Encyclopedia of Infant and Early Childhood Development, vol 2 (Academic Press, 2008) pdf

  

EDITORS-IN-CHIEF

  Marshall M. Haith received his M.A. and Ph.D. degrees from U.C.L.A. and then carried out postdoctoral work at Yale University from 1964–1966. He served as Assistant Professor and Lecturer at Harvard University from 1966–1972 and then moved to the University of Denver as Professor of Psychology, where he has conducted research on infant and children’s perception and cognition, funded by NIH, NIMH, NSF, The MacArthur Foundation, The March of Dimes, and The Grant Foundation. He has been Head of the Developmental Area, Chair of Psychology, and Director of University Research at the University of Denver and is currently John Evans Professor Emeritus of Psychology and Clinical Professor of Psychiatry at the University of Colorado Health Sciences Center.

  Dr. Haith has served as consultant for Children’s Television Workshop (Sesame Street), Bilingual Children’s Television, Time-Life, and several other organizations. He has received several personal awards, including University Lecturer and the John Evans Professor Award from the University of Denver, a Guggenheim Fellowship for serving as Visiting Professor at the University of Paris and University of Geneva, a NSF fellowship at the Center for Advanced Study in the Behavioral Sciences (Stanford), the G. Stanley Hall Award from the American Psychological Association, a Research Scientist Award from NIH (17 years), and the Distinguished Scientific Contribution Award from the Society for Research in Child Development.

  Janette B. Benson earned graduate degrees at Clark University in Worcester, MA in 1980 and 1983. She came to the University of Denver in 1983 as an institutional postdoctoral fellow and then was awarded an individual NRSA postdoctoral fellowship. She has received research funding form federal (NICHD; NSF) and private (March of Dimes, MacArthur Foundation) grants, leading initially to a research Assistant Professor position and then an Assistant Professorship in Psychology at the University of Denver in 1987, where she remains today as Associate Professor of Psychology and as Director of the undergraduate Psychology program and Area Head of the Developmental Ph.D. program and Director of University Assessment. Dr. Benson has received various awards for her scholarship and teaching, including the 1993 United Methodist Church University Teacher Scholar of the Year and in 2000 the CASE Colorado Professor of the Year. Dr. Benson was selected by the American Psychological Association as the 1995–1996 Esther Katz Rosen endowed Child Policy Fellow and AAAS Congressional Science Fellow, spending a year in the United States Senate working on Child and Education Policy. In 1999, Dr. Benson was selected as a Carnegie Scholar and attended two summer institutes sponsored by the Carnegie Foundation program for the Advancement for the Scholarship of Teaching and Learning in Palo Alto, CA. In 2001, Dr. Benson was awarded a Susan and Donald Sturm Professorship for Excellence in Teaching. Dr. Benson has authored and co-authored numerous chapters and research articles on infant and early childhood development in addition to co-editing two books.

EDITORIAL BOARD

  Richard Aslin is the William R. Kenan Professor of Brain and Cognitive Sciences at the University of Rochester and is also the director of the Rochester Center for Brain Imaging. His research has been directed to basic aspects of sensory and perceptual development in the visual and speech domains, but more recently has focused on mechanisms of statistical learning in vision and language and the underlying brain mechanisms that support it. He has published over 100 journal articles and book chapters and his research has been supported by NIH, NSF, ONR, and the Packard and McDonnell Foundations. In addition to service on grant review panels at NIH and NSF, he is currently the editor of the journal Infancy. In 1981 he received the Boyd R. McCandless award from APA (Division 7), in 1982 the Early Career award from APA (developmental), in 1988 a fellowship from the John Simon Guggenheim foundation, and in 2006 was elected to the American Academy of Arts and Sciences.

  Warren O. Eaton is Professor of Psychology at the University of Manitoba in Winnipeg, Canada, where he has spent his entire academic career. He is a fellow of the Canadian Psychological Association, and has served as the editor of one of its journals, the Canadian Journal of Behavioural Science. His current research interests center on child-to-child variation in developmental timing and how such variation may contribute to later outcomes.

  Robert Newcomb Emde is Professor of Psychiatry, Emeritus, at the University of Colorado School of Medicine. His research over the years has focused on early socio-emotional development, infant mental health and preventive interventions in early childhood. He is currently Honorary President of the World Association of Infant Mental Health and serves on the Board of Directors of Zero To Three.

