Biological Sex Differences and Competition

Abstract There is evidence of the existence of biological differences between males and females at multiple levels. Sex differences are shown in both genotypic and phenotypic dimensions in almost all species. Body differences are apparent, but differences in many other systems, including the neuro-endocrine-immune system, are also very important and related to evolutionary aims. Brain differences have been reported in recent decades in numerous structures, neurotransmitters, pathways, etc. These differences are reflected in behavioral and other cognitive and affective processes that have attracted considerable attention from researchers and the general public. Some of the clearest behavioral differences are aggressive and violent behavior, spatial orientation, mathematics and language skills, and other differences related to reactivity to stress. Agonistic or competitive behavior has been studied for decades, particularly in males in many different species, including humans, although more recently interest in female intrasexual competition has increased. Several differences in the competitive behavior of men and women, as well as in the underlying mechanisms, have begun to be established, mainly related, at least partially, to biological and social dimensions. In this chapter, the authors will review results found in the research on the biological basis of sex differences and its impact on competition.