Comparative perspectives on human gender development and evolution

Abstract

Human behavioral sex differences are ubiquitous, but the degree to which these sex differences are evolved or culturally invented is hotly contested across disciplines. A review of the human research yields strong evidence that somatic and social causes are both important in human behavioral sex differentiation, but researchers in this area struggle to agree on the relative importance of each. Understanding the social and somatic determinants of nonhuman primate sex-typed development may shed light on the relative responsibility of social and somatic causes of human behavioral sex differentiation. A review of this research (and related research on the proximate drivers of nonhuman primate behavioral development more generally) indicates that primate behavioral sex differentiation is rooted in somatic causes, but that these are situated in and cannot be extricated from social influences. Overt gender socialization and phenomena such as gender performance seem to be uniquely human. Primate research using a dynamic systems theoretical approach to behavioral development has the greatest potential to further clarify the workings of human behavioral sex differentiation, and further primate research is indispensable for understanding the evolution of human sex-typed behavior.