THERE WAS SOMETHING SELF-DESTRUCTIVE ABOUT Harvard University President Larry Summers' speech on gender disparities in January. In his first sentence, he said his goal was "provocation" (rarely a wise strategy at a diversity conference). He called for "rigorous and careful" thinking to explain the gender gap among top-tier tenured science professors. But he described his pet theory with something less than prudence. The most likely explanations, he said, are that 1) women are just not so interested as men in making the sacrifices required by high-powered jobs, 2) men may have more "intrinsic aptitude" for high-level science and 3) women may be victims of old-fashioned discrimination. "In my own view, their importance probably ranks in exactly the order that I just described," he announced.
Cue the hysteria. The comments about aptitude in particular lingered, like food poisoning, long after the conference ended. For weeks, pundits and professors spouted outrage and praise, all of which added up to very little. Then came the tedious analysis of faculty-lounge politics at Harvard, as if anyone outside Cambridge really cared.
The rest of us were left with a nagging question: What is the latest science on the differences between men's and women's aptitudes, anyway? Is it true, even a little bit, that men are better equipped for scientific genius? Or is it ridiculous--even pernicious--to ask such a question in the year 2005?
It's always perilous to use science to resolve festering public debates. Everyone sees something different--like 100 people finding shapes in clouds. By the time they make up their minds, the clouds have drifted beyond the horizon. But scientists who have spent their lives studying sex differences in the brain (some of whom defend Summers and some of whom dismiss him as an ignoramus) generally concede that he was not entirely wrong. Thanks to new brain-imaging technology, we know there are indeed real differences between the male and the female brain, more differences than we would have imagined a decade ago. "The brain is a sex organ," says Sandra Witelson, a neuroscientist who became famous in the 1990s for her study of Albert Einstein's brain. "In the last dozen years, there has been an exponential increase in the number of studies that have found differences in the brain. It's very exciting."
But that's just the beginning of the conversation. It turns out that many of those differences don't seem to change our behavior. Others do--in ways we might not expect. Some of the most dramatic differences are not just in our brains but also in our eyes, noses and ears--which feed information to our brains. Still, almost none of those differences are static. The brain is constantly changing in response to hormones, encouragement, practice, diet and drugs. Brain patterns fluctuate within the same person, in fact, depending on age and time of day. So while Summers was also right that more men than women make up the extreme high--and low--scorers in science and math tests, it's absurd to conclude that the difference is primarily because of biology--or environment. The two interact from the time of conception, which only makes life more interesting.