  Hill Goldsmith is Fluno Bascom Professor and Leona Tyler Professor of Psychology at the University of Wisconsin–Madison. He works closely with Wisconsin faculty in the Center for Affective Science, and he is the coordinator of the Social and Affective Processes Group at the Waisman Center on Mental Retardation and Human Development. Among other honors, Goldsmith has received an National Institute of Mental Health MERIT award, a Research Career Development Award from the National Institute of Child Health and Human Development, the James Shields Memorial Award for Twin Research from the Behavior Genetics Association, and various awards from his university. He is a Fellow of AAAS and a Charter Fellow of the Association for Psychological Science. Goldsmith has also served the National Institutes of Health in several capacities. His editorial duties have included a term as Associate Editor of one journal and membership on the editorial boards of the five most important journals in his field. His administrative duties have included service as department chair at the University of Wisconsin.

  Richard B. Johnston Jr. is Professor of Pediatrics and Associate Dean for Research Development at the University of Colorado School of Medicine and Associate Executive Vice President of Academic Affairs at the National Jewish Medical & Research Center. He is the former President of the American Pediatric Society and former Chairman of the International Pediatric Research Foundation. He is board certified in pediatrics and infectious disease. He has previously acted as the Chief of Immunology in the Department of Pediatrics at Yale University School of Medicine, been the Medical Director of the March of Dimes Birth Defects Foundation, Physician-in-Chief at the Children’s Hospital of Philadelphia and Chair of the Department of Pediatrics at the University Pennsylvania School of Medicine. He is editor of ‘‘Current Opinion in Pediatrics’’ and has formerly served on the editorial board for a host of journals in pediatrics and infectious disease. He has published over 80 scientific articles and reviews and has been cited over 200 times for his articles on tissue injury in inflammation, granulomatous disease, and his New England Journal of Medicine article on immunology, monocytes, and macrophages. viii Editorial board

  Jerome Kagan is a Daniel and Amy Starch Professor of Psychology at Harvard University. Dr. Kagan has won numerous awards, including the Hofheimer Prize of the American Psychiatric Association and the G. Stanley Hall Award of the American Psychological Association. He has served on numerous committees of the National Academy of Sciences, The National Institute of Mental Health, the President’s Science Advisory Committee and the Social Science Research Council. Dr. Kagan is on the editorial board of the journals Child Development and Developmental Psychology, and is active in numerous professional organizations. Dr. Kagan’s many writings include Understanding Children: Behavior, Motives, and Thought, Growth of the Child, The Second Year: The Emergence of Self-Awareness, and a number of cross-cultural studies of child development. He has also coauthored a widely used introductory psychology text. Professor Kagan’s research, on the cognitive and emotional development of a child during the first decade of life, focuses on the origins of temperament. He has tracked the development of inhibited and uninhibited children from infancy to adolescence. Kagan’s research indicates that shyness and other temperamental differences in adults and children have both environmental and genetic influences.

  Rachel Keen (formerly Rachel Keen Clifton) is a professor at the University of Virginia. Her research expertise is in perceptual-motor and cognitive development in infants. She held a Research Scientist Award from the National Institute of Mental Health from 1981 to 2001, and currently has a MERIT award from the National Institute of Child Health and Human Development. She has served as Associate Editor of Child Development (1977–1979), Psychophysiology (1972–1975), and as Editor of SRCD Monographs (1993–1999). She was President of the International Society on Infant Studies from 1998–2000. She received the Distinguished Scientific Contribution Award from the Society for Research in Child Development in 2005 and was elected to the American Academy of Arts and Science in 2006. Ellen M. Markman is the Lewis M. Terman Professor of Psychology at Stanford University. Professor Markman was chair of the Department of Psychology from 1994–1997 and served as Cognizant Dean for the Social Sciences from 1998–2000. In 2003 she was elected to the American Academy of Arts and Sciences and in 2004 she was awarded the American Psychological Association’s Mentoring Award. Professor Markman’s research has covered a range of issues in cognitive development including work on comprehension monitoring, logical reasoning and early theory of mind development. Much of her work has addressed questions of the relationship between language and thought in children focusing on categorization, inductive reasoning, and word learning.

  Yuko Munakata is Professor of Psychology at the University of Colorado, Boulder. Her research investigates the origins of knowledge and mechanisms of change, through a combination of behavioral, computational, and neuroscientific methods. She has advanced these issues and the use of converging methods through her scholarly articles and chapters, as well as through her books, special journal issues, and conferences. She is a recipient of the Boyd McCandless Award from the American Psychological Association, and was an Associate Editor of Psychological Review, the field’s premier theoretical journal.

  Arnold J. Sameroff, is Professor of Psychology at the University of Michigan where he is also Director of the Development and Mental Health Research Program. His primary research interests are in understanding how family and community factors impact the development of children, especially those at risk for mental illness or educational failure. He has published 10 books and over 150 research articles including the Handbook of Developmental Psychopathology, The Five to Seven Year Shift: The Age of Reason and Responsibility, and the forthcoming Transactional Processes in Development.

  Among his honors are the Distinguished Scientific Contributions Award from the Society for Research in Child Development and the G. Stanley Hall Award from the American Psychological Association. Currently he is President of the Society for Research in Child Development and serves on the executive Committee of the International Society for the Study of Behavioral Development.

  

FOREWORD

  This is an impressive collection of what we have learned about infant and child behavior by the researchers who have contributed to this knowledge. Research on infant development has dramatically changed our perceptions of the infant and young child. This wonderful resource brings together like a mosaic all that we have learned about the infant and child’s behavior. In the 1950s, it was believed that newborn babies couldn’t see or hear. Infants were seen as lumps of clay that were molded by their experience with parents, and as a result, parents took all the credit or blame for how their offspring turned out. Now we know differently.

  The infant contributes to the process of attaching to his/her parents, toward shaping their image of him, toward shaping the family as a system, and toward shaping the culture around him. Even before birth, the fetus is influenced by the intrauterine environment as well as genetics. His behavior at birth shapes the parent’s nurturing to him, from which nature and nurture interact in complex ways to shape the child.

  Geneticists are now challenged to couch their findings in ways that acknowledge the complexity of the interrelation between nature and nurture. The cognitivists, inheritors of Piaget, must now recognize that cognitive development is encased in emotional development, and fueled by passionately attached parents. As we move into the era of brain research, the map of infant and child behavior laid out in these volumes will challenge researchers to better understand the brain, as the basis for the complex behaviors documented here. No more a lump of clay, we now recognize the child as a major contributor to his own brain’s development.

  This wonderful reference will be a valuable resource for all of those interested in child development, be they students, researchers, clinicians, or passionate parents.

  T. Berry Brazelton, M.D. Professor of Pediatrics, Emeritus Harvard Medical School

  Creator, Neonatal Behavioral Assessment Scale (NBAS) Founder, Brazelton Touchpoints Center

  

PREFACE

  Encyclopedias are wonderful resources. Where else can you find, in one place, coverage of such a broad range of topics, each pursued in depth, for a particular field such as human development in the first three years of life? Textbooks have their place but only whet one’s appetite for particular topics for the serious reader. Journal articles are the lifeblood of science, but are aimed only to researchers in specialized fields and often only address one aspect of an issue. Encyclopedias fill the gap.

  In this encyclopedia readers will find overviews and summaries of current knowledge about early human development from almost every perspective imaginable. For much of human history, interest in early development was the province of pedagogy, medicine, and philosophy. Times have changed. Our culling of potential topics for inclusion in this work from textbooks, journals, specialty books, and other sources brought home the realization that early human development is now of central interest for a broad array of the social and biological sciences, medicine, and even the humanities. Although the ‘center of gravity’ of these volumes is psychology and its disciplines (sensation, perception, action, cognition, language, personality, social, clinical), the fields of embryology, immunology, genetics, psychiatry, anthropol- ogy, kinesiology, pediatrics, nutrition, education, neuroscience, toxicology and health science also have their say as well as the disciplines of parenting, art, music, philosophy, public policy, and more.

  Quality was a key focus for us and the publisher in our attempts to bring forth the authoritative work in the field. We started with an Editorial Advisory Board consisting of major contributors to the field of human development – editors of major journals, presidents of our professional societies, authors of highly visible books and journal articles. The Board nominated experts in topic areas, many of them pioneers and leaders in their fields, whom we were successful in recruiting partly as a consequence of Board members’ reputations for leadership and excellence. The result is articles of exceptional quality, written to be accessible to a broad readership, that are current, imaginative and highly readable.

  Interest in and opinion about early human development is woven through human history. One can find pronounce- ments about the import of breast feeding (usually made by men), for example, at least as far back as the Greek and Roman eras, repeated through the ages to the current day. Even earlier, the Bible provided advice about nutrition during pregnancy and rearing practices. But the science of human development can be traced back little more than 100 years, and one can not help but be impressed by the methodologies and technology that are documented in these volumes for learning about infants and toddlers – including methods for studying the role of genetics, the growth of the brain, what infants know about their world, and much more. Scientific advances lean heavily on methods and technology, and few areas have matched the growth of knowledge about human development over the last few decades. The reader will be introduced not only to current knowledge in this field but also to how that knowledge is acquired and the promise of these methods and technology for future discoveries.

