Women are scarce in some, but not all, academic disciplines. New work suggests the cause may be a special kind of prejudice—one that also applies to black people

IT IS a long time since the groves of academe were paced only by men, but even now some of them are more populated by women than others are. Why, is a mystery. Though the phenomenon is most discussed in scientific and technological disciplines (new PhDs in maths and physics are earned mostly by men, while—in America at least—half of those in molecular biology and neuroscience are awarded to women), it is equally true in the social sciences and humanities, where art history and psychology are dominated by women, and economics and philosophy by men.

Various explanations have been advanced, beyond differential prejudice in different fields. That the long hours required for laboratory work are unconducive to child-rearing is one. A second is that those subjects in which women are rarest require habits of systematic thought found (it is claimed by some) more often in men. A third is that, though men and women have the same relevant abilities on average, the statistical distribution of these may be wider in men than women. Since academics are people who have these abilities most abundantly, the tail of male geniuses in the bell curve would, if this were true (the evidence is equivocal) be longer than that of female ones.

Suggesting this latter possibility in 2005 helped cost Larry Summers, then president of Harvard, his job, for the subject is political dynamite. A paper just published in Science, though, suggests all these explanations are wrong. What is happening, its authors say, really is just a species of prejudice. Moreover, it is a prejudice which, they think, also explains why some ethnic minorities, black people in particular, are under-represented in a similar way.

The paper’s authors, led by Sarah-Jane Leslie of Princeton university and Andrei Cimpian of the University of Illinois at Urbana-Champaign, hypothesise that the crucial variable is something they call field-specific ability (basically, innate talent)—or, rather, a belief in this quality by those already entrenched in a discipline. They have found that the more existing professors think some special talent, beyond intelligence and hard work, is required to do their subject well, the lower will be the percentage of PhD students in that subject who are women.

Dr Leslie and Dr Cimpian established this by sending questionnaires to more than 1,800 academics working in 30 fields, from astronomy to sociology, at American universities. They asked questions intended to test all four hypotheses, converted the responses into numbers, and then plotted those numbers against the fraction of female PhD students enrolled in the disciplines concerned, looking for correlations.

In the cases of long hours, they asked what a normal working week was. In the case of systematic thought, they asked how important participants believed it was in their own particular disciplines. In the case of the “long tail” they asked how selective the discipline was (that is, what fraction of graduate applicants were admitted), on the presumption that more selective fields would show a stronger long-tail effect, if one exists at all. Finally, on the question of innate talent, they asked questions such as, “Being a top scholar of [discipline] requires a special aptitude that just can’t be taught”, designed to elucidate how important respondents thought it was in their own, particular fields. Only in the case of academics’ assessments of the need for innate talent was there a correlation—and, as the first two charts show, it was strong.

The results on race, illustrated in the third and fourth charts, are also intriguing. Black PhD students show the same types of correlation as women. Americans of Asian descent do not.

Systems of belief

All this raises interesting and awkward questions. It may be unpalatable to some, but the idea that males and females have evolved cognitive differences over the course of many millions of years, because of the different interests of the sexes, is plausible. That people of different races have evolved such differences is far less likely, given the youth of Homo sapiens as a species. Prejudice thus seems a more plausible explanation for what Dr Leslie and Dr Cimpian have observed. But prejudice can work in subtle ways.

It could indeed be that recruiters from disciplines which think innate talent important are prejudiced about who they select for their PhD programmes. It could instead, though, be that women and black people themselves, through exposure to a culture that constantly tells them (which research suggests it does) that they do not have an aptitude for things like maths and physics, have come to believe this is true.

If that is the case (and Dr Leslie and Dr Cimpian suspect it is), it suggests that a cultural shift in schools and universities, playing down talent and emphasising hard work, might serve to broaden the intake of currently male-dominated and black-deficient fields, to the benefit of all.