Neuro Nonsense

No one disputes that male and female brains are different or that males and females differ in their accomplishments. But are these two facts related? A few years ago Harvard President Larry Summers suggested that the answer is yes. He proposed that innate brain differences help to account for the dearth of successful women in science, provoking much heated debate. Reporters called it the story that would not die. Unlike most news stories that exhaust themselves after a few days, this story stayed in the news for months, and even years later continues to inspire debate. Apparently many of us think we already know the answer to this question—the subject of Cordelia Fine’s highly readable and enjoyable new book Delusions of Gender: How Our Minds, Society, and Neurosexism Create Difference [1]. At least half of us—not just the men—seem to think the answer is yes whereas the other half say not so. You all know where I stand on this issue. Based on my experiences as a neurobiologist and as a transgendered person, I have previously argued that innate sex differences in the brain are not relevant to real-world accomplishments [2,3]. Without question, male and female brains have different circuits that help to control their different reproductive behaviors. So it has long seemed an easy step to believe that such anatomic changes also underlie supposed gender differences in cognitive abilities. Rather, in a theme that Fine elegantly expands on, it is the idea itself that women are innately less capable that may be the primary cause of differences in accomplishment. This idea Fine appropriately dubs ‘‘neurosexism.’’ This idea was long ago powerfully encapsulated in the concept of ‘‘stereotype threat,’’ the phenomenon in which members of a sex or race perform substantially worse on a test—and perhaps in real-world environments—when they are led to believe before the test that they are innately less capable [4]. Fine is an academic psychologist who previously authored A Mind of Its Own: How Your Brain Distorts and Deceives [5]. She decided to write Delusions of Gender after she discovered that her young son was taught at school that boys were not as good at empathizing as girls. Stunned by this experience, Fine critically scoured the relevant scientific literature. Her analysis of this data should be required reading for every neurobiology student, if not every human being. (I wonder if Norton Press might be so good as to send Larry Summers a free copy?) The main theme of Fine’s new book is that current widespread beliefs about gender—that is, we needn’t worry about social or cultural factors leading to sex inequality because hardwired differences between the sexes are to blame—just don’t bear up to scrutiny. For instance, many studies have found that developmental differences in testosterone level result in permanent differences in brain hard-wiring. Are these differences relevant to cognitive abilities? Simon Baron-Cohen thinks so, reporting that developmental hormonal differences cause men to be more systematic thinkers, better at analyzing and exploring, while making women more empathetic [6].His findings have been used by many, including Steven Pinker [7] and Peter Lawrence [8] to argue that men are innately more likely to succeed in science. But Fine raises devastating questions about Baron-Cohen’s methodology, raising serious concerns about poorly defined and socially biased questