K., 370, 373
Harada, M., 57
Harden, K. P., 103, 312, 494
Hardy, C. L., 520
Hardy, J. B., 486
Harger, J., 406
Harkness, S., 72, 73
Harlaar, N., 328
Harlan, E. T., 400
Harley, K., 160
Harlow, H. F., 511
Harman, C., 73
Harold, G. T., 494
Harper, J. M., 483
Harris, E., 554
Harris, F. R., 352
Harris, J. R., 602
Harris, K. M., 487
Harris, K. R., 330
Harris, P. L., 238, 267, 269, 272,
418–421
Harris-Britt, A., 453
Harrison, Y., 72
Harrist, A. W., 536, 537, 539
Hart, B., 235, 479
Hart, C., 124
Hart, C. H., 545–547
Hart, D., 439, 441, 443, 446, 461,
574, 575
Harter, S., 396, 419, 441–446,
453, 458–461, 463, 515
Hartman, L. R., 489
Hartup, W. W., 514, 515, 517,
519, 524, 578
Harvey, E., 499
Harwood, R. L., 565
Hasegawa, T., 571
Haselager, G. J. T., 524, 525
Haskins, R., 317, 501
Hasson, A., 76
Grégoire, J., 332
Gregory, A. M., 397, 572
Grieco-Calub, T. M., 251
Griepentrog, G. J., 200
Griffin, S., 314
Grimshaw, G. M., 621
Groh, A. M., 437, 438
Grolnick, W. S., 399, 437
Grön, G., 621
Gross, D., 420
Gross, J. J., 398
Gross, J. N., 393
Gross, R. T., 80
Grossmann, T., 416, 417
Grotevant, H. D., 449
Grotpeter, J. K., 628
Gruber, J., 631
Grueneich, R., 557
Grusec, J. E., 460, 475, 574, 575,
604
Grych, J. H., 412, 484, 490, 494
Guberman, S. R., 160
Guerin, D. W., 394, 408
Guerra, N. G., 19, 20, 470, 542,
543, 582, 633
Guimond, A. B., 452
Gulko, J., 608, 610
Gummerum, M., 515
Gunnar, M. R., 120, 397, 403, 407
Gunnoe, M. L., 493
Gustafson, G. E., 73
Guthrie, I. K., 535, 569
Guthrie, J. T., 29, 327
Gutman, L. M., 316
Gwiazda, J., 29, 181
Ha, T., 531, 532
Haas, B., 479
Hadders-Algra, M., 166
Haden, C. A., 160
Hafdahl, A. R., 462
Hagekull, B., 411, 545
Hagewen, K. J., 481
Haier, R. J., 300, 314
Haimerl, F., 18
Haine, R. A., 160
Haines, H. M., 67
Hains, S. M., 388
Haith, M. M., 175, 178, 287, 290
Hakak, Y., 108
Hakuta, K., 222
Hakvoort, E. M., 495
Halberstadt, A. G., 385, 411, 412
Halil, T., 73
Hall, D. G., 239
Halligan, S. L., 525
Hallmayer, J., 105
Halpern, C. T., 453
Halpern, D. F., 599, 607, 616,
619–623
Gooden, M. A., 605
Goodenough, F. L., 392
Goodman, G. S., 254
Goodman, S. H., 579, 580
Goodnight, J. A., 580, 585
Goodnow, J. J., 254, 255, 475,
523, 574, 604
Goodwin, P., 485
Goodwyn, S. W., 248
Gooren, E. M. J. C., 539, 541
Goossens, L., 448
Gopnik, A., 234, 268, 269
Gordis, E. B., 480
Gordon, R. A., 587
Gorman-Smith, D., 586
Gosselin, J., 495
Gottesman, I. I., 11, 103, 105
Gottfredson, L. S., 299, 302
Gottfried, A. E., 498, 499
Gottfried, A. W., 394, 408, 498
Gottlieb, A., 41, 191
Gottlieb, G., 103, 365
Gottman, J. M., 413, 516, 517,
519, 526, 546
Goubet, N., 193
Gougoux, F., 115
Gould, E., 109
Gould, S. J., 596
Gove, W. R., 500
Govindan, R. B., 52
Gowen, L. K., 396
Graber, J. A., 618
Graf Estes, K., 229
Graham, S., 543
Graham, S. A., 237, 239, 241,
246, 330, 358
Graham-Bermann, S. A., 585
Graham-Kevan, N., 629
Gralinski, J. H., 392
Grall, T. S., 493
Granger, D. A., 407
Granot, D., 545
Granrud, C. E., 179
Graves, N. B., 573
Graves, T. D., 573
Gray, E., 4
Gray, J. R., 626
Gray-Little, B., 462
Grayson, C., 396
Green, J. A., 73
Green, R. E., 88
Greenberg, M. T., 4, 538, 588
Greenberger, E., 368
Greene, J. G., 78
Greene, M. L., 451, 462, 516
Greenfield, P. M., 18, 19, 376,
463
Greenough, W. T., 115, 116
Greenstein, T. N., 613
Greenwald, A. G., 348

NI-8 n N A M E I N D E X
Jing, Q ., 468
Joanisse, M. F., 283
Jocklin, V., 493
John, R. S., 480, 485
Johnson, A., 53
Johnson, C., 491
Johnson, C. J., 244
Johnson, D. C., 61
Johnson, D. E., 120
Johnson, E. K., 228
Johnson, F. A., 523
Johnson, J., 479
Johnson, J. H., 26
Johnson, J. S., 221
Johnson, K. E., 152
Johnson, M. H., 221, 363
Johnson, M. K., 575
Johnson, S., 209
Johnson, S. C., 209, 276, 437
Johnson, S. L., 122
Johnson, S. P., 177, 179, 180, 193,
200, 251, 261, 283
Johnson, W., 21
Johnston, C., 500
Joiner, T. E., Jr., 397
Jome, L. M., 624
Jones, D. C., 420
Jones, D. E., 589
Jones, K. L., 62
Jones, L. E., 73
Jones, M. C., 350
Jones, M. D., 452, 462
Jones, R. M., 448
Jones, S., 264, 623
Jones, S. S., 239
Jordan, N. C., 290, 333, 335
Jorgensen, M., 618
Joshi, A., 531
Joshi, M. S., 421
Joshi, P. T., 395
Joussemet, M., 581
Jovanovic, J., 622
Joyner, K., 531
Juel, C., 324, 329
Julian, T. W., 476
Jung, R. E., 300
Jusczyk, P. W., 226, 228, 229, 231
Jussim, L., 623
Justice, L. M., 235
Juvonen, J., 543
Kagan, J., 184, 261, 389–391,
406–408
Kahen, V., 546
Kail, R., 150, 151
Kalakanis, L., 177
Kaler, S. R., 77, 400
Kalil, A., 307, 500
Kalish, C. W., 262, 276
Kalmár, M., 80
Hymel, S., 515, 519, 540
Hyvärinen, L., 285
Iacono, W. G., 21, 583
Iglesias, J., 416
Imperato-McGinley, J., 622
Impett, E. A., 461
Inagaki, K., 134, 262, 263, 274,
275
Ingoldsby, E. M., 484
Inhelder, B., 138, 139, 141, 570
Inlow, J. K., 309
Insabella, G. M., 489, 491
Institute of Medicine, 124
Intons-Peterson, M. J., 608
Ispa, J. M., 475, 476
Israel, S., 572
Ito, T., 91
Iverson, J. M., 248
Iyer, R. V., 542
Izard, C. E., 385, 386, 388, 390,
392, 418, 538
Jaakkola, R., 274
Jaccard, J., 521
Jacklin, C. N., 613, 629
Jackson, L. A., 529
Jacobs, J. E., 623
Jacobson, J. L., 62, 63
Jacobson, K. C., 312, 630
Jacobson, L. J., 486
Jacobson, S. W., 62, 63
Jacquet, A.-Y., 53
Jaffee, S. R., 103, 120, 486, 487,
561, 583–585
Jagnow, C. P., 55
Jahromi, L. B., 73, 399, 479
Jakobson, R., 230
James, D., 52
James, S., 493
James, W., 173
Jankowski, J. J., 149
Jansen, P. W., 479
Janssens, J. M. A. M., 563, 576
Jaser, S. S., 401
Jaswal, V. K., 237
Jaycox, L. H., 397, 631
Jegalian, K., 90
Jelalian, E., 124
Jencks, C., 307
Jenkins, E., 34, 153
Jenkins, J., 483, 485
Jenkins, J. M., 271
Jensen, A. C., 483
Jensen, A. R., 299, 318
Jensen, P. S., 371
Jensen-Campbell, L. A., 518
Ji, G., 468
Jiao, S., 468
Jiao, Z., 518
Holliday, H., 627
Holmes, A., 347
Holt, M. K., 526
Homae, F., 220
Honeycutt, H., 597
Honomichl, R., 158
Honorado, E., 548
Hood, L., 245
Hooven, C., 413
Hope, S., 489
Hopf, D., 514, 537, 539
Hopkins, B., 191
Horn, J. L., 300, 302
Horn, S. S., 527
Horne, R. S., 61
Horst, J. S., 164
Horwood, L. J., 458, 543
Hossain, Z., 483
Houston, D. M., 228, 251
Howe, M. L., 5, 15
Howe, N., 474, 485
Howell, J. C., 587
Howes, C., 13, 513, 514, 524,
570, 571, 630
Howes, D., 51
Hoyne, K. L., 241
Hoza, B., 518, 521, 542
Hubbard, F. O. A., 74
Hubbard, M. L., 461
Hudley, C., 358
Hudson, J. A., 153, 245
Huebner, R. R., 388, 390
Huesmann, L. R., 633
Huffman, L. C., 406
Hughes, C., 413, 519
Hughes, D., 451, 524
Huguley, J. P., 453
Huizinga, D., 528, 587
Huizink, A. C., 403
Hume, D., 279
Humphreys, L. G., 299, 305
Hunt, E., 62
Hunt, J. M., 317
Hunter, E., 548
Hunter, F. T., 518
Hunter, J., 307
Hunziker, U. A., 74
Hurles, M., 94
Hurst, S.-L., 578
Hurtado, N., 235
Hurwitz, W. M., 239
Huston, A. C., 372, 498, 605
Hutchins, T., 629
Huttenlocher, J., 235, 283, 286,
289, 290, 313
Huttenlocher, P. R., 112, 113
Hwang, C. P., 483
Hwang, J. M., 529
Hyde, J. S., 561, 615, 616, 619,
620, 624
Hertzman, C., 314
Hertz-Pannier, L., 220
Hesketh, T., 468
Hespos, S. J., 283, 290
Hess, D. L., 421
Hess, R. D., 523
Hetherington, E. M., 105, 369,
484, 485, 489, 491–493, 495,
496
Hewlett, B. S., 414, 613
Heyman, G. D., 630
Hiatt, S. W., 389
Hickling, A. K., 275, 281
Hickman, L. J., 631
Higgins, D. A., 629
Higgins, E. T., 443, 445, 461
Hilden, D., 151
Hilden, K., 327
Hill, E. A., 224
Hill, J., 522
Hill, J. P., 471, 612
Hill, L. G., 586
Hill, N. E., 476
Hill, S. A., 479
Hill-Souderlund, A. L., 390
Hilt, L. M., 396
Hilton, S. C., 66
Hines, M., 598, 599, 621
Hinshaw, S. P., 580
Hipwell, A., 543
Hirshfeld-Becker, D. R., 409
Hirsh-Pasek, K., 13, 242, 272
Hite, T., 613
Hitler, A., 510
Hjern, A., 486
Ho, D. Y. F., 540
Hobson, J. A., 270
Hochberg, J., 183
Hockenberry, S., 577
Hodges, E. V., 518
Hoeksma, J. B., 20
Hoekstra, R. A., 95
Hoeve, M., 438, 474
Hofer, C., 408
Hoff, E., 234, 235, 479
Hoff, K. E., 535, 536
Hoff-Ginsberg, E., 479
Hoffman, C. D., 482
Hoffman, L., 526
Hoffman, L. W., 499, 500
Hoffman, M. L., 267, 393, 397,
412, 475, 557, 567, 569, 572,
575, 584
Hoffmeyer, L. B., 74
Hoffner, C., 401
Hofstede, G., 603
Hoglund, W. L. G., 543
Hogue, A., 525
Holden, C., 101
Holland, C. J., 327

N A M E I N D E X n NI-9
Kuschel, C., 63
Kushnir, T., 204, 205
Kutnick, P., 560
Kutsukake, N., 571
Kwon, K., 526
La Greca, A. M., 394, 527
LaBounty, J., 413
Lacourse, E., 528, 586
Ladd, G. W., 397, 518, 536, 538,
541, 543, 546, 547
LaFreniere, P. J., 545, 629
LaFromboise, T., 453
Lagattuta, K. H., 392, 419, 565
Lagercrantz, H., 67
Lahey, B. B., 578–580, 587
Lahn, B. T., 90
Laible, D. J., 437, 438, 545, 567,
575
Laird, M., 372
Laird, R. D., 471, 547, 585
Lalonde, C. E., 226
Lam, C. B., 471
Lamb, M. E., 5, 438, 486, 501,
503, 504, 594
Lamb, S., 571
Lamborn, S. D., 460, 474, 475
Lampman-Petraitis, C., 394
Landau, B., 94, 239, 264
Lander, E. S., 88, 94
Lando, B., 578
Landry, S. H., 76
Langabeer, K. A., 454, 456
Langer, J., 290
Langlois, J. H., 177, 460, 477,
533
Langrock, A., 412
Lansdale, N. S., 499
Lansford, J. E., 357, 358, 475,
534–537, 541, 543, 582, 584
Lany, J., 244
Largo, R. H., 80
Larkin, J., 631
Larson, J., 396
Larson, J. R., 116
Larson, R., 394, 471
Larson, R. W., 394, 522
Lasky, N., 518
Latendresse, S. J., 378
Laub, J. H., 584
Laumann-Billings, L., 368–370
Laursen, B., 394, 470, 471, 479,
515, 518, 521
Lavelli, M., 12
Lavner, J. A., 457
Lawford, H., 545, 575
Lawrence, J. A., 155
Lazar, I., 317
Le, H.-N., 224
Le Corre, M., 332
Koenig, M. A., 238
Koerner, S. S., 490
Kohatsu, E. L., 451
Kohen, D. E., 480
Kohlberg, L., 15, 555, 558–563,
566, 590, 600
Kolb, B., 108, 113, 117, 118
Kolb, S., 192
Konarski, R., 531
Kopp, C. B., 77, 80, 392, 399,
400, 567
Korat, O., 328
Koren, G., 63
Korenman, S., 314
Körkel, J., 152
Korner, A. F., 73
Kostelny, K., 371
Kotila, L. E., 471
Kotler, J. S., 581
Kotovsky, L., 206
Kouros, C. D., 412
Kovács, Á. M., 222
Kovacs, M., 397
Kovas, Y., 326
Kover, S. T., 335
Kowal, A. K., 484
Kowalski, R. M., 529
Kramer, L., 484
Kramer, M. S., 121
Kramer, S. J., 178
Krascum, R. M., 265, 266
Krause, J. A., 334
Kraut, R., 529
Kreager, D. A., 534
Kreider, R. M., 485, 494
Kreppner, J. M., 7
Kreutzer, T., 438
Krevans, J., 575
Krishnamoorthy, J. S., 124
Kroger, J., 448
Kroupina, M. G., 347
Krueger, A. B., 664
Krueger, R. F., 410
Kruger, A. C., 512
Krull, J. L., 484
Ksansnak, K. R., 610, 612
Kuczaj, S. A., II, 243
Kuczynski, L., 475
Kudo, N., 200
Kuhl, P. K., 110, 187, 223, 226,
227
Kuhn, D., 34, 153
Kumru, A., 563
Kunnen, E. S., 449
Kupersmidt, J. B., 535, 537, 540,
541
Kuppens, S., 474
Kurdek, L. A., 493, 495
Kuryluk, A., 535
Kusché, C. A., 4
Ketterlinus, R. D., 486
Kety, S. S., 11, 105
Keys, T. D., 503
Kiang, L., 452, 453
Kidd, C., 201
Kiel, E. J., 391, 413
Kiernan, K. E., 489
Kiesner, J., 523, 526
Kiff, C. J., 396, 409, 478
Killen, M., 565, 610
Kim, D-Y., 401
Kim, H. K., 396, 397
Kim, I. K., 207
Kim, J-Y., 483, 484
Kim, K. H., 221
Kim, K. J., 409, 412
Kim, S., 438, 583, 584
Kim, S. Y., 480
Kinal, M. P.-A., 442
Kindermann, T. A., 526
King, A. P., 250
King, R. A., 570
King, V., 492, 493, 495
Kingery, J. N., 518
Kintsch, W., 148
Kinzler, K. D., 206, 210
Kipp, K., 151
Kiraly, I., 203
Kiriakidis, S. P., 529
Kirillova, G. P., 407
Kirkham, N., 149
Kirkham, N. Z., 200, 251, 280
Kisilevsky, B., 54
Kitayama, S., 415
Kiuru, N., 526
Klahr, A. M., 584
Klahr, D., 145–146
Klebold, D., 554
Klepac, L., 545
Klima, T., 520
Klimes-Dougan, B., 399, 413
Klin, A., 270
Kling, K. C., 460
Kloos, H., 211
Klowden, A., 548
Klute, C., 527
Knafo, A., 569–572, 575
Knecht, A., 521, 524
Knight, D. K., 160
Knight, G. P., 451, 573, 629
Knowles, L., 286
Knudsen, E. I., 319
Kobak, R., 347
Kobasigawa, A., 327
Kobiella, A., 417
Kochanska, G., 27, 389, 391–393,
400, 408–410, 437, 438, 479,
566–568, 583, 584
Kochel, K. P., 397
Kochenderfer, B. J., 518, 543
Kam, C.-M., 534, 545, 546
Kaminski, J., 219
Kane, J. B., 493
Kanner, A. D., 526
Kao, G., 524
Kaplan, H., 191
Karevold, E., 396
Karmel, B. Z., 63
Karmiloff-Smith, A., 95, 153
Kärnä, A., 542, 589
Karrass, J., 390
Karriker-Jaffe, K. J., 578
Kärtner, J., 573
Kaskie, B., 311
Katz, L. F., 413, 414, 480, 546,
548
Katz, P. A., 610, 612
Katz, S. J., 542
Kaufman, A. S., 302
Kaukiainen, A., 628
Kavanaugh, R. D., 272
Kavoura, A., 529
Kawabata, Y., 518, 524, 539, 542
Kaye, K. L., 187
Kayed, N. S., 181
Keane, S. P., 406
Kearins, J. M., 286
Kearney, J. K., 155
Kearsley, R. B., 389, 391
Keating, D. P., 314, 357
Keefe, D. H., 182
Keen, R., 194, 211, 285
Keenan, K., 579, 580, 586
Keiding, N., 618
Keil, F. C., 262, 275, 276
Keiley, M. K., 396, 585
Keith, B., 489, 492, 495
Kelemen, D., 274
Keller, H., 573
Keller, M., 515
Keller, P. S., 585
Kellet, J., 492
Kelley, M. L., 475
Kelley, W. M., 314
Kellman, P. J., 173, 175, 179
Kellogg, R. T., 330
Kelly, D. J., 177
Kennedy, D., 122
Kennedy, R. E., 396
Kennedy, S., 486
Kenny, D. A., 477
Kenny, P. A., 365
Kenrick, D. T., 596
Kenyon, D. B., 490
Kermoian, R., 162, 284, 400,
470
Kerns, K. A., 437, 545
Kerr, M., 474, 475, 477
Kessen, W., 9, 175
Kestenbaum, R., 438, 545

NI-10 n N A M E I N D E X
Madden, M., 373
Madole, K. L., 264
Madon, S., 623
Maes, H. H., 580
Maffei, L., 116
Magalhaes, L., 489
Magnuson, K., 490
Magnusson, S. J., 327
Maguire, M. C., 519
Main, M., 347, 372
Mainela-Arnold, E., 251
Maiti, A. K., 406
Makel, M. C., 314
Malatesta, C., 388
Malcolm, K. T., 518
Maliken, A. C., 414, 548
Malina, R. M., 617
Malone, P. S., 489
Maloney, E. A., 334
Maltz, D. N., 611
Maluccio, J. A., 125
Mampe, B., 73
Mandara, J., 452
Mandell, D. J., 271
Mandich, A., 489
Mandler, J. M., 264
Mangelsdorf, S. C., 399, 438, 494
Manis, F. R., 326
Mannering, A. M., 273
Marceau, K., 478
Marchman, V. A., 232, 235, 251
Marcia, J. E., 447, 448
Marcoen, A., 460
Marcovitch, H., 95
Marcus, D. E., 600
Marcus, G. F., 243, 244
Marentette, P. F., 230
Margett, T. E., 278
Margolin, G., 480, 485
Markiewicz, D., 545
Markman, E. M., 237
Markow, D. B., 239
Marks, A. K., 452
Marks, K. S., 290
Markson, L., 251
Markstrom-Adams, C., 450–452
Markus, H. R., 415
Marler, P., 219
Marlier, L., 55, 186
Marsh, H. W., 442
Marshal, M. P., 457
Marshall, K. C., 518
Marshall, P. J., 204
Marshall, T. R., 406
Marsiglio, W., 487
Martin, C., 396, 479
Martin, C. L., 421, 524, 594–595,
600, 602, 603, 608, 609, 613,
625
Martin, J., 630
Losoff, M., 526
Lotze, G. M., 581
Loukas, A., 528
Lourenco, S. F., 292–293
Love, J. M., 320, 503
Lovejoy, M. C., 395
Lovett, M. W., 326
Low, S., 522
Low, S. M., 480, 483
Lozoff, B., 65
Lu, M. W., 483
Lubach, G. R., 59
Lubinski, D., 299, 306
Luby, J., 395, 397
Lucas, S., 457
Lucas-Thompson, R., 437
Luciana, M., 403
Luebbe, A. M., 413
Luengo Kanacri, B. P., 571
Luijk, M. P. C., 438
Luna, B., 151
Lunkenheimer, E. S., 413
Luntz, B. K., 584
Lupyan, G., 261, 264
Luria, Z., 611
Luster, T., 368, 479, 486
Lutchmaya, S., 363
Luthar, S. S., 19, 20, 377, 378
Lütkenhaus, P., 441
Lutz, D., 293
Luxen, M. F., 597
Luyckx, K., 448, 449
Lykken, D. T., 103, 493
Lynam, D. R., 582
Lynch, M., 370
Lynch, M. E., 612
Lynn, R., 313
Lyon, G. R., 326
Lyon, T. D., 288
Lyons, I. M., 335
Lyubomirsky, S., 397
Ma, W., 224
Mabbott, D. J., 331
Macari, S., 98
Macartney, S. E., 19
MacBrayer, E. K., 582
Macchi Cassia, V., 176
Maccoby, E. E., 473, 490, 493,
524, 603, 609–611, 613, 629
MacDonald, G. W., 323
MacDonald, K., 572
MacDonald, T. M., 572
MacEvoy, J. P., 520
MacFarlane, A., 186
MacKenzie, H., 241
MacLean, M., 324, 421
Macmillan, R., 586
MacPhee, D., 480
Macrae, M., 622
Li, D., 460
Li, J., 392
Li, Y., 474, 491, 585
Liaw, F. R., 77
Liben, L. S., 254, 601, 602, 608,
610
Libertus, K., 193, 287, 293
Lichter, D. T., 499
Lickliter, R., 103, 365, 596
Lickona, T., 557
Liew, J., 572
Lillard, A. S., 268, 272
Limber, J., 242
Limber, S., 529
Linares, L. O., 586
Lindahl, K. M., 494
Lindberg, S. M., 616
Lindell, S. G., 68
Linden, E., 219
Lindenberg, S., 534
Lindquist, K. A., 385
Lingeman, J. M., 191
Linkletter, A., 139
Linn, M. C., 616, 620, 624
Lins-Dyer, M. T., 565, 566
Lintern, V., 603
Lipman, E. L., 486
Lipsitt, L. P., 61
Lipton, J. S., 289
Litovsky, R. Y., 251
Little, J. F., 62
Little, S. A., 535
Little, T. D., 631
Litwack, S. D., 534
Liu, H.-M., 226, 227
Liu, L. L., 254
Liu, S., 177
Llewellyn, D. J., 123
Lloyd, B. B., 597
Lo Coco, A., 540
Lobo, M. A., 166
Locke, J., 8, 36, 348
Lockman, J. J., 186, 191, 193
Loeber, R., 578, 580
Loeches, A., 416
Loehlin, J. C., 103, 312
Loewy, J., 79
Lollis, S. P., 514
Loman, M. M., 184
Lombardi, C. M., 498
Lonardo, R. A., 531
London, K., 609, 616, 632
Long, J. D., 531
Longo, M. R., 292–293
Lonigan, C. J., 327
Loomis, J. M., 286
Lord, H., 504
Lorenz, K. Z., 363, 380
Los Angeles Police Department,
587
Le Grand, R., 285
Leadbeater, B., 396
Leadbeater, B. J., 543
Leaper, C., 594, 602–605, 607,
609–614, 618, 622, 624,
626–628, 631
Lease, A. M., 526
Lecanuet, J.-P., 53, 54
Lee, C.-Y. S., 470, 480
Lee, E. H., 409
Lee, H., 80
Lee, J., 458, 470
Lee, K., 17, 32, 153, 421, 458
Lee, L., 524
Lee, L. C., 573
Lee, S. S., 580
Lee, S-Y., 368
Lee, V. E., 624
Lee, Y., 487
LeFevre, J.-A., 331
Leggett, E. L., 21, 359
Leichtman, M. D., 160
Leidy, M. S., 470
Leinbach, M. D., 600, 613
Lemaire, P., 331
Lemerise, E. A., 629
Lemery, K. S., 103, 408, 626
Lengua, L. J., 409, 478, 548
Lenhart, A., 529, 530
Lenroot, R. K., 112
Leonard, L. B., 251
Lerner, R., 103
Leslie, A. M., 149, 206, 260, 266,
279
Lester, B. M., 63, 78
Leung, M-C., 526
Levant, R. F., 611, 624, 629
Leve, L. D., 613, 630
Levey, G., 101
Levin, I., 143, 288, 323, 328
Levin, J. R., 246
Levine, J. A., 307
Levine, J. S., 89, 101, 103
LeVine, R. A., 470, 483, 523
Levine, S., 313
Levine, S. C., 118, 283, 284, 289,
290
Lew, A. R., 284, 285
Lewinsohn, P. M., 397
Lewis, E. E., 403
Lewis, J. M., 496
Lewis, M., 73, 78, 202, 387–393,
417, 438, 440, 441, 573
Lewis, M. D., 406
Lewis, T. L., 115
Lewis, W., 244
Lewkowicz, D. J., 63, 188, 287
Lewontin, R., 96, 103
Lew-Williams, C., 232
Li, B., 539