  CONTENTS

  Several strands run through this work. Of course, the nature-nurture debate is one, but no one seriously stands at one or the other end of this controversy any more. Although advances in genetics and behavior genetics have been breathtaking, even the genetics work has documented the role of environment in development and, as Brazelton notes in his foreword, researchers acknowledge that experience can change the wiring of the brain as well as how actively the genes are expressed. There is increasing appreciation that the child develops in a transactional context, with the child’s effect on the parents and others playing no small role in his or her own development.

  There has been increasing interest in brain development, partly fostered by the decade of the Brain in the 1990s, as we xii Preface

  intelligence. The ‘brainy baby’ movement has rightly aroused interest in infants’ surprising capabilities, but the full picture of how abilities develop is being fleshed out as researchers learn as much about what infants can not do, as they learn about what infants can do. Parents wait for verifiable information about how advances may promote effective parenting.

  An increasing appreciation that development begins in the womb rather than at birth has taken place both in the fields of psychology and medicine. Prenatal and newborn screening tools are now available that identify infants at genetic or developmental risk. In some cases remedial steps can be taken to foster optimal development; in others ethical issues may be involved when it is discovered that a fetus will face life challenges if brought to term. These advances raise issues that currently divide much of public opinion. Technological progress in the field of human development, as in other domains, sometimes makes options available that create as much dilemma as opportunity.

  As globalization increases and with more access to electronic communication, we become ever more aware of circumstances around the world that affect early human development and the fate of parents. We encouraged authors to include international information wherever possible. Discussion of international trends in such areas as infant mortality, disease, nutrition, obesity, and health care are no less than riveting and often heartbreaking. There is so much more to do.

  The central focus of the articles is on typical development. However, considerable attention is also paid to psychological and medical pathology in our attempt to provide readers with a complete picture of the state of knowledge about the field. We also asked authors to tell a complete story in their articles, assuming that readers will come to this work with a particular topic in mind, rather than reading the Encyclopedia whole or many articles at one time. As a result, there is some overlap between articles at the edges; one can think of partly overlapping circles of content, which was a design principle inasmuch as nature does not neatly carve topics in human development into discrete slices for our convenience. At the end of each article, readers will find suggestions for further readings that will permit them to take off in one neighboring direction or another, as well as web sites where they can garner additional information of interest.

  AUDIENCE

  Articles have been prepared for a broad readership, including advanced undergraduates, graduate students, professionals in allied fields, parents, and even researchers for their own disciplines. We plan to use several of these articles as readings for our own seminars.

  A project of this scale involves many actors. We are very appreciative for the advice and review efforts of members of the Editorial Advisory Board as well as the efforts of our authors to abide by the guidelines that we set out for them. Nikki Levy, the publisher at Elsevier for this work, has been a constant source of wise advice, consolation and balance. Her vision and encouragement made this project possible. Barbara Makinster, also from Elsevier, provided many valuable suggestions for us. Finally, the Production team in England played a central role in communicating with authors and helping to keep the records straight. It is difficult to communicate all the complexities of a project this vast; let us just say that we are thankful for the resource base that Elsevier provided. Finally, we thank our families and colleagues for their patience over the past few years, and we promise to ban the words ‘‘encyclopedia project’’ from our vocabulary, for at least a while.

  Marshall M. Haith and Janette B. Benson

  Department of Psychology, University of Denver Denver, Colorado, USA

PERMISSION ACKNOWLEDGMENTS

  The following material is reproduced with kind permission of Oxford University Press Ltd Figure 1 of Self-Regulatory Processes The following material is reproduced with kind permission of AAAS Figure 1 of Maternal Age and Pregnancy Figures 1a, 1b and 1c of Perception and Action The following material is reproduced with kind permission of Nature Publishing Group Figure 2 of Self-Regulatory Processes The following material is reproduced with kind permission of Taylor & Francis Ltd Figure 4b of Visual Perception

  G Gender: Awareness, Identity, and Stereotyping K M Zosuls, L E Lurye, and D N Ruble, New York University, New York, NY, USA ã 2008 Elsevier Inc. All rights reserved.

  Glossary Collective identity – Refers to the self as a member of a collective group, such as gender or race. See also social identity. Gender awareness – Although the term ‘awareness’ is often used more generally, in this article, this term specifically refers to children’s ability to distinguish the sexes.

