A Cross-Species and Cross-Cultural Comparative Analysis of Sex and Gender Differences in Rough and Tumble Play

Abstract

Rough and tumble play (RTP) is a form of physically active social play common across diverse social mammals, including humans, which likely provides vital opportunities for the development of physical and social skills. Where adult behaviours are differentiated by sex or gender, RTP is expected to take correspondingly different forms in juveniles. However, we do not yet have a good understanding of how and why sex/gender differences in RTP vary across non-human species and human societies. The first aim of this thesis was to investigate cross-species variation in sex differences in rough and tumble play (RTP) in non-human mammals through the lens of behavioural ecology and life history theory. A systematic review revealed that male biases in RTP are not as consistent as predicted and many studies report a lack of, or inconsistent, sex differences. Contrary to expectations, phylogenetic comparative analyses found no evidence that measures of male-male competition in adults predict male biases in juvenile RTP across species. The second aim of the thesis was to investigate variation in gender differences in RTP in human subsistence societies using cross-cultural data through the lens of cultural evolution. I found that RTP is more common in boys, although in most societies both girls and boys engage in some form of RTP. Gender differences in RTP are not predicted by marriage system or other potentially relevant variables, and are not strongly affected by shared cultural history or spatial proximity. Taken together these results suggest that RTP is a complex, highly variable behaviour which may change rapidly in response to social and environmental factors. I consider potential interactions between biological, cultural, and contextual factors which may explain these findings, call for future work which considers biocultural approaches to sex and gender differences in RTP, and suggest methodologies for improving future research.