N A M E I N D E X n NI-11
Mintz, T. H., 228
Mirescu, C., 109
Mischel, W., 149, 384
Mistry, J., 483
Mitchell, C., 582
Mitchell, K. J., 631
Mitchell, Z. A., 333, 334
Mix, K. S., 289, 290
Miyake, A., 149
Miyamoto, R. T., 251
Mize, J., 538
Mo, L., 158
Modecki, K. L., 458
Modin, B., 541
Mody, M., 326
Moen, P., 499
Moffitt, T. E., 149, 408, 409, 578,
579, 581, 583
Moilanen, K. L., 400
Molfese, D. L., 220
Moller, L. C., 613
Molnar, M., 222
Monahan, K. C., 521, 581
Mondloch, C. J., 113, 115
Monsour, A., 444
Montagner, H., 73
Montemayor, R., 624
Montgomery, R., 519
Montirosso, R., 417
Moon, C. M., 54, 55
Moon, M., 482
Moore, B., 560
Moore, C., 159
Moore, C. F., 20, 63
Moore, D. R., 487
Moore, K. A., 486
Moore, K. L., 42, 58
Moore, M. J., 175
Moore, M. K., 203
Moore, M. R., 486
Morales, J. R., 19, 20
Moreau, D., 621
Morelen, D., 478
Morelli, G. A., 18, 19
Morelli, M., 481
Morgan, E. M., 454
Morgan, J., 483
Morgan, J. L., 224
Morgan, M. C., 486
Morgan, R., 440
Morganstein, T., 526
Morikawa, H., 233, 234
Morison, V., 179, 183
Morris, A. S., 409, 412, 471, 582
Morris, J. K., 94
Morris, P. A., 366, 606
Morrissey, T. W., 503
Morton, J., 12
Moses, L. J., 417
Mosher, M., 535, 578
Mendelson, M. J., 524
Mendes Soares, L. M., 89
Mendle, J., 396
Mennella, J. A., 53, 55, 122
Menon, M., 459
Menon, V., 334
Merkin, S., 291
Mermelstein, R., 396
Merrell, K. W., 616
Merten, D. E., 535
Mervis, C. B., 95, 152
Mesman, J., 409, 578
Mesquita, B., 386, 415
Messner, M. A., 631
Mestre, M. V., 563
Mettetal, G., 516
Metz, E., 575
Metzger, A., 565
Meunier, J. C., 484
Meyers, T., 202
Michalik, N. M., 575
Michalson, L., 417
Michigan State Legislature, 5
Mickelson, K. D., 482
Miell, D., 519
Mikami, A. Y., 529
Miklikowska, M., 575
Milberger, S., 370
Miles, C. J., 494
Milewski, A. E., 175
Miliotis, D., 481
Mill, J., 12
Mill, J. S., 87–88
Miller, 142
Miller, B. C., 486
Miller, C. L., 486
Miller, D. C., 625
Miller, D. J., 112
Miller, D. P., 499
Miller, G. A., 246
Miller, G. E., 20, 99
Miller, J., 574
Miller, J. E., 314
Miller, J. G., 564, 565
Miller, J. M., 528, 587
Miller, K., 140
Miller, K. F., 253, 289, 291, 292
Miller, P., 416
Miller, P. H., 33, 142, 151, 153,
167, 350
Miller, P. J., 245
Miller, P. M., 626, 629, 630
Miller, S., 531
Miller, S. A., 267, 271
Miller-Johnson, S., 487
Minde, K., 80
Mineka, S., 348
Miner, J. L., 578
Miniño, A. M., 74
Minton, J. L., 201
McCrory, E. J., 579
McDaniel, M. A., 246, 299
McDonald, K. L., 519
McDonnell, H., 424
McDonough, C., 233
McDonough, L., 264
McDougall, P., 515, 519
McDowell, D. J., 545–548
McElwain, N. L., 411, 413, 437,
518, 545
McEwen, B. S., 108
McFadyen-Ketchum, S. A., 585
McFarland, F. C., 522, 586
McGill, B., 485
McGill, R. W., 524
McGowan, P. O., 12
McGraw, M. B., 191
McGue, M., 21, 102, 103, 309,
493, 583
McGuigan, F., 160
McGuire, S., 460, 485
McHale, J. L., 438, 494
McHale, J. P., 186, 480
McHale, S. M., 470, 471, 483–
485, 625
McKelvey, M. W., 476
McKenry, P. C., 476
McKey, R. H., 317, 319
McKinley, N. M., 619
McLeod, P. J., 223
McLoyd, V. C., 19, 317, 319, 460,
462, 475, 480, 548
McMahon, A. W., 95
McMahon, R. J., 581, 588
McMahon, S. D., 576
McManus, T., 490
McMaster, L. E., 612, 631
McMillan, D., 601
McMurray, B., 236
McNeil, N. M., 333
McQuaid, N., 411
McShane, K. E., 571
Meaney, M. J., 11, 12, 98
Mebert, C. J., 584
Meck, E., 291
Medin, D. L., 262
Meece, J. L., 334
Meert, G., 332
Meeus, W., 448, 452, 518
Meeus, W. H. J., 518
Meeus, W. J., 522
Mehler, J., 55, 222
Meier, M. H., 580
Meisels, S. J., 77, 78, 80, 324, 536
Meister, C., 327
Melander, L. A., 481
Meltzoff, A. N., 159, 187, 203,
204, 208, 240
Menaghan, E. G., 499
Mendel, G., 88
Martin, J. A., 64, 68, 76, 473, 486,
488
Martin, M. J., 395, 480, 482
Martin, T. C., 489
Martinez, M. E., 75
Martini, T. S., 412, 413, 415
Martinot, D., 624
Martin-Storey, A., 457
Martorell, G. A., 403
Marzolf, D. P., 254, 399
Masalha, S., 480, 546
Masataka, N., 184, 223
Mascolo, M. F., 392, 393
Mashek, D. J., 393
Mason, C. A., 448
Mason, M. G., 560
Masten, A. S., 20, 80, 481
Masur, E. F., 236
Maszk, P., 535
Matheson, C. C., 13, 514
Matsuba, M. K., 561
Matsumoto, D., 415
Matthews, G., 385
Mattock, A., 178
Mattson, S. N., 62
Maurer, C., 53, 67, 199
Maurer, D., 53, 67, 113, 115, 175,
199
Maya-Ventencourt, J. F., 92
Mayberry, M. L., 629
Mayer, B., 572
Mayeux, L., 535
Maynard, J., 183
Mayringer, H., 326
Mayseless, O., 545
Mazzocco, M. M. M., 335
McAdams, D. P., 309
McAdoo, H., 368
McArdle, J. J., 300, 302
McBride-Chang, C., 324
McCabe, A., 245
McCabe, K. M., 581
McCabe, P. C., 538
McCaffrey, D. F., 664
McCall, R. B., 6
McCarthy, A., 421
McCartney, K., 21, 97, 102, 503
McCarton, C. M., 80
McCarty, M. E., 194
McCaskill, P. A., 481
McClain, D. B., 491
McClelland, J. L., 252, 279
McClelland, M. M., 149
McClintock, M. K., 619
McCloskey, L. A., 372
McCloskey, M., 335
McConnell, D., 470, 480
McCormick, M. C., 79
McCoy, D. C., 412
McCrae, M., 622

NI-12 n N A M E I N D E X
Orue, I., 582
Osborne, L. R., 95
Osofsky, J. D., 633
Östberg, V., 541
Oster, H., 122, 389
Österman, K., 628
Osterman, M. J. K., 76
Ostrov, J. M., 578
Otake, M., 118
Oveis, C., 406
Overbeek, G., 532
Overman, W., 286
Overton, W. F., 600
Owsley, C., 200
Oxford, M. L., 536, 537
Ozcaliskan, S., 248
Özdemir, M., 474
Ozonoff, S., 270
Padilla, Y. C., 480
Padilla-Walker, L. M., 483, 575
Page, T. F., 493
Pahl, K., 451
Paik, H., 632
Pakulak, E., 221
Paley, V. G., 282
Palincsar, A. S., 327
Palmen, H., 518
Palmer, S. B., 227
Panagiotaki, G., 557
Panfile, T. M., 437, 438, 545
Papini, D. R., 471
Paquette, J. A., 518
Paradis, J., 222
Parcel, T. L., 499
Pardini, D. A., 581
Parents Television Council, 374
Park, G., 306
Parke, R. D., 451, 462, 470, 472,
474, 475, 480, 482, 483, 489,
491, 492, 495, 539, 545–548,
577
Parker, J. G., 372, 401, 511, 517,
520, 541, 543
Parritz, R. H., 399
Pascalis, O., 176
Paschall, M. J., 461
Pascual-Leone, A., 117
Pattee, L., 534
Patterson, C. J., 372, 496, 497,
540, 548, 610, 612
Patterson, F., 219
Patterson, G. R., 26, 478, 483,
585, 624
Patteson, D. M., 78
Pattison, P. E., 333
Pauker, K., 177
Paulhus, D. L., 464
Paulson, S. E., 498
Paus, T., 151
Nisbett, R. E., 121, 309, 313–315
Nishina, A., 452, 543
Noack, P., 524
Nobes, G., 557
Noël, M.-P., 332
Nolen-Hoeksema, S., 395–397
Nordenström, A., 599
Nordhal, C. W., 270
Nordhov, S. M., 78
Nosek, B. A., 348
Nowell, A., 620, 621
Nucci, L. P., 560, 564–566
Nugent, J. K., 78
Nurmi, J.-E., 448
Nylund, K., 543
Oakes, L. M., 264, 279
Oakhill, J., 325
Obama, M., 124
Oberlander, T. F., 12
Oberman, Y., 501
Obradovic, J., 406, 481, 543
O’Brien, M., 500
Ocampo, K. A., 451
Ochs, E., 224
O’Connor, A., 495, 496
O’Connor, T. G., 7, 66, 97, 493
Oden, S., 538
Odgers, C. L., 586
O’Doherty, K., 241
O’Donnell, C. E., 587
O’Donnell, D. A., 395
Offord, D. R., 580
Ogbu, J. U., 606
Ogden, C. L., 122
Oh, W., 536
Öhman, A., 348
O’Leary, K. D., 631
Oliner, P. M., 574
Oliner, S. P., 574
Oliver, B., 326
Ollendick, T. H., 541
Oller, D. K., 222, 230
Olson, B. D., 309
Olson, L. S., 313
Olson, R. K., 326
Olson, S. L., 311, 401, 581, 583
Olweus, D., 543
O’Neil, R., 368
Onishi, K. H., 211
Opfer, J. E., 134, 275, 332
Oppliger, P. A., 605
O’Reilly, A. W., 271
Orgeur, P., 53
Origlia, N., 92
Oriña, M. M., 532
Ornstein, P. A., 160
O’Rourke, J. A., 95
Orth, U., 458
Ortmann, M. R., 479
National Poverty Center, 480
National Reading Panel, 323
National Science Foundation,
621, 624
National Survey on Drug Use
and Health, 63
Natsuaki, M. N., 483, 489
Neal, J. W., 526
Neblett, E. W., 452, 453
Neckerman, H. J., 526
Nederhof, E., 589
Needham, A., 164, 180, 193,
206–208
Negriff, S., 396
Neiderhiser, J. M., 472
Neisser, U., 347
Nelson, 283
Nelson, C. A., 6, 7, 148, 176, 476
Nelson, D. A., 540, 582
Nelson, E. A., 18
Nelson, H. D., 251
Nelson, J., 519
Nelson, J. K., 283
Nelson, K., 160, 233, 245, 273
Nelson, L. J., 575
Nesdale, D., 602
Neumark-Sztainer, D., 124
Neville, B., 489
Neville, H. J., 115, 221
Newcomb, A. F., 521, 533–535,
539
Newcombe, N., 283, 286
Newell, K. M., 193
Newland, M. C., 57
Newman, J., 121
Newman, M., 101
Newman, R. S., 154, 229
Newman, S. D., 649
Newport, E., 223
Newport, E. L., 173, 200, 221,
228, 248, 251
Newsome, M., 228
Newton, I., 157
Nguyen, S. P., 277, 604
Nguyen, T., 275
NICHD Early Child Care
Research Network, 438, 489,
502–504, 578, 581, 585
Nichols, S., 271, 570
Nicholson, T., 327
Nickerson, P., 524
Nicoladis, E., 222
Nicolopoulou, A., 272
Nicotra, E., 526
Nieder, A., 289
Nielsen, M., 440
The Nielsen Company, 605
Nilsen, E. S., 246
Ninomiya, K., 562
Nisan, M., 561
Mosher, W. D., 487–489
Mosier, C., 483
Moss, E., 438
Mounts, N. S., 523, 547
Mouse Genome Sequencing
Consortium, 89
Mozart, W. A., 321
Mrug, S., 521
Mu, Y., 292
Mueller, S. C., 621
Muir, D., 54
Muir, D. W., 73, 388
Muller, C., 499
Mulligan, K., 385
Mullin, J. T., 176
Mulvaney, M. K., 584
Mumme, D. L., 417
Munakata, Y., 131, 149, 206
Mundy, L., 577
Munekata, H., 562
Munroe, R. H., 600
Munroe, R. L., 600
Muraskas, J., 76, 77
Murnen, S. K., 605
Murphy, B. C., 394, 408, 417, 572
Murphy, G. L., 262
Murphy, R. R., 394
Murphy, S. L., 74
Murray, E., 613
Murray, K. T., 27, 400
Musolino, J., 94
Mussen, P., 557
Mussen, P. H., 573
Mustonen, U., 489
Muzio, J. N., 71
Myers, L. J., 254
Myhill, D., 623
Mylander, C., 248
Myowa-Yamakoshi, M., 53
Naab, P., 418
Nadig, A. S., 246
Nagel, L., 389
Nagel, S. K., 368
Nagell, K., 159
Naigles, L. G., 235, 240
Najarian, P., 317
Nakamoto, J., 543
Nakata, T., 184
Namy, L. L., 241
Náñez, J. E., Sr., 181
Nantel-Vivier, A., 571
Narusyte, J., 472
Nathanielsz, P. W., 48, 52, 67
Nation, K., 323, 325
National Association for the
Education of Young Children,
161, 505
National Law Center on
Homelessness and Poverty, 481

N A M E I N D E X n NI-13
Rayner, K., 323
Rayner, R., 349
Raynor, S. R., 484
Raz, N., 599
Razza, R. P., 17, 149, 335
Ream, G. L., 454, 456, 457
Reardon, P., 200
Rebello Britto, P., 184
Reed, C., 205
Reed, J. M., 147
Reese, E., 160, 245, 414
Reeve, R. A., 333
Regan, L., 56
Regan, P. C., 531
Regolin, L., 178
Reich, S. M., 529
Reid, J. B., 483, 585
Reid, M. J., 538
Reijntjes, A., 530, 536, 542
Reis, H. T., 531
Reiser, M., 541
Reiss, D., 412
Reissland, N., 419
Relier, J. P., 66
Ren, A., 63
Rende, R., 583
Renken, B., 545
Renold, E., 624
Repetti, R. L., 520
Rescorla, L. A., 234
Rest, J., 560, 561
Restifo, L. L., 309
Reynolds, A. J., 317
Reznick, J. S., 165
Rhee, S. H., 370, 583
Rheingold, H. L., 391, 440, 570,
609
Rhoades, K., 479
Rhoades, K. A., 412
Ricard, M., 274
Rice, M. L., 251, 372
Richards, M., 499
Richards, M. H., 471, 527, 531
Richards, T. L., 328, 329
Richman, C. L., 574
Richman, W. A., 287
Richmond, M. K., 532
Rideout, V. J., 373–375
Ridley, K. S., 334
Ridley-Johnson, R., 192
Rieser, J. J., 284
Rieser-Danner, L. A., 177
Riggs, N. R., 538
Riina, E. M., 470
Rimm-Kaufman, S. E., 401
Rinaldi, C. M., 474
Rinelli, R. N., 490
Risley, T. R., 235, 479
Riva Crugnola, C., 437
Rivas-Drake, D., 451, 452
Prinstein, M. J., 521, 527, 531,
535, 541
Proffitt, D. R., 178
Pruett, M. K., 490
Puhl, R. M., 122
Pulkkinen, L., 581
Punamäki, R.-L., 529
Putallaz, M., 314, 474, 534
Putnam, S. P., 73, 399, 400
Putnick, D. L., 483
Puzzanchera, C., 577, 579
Pyke, A. A., 333
Pythagoras, 184
Qin, D. B., 451
Quarles, J., 52
Quay, S., 222
Quiggle, N. L., 582
Quine, W. V. O., 231, 237, 239
Quinn, G. E., 29
Quinn, M., 514
Quinn, P. C., 176, 177, 263, 283
Quinn, P. D., 307
Quinsey, V. L., 583
Quintana, S. M., 451
Raberger, T., 326
Raboy, B., 497
Radke-Yarrow, M., 391, 570
Raevuori, A., 460
Rafferty, Y., 481
Raghubar, K. P., 335
Ragozin, A. S., 488
Rai, R., 56
Raikes, H., 320, 327
Raikes, H. A., 398, 411, 545
Rakic, P., 109
Rakison, D. H., 10, 261, 264
Ramadoss, J., 60
Ramani, G. B., 154, 196, 333, 514
Ramey, C. T., 79, 318–319
Ramey, S. L., 318–319
Ramirez, G., 334
Ramsey, N. F., 583
Randles, D., 385
Raninen, A., 285
Ransom, C. C., 327
Rao, N., 573
Rapee, R. M., 397
Rasbash, J., 402, 403, 472, 478
Rasmussen, E. B., 57
Rasmussen, P., 582
Rasmussen, S., 282
Rasmussen, S. A., 60
Ratliff, K. R., 283
Ratner, N., 230
Rattan, A., 361
Rauer, A. J., 532
Raval, V. V., 412, 413, 415
Raver, C. C., 149, 412
Pilkington, N. W., 457
Pillard, R. C., 453
Pillow, B. H., 268
Pinderhughes, E. E., 479
Pine, D. S., 409
Pine, J. M., 233
Pinker, S., 243, 250
Pinto, J. P., 232
Pipe, M. E., 5
Pisoni, D. B., 226
Pizzini, E. L., 623
Plato, 8, 36
Plomin, R., 11, 97, 102, 103, 105,
123, 309, 312, 326, 328, 572,
575, 583
Plude, D. J., 406
Pluess, M., 409, 410, 478, 503
Plumert, J. M., 153, 155
Plunkett, J. W., 77, 78, 80
Plunkett, S. W., 575
Polit, D. F., 468
Polka, L., 222, 227
Polkosky, M., 243
Pollack, H. A., 124
Pollak, S. D., 358, 372, 410
Pollitt, E., 64, 125
Pomerantz, E. M., 524
Pomerleau, A., 609
Ponitz, C. C., 401
Pons, F., 187, 222, 419
Poole, D. A., 5
Popaleni, K., 631
Popkin, B. M., 121
Popp, D., 522
Porche, M. V., 235
Porges, S. W., 406
Porter, M. R., 522, 586
Porter, R. H., 55, 186
Poskiparta, E., 589
Posner, M. I., 16, 73, 410
Poston, D. L., Jr., 468
Potter, D., 489
Poulin, F., 520, 522–524, 526,
612
Poulin-DuBois, D., 237, 239,
264, 274, 608
Powell, D., 368
Powell, G. F., 120
Powell, L. J., 269
Power, C., 489
Power, T. G., 413
Powlishta, K. K., 602, 603, 608,
610, 613
Pratt, M. W., 160, 575
Prechtl, H. F. R., 51
Presley, E., 91
Pressley, M., 151, 246, 324, 327
Preves, S. E., 599
Price, T. S., 103
Principe, G. F., 4
Pawson, C., 557
Peake, P. K., 384
Pears, K. C., 630
Pearson, B. Z., 222
Pedersen, P. E., 46
Pedersen, S., 518, 521, 524, 535,
612
Pegg, J. E., 223
Peisner-Feinberg, E. S., 503, 504
Peláez-Nogueras, M., 73
Pellegrini, A. D., 364, 531, 594,
596, 610
Pellegrino, J. W., 161
Pellizzoni, S., 558
Pelucchi, B., 229
Pena, M., 220
Penhune, V. B., 220
Pepperberg, I. M., 219
Perani, D., 110
Perfors, A., 232
Perlman, S. B., 358
Perlmutter, M., 244
Perner, J., 557
Perris, E. E., 206
Perry, D. G., 574, 582, 630
Perry, L. C., 582, 630
Persaud, T. V. N., 42, 58
Peter, J., 529, 530
Peterman, K., 164, 193
Petersen, A. C., 396, 526, 612,
614, 620
Peterson, C., 245
Petitto, L. A., 230
Petrill, S. A., 312, 328, 410
Pettersen, L., 182
Pettit, G. S., 548, 586
Philibert, R. A., 410, 437
Philippot, P., 418
Philips, K. J., 525
Phillips, A. T., 267, 268
Phillipsen, L., 514
Phillips-Silver, J., 188
Phinney, J. S., 450, 451
Phipps, M. G., 64
Piaget, J., 15, 130–146, 152,
155–157, 163–165, 167–169,
186, 206, 212, 244, 284, 288,
292, 293, 342, 357, 512, 513,
516, 517, 519, 525, 549, 550,
555–558, 566, 570, 590, 600,
648, 662
Piasta, S. B., 323
Picasso, P., 84
Pick, A. D., 164, 187
Piehler, T. F., 521
Pierce, T., 529
Pierroutsakos, S. L., 183
Pike, A., 484
Pike, R., 442
Pilgrim, C., 521, 523

NI-14 n N A M E I N D E X
Scherer, K. R., 385
Schermerhorn, A. C., 494
Schiefenhoevel, W., 18
Schieffelin, B. B., 224
Schlaggar, B. L., 326
Schlomer, G. L., 395
Schmaling, K. B., 578
Schmeck, H. M., 108
Schmidt, F. L., 307
Schmidt, J., 288
Schmidt, M. E., 31, 518
Schmit, S., 318
Schmitt, M. J., 335
Schmuckler, M. A., 195
Schneider, B., 378
Schneider, B. H., 535, 539, 545
Schneider, M., 333
Schneider, W., 147, 149, 152, 153
Schniering, C. A., 397
Schoeber-Peterson, D., 244
Schoefs, V., 460
Schoenfeld, T. J., 109
Schofield, T. J., 480
Scholl, B. J., 206, 260
Scholte, R. H. J., 521
Schöner, G., 165
Schoppe-Sullivan, S. J., 471
Schouten, A. P., 529
Schuetze, P., 60
Schulenberg, J., 521
Schull, W. J., 118
Schult, C. A., 275
Schultz, D., 418
Schulz, L., 205
Schulz, L. E., 281
Schumann, C. M., 270
Schuster, M. A., 457
Schutte, A. R., 165
Schwade, J., 250
Schwartz, D., 518, 539, 540, 542,
543
Schwartz, M. B., 122
Schwartz, O. S., 396
Schwartz, P. D., 444
Schwartz, S., 26
Schwartz, S. J., 448
Schwartz-Mette, R. A., 396, 520
Schwarz, B., 523
Scott, P. M., 574
Scott, R. M., 265
Seaton, E., 480
Seaton, E. K., 451, 462
Sebanc, A. M., 514
Sebastián-Gallés, N., 222
Sebby, R. A., 471
Sedivy, J. C., 246
Seehagen, S., 514
Segal, N. L., 312
Seidman, E., 461
Seier, W. L., 167
Sagi, A., 501
Sai, F., 176
Sakai, T., 112
Salapatek, P., 175, 390, 391
Sale, A., 116
Salihovic, S., 584
Sallquist, J. V., 389, 394, 408, 542
Salmivalli, C., 526, 542, 589
Salmon, K., 160
Salovey, P., 400
Salthouse, T. A., 300
Salvas, M.-C., 520
Salvatore, J. E., 532
Salzinger, S., 372
Samaniego, R., 275
Sameroff, A. J., 80, 305, 316
Sampa, A., 481
Sampson, M., 480
Sampson, R. J., 584
Samuelson, L. K., 164, 236, 239,
252
Samuelsson, S., 23
Sanborn, M. E., 442
Sanchez-Hucles, J., 475
Sanders, P., 622, 628
Sanders-Jackson, A., 529
Sandler, W., 249
Santo, J. B., 518
Sapiro, C. M., 564
Saraswati, T. S., 522
Sarigiani, P. A., 396, 614
Satlow, E., 283
Saudino, K. J., 51, 103, 402, 403,
410, 477, 478
Savage, A., 470
Savage-Rumbaugh, E. S., 219
Savelsbergh, G. J., 166
Savin-Williams, R. C., 453–458,
531
Sawaya, A. L., 23
Saxe, G. B., 160
Saxe, R., 269
Sayer, L. C., 613
Sayfan, L., 419
Scanlon, D. M., 323, 326
Scaramella, L. V., 479, 480, 486,
488, 583
Scardamalia, M., 330
Scarpa, A., 581
Scarr, S., 20, 21, 97, 102, 309,
390, 391, 503
Schaal, B., 53, 55, 186
Schaefer, D. R., 524
Schaeffer, C. M., 579
Schafer, W. D., 625
Schaps, E., 576
Scharff, C., 94
Scheitenberger, S., 411
Schellenberg, E. G., 184
Schenck, C., 495
Rosenshine, B., 327
Rosenstein, D., 122
Rosenthal, S., 438
Ross, D., 352
Ross, D. F., 630
Ross, G., 159
Ross, H., 630
Ross, H. S., 514, 578
Ross, N., 275
Ross, S. A., 352
Rotenberg, K. J., 420
Rothbart, M. K., 11, 16, 17, 73,
389, 400, 403–410, 581
Rotheram, M. J., 450
Rotheram-Borus, M. J., 454, 456
Roth-Hanania, R., 570
Rothstein-Fisch, C., 18
Rousseau, J-J., 8, 36
Rovee-Collier, C., 202
Rowe, D. C., 105, 312
Rowe, M. L., 248
Rowley, S. J., 603
Roy, R., 526
Rubenstein, A. J., 177
Rubin, K., 415
Rubin, K. H., 272, 401, 458, 511,
515, 519, 524–527, 534–537,
539–542, 546
Ruble, D. N., 421, 442, 595
Rudolph, K. D., 395, 397, 401,
519, 520, 524, 543, 611, 616,
626, 629, 630
Rueda, M. R., 17
Rueter, M. A., 478
Ruff, H. A., 186, 399
Ruffman, T., 266, 271, 413
Rumelhart, D. E., 252
Ruskin, E., 270
Russell, A., 482, 483, 548
Russell, G., 482, 483
Russell, J. A., 417, 418
Russell, S. T., 474, 497
Rutland, A., 524
Rutten, B. P., 12
Rutter, M., 6, 7, 80, 497
Ryan, C., 457
Rydell, A.-M., 411, 545
Rymer, R., 220
Saarni, C., 385, 386, 417, 420,
421
Sabbagh, M. A., 149, 238, 265
Sabongui, A. G., 533
Sackett, P. R., 307
Sadato, N., 116
Saewyc, E. M., 454, 457, 458
Saffran, J. R., 182, 184, 200, 224,
228, 229, 244, 251
Sagart, L., 230
Sager, D. W., 575
Rivera, S., 290
Rivera, S. M., 335
Rizzo, G., 52
Rizzolatti, G., 204
Roberts, B. W., 307, 408, 458
Roberts, D. F., 375
Roberts, R. D., 385
Roberts, T. A., 442
Robertson, D. L., 535, 536, 539
Robertson, J., 392
Robertson, R. R. W., 184
Robertson, S. S., 52
Robe-Torres, K., 251
Robin, D. J., 193
Robins, R. W., 458
Robinson, H., 306
Robinson, J., 392, 567
Robinson, M., 581
Robinson, N. M., 306
Robinson, S. R., 46, 195, 197
Robinson, T. N, 124
Robnett, R. D., 624, 631
Rochat, P., 186, 193, 290, 440
Roche, K. M., 479
Rocissano, L., 245
Rodgers, B., 489
Rodkin, P. C., 526, 534, 536
Rodriguez, M. L., 384
Roesch, L., 396
Roffwarg, H. P., 71
Rogers, F., 15
Rogers, T. T., 279
Roggman, L. A., 177
Rognon, C., 53
Rogoff, B., 156, 522
Rogosch, F. A., 372, 589
Rohde, P., 397
Roisman, G. I., 478, 581
Rollins, A., 524
Romanini, C., 52
Rommetveit, R., 159
Ronald, A., 95
Roopnarine, J. L., 483
Roosa, M. W., 476
Ropelato, J., 376
Rosch, E., 264
Rose, A., 624
Rose, A. J., 396, 519, 520, 524,
531, 535, 611, 614, 616, 626,
629, 630
Rose, D., 183
Rose, H., 613
Rose, S. A., 149, 199
Roseberry, S., 200, 251
Rosen, L. H., 533
Rosenberg, M., 444
Rosenberger, K., 368
Rosenfeld, A., 378
Rosengren, K. S., 197, 244, 253,
276, 281

