Sex Differences In Play Research Articles

Male chicks play more than females – sex differences in chicken play ontogeny

Play indicates positive affective states and can therefore potentially be used as an indicator of positive welfare. Sex differences in play has been reported in many mammalian species, but in birds, this is still to be explored. It is known that young chickens perform play behavior during their early ontogeny, but potential sex differences have not previously been addressed. Therefore, we aimed to investigate potential sex effects on play ontogeny in young chickens, by comparing play occurrence in young males and females of a commercial hybrid of White Leghorn. Eighteen chicks of each sex were hatched in the same incubator and then housed in sex-separated groups. Six groups of three chicks each were randomly created for each sex, and the same three chicks were then moved to enriched play arenas twice per week, from day 6 until day 53 post hatch. The frequency of different play behaviors, categorized as locomotor play, social play and object play were recorded during 30 min on each observation day. Each group of three birds constituted the independent statistical replicate. Males played significantly more than females, due to more social and object play, whereas for locomotor play, no difference was found between the sexes. In conclusion, clear sex differences in play in chickens was demonstrated, and this may be linked to the highly sexually dimorphic behavior of adult cockerels and hens. Further research is needed to elucidate the relationships between type and frequency of play in chicks and later behavior as adults.

Social play experience in juvenile rats is indispensable for appropriate socio-sexual behavior in adulthood in males but not females.

Social play is a dynamic and rewarding behavior abundantly expressed by most mammals during the juvenile period. While its exact function is debated, various rodent studies on the effects of juvenile social isolation suggest that participating in play is essential to appropriate behavior and reproductive success in adulthood. However, the vast majority of these studies were conducted in one sex only, a critical concern given the fact that there are known sex differences in play's expression: across nearly all species that play, males play more frequently and intensely than females, and there are qualitative sex differences in play patterns. Further limiting our understanding of the importance of play is the use of total isolation to prevent interactions with other juveniles. Here, we employed a novel cage design to specifically prevent play in rats while allowing for other forms of social interaction. We find that play deprivation during the juvenile period results in enduring sex-specific effects on later-life behavior, primarily in males. Males prevented from playing as juveniles exhibited decreased sexual behavior, hypersociability, and increased aggressiveness in adulthood, with no effects on these measures in females. Importantly, play deprivation had no effect on anxiety-like behavior, object memory, sex preference, or social recognition in either sex, showing the specificity of the identified impairments, though there were overall sex differences in many of these measures. Additionally, acute play deprivation impaired performance on a test of prosocial behavior in both sexes, indicating a difference in the motivation and/or ability to acquire this empathy-driven task. Together, these findings provide novel insight into the importance and function of juvenile social play and how this differs in males and females.

The development of sex differences in play in wildwhite-faced capuchins (Cebus capucinus).

Many mammalian species display sex differences in the frequency of play behavior, yet the animal literature includes few longitudinal studies of play, which are important for understanding the developmental timing of sex differences and the evolutionary functions of play. We analyzed social play, solitary play, and grooming using an 18-year data set on 38 wild white-faced capuchin monkeys (Cebus capucinus) followed since infancy. Rates of each behavior were measured as the proportion of point samples taken during focal follows in which the individual engaged in each behavior. To determine sex differences in these rates, we ran a series of generalized linear mixed models, considering both linear and quadratic effects of age, and chose the optimal model for each of the three behavioral outcomes based on information criteria. Rates of both social play and solitary play decreased with age, with the exception of social play in males, which increased in the early juvenile period before decreasing. Male and female capuchins had different developmental patterns of social play, with males playing more than females during most of the juvenile period, but they did not display meaningful sex differences in solitary play rates. Additionally, males and females had different patterns of grooming over the lifespan: males participated in grooming at low rates throughout their lives, while adult females participated in grooming at much higher rates, peaking around age 11 years before declining. We suggest that male and female white-faced capuchins may adopt alternative social bonding strategies, including different developmental timing and different behaviors (social play for males vs. grooming for females). Our results were consistent with two functional hypotheses of play, the practice and bonding hypotheses. This study demonstrates that play behavior may be critical for the development of sex-specific social strategies and emphasizes the importance of developmental perspectives on social behaviors.

Developmental origins of sex differences in the neural circuitry of play

ABSTRACTSocial play consists of reciprocal physical interactions between conspecifics with many features conserved across species, including the propensity for males to engage in play more frequently and with higher physical intensity. Animal models, such as the laboratory rat, reveal that the underlying neural circuitry of play is subject to sexual differentiation during a critical period early in life. In this review, we discuss the developmental processes that produce distinct neural nodes which modulate both shared and sex-specific aspects of play with a focus on the medial amygdala, lateral septum, and prefrontal cortex. While the cellular mechanisms determining sex differences in play are beginning to be uncovered, the ultimate advantages of play continue to be debated.

