Podium: A revolution of the sexes

From a lecture at the LSE by the Professor of Law at Wayne State University, Detroit

IMAGINE A world in which women had a virtual monopoly on political power; where women out-competed men in the quest for positions of high status; where women, upon giving birth, left their babies with their husbands who stayed home and kept house; and where the Army, Air Force and Marines were made up mostly of women.

For those raised on the assumptions of standard social science, this Utopia could conceivably come to pass. For them, the primary obstacles to achieving it are arbitrary cultural beliefs about the two sexes.

For those who believe that human psychology is a product of eons of evolutionary history, however, this hypothetical world is simply incompatible with our innate psychology, no more likely to occur than a population of pigs deciding to sprout wings and fly.

Natural selection, specifically sexual selection, has shaped the human mind to create a "human nature". In fact, in some ways it is not too much of an exaggeration to say that it has created two "human natures", a male nature and a female nature.

The reason that the sexes differ in temperament is that different traits have been advantageous to the reproductive success of members of the two sexes. A characteristic feature of mammalian reproduction is that the female must invest substantial physiological resources in offspring, during both pregnancy and nursing. The minimum necessary investment of the male involves participation in a single sexual encounter (a burden, as we know, that men are all too willing to shoulder). Thus, a male can enhance his reproductive success by acquiring multiple mates in a way that a female cannot.

The question, then, is what distinguishes the successful from the unsuccessful male?

The long period of dependency of human young creates substantial pressure for male post-conception investment, so the woman, from time immemorial, has looked to her mate for provisioning and protection. Who can provide those things? Obviously, it must be someone with both the ability and the inclination to do so. Therefore, for a woman, important attributes of a mate are status and resources (and, of course, a willingness to share those resources).

Because the quest for status entails competition with other men, men are predisposed to engage in the competitive, risky and aggressive behaviours that may be required to attain it.

Women, on the other hand, would generally gain no reproductive advantage through open competition for status or from exposing themselves to substantial risk. Instead, they have enhanced their reproductive success by providing direct care for their offspring, probably accounting for the stronger bond between mother and infant than normally exists between father and infant.

Temperamental sex differences can explain a pattern that is otherwise puzzling. Is the representation of women in high positions today the maximum number that female biology is capable of achieving? The answer is a resounding "No". As corporate suites become increasingly populated by people who entered the labour force in the Eighties and Nineties, rather than in the Sixties and Seventies, the number of women should continue to rise.

On the other hand, it is unlikely that women will ever achieve parity at the highest levels. Fortune profiled the women of the Harvard Business School class of 1983. Many of these women have been immensely successful, with a number of them earning more than $1m per year. On the other hand, about a third of the women either work part time or have left the labour market altogether, most to spend time with their families. The "glass ceiling" metaphor is meant to evoke an image of an impermeable but invisible barrier that holds women back. But women who make the same career choices as men can reach the corporate pinnacles, and many do. A more apt term is "gossamer ceiling", which evokes just the opposite image. It is a barrier that women often "see", but that is not strong enough to hold them back if they choose to cross it.

Women who are potential CEOs and who leave the workforce to be with their children do not do so because they cannot afford child care; they are typically highly paid employees already. Instead, they leave because they feel a strong desire to be with their children, a predictable urge for a mammalian mother.

The question for policy makers is not whether they should base policy on a particular view of human nature; rather, it is a question of which view of human nature they should adopt.