N A M E I N D E X n NI-15
Spencer, A., 497
Spencer, J. P., 78, 162, 165, 193
Spencer, M. B., 450–452
Spencer, W. A., 54
Spencer-Rodgers, J., 464
Sperry, L. L., 245, 416
Spilich, G. J., 152
Spinath, B., 624
Spinazzola, J., 165
Spindler, A., 633
Spinrad, T., 74
Spinrad, T. L., 401, 408, 412, 438,
571, 572, 583
Spivak, A. L., 514
Sprague, J., 479
Sprenger-Charolles, L., 326
Springer, K., 275, 276
Squire, L. R., 147
SRCD Governing Council, 35
Srinivasan, M., 293
Sroufe, L. A., 386, 388, 390, 438,
544, 545, 603, 611
St. James-Roberts, I., 73, 74
Stack, D. M., 73, 206
Stams, G. J., 561
Stangor, C., 601, 610
Stanley-Hagan, M., 492, 493, 495
Stanovich, K. E., 325
Starkey, P., 290
Starzyk, K. B., 583
Stattin, H., 474
Staub, E., 574
Stecher, B. M., 664
Steeger, C. M., 474
Steele, H., 411, 438
Steele, M., 411, 438
Steenbeek, H., 166
Stein, N. L., 245
Steinberg, L., 368, 394, 400, 471,
475, 491, 521, 523, 525, 527,
531, 586
Steiner, J. E., 122
Steinmayr, R., 624
Stenberg, C. R., 73
Stern, D. N., 440
Sternberg, R. J., 301, 307, 320–
322, 336
Sterrett, E. M., 461
Stettler, N. M., 414, 548
Stevens, N., 517
Stevens, T., 606
Stevenson, H. W., 154, 368, 522,
573
Stewart, A. J., 495
Stewart, S. M., 573
Stifter, C. A., 73, 74, 399
Stiles, J., 109
Stipek, D. J., 25, 392, 442
Stocker, C. M., 412, 414, 532
Stoddard, A. K., 296
Smider, N. A., 407
Smiler, 454
Smiley, P. A., 359
Smith, A. M., 57, 63
Smith, B. A., 74
Smith, C., 528
Smith, C. L., 625
Smith, D. W., 62
Smith, E. D., 272
Smith, H. J., 410
Smith, J., 95
Smith, L., 162–163, 164, 239,
264
Smith, L. B., 13, 15, 164, 165,
239, 334
Smith, L. M., 63
Smith, M., 372
Smith, P. L., 625
Smith, R. L., 520
Smith, T. E., 594, 612, 622, 626,
628
Smith, W. E., 57
Smitsman, A. W., 289
Smollar, J., 471, 614
Smotherman, W. P., 46
Snarey, J. R., 561
Snidman, N., 406
Snow, C. E., 250, 441
Snyder, H. N., 587
Snyder, H. R., 149
Snyder, J., 413, 483, 521, 542, 585
Snyder, J. J., 578
Snyder, M., 575
Snyder, T. D., 619, 621
Sobel, D. M., 280
Soenens, B., 448, 474, 575
Soken, N. H., 187
Sokol, R. J., 62
Solmeyer, A. R., 484
Solomon, D., 576
Solomon, G. E. A., 276
Sommerville, J., 281
Sommerville, J. A., 208, 268
Song, C., 489
Sophie, J., 456
Sorenson, A., 460
Sosa, B., 153
Sosinsky, L. S., 504
Soska, K. C., 193
Soussignan, R., 55
Sowislo, J. F., 458
Spearing, D., 326
Spearman, C. E., 299
Spelke, E. S., 173, 179, 187, 200,
206, 207, 210, 260, 262, 267,
279, 283, 289, 292, 293
Speltz, M. L., 579
Spence, I., 621
Spence, M. J., 40, 55
Spence, S. H., 397
Shrum, W., 526
Shutter, J. M., 389
Shutts, K., 211
Shweder, R. A., 565
Sickmund, M., 587
Siebenbruner, J., 531, 532
Siegal, M., 558
Siegler, R. S., 10, 33, 34, 134, 143,
150, 152–154, 280, 281, 292,
324–326, 331–334
Sigman, M., 65, 270
Signorella, M. L., 601, 602, 616
Signorielli, N., 605
Sijtsema, J. J., 582
Silbert-Geiger, A., 373
Silk, J. S., 397
Silva, P. A., 408, 581
Silver, L. B., 370
Silver, R. C., 395
Silverberg, S. B., 586
Silverman, W. K., 394
Simcock, G., 98
Simion, F., 176, 178
Simon, T., 298, 336
Simon, T. J., 146, 290, 335
Simon, V. A., 531
Simons, R. L., 489, 491, 588, 589
Simpkins, S. D., 520, 532
Simpson, E. L., 561
Simpson, J. A., 545
Sims, M., 629
Singer, L. T., 63
Singh, L., 224
Singleton, J. L., 248
Sippola, L. K., 520
Sitarenios, G., 621
Sjaastad, J. E., 314
Skakkebaek, N. E., 618
Skinner, B. F., 247–248, 250,
350–351, 356, 380
Skinner, C., 80
Skinner, E. A., 399, 400, 460, 479
Skipper, J. I., 117
Skoe, E. E., 562
Skwerer, D. P., 94
Slaby, R. G., 577, 582, 600
Slade, L., 266, 271
Slater, A., 177–180, 183
Slaughter, V., 209, 268, 274, 440
Slemmer, J. A., 200, 251, 283
Slomkowski, C., 483
Slotkin, T. A., 67
Slough, N. M., 588
Sloutsky, V., 261
Slutske, W. S., 408
Sluzenski, J., 283
Smallwood, A. M. K., 529
Smeeding, T. M., 19
Smerdon, B. A., 624
Smetana, J. G., 475, 476, 564, 565
Seifer, R., 407
Seiffge-Krenke, I., 532
Selfe, L., 255, 256
Selfhout, M. H. W., 522, 529
Seligman, L., 636
Seligman, M. E. P., 397
Sellers, R. M., 462
Selman, R. L., 356–357, 380, 516
Senghas, A., 248, 265
Sentse, M., 471
Serbin, L. A., 608, 610, 613, 623,
629
Serrano, J. M., 416
Sesma, A., Jr., 481
Setiono, K., 539
Sevy, A. B. G., 111
Seward, R. R., 605
Seyfarth, R. M., 219
Shaffer, T. G., 594
Shafman, D., 238
Shaftesbury, Earl of, 9
Shalev, R. S., 335
Shanahan, L., 471, 484
Shannon, E., 175
Shantz, C. U., 578
Shapiro, D. N., 495
Shapiro, J. R., 399
Shapiro, L. R., 153, 245
Share, D. L., 324
Shatz, M., 223, 275
Shaw, C. M., 463
Shaw, D. S., 479, 484, 578
Shaywitz, B. A., 326, 599
Shaywitz, S. E., 326
Sheehan, M. J., 584
Sheese, B. E., 16, 17, 410
Sheffield, J. K., 397
Shell, R., 601
Shepard, S., 417
Shepardson, D. P., 623
Sheridan, C. J., 110
Shetty, P., 24
Shi, R., 232
Shields, A. M., 413
Shiller, V. M., 392
Shimmin, H. S., 600
Shin, M., 514
Shin, N., 452, 462
Shiner, R. L., 403
Shinn, M., 481
Shirley, L., 608
Shirtcliff, E. A., 407
Shoal, G. D., 407
Shoda, Y., 384
Shomaker, L. B., 545
Short, J. F., Jr., 587
Short, K. R., 179
Shortt, J. W., 483
Shrestha, S., 393
Shrout, P. E., 195

NI-16 n N A M E I N D E X
Trzesniewski, K. H., 22, 360, 442,
458
Tsang, C. D., 184
Tsao, F.-M., 226, 227
Tseng, V., 453
Tsukayama, E., 307
Ttofi, M. M., 589
Tucker-Drob, E. M., 312
Tully, L. A., 370
Turati, C., 176
Turiel, E., 561, 564, 565, 610
Turkewitz, G., 365
Turkheimer, E., 99, 103, 312, 523
Turley, R. N. L., 461
Turner, C. M., 395
Turner, J., 603
Turner, P. J., 613
Tuvblad, C., 583
Twenge, J. M., 395, 396, 462
Twyman, K., 529
Tyler, K. A., 481
Tynes, 452
Tyrka, A. R., 618
Udry, J. R., 453, 531
Uller, C., 291
Umaña-Taylor, A. J., 452, 462
Underwood, B., 560
Underwood, M. K., 533, 578, 630
Unger, O., 514
United Nations Children’s Fund,
76, 124, 315
United States Conference of
Mayors, 481
Updegraff, K., 485, 545, 547, 625
Urberg, K. A., 521, 522
Urbina, I., 481
U.S. Census Bureau, 19, 480, 489
U.S. Department of Health and
Human Services, 318, 319,
369, 498
U.S. Department of Health and
Human Services, Health
Resources and Services
Administration, Maternal and
Child Health Bureau, 500
U.S. Department of Labor, 498
Uttal, D. H., 196, 254
Vaccaro, B. G., 417
Vagi, K. J., 335
Vaillancourt, T., 578
Vaillant, G. E., 385
Vaillant-Molina, M., 417
Vainio, A., 565
Vaish, A., 417, 570
Valcárcel, J., 89
Valencia, R. R., 315
Valenza, E., 178, 200
Valenzuela, M., 480
Thomas, R. B., 73
Thompson, C. A., 333
Thompson, E. M., 439, 454
Thompson, H., 191
Thompson, L. A., 410
Thompson, R. A., 392, 406, 410,
411, 413, 438, 439, 441, 474,
545, 567
Thompson, R. F., 54, 106
Thompson, T., 605, 622
Thornberry, T. P., 584, 586
Thorne, B., 611
Thornhill, R., 313
Thurstone, L. L., 300
Tiedemann, J., 623
Tienari, P., 11
Tietjen, A. M., 522, 563
Tiggemann, M., 460
Tillman, K. H., 495
Tincoff, R., 231
Tinker, E., 250
Tipsord, J. M., 521
Tisak, M., 564
Tkachev, D., 108
Tokar, D. M., 624
Tokunaga, R. S., 529
Tolan, P. H., 586, 588
Tolchnisky, L., 328
Tom, S. R., 542
Tomada, G., 535, 539
Tomasello, M., 157, 159, 219,
236, 237, 250, 266, 512, 570,
575
Tomblin, J. B., 251
Tomkins, S. S., 386
Tomlinson, H. B., 272
Tooby, J., 10
Tooley, G. A., 365
Toomey, R. B., 457
Torassa, U., 29
Tornello, S. L., 497
Toro, P. A., 481
Toro, R. I., 470
Toth, S. L., 372, 395, 412
Tottenham, N., 7
Tout, K., 378
Towe-Goodman, N. R., 494
Tracy, J. L., 385
Trainor, L. J., 184, 185, 188
Trehub, S. E., 184, 185
Treiman, R., 324
Trentacosta, C. J., 586
Trinder, L., 492
Tripp, G., 414
Trivers, R. L., 365, 572
Trommsdorff, G., 572, 573
Tronick, E., 181
Tronick, E. Z., 73, 388, 399
Troop-Gordon, W., 518
Trost, M. R., 596
Suzuki, L. A., 315
Suzuki, L. K., 18, 463
Svetlova, M., 570
Swahn, M. H., 631
Swaim, R. C., 531
Sweet, J. A., 489
Swenson, L. P., 524, 535
Swift, L., 492
Swingler, M. M., 406
Swingley, D., 232
Szalacha, L. A., 451
Szatmari, P., 251
Szkrybalo, J., 595
Tach, L., 495
Tager-Flusberg, H., 94, 270
Taharally, L. C., 623
Tajfel, H., 603
Takeshita, H., 53
Tallal, P., 622
Tamang, B. L., 393, 396, 421
Tamis-LeMonda, C. S., 475, 476,
479
Tanaka, A., 326
Tandon, P. S., 123
Tangney, J. P., 393
Tanner, J. M., 16
Tardif, C., 545
Tardif, T., 233, 250, 479
Tarullo, A. R., 407
Task Force on Sudden Infant
Death Syndrome, 61
Tasker, F., 497
Taumoepeau, M., 413
Taylor, J., 583
Taylor, M., 273, 629
Taylor, M. G., 276, 604
Taylor, R., 480
Taylor, R. D., 480, 484
Taylor, T. J., 587
Tees, R. C., 226
Teglas, E., 205
Teicher, M. H., 46
Teinonen, T., 200
Tenenbaum, H. R., 594, 604, 622
Terrace, H. S., 219
Teti, D. M., 486
Teunissen, H. A., 396, 397
Thatcher, R. W., 151, 309
Thelen, E., 15, 162–163, 166,
191–193, 334
Thibodeau, E. L., 589
Thiessen, E. D., 224, 228
Thinus-Blanc, C., 285
Thomaes, S., 459, 530, 536
Thoman, E. B., 72, 73
Thomas, A., 403–404, 406, 409
Thomas, J. J., 608
Thomas, J. R., 616, 617
Thomas, K. M., 148, 476
Stoddart, T., 610
Stohr, O., 101
Stone, L., 396
Stone, L. J., 244
Stone, W. L., 251
Stoolmiller, M., 396, 538
Stormshak, E., 524
Story, M., 124
Stouthamer-Loeber, M., 580, 585
Stover, C. S., 585
Strand-Brodd, K., 175
Strauch, B., 86
Strauss, M. S., 183
Strauss, R. S., 124
Strayer, J., 419
Streeter, L. A., 226
Streissguth, A. P., 62
Streri, A., 187
Striano, T., 417, 440
Striepens, N., 572
Strohmeier, D., 542
Strosberg, R., 237
Strough, J., 611, 626
Stuewig, J., 372, 393, 581
Stukas, A. A., 575
Sturaro, C., 541
Sturge-Apple, M. L., 494
Styfco, S. J., 320
Su, Y., 474
Suanda, S., 287, 293
Subbotsky, E., 282
Subrahmanyam, K., 529, 623
Substance Abuse and
Mental Health Services
Administration, 63
Suchday, S., 461
Suchindran, C., 453
Suddendorf, T., 440
Suess, P. E., 406
Sugimoto, T., 185
Sullivan, H. S., 513, 549
Sullivan, K., 269
Sullivan, M. W., 73, 202, 388,
391, 392, 397
Sulloway, F. J., 105
Sumter, S. R., 518
Sun, Y., 491, 540
Sundara, M., 222
Sundie, J. M., 596
Suomi, S. J., 511
Super, C., 72
Super, C. M., 191
Surian, L., 558
Susman, E. J., 66, 396
Sutfin, E. L., 497
Sutherland, K. E., 491
Sutherland, S. L., 272
Sutton, J. E., 283
Suveg, C., 478
Suzuki, D. T., 89, 101, 103

N A M E I N D E X n NI-17
Westenberg, P. M., 518
Westerman, M. A., 419
Westinghouse Learning
Corporation, 318
Weston, D. R., 80
Westra, T., 191
Wheeler, L., 538
Whigham, M., 623
Whishaw, I. Q ., 108
White, B. L., 388
White, K. S., 528
White, L. K., 407
White, M. I., 523
Whitehead, J. M., 622, 624
Whitehead, K. A., 452
Whitehurst, G. J., 327
Whiteman, V., 487
Whitesell, N. R., 515
Whiteside, M. F., 493
Whiteside-Mansell, L., 476
Whiting, B. B., 18, 522, 573, 574,
607, 609
Whiting, J. W., 573, 574
Whitley, B. E., 616
Whitney, M. P., 72
Whitson, S. A., 406
Wichstrom, L., 396
Wickrama, K. A. S., 490
Widen, S. C., 417, 418
Widom, C. S., 584
Wiesner, M., 397
Wigfield, A., 334, 461, 622
Wiggers, M., 418
Wilgenbusch, T., 616, 622
Wilk, S. L., 307
Williams, E. M., 206, 290
Williams, L., 271
Williams, S., 87
Williams, T., 631
Williams, V., 87
Willinger, M., 61
Willis, C., 270
Willoughby, T., 529
Wilsher, C., 74
Wilson, B. J., 374
Wilson, E. O., 572
Wilson, M., 487
Wilson, M. I., 365
Wilson, N., 576
Wilson, P. T., 327
Wilson, R., 244
Wilson, S. P., 151
Wilson, T. D., 348
Wimmer, H., 326
Winberg, J., 55
Windle, M., 531
Winner, E., 269, 306
Winsler, A., 157
Winter, M. A., 494
Wisco, B. E., 397
Wang, J.-L., 529
Wang, L., 540
Wang, M., 402, 403, 410, 477, 478
Wang, M. C., 623
Wang, M.-T., 453
Wang, Q ., 158, 368, 415, 463
Wang, X., 56
Wang, Y., 468
Wang, Z., 540
Ware, E., 197
Wargo Aikins, J., 534
Warkentin, V., 440
Warneken, F., 570, 575
Wartella, E. A., 373
Washburn, J. J., 576
Wasserman, S., 207
Wasserstein, S., 394
Waterman, A. S., 448
Waters, E., 388
Waters, H. S., 147, 329
Watson, J., 10, 36, 88, 269
Watson, J. B., 349–350, 356, 380
Watson, M., 576
Watson, M. W., 584
Watson-Gegeo, K. A., 224
Watt, H. M. G., 621
Waxman, S. R., 239, 241, 265
Way, N., 451, 516, 524
Webber, J., 538
Weber, E. K., 564
Webster-Stratton, C., 503, 538
Weems, C. F., 395
Wegner, D. M., 348
Weinberg, M. K., 388
Weinburgh, M., 616
Weiner, T., 196
Weinert, F. E., 152
Weinstein, S. M., 394
Weis, R., 375
Weiskopf, S., 175
Weiss, B., 584
Weiss, L. G., 313
Weiss, R. J., 630
Weissman, M. D., 276
Weisz, J. R., 401
Wellborn, J. G., 461
Wellman, H. M., 262, 266–269,
275, 419
Welsh, D. P., 531
Wenner, J. A., 347
Wentworth, N., 287
Wentzel, K. R., 537, 540
Werebe, M. J. G., 514
Werker, J. F., 182, 222, 223, 226,
227, 237, 239
Werner, E. E., 2
Werner, L. A., 182
Werner, N. E., 586, 631
West, J., 323
West, M. J., 250, 440
Vikan, A., 282
Visser, G. H. A., 51
Vitaro, F., 521, 541, 581, 630
Vittori, J. M., 587
Voeten, M., 526
Vohr, B. R., 77
Volbrecht, M. M., 572
Volkova, A., 184
Vollebergh, W., 518
Volling, B. L., 489, 500, 567
von Bank, H., 527
von der Lippe, A. L., 479
von Grünigen, R., 542
von Hofsten, C., 164, 189, 191,
193
von Stumm, S., 307
Vondra, J. I., 437
Voos, A. C., 270
Vosniadou, S., 262
Votruba-Drzal, E., 502–504
Vouloumanos, A., 223, 239
Voyer, D., 616
Vygotsky, L. S., 156–158, 168,
244, 512, 513, 517, 525, 549,
550
Wachtel, G. F., 237
Waddell, S., 481
Wadsworth, S. J., 328
Wagner, R. K., 323, 326
Wahlberg, K.-E., 11
Wahlsten, D., 103
Wai, J., 306, 314
Wainright, J. L., 497
Wainryb, C., 565
Wakefield, A. J., 95
Wakeley, A., 290
Wakschlag, L. S., 486
Walbek, N. H., 574
Walden, T., 372
Waldfogel, J., 498, 499, 503
Waldman, I. D., 572, 583
Waldrip, A. M., 518
Waldron, S., 335
Walk, R. D., 196
Walker, B. E., 52
Walker, C. M., 183
Walker, K., 461, 463
Walker, L. B., 183
Walker, L. J., 561
Walker, P., 187
Walker, R. R., 475
Walker, S., 537, 539
Walker-Andrews, A. S., 187, 416,
417
Wall, J. A., 586
Waller, E. M., 520, 535, 614
Wallerstein, J. S., 492, 494, 496
Wallman, J., 219
Wang, D., 468
Valeski, T. N., 25
Valiente, C., 409, 524, 583
Valkenberg, P. M., 529, 530
Vallortigara, G., 185
Vamvakoussi, X., 262
Van, S. R., 624
van Aken, M. A. G., 472
van Balen, F., 497
van Beek, Y., 421
Van de Gaer, E., 624
van den Boom, D. C., 20
Van den Eijnden, R. J. J. M., 529
Van den Oord, E. J., 312, 587
van der Lely, H. K. J., 251
van der Meer, A. L. H., 181
Van Doesum, K. T., 31
van Dolderen, M. S. M., 421
Van Doorn, M. D., 471
van Geert, P., 166
Van Gogh, V., 194
Van Heugten, M., 232
van Honk, J., 583
Van Houtte, M., 624
van IJzendoorn, M. H., 74, 98,
377, 410, 437
van Lier, P. A. C., 542, 580
van Lieshout, C. F., 418
van Loosbroek, E., 289
Van Ryzin, M. J., 585
van Wermeskerken, M., 283
van Winkle, B., 528, 587
van Zalk, M. H., 520
Vandell, D. L., 483, 502–504
Vandenbelt, M., 486
Vandenberg, B., 272
Vandewater, E. A., 373
Vanfossen, B., 586
Vannatta, K., 533
Vaquera, E., 524
Varendi, H., 55
Vasey, P. L., 599
Vaughan, C. C., 48
Vaughn, B. E., 535
Vazquez, D., 397, 407
Veenstra, R., 534
Velleman, S. L., 95
Vellutino, F. R., 323, 326
Ventura, S. J., 64
Vera, E. M., 451
Vereijken, B., 195
Verissimo, M., 545
Verma, S., 481, 522
Vermigli, P., 539
Vermulst, A., 532
Vernon, L., 458
Vernon, P. A., 299
Véronneau, M.-H., 540
Verschueren, K., 460
Vevea, J., 313
Viding, E., 579

NI-18 n N A M E I N D E X
Zeman, J., 421
Zentner, M. R., 184
Zerbinos, E., 605
Zerwas, S., 196, 514
Zevenbergen, A. A., 327
Zevin, J. D., 117
Zhai, F., 503
Zhan, G. Q ., 573
Zhang, D.-J., 529
Zhang, S., 468
Zhang, T.-Y., 98
Zhang, W., 468
Zhang, X., 251
Zhang, Z., 583
Zhou, H., 479
Zhou, Q ., 474, 476, 546
Zickuhr, K., 529
Ziegler, J. C., 251
Zigler, E., 320, 504
Zimmer, E. Z., 54
Zimmer-Gembeck, M. J., 399,
400, 460, 531, 532
Zimmerman, F. J., 240
Zimmermann, P., 411
Ziol-Guest, K. M., 307, 500
Ziv, Y., 347
Zlotnick, C., 481
Zoller, D., 411
Zucker, K. J., 598
Zumbahlen, M. R., 162, 400, 470
Yonas, A., 181, 182
Yoshikawa, H., 316
Young, C. B., 334
Young, M. F., 284
Young, S. K., 572
Youngblade, L. M., 272, 439, 499,
500, 546
Youniss, J., 471, 512, 515, 516,
518, 575, 614
Yu, C., 239
Yuan, S., 239
Yufa, J., 101
Yuill, N., 557
Zachrisson, H. D., 502
Zadnik, K., 29
Zahn-Waxler, C., 392, 393, 415,
567, 570, 571, 574, 576
Zakay, D., 288
Zakhireh, B., 571
Zalewski, M., 478
Zani, B., 531
Zappulla, C., 540
Zarbatany, L., 519
Zatorre, R. J., 220
Zeidner, M., 385
Zeiss, C., 500
Zelazo, N. A., 192
Zelazo, P. D., 149, 165
Zelazo, P. R., 192, 389, 391
Wright, P. A., 396
Wu, L., 184
Wu, P., 476
Wu, S. S., 334
Wu, X., 411, 437, 545
Wynn, K., 210, 260, 289, 290
Wynne, L. C., 11
Xie, H., 578
Xu, F., 32, 204, 205, 243, 292
Xu, L. M., 95
Xu, Y., 539, 583, 584
Xue, Y., 324, 536
Yamada, H., 565
Yamagata, K., 254
Yaman, A., 581, 584
Yang, C., 582
Yang, S.-J., 458
Yang, Y. T., 68
Yap, M. B., 397
Yarrow, M. R., 574, 576
Yates, M., 575
Yau, J., 476, 565
Ybarra, M. L., 631
Yeager, D. S., 360
Yeates, K. O., 357
Yip, T., 453, 462
Yirmiya, N., 501
Yoder, P. J., 251
Wise, N., 378
Witherington, D. C., 278, 387,
390
Withers, G. S., 116
Witherspoon, D., 462
Witkiewitz, K., 581
Witkowska, E., 631
Wittmann, B. C., 167
Witvliet, M., 526
Wolf, M. M., 352
Wolfe, D. A., 531
Wolfe, S. M., 481
Wolfer, L. T., 499
Wolff, P. H., 388
Wolitzky-Taylor, K. B., 631
Wolpert, L., 45, 46
Wood, C. C., 225
Wood, D., 159, 160
Wood, J. L., 528
Wood, J. N., 289
Wood, W., 597, 607
Woodhouse, S. S., 536
Woodward, A. L., 208, 209, 237,
238, 241
Woodward, L. J., 543
Woody, E., 540
Woolley, J. D., 282
Wootton, J. M., 585
World Health Organization, 76
Wright, J. C., 372, 605

SI-1
Bold page numbers indicate material in tables and figures.
Subject Index
Abecedarian Project, 318–319, 319, 663
Abortion, spontaneous. See Miscarriages
ABSL. See Al-Sayyid Bedouin Sign Language
Abstract thinking, 138, 141–142
Abstraction, counting and, 291
Abuse. See Child maltreatment
Academic achievement
child care quality and, 499, 504, 505
cultural influences on employment and, 314,
314–315
early knowledge of numbers and, 154, 306
gender differences in, 619–625
IQ as predictor of, 306, 307, 307–308
media use of children and, 375
peer status as risk predictor with, 540–541,
541
peer support for, 623–624
poverty and, 19
secure attachment and, 438
See also Education
Accommodation, in Piaget’s cognitive
development theory, 133
Accutane (isotretinoin), 60
Acetaminophen (Tylenol), 60
Achievement, ethnic identity, 452
Achievement motivation, Dweck’s theory of,
359–361
Actions, centrality of, 164–165
Activating influences, gender development
and, 598
Active child, as developmental theme, 641–
644
attachment and, 427
biology and behavior and, 86, 97–98
children contributing to own development
in, 12–13, 643
cognitive development and, 131, 135–138
conceptual development and, 260
emotional development and, 385
friendship and, 98
gender development and, 595
individual differences shaped by, 21
infants and, 173
instrumental, operant conditioning and,
201–202
intelligence and, 299, 310
language development and, 12, 216
moral development and, 555
parenting styles and practices shaped by,
477
peer relationships and, 512
Piaget’s cognitive development theory and,
131
play and, 12–13, 98
prenatal development and, 40
questions about, 10
reactions from other people elicited by, 644
self-initiated activity, 642–643
self-regulation and, 643–644
sensorimotor stage of cognitive development
and, 135–138
social development theories and, 341, 362
Active effects, of genotype, 310
Active isolates, 536
Activity level
gender differences in, 625
temperament dimension, 404, 405
See also Motor development
Addition
cognitive development and, 153
commutative law of, 333
counting-on strategy and, 34
infant’s understanding of, 290, 290–291
information-processing theories and, 153
memory and, 152
strategy choices for, 330
ADHD. See Attention-deficit hyperactivity
disorder
Adjustment problems, peer status and risk of,
541, 541–543, 542
Adolescence and adolescents
aggressive-antisocial children and, 581–582
alcohol abuse and, 521–523
antisocial and illegal behavior of, 554,
578–579
autonomy in, 471
birth rates among, 486–487, 488
brain development in, 113, 114
cliques and social networks in early, 526–
528, 531
communication outlets of, 529–530, 530
conception of self development in, 443–446,
444
crowds in, 527–528
cyberbullying and, 529–530
depression in, 395–397
discrimination awareness and, 451
divorce impact on, 490, 492
drug abuse and, 521–523
egocentrism in, 443–444
Erikson’s psychosocial development theory
and, 346–347
ethnic identity in, 451–453
family dynamics in, 471
formal operational stage and, 135, 141–142,
143
friendship in, 516, 518, 518, 524–525
gangs and, 528, 586, 586
gender development milestones in, 612, 614
gender differences in
appearance concerns, 460, 460, 618
depression, 396, 396
physical growth, 618–619
gender-typed behavior in, 612, 614
growth during, 16, 16, 119–120
height changes during, 119, 119–120
homelessness in, 481
identity formation in, 446–449
imaginary audience and, 444
incentive motivation and, 403
juvenile delinquency and, 581
multiple selves and, 443–446, 445
negative emotions increasing during, 394
obesity and, 123, 123–124
parent–child relationship during, 471
as parents, 64, 486–487
peer pressure and, 521–522, 586
planning improvements in, 400
play and rules of, 13
popularity in, 534–535
poverty and, 19
pregnancy and, 64, 486–487
problem solving improvements in, 400
puberty and, 453, 618
reading skills of, 323
romantic relationships and, 531–532
runaways in, 481
social media use of, 529–530, 530
stepparent challenges with, 495
temperament of, 581–582
violence with antisocial behavior in, 577–
579, 579
Adoption studies
design of, 100
Romanian orphans, 6–7, 116, 427, 640
schizophrenia and, 11
Adoptive twin study, 100
Adrenarche, 619
Adult models of attachment, 432–433, 433
Affiliation, 594, 611
Affluence, developmental challenges with,
377–378
Affordances, in perceptual learning, 199–200

SI-2 n S U B J E C T I N D E X
social cognition and, 582
socialization and, 521, 583–586
victimized children and, 542–543
Aggressive-antisocial children and adolescents,
581–582
Aggressive-rejected children, 535–536,
541–542
AIDS, 65
Ainsworth’s Strange Situation, 430, 430–433,
434
AIS. See Androgen insensitivity syndrome
Alaska (Inuit), sex selection of children, 44
Alcohol abuse
adolescents and, 521–523
FAE and, 62
FAS and, 62, 62
FASD and, 46, 62
friendship and, 521–523
genetics and, 522–523
prenatal development and, 46, 60, 62, 62–63
Alleles, 92–93
Al-Sayyid Bedouin Sign Language (ABSL),
249
Altruistic motives, 569
Ambivalent (insecure/resistant) attachment,
431
American Academy of Pediatrics, 504
American Public Health Association, 504
American Sign Language (ASL), 115, 218,
221, 227, 230
Amniotic fluid, 46, 52, 53, 55, 62, 67
Amniotic sac, 47, 48
Anal stage, in Freud’s psychosexual
development theory, 344
Analogical reasoning, 158
Analytic abilities, successful intelligence and,
321
Ancient Greece, child development and, 7–9,
41–42
Androgen insensitivity syndrome (AIS), 599
Androgens, 598–599
Anemia, sickle-cell, 94
Anger
development of, 391–392, 392
emergence of, 386, 387
positive alternatives to, 4
recognition of, 418
strategies for managing, 3–4
“turtle technique” for management of, 4
Animals
children’s fascination with, 273–278
imaginary, 265–266, 266
See also Primates, as test subjects
A-not-B error, 136–137, 137, 165
Anti-bullying interventions, 589
Antisocial behavior, 577–590
adolescent illegal behavior and, 554, 578–579
CD and, 580
characteristics of, 581–582
consistency in, 579–581
prenatal development and, 64
qualitative differences by, 14
Romanian orphan adoption outcomes and,
6–7
romantic relationships by, 531
self-disclosure to friends and parents by, 518,
518
sexual minority youth recognition of sexual
attraction by, 455, 455
sleep patterns by, 72
social judgment domain differentiation by,
564
social scaffolding quality and, 160
temperament and, 406
understanding emotional causes and
dynamics by, 418–419
Aggression
African Americans and self-protection with,
416
characteristics of, 581–582
consistency in, 579–581
controversial children and, 539
cultural influences on, 573
definition of, 577
development of, 577–579
direct, 628
divorce and, 494
Fast Track intervention program for, 588–
589, 589
friendship causing, 521
gender differences and, 578–579, 579,
628–633
by age, 628
biological influences on, 629
cognitive and motivational influences on,
629–630
cultural influences on, 632–633
media influences on, 631–632
parental and other adult influences on, 630
peer influences on, 631
genetics and, 583
genotype–environment interaction and, 96,
96–97
high self-esteem and, 458–459
hostile attributional bias and, 358, 372
indirect, 628
individual selection and, 521
instrumental, 578
neglected children and, 537
origins of, 582–587
biological factors, 583
peer influence and, 586–587
parental conflict and, 585
peer-nominated aggression by age, 579, 579
popular children and, 534–535
preschoolers and, 578
proactive, 582
reactive, 582
rejected children and, 535–536, 541–542
relational, 535, 578, 586
Africa, research in
Beng people, life beginnings and, 41
emotional development and, 414
gender-role flexibility and, 613
motor development milestones and, 191
peer relationship experience in, 522–523
picture perception in, 183
speech perception in, 226
African Americans
aggression and self-protection with, 416
authoritarian parenting styles of, 475–476
in Carolina Abecedarian Project, 318–319,
319, 663
community-of-learners program and, 161
emotional development and, 416
face preferences of, 177
illegal drugs and, 63
infant mortality and, 75
IQ and
group differences with, 315
heritability of, 104
poverty intervention programs boosting,
317
LBW babies of, 76
obesity and, 123
parental warmth of, 476
peer relationship experience in, 522–523
positive ethnic identity and, 452
Project Head Start and, 318
self-esteem and, 462–463
SES of, 19, 19, 80
sickle-cell anemia and, 94
SIDS and, 61
stepparents and, 496
Age
aggression gender differences by, 628
to begin education, 8–9
body composition changing by, 120
brain damage and recovery by, 117–118, 118
continuity/discontinuity with physical
growth by, 16, 16
cross-sectional design comparing, 32–34
display rules and, 421, 421
divorce and child’s, 491–492
of first marriage, 469, 485
friendship determination by, 515–517
genetic influence by, 102
information-processing theories and speed of
processing with, 152, 152–153
intelligence changes by, 298, 309, 309
IQ comparisons by, 305, 313, 313
language development furthering with, 246
methylation and, 98
motor development milestones and, 162–
163, 190, 190–191
older parents and, 488–489
peer-nominated aggression by, 579, 579
perceptual narrowing and, 185, 187–188
positive emotion by, 389
at pregnancy, 2–3, 64, 485–489, 488