Development of social learning and play in BaYaka hunter-gatherers of Congo

High-fidelity transmission of information through imitation and teaching has been proposed as necessary for cumulative cultural evolution. Yet, it is unclear when and for which knowledge domains children employ different social learning processes. This paper explores the development of social learning processes and play in BaYaka hunter-gatherer children by analysing video recordings and time budgets of children from early infancy to adolescence. From infancy to early childhood, hunter-gatherer children learn mainly by imitating and observing others’ activities. From early childhood, learning occurs mainly in playgroups and through practice. Throughout childhood boys engage in play more often than girls whereas girls start foraging wild plants from early childhood and spend more time in domestic activities and childcare. Sex differences in play reflect the emergence of sexual division of labour and the play-work transition occurring earlier for girls. Consistent with theoretical models, teaching occurs for skills/knowledge that cannot be transmitted with high fidelity through other social learning processes such as the acquisition of abstract information e.g. social norms. Whereas, observational and imitative learning occur for the transmission of visually transparent skills such as tool use, foraging, and cooking. These results suggest that coevolutionary relationships between human sociality, language and teaching have likely been fundamental in the emergence of human cumulative culture.

Sex differences in juvenile play behavior differ among rat strains.

Juvenile male rats frequently play more than female rats, but the presence of sex differences is affected by testing conditions and may also depend on the strain of rat. In this experiment, we tested play and defensive behaviors in male and female Long-Evans, Sprague-Dawley, and Wistar rats. When observed with a cage mate during the juvenile period, Long-Evans rats played more than Wistar animals, but there were no sex differences in any strain. When tested with an unfamiliar sibling (not seen since weaning), both Long-Evans and Wistar rats played more than Sprague-Dawley animals, and Long-Evans females played more than males. We did not observe any sex or strain differences in defensive behaviors. Our data indicate that there are strain differences in play behavior, and sex differences in play depend on both strain and context. Variation among strains may reflect underlying differences in anxiety, novelty seeking, and circadian rhythms.

Activation of Both CB1 and CB2 Endocannabinoid Receptors Is Critical for Masculinization of the Developing Medial Amygdala and Juvenile Social Play Behavior.

Juvenile social play behavior is a shared trait across a wide variety of mammalian species. When play is characterized by the frequency or duration of physical contact, males usually display more play relative to females. The endocannabinoid system contributes to the development of the sex difference in social play behavior in rats. Treating newborn pups with a nonspecific endocannabinoid agonist, WIN55,212-2, masculinizes subsequent juvenile rough-and-tumble play behavior by females. Here we use specific drugs to target signaling through either the CB1 or CB2 endocannabinoid receptor (CB1R or CB2R) to determine which modulates the development of sex differences in play. Our data reveal that signaling through both CB1R and CB2R must be altered neonatally to modify development of neural circuitry regulating sex differences in play. Neonatal co-agonism of CB1R and CB2R masculinized play by females, whereas co-antagonism of these receptors feminized rates of male play. Because of a known role for the medial amygdala in the sexual differentiation of play, we reconstructed Golgi-impregnated neurons in the juvenile medial amygdala and used factor analysis to identify morphological parameters that were sexually differentiated and responsive to dual agonism of CB1R and CB2R during the early postnatal period. Our results suggest that sex differences in the medial amygdala are modulated by the endocannabinoid system during early development. Sex differences in play behavior are loosely correlated with differences in neuronal morphology.

Play complexity and toy engagement in preschoolers with autism spectrum disorder: Do girls and boys differ?

While sex differences in play have been extensively observed in typical development, only a handful of studies have explored this phenomenon in depth with children with autism spectrum disorders. This study explored sex differences in play complexity and toy engagement within caregiver-child interaction samples for preschool-aged children (2-5 years 11 months) with an autism spectrum disorder who were matched to typically developing children on sex and non-verbal development. Overall we found that girls and boys with autism spectrum disorder were largely equivalent in their play complexity. Despite similar play, girls and boys with autism spectrum disorder differed in a number of ways in their toy engagement, replicating traditional gender differences-girls played more with dolls and domestic items (though at lower rates than typically developing girls) and boys played more with the garage and cars (though at lower rates than typically developing boys). Our findings support the importance and utility of examining sex differences in autism spectrum disorder in light of those observed within typical development.