  Gender constancy – Proposed by Lawrence Kohlberg to refer to children’s understanding that gender is not changeable. The development of gender constancy includes three stages: (1) accurate identification of sex category membership for oneself and others (basic gender identity); (2) stability of sex category membership over time (gender stability); and (3) consistency of sex category membership across superficial transformations in appearance or context (gender consistency). Gender development – Refers to the processes involved in the development of the components of gender, including concepts and beliefs about gender, gender identity, or self-perception as a member of a gender group, gender-related preferences, and gender-related behaviors. Developmental processes are generally described as cognitive, socialization, or biological. Habituation methodologies – A type of looking time method in which infants are first presented with a stimulus until they lose interest in it or ‘habituate’ to it and are then presented with a pair of stimuli. The pair of stimuli contains one stimulus similar to and one stimulus different from the habituation stimulus. The time infants spend looking at each stimulus is measured. These studies presume that differences in looking time between the familiar and novel stimulus represent an awareness of differences between the two stimuli.

  Looking time methods (preferential looking methods) – Methods used in studies with infants who are still too young to effectively express their knowledge verbally and who have other infancy-related performance limitations (e.g., cognitive, motor) that do not allow for the use of methods in which children have to perform tasks or answer questions. These methods typically involve showing infants pairs of stimuli and measuring the time that infants spend looking at each one of the stimuli. Sequential touching paradigm – An unstructured task in which children are given a set of objects from two different categories (e.g., male and female dolls) and categorization is inferred if a child touches objects from a single category in succession more than would be expected from chance. It is thought that such spontaneous behaviors indicate attention to categorical contrasts. Social identity – Although defined in various ways, key elements include: (1) refers to aspects of the self-concept that are defined in terms of or in relation to other people and groups, (2) socially constructed and interpersonally significant categories, and (3) certain values and emotional significance are attached to these role or category memberships. Social identity is a broader concept than collective identity in that it can refer to the self as fulfilling a role or the self as a member of a collective group (i.e., collective identity). Violation of expectancy paradigm – A looking time method in which children’s looking times are measured in response to mismatched stimuli or impossible events compared to properly matched or possible events. Longer looking times to mismatched stimuli/impossible events are thought to indicate that an event is perceived as novel, surprising, or incongruous, suggesting that it is unexpected.

2 Gender: Awareness, Identity, and Stereotyping

  Introduction

  Psychologists have long been intrigued with the processes involved in the development of the gendered self. Chil- dren grow up in a world ubiquitous with social categories and by the time that they are toddlers, they learn to label others and themselves according to their gender. By the time they enter elementary school, children know a wide range of gender stereotypes. Children also develop sex-typed behaviors at an early age, and such behaviors tend to increase during early childhood. Because the development of gender-related knowledge and sex-typed behavior appear to coincide, the relationship between these two facets of gender development remains an area of active study. During early childhood, it has been sug- gested by some researchers that attainment of gender identity has important implications for the adoption and maintenance of sex-typed behavior. However, as children become older, develop more complex identities, and become embedded in more complex social worlds, it is believed that the influence of gender identity may expand and become important for self-evaluation and psychological wellbeing. Although the role of biological factors will be discussed, the focus of this article is on gender identity as a social construct and the processes involved in children s developing understanding of themselves as girls or boys. In this article, we focus on children s emerging understanding of three major aspects of gender development identity, awareness, and stereo- types from the perspective that gender development is best understood as resulting from a combination of social, biological, and cognitive factors. Central to our point of view is the idea that children play an active role in their gender development and continually construct and revise their understanding of what it means to be a boy or girl.

  Gender Knowledge in Infants and Toddlers

  In this section, we examine the first indications of children s awareness of gender category distinctions. These signs involve both simple perceptual distinctions in infancy and more advanced abilities of toddlers to categorize themselves and others as boys and girls and show evidence of gender stereotype knowledge.