S U B J E C T I N D E X n SI-3
music perception and, 184–185
prenatal development and, 53–54, 55–56, 64
prenatal exposure to occupational hazards
and, 64, 64
speech perception and, 224–228
timing and, 639
word segmentation and, 228–229
Auditory localization, 182
Australia, research in
father interactions with children in, 482–483
peer relationship expectations in, 523
spatial ability and, 286
Authoritarian parenting styles, 473, 473, 474
African Americans and, 475–476
SES and, 479
Authoritative parenting styles, 473, 473–474,
575
in China, 476
European Americans and, 476
SES and, 479
Autism spectrum disorder (ASD)
drawing and, 255, 255–256
false-belief problems and, 270
language development and, 251
regulator gene defects and, 95
theory of mind and, 270
Autobiographical memories, 160
Autonomous adults, parental attachment
status, 432, 433
Autonomous morality, Piaget’s stage of, 557
Autonomy, Erikson’s psychosocial
development theory, 346
Axons
growth of, 110–111
structure and function of, 106, 107
Babbling, 230, 230–231
Baby-sitting, gender-role flexibility and, 613
Balance scale study
information-processing theories and, 150
Piaget’s, 139, 139
Baldness, male-pattern, 94
Bali, United States childbirth practices
compared to, 68–69
Bandura’s social cognitive theory, 352–354
Basic level, category hierarchies, 263, 264–265
Basic processes, in information-processing
theories, 150, 150–151, 651
Basic trust, Erikson’s psychosocial
development theory, 346
Battered children. See Child maltreatment
Behavior genetics
definition of, 99
environmental effects and, 104–105
family studies and, 99–102, 101
heritability analysis with, 102–104
research designs in, 99–102
Behavior modification, 351–352
Behavioral cycles, in prenatal development, 52
Behavioral inhibition, temperament and, 409
child care programs and, 501–502
cultural variations in, 434
definition of, 427
genetics and, 661
Harlow’s primate research and, 427–428
individual differences and, 427, 432–433,
436–437, 658
internal working model of, 429, 437
interventions for parental sensitivity and, 436
long-term effects of, 437–439
measurement of, 430–433
nature and nurture and, 427
parental sensitivity and, 435–437
parental status of, 432–433, 433
peer relationships with social competence
and parental, 544–545
phases of, 429
sociocultural context and, 427
Strange Situation and, 430, 430–433, 434
theory, 428–430
types of
ambivalent, 431
disorganized/disoriented, 431–432, 435,
436
insecure, 431, 438
insecure/avoidant, 431, 437
insecure/resistant, 431
See also Secure attachment
Attachment theory, 428–430
Attachment-in-the-making, 429
Attention
effortful, 16–17
finger pointing and, 231
of infants and faces, 12, 175–177, 176, 177,
187
joint, 159, 159, 231
reinforcement and, 351
selective, information-processing theories,
151
Attention span, temperament dimension, 404,
405
Attention-deficit hyperactivity disorder
(ADHD), 589
definition of, 370
environmental factors of, 370
genetics and, 370
ODD and CD with, 580
parents contributing to, 370
polygenic inheritance of, 94
Ritalin and treatment of, 370–371
Attractiveness
bias with, 177
infant preferences with faces and, 177
parenting style influenced by, 477
peer status and, 533, 534
self-esteem and, 460
sexual, 453, 455, 455
Auditory development and preferences
infant perception and, 182, 184–185
labeling tones of voice and, 417
covert behavior and, 578
cultural influences and, 573
development of, 577–579
Fast Track intervention program for, 588–
589, 589
gender differences in, 578–579, 579
genetics and, 587–589
as heritable, 103
ineffective discipline with, 584–585
juvenile delinquency and, 581
ODD and, 580
parental conflict and, 585
parental punitiveness with, 584–585
SES and, 585–586
social cognition and, 582
socialization of, 583–586, 587–589
temperament and, 581–582
violence in adolescent, 577–579, 579
See also Aggression
Apoptosis, 46, 47
Approval and/or stereotyped orientation, in
prosocial behavior, 563
Arborization, of dendrites, 111–112
Arithmetic
conceptual understanding of, 333–334
counting and, 291, 291–292, 292, 331
numerical magnitude representations and,
332, 332–333, 333
strategies for learning, 330–331, 330–331
See also Mathematics
ASD. See Autism spectrum disorder
Asian Americans
coming out acceptance challenges with,
456–457
face preferences of, 177
self-esteem and, 463–464
See also Chinese Americans
ASL. See American Sign Language
Asperger syndrome, 95
Assertion, 594, 611
Assimilation
ingroup, 603
in Piaget’s cognitive development theory,
133
Association areas, of brain, 109
At-risk children
biological and environmental risks with, 2–3
divorce and, 489
intellectual development of, 315–317, 316
multiple-risk model for, 79–80, 80
research and children’s welfare implications
for, 662–664
resilience and, 2–3, 80
See also Child maltreatment; Interventions,
for at-risk children
Attachment, 425–465
active child theme and, 427
adult models of, 432–433, 433
Bowlby’s theory of, 426, 428–429
caregiver–child relationship and, 427–439

SI-4 n S U B J E C T I N D E X
Breastfeeding, 121, 121
Breathing, fetal, 52
Brief transitions, in Piaget’s cognitive
development theory, 134
Broad applicability, in Piaget’s cognitive
development theory, 134
Bronfenbrenner’s bioecological model of social
development. See Bioecological model of
social development
Bullying, 529–530, 589
CAH. See Congenital adrenal hyperplasia
Cardinality, counting and, 291
Caregiver. See Parents and caregiving
Carolina Abecedarian Project, 318–319, 319,
663
Cataracts, in infants, 115
Categorical perception, 224–226, 225, 226
Category hierarchies, 263, 263–265
Causality
conceptual development and, 279–282
correlation in research and, 29–30
early causal reasoning, 279–281
empiricist views on, 279
gestures and, 334
imitation and, 280, 280
magical thinking and, 282
nativist views on, 279
object categorization and understanding of,
265–266, 266
preschoolers and, 281
triadic model of reciprocal causation, 603
CD. See Conduct disorder
Cell body, 106, 106
Cell differentiation, 45
Cell division, 45
Cell migration, 45, 648
Central developmental issues
cognitive development and
dynamic-systems theories, 165–166
information-processing theories, 147–153,
155
Piaget’s theory, 133–135
sociocultural theories, 158–160
social development
ecological theories of development on, 362
learning theories on, 349
psychoanalytic theories on, 342
social cognition theories on, 356–357
Centration, preoperational stage of cognitive
development, 139–141, 288
Cephalocaudal development, 48, 120
Cerebral cortex
depression and, 395
language development and, 220
lobes in, 108, 108–109
spatial reasoning in, 283
structure and function of, 108, 108–109
visual processing and, 173–174
Cerebral hemispheres, 109, 220
Bisexual youth. See Sexual minority youth
Bitter tastes, food preferences, 122
Blindness, 115–116, 285
Bobo doll, 352–353, 353, 354
Bodily-kinesthetic intelligence (Gardner), 321
Body composition, age and, 120
Body image, 618
Bowlby’s attachment theory, 426, 428–429
Boys compared to girls. See Gender differences
Brain
adolescent development of, 113, 114
association areas of, 109
cerebral cortex of
depression and, 395
language development and, 220
lobes in, 108, 108–109
spatial reasoning in, 283
structure and function of, 108, 108–109
visual processing and, 173–174
cerebral lateralization and, 109
connectivity among regions of, 151
damage and recovery of, 117–118, 118
development of, 106–118
developmental processes of, 109–113
dyslexia studies with, 326
effortful attention and, 17
experience and, 114–117
experience-dependent processes, 116–117
experience-expectant processes, 115–116
FAS and, 62, 62
FASD and, 46, 62
fetal, 47, 47, 50, 56
gender development functioning of, 598–599
gender differences and structure of, 621
glial cells and, 107–108
gray matter of, 106
human sizes of, 364, 364
language development and, 219–221
mapping, 110–111
mechanisms of developmental change in,
648–649
memory control of, 148, 148
motor development and maturation of, 191
myelination and, 112, 151, 648
neural tube development and, 47, 47
neurogenesis and neuron development in,
109–112, 648
neuroimaging, 110–111, 111
neurons, 106–107, 107, 109–112, 204
plasticity of, 114–116, 118
primate sizes of, 364
REM sleep and activity of, 71
sensitive periods of, 116
structures of, 106–109
synapse elimination and, 113, 114
synaptic pruning and, 113, 649
synaptogenesis and, 112, 112–113, 648–649
Brainology program, 22
Brazil, research in, 565–566
Breast milk, 121
Behaviorist theory, 10
classical conditioning, 201
conditioning and development process in,
349–350
instrumental, operant conditioning, 201,
201–202, 350–352
parent responsibility in, 350
Beliefs, theory of mind and, 267–271
Beng (Ivory Coast, Africa), prenatal
development and, 41
Best friendship, reciprocated, 520–521
Bias
attractiveness and, 177
China’s one-child policy and gender, 468–469
gender schema theory and, 601–602
hostile attributional, 358, 372
ingroup, 603
in interviews, 26
shape, 239, 239
in valuing gender of offspring, 44
Bicultural identity, 453
Bidirectionality of parent–child interactions,
478, 478–479
Bilingualism, 222
Binet-Simon Intelligence Test, 298
Binocular disparity, 181
Bioecological model of social development
(Bronfenbrenner), 17–18, 366–378
child maltreatment and, 369–372
children and media and, 372–376
cultural influences and, 368
current perspectives on, 378–379
environmental systems in, 366–369, 367
gender development and, 606–607
mesosystem in, 367, 368
microsystem in, 367, 367–368
SES development effects and, 376–378, 377
“A Biographical Sketch of an Infant”
(Darwin), 9
Biology
acquisition of knowledge of, 277–278
informal theory of, 262–263
preschooler knowledge of living things and,
273–278
understanding processes of, 275–277
Biology and behavior, 85–127
active child and, 86, 97–98
continuity/discontinuity and, 86
genetic and environmental forces in, 88–99
individual differences and, 86, 102
mechanisms of developmental change and,
86, 648–649
nature and nurture and, 86, 87–105
understanding, 86
Biosocial theory, of gender development, 597
Birth. See Childbirth
Birth rates
adolescents and, 486–487, 488
gender differences in, 44, 44
outside marriage, 486, 488

S U B J E C T I N D E X n SI-5
Clear-cut attachment, 429
Cleft palate, 49
“Climber” animation test, 210, 210–211
Clinical interview, 25–26, 28
Cliques
in adolescence, 526–528
dynamics of, 527
in early adolescence, 526
negative influences of, 528, 531
Coaching, parents and, 546–548
Cocaine, 63
Cognitive development, 129–168
active child theme and, 131, 135–138
addition and, 153
central developmental issues and
dynamic-systems theories, 165–166
information-processing theories, 147–153,
155
Piaget’s theory, 133–135
sociocultural theories, 158–160
child care and, 503–504
child’s nature, views of
dynamic-systems theories and, 163–165
information-processing theories and,
146–147
Piaget’s theory and, 132–133
sociocultural theories and, 156–158
concrete operational stage of, 135, 141, 143
continuity/discontinuity in development
and, 15
definition of, 15
empiricist views on, 206
formal operational stage of, 135, 141–142, 143
friendship and, 519
gender differences in, 619–625
of infants and toddlers, 205–211
future study of, 211
object knowledge, 206–207
physical knowledge, 207–208, 208
social knowledge, 208–211, 209, 210
support relations understood in, 207–208,
208
Kohlberg’s theory on gender development
and, 600
main questions addressed by theories of, 131
malnutrition and, 124–125, 125
mechanisms of developmental change and,
144, 651–653
nativist views on, 205–206
perception and, 205–211
practical benefits of theories of, 130–131
preoperational stage of, 135, 138–141, 143
processing limitations in, 146
sensorimotor stage of, 135–138, 143
sociocultural context and, 654–655
See also Dynamic-systems theories;
Information-processing theories;
Piaget’s cognitive development theory;
Sociocultural theories of cognitive
development
genotype–environment interaction and, 96,
96–97
LBW babies and, 78
prevention programs for, 373
sexual minority youth and, 457
stepparents, Cinderella effect and, 365, 365
Child witnesses, public policy and, 4–5,
665–666
Childbirth
in Bali compared to United States, 68–69
complications and outcomes with, 2
cultural influences on practices of, 68–69, 69
drug use for delivery in, 67, 68
initiation of, 66–67
negative outcomes with, 74–81
training for, 68
Children
knowledge acquisition theories and, 8
in poverty, 19–20, 376–377, 377
raising, 3–4
shaping own development, 12–13
spanking, 3
See also specific topics
Child’s nature, views of
cognitive development
dynamic-systems theories on, 163–165
information-processing theories on, 146–147
Piaget’s theory on, 132–133
sociocultural theories on, 156–158
social development
ecological theories of development on, 362
learning theories on, 349
psychoanalytic theories on, 342
social cognition theories on, 356
China, research in
authoritative parenting style in, 476
children as product of culture and, 158
counting in, 291–292, 292
dyslexia and, 117
emotional development and, 414–415
IDS in, 223
motor development milestones and, 190–191
one-child policy in, 468–469
peer status and, 540
rapid modernization and health in, 63
separation anxiety and, 391
sex selection of children and, 44
Chinese Americans
discipline of, 654
emotional development of, 414
See also Asian Americans
Chromosomes, 42, 44, 89–90, 92–93, 94
Chronosystem, in bioecological model, 367,
368–369
Chutes and Ladders game, 154
Cigarette smoking, 60, 61
Cinderella effect, child maltreatment and, 365,
365
Circadian rhythms, 52
Classical conditioning, 201
Cerebral lateralization, 109
Cesarean deliveries, 68
Change as theme. See Mechanisms of
developmental change
Character, building, 8
Child care and child care programs
academic achievement and quality of, 499,
504, 505
adjustment and socialization in, 502–503
attachment and, 501–502
cognitive development and, 503–504
family characteristics impact on, 502
language development and, 503–504
maternal employment and, 498–504, 505
minimum standards for, 504
public policy issues with, 665
risks and benefits of, 500–501
SES and, 503
sociocultural context and, 18
staff characteristics in good, 505
United States families changes and trends in,
500, 500
Child custody, 493
Child development, introduction to, 1–37
designs for examining, 32–34, 35
ethical issues in research of, 35
historical foundations of, 7–10
human nature understanding as reason for
learning about, 6–7
intelligence and study of, 21
methods for study of, 22–36
parents and caregiving as reason for learning
about, 3–4
philosophers’ views of, 8–9
public policy issues as reason for learning
about, 4–5
purpose of studying, 3–7
research benefits with, 21–22
research-based theories of, 10
themes in, 10, 10–22
active child as, 10, 12–13
continuity/discontinuity as, 10, 13, 13–16,
16
individual differences as, 10, 20–21
mechanisms of developmental change as,
10, 16–17
nature and nurture as, 10, 10–12
research and children’s welfare as, 10,
21–22
sociocultural context as, 10, 17–20, 19
variables in, 28
See also specific development themes
Child Development Project, 576, 665
Child labor, Industrial Revolution and, 9
Child maltreatment
bioecological model of social development
and, 369–372
causes of, 369–371
consequences of, 372
development of, 369

SI-6 n S U B J E C T I N D E X
conception of self and, 647–648
emotional development and, 385
explained, 13, 13–16, 16
Freud’s psychosexual development theory
and, 15
of individual differences, 645–646
infants and, 173
intelligence and, 299, 305
IQ and, 305
moral development and, 555, 561
peer relationships and, 512
physical growth by age and, 16, 16
in Piaget’s cognitive development theory, 15,
131, 133–135
prenatal development and, 40, 51–52
questions about, 10
social development theories and, 342, 349,
356, 362
stage theories of development and, 15, 133–
135, 646–648
time and, 647
Continuous development, 13, 13–16, 16
Contrast sensitivity, 174–175
Control group, 31
Control Signals Poster (CSP), 538
Controlling statements, 627, 627
Controversial children, 533, 537, 539
Conventional moral reasoning, Kohlberg’s
stage of, 559, 559–560
Convergence, pictorial cues, 181
Conversational skills, infant development of,
244–246
Cooperation, in peer relationships, 512, 514
Corpus callosum, 109
Correlation
causality and, 29–30
definition of, 29
of reading hours with reading-test scores, 29
Correlational designs, 28–32, 32
Cortisol, 403, 407
Cortisol reactivity, 407
Co-rumination, depression and, 396, 520, 614
Counting, 291, 291–292, 292, 331
Counting-on strategy, 34
Covert behavior, 578
CR. See Conditioned response
Crawling, 190, 194–197
Creative abilities, successful intelligence and,
322
“Crib speech,” 12
Critical period
definition of, 220
imprinting and, 363
for language development, 220–221, 221
Cross-ethnic friendships, 524
Cross-gender peers, 611
Cross-gender-typed behavior, 595, 598–599
Crossing over, DNA, 91
Cross-sectional designs, 32–33, 35
Cross-situational word learning, 239
Conceptual development, 259–295
active child theme and, 260
arithmetic and, 333–334
empiricist views on, 260–261, 266, 271,
277–279, 283, 289
mechanisms of developmental change and,
260
nativist views on, 260–261, 266, 269–270,
277, 279, 283, 288–289
nature and nurture and, 260–261
sociocultural context and, 260
theory of mind and, 267–271, 268
understanding who or what in, 261–278
knowledge of living things and, 273–278
knowledge of other people and oneself in,
266–272
object categorization and, 261–266
understanding why, where, when, and how
many, 278–294
causality, 279–282
number, 288–293
space, 283–286, 292–293
time, 286–288, 292–293
Concrete operational stage of cognitive
development (Piaget), 135, 141, 143
Conditioned response (CR), 201
Conditioned stimulus (CS), 201
Conditioning
behaviorist theory on development and,
349–350
classical, 201
instrumental, operant, 201–202, 202,
350–352
mechanisms of developmental change and,
649–650
Conduct disorder (CD), 580
Cones, retinal, 174–175
Conflict mitigation strategies, 629
Congenital adrenal hyperplasia (CAH), 599
Connectionism, language development and,
252
Conscience, development of, 555, 566–568,
659–660
Conservation concept (Piaget), 139–141, 140
Consistently responsive caregiving, 435
Consonance, music perception and, 184–185
Constancy
ethnic, 450, 450
gender, 600, 608–609
Constructivist approach, 132
See also Piaget’s cognitive development
theory
Content knowledge, 151–152, 652
Contingency relation, 201–202, 202
Continuity/discontinuity, as developmental
theme
behaviors compared to underlying processes
in, 646–647
biology and behavior and, 86
cognitive development and, 15
Cognitive flexibility, 149
Cognitive strategies, to control negative
emotions, 400
Cognitive theories, of gender development,
599–606
Colic, 74
Collaboration, 594
Collaborative statements, 627, 627
Collective monologues, 244
College/university students
sexual identity and, 454
vocabulary of, 246
Color, infant perception of, 174–175, 264
Color blindness, 94
Columbine tragedy, 554
Coming out
consequences of, 456–458
cultural influences with acceptance of,
456–457
first recognition in, 454–455
identity acceptance and integration in,
456
process of, 454–456, 455
test and exploration period in, 456
Common movement, 179–180
The Common Sense Guide to Baby and Child
Care (Spock), 350
Communication
adolescents’ outlets for, 529–530, 530
collaborative statements in, 627, 627
controlling statements in, 627, 627
conversational skills in, 244–246
early interactions in, 230–231
face-to-face, 529–530, 530
gender differences with, 626–628
gestures in, 230, 248–249, 333–334
intersubjectivity and, 159, 231
joint attention in, 159, 159, 231
obliging statements in, 627, 627
pragmatic development and, 245–246
primates and, 219, 219
SES and family, 479
turn-taking in, 230–231
of values, 574, 574
withdrawal acts in, 627, 627
See also Language development
Community-of-learners program, 161
Commutative law of addition, 333
Complex environments, 116–117
Comprehension
language, 217
reading, 325, 327
vocabulary, 231–232
Comprehension monitoring, for reading,
327
Concentration camp survivor study, of Freud,
Anna, 510–511
Conception, 42–44, 45
Conception of self. See Self, conception of
Concepts, 260–261

S U B J E C T I N D E X n SI-7
Developmental psychology. See Child
development, introduction to
Developmental resilience, 2–3, 80
Diethylstilbestrol (DES), 59
Differential (discrete) emotions theory, 386
Differential susceptibility, 409, 478
Differentiation
cellular, within embryo, 45
perceptual learning and, 199
Difficult babies, 404
Diffusion/foreclosure, ethnic identity, 451
Direct aggression, 628
Direct instructors, parents as, 472
Direction-of-causation problem, 29, 32
Disappearing reflex, 192
Discipline
of Chinese Americans, 654
conscience development and, 567–568
cultural influences on, 475–476
education goal of, 8
ineffective, 584–585
parental punitiveness and, 583–584
parenting styles and, 472–476, 575–576
philosophical history of, 8–9
stepparents and, 495
Discontinuous development, 13, 13–16, 16
See also Continuity/discontinuity, as
developmental theme
Discrete (differential) emotions theory, 386
Discrimination awareness, ethnic identity and,
451
Disease, prenatal development and, 65
Disequilibrium, Piaget’s cognitive
development theory and, 133–134
Dishabituation, 225
Dismissing adults, parental attachment status,
432, 433
Disorders, genetic transmission of, 94–95
Disorganized/disoriented attachment, 431–
432, 435, 436
Display rules, 420–421, 421
Dissonance, music perception and, 184
Distraction, distress regulated with, 73, 399
Distress
development of, 390–391, 391
distraction to regulate, 73, 399
fearful, 404, 405
irritable, 404, 405
response to, 74
separation anxiety and, 391, 391, 420
Distributional properties, of speech, 228–229
Diversity, genetics and, 90–91
Division, cellular, 45
Divorce
adolescents dealing with, 490, 492
age of child at time of, 491–492
aggression and, 494
at-risk children and, 489
contact with noncustodial parents after,
492–493
on siblings relationships, 484
sleeping arrangements and, 18, 18–19
social judgment domains and, 565
soothing practices and, 73–74
on stepparents, 496
telegraphic speech and, 242
understanding causes of emotions and, 418
victimized children and, 542–543
on violence, 632
See also specific ethnic groups; specific groups;
specific nations
Cultural tools, 156, 157
Custody, after divorce, 493
Cyberbullying, 529–530
Cyberspace, peer relationship experiences in,
529–530
Cystic fibrosis, 94
Cytomegalovirus, 65
Darwin’s theory of evolution, 9–10
Data gathering, contexts for
interviews, 25–26, 28
naturalistic observation, 26–27, 28
structured observation, 27–28, 28
Dating violence, 631
Deaf children, language development with,
230, 248–249, 251
Death
as developmental stage, 46
infant mortality and, 74–75, 75
Deconditioning, 350
Deferred imitation, 136, 137
Delay of gratification, 384
Dendrites
arborization and growth of, 111–112
spines on, 111–112, 116
structure and function of, 106, 107
Deoxyribonucleic acid (DNA), 11–12, 89, 91
Dependent variable, 31
Depressed mothers, 30, 436
Depression
in adolescence, 395–397
cerebral cortex and, 395
development of, 395–397
drug treatment for, 397
family factors in, 396
gender differences in adolescent, 396, 396
heredity and, 395
homelessness and, 481
rumination/co-rumination and, 396, 520,
614
symptoms of, 395
Depth perception, 180–182, 181, 182
DES. See Diethylstilbestrol
Designs, for examining development, 32–34,
35
Desires, theory of mind and, 267–268
Determinism, reciprocal, 354, 355
Developmental processes, prenatal
development, 45–47
Crowds, in adolescence, 527–528
Crying, infant
caregiver response to, 72–73
colic condition and, 74
evolution and evolutionary perspective on,
72–73
LBW babies and, 78
newborn states of arousal and, 70, 70, 72–74
soothing for, 73–74, 399
Crystallized intelligence, 300
CS. See Conditioned stimulus
CSP. See Control Signals Poster
Cultural influences
on academic achievement and employment,
314, 314–315
on academic achievement and gender
differences, 624–625
on aggression, 573
on aggression and gender differences,
632–633
antisocial behavior and, 573
attachment and, 434
bilingualism and, 222
bioecological model of social development
and, 368
on childbirth practices, 68–69, 69
children as products of, 157–158
coming out acceptance and, 456–457
on discipline, 475–476
display rules and, 420–421, 421
emotional development and, 414–416
emotional expression control and, 415, 421,
654
of families on children, 470
of father interactions with children, 482–483
first words and, 233–234, 234
on friendship, 515, 522–523
gender development theories with
bioecological model of social development,
606–607
social role theory, 607
gender-role flexibility and, 613
IDS and, 223–224
language components and, 218
moral judgment and, 561
motor development and, 190–191
obesity and, 123
parental beliefs and behaviors and, 421,
475–476
parental gatekeeping and, 547
on parenting styles, 475–476
peer groups and negative, 528, 531
on peer relationships, 522–523
peer status similarities and differences across,
539–540
picture perception and, 183
prenatal development and, 41
prosocial behavior and, 562–563, 573
self-conscious emotions and, 393–394
self-esteem and, 463–464

