Sex differences in response to children's toys in nonhuman primates (Cercopithecus aethiops sabaeus)

Sex differences in children’s toy preferences are thought by many to arise from gender socialization. However, evidence from patients with endocrine disorders suggests that biological factors during early development (e.g., levels of androgens) are influential. In this study, we found that vervet monkeys (Cercopithecus aethiops sabaeus) show sex differences in toy preferences similar to those documented previously in children. The percent of contact time with toys typically preferred by boys (a car and a ball) was greater in male vervets (n=33) than in female vervets (n=30) (P<.05), whereas the percent of contact time with toys typically preferred by girls (a doll and a pot) was greater in female vervets than in male vervets (P<.01). In contrast, contact time with toys preferred equally by boys and girls (a picture book and a stuffed dog) was comparable in male and female vervets. The results suggest that sexually differentiated object preferences arose early in human evolution, prior to the emergence of a distinct hominid lineage. This implies that sexually dimorphic preferences for features (e.g., color, shape, movement) may have evolved from differential selection pressures based on the different behavioral roles of males and females, and that evolved object feature preferences may contribute to present day sexually dimorphic toy preferences in children. D 2002 Elsevier Science Inc. All rights reserved.

[1]  Sheri A. Berenbaum,et al.  Early Androgens Are Related to Childhood Sex-Typed Toy Preferences , 1992 .

[2]  Mike Meaney,et al.  Infant carrying by nulliparous female vervet monkeys (Cercopithecus aethiops). , 1990 .

[3]  James C. Raymondo,et al.  Statistical Analysis in the Behavioral Sciences , 1998 .

[4]  L. Cosmides,et al.  The Adapted Mind , 1992 .

[5]  Anke A. Ehrhardt,et al.  Fetal androgens, human central nervous system differentiation, and behavior sex differences. , 1974 .

[6]  P. White,et al.  Congenital adrenal hyperplasia (2). , 1987, The New England journal of medicine.

[7]  E. Maccoby,et al.  Gender as a social category. , 1988 .

[8]  M. Hines,et al.  Androgen and the development of human sex-typical behavior: rough-and-tumble play and sex of preferred playmates in children with congenital adrenal hyperplasia (CAH). , 1994, Child development.

[9]  B. Fagot,et al.  Observations of parent reactions to sex-stereotyped behaviors: age and sex effects. , 1991, Child development.

[10]  M. Hines,et al.  Gender labels and play styles: their relative contribution to children's selection of playmates. , 1994, Child development.

[11]  N. Dominy,et al.  Ecological importance of trichromatic vision to primates , 2001, Nature.

[12]  J. Mollon,et al.  Fruits, foliage and the evolution of primate colour vision. , 2001, Philosophical transactions of the Royal Society of London. Series B, Biological sciences.

[13]  O. Arisaka,et al.  Sex Differences in Children's Free Drawings: A Study on Girls with Congenital Adrenal Hyperplasia , 2001, Hormones and Behavior.

[14]  G. Alexander.  An Evolutionary Perspective of Sex-Typed Toy Preferences: Pink, Blue, and the Brain , 2003, Archives of sexual behavior.

[15]  J. DiPietro,et al.  Rough and tumble play: A function of gender. , 1981 .

[16]  Leslie G. Ungerleider,et al.  Mechanisms of visual attention in the human cortex. , 2000, Annual review of neuroscience.

[17]  S. Gaulin,et al.  Superior spatial memory of women: Stronger evidence for the gathering hypothesis , 1997 .

[18]  J. Lancaster.  Play-mothering: the relations between juvenile females and young infants among free-ranging vervet monkeys (Cercopithecus aethiops). , 1971, Folia primatologica; international journal of primatology.

[19]  Marsha B. Liss.  Social and cognitive skills : sex roles and children's play , 1983 .

[20]  Shaun P. Collin,et al.  Philosophical Transactions of the Royal Society of London: Biological Sciences , 2000 .

[21]  J. Rainer.  Sex Differences in Behavior , 1975 .

[22]  J. M. Connor,et al.  Behaviorally Based Masculine- and Feminine-Activity-Preference Scales for Preschoolers: Correlates with Other Classroom Behaviors and Cognitive Tests. , 1977 .

[23]  Irwin Silverman,et al.  Sex differences in spatial abilities: Evolutionary theory and data. , 1992 .

[24]  J. Coutts.  Masculinity-femininity of self-concept: Its effect on the achievement behavior of women , 1987 .

[25]  I. Silverman,et al.  The Hunter-Gatherer theory of spatial sex differences: Proximate factors mediating the female advantage in recall of object arrays , 1994 .

