Age and sex differences in aggression among the Aka foragers of the Central African Republic

Aggression is often considered a maladaptive behavior, and is an important social problem cross-culturally. There are two primary theoretical arenas examining the origins of age and sex differences in aggression. Evolutionary theories assert that sexual selection has shaped the age and sex differences in physical (e.g., hitting) and indirect (e.g., gossiping) aggression, suggesting that males make use of physical aggression in resource competition and social dominance while females rely on less risky strategies of indirect aggression for the same purposes. Biosocial theory ties sex differences in aggression to the inculcation of sex roles, with social norms serving to reinforce these divergences via expected behaviors with punitive consequences for violations. The majority of previous work on aggression in small-scale societies has emphasized its absence, particularly among hunter-gatherers. This paper examines age and sex differences in physical and indirect aggression, and in cultural norms surrounding aggression, among the Aka forest foragers of the Central African Republic. Both peerrankings and self-report data were collected from 98 Aka (children, adolescents, and adults) on physical and indirect aggression; additional data on anger, reputation, and alliances were obtained from adults. A Likert scale was used to obtain measures of social norms, perpetration, and victimization. The results provide only mixed support for evolutionary theories on aggression. Although the expected sex-bias in hitting emerged among children and adolescents, this effect disappeared among adults. An adult female bias in gossiping emerged only when anger was added to the model, and no bias was found in children or adolescents. Our negative findings might be due to unmeasured social and cultural factors, such as high levels of relatedness, the role of women as disciplinarians, and reduced male testosterone due to high levels of paternal investment. As there is little research on hunter-gatherer aggression, it is currently unclear where the Aka fit on aggression measures among small-scale societies. However, these results indicate the importance of quantifying aggressive behaviors in order to clarify the effects of biology, environment, and culture in the development and evolution of aggression, and perhaps reveal current biases derived from the emphasis on Western populations in the literature