SI-8 n S U B J E C T I N D E X
Ego, 343
Egocentrism
in adolescence, 443–444
egocentric spatial representations, 284
imaginary audience and, 444
personal fable and, 443–444
preoperational stage of cognitive
development and, 138–139, 139
Electra complex, Freud’s psychosexual
development theory, 345
Electroencephalographic recordings (EEG),
110, 110, 220, 406–407, 407
Embarrassment, development of, 392–393
Embryo
definition of, 45
early development of, 47–48
hand plate of, 46, 46
miscarriages and, 56
Embryonic stem cells, 45
Emotional development, 383–423
active child theme and, 385
in childhood, 385–398
depression, 395–397
differential (discrete) emotions theory, 386
functionalist approach to, 386
identifying emotions of others, 416–418
negative emotions, 3–4, 389–392, 394–395,
400, 412–414, 419
normal, 394–395
positive emotions, 388–389
self-conscious emotions, 392–394
theories on nature and emergence of,
386–387, 387
understanding causes and dynamics of
emotion, 418–419
understanding real and false emotions,
419–421, 420, 421
coaching and, 548
continuity/discontinuity and, 385
cultural influences on, 414–416
divorce influence on, 490–491, 491
family and, 410–414
parental socialization of children in,
411–414
parent/child relationship quality in,
410–411
individual differences and, 385
nature and nurture and, 385
regulation of, 398–410
cognitive strategies to control negative
emotion, 400
heredity and, 402–403
individual differences in, 402–410
selection of appropriate strategies for,
400–401
shift from caregiver to self-regulation,
399–400
social competence and adjustment, 401
sociocultural context and, 385
temperament and, 403–410
novelty preference and, 167
Piaget’s cognitive development theory
compared to, 163–164
selection and, 166–167
self-organization and, 165–166
Dyslexia, 95, 117, 326, 326
Early Start Denver Model (ESDM), 270
Easy babies, 404
Eating
food preferences and regulation of, 122
healthy habits encouraged for, 124
obesity and, 122–124, 123
parent influence on, 122
See also Nutrition
Ecological theories of development, 362–379
bioecological model, 366–379
central developmental issues and, 362
current perspectives on, 378–379
ethology and, 362–363, 378
evolutionary perspective on, 363–366, 379
view of child’s nature, 362
Economic functions, of family, 470
Economic influences on development, family
structure changes and, 485
See also Poverty; Socioeconomic status
Economic stress, parenting styles influenced
by, 480, 480, 482
Education
age for beginning, 8–9
bilingualism and, 222
classroom as community of learners for, 161
continuity of IQ scores and, 305
discipline as goal of, 8
early-intervention programs for, 317–320
family value placed on, 312
information-processing theories applied to,
154
IQ as predictor of academic achievement in,
306, 307, 307–308
jigsaw approach for, 161
philosophical history of, 8–9
Piaget’s cognitive development theory
applied to, 143
research and children’s welfare implications
for, 662
SES influencing parenting styles with, 479
sociocultural theories of cognitive
development applied to, 161
special curriculum, “turtle technique” for, 4
television watching and, 372
writing challenges in, 328–330
See also Academic achievement; Preschool
and preschool-age children; School and
school-age children
EEG. See Electroencephalographic recordings
Effect size, gender differences and, 615, 615,
616
Effortful attention, 16–17
Eggs, female human, 42–44, 43, 91
Divorce (cont.)
custody of child after, 493
emotional development influenced by,
490–491, 491
father interactions with children after,
492–493
as heritable, 103
long-standing behaviors increased with, 493
marital conflict as alternative to, 494
mothers interacting with children after, 493
parental conflict and, 490
potential impact of, 489
stress from, 490–491, 491
United States family changes and trends
with, 486–488, 489–496
Dizygotic twins. See Fraternal twins
DNA. See Deoxyribonucleic acid
Dodge’s information-processing theory of
social problem solving, 357–358
Domain-specific/domain-general language
development, 250–251, 652–653
Dominant alleles, 92
Dominant genes, 92
Dominant–recessive pattern, 92–93
Dopamine, 437
Dose–response relation, teratogens and, 59
Doubt, Erikson’s psychosocial development
theory, 346
Doulas, in birth experience, 68
Down syndrome, 94, 95, 251
Drawing, early, 254, 254–256, 255
DRD4 gene, 437, 588
Drug use/abuse
adolescents and, 521–523
childbirth and, 67, 68
cocaine and, 63
friendship and, 521–523
genetics and, 522–523
marijuana and, 63
nicotine, 60, 61
as prenatal hazard, 59–60, 63
thalidomide, 57–58, 91
See also Alcohol abuse
Dual representation, symbols and, 252,
253–254
Duchenne muscular dystrophy, 94
Dweck’s theory of self-attributions and
achievement motivation, 359–361
Dynamic-systems theories, 144, 161–167
central developmental issues in, 165–166
centrality of action in, 164–165
child’s nature views of, 163–165
definition of, 161, 163
educational applications of, 166
main questions addressed by, 131
mechanisms of developmental change and,
166–167
memory and, 164–165
motivators of development in, 163–164
motor development and, 192

S U B J E C T I N D E X n SI-9
Ethnic identity, 449–453
achievement, 452
in adolescence, 451–453
bicultural identity and, 453
in childhood, 450, 450–451
constancy, 450, 450
definition of, 450
diffusion/foreclosure, 451
discrimination awareness and, 451
feelings and preferences, 450, 450
high self-esteem and positive, 452
knowledge, 450, 450
role behavior, 450, 450
search/moratorium, 451–452
self-identification, 450, 450
See also Race
Ethnicity. See specific groups
Ethology, 362–363, 378
European Americans
authoritative parenting styles of, 476
emotional development of, 414
face preferences of, 177
independence promoted by, 158
infant mortality and, 75
IQ and
group differences with, 315
heritability of, 75, 104
negative peer group influence and, 528, 531
peer relationship experience in, 522–523
Project Head Start and, 318
self-esteem and, 462
separation anxiety and, 391
Event-related potentials (ERPs), 110, 111,
372
Evocative effects, of genotype, 310
Evolution and evolutionary perspective
basic concepts of, 363–364
crying and, 72–73
current perspectives on, 378
Darwin’s theory of, 9–10
ecological theories on development and,
363–366
on gender development, 596–597
genome and, 88
parental-investment theory and, 365
play and, 364–365
Evolutionary psychology theory, 596–597
Executive functions, memory and, 148,
148–149
Exercise, prenatal development and, 66
Exosystem, in bioecological model, 367, 368
Experience-dependent plasticity, 116
Experience-dependent processes, 116–117
Experience-expectant plasticity, 115–116
Experience-expectant processes, 115–116
Experimental control, 30–31, 32
Experimental designs, 30–32, 32
Experimental group, 31
The Expression of the Emotions in Man and
Animals (Darwin), 386
of childhood poverty, 376–377, 377
complex, 116–117
definition of, 88–89
epigenetics and, 98–99
genetics and heredity with
child’s environment–child’s genotype, 89,
98–99
child’s environment–child’s phenotype, 89,
93, 96–97
child’s genotype–child’s phenotype, 89,
91–93
child’s phenotype–child’s environment, 89,
97–98
parent’s genotype–child’s genotype, 89,
89–91
genotype interactions with, 93, 96, 96–97,
309–310
goodness of fit and, 409
heritability and, 87, 104–105
intelligence development and, 308–320
family influences on, 310–312, 311
genotype interactions with, 93, 96, 96–97,
309–310
school influence on, 312–313, 313
shared and nonshared family environments,
312
societal influence on, 313–320
IQ and, 305
language development and, 221, 223–224
negative emotions influenced by, 394–395
nonshared, 105, 312
obesity influences in, 123
parent contributing to child’s, 97, 661
physical growth variables with, 120
pollutants of, 63
poverty hazards of, 59
prenatal development hazards with, 56–64,
59, 117–118
risks and, 315–317, 316
SES and, 87–88
shared, 104–105, 312
spatial ability and external, 285–286
See also Nature and nurture, as developmental
theme
Environmental risk scale, 316, 316
Epidurals, 67
Epigenesis, 42
Epigenetics, 11–12, 17, 98–99, 640–641
Equilibration, in Piaget’s cognitive
development theory, 133–134
Erikson’s psychosocial development theory, 15
current perspectives on, 347–348
development process in, 345–347
identity formation in, 346–347, 446–447
Erogenous zones, 342
ERPs. See Event-related potentials
ESDM. See Early Start Denver Model
Essentialism, 276
Estrogen, 48
Ethical issues, in research, 35
Emotional expression
causes and dynamics of, 418–419
cultural influences on controlling, 415, 421,
654
display rules and, 420–421, 421
facial expression and, 418
IDS and, 223
of infants, 387–397
labeling, 417–418
memory triggering, 419
parental assistance in managing negative,
3–4
of parents, 411–412
parents discussing, 413–414
peer relationships sharing, 524–525
real compared to false, 419–421, 420, 421
speed of, 402
Emotional intelligence, 384–385
Emotional self-regulation, 398–401, 418
Emotional stress. See Stress
Emotions, 385
Empathy, 393, 569–570
Empiricist views
on cognitive development, 206
on conceptual development, 260–261
biological knowledge acquisition, 277–278
causality, 279
knowledge of people and self, 266
number, 289
space, 283
theory of mind, 271
of object perception, 178
Employment
cultural influences on academic achievement
and, 314, 314–315
IQ scores predicting income and, 307,
307–308
maternal
child care and, 498–504, 505
effects of, 498–500, 500
gender differences in influence of, 499–
500
infants influenced by, 498–500, 500
part-time, 500
prenatal occupational hazards and, 63–64,
64
preschool and school-age children
influenced by, 499, 500
United States family changes and trends
with, 498
Enactive experience, 603–604
Encoding, in information-processing theories,
150–151, 152
Entity theory, 359
Entity/helpless orientation, 359
Environment
ADHD factors in, 370
behavior genetics and, 104–105
bioecological model systems in, 366–369,
367

SI-10 n S U B J E C T I N D E X
Fetal alcohol syndrome (FAS), 62, 62
Fetal programming, 59
Fetus
behavior of, 51–52
brain development of, 47, 47, 50, 56
breathing of, 52
definition of, 45
development of, 47–48
face development of, 48–49, 49
facial expression of, 50
father’s voice heard by, 56
gender differences in vulnerability of, 44, 44
habituation of, 54, 54
headplates of, 67, 67
illustrated summary of, 48–51, 48–51
learning prior to birth of, 40, 46, 54–56, 57
memory of, 55
mother’s voice heard by, 54–55
movement of, 49–50, 51–52
sensory experience of, 52–54
sexual differentiation of, 49
speech recognition of, 54–55, 56
swallowing of, 52
sweet taste preference of, 53
See also Prenatal development
Finger pointing, attention and, 231
First recognition, in coming out, 454–455
First sentences, 242
First words, 231–242
cues for, 237–238, 238
cultural influences with, 233–234, 234
grammatical category of, 239
holophrastic period with, 234
intention and, 237–238
learning, 236–241
linguistic context and, 238–239, 239
overextension of, 234, 234–235
production of, 232–235
pronunciation challenges with, 232
recognition of, 231–232
reference problems with, 231
shape bias with, 239, 239
Fixation, in Freud’s psychosexual development
theory, 345
Fluid intelligence, 299–300
Flynn effect, 313, 313–314
fMRI. See Functional magnetic resonance
imaging
Food preferences and eating regulation, 122
“Forbidden” toys, 27
Foreclosure status, 447–448
Foreign-language speech perception, 227, 227
Formal operational stage of cognitive
development (Piaget), 135, 141–142,
143
Formula-feeding, 121
Fovea, 174
Fragile-X syndrome, 94, 251
Fraternal twins (dizygotic), 47, 100, 100–102,
104
sibling relationships in, 483–485
single-parent, 19
social competence of children and stress of,
548, 548
sociocultural context and, 469, 475
United States changes in, 485–498
age of childbearing, 485–489, 488
age of first marriage, 469, 485
birth rates outside marriage, 486, 488
child care, 500, 500
divorce and, 486–488, 489–496
economic arrangements, 485
lesbian and gay parents, 496–497
maternal employment, 498
stepparents, 494–496
See also Parenting styles and practices;
Parents and caregiving
Familism, 484
Family studies
behavior genetics and, 99–102, 101
intelligence and, 100, 100–102
HOME measure of, 310–312, 311
Fantasy play, 13, 282, 517
FAS. See Fetal alcohol syndrome
FASD. See Fetal alcohol spectrum disorder
Fast mapping, 236, 237
Fast Track intervention program, 588–589, 589
Fathers
feminine-stereotyped activities avoided by,
613
fetal hearing and voice of, 56
gay, 496–497
interactions with children of
cultural influences of, 482–483
after divorce, 492–493
mothers’ interactions compared to, 482–485
as noncustodial parent, 492–493
parental sensitivity and attachment of, 435
peer relationships influence of, 545–546
as stepparents compared to mothers, 495–
496
See also Families; Mothers; Parents and
caregiving
Fear, in children
development of, 390–391, 391
emergence of, 386, 387
individual differences and, 390–391
separation anxiety and, 391, 391
of strangers, 390
visual cliff and fear of heights, 196–197, 390,
391
Fearful distress, temperament dimension, 404,
405
Feelings and preferences, ethnic, 450, 450
Female reproductive system, 42–44, 43, 91
Feminine-stereotyped activities, gender-role
flexibility and, 613
Fetal alcohol effects (FAE), 62
Fetal alcohol spectrum disorder (FASD),
46, 62
External validity, 24–25, 25
Eyewitness testimony, public policy for
children giving, 4–5, 665–666
Faces
development of, 48–49, 49
infants attention and, 12, 187
attractiveness preference of, 177
preferences of, 176, 176–177, 177
visual scanning of, 175, 175, 176–177
racial preferences in recognition of, 177
Face-to-face communication, 529–530, 530
Facial expression
assessing regulation of, 420–421, 421
emotional expression and, 418
FAS causing deformities to, 62, 62
fetal, 50
FAE. See Fetal alcohol effects
Failure
conception, 43
resilience and, 21–22
to thrive, 120
Fallopian tube, 42, 43
False emotions, real emotions compared to,
419–421, 420, 421
False-belief problems, theory of mind and,
268–269, 270
Families, 467–507
adolescence and, 471
bidirectionality of parent–child interactions
in, 478, 478–479
child care success and characteristics of, 502
coercion of, 584–585
cultural influences taught by, 470
depression factors with, 396
dynamics of, 470–472
economic function of, 470
education valued by, 312
emotional development and, 410–414
parental socialization of children in,
411–414
parent–child relationship quality in,
410–411
environment and intelligence development
influences of, 310–312, 311
functions of, 470
homelessness and, 481
individual differences in members of, 20–21,
469, 477
IQ influence of, 100, 100
language development role of, 235
mothers’ and fathers’ interactions with
children in, 482–485
nature and nurture and, 469
parental socialization, influence on, 472–482
poverty influencing, 480, 480–482
research and children’s welfare and, 470
SES and communication of, 479
shared and nonshared environments of,
104–105, 312

S U B J E C T I N D E X n SI-11
biological influences on, 621–622
cultural influences on, 624–625
general intelligence, 619
mathematical skills and, 334, 620–621
overall academic achievement, 619
parental influences on, 622–623
peer influences on, 623–624
spatial ability and, 620, 620
teacher influences on, 623
verbal skills, 620
with dating violence, 631
display rules and, 421, 421
effect size and, 615, 615, 616
evaluating, 614–615, 615, 616
fetal vulnerability and, 44, 44
in friendship choice and selection, 524
in friendship functions, 519–520
in gender-typed behavior, 611–612, 613
height and, 119, 120
in interpersonal goals and communication,
626–628
in maternal employment impact, 499–
500
in mathematical anxiety, 334
in media representation, 605
moral judgment and, 561
older parents and, 488–489
in personality traits, 625–626
physical growth and, 119, 120
adolescence, 618–619
childhood and school-age children,
617–618
infants, 617
prenatal development, 617
play preferences and, 363
rejected children and, 548, 548
in risk taking, 625
self-regulation and, 625
with sexual harassment, 631
sexual identity and, 454
with stepparents, 495
weight and, 119, 120
Gender discrimination, 610
Gender dysphoria disorder, 598–599
Gender identity, 598–599, 600, 608
Gender schema filter, 602
Gender schema theory, 600–602, 601
Gender schemas, 601
Gender segregation, 609, 609–610
Gender stability, 600
Gender-essentialist statements, 604
Gender-role flexibility, 612, 613
Gender-role intensification, 612
Gender-typed behavior, 595
in adolescence, 612, 614
gender differences with, 611–612, 613
in middle childhood and school-age
children, 611–612
preschool age children and, 609–610
Gender-typing, 595, 604
Gender, sex compared to, 595
Gender constancy, 600, 608–609
Gender development, 593–635
activating influences and, 598
active child theme and, 595
assertion and affiliation in, 594, 611
biological theories on
biosocial theory, 597
evolutionary approaches to, 596–597
neuroscience and, 598–599
brain functioning and, 598–599
cognitive and motivational influences on,
599–606
cognitive development theory, 600
gender schema theory, 600–602, 601
social cognition theories, 603–604, 606
social identity theory, 602–603
cultural influences theories on
bioecological model of social development,
606–607
social role theory, 607
gender identity and, 598–599, 600, 608
hormones and, 598
individual differences and, 595
milestones in, 607–614
adolescence, 612, 614
infants and toddlers, 608
middle childhood and school-age children,
610–612
preschool years, 608–610
nature and nurture and, 595
observational learning and, 604
organizing influences and, 598
sociocultural context and, 595
theoretical approaches to, 595–607
transgender youth and, 599
Gender differences, 614–633
in activity level, 625
in adolescence
appearance concerns, 460, 460, 618
depression, 396, 396
physical growth, 618–619
in age of first marriage, 485
with aggression, 578–579, 579, 628–633
by age, 628
biological influences on, 629
cognitive and motivational influences on,
629–630
cultural influences on, 632–633
media influences on, 631–632
parental and other adult influences on, 630
peer influences on, 631
in antisocial behavior, 578–579, 579
bias in parental valuing of offspring and, 44
in birth rates, 44, 44
body image and, 618
brain structure and, 621
China’s one-child policy bias with, 468–469
in cognitive abilities and academic
achievement, 619–625
Freud’s conscience development theory,
566–567
Freud’s psychosexual development theory
anal stage in, 344
basic features of, 342
continuity/discontinuity in developmental
and, 15
current perspectives on, 347–348
developmental process in, 343–345
Electra complex in, 345
fixation in, 345
genital stage in, 345
latency period in, 345
Oedipus complex and, 344–345
oral stage in, 343
phallic stage in, 344
Friendship
active child theme in, 98
in adolescence, 516, 518, 518, 524–525
age and determination of, 515–517
age trends with self-disclosure and, 518, 518
aggression and disruptiveness from, 521
alcohol and drug abuse with, 521–523
buffering effect of, 518
children’s choice of, 523–525
cross-ethnic, 524
cultural influences on, 515, 522–523
definition of, 513
developmental changes in, 515, 515–517
functions of
gender differences in, 519–520
social competence and cognitive
development skills, 519
support and validation, 517–518
imaginary companions and, 273
infants’ possibilities for, 513–514
intimacy and, 515, 519–520
loneliness eased with, 518
preschoolers’ interactions with friends and
nonfriends, 514–515, 515
pretend play and, 514
psychological functioning and behavior
effects of
possible costs, 521–523
possible long-term benefits, 520–521
reciprocated best, 520–521
school-age children evaluating, 515, 515–517
See also Peer relationships
Frontal lobe, 108, 109
Functional magnetic resonance imaging
(fMRI), 110, 111, 117
Functionalist approach, to emotional
development, 386
g. See General intelligence
Gametes (germ cells), 42
Gangs, 528, 586, 586
Gatekeeping, parents and, 546–548
Gay parents, 496–497
Gay youth. See Sexual minority youth

SI-12 n S U B J E C T I N D E X
Guilt
development of, 392–393
empathy and, 393
in Erikson’s psychosocial development
theory, 346
recognition of, 418
shame compared to, 393
Habituation
definition of, 54
fetal, 54, 54
infant
learning and, 199, 199
speech perception and, 225–226
visual perception and, 174
mechanisms of developmental change and,
649
Half-siblings, 485
Hand plate, embryonic, 46, 46
Happiness, positive emotional development
and, 388–389
Harlow’s primate research on attachment,
427–428
Hawaii (Kauai), nature and nurture
longitudinal study, 2–3, 20
Head Start, 317–320, 503
Headplates, fetal, 67, 67
Healing, preschoolers understanding of,
276–277
Hearing. See Auditory development and
preferences
Hedonistic, self-focused orientation, in
prosocial behavior, 563
Height, as physical growth
adolescence and, 119, 119–120
age and continuity/discontinuity with, 16, 16
gender differences in, 119, 120
heritability and, 103
variability of, 120
Heights, fear of, 196–197
Helpless/entity orientation, 359
Hemispheres, cerebral, 109, 220
Hemophilia, 94
Heredity. See Genetics and heredity
Heritability
behavior genetics analysis of, 102–104
definition of, 102
environment and, 87, 104–105
estimates of, 103
IQ scores and, 103–104
nature of, 102–104
personality and, 105
schizophrenia and, 11, 11
See also Genetics and heredity
Heritable traits, 99
Herpes, 65
Heterozygous, 92, 94
Hidden objects
object permanence and, 131, 136, 144, 165,
206–207
child’s phenotype–child’s environment, 89,
97–98
parent’s genotype–child’s genotype, 89,
89–91
preschooler understanding of, 275–276
prosocial behavior contributions of, 572
random assortment and, 91
schizophrenia and, 11, 11
as self-esteem sources, 460, 460
sex determination in, 90, 90
teratogens and, 59
victimized children and, 542–543
Genie, imprisonment case, 220–221
Genital herpes, 65
Genital stage, in Freud’s psychosexual
development theory, 345
Genome, 11, 88
Genotype
active effects of, 310
definition of, 88
environmental interactions and, 93, 96,
96–97, 309–310
evocative effects of, 310
nature and nurture interaction with
child’s environment–child’s genotype, 89,
98–99
child’s genotype–child’s phenotype, 89,
91–93
parent’s genotype–child’s genotype, 89,
89–91
passive effects of, 310
Germ cells (gametes), 42
Gestures, 230, 248–249, 333–334
See also American Sign Language
Gesture–speech mismatches, 333
Girls compared to boys. See Gender
differences
Glial cells, 107–108
Goodness of fit, 409
Gossip, with peers, 519
Grammar
development and rules of, 243–244
gestures and, 248
parent’s role in child’s development of, 243
telegraphic speech and, 242
timing and development of, 639–640
Universal Grammar and, 248–249
Grasping reflex, 189, 189
Gratification, delay of, 384
Gray matter, brain, 106
Great Britain, research in, 6–7
Greece, child development and ancient, 7–9,
41–42
Growth curves, 119, 120
Guatemala, research in
infant sleeping arrangements of, 18–19
undernutrition and protein supplementation
in, 125
Guided participation, sociocultural theories of
cognitive development and, 155–156
Gene expression
developmental changes in, 91–92
dominance patterns in, 92–93
methylation and, 98
General intelligence (g), 299, 300–301, 301
Generativity, 217
Genes
anomalies, 94–95
definition of, 89
dominant, 92
environment and expression of, 17
human and non-human animals sharing
traits in, 88
recessive, 92
regulator, 91, 95
Genetic and environmental forces, 88–99
child’s environment–child’s genotype, 89,
98–99
child’s environment–child’s phenotype, 89,
93, 96–97
child’s genotype–child’s phenotype, 89,
91–93
child’s phenotype–child’s environment, 89,
97–98
parent’s genotype–child’s genotype, 89,
89–91
Genetic susceptibility, 59
Genetics and heredity
ADHD and, 370
age and influence of, 102
aggression and, 583
alcohol abuse and, 522–523
antisocial behavior and, 587–589
attachment and, 661
conception failure and, 43
depression and, 395
disorders transmitted by, 94–95
diversity and, 90–91
drug abuse and, 522–523
dyslexia and, 326
effortful attention and, 17
emotional regulation and, 402–403
epigenetics and, 11–12
gene expression and, 91–93, 98
genetic transmission process, 89
genome and, 11
of humans, 89–90
individual differences and, 20, 90–91, 659
intelligence development and, 100, 100–104,
308–320, 309
methylation and, 12
mutation and, 90, 94–95
nature and nurture interaction of
environment with
child’s environment–child’s genotype, 89,
98–99
child’s environment–child’s phenotype, 89,
93, 96–97
child’s genotype–child’s phenotype, 89,
91–93

S U B J E C T I N D E X n SI-13
parents and families influencing, 20–21, 469,
477
peer relationships and, 511, 522–523
philosophical history of, 8–9
predicting future on other dimensions of,
658–659
prenatal development and, 40, 59
in prosocial behavior, 571–576
in reading acquisition, 328
self-esteem and, 459, 658
social development theories and, 341, 342, 356
stability over time and, 658
teenage pregnancy and, 64
temperament and, 403
Individual selection, aggression and, 521
Industrial Revolution, child labor in, 9
Industry, Erikson’s psychosocial development
theory, 346
Infant Health and Development Project
(IHDP), 79
Infant mortality, 74–75, 75
Infant-directed speech (IDS), 223–224
Infantile amnesia, 344
Infants and toddlers, 40–41
actions, learning from, 164–165
active child theme and, 173
addition understanding of, 290, 290–291
cognitive development of, 205–211
future study of, 211
object knowledge, 206–207
physical knowledge, 207–208, 208
social knowledge, 208–211, 209, 210
support relations understood in, 207–208,
208
color perception of, 174–175, 264
competence of, 144
conception of self and, 440–441
conscience development of, 567–568
consonance preference of, 184–185
continuity/discontinuity and, 173
crying and
caregiver response to, 72–73
colic condition and, 74
evolution and evolutionary perspective on,
72–73
LBW babies and, 78
as newborn state of arousal, 70, 70, 72–74
soothing for, 73–74, 399
cultural influences in sleeping arrangements
of, 18, 18–19
developmental resilience and, 80
early causal reasoning of, 279–282
emotional expression of, 387–397
Erikson’s psychosocial development theory
and, 346
expanding world of, 192–198
faces and attention of, 12, 187
attractiveness preference with, 177
preferences with, 176, 176–177, 177
visual scanning of, 175, 175, 176–177
social identity theory and, 602–603
sociocultural context and formation of, 449
status categories of, 447–448
See also Self, conception of
Identity acceptance, in coming out, 456
Identity integration, in coming out, 456
Identity-achievement status, 448
Identity-diffusion status, 447–448
IDS. See Infant-directed speech
IHDP. See Infant Health and Development
Project
Illegal behavior, adolescents and, 554, 578–579
Illegal drugs, 63
See also Drug use/abuse
Illness, preschoolers understanding of, 276
Imaginary animals, 265–266, 266
Imaginary audience, egocentrism and, 444
Imaginary companions, 273
Imagination, of preschoolers, 282
Imitation, 136, 137, 202–204, 203, 209–211,
280, 280, 353–354, 604, 650
Immigrant children, victimization of, 542–543
Impossible/possible events, infant cognition
studies and, 207, 207
Imprinting, 363
In vitro fertilization (IVF), 76
Incentive motivation, 403
Income, IQ scores predicting, 307, 307–308
Incremental theory, 360
Incremental/mastery orientation, 359
Independent variable, 31
India, research in
social judgment domains in, 565
speech perception and, 226–227
Indirect aggression, 628
Indirect socializers, parents as, 472
Individual differences, 656–660
active child shaping, 21
attachment and, 427, 432–433, 436–437, 658
biology and behavior and, 86, 102
breadth of, at given time, 657–658
as child development theme, 10, 20–21
at conception, by sex, 44
continuity/discontinuity of, 645–646
determinants of, 659–660
dyslexia and, 95, 117, 326, 326
emotional development and, 385
in emotional regulation of, 402–410
experiences reflected in, 659–660
factors of, 20–21
fear and, 390–391
gender development and, 595
genetics causing, 20, 90–91, 659
imaginary companions and, 273
intelligence and, 298–299, 656–657, 657
IQ and, 306, 657, 657
language development and, 216
moral development and, 555
parental attachment status and, 432–433, 433
parenting style and, 472–473
space relative to external environment and,
285–286
Hierarchical categorization, 263, 263–265
Hindi, speech perception and, 226–227
Hinduism, 565
Hiroshima bombings, 117–118
Hispanic Americans
familism and, 484
illegal drugs and, 63
IQ scores of, 315
obesity and, 123
parental gatekeeping and, 547
parental warmth of, 476
Project Head Start and, 318
self-esteem and, 462–463
SES of, 19, 19, 80
SIDS and, 61
See also Mexican Americans
Historical context, identity formation and, 449
HIV. See Human immunodeficiency virus
Holophrastic period, 234
HOME (Home Observation for
Measurement of the Environment),
310–312, 311
Homelessness, parenting and, 481
Homosexual parents, 496–497
Homozygous, 92, 94
Hopi Indians, infant swaddling of, 73
Hormones
gender development and, 598
physical growth and, 120
prenatal development and, 47, 48, 59
Hostile attributional bias, 358, 372
5-HTTLPR gene, 588
Human immunodeficiency virus (HIV ), 65
Human nature, understanding of, 6–7
Huntington disease, 94
Hypotheses, 23–24, 25
Id, 343
Identical twins (monozygotic), 47, 98, 100,
100–102, 104
Identity
achievement, 446
adolescent formation of, 446–449
bicultural, 453
confusion, 446
crowds and, 527–528
Erikson’s psychosocial development theory,
346–347, 446–447
ethnic, 449–453
foreclosure, 447
gangs and, 528, 586, 586
gender, 598–599, 600, 608
historical context and formation of, 449
negative, 447
parental influences on formation of, 448–449
research on formation of, 447–448
sexual minority youth milestones with, 455
sexual orientation or, 453–458