  Perceptual Distinction Evidence from a number of studies using habituation and preferential looking methodologies supports the idea that infants are able to perceptually discriminate between men and women well before gender differen- tiated behavior is observed. Infants as young as features and 6-month-old infants can distinguish voices of women and men. By 9 months of age, most infants are able to discriminate between pictures of men and women and use hair and clothing information as gender cues. By 12 months of age, infants also demonstrate inter- modal gender knowledge; that is, infants are able to recog- nize the associations between male and female faces voices, showing that they can form associations across sensory modalities. In a study by Diane Poulin-Dubois and colleagues that investigated this ability, 1-, 12-month-old infants were presented with pairs of male and female photographs and either a male or a femal voice saying, Hi baby! Look at me! Here I am. Look me! The oldest group of infants was most consistent looking for a longer period of time when the pictu matched the voice, especially in the case of female f This greater ability to match female faces and voices might be due to infants greater amount of exposure to, and therefore expertise in processing, female compared male faces and voices. Taken together, these studies gest that by the time children reach their first bir they have in place the perceptual categories of gender Active Categorization The ability to perceptually distinguish males from femal sets the stage for the development of more advanced knowledge about gender. In the second year of life, chil- dren begin to categorize people as men and women and boys and girls spontaneously in their everyday lives. other words, in addition to recognizing that males females look different, children use this knowledge actively categorize people as males and females. A stud using a sequential touching paradigm in which observ coded the order in which infants touched a set of male and female dolls found that although at 18 months of age some children appeared to categorize males and females, categorization increased sharply between and 22 months of age. Although the authors of this stud interpreted this behavior to indicate that in the months before children turn 2 years, they increasingly atte and use gender categories, this conclusion is open interpretation.

  Most studies investigating children s ability to cate rize males and females have used either nonverbal verbal gender-labeling paradigms. Studies using dif procedures have led to different conclusions about w children are first able to actively categorize males females. Studies assessing gender labeling in very y children have most typically used nonverbal measur that involve pointing to a picture of a male or female response to an experimenter s question, or sorting pictures into boxes designated for either males or females Most of these studies have concluded that children are about 28 30 months old. Nevertheless, research using different procedures, particularly preferential looking techniques and measures of children s vocabularies, sug- gests a different conclusion. For example, our own research has found that while at 17 months of age only a minority of children have spontaneously (i.e., without prompts or cues) and flexibly (i.e., across contexts) used a gender label, by 21 22 months of age, a majority of children have produced at least one gender label, with most children having produced multiple labels. Other studies examining children s word usage have found that children begin to overgeneralize the labels mommy and daddy to other females and males starting at about 18 months of age, and that by 24 months of age, both boys and girls appear to have learned more same-gender-typed words (e.g., beads, fire truck, girl, boy) than other-gender- typed words. These studies all suggest that although young children might not have a sophisticated understanding of gender, by the age of 2 years, children have some under- standing of gender as a social category and have begun to divide their social worlds into males and females.

  Aside from categorizing other males and females, chil- dren also learn to categorize themselves into a gender group. Studies assessing children s self-labeling have typ- ically used the same nonverbal pointing and sorting pro- cedures just discussed and results from these studies have led to similar conclusions for self-labeling. That is, chil- dren appear to reliably self-label when they are approxi- mately 28 30 months old. However, some evidence suggests that children are able to verbally self-label by the time that they are 2 years old. Such self-labeling is of particular interest, because it appears to represent a prim- itive or basic gender identity. In other words, once chil- dren achieve a basic gender identity not only do they recognize that there are two gender groups, but also that they are a member of one of them. This understanding is thought by some researchers to have motivational signifi- cance for subsequent gender development, as discussed in a later section.

  Gender Stereotype Knowledge Given children s increased understanding of gender dur- ing the second year, it is not surprising that studies using a variety of paradigms suggest that infants knowledge of attributes stereotypically associated with gender cate- gories increases substantially during the second year. For example, in a study by Lisa Serbin and colleagues that used an adaptation of the preferential looking paradigm, researchers found that at 18 and 24 months of age, girls were able to match male and female faces and voices to gender-stereotyped toys (i.e., dolls and vehicles). Another looking time study by some of the same researchers found that both boys and girls made associations between at 18 and 24 months of age, although these associations were only significant for masculine items. Interestin these associations were found for both conventionally stereotyped items, such as a fire hat and a tiara, metaphorically stereotyped items, such as a fir tree a heart. The metaphoric associations are particular interesting, as they suggest that gender knowledge can be acquired not only through direct teaching and obser- vation of certain items, but also through inferring ass tions between gender and certain physical (e.g., angularity, size) and more abstract and internal quali (e.g., gentleness, love). Nevertheless, as with some other looking-time studies we have described, these inter- pretations are open to debate. For instance, it is not why associations were only significant for male items why items such as hearts, which commonly adorn girls clothing and accessories, would have been considered metaphoric rather than conventional objects commonly associated with females. There are myriad challenges involved with studying infants because of their limited language, cognitive, and motor skills; thus, it is the researchers to find creative ways of studying infant knowledge. As with any field of research, it is necessary to replicate findings using multiple research methods.

