Sex Differences, Evolutionary Psychology and Biosocial Theory Biosocial Theory is No Alternative

ABSTRACT. Biosocial theory claims that evolution did not design human psy-chological sex differences. It argues that these are the result of the allocation of men and women into different sex roles, based on physical differences. This article argues, however, that biosocial theory is not an alternative to evolutionary psychology in the explanation of human psychological sex dif-ferences. Specifically, biosocial theory is incompatible with evolutionary reasoning and it ignores findings of hormonal psychology, developmental psychology and comparative psychology. Moreover, by posing the need for special explanations, it violates the principle of Occam’s razor. Finally, it does not provide an explanation as to why sex differences in human partner choice are finely tuned to fitness. KEY WORDS: biosocial theory, evolutionary psychology, partner choice, sex differences, sexual behavior Recently, evolutionary psychologists have rekindled an interest in the origin of sex differences. They maintain that the different roles regarding reproduc-tion that men and women have occupied in the course of evolution readily explain most human sex differences. They propose that these different roles have led to different selection pressures on men and women, and that this has resulted in different specialized cognitive mechanisms. This approach has met with some resistance. One of the most influential alternative theories to evo-lutionary psychology in explaining human psychological sex differences is ‘social structure theory ’ (Eagly & Wood, 1999), later refined into the ‘bioso-cial ’ theory of sex differences (Wood & Eagly, 2002). Eagly and Wood have presented this theory in two journals with a high impact in the field: America