SI-14 n S U B J E C T I N D E X
taste of
feeding and, 122
for soothing, 74
television and play quality of, 31
temperament of, 403–405, 405
theory of mind and, 267–271, 268
time experience of, 287–288
touch soothing, 73–74
violation-of-expectancy procedure and, 205,
206–207
visual acuity of, 174, 174–175
vocalizations of, 229–231, 230
See also Low birth weight babies; Visual
perception and vision
Inferiority, Erikson’s psychosocial development
theory, 346
Informal theories, of infants, 262–263
Information-processing theories, 144, 145–
155
addition and, 153
age and speed of processing, 152, 152–153
balance scale study with, 150
basic processes in, 150, 150–151, 651
central developmental issues in, 147–153,
155
child’s nature views of, 146–147
content knowledge and, 151–152, 652
definition of, 145
Dodge’s information-processing theory of
social problem solving, 357–358
educational application of, 154
encoding in, 150–151, 152
main questions addressed by, 131
mechanisms of developmental change and,
131, 651–652
memory and, 147–152
memory strategies and, 151
nature and nurture in, 147
overlapping-waves theory and, 152, 152–
153
problem solving and, 146–147, 152–153,
155, 357–358
selective attention and, 151
strategies for, 651–652
task analysis and, 146
Ingroup assimilation, 603
Ingroup bias, 603
Ingroup/outgroup gender schema, 601
Initiative, Erikson’s psychosocial development
theory, 346
Inner cell mass, 47
Insecure attachment, 431, 438
Insecure/avoidant attachment, 431, 437
Insecure/resistant attachment, 431
Instant messaging, 529–530, 530
Instrumental aggression, 578
Instrumental and exchange orientation,
Kohlberg’s stage of, 559
Instrumental conditioning (operant
conditioning), 201–202, 202, 350–352
milestones in, 162–163, 190, 190–191
perception and, 189–198
prereaching movements, 193
problem solving and, 162
reaching and, 192–194, 194, 208, 209
reflexes and, 189, 189–190, 192, 201
scale errors and, 196–197, 198
self-locomotion and, 194–198, 284
multiple-risk model for, 79–80, 80
naïve psychology of, 266–267
name recognition of, 229
nature and nurture and, 173, 639
negative birth outcomes and, 74–81
negative emotions of, 389–392
newborns
learning during sleep and, 71
napping and, 71
quiet-alert state of, 70, 70
states of arousal, 70, 70–74
object categorization by, 263–264
object segregation and, 179, 179–180
parental attachment status with, 432–433,
433
pattern perception of, 175, 178, 201
peer groups of, 525
peer relationships of, 513–515
perception of
auditory, 182, 184–185
intermodal, 186–188, 200
overview of, 172–173
smell, 186
taste, 122, 186
touch, 186
visual, 173–182
Piaget’s insight into, 135–138, 144
picture perception and, 183
poverty and, 19, 80
premature, 76, 77, 78, 166
problem solving of, 280–281, 281
rapid change with, 172
reactions from other people elicited by,
644
response to distress of, 74
secure attachment and, 437–439
self-initiated activity of, 642–643
SIDS and, 60, 61, 195
sitting ability of, 193
sleep and, 70–72, 71
sleep–wake cycles of, 72
small for gestational age, 76
social integration of, 68
social referencing of, 197, 417
social smiles of, 388
sociocultural context and, 173
spatial representations of, 283–285
states of arousal with
crying, newborn, 70, 70, 72–74
sleep and, 70–72, 71
swaddling, 73
sweet taste preference of, 74, 122
Infants and toddlers (cont.)
failure to thrive and, 120
feeding, 121, 121–122
friendship possibilities for, 513–514
gender development milestones with,
608
gender differences in physical growth with,
617
general magnitude representations of,
292–293, 293
habituation of
learning and, 199, 199
speech perception and, 225–226
visual, 174
IDS and, 223–224
infant mortality and, 74–75, 75
informal theories of, 262–263
intersubjectivity and, 159, 231
IQ testing and, 306
language acquisition of, 224–246
conversational skills in, 244–246
first words in, 231–242, 234
preparation for speech production in,
229–231
prerequisites for, 246
putting words together in, 242–244
speech perception in, 224–228
technology and, 240–241
word segmentation in, 228–229
LBW and, 60, 65, 76–79, 365–366
learning and, 172–173, 198–205
classical conditioning, 201
habituation, 199, 199
instrumental, operant conditioning, 201–
202, 202, 350–352
observational learning and imitation, 136,
137, 202–204, 203, 209–211, 280, 280,
353–354, 604, 650
perceptual learning, 199–200
rational learning, 204–205, 650
during sleep, 71
statistical learning, 200–201, 650
living things distinguished from nonliving
things by, 274, 274–275
massaging, 79, 79
maternal employment influence on, 498–
500, 500
mathematics and, 290–291
mechanisms of developmental change and,
173
mother’s bond with, 12
as motivators of development, 163–164
motor development of
brain maturation and, 191
crawling and, 190, 194–197
cultural influences on, 190–191
current views on, 191, 195
dynamic-systems theories and, 192
mechanisms of developmental change and,
196–197

S U B J E C T I N D E X n SI-15
normal distribution of, 304, 304
poverty and, 314, 314–315, 317
Project Head Start and, 318–319
risk factors related to, 315–317, 316
SES and, 103, 307, 307–308, 314, 314–315
stability shown in, 645
standard deviation and, 304–305
testing
Binet-Simon Intelligence Test, 298
infants and, 306
Stanford-Binet intelligence test, 302
WISC, 302, 303
See also Intelligence
Irritable distress, temperament dimension,
404, 405
Isolation, obesity causing, 124
Isotretinoin (Accutane), 60
IVF. See In vitro fertilization
Ivory Coast, Africa, 41
Japan, research in
academic achievement and employment in,
314, 314–315
attachment in, 434
emotional development and, 414–415
emotional expression in, 654
environmental influences on prenatal
development in, 56–57, 117–118
labeling objects in, 234
peer relationship experience in, 522–523
prosocial behavior in, 573
self-conscious emotions and, 393
Jigsaw approach, for education, 161
Joint attention, 159, 159, 231
Joint custody, 493
Juvenile delinquency, 581
Karyotype, 90
Kauai, nature and nurture longitudinal study,
2–3, 20
Kenya, research studies in
father and mother interactions with children
in, 483
motor development milestones and, 191
peer relationship experience in, 522–523
United States newborn sleep–wake cycles
compared to, 72
Kismet (robot), 340–341, 348, 355, 361, 379
Kleinfelter syndrome, 94
Knowledge, ethnic, 450, 450
Kohlberg’s theories
of cognitive development, 600
of moral judgment, 15, 558–561
critique of, 560–561
dilemmas in, 558–559
stages in, 559, 559–560, 560
Korea, research in, 234
Labeling objects, 233–234, 241
Lake Michigan, 63
Intermodal perception, of infants, 186–188,
200
Internal validity, 24, 25
Internal working model of attachment, 429,
437
Internalization, superego and, 344
Internet, 373, 376, 529–530
Interneurons, 106
Interpersonal goals, gender differences and,
626–628
Interpersonal intelligence (Gardner), 321
Interposition, pictorial cues, 181
Interrater reliability, 24, 25
Intersubjectivity, 159, 231
Interventions, for at-risk children
anti-bullying, 589
child maltreatment prevention programs,
373
Fast Track program, 588–589, 589
parental sensitivity and attachment and,
436
programs for poor children, 317–320
prosocial behavior promoted by, 576
timing for, 662–663
Interviews, for data gathering, 25–26, 28
Intimacy, friendship and, 515, 519–520
Intrapersonal intelligence (Gardner), 321
Inuit (Alaska), sex selection of children by, 44
Invariant sequence, in Piaget’s cognitive
development theory, 134
IQ (intelligence quotient)
academic achievement predictor of, 306, 307,
307–308
of African Americans
group differences with, 315
heritability of, 104
poverty intervention programs boosting,
317
age and comparisons of, 305, 313, 313
breastfeeding and, 121
continuity of, 305
definition of, 304
emotional intelligence and, 385
environment and, 305
of European Americans
group differences with, 315
heritability of, 75
family influence on, 100, 100
Flynn effect and, 313–314, 314
heritability and, 103–104
of Hispanic Americans, 315
HOME measure and, 310–312, 311
important outcomes predicted by, 307,
307–308
income and earnings predicted by, 307,
307–308
individual differences and, 306, 657, 657
mathematics disabilities and, 335
mean and, 304
of Native Americans, 315
Intelligence, 297–337
active child theme and, 299, 310
age-related changes in, 298, 309, 309
alternative perspectives on, 320–322
as basic abilities, 299–300
child development studies applied to, 21
continuity/discontinuity and, 299, 305
crystallized, 300
defining, 299–301
emotional, 384–385
entity theory of, 359
environment and development of, 308–320
family influences on, 310–312, 311
genotype interactions with, 93, 96, 96–97,
309–310
school influence on, 312–313, 313
shared and nonshared family environments,
312
societal influence on, 313–320
family studies of, 100, 100–102
HOME measure of, 310–312, 311
fluid, 299–300
gender differences in general, 619
general, 299, 300–301, 301
genetics and development of, 100, 100–104,
308–320, 309
incremental theory of, 360
individual differences and, 298–299, 656–
657, 657
LBW babies outcomes with, 79
measuring, 301–306
mechanisms of developmental change and,
299
multiple intelligences theory of, 320–321,
321
nature and nurture and, 299
as numerous processes, 300
primary mental abilities and, 300
race, ethnicity and development of, 315
research and children’s welfare and, 299
risk factors in development of, 315–317,
316
Romanian orphan adoption outcomes and, 7
sensorimotor stage of cognitive development
and, 135
as single trait, 299
societal influence on, 313–320
sociocultural context and, 299
testing, 298, 301–306
theory of successful, 321–322
three-stratum theory of, 300–301, 301
See also IQ
Intelligence quotient. See IQ
Intention
first words and, 237–238
observational learning, imitation and, 203,
203, 209–211
preschool-age children and, 237–238
Interest filter, 602
Intermittent reinforcement, 351

SI-16 n S U B J E C T I N D E X
Low birth weight babies (LBW babies),
365–366
African Americans and, 76
child maltreatment and, 78
cigarette smoking by mother and, 60
crying and, 78
definition of, 76
intelligence outcomes of, 79
intervention programs for, 77, 79
long-term outcomes of, 76–77, 77
malnutrition and, 65
parenting challenges with, 78
Macrosystem, in bioecological model, 367,
368
Magic, belief in, 282
Magnitude, infants representations of general,
292–293, 293
Male-pattern baldness, 94
Malnutrition
cognitive development and, 124–125, 125
LBW babies and, 65
measurement of, 23–24
poverty, SES and, 65, 124–125
prenatal development and, 64–65
Romanian adoption studies and, 6–7, 116,
427, 640
See also Nutrition
Maltreatment. See Child maltreatment
Manual babbling, 230, 230
MAOA gene, 97
Marijuana, 63
Marriage
age of first, 469, 485
birth rates outside, 486, 488
children born outside, 469
ongoing conflict in, 494
See also Divorce; Families
Masculine-stereotyped activities, gender-role
flexibility and, 613
Massages, for infants, 79, 79
Mastery/incremental orientation, 359
Maternal emotional state, 65–66
Maternal employment. See Employment,
maternal
Maternity leave, 664–665
Mathematical equality, 333
Mathematics
acquisition of skills for, 330–335
anxiety and, 334
arithmetic, 330–334
counting, 154, 291, 291–292, 292, 331
disabilities, 335
gender differences and, 620–621
infants and, 290–291
See also Addition
Mayans (Guatemala), infant sleeping
arrangements of, 18–19
Mean IQ, 304
Measles, 3-day, 65
Late talkers, 251
Latency period, in Freud’s psychosexual
development theory, 345
Latinos. See Hispanic Americans
LBW babies. See Low birth weight babies
Learning
arithmetic strategies for, 330–331, 330–331
effortful attention and, 17
failure and, 21–22
fetal, 40, 46, 54–56, 57
first words, 236–241
general mechanisms of, 206
goals, 359
infants and, 172–173, 198–205
classical conditioning, 201
habituation, 199, 199
instrumental, operant conditioning, 201–
202, 202, 350–352
observational learning and imitation, 136,
137, 202–204, 203, 209–211, 280, 280,
353–354, 604, 650
perceptual learning, 199–200
rational learning, 204–205, 650
during sleep, 71
statistical learning, 200–201, 650
linguistic context and, 238–239, 239
perceptual, 199–200
prenatal, 54–56, 55
as social, 353
specialized mechanisms of, 206
See also Cognitive development; Education;
Preschool and preschool-age children;
School and school-age children
Learning disabilities
ADHD, 94, 370–371, 580, 589
dyslexia, 95, 117, 326, 326
intervention timing for, 662–663
Learning theories, 348–356
central developmental issues and, 349
current perspectives on, 355
imitation, 136, 137, 202–204, 203, 209–211,
280, 280, 353–354, 604, 650
Skinner’s operant conditioning, 350–352
social learning theory, 352–355, 650–651
view of child’s nature, 349
Watson’s behaviorist theory, 349–350
Legal drugs, 59–60, 62–63
Lesbian parents, 496–497
Lesbian youth. See Sexual minority youth
Linguistic context, 238–239, 239
Linguistic intelligence (Gardner), 321
Living things, nonliving things distinguished
from, 274, 274–275
Lobes, of cerebral cortex, 108, 108–109
Localization, auditory, 182
Logical-mathematical intelligence (Gardner),
321
Loneliness, friendship easing, 518
Longitudinal designs, 33, 35
Long-term memory, 148
Language development, 216–257
acquisition process of, 224–246
conversational skills in, 244–246
first words in, 231–242, 234
preparation for speech production in,
229–231
prerequisites for, 246
putting words together in, 242–244
speech perception in, 224–228
technology and, 240–241
word segmentation in, 228–229
active child theme and, 12, 216
age and furthered, 246
ASD and, 251
ASL and, 115, 218, 221, 227, 230
babbling and, 230, 230–231
bilingualism and, 222
brain and, 219–221
cerebral cortex and, 220
child care and, 503–504
components of, 217–218
comprehension and, 217
connectionism and, 252
critical period for, 220–221, 221
with deaf children, 230, 248–249, 251
debates ongoing in, 250–252
disorders in, 251
domain-specific and domain-general, 250–
251, 652–653
environment and, 221, 223–224
family and school context’s role in, 235
fast mapping and, 236, 237
grammar and
parent’s role in child’s development of, 243
rules of, 243–244
telegraphic speech and, 242
IDS and, 223–224
individual differences and, 216
milestones in, 236
mutual exclusivity assumption in, 237
nativist views of Chomsky on, 247–249
nature and nurture and, 216, 250
nonlinguistic symbols and, 252–256
NSL and, 248–249
phonological development and, 217
pragmatic cues in, 237, 238
pragmatic development and, 218, 237, 238
prenatal development and, 56
reference problems in, 231
requirements for, 218–224
semantic development and, 217
SES and, 235
sociocultural context and, 216, 230–231
syntactic bootstrapping and, 239–241, 240
syntactic development and, 218
theoretical issues in, 246–252
See also Auditory development and
preferences; Speech
Language disorders, 251
Language production, 217

S U B J E C T I N D E X n SI-17
prosocial behavior in, 555, 562–563, 563,
568–577
research and children’s welfare and, 555
social conventional judgments and, 564–
566
sociocultural context and, 555, 572–576
See also Antisocial behavior; Prosocial
behavior
Moral judgment
cultural influences and, 561
definition of, 563–564
determining, 555
gender differences and, 561
Kohlberg’s theory on, 15, 558–561
critique of, 560–561
dilemmas in, 558–559
stages in, 559, 559–560, 560
Piaget’s theory of, 555–558
autonomous morality stage in, 557
evaluation of, 557–558
morality of constraint stage of, 556
transitional period in, 556–557
prosocial, 562–563, 563
social judgment domains, 563–566
The Moral Judgment of the Child (Piaget), 555
Moral relativism, 557
Morality of constraint, Piaget’s stage of, 556
Moratorium status, 447–448
Morning sickness, 57
Morphemes, 217
Mothers
breastfeeding and, 121, 121
depressed, 30, 436
failure to thrive babies and, 120
fetal hearing and voice of, 54–55
gender-typing and, 604
guided participation used by, 155–156
imprinting and, 363
infant’s bond with, 12
interactions with children of
after divorce, 493
father interactions compared to, 482–485
LBW babies and cigarette smoking of, 60
lesbian, 496–497
as noncustodial parents, 493
parental sensitivity and attachment of,
435–437
prenatal development factors with, 64–66
separation anxiety and, 391, 391, 429
single-parent families and, 19
as stepparents compared to fathers, 495–
496
See also Childbirth; Families; Fathers; Parents
and caregiving; Pregnancy
Motivation
achievement, 359–361
incentive, 403
Motivational theories, of gender development,
599–606
Motivators of development, 163–164
music perception and, 184
rehearsal and, 151
temporal lobe and, 108
working, 147–148
Men Are from Mars, Women Are from Venus
(Gray), 626
Menarche, 618
Mendelian inheritance, 92, 92
Mental model, 325
Mental operations, sensorimotor stage of
cognitive development and, 135–138
Mercury, prenatal impact of, 57
Mesosystem, in bioecological model, 367,
368
Meta-analysis, 615
Metacognition, 652
Metacognitive knowledge, writing and,
329–330
Metalinguistic knowledge, 218
Methylation, 12, 98
Mexican Americans
familism and, 484
majority and traditional values conflicts with,
451
parental gatekeeping and, 547
peer pressure susceptibility of, 586
prosocial tendencies of, 573
See also Hispanic Americans
Microgenetic designs, 33–34, 35
Micronesia, research in, 224
Microsystem, Bioecological model, 367,
367–368
Midwives, 68
Migration, cellular, 45
Milk, breast, 121
Minamata disease, 57, 63
Minnesota Study of Twins Reared Apart, 101
Minority groups. See specific groups
Mirror neuron system, 204
Miscarriages, 56
Mistrust, Erikson’s psychosocial development
theory, 346
Mitosis, 45
MMR vaccine, 95
Modularity hypothesis, 250
Monocular depth cues, 181–182, 182
Monozygotic twins. See Identical twins
Moral development, 553–591
active child theme and, 555
altruistic motives and, 569
antisocial behavior and, 103, 554, 573,
577–590
conscience development and, 555, 566–568,
659–660
continuity/discontinuity and, 555, 561
individual differences and, 555
mechanisms of developmental change and,
555
nature and nurture and, 555, 571–572
personal judgments and, 564–566
Measurement, importance of appropriate,
23–25, 25
Mechanisms of developmental change
biology and behavior and, 86, 648–649
in brain, 648–649
cognitive development and, 144, 651–653
conceptual development and, 260
conditioning and, 649–650
domain-specific/domain-general language
development and, 652–653
dynamic-systems theories and, 166–167
explained, 16–17
habituation and, 649
infants and, 173
information-processing theories and, 131,
651–652
intelligence and, 299
moral development and, 555
motor development and, 196–197
Piaget’s cognitive development theory and,
648
questions about, 10
rational learning, 650
social development theories and, 349
social learning and, 650–651
statistical learning and, 650
working together, 653
Media, influence on children, 372–376
academic achievement effects of, 375
aggression gender differences and, 631–632
exposure concerns with, 374–376
gender representation in, 605
increased usage and, 373–374
mobile screens and, 372–374
physical inactivity and, 375
pornography concerns and, 376
SES inequities and, 375–376
violence and, 374–375
See also Television watching
Medications. See Drug use/abuse
Meiosis, 42
Melody, music perception and, 185
Memory
addition and, 152
autobiographical, 160
brain control of, 148, 148
court testimony by children and, 5
development
basic processes of, 150, 150–151
content knowledge and, 151–152, 652
explanations of, 149–152
strategies of, 151
dynamic-systems theories and, 164–165
emotional expression triggered by, 419
executive functions and, 148, 148–149
fetal, 55
information-processing theories and,
147–152
long-term, 148
mathematics anxiety and, 334

SI-18 n S U B J E C T I N D E X
Needs-based orientation, in prosocial behavior,
563
Negative emotions
adolescence increase of, 394
anger and sadness development and, 391–
392
cognitive strategies to control, 400
environmental influences on, 394–395
fear and distress development and, 390–391,
391
infant development of, 389–392
parent assistance for, 3–4
parental reaction to child’s, 412–413
positive emotions from same source as, 419
separation anxiety and, 391, 391
social competence and, 412
Negative identity, 447
Neglect, parental, 473, 473, 474–475
Neglected children, 533, 537
Neighborhood, as self-esteem source, 461
Nepal, research in, 415, 421
Netherlands, research in
crowd identification in, 527–528
World War II prenatal nutrition study in, 65
“Neural Darwinism,” 114
Neural tube, 47, 47
Neurofibromatosis, 94
Neurogenesis, 109–112, 648
Neuroimaging, 110–111, 111
See also specific types
Neurons
definition of, 106
development of, 109–112, 648
mirror, 204
structure and function of, 106–107, 107
Neurotransmitters, 17, 107
New York Longitudinal Study, 403–404
Newborns. See Infants and toddlers
Ngandu, emotional development, 414
Nicaraguan Sign Language (NSL), 248–249
NICHD. See National Institute of Child
Health and Development
NIRS. See Near-infrared spectroscopy
Noncustodial parents, 492–493, 496
Nonhuman animals
human development and, 46
humans sharing gene traits with, 88
Nonlinguistic symbols, 252–256
Non-REM sleep, 70–71, 71
Norm of reaction, 93, 96
Normal distribution, of IQ scores, 304, 304
Nouns, in early vocabulary, 233
Novelty preference, dynamic-systems theories
and, 167
NSL. See Nicaraguan Sign Language
Nthlakapmx, speech perception and, 226–227
Numbers
academic achievement and early knowledge
of, 154, 306
conceptual development and, 288–293
biological knowledge acquisition, 277
causality, 279
knowledge of people and self, 266
number, 288–289
space, 283
theory of mind, 269–270
of language development by Chomsky,
247–249
of object perception, 178–179
Natural selection. See Evolution and
evolutionary perspective
Naturalistic intelligence (Gardner), 321
Naturalistic observation, 26–27, 28
Nature, defined, 10–11
Nature and nurture, as developmental theme,
11
attachment and, 427
bidirectional interaction of, 12
biology and behavior and, 86, 87–105
brain plasticity and, 115
child development shaped by, 10–12
complexity of, 641
conceptual development and, 260–261
emotional development and, 385
environment and heritability, 87–88
epigenetics and, 640–641
families and, 469
gender development and, 595
genetic and environmental forces in
child’s environment–child’s genotype, 89,
98–99
child’s environment–child’s phenotype, 89,
93, 96–97
child’s genotype–child’s phenotype, 89,
91–93
child’s phenotype–child’s environment, 89,
97–98
parent’s genotype–child’s genotype, 89,
89–91
Hawaii study on, 2–3, 20
heritability and, 102–104
infants and, 173, 639
information-processing theories and, 147
intelligence and, 299
language development and, 216, 250
moral development and, 555, 571–572
peer relationships and, 511–512
in Piaget’s cognitive development theory,
133
prenatal development and, 40, 638–639
questions about, 10
schizophrenia and, 11, 640
self-esteem and, 459
social development theories and, 341, 342,
362
temperament and, 403
timing as crucial in, 7
timing matters and, 439–440
Navajo Indians, infant swaddling of, 73
Near-infrared spectroscopy (NIRS), 110–111
Motor development
brain maturation and, 191
crawling and, 190, 194–197
cultural influences on, 190–191
current views on, 191, 195
dynamic-systems theories and, 192
mechanisms of developmental change and,
196–197
milestones in, 162–163, 190, 190–191
perception and, 188–198
prereaching movements and, 193
problem solving and, 162
reaching and, 192–194, 194, 208, 209
reflexes and, 189, 189–190, 192, 201
scale errors and, 196–197, 198
self-locomotion and, 194–198, 284
visual development and, 193
Motor neurons, 106
Movement
common, 179–180
of fetus, 49–50, 51–52
infant visual preference for, 175
object segregation in infant vision and, 179,
179–180
Multifactorial traits, 99
Multiple intelligences theory, 320–321, 321
Multiple sclerosis, 107–108
Multiple selves, of adolescents, 443–446, 445
Multiple-risk model, for infants, 79–80, 80
Multiplication, strategy choices for, 331, 331
Music perception, 184–185
Musical intelligence (Gardner), 321
Mutation, 90, 94–95
Mutual exclusivity assumption, in language
development, 237
Mutual interpersonal expectations,
relationships, and interpersonal
conformity, Kohlberg’s stage of, 559
Myelin sheath, 107–108, 112
Myelination, 112, 151, 648
Nagasaki bombings, 117–118
Naïve psychology, infants, 266–267
Name recognition, of infants, 229
Napping, newborns and, 71
Narratives, scaffolding, 245
National Association of Young Children, 505
National Institute of Child Health and
Development (NICHD), 501–504
Native Americans
infant swaddling techniques of, 73
IQ scores of, 315
negative peer group influence and, 528, 531
self-conscious emotions and, 393
sex selection of children by, 44
SIDS and, 61
speech perception and, 226–227
Nativist views
on cognitive development, 205–206
on conceptual development, 260–261

S U B J E C T I N D E X n SI-19
age trends with self-disclosure and, 518, 518
aggression and conflict with, 585
aggression gender differences influence of,
630
attachment relationship of child and,
427–439
attachment status of, 432–433, 433
behaviorist theory responsibility placed on,
350
bias in valuing offspring by gender, 44
bidirectionality of parent–child interactions,
478, 478–479
biological knowledge acquisition aided by,
277
child development research for, 3–4
children’s negative emotions reaction of,
412–413
child’s environment contributions of, 97,
661
conception of self contributions from, 441
consistently responsive caregiving, 435
cultural influences on beliefs and behaviors
of, 421, 475–476
custody issues for, 493
as direct instructors, 472
divorce and conflict between, 490
eating influence of, 122
emotional development, relationship of child
and, 410–411
emotional expression of, 411–412
emotions discussed by, 413–414
feminine-stereotyped activities avoided by,
613
gender differences in academic achievement
and, 622–623
gender-typing and, 604
grammar development of child and role of,
243
guided participation used by, 155–156
identity formation influence of, 448–449
as indirect socializers, 472
individual differences influenced by, 20–21,
469, 477
infant crying and response of, 72–73
for LBW babies, 78
lesbian and gay parents, 496–497
mathematics anxiety and, 334
narrative scaffolding and, 245
naturalistic observation of negative behavior
and, 26–27
negative emotions assistance for, 3–4
noncustodial, 492–493, 496
older, 488–489
peer relationships role of, 544–549
attachment and social competence with,
544–545
family stress and children’s social
competence, 548, 548
fathers’ influence on, 545–546
gatekeeping and coaching and, 546–548
Older parents, 488–489
One-child policy, in China, 468–469
One-one correspondence, counting and, 291
Only children, 468–469
Operant conditioning (instrumental
conditioning), 201–202, 202, 350–352
Opportunity structure, 606
Oppositional defiant disorder (ODD), 580
Optical expansion, depth perception and,
180–181
Oral stage, in Freud’s psychosexual
development theory, 343
Order irrelevance, counting and, 291
ORE. See Other race effect
Organizing influences, gender development
and, 598
Orphan studies
Freud, Anna’s, concentration camp survivor
study, 510–511
Romanian orphan adoption outcomes, 6–7,
116, 427, 640
of Spitz, 426
on World War II children, 426
Other race effect (ORE), 177
Outliers (Gladwell), 307
Overextension, of first words, 234, 234–235
Overlapping-waves theory, 152, 152–153
Overregularization, 243
Own-gender schema, 601
Papua New Guinea, research in, 224, 562
Paraguay, motor development milestones and,
190–191
Parental punitiveness, discipline and, 583–584
Parental sensitivity, attachment and, 435–437
Parental-investment theory, 365
Parenting styles and practices
active child shaping, 477
authoritarian, 473, 473, 474, 475–476, 479
authoritative, 473, 473–474, 476, 479, 575
child influencing, 475
attractiveness of, 477
temperaments and behaviors of, 477–479,
478
cultural influences on, 475–476
definition of, 472
differential susceptibility and, 478
discipline and, 472–476, 575–576
individual differences with, 472–473
permissive, 473, 473, 474
race and, 475–476
rejecting-neglecting, 473, 473, 474–475
SES influencing, 475–476, 479–482
economic stress and, 480, 480, 482
homelessness and, 481
warmth in, 473, 476, 575–576
Parents and caregiving
ADHD linked to, 370
adolescents as, 64, 486–487
adolescents’ relationship with, 471
conservation of, 140
counting, 291, 291–292, 292, 331
empiricist views on, 289
infant’s addition understanding, 290,
290–291
nativist views on, 288–289
numerical equality and, 289
for play, 154
play with, 154, 306
space and time relations with, 292–293
See also Arithmetic; Mathematics
Numerical equality, 289
Numerical magnitude representations, 332,
332–333, 333
Nurture, defined, 11
See also Nature and nurture, as developmental
theme
Nutrition
healthy eating habits and, 124
infant feeding and, 121, 121–122
obesity and, 122–124, 123
physical growth and behavior with, 121–125
prenatal development and, 64–65
undernutrition, 124–125, 125
See also Eating; Malnutrition
Obesity, 122–124, 123
Object knowledge, 206–207
Object substitution, 271
Objects
categorization of, 261–266
category hierarchies in, 263, 263–265
causality and, 265–266, 266
beyond infancy, 264–266
by infants, 263–264
infant visual perception of, 178–180
labeling, 233–234, 241
Piaget’s cognitive development theory and
permanence of, 131, 136, 144, 165,
206–207
segregation of, 179, 179–180
space relative to external environment and
hidden, 285–286
Obliging statements, 627, 627
Observation
naturalistic, 26–27, 28
structured, 27–28, 28
Observational learning, 136, 137, 353–354
gender development and, 604
infants and, 202–204, 203
intention and, 203, 203, 209–211
Occipital lobe, 108, 108
Occupation. See Employment
Occupational hazards, for prenatal
development, 63–64, 64
ODD. See Oppositional defiant disorder
Oedipus complex, in Freud’s psychosexual
development theory, 344–345
Offspring survival, parental-investment theory
and, 365