The acquisition of gender labels in infancy: Implications for gender-typed play.

Two aspects of children's early gender development-the spontaneous production of gender labels and gender-typed play-were examined longitudinally in a sample of 82 children. Survival analysis, a statistical technique well suited to questions involving developmental transitions, was used to investigate the timing of the onset of children's gender labeling as based on mothers' biweekly telephone interviews regarding their children's language from 9 through 21 months. Videotapes of children's play both alone and with mother during home visits at 17 and 21 months were independently analyzed for play with gender-stereotyped and gender-neutral toys. Finally, the relation between gender labeling and gender-typed play was examined. Children transitioned to using gender labels at approximately 19 months, on average. Although girls and boys showed similar patterns in the development of gender labeling, girls began labeling significantly earlier than boys. Modest sex differences in play were present at 17 months and increased at 21 months. Gender labeling predicted increases in gender-typed play, suggesting that knowledge of gender categories might influence gender typing before the age of 2.

Preferências de crianças no brinquedo de Miriti: a influência do gênero e composição da díade

Os dados de investigações sobre diferenças sexuais na brincadeira têm indicado que meninos e meninas preferem brincadeiras e brinquedos diferentes, grande parte desses estudos utilizaram brinquedos industrializados ou atividades de brincadeiras que não envolviam brinquedos. Considerando que tais preferências não se apresentam internacionalmente descontextualizadas, este estudo teve por objetivo verificar a preferência de crianças por determinados brinquedos confeccionados em Miriti (palmeira da região alagadiça - Maurita flexuosa L.) e a existência de variações nessa preferência em função de gênero e da composição da díade. Fizeram parte do estudo 116 crianças com idades entre 4 a 10 anos, provenientes de uma escola municipal. Na sala de coleta ficavam dispostos 52 brinquedos de miriti distribuídos em estantes. As crianças foram agrupadas, seguindo suas preferências, em díades (femininas, masculinas e mistas) e eram conduzidas a sala de observação onde as sessões foram filmadas. Para tratamento dos dados utilizou-se o programa Ethology 2.3, o qual possibilitou medir a freqüência e duração dos episódios de brincadeiras, com determinado brinquedo. No tocante a idade, não foi encontrada nenhuma diferença significativa. Com relação a diferença de gênero, os meninos tenderam a apresentar três brinquedos tipificados, enquanto as meninas em somente um. A despeito das diferenças de sexo identificadas, percebe-se que tais diferenças tendem a ser reforçadas quando as díades são compostas do mesmo sexo, reafirmando diferenças encontradas nas análises dos sujeitos individualizados. Todavia, a análise das díades compostas de dois sexos revela padrões mistos, ora brincando mais de determinados brinquedos preferidos por meninos, ora não apresentando diferenças significativas do grupo das meninas, aproximando-os mais do padrão feminino.

Imaginary Companions and Impersonated Characters: Sex Differences in Children's Fantasy Play

We compared the incidence of imaginary companions and impersonated characters in 152 three- and four-year-old children (75 males and 77 females). Children and their parents were interviewed about role play in two sessions. Although there were no sex differences in verbal ability or fantasy predisposition, there was a significant difference in the form of children’s imaginary characters: girls were more likely to create imaginary companions, whereas boys were more likely than girls to actively impersonate their characters. There were no significant sex differences in the competence ratings of imaginary companions or impersonated characters. These results suggest that it is important to examine the form and function of children’s pretense to understand sex differences in fantasy play. Sex differences in the play of young children are apparent by 13 months of age (Goldberg & Lewis, 1969). Around the world there are fairly consistent differences in the proportion of rough-and-tumble activity, aggression, and use of large spaces, all higher in boys, as well as cooperation, dyadic versus group play, and preference for finemotor toys, all higher in girls (e.g., Borman, Laine, & Lowe, 1993; Cunningham, Jones, & Taylor, 1994; DiPietro, 1981; Lever, 1978; Mac

Gender-Typed Play and Amniotic Testosterone.

Sex differences in play are apparent in a number of mammalian species, including humans. Prenatal testosterone may contribute to these differences. The authors report the first attempt to correlate gender-typed play in a normative sample of humans with measurements of amniotic testosterone (aT). Testosterone was measured in the amniotic fluid of 53 children (31 boys and 22 girls). A strong sex difference was observed in aT and, at ages 4.75 to 5.8 years, on a modified version of the Child Game Participation Questionnaire. Hierarchical regression analyses on the entire group and within-sex correlations suggested that variations in aT did not contribute to individual differences in game participation as reported by the mother. A critique of explanations for this finding is presented.