[26]  B. Fagot,et al.  Categorical habituation to male and female faces: Gender schematic processing in infancy** , 1993 .

[27]  M. Meaney.  The sexual differentiation of social play , 1988, Trends in Neurosciences.

[28]  Anne Fausto-Sterling,et al.  Myths of Gender: Biological Theories about Women and Men , 1987 .

[29]  R. Mansfield,et al.  Analysis of visual behavior , 1982 .

[30]  J. Money,et al.  Progestin‐induced hermaphroditism: IQ and psychosexual identity in a study of ten girls∗∗ , 1967 .

[31]  B. McEwen,et al.  Testosterone implants into the amygdala during the neonatal period masculinize the social play of juvenile female rats , 1986, Brain Research.

[32]  Franck Pichaud,et al.  Evolution of color vision , 1999, Current Opinion in Neurobiology.

[33]  C. Crook,et al.  Infants' visual preference for sex-congruent babies, children, toys and activities: A longitudinal study. , 2000 .

[34]  J. Langlois,et al.  Mothers, fathers, and peers as socialization agents of sex-typed play behaviors in young children. , 1980 .

[35]  Cynthia L. Miller.  Qualitative differences among gender-stereotyped toys: Implications for cognitive and social development in girls and boys , 1987 .

[36]  John Tooby,et al.  Evolutionary psychology and the brain , 2001, Current Opinion in Neurobiology.

[37]  S. Baron-Cohen,et al.  Sex differences in human neonatal social perception , 2000 .

[38]  C. Martin,et al.  The development of gender stereotype components. , 1990, Child development.

[39]  Marsha B. Liss.  Patterns of toy play: An analysis of sex differences , 1981 .

[40]  E. Maccoby,et al.  Gender and relationships. A developmental account. , 1990, The American psychologist.

[41]  G. Levy.  Gender-Typed and Non-Gender-Typed Category Awareness in Toddlers , 1999 .

[42]  David J. Freedman,et al.  Categorical representation of visual stimuli in the primate prefrontal cortex. , 2001, Science.

[43]  R. Dittmann,et al.  Congenital adrenal hyperplasia II: Gender-related behavior and attitudes in female salt-wasting and simple-virilizing patients , 1990, Psychoneuroendocrinology.

[44]  J. Nathans.  The Evolution and Physiology of Human Color Vision Insights from Molecular Genetic Studies of Visual Pigments , 1999, Neuron.

[45]  C. Martin.  A developmental perspective on gender effects and gender concepts. , 1999 .

[46]  R. Hirsch,et al.  Preferences of female rhesus monkeys (Macaca mulatta) for infantile coloration. , 1987, Developmental psychobiology.

[47]  B. McEwen.  Sexual differentiation of the brain , 1981, Nature.

[48]  William B. Swann,et al.  Sexism and stereotypes in modern society : the gender science of Janet Taylor Spence , 1999 .

[49]  M. Hines,et al.  Human behavioral sex differences: a role for gonadal hormones during early development? , 1995, Psychological bulletin.

[50]  N. Eisenberg,et al.  Children's Reasoning regarding Sex-typed Toy Choices , 1982 .

[51]  F. Bercovitch,et al.  Behavioral masculinization is independent of genital masculinization in prenatally androgenized female rhesus macaques , 1988, Hormones and Behavior.

[52]  J. Benenson,et al.  Propulsion : A behavioural expression of masculinity , 1997 .

[53]  J. E. Blakemore.  Age and Sex Differences in Interaction with a Human Infant. , 1981 .

[54]  W. Eaton,et al.  Sex differences in human motor activity level. , 1986, Psychological bulletin.

[55]  P. Quinn,et al.  Object recognition and object segregation in infancy: historical perspective, theoretical significance, "kinds" of knowledge, and relation to object categorization. , 2001, Journal of experimental child psychology.

[56]  A. Arnold,et al.  Gonadal steroid induction of structural sex differences in the central nervous system. , 1984, Annual review of neuroscience.

[57]  M. O'brien,et al.  Development of sex-typed play behavior in toddlers. , 1985 .

[58]  E. Maccoby,et al.  The Psychology of Sex Differences , 1974 .

[59]  D. Campbell,et al.  Sex differences in the activity level of infants. , 1999 .

[60]  Diane Poulin-Dubois,et al.  Gender stereotyping in infancy: Visual preferences for and knowledge of gender-stereotyped toys in the second year , 2001 .

[61]  T. Horvath,et al.  Sexual dimorphism and aromatase in the rat retina. , 2001, Brain research. Developmental brain research.