SI-20 n S U B J E C T I N D E X
overview of, 172–173
smell, 186
taste, 122, 186
touch, 186
visual, 173–182
learning and, 198–205
motor development and, 188–198
music, 184–185
object segregation and, 179, 179–180
of objects, 178–180
of patterns, 175, 178, 201
pictures and, 183
scale errors and, 196–197, 198
self-esteem test with self-, 459
speech, 224–228
subitizing and, 290–291
See also Visual perception and vision
Perceptual categorization, 264
Perceptual constancy, 178
Perceptual learning, 199–200
Performance goals, 359
Performance problems, of rejected children,
538
Permissive parenting style, 473, 473, 474
Personal fable, 443–444
Personal judgments, 564–566
Personality
gender differences in, 625–626
heritability and, 105
See also specific traits
Peru, infant swaddling in, 73
PET. See Positron emission tomography
Phallic stage, in Freud’s psychosexual
development theory, 344
Phenotype
definition of, 88
environmental interactions
child’s environment–child’s phenotype, 89,
93, 96–97
child’s genotype–child’s phenotype, 89,
91–93
child’s phenotype–child’s environment, 89,
97–98
Phenylalanine, 96
Phenylketonuria (PKU), 93, 96
Philosophers’ views of child development, 8–9
Phonemes, 217, 225–226
Phonemic awareness, 322, 323–324
Phonological development, language and, 217
Phonological recoding skills, 322, 324
Phylogenetic continuity, 46, 47
Physical growth
continuity/discontinuity in development and,
16, 16
environment variables with, 120
gender differences and, 119, 120
adolescence, 618–619
childhood and school-age children, 617
infants, 617
prenatal development, 617
individual differences and, 511, 522–523
infants and, 513–515
nature and nurture and, 511–512
parental role in, 544–549
attachment and social competence with,
544–545
family stress and children’s social
competence, 548, 548
fathers’ influence on, 545–546
gatekeeping and coaching and, 546–548
parental beliefs and, 546
quality of ongoing parent–child
interactions and, 545–546
peer, definition of, 512
peer-nominated aggression by age, 579, 579
pressure from, 521–522, 586
rejected children, fostering acceptance of
peers, 538
research and children’s welfare and, 512
romance in, 531–532
secure attachment and, 437–438
as self-esteem sources, 460, 460–461
shared emotional expression in, 524–525
siblings divergent experiences and, 105
social media, cyberspace and, 529–530
sociocultural context and, 511
special nature of, 512–513
victimization and, 397
See also Friendship
Peer status, 532–544
attractiveness and, 533, 534
cross-cultural similarities and differences
with, 539–540
relational aggression and, 535
as risk predictor
academic performance and, 540–541, 541
adjustment problems and, 541, 541–543,
542
paths to risk, 543
victimized children and, 542–543
sociometric measurement of
categories of, 533
characteristics of, 533, 533–539
controversial children, 533, 537, 539
neglected children, 533, 537
rejected children, 533, 535–537, 538, 541,
541–543, 542, 548, 548
stability of, 539
Pendulum problem (Piaget), 141, 141
Penis envy, 344
Perceived self-efficacy, 354–355
Perception
age and narrowing of, 185, 187–188
categorical, 224–226, 225, 226
cognition and, 205–211
definition of, 173
depth, 180–182, 181, 182
of infants
auditory, 182, 184–185
intermodal, 186–188, 200
Parents and caregiving (cont.)
parental beliefs and, 546
quality of ongoing parent–child
interactions and, 545–546
psychological control of children by, 474
research and children’s welfare implications
for, 660–661
romantic relationships of adolescents
modeled after, 532
secure attachment formed by, 661
as secure base, 428
sensitivity of, 435–437
sexual identity or orientation of, 496–497
siblings’ relationships influenced by
relationship of, 485
as social managers, 472
socialization of
of children’s emotional responding,
411–414
family influence of, 472–482
of prosocial behavior, 572–576
styles and practices of, 472–482
structured observation and, 27–28
sympathy expressed as strategy for, 3–4
warmth from, 473, 476, 575–576
See also Discipline; Families; Fathers;
Mothers
Parietal lobe, 108, 108–109
Passive effects, of genotype, 310
PATHS (Promoting Alternative Thinking
Strategies), 538
Pattern perception, 175, 178, 201
PCBs. See Polychlorinated biphenyls
Peer pressure, 521–522, 586
Peer relationships, 509–551
active child theme and, 512
aggression influenced by, 586–587, 631
authenticity of, 461
bullying and, 529–530, 589
conception of self and, 443–446
continuity/discontinuity and, 512
cooperation in, 512, 514
cross-gender, 611
cultural influences on, 522–523
in Freud, Anna’s, concentration camp
survivor study, 510–511
gender differences in academic achievement
and, 623–624
gender-segregated, 609–610
gossip and, 519
in groups
cliques and social networks in adolescence,
526–528
cliques and social networks in middle
childhood, 526
crowds and, 527–528
cultural negative influences on, 528, 531
gangs and, 528, 586, 586
status in, 532–544, 533
of young children, 525

S U B J E C T I N D E X n SI-21
environmental hazards with, 59
families influenced by, 480, 480–482
health problems and, 19
homelessness and, 481
infants and, 19, 80
intelligence development influenced by, 314,
314–315
IQ and, 314, 314–315, 317
malnutrition and, 65, 124–125
overcoming, 20
programs for helping poor children and,
317–320
by race, 19, 19
resilience and, 80
single-parent families and, 19
stress and, 548, 586
See also Socioeconomic status
Power-assertive strategies, 629
Practical abilities, successful intelligence and,
321–322
Practices, sociocultural context and, 653–655
Pragmatic cues, in language development, 237,
238
Pragmatic development
communication and, 245–246
language and, 218, 237, 238
Preattachment, 429
Preconventional moral reasoning, Kohlberg’s
stage of, 559, 559–560
Preferential-looking technique, 174
Preformationism concept, 42, 42
Pregnancy
adolescent, 64, 486–487
age at, 2–3, 64, 485–489, 488
ensuring healthy, 660
See also Childbirth; Fetus; Prenatal
development
Premature infants, 76, 77, 78, 166, 365–366
See also Low birth weight babies
Prenatal development
active child theme and, 40
age and, 64
alcohol abuse and, 46, 60, 62, 62–63
auditory senses and, 53–54, 55–56, 64
behavioral cycles in, 52
Beng people and, 41
bilingualism and, 222
cigarette smoke and, 60, 61
conception and, 42–44, 45
continuity/discontinuity and, 40, 51–52
cultural influences and, 41
developmental processes and, 45–47
disease impact on, 65
drug use/abuse hazards with, 59–60, 63
early stage of, 47–48
environmental hazards in, 56–64, 59,
117–118
environmental pollutants and, 63
exercise and, 66
fetal behavior and, 51–52
Vygotsky’s theory compared to, 156–157
weakness in, 142, 144
Piaget’s moral judgment theory, 555
autonomous morality stage in, 557
evaluation of, 557–558
morality of constraint stage of, 556
transitional period in, 556–557
Pictorial cues, 181, 181
Picture perception, 183
PKU. See Phenylketonuria
Placenta, 47, 48
Planning
adolescence improvements in, 400
challenges with, 153
problem solving and, 153, 155
Plant life status, preschooler’s understanding
of, 275
Plasticity, of brain, 114–116, 118
Play
active child theme in, 12–13, 98
adolescents and rules with, 13
definition of, 271
evolutionary perspective on, 364–365
fantasy, 13, 282, 517
“forbidden” toys and, 27
gender differences and, 363
gender segregation, 609, 609
numbers and board games for, 154, 306
obesity and lack of, 123
object substitution and, 271
pretend, 271–272, 514
puzzle, 284, 284–285
sociodramatic, 271–272
television and infants quality of, 31
Pleasure principle, 343
Pollutants, environmental, 63
Polychlorinated biphenyls (PCBs), 63
Polygenic inheritance, 93, 94
Popular children, 533, 534–535
Popularity
in adolescence, 534–535
longitudinal designs measuring, 33
popular children, 533, 534–535
Pornography concerns, 376
Positive affectivity, temperament dimension,
404, 405
Positive correlation, 29
Positive emotions, 388–389, 419
Positive ethnic identity, 452
Positive reinforcement, 201–202
Positron emission tomography (PET), 110
Possible/impossible events, infant cognition
studies and, 207, 207
Postcoventional moral reasoning, Kohlberg’s
stage of, 559, 559–560
Poverty
academic achievement and, 19
adolescence and, 19
children in, 19–20, 376–377, 377, 480, 480
as development hazard, 80
growth and maturation, 119–125
growth curves, 119, 120
height
adolescence and, 119, 119–120
age and continuity/discontinuity with, 16,
16
gender differences in, 119, 120
heritability and, 103
variability of, 120
hormones and, 120
nutritional behavior and, 121–125
preschoolers understanding of, 276
secular trends and, 120
stress impairing, 120
undernutrition and, 124–125, 125
variability of, 120
weight
gender differences in, 119, 120
obesity and, 122–124, 123
variability of, 120
Physical inactivity, television and, 375
Physical knowledge, infant cognitive
development and, 207–208, 208
Physics, informal theory of, 262
Piaget’s cognitive development theory,
132–145
accommodation in, 133
active child theme and, 131
assimilation in, 133
brief transitions in, 134
broad applicability in, 134
central development issues in, 133–135
centration and, 139–141, 288
child’s nature views of, 132–133
continuity/discontinuity and, 15, 131,
133–135
dynamic-systems theories compared to,
163–164
educational application of, 143
equilibration, disequilibrium in, 133–134
evaluating, 142, 144
infant spatial coding and, 284
intermodal perception of infants and,
186–187
invariant sequence in, 134
legacy of, 142, 144
main questions addressed by, 131
mechanisms of developmental change and,
648
nature and nurture in, 133
object permanence and, 131, 136, 144, 165,
206–207
practical benefits of, 130–131
qualitative change in, 134
sociocultural theories compared to, 155
stages of
concrete operations, 135, 141, 143
formal operations, 135, 141–142, 143
preoperational, 135, 138–141, 143
sensorimotor, 135–138, 143

SI-22 n S U B J E C T I N D E X
Prosocial behavior, 555
altruistic motives and, 569
cultural influences and, 562–563, 573
definition of, 562
development of, 569–571, 571
empathy and, 569–570
genetics contributing to, 572
individual differences in, 571–576
levels of, 562–563, 563
preschool children and, 568–569
school-based interventions promoting, 576
socialization of, 572–576
discipline and parenting style for, 575–576
modeling and communication of values for,
574, 574
opportunities for prosocial activities for,
574–575
sympathy and, 570, 571
Prosocial moral judgment, 562–563, 563
Prosocial motive, 420, 421
Prosody, 224
Proteins, 89
Pruning, synaptic, 113, 649
Psychic energy, 342
Psychoanalytic theories, 341–348
central developmental issues and, 342
current perspectives on, 347–348
Erikson’s psychosocial development theory,
345–348
Freud’s psychosexual development theory,
342–345, 347–348
view of child’s nature, 342
Psychoanalytic theory, 10
Psychological Care of Infant and Child (Watson),
350
Psychological control of children, by parents,
474
Psychology
evolutionary psychology theory, 596–597
friendship behavior effects and, 520–523
informal theory of, 262
naïve, 266–267
Psychopathology, 65
Psychosexual development theory. See Freud’s
psychosexual development theory
Psychosocial development theory. See Erikson’s
psychosocial development theory
Psychosocial moratorium, 447
Puberty, 453, 618
See also Adolescence and adolescents
Public policy issues
bilingual education and, 222
Carolina Abecedarian Project and, 318–319,
319, 663
child care program subsidies and, 665
child development knowledge informing,
4–5
child labor in Industrial Revolution and, 9
child witnesses and, 4–5, 665–666
China’s one-child policy and, 468–469
ethnic identity in, 450, 450–451
executive functions control of, 149
friends and nonfriends interaction of, 514–
515, 515
friendship choice in, 523–524
gender development milestones with,
608–610
gender-typed behavior in, 609–610
growth understanding of, 276
healing understanding of, 276–277
heredity understanding of, 275–276
illness understanding of, 276
imaginary companions and, 273
imagination of, 282
intention and, 237–238
knowledge of living things and, 273–278
language disorders and, 251
magic belief of, 282
maternal employment influence on, 499,
500
peer groups of, 525
phonemic awareness of, 322, 323–324
plant life status understanding of, 275
prewriting skills in, 328, 328
Project Head Start and, 317–320
prosocial behavior and, 568–569
strategy variability for, 152, 152–153
symbols and dual representation with, 252,
253–254
theory of mind and, 267–271, 268
time reasoning and, 288
vicarious reinforcement and, 352–353, 353,
354
Pretend play, 271–272, 514
Prewriting skills, 328, 328
Pride, development of, 392–393
Primary mental abilities, 300
Primates, as test subjects
brain sizes of, 364
communication and, 219, 219
Harlow’s research on, 427–428
infant face perception with, 176–177, 177
mirror neuron system and, 204
myelination and, 112
Private speech, 157, 244
Proactive aggression, 582
Problem solving
adolescence improvements in, 400
information-processing theories and, 146–
147, 152–153, 155, 357–358
microgenetic designs and, 34
motor development and, 162
planning and, 153, 155
toddlers and, 280–281, 281
Production, language, 217
Productive vocabulary, 232–235
Progesterone, 48
Project Head Start, 317–320, 503
Promoting Alternative Thinking Strategies
(PATHS), 538
Prenatal development (cont.)
fetal learning and, 40, 46, 54–56, 57
fetal memory and, 55
fetal movement in, 49–50, 51–52
fetal sensory experience and, 52–54
fetal vulnerability, gender differences in, 44,
44
gender differences in physical growth during,
617
hazards during, 56–66
historical perspective on, 41–42
hormones and, 47, 48, 59
illegal drugs and, 63
illustrated summary of, 48–51, 48–51
individual differences and, 40, 59
language development and, 56
learning and, 54–56, 55
legal drugs and, 59–60, 62–63
maternal emotional state and, 65–66
maternal factors in, 64–66
mercury impact on, 57
miscarriages and, 56
movement and, 49–50, 51–52
music perception and, 184–185
nature and nurture interaction and, 40,
638–639
nutrition, malnutrition and, 64–65
occupational hazards to, 63–64, 64
periods of, 44, 45
research and children’s welfare in, 40–41
sensitive period in, 57–59, 58
smell and, 46, 53, 55
sociocultural context and, 40
taste and, 46, 53, 55
touch and, 53
visual perception and, 53, 71
Prenatal stress, 65–66
Preoccupied adults, parental attachment status,
432, 433
Preoperational stage of cognitive development
(Piaget), 135, 138–141, 143
Prereaching movements, 193
Prereading skills, 323–324
Preschool and preschool-age children
aggression and, 578
categorization of, 264–266
causal reasoning and, 281
coaching of, 547–548
collective monologues of, 244
conception of self and, 441–443
conversational skills of, 244–246
delay of gratification and, 384
display rules and, 420–421, 421
drawing and, 254, 254–256, 255
emotional dynamics and causes
understanding of, 418–419
encoding and, 150–151, 152
Erikson’s psychosocial development theory
and, 346
essentialism and, 276

S U B J E C T I N D E X n SI-23
correlational, 28–32, 32
cross-sectional, 32–33, 35
experimental, 30–32, 32
longitudinal, 33, 35
microgenetic, 33–34, 35
developmental theories as framework and
motivation for, 130–131
ethical issues in, 35
historical foundations for, 7–10
on identity formation, 447–448
nonhuman animals and, 46
scientific method, 23–25, 36
Resilience
at-risk children and, 2–3, 80
developmental, 2–3, 80
failure and, 21–22
poverty and, 80
Respiratory system, development of, 52, 60,
61, 195
Retina, 174
Rhythm, music perception and, 185
Rhythmicity, temperament dimension, 404
Risk taking, gender differences with, 625
Ritalin, 370–371
Role behavior, ethnic, 450, 450
Role confusion, Erikson’s psychosocial
development theory, 346–347
Role taking, Selman’s stage theory of, 357
Romanian orphan adoption studies, 6–7, 116,
427, 640
Romantic relationships, with peers, 531–532
Rooting reflex, 189, 189
Rubella, 65, 95
Rumination, depression and, 396, 520, 614
Runaways, 481
Sadness, 391–392
Same-sex parents, 496–497
Sandy Hook tragedy, 554
Scaffolding
narratives, 245
social, 159–160
Scale errors, 196–197, 198
Schizophrenia
adoption studies and, 11, 105
genetics and heredity factors with, 11, 11
nature and nurture and, 11, 640
School and school-age children
bilingualism and, 222
classroom as community of leaders for, 161
conception of self and, 441–443
ethnic identity in, 450, 450–451
friendship evaluation of, 515, 515–517
gender development milestones in, 610–612
gender differences in physical growth for,
617–618
gender-typed behavior in, 611–612
hostile attributional bias problems for, 358
intelligence development and environmental
influence of, 312–313, 313
Reflexes
definition of, 189
disappearing, 192
motor development in infants and, 189,
189–190, 192, 201
sensorimotor stage of cognitive development
and, 136
types of, 189, 189, 192, 201
Regulator genes, 91, 95
Rehearsal, memory and, 151
Reinforcement
attention and, 351
imitation and, 353
positive, 201–202
vicarious, 352–353, 353, 354
Rejected children, 533, 535–537
adjustment problem risks of, 541, 541–543,
542
aggressive, 535–536, 541–542
gender and SES creating, 548, 548
peer acceptance fostered for, 538
performance problems of, 538
self-evaluation lacking in, 538
social competence and, 537
social knowledge lacking in, 538
social skills training for, 538
withdrawn, 536–537, 542
Rejecting-neglecting parenting style, 473, 473,
474–475
Relational aggression, 535, 578, 586
Relationship authenticity, 461
Relative size, pictorial cues, 181
Reliability, 24, 25
REM sleep. See Rapid eye movement sleep
Remarriage. See Stepparents
Repression, 344
Reproduction, sexual, 41–44, 91
Research and children’s welfare, as
developmental theme, 10, 21–22
at-risk children implications of, 662–664
education implications with, 662
families and, 470
intelligence and, 299
moral development and, 555
parenting implications of, 660–661
peer relationships and, 512
prenatal development and, 40–41
public policy improvements with, 664–666
social development theories and, 349
Research and research methods, 22–36
benefits of child development study and,
21–22
causation and, 29–30
child development theories based on, 10
data gathering and
interviews for, 25–26, 28
naturalistic observation for, 26–27, 28
structured observation for, 27–28, 28
design for
behavior genetics and, 99–102
intellectual development risks and, 315–316
maternity leave and, 664–665
Project Head Start and, 317–320
research and children’s welfare improving,
664–666
Punishment. See Discipline
Punishment and obedience orientation,
Kohlberg’s stage of, 559
Punitiveness, parental, 583–584
Puzzle play, 284, 284–285
Qualitative change, in Piaget’s cognitive
development theory, 134
Quiet-alert state, of newborns, 70, 70
Race
discrimination awareness and, 451
face preference and, 177
in friendship choice and selection, 524
intelligence development and, 315
parenting styles and, 475–476
poverty by, 19, 19
self-esteem in minority children, 462–463
See also specific groups
Raising children, 3–4
Random assignment, in experimental design,
30, 32
Random assortment, 91
Rapid eye movement sleep (REM sleep), 50,
52, 70–71, 71
Rational learning, 204–205, 650
Rats, as research subjects
in complex environment, 116–117
phylogenetic continuity and, 46
Reaching, 192–194, 194, 208, 209
Reactive aggression, 582
Reading
acquisition of skills for, 322–328
comprehension in, 325, 327
dyslexia in, 326, 326
individual differences in, 328
prereading, 323–324
stages of, 322–323
word identification in, 324–325
adolescent skills in, 323
comprehension monitoring for, 327
correlation of reading-test scores with hours
of, 29
dyslexia and, 95, 117, 326, 326
strategy-choice process in, 324–325, 325
Real emotions, false emotions compared to,
419–421, 420, 421
Reality principle, 343
Recessive alleles, 92
Recessive genes, 92
Reciprocal determinism, 354, 355
Reciprocal relationships, 429
Reciprocated best friendship, 520–521
Reference, language development problems
with, 231

SI-24 n S U B J E C T I N D E X
same-sex, 456
STDs and, 65
teen pregnancy and, 64
Sexual attraction
age of sexual minority youth recognition of,
455, 455
in puberty, 453
Sexual harassment, 631
Sexual identity or orientation, 453–458
college students and, 454
gender differences with, 454
milestones in, 455
origins of youth’s, 453
of parents, 496–497
in sexual minority youth, 454–458, 455
sexual orientation definition, 453
Sexual minority youth
child maltreatment of, 457
coming out consequences for, 456–458
coming out process for, 454–456, 455
definition of, 454
identity milestones for, 455
romantic relationships of, 531
sexual attraction recognition by age for, 455,
455
sexual identity in, 454–458, 455
suicide statistics with, 458
Sexually transmitted diseases (STDs), 65
Shame
development of, 392–393
Erikson’s psychosocial development theory
and, 346
guilt compared to, 393
Shape bias, 239, 239
Shared-environmental effects, 104–105, 312
Siblings
differential treatment of, 484
half-siblings, 485
peer groups and divergent experiences of,
105
relationships between, 483–485
rivalry and conflict of, 483, 485
subjective interpretations of, 21
Sickle-cell anemia, 94
SIDS. See Sudden infant death syndrome
Sight. See Visual perception and vision
Silent babbling, 230
“Simon Says,” 149
Single-parent families, poverty and, 19
Sitting, infants, 193
Skinner’s operant conditioning. See Operant
conditioning
SLC6A4 gene, 437, 568
Sleep
age and patterns of, 72
brain activity during REM, 71
circadian rhythms and, 52
cultural influences in arrangements for, 18,
18–19
newborn learning in, 71
Self-esteem, 458–464
aggression and high, 458–459
attractiveness and, 460
culture and, 463–464
definition of, 458
factors supporting, 641
individual differences and, 459, 658
in minority children, 462–463
nature and nurture and, 459
positive ethnic identity and high, 452
self-perception test for, 459
sociocultural context and, 459
sources of, 459–461
genetics and heredity, 460, 460
peer relationships, 460, 460–461
school and neighborhood, 461
Self-evaluation, rejected children lacking, 538
Self-identification, ethnic, 450, 450
Self-initiated activity, 642–643
Self-locomotion
egocentric spatial representations and, 284
motor development and, 194–198
Self-organization, dynamic-systems theories
and, 165–166
Self-protection, aggression for, 416
Self-protective motive, 421, 421
Self-reflective empathetic orientation, in
prosocial behavior, 563
Self-regulation
active child theme and, 643–644
emotional, 398–401, 418
gender differences and, 625
Self-socialization, 356, 599
Self-soothe, 399
Selman’s stage theory of role taking, 357
Semantic development, language and, 217
Sensation, 173
Senses, fetal experience of, 52–54
See also Auditory development and
preferences; Taste, sense of; Touch; Visual
perception and vision
Sensitive period
brain plasticity and, 116
definition of, 57
in prenatal development, 57–59, 58
See also Critical period
Sensitivity, parental, 435–437
Sensorimotor stage of cognitive development
(Piaget), 135–138, 143
Sensory neurons, 106
Sentence formation, 242
Separation anxiety, 391, 391, 429
Serotonin, 437
SES. See Socioeconomic status
Sex, gender compared to, 595
Sex chromosomes, 90, 92–93, 94
Sex-linked inheritance, 94
Sexual activity
conception and, 42–44, 45
romantic relationships and, 531–532
School and school-age children (cont.)
interviews revealing student feeling about,
25–26
IQ as predictor of academic achievement in,
306, 307, 307–308
language development role of, 235
maternal employment influence on, 499, 500
parental gatekeeping and, 547
phonological recoding skills of, 322, 324
prosocial behavior promoted by, 576
reciprocated best friendship among, 520–521
as self-esteem source, 461
social comparison of, 442
speed perceived by, 143
time reasoning and, 288
vocabulary of, 246
School shootings, 554
Scientific method, 36
appropriate measurement in, 23–25, 25
definition of, 23
Script, 329, 329
SD. See Standard deviation
Search/moratorium, ethnic identity, 451–452
Second-language, bilingualism and, 222
Secular trends, physical growth and, 120
Secure adults, parental attachment status, 432,
433
Secure attachment, 436
academic achievement and, 438
definition and categorization of, 431
factors associated with, 435–437
in infants and toddlers, 437–439
long-term effects of, 437–439
parental sensitivity and, 435–437
parents forming, 661
peer relationships and, 437–438
stability of, 437–439
Secure base, caregiver as, 428
Segregation, of objects, 179, 179–180
Selection, dynamic-systems theories and,
166–167
Selective attention, information-processing
theories and, 151
Self, conception of, 439–449
adolescence development of, 443–446, 444
childhood development of, 441–443
continuity/discontinuity and, 647–648
development of, 440–446
in infancy, 440–441
parents contributing to, 441
peer relationships and, 443–446
self, definition of, 439
self-esteem, 458–464
See also Identity
Self-attributions, Dweck’s theory of, 359–361
Self-conscious emotions, 392–394
Self-discipline, 307
Self-disclosure, to friends and parents by age,
518, 518
Self-efficacy, perceived, 354–355

S U B J E C T I N D E X n SI-25
childhood and
in different circumstances within society,
655–656
in different times and places, 655
in societies with different values and
practices, 653–655
cognitive development and, 654–655
components of, 17–18
conceptual development and, 260
definition of, 17
emotional development and, 385
families and, 469, 475
gender development and, 595
identity formation and, 449
infants and, 173
intelligence and, 299
language development and, 216, 230–231
moral development and, 555, 572–576
peer relationships and, 511
prenatal development and, 40
questions about, 10
self-esteem and, 459
SES and, 655–656
social development theories and, 362
survival and, 44
See also Cultural influences
Sociocultural theories of cognitive
development, 144, 155–161
central developmental issues with, 158–160
children as products of cultural influences in,
157–158
children as teachers and learners in, 157
child’s nature view of, 156–158
definition of, 155
educational applications of, 161
guided participation and, 155–156
intersubjectivity and, 159, 231
main questions addressed by, 131
Piaget’s cognitive development theory
compared to, 155
pretend play and, 272
private speech and, 157, 244
social referencing and, 197, 417
of Vygotsky, 156–157
Sociodramatic play, 271–272
Socioeconomic status (SES)
affluence, developmental challenges with,
377–378
of African Americans, 19, 19, 80
antisocial behavior and, 585–586
child care and, 503
definition of, 19
development effects of, 376–378, 377
as development hazard, 80
environment and, 87–88
family communication and, 479
of Hispanic Americans, 19, 19, 80
infant feeding and, 121
IQ and, 103, 307, 307–308, 314, 314–315
language development and, 235
Social judgment domains, 563–566
age of differentiating, 564
children’s use of, 564–565
cultural differences with, 565
families and, 564–565
SES and, 565–566
types of, 563–564
Social knowledge
infant cognitive development and, 208–211,
209, 210
rejected children lacking, 538
Social learning theory, 352–355, 650–651
Social managers, parents as, 472
Social media, 373, 529–530
Social networks
in adolescence, 526–528
in early adolescence, 526
negative influences of, 528, 531
Social policy. See Public policy issues
Social referencing, 197, 417
Social reform movements, 9
Social role theory, 607
Social scaffolding, 159–160
Social skills training
definition, 539
for rejected children, 538
temperament in, 408–409
Social smiles, of infants, 388
Social systems and conscience orientation,
Kohlberg’s stage of, 559
Social-compensation hypothesis, 529
Socialization
aggression and, 521
of antisocial behavior, 583–586, 587–589
child care adjustments and, 502–503
definition of, 411
parental
of children’s emotional responding,
411–414
family influence of, 472–482
of prosocial behavior, 572–576
styles and practices of, 472–482
of prosocial behavior, 572–576
discipline and parenting style for, 575–576
modeling and communication of values for,
574, 574
opportunities for prosocial activities for,
574–575
Societal influence on intelligence, 313–320
Flynn effect and, 313–314, 314
poverty and, 314, 314–315
programs for helping poor children and,
317–320
race, ethnicity and, 315
risk factors in development and, 315–317, 316
Society for Research on Child Development
(SRCD), 35
Sociocultural context, as developmental theme
attachment and, 427
child care and, 18
as newborn state of arousal, 70–72, 71
non-REM, 70–71, 71
REM, 50, 52, 70–71, 71
SIDS and, 60, 61, 195
sleep–wake cycles of infants, 72
Sleeper effects, 59
Sleep–wake cycles, of infants, 72
SLI. See Specific language impairment
Slow-to-warm up babies, 404
Small for gestational age, 76
Smarties task, theory of mind and, 268,
268–269
Smell, sense of, 46, 53, 55, 186
Smoking, 60, 61
Social cognition theories
antisocial behavior, aggression and, 582
Bandura’s social cognitive theory, 352–354
central development issues and, 356–357
current theories on, 361
Dodge’s information-processing theory of
social problem solving, 357–358
Dweck’s theory of self-attributions and
achievement motivation, 359–361
gender development and, 603–604, 606
Selman’s stage theory of role taking, 357
view of child’s nature, 356
Social comparison, 442
Social competence
definition of, 401
emotional regulation and, 401
emotional self-regulation and, 418
family stress and, 548, 548
friendship and development of, 519
negative emotions and, 412
peer relationships with parental attachment
and, 544–545
rejected children and, 537
temperament and, 408–409
Social contract or individual rights orientation,
Kohlberg’s stage of, 559
Social conventional judgments, 564–566
Social development theories, 339–381
active child theme and, 341, 362
central developmental issues in, 342, 349,
356–357, 362
continuity/discontinuity and, 342, 349, 356,
362
ecological theories, 362–379
individual differences and, 341, 342, 356
learning theories, 348–356
mechanisms of change and, 349
nature and nurture and, 341, 342, 362
psychoanalytic theories, 341–348
research and children’s welfare and, 349
social cognition theories, 352–354, 356–
362
sociocultural context and, 362
view of child’s nature, 342, 349, 356, 362
See also individual theories
Social identity theory, 602–603