Sex differences in play among western lowland gorilla (Gorilla gorilla gorilla) infants: implications for adult behavior and social structure.

Mammalian play is believed to improve motor skills as well as facilitate the development of social relationships. Given the marked sexual dimorphism in gorilla body size and the role assumed by the male in protecting the group from conspecifics and predators, the motor-training hypothesis of play predicts that male infants should exhibit higher frequencies of social play than female infants, and that males should prefer to play with other males. Given that adult female gorillas are strongly attracted to adult breeding males and form only weak social bonds with unrelated adult females, the social-relationship hypothesis of play predicts that female infants should prefer to play with males. These hypotheses were tested in a 22-month study of 12 gorilla infants, aged between 0-5 years, living in three zoological parks in Chicago and Atlanta. Consistent with the hypotheses, male infants played more than female infants did, and both male and female infants preferred to play with males rather than with females. These findings suggest that sex differences in play in the great apes and other primates can be predicted by the characteristics of adult behavior and social structure above and beyond the patterns of sex-biased dispersal or coalition formation with same-sex kin.

Sex differences in play fighting revisited: traditional and nontraditional mechanisms of sexual differentiation in rats.

In the traditional model for sexual differentiation in mammals, the female phenotype is the default condition. That is, the female-typical pattern will persist unless acted upon by hormones early in development. The frequency of play fighting in rats, as in most other mammals, is sexually differentiated, and conforms to the traditional model. Males engage in more play fighting than females, and this can be reduced to female-typical levels by neonatal castration. Furthermore, females can be induced to play fight at male-typical levels if treated with testosterone neonatally. Fractionation of play fighting into its constituent components, attack and defense, reveals that it is the frequency of attack that is sexually differentiated, not the likelihood of defense. However, in males, defensive behavior changes at puberty so that the play becomes "rougher." For males to switch to this rougher form of play fighting, they have to be androgenized perinatally. Hence, for males, this second aspect of play fighting that is sexually differentiated also follows the traditional model. In marked contrast, development of the female-typical pattern does not. Neonatal treatment of females with testosterone has no effect; at puberty, they still show the female-typical pattern. On the the other hand, ovariectomy, either at birth or at weaning, leads to females exhibiting the male-typical transition to rougher play fighting at puberty. That is, ovarian hormones appear to actively inhibit the expression of a male-typical trait in females. Play fighting, then, is a mixture of traits, with some features conforming to the traditional model and some not. For some phenotypic features, ovarian hormones appear to exert an active role in their development.

Verbally Expressed Modes of Transformation in the Fantasy Play of Black Preschool Children

McLOYD, VONNIE C. Verbally Expressed Modes of Transformation in the Fantasy Play of Black Preschool Children. CHILD DEVELOPMENT, 1980, 51, 1133-1139. Black, low-income children's verbalized fantasy transformations during a 20-min free-play session were examined. 18 samesex dyads, 6 33,-year-old, 6 5-year-old, and 6 mixed-age dyads composed of a 3/1and 5-year-old partner, equally divided by sex, were observed. Approximately one-half of the girls' and onethird of the boys' utterances represented fantasy transformations, the most frequent of which were animation, reification, and situational attribution, respectively. Children made significantly more object than ideational transformations. Significant sex but no dyad age effects were found. Girls made significantly more transformations overall and significantly more substitution, object realism, and role-attribution transformations than boys. Proportional analyses indicated that girls made relatively more object realism and role-attribution transformations than boys. Boys made relatively more attribution of object property transformations than girls. Results suggest need for further examination of cultural and sex differences in play as a transformational and representational activity.

Teachers' reinforcement of sex-preferred behaviors in dutch preschools.

4-yr.-old children were observed in three Dutch preschools. Significant sex differences in play were found in all schools. These differences were similar to those reported in studies of American preschools. In contrast to American preschool teachers who have been reported to reinforce feminine-preferred behaviors for both boys and girls, these Dutch preschool teachers reinforced children for behaviors preferred by their own sex.

Play in pre-school centres--I. Play measures and their relation to age, sex and I.Q.

SUMMARYThe free play of 109 children aged 3–4 was observed in 12 pre‐school centres, and assessed mi a number of scales. Most of the play measures were found to be age‐related; the major sex differences in play were in the choice of play material and fantasy theme. There were correlations between some of the play measures and the children's unstandardised verbal and non‐verbal test scores. The findings are discussed in relation to pre‐school educational practice.