  Gender Knowledge in Early Childhood

  Even though 2 3-year-olds are able to categorize males and females, their understanding of gender is still r mentary. From the ages of approximately 3 6 years, chil- dren develop a better understanding of gender as an unchangeable, enduring social category and their knowl- edge of gender stereotypes increases. At the same time, children are likely to develop a more complex sense of themselves as members of a gender category.

  Gender Constancy According to Kohlberg, achieving gender constancy is critical milestone in gender development. The idea gender constancy is analogous to Piaget s concept of con- servation of physical properties in that gender constanc refers to understanding that gender is an invariant human property that is stable across time and superficial changes in appearance. Kohlberg outlined three developmental stages that children achieve in order to have gender con- stancy. The first stage, gender identity, is children awareness that they are either boys or girls. The secon stage, gender stability, refers to the recognition that der identity does not change over time. The third stage gender consistency, represents the achievement of gender constancy and refers to the understanding that gender is not changed by transformations in gender-typed

  Gender: Awareness, Identity, and Stereotyping

  3

4 Gender: Awareness, Identity, and Stereotyping

  children achieve gender constancy, at about age 6 7 years, they understand that they are either a girl or a boy (gender identity), that they will grow up to be an adult of the same gender (i.e., a woman or a man) (gender stability), and that their gender will not be changed if they do things such as put on opposite sex-typed clothes (gender consistency). Numerous studies, including cross- cultural evidence, have confirmed the order of the stages, though the exact ages at which the highest level is reached vary greatly depending on methodology.

  Rigidity and Flexibility of Identity As children grow older and develop more sophisticated knowledge about gender, their gender-related self- concepts and gender-related behaviors are also likely to be impacted. In fact, researchers have found evidence to support the idea that children progress through a devel- opmental pattern in their gender concepts that can be described as a sequence of three phases: (1) beginning awareness (construction/information processing), (2) rigid- ity (consolidation/schema confirmation), and (3) flexibility (integration/schema development). While these stages are characterized by a quantitative increase in gender knowl- edge, they are also characterized by a qualitative change in knowledge and possibly behavior, particularly in terms of how rigidly or flexibly children classify attributes and behaviors as appropriate for both sexes. For instance, a child who has a rigid concept of femininity might think that only girls can wear pink and she might also become ada- mant about wearing pink dresses everyday. An older child with a more flexible concept of femininity would be more likely to think that both boys and girls can wear pink; thus, this knowledge might be associated with more flexible behaviors.

  It appears that children tend to enter a short-lived period of rigidity in terms of gender stereotype knowl- edge between the ages of about 4 and 6 years, followed by increasing levels of flexibility over the next several years. The increase of flexibility beginning at about age 7 or 8 years is consistent with other areas of cognitive and social cognitive development, such as higher classification abilities, a full understanding of gender constancy, and a better understanding of people in terms of psychological traits. For instance, research has shown that the ability to understand that the same object or person can belong to two categories simultaneously is related to more egalitar- ian responding on gender stereotyping measures. Both multiple classification ability and full gender constancy understanding emerge in the early elementary school years at around the time when children become more flexible. Also, prior to the age of 7 8 years, children s self and other descriptions typically refer to concrete, observ- able characteristics and social relationships (e.g., I am a 8 years, children s self and other descriptions consist statements that reflect a view of people as having more abstract, psychological characteristics that direct These descriptions also become more evaluative in ter of comparisons with others. Thus, as children become older, their gender identities may take on meaning bey superficial, physical characteristics and become imbued with meaning linked with stable psychological characte istics. In general, more research is needed to investig the concepts of rigidity and flexibility with respec ways in which children think and feel about themselves girls or boys, both in terms of normative developmen patterns and individual differences.

  Although general cognitive and social cognitive factor might play an important role in the development of iden- tification with a gender category, it is important remember that the social context is also likely to pla important role in the timing of various phases of gender development and the degree to which certain phenomena, such as gender rigidity, are observed. For instance, children might be more likely to develop a basic gender identity at an earlier age and show an early and inten degree of gender rigidity if they grow up in a highly sex-typed environment with parents who adhere to tra- ditional gender roles and attitudes.

