Review

Identifying and explaining apparent universal sex differences in cognition and behavior

With growing recognition that there are universal sex differences in cognition and behavior, four theories have been proposed to account for these differences: the founder effect theory, the social structuralist theory, the evolutionary theory, and the evolutionary neuroandrogenic (ENA) theory. The latter of these theories is described in considerable detail as offering an explanation for most of 65 recently identified apparent universal sex differences (AUSDs) in cognition and behavior. Regarding “ultimate causes” (why), ENA theory asserts that (a) evolutionary-genetic factors incline females to bias their mate choices toward males who are loyal and competent provisioners of resources and (b) males are merely a genetic variant on the female sex selected for responding to female mating biases. In terms of “proximate causes” (how), the theory maintains that high exposure to androgens has evolved to alter the male brain functioning in two specific ways relative to most female brains: (a) suboptimal arousal and (b) a rightward shift in neocortical functioning. These two functional patterns are described and hypothesized to incline males and females to learn differently in many respects. The most fundamental differences involve males learning ways of either complying with or circumventing female mate preferences. Numerous universal sex differences in cognition and behavior are hypothesized to result from these evolved neurohormonal factors, including most of the 65 AUSDs herein summarized in seven categorical tables.