SI-26 n S U B J E C T I N D E X
social competence of children and family,
548, 548
Strongly internalized stage, in prosocial
behavior, 563
Structured interview, 25, 28
Structured observation, 27–28, 28
Study of child development
historical foundations for, 7–10
intelligence and, 21
methods for, 22–36
reasons for, 3–7
Subitizing, 290–291
Subjective contour, 178, 178
Subordinate level, category hierarchies, 263,
264–265
Substance abuse. See Alcohol abuse; Drug use/
abuse
Subtraction, strategy choices for, 331
Successful intelligence, theory of, 321–322
Sucking reflex, 50, 50, 189, 189, 201
Sudden infant death syndrome (SIDS), 60,
61, 195
Suicide statistics, with sexual minority youth,
458
Superego, 344
Superordinate level, category hierarchies, 263,
264–265
Support, friendship for, 517–518
Support relations, infant cognitive
understanding of, 207–208, 208
Survival of offspring, parental-investment
theory and, 365
Swaddling, 73
Swallowing, fetal, 52
Swallowing reflex, 189
Sweet taste
fetal preference for, 53
food preferences and eating regulation with,
122
infant preference for, 74, 122
Symbolic numerical magnitudes, 332
Symbolic representation, preoperational stage
of cognitive development, 138, 138
Symbols
definition of, 216
drawing and, 254, 254–256, 255
dual representation and, 252, 253–254
as information, 253–254
language development and nonlinguistic,
252–256
Sympathy
parenting strategies expressing, 3–4
prosocial behavior development and, 570,
571
Synapse elimination, 113, 114
Synapses, 106, 106, 116
Synaptic pruning, 113, 649
Synaptogenesis, 112, 112–113, 648–649
Syntactic bootstrapping, 239–241, 240
Syntactic development, language and, 218
over time, individual differences and, 658
perceptual constancy and, 178
of secure attachment, 437–439
sitting and, 193
of sociometric peer status, 539
of temperament over time, 408
Stable order, counting and, 291
Stage theories of development
continuity/discontinuity in developmental
and, 15, 133–135, 646–648
definition of, 15
Erikson’s psychosocial development theory
and, 15, 345–348
Freud’s psychosexual theory and, 15, 342–
345, 347–348
Kohlberg’s theories
of cognitive development, 600
on moral judgment, 558, 558–561, 560
Piaget’s theory
of cognitive development, 15, 132–145,
156–157, 163–164, 284, 288, 648
of moral judgment, 555–558
Selman’s stage theory of role taking, 357
Standard deviation (SD), 304–305
Stanford-Binet intelligence test, 302
States of arousal, newborns
crying, 70, 70, 72–74
definition of, 70
sleep and, 70–72
Statistical learning, 200–201, 650
STDs. See Sexually transmitted diseases
Stem cells, embryonic, 45
Stepparents
adolescence and challenges with, 495
African Americans and, 496
child maltreatment and, 365, 365
cultural influences on, 496
discipline and, 495
factors affecting children’s adjustment to,
495–496
noncustodial parents interactions with, 496
questions caused by, 494
United States family trends and changes
with, 494–496
Stepping reflex, 192
Stereopsis, depth perception and, 181
“Sticky mittens” intervention, 193
“Strange disease,” 57
Strange Situation, attachment and, 430,
430–433, 434
Strategy-choice process, in reading, 324–325,
325
Stress
awareness of control of, 401
divorce causing, 490–491, 491
economic, 480, 480, 482
neurogenesis and, 109
physical growth impaired by, 120
poverty and, 548, 586
prenatal, 65–66
Socioeconomic status (SES) (cont.)
malnutrition and, 65, 124–125
media inequities with, 375–376
parenting styles influenced by, 475–476,
479–482
economic stress and, 480, 480, 482
homelessness and, 481
prereading skills and, 323
rejected children and, 548, 548
social judgment domains and, 565–566
sociocultural context and, 655–656
teen pregnancy and, 64
See also Poverty
Sociometric status, 533, 533–539
See also Peer status
Soft assembly, 165
Sole custody, 493
Soothing, for crying infant, 73–74, 399
Sour tastes, food preferences, 122
Spanking children, 3
Spatial ability
of blind and visually impaired people, 285
cerebral cortex and, 283
conceptual development and, 283–286,
292–293
egocentric spatial representations and, 284
empiricist and nativist views on, 283
external environment and, 285–286
gender differences with, 620, 620
infant representations of space and, 283–285
Piaget’s cognitive development theory on
infant, 284
puzzle play and, 284, 284–285
time and number relations with, 292–293
Spatial intelligence (Gardner), 321
Species-specific behavior, language and, 219
Species-universal behavior, language and, 219
Specific language impairment (SLI), 251
Speech
distributional properties of, 228–229
fetal recognition of, 54–55, 56
foreign-language perception of, 227, 227
perception of, 224–228
preparation for production of, 229–231
private, 157, 244
sensitivity to regularities in, 228–229
telegraphic, 242
See also Auditory development and
preferences; Language development
Speed, school-age children perception of, 143
Sperm, 42–44, 43, 91
Spermarche, 618
Spina bifida, origins of, 47
Spines, on dendrites, 111–112, 116
Spontaneous abortion. See Miscarriages
SRCD. See Society for Research on Child
Development
Stability
gender, 600
IQ scores showing, 645

S U B J E C T I N D E X n SI-27
Unconscious, 344
Undernutrition, 124–125, 125
United States
academic achievement and employment in,
314, 314–315
attachment in, 434
Balinese childbirth practices compared to,
68–69
birth weight averages in, 76
childhood poverty in, 376–377, 377, 480,
480
coming out acceptance challenges in,
456–457
counting in, 291–292, 292
emotional development in, 414–416
emotional expression in, 654
family changes in, 485–498
IDS in, 223
independence promoted by, 158
infant feeding in, 121
infant mortality in, 74–75, 75
Kenya newborn sleep–wake cycles compared
to, 72
labeling objects in, 234
motor development milestones and, 190–191
obesity in, 122–124, 123
peer status and, 539–540
peer status predicting academic achievement
in, 540–541, 541
peer support for academic achievement in,
623–624
picture perception in, 183
romantic relationships by age in, 531
self-esteem in, 463–464
social judgment domains in, 565
speech perception in, 226
violence levels in, 632–633
See also African Americans; Asian
Americans; European Americans;
Families, United States changes in;
Hispanic Americans; Mexican Americans
Universal ethical principles, Kohlberg’s stage
of, 559
Universal Grammar, 248–249
University students. See College/university
students
Unresolved/disorganized adults, parental
attachment status, 432, 433
Uterus, 43
Utterance, length of, 242, 242
Vaccines, 95
Vagal tone/suppression, 406
Vagina, 42–43, 43
Validation, friendship for, 517–518
Validity, 24–25, 25
Values, sociocultural context and, 653–655
Variables, 28, 31
Verbal Behavior (Skinner), 247
Verbal skills, gender differences in, 620
Text messaging, 529–530, 530
Thalidomide, 57–58, 91
Theory of mind, conceptual development and,
267–271, 268
Theory of mind module (TOMM), 269–270
Theory of successful intelligence, 321–322
Third-variable problem, 29, 32
Three mountain task (Piaget), 138, 138
3-day measles, 65
Three-stratum theory of intelligence, 300–
301, 301
Thyroid gland, 120
Thyroxine, 120
Time, conceptual development of, 286–288,
292–293, 647
Time-out, 4, 351
Timing
auditory development and, 639
as crucial in nature and nurture, 7
grammar development and, 639–640
with interventions for at-risk children,
662–663
nature and nurture with matters of, 439–440
See also Critical period
Toddlers. See Infants and toddlers
TOMM. See Theory of mind module
Tonic neck reflex, 189, 189
Touch
infant perception and, 186
infant soothing with, 73–74
prenatal development and, 53
Tourette syndrome, 95
Transgender youth, 599
Transitional level, in prosocial behavior, 563
Transitional period, Piaget’s stages and,
556–557
Triadic model of reciprocal causation, 603
Tuition, 603
Turkey, infant swaddling in, 73
Turner syndrome, 94
Turn-taking, in communication, 230–231
“Turtle technique,” for anger management, 4
Twin studies
design of, 100
family IQ and, 100, 100–102
reared apart, 101
schizophrenia and, 11, 11
shared-environmental effects and, 104–105,
312
Twins, development of, 47
Tylenol (acetaminophen), 60
UCR. See Unconditioned response
UCS. See Unconditioned stimulus
Uganda, research in, 429
Ukraine, research in, 436–437
Ultrasound, 52
Umbilical cord, 48
Unconditioned response (UCR), 201
Unconditioned stimulus (UCS), 201
Syntax, 218
Systematic desensitization, 350
“Tabula rasa,” 8
Taiwan, research in, 368
Tamang, Nepal, 415
Task analysis, information-processing theories
and, 146
Taste, sense of
of infants
feeding and, 122
perception of, 122, 186
for soothing, 74
prenatal development and, 46, 53, 55
Tay-Sachs disease, 94
Teachers, children as, 157
Technology, language acquisition and, 240–
241
Teen pregnancy, 64
Telegraphic speech, 242
Television watching
consumption hours in, 605
education with, 372
as heritable, 103
infant quality of play and, 31
obesity and, 123–124
physical inactivity and, 375
violence and, 374–375
vocabulary building and, 240–241
See also Media, influence on children
Temperament
of adolescents, 581–582
age and, 406
antisocial behavior and, 581–582
behavioral inhibition and, 409
cortisol reactivity and, 407
definition of, 403
EEG measurement of, 406–407, 407
emotional development and, 403–410
goodness of fit and, 409
as heritable, 103
individual differences and, 403
of infants, 403–405, 405
measurement of, 406–407
nature and nurture and, 403
parenting style influenced by child’s, 477–
479, 478
Rothbart’s scales of, 404, 405
social competence and, 408–409
in social skills training and maladjustment,
408–409
stability of, over time, 408
Temporal lobe, 108, 108
Teratogens, 57, 59
Test and exploration period, in coming out,
456
Testimony, public policy for children giving
eyewitness, 4–5, 665–666
Testosterone, 47
Test-retest reliability, 24, 25

SI-28 n S U B J E C T I N D E X
Weight
gender differences in, 119, 120
obesity and, 122–124, 123
variability in, 120
White Americans. See European Americans
Williams syndrome, 94–95
WISC. See Wechsler Intelligence Scale for
Children
Withdrawing acts, 627, 627
Withdrawn-rejected children, 536–537, 542
Witnesses, public policy for children as, 4–5,
665–666
Word identification, reading skills and,
324–325
Word segmentation, 228–229
Words. See First words
Working memory, 147–148
World War II children
Bowlby’s studies on, 426
Freud, Anna’s, concentration camp survivor
study on, 510–511
Netherlands prenatal nutrition study on,
65
orphan studies on, 426
Writing, acquisition of skills for, 328–330
Wru and Wrugbe, in Beng culture, 41
X chromosomes, 90, 90, 92–93, 94
XX chromosomes (female), 90
XY chromosomes (male), 90
Y chromosomes, 90, 90, 92
Zuni Indians, self-conscious emotions and,
393
Zygote, 44, 47
object segregation and, 179, 179–180
optical expansion of, 180–181
picture perception of, 183
study of, 173–182
visual acuity and, 174, 174–175
visual scanning of, 175, 175, 176–177
motor development interaction with, 193
patterns and, 175, 178, 201
prenatal development and, 53, 71
scale errors and, 196–197, 198
Visual scanning, 175, 175
Visually based retrieval, 324
Visually impaired people, spatial ability and,
285
Vocabulary
of college students, 246
comprehension, 231–232
holophrastic period with, 234
nouns in early, 233
productive, 232–235
of school-age children, 246
spurt, 236
television watching and building, 240–241
See also First words
Vocalizations, infant, 229–231, 230
Voice onset time (VOT), 225
Voices, fetal hearing and, 54–55, 56
VOT. See Voice onset time
Vulnerability
experience-expectant plasticity and, 115
gender differences in fetal, 44, 44
Watson’s behaviorist theory. See Behaviorist
theory
Wechsler Intelligence Scale for Children
(WISC), 302, 303
Vicarious reinforcement, 352–353, 353, 354
Victimized children, peer status and, 542–543
Violation-of-expectancy procedure, 205,
206–207
Violence
adolescent antisocial behavior and, 577–579,
579
cultural influences on, 632
dating, 631
Fast Track intervention program for, 588–
589, 589
gangs and, 586
media and, 374–375
parental conflict influencing, 585
United States levels of, 632–633
See also Aggression
Visual acuity, of infants, 174, 174–175
Visual cliff, fear of heights and, 196–197, 390,
391
Visual perception and vision
binocular disparity and, 181
blindness and, 115–116
cerebral cortex and, 173–174
depth perception and, 180–182, 181, 182
faces, infant attention to, 12, 187
attractiveness of, 177
infant preferences with, 176, 176–177, 177
infant visual scanning of, 175, 175,
176–177
habituation and, 174
infants and
cataracts in, 115
color discrimination of, 174–175, 264
depth perception and, 180–182, 181, 182
movement and, 175
object perception and, 178–180

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develop
How Children
Robert Siegler Judy DeLoache Nancy Eisenberg Jenny Saffran
F o u r t h E d i t i o n
This is an exciting time in the field of child development. The past decade has brought new theories, new ways
of thinking, new areas of research, and innumerable new findings to the field. We originally wrote How Children
Develop to describe this ever improving body of knowledge of children and their development and to convey our
excitement about the progress that is being made in understanding the developmental process. We are pleased to
continue this endeavor with the publication of the Fourth Edition of How Children Develop.
—From the Preface
As new research expands the field’s understanding of child and adolescent development, the authors of How Chil-
dren Develop continue their commitment to bringing the story of today’s developmental science to the classroom in
a clear and memorable way. Joined in this Fourth Edition by Jenny Saffran of the University of Wisconsin–Madison,
they maintain their signature emphasis on the “Seven Classic Themes” of development, which facilitates students’
understanding by highlighting the fundamental questions posed by investigators past and present. The new and ex-
panded coverage in the Fourth Edition spans a wide range of topics—from broad areas like the epigenetic aspects
of development, the links between brain function and behavior, and the pervasive influence of culture to specific
subjects such as the mechanisms of infants’ learning, the effects of math anxiety, and the rapidly growing influence
of social media in children’s and adolescents’ lives. This edition also features the highly anticipated debut of Launch-
Pad, an online learning system that features Worth Publishers’ celebrated video collection; the full e-Book of How
Children Develop; and the LearningCurve quizzing system, which offers students instant feedback on their learning.
Learn more about and request access at www.worthpublishers.com/launchpad.
Order How Children Develop, Fourth Edition, with LaunchPad at no additional cost by using
ISBN 10: 1-4641-8284-1 / ISBN-13: 978-1-4641-8284-6.
Coverage of contemporary developmental science is very important to me. I prefer a text that describes the relevant
research and is updated regularly. I find How Children Develop to be very good in this area, as all of the authors are
primarily researchers.
—Jeffery Gagne, University of Texas at Arlington
I highly recommend this textbook. The main strengths are up-to-date research with clear descriptions of study
methods and findings as well as excellent real-world examples that get students interested in a topic so that they are
excited enough to read about the research and evidence that support real-world developmental phenomenon. I do
not think the text has a major weakness.
—Katherine O’Doherty, Bowdoin College
Since its inception, I think that How Children Develop is the best child development textbook available. I would not
hesitate to use it again in my classes.
—Richard Lanthier, George Washington University
www.worthpublishers.com
Cover art: Football, Bentota, Sri Lanka, 1998 (oil on canvas)
©Andrew Macara / Private Collection / The Bridgeman Art Library
develop
H
o
w
C
h
ild
re
n
W O R T H
F o u r t h
E d i t i o n
Siegler
DeLoache
Eisenberg
Saffran

Title Page
Copyright
About the Authors
Contents
Preface
CHAPTER 1: An Introduction to Child Development
Reasons to Learn About Child Development
Raising Children
Choosing Social Policies
Understanding Human Nature
Review
Historical Foundations of the Study of Child Development
Early Philosophers’ Views of Children’s Development
Social Reform Movements
Darwin’s Theory of Evolution
The Beginnings of Research-Based Theories of Child Development
Review
Enduring Themes in Child Development
1. Nature and Nurture: How Do Nature and Nurture Together Shape Development?
2. The Active Child: How Do Children Shape Their Own Development?
3. Continuity/Discontinuity: In What Ways Is Development Continuous, and in What Ways Is It Discontinuous?
4. Mechanisms of Development: How Does Change Occur?
5. The Sociocultural Context: How Does the Sociocultural Context Influence Development?
6. Individual Differences: How Do Children Become So Different from One Another?
7. Research and Children’s Welfare: How Can Research Promote Children’s Well-Being?
Review
Methods for Studying Child Development
The Scientific Method
Contexts for Gathering Data About Children
Correlation and Causation
Designs for Examining Development
Ethical Issues in Child-Development Research
Review

CHAPTER 2: Prenatal Development and the Newborn Period
Prenatal Development
Box 2.1: A Closer Look: Beng Beginnings
Conception
Box 2.2: Individual Differences: The First—and Last—Sex Differences
Developmental Processes
Box 2.3: A Closer Look: Phylogenetic Continuity
Early Development
An Illustrated Summary of Prenatal Development
Fetal Behavior
Fetal Experience
Fetal Learning
Hazards to Prenatal Development
Box 2.4: Applications: Face Up to Wake Up
Review
The Birth Experience
Diversity of Childbirth Practices
Review
The Newborn Infant
State of Arousal
Negative Outcomes at Birth
Box 2.5: Applications: Parenting a Low-Birth-Weight Baby
Review
CHAPTER 3: Biology and Behavior
Nature and Nurture
Genetic and Environmental Forces
Box 3.1: Applications: Genetic Transmission of Disorders
Behavior Genetics
Box 3.2: individual Differences: Identical Twins Reared Apart
Review
Brain Development
Structures of the Brain
Developmental Processes
Box 3.3: A Closer Look: Mapping the Mind
The Importance of Experience
Brain Damage and Recovery
Review
The Body: Physical Growth and Development
Growth and Maturation
Nutritional Behavior
Review

CHAPTER 4: Theories of Cognitive Development
Piaget’s Theory
View of Children’s Nature
Central Developmental Issues
The Sensorimotor Stage (Birth to Age 2 Years)
The Preoperational Stage (Ages 2 to 7)
The Concrete Operational Stage (Ages 7 to 12)
The Formal Operational Stage (Age 12 and Beyond)
Piaget’s Legacy
Box 4.1: Applications: Educational Applications of Piaget’s Theory
Review
Information-Processing Theories
View of Children’s Nature
Central Developmental Issues
Box 4.2: Applications: Educational Applications of Information-Processing Theories
Review
Sociocultural Theories
View of Children’s Nature
Central Developmental Issues
Review
Box 4.3: Applications: Educational Applications of Sociocultural Theories

Dynamic-Systems Theories
View of Children’s Nature
Central Development Issues
Box 4.4: Applications: Educational Applications of Dynamic-Systems Theories
Review

CHAPTER 5: Seeing, Thinking, and Doing in Infancy
Perception
Vision
BOX 5.1: A Closer Look: Infants’ Face Perception
BOX 5.2: A Closer Look: Picture Perception
Auditory Perception
Taste and Smell
Touch
Intermodal Perception
Review
Motor Development
Reflexes
Motor Milestones
Current Views of Motor Development
BOX 5.3: A Closer Look: “The Case of the Disappearing Reflex”
The Expanding World of the Infant
BOX 5.4: Applications: A Recent Secular Change in Motor Development
BOX 5.5: A Closer Look: “Gangway—I’m Coming Down”
Review
Learning
Habituation
Perceptual Learning
Statistical Learning
Classical Conditioning
Instrumental Conditioning
Observational Learning/Imitation
Rational Learning
Review
Cognition
Object Knowledge
Physical Knowledge
Social Knowledge
Looking Ahead
Review

CHAPTER 6: Development of Language and Symbol Use
Language Development
The Components of Language
What Is Required for Language?
Box 6.1: Applications: Two Languages Are Better Than One
The Process of Language Acquisition
Box 6.2: Individual Differences: The Role of Family and School Context in Early Language Development
Box 6.3: Applications: iBabies: Technology and Language Learning
Theoretical Issues in Language Development
Box 6.4: A Closer Look: “I Just Can’t Talk Without My Hands”: What Gestures Tell Us About Language
Box 6.5: Individual Differences: Developmental Language Disorders
Review
Nonlinguistic Symbols and Development
Using Symbols as Information
Drawing
Review

CHAPTER 7: Conceptual Development
Understanding Who or What
Dividing Objects into Categories
Knowledge of Other People and Oneself
Box 7.1: Individual Differences: Children with Autism Spectrum Disorders (ASD)
Box 7.2: Individual Differences: Imaginary Companions
Knowledge of Living Things
Review
Understanding Why, Where, When, and How Many
Causality
Box 7.3: A Closer Look: Magical Thinking and Fantasy
Space
Time
Number
Relations Among Understanding of Space, Time, and Number
Review

CHAPTER 8: Intelligence and Academic Achievement
What Is Intelligence?
Intelligence as a Single Trait
Intelligence as a Few Basic Abilities
Intelligence as Numerous Processes
A Proposed Resolution
Review
Measuring Intelligence
The Contents of Intelligence Tests
The Intelligence Quotient (IQ)
Continuity of IQ Scores
Box 8.1: Individual Differences: Gifted Children
Review
IQ Scores as Predictors of Important Outcomes
Review
Genes, Environment, and the Development of Intelligence
Qualities of the Child
Influence of the Immediate Environment
Influence of Society
Box 8.2: Applications: A Highly Successful Early Intervention: The Carolina Abecedarian Project
Review
Alternative Perspectives on Intelligence
Review
Acquisition of Academic Skills: Reading, Writing, and Mathematics
Reading
Box 8.3: Individual Differences: Dyslexia
Writing
Mathematics
Mathematics Anxiety
Box 8.4: Applications: Mathematics Disabilities
Review

CHAPTER 9: Theories of Social Development
Psychoanalytic Theories
View of Children’s Nature
Central Developmental Issues
Freud’s Theory of Psychosexual Development
Erikson’s Theory of Psychosocial Development
Current Perspectives
Review
Learning Theories
View of Children’s Nature
Central Developmental Issues
Watson’s Behaviorism
Skinner’s Operant Conditioning
Social Learning Theory
Box 9.1: A Closer Look: Bandura and Bobo
Current Perspectives
Review
Theories of Social Cognition
View of Children’s Nature
Central Developmental Issues
Selman’s Stage Theory of Role Taking
Dodge’s Information-Processing Theory of Social Problem Solving
Dweck’s Theory of Self-Attributions and Achievement Motivation
Current Perspectives
Review
Ecological Theories of Development
View of Children’s Nature
Central Developmental Issues
Ethological and Evolutionary Theories
The Bioecological Model
Box 9.2: Individual Differences: Attention-Deficit Hyperactivity Disorder
Box 9.3: Applications: Preventing Child Abuse
Current Perspectives
Review

CHAPTER 10: Emotional Development
The Development of Emotions in Childhood
Theories on the Nature and Emergence of Emotion
The Emergence of Emotion in the Early Years and Childhood
Box 10.1: Individual Differences: Gender Differences in Adolescent Depression
Review
Regulation of Emotion
The Development of Emotional Regulation
The Relation of Emotional Self-Regulation to Social Competence and Adjustment
Review
Individual Differences in Emotion and Its Regulation
Temperament
Box 10.2: A Closer Look: Measurement of Temperament
Review
Children’s Emotional Development in the Family
Quality of the Child’s Relationships with Parents
Parental Socialization of Children’s Emotional Responding
Review
Culture and Children’s Emotional Development
Review
Children’s Understanding of Emotion
Identifying the Emotions of Others
Understanding the Causes and Dynamics of Emotion
Children’s Understanding of Real and False Emotions
Review

CHAPTER 11: Attachment to Others and Development of Self
The Caregiver–Child Attachment Relationship
Attachment Theory
Measurement of Attachment Security in Infancy
Box 11.1: Individual Differences: Parental Attachment Status
Cultural Variations in Attachment
Factors Associated with the Security of Children’s Attachment
Box 11.2: Applications: Interventions and Attachment
Does Security of Attachment Have Long-Term Effects?
Review
Conceptions of the Self
The Development of Conceptions of Self
Identity in Adolescence
Review
Ethnic Identity
Ethnic Identity in Childhood
Ethnic Identity in Adolescence
Review
Sexual Identity or Orientation
The Origins of Youths’ Sexual Identity
Sexual Identity in Sexual-Minority Youth
Review
Self-Esteem
Sources of Self-Esteem
Self-Esteem in Minority Children
Culture and Self-Esteem
Review

CHAPTER 12: The Family
Family Dynamics
Box 12.1: A Closer Look: Parent–Child Relationships in Adolescence
Review
The Role of Parental Socialization
Parenting Styles and Practices
The Child as an Influence on Parenting
Socioeconomic Influences on Parenting
Box 12.2: A Closer Look: Homelessness
Review
Mothers, Fathers, and Siblings
Differences in Mothers’ and Fathers’ Interactions with Their Children
Sibling Relationships
Review
Changes in Families in the United States
Box 12.3: Individual Differences: Adolescents as Parents
Older Parents
Divorce
Stepparenting
Lesbian and Gay Parents
Review
Maternal Employment and Child Care
The Effects of Maternal Employment
The Effects of Child Care
Review

CHAPTER 13: Peer Relationships
What Is Special About Peer Relationships?
Friendships
Early Peer Interactions and Friendships
Developmental Changes in Friendship
The Functions of Friendships
Effects of Friendships on Psychological Functioning and Behavior over Time
Box 13.1: Individual Differences: Culture and Children’s Peer Experience
Children’s Choice of Friends
Review
Peers in Groups
The Nature of Young Children’s Groups
Cliques and Social Networks in Middle Childhood and Early Adolescence
Cliques and Social Networks in Adolescence
Negative Influences of Cliques and Social Networks
Box 13.2: A Closer Look: Cyberspace and Children’s Peer Experience
Cyberspace and Children’s Peer Experience (continued)
Romantic Relationships with Peers
Review
Status in the Peer Group
Measurement of Peer Status
Characteristics Associated with Sociometric Status
Box 13.3: Applications: Fostering Children’s Peer Acceptance
Stability of Sociometric Status
Cross-Cultural Similarities and Differences in Factors Related to Peer Status
Peer Status as a Predictor of Risk
Review
The Role of Parents in Children’s Peer Relationships
Relations Between Attachment and Competence with Peers
Quality of Ongoing Parent–Child Interactions and Peer Relationships
Parental Beliefs
Gatekeeping and Coaching
Family Stress and Children’s Social Competence
Review

CHAPTER 14: Moral Development
Moral Judgment
Piaget’s Theory of Moral Judgment
Kohlberg’s Theory of Moral Judgment
Prosocial Moral Judgment
Domains of Social Judgment
Review
The Early Development of Conscience
Factors Affecting the Development of Conscience
Review
Prosocial Behavior
The Development of Prosocial Behavior
The Origins of Individual Differences in Prosocial Behavior
BOX 14.1: A Closer Look: Cultural Contributions to Children’s Prosocial and Antisocial Tendencies
BOX 14.2: Applications: School-Based Interventions for Promoting Prosocial Behavior
Review
Antisocial Behavior
The Development of Aggression and Other Antisocial Behaviors
Consistency of Aggressive and Antisocial Behavior
BOX 14.3: A Closer Look: Oppositional Defiant Disorder and Conduct Disorder
Characteristics of Aggressive-Antisocial Children and Adolescents
The Origins of Aggression
Biology and Socialization: Their Joint Influence on Children’s Antisocial Behavior
BOX 14.4: Applications: The Fast Track Intervention
Review

CHAPTER 15: Gender Development
Theoretical Approaches to Gender Development
Biological Influences
Box 15.1: A Closer Look: Gender Identity: More than Socialization?
Cognitive and Motivational Influences
Box 15.2: A Closer Look: Gender Typing at Home
Box 15.3: Applications: Where Are SpongeSally SquarePants and Curious Jane?
Cultural Influences
Review
Milestones in Gender Development
Infancy and Toddlerhood
Preschool Years
Middle Childhood
Adolescence
Box 15.4: A Closer Look: Gender Flexibility and Asymmetry
Review
Comparing Girls and Boys
Physical Growth: Prenatal Development Through Adolescence
Cognitive Abilities and Academic Achievement
Personality Traits
Interpersonal Goals and Communication
Box 15.5: A Closer Look: Gender and Children’s Communication Styles
Aggressive Behavior
BOX 15.6: Applications: Sexual Harassment and Dating Violence
Review

CHAPTER 16: Conclusions
Theme 1: Nature and Nurture: All Interactions, All the Time
Nature and Nurture Begin Interacting Before Birth
Infants’ Nature Elicits Nurture
Timing Matters
Nature Does Not Reveal Itself All at Once
Everything Influences Everything
Theme 2: Children Play Active Roles in Their Own Development
Self-Initiated Activity
Active Interpretation of Experience
Self-Regulation
Eliciting Reactions from Other People
Theme 3: Development Is Both Continuous and Discontinuous
Continuity/Discontinuity of Individual Differences
Continuity/Discontinuity of Overall Development: The Question of Stages
Theme 4: Mechanisms of Developmental Change
Biological Change Mechanisms
Behavioral Change Mechanisms
Cognitive Change Mechanisms
Change Mechanisms Work Together
Theme 5: The Sociocultural Context Shapes Development
Growing Up in Societies with Different Practices and Values
Growing Up in Different Times and Places
Growing Up in Different Circumstances Within a Society
Theme 6: Individual Differences
Breadth of Individual Differences at a Given Time
Stability Over Time
Predicting Future Individual Differences on Other Dimensions
Determinants of Individual Differences
Theme 7: Child-Development Research Can Improve Children’s Lives
Implications for Parenting
Implications for Education
Implications for Helping Children at Risk
Improving Social Policy

Glossary
References
Name Index
Subject Index

2015-05-01T18:23:54+0000
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