Sex Differences Are Not Hardwired

Although many examples of sex differences in behavior are exaggerations of minute and even trivial differences, there is no denying the existence of some sex differences in perception and cognition; and, therefore, it is important to ask what causes them. There are two radically different types of explanation of the cause: (1) unitary explanations and (2) interactive explanations. Unitary explanations claim that the differences are determined by the genes. In these explanations, higher-level accounts of sex differences in behavior and social position are reduced to accounts at the molecular level, and differences in behavior are said to be "hardwired," "a blueprint," "innate," or "essential." Genes, it is believed, have ultimate control either by acting directly to determine sex differences in brain structure and neural connections or by determining the levels of sex hormones, which, in turn, determine these differences. By contrast, interactive explanations take experience (including learning and other cultural influences) into account and consider that during every stage of development contributions from experience, genes, and hormones interact in such complex ways that no one of these three sources of influence makes an overriding contribution in determining the sex differences in behavior. Note that the debate about the cause of sex differences has moved away from the simple nature-versus-nurture dichotomy that used to be hotly debated some years ago. Interactive explanations do not deny contributing effects of the genes and hormones but take into account the fact that their expression is influenced by experience and that is impossible to separate out any one of these influences from another (Bateson and Martin 1999, Rogers 2001; Rose 1997). Even those who claim that genes arc the main cause of sex differences will often give lip service to a contribution of experience, although, ultimately, they see this as a minor effect compared to the effect of the genes.