  Multidimensionality of Identity The bulk of research on children s early gender identity has focused on Kohlberg s stages. However, more recently researchers have begun to investigate aspects other knowledge about one s own gender (i.e., gender identity stability, and consistency) and turned to focus on dren s self-perceptions of similarity to other memb one s gender group and to the evaluative meaning of gender identity. Within the gender identity and raci ethnic identity literatures, theorists have begun to tigate identity as a multidimensional construct, dimensions that tap into a range of factors having to with an individual s unique, subjective experience member of a social category. David Perry and colleagu have proposed a multidimensional model of gender iden- tity that focuses on children s feelings about themsel girls or boys. In addition, Robert Sellers and colleagu developed a multidimensional model of racial identity study African American identity, and researchers inter- ested in other social and collective identities, su gender, have begun to adapt this model to their ow research in order to investigate identity with greater depth and precision. Although these models are mos applicable to middle childhood and beyond, little known about how and when these other aspects of identity develop. As a result, the gender development literatu lacks a certain degree of continuity in terms of identity following two sections will review these multidimensional models in light of what is known from the existing litera- ture to suggest possible developmental patterns. Perry s model As will be discussed in the following section, by the time that children are in elementary school, they know a broad range of gender stereotypes. Therefore, starting at a young age, children can assess the degree to which they are typical of their gender using a number of different dimensions (e.g., toy and activity preferences, playmate preferences, academic and professional aspirations). How do feelings of being typical for one s gender interact with factors such as pressure to conform to gender stereo- types and general feelings about one s gender group, to affect adjustment outcomes, such as self-worth and self-perceived social competence?

  In order to address this question, Perry and colleagues proposed a multidimensional model of gender identity that, in addition to knowledge of gender identity, includes three components: (1) feelings of psychological typicality or compatibility with one s gender; (2) feelings of pressure from parents, peers, and self for conformity to gender stereotypes; and (3) intergroup gender attitudes (i.e., the degree to which one feel s one s own gender group is superior). Their research has found that while perceived gender typicality and contentedness is positively related to psychological adjustment, the felt pressure to conform to gender stereotypes is negatively related to adjustment. These dimensions have primarily been studied among children in middle childhood through adolescence; there- fore the developmental course of these dimensions is unclear.

  It has been suggested that while felt pressure to con- form might develop in preschool, feelings of perceived typicality might not emerge until children are slightly older and engage in social comparison. Social comparison processes serve to help children self socialize (i.e., learn and adopt the social rules of a given culture or environ- ment) and are oriented toward (1) determining how one is supposed to behave and (2) evaluating how good one is at a certain behavior. Although research on social compari- son has typically focused on the academic domain, find- ings might nevertheless help to illuminate processes involved in gender self-socialization. After all, children certainly engage in social comparison to learn a host of social norms and behaviors, including those related to gender. The degree to which children perceive that they meet standards for appropriate behavior for their gender group is likely to affect feelings of typicality.

  There is considerable evidence showing that the seek- ing out and use of social comparison information for self- evaluations of competence increases during the early years of elementary school. However, it is not until about information for competence-related self-assessments These findings also suggest that beginning at about age 7 years, pressures to conform might take on new meaning and importance to the self, consequently children might feel more pressure to conform to gender stereotypes. It also possible that these processes might emerge slightly earlier in the case of gender self-socialization, giv children possess most of the prerequisite cognitive skills (e.g., recognition that people have different characte and capacities, recognition of the relative characte or skills of different people), strategies (e.g., choosing relevant others to compare oneself to), and motivation necessary for social comparison during the preschool years. However, the actual use of social comparison info mation might depend on other factors, such as the concreteness of the category, the stability of relevant acteristics, perceived relevance of information to one stable characteristics, and social pressures. While a child might not begin to think of smartness or intellig as a stable trait until age 7 or 8 years, he or she migh recognize the stability of gender slightly earlier, a age 6 years, when he or she achieves gender constancy and sees gender as an enduring characteristic. In fact, res from the gender constancy literature supports the idea social comparison processes are associated with high le of gender constancy. In a study by Diane Ruble and collea- gues, 4 6-year-old children divided into high- and lo gender constancy groups watched a commercial for a gender-neutral toy that had either two boys or two girls playing with the toy or did not see a commercial (contr group). Only high-constancy children who saw opposite- sex children playing with the toy avoided spending tim with the toy in a subsequent play session and expressed that the toy would be more appropriate for an opposite sex child. Furthermore, since gender is so salient early i children might also be more motivated to use social com- parison information at earlier ages in their gender-rela self-socialization as a way to learn how to behave lik girl or like a boy . Thus, it remains to be investig when gender-related social comparison processes and feelings about gender typicality emerge and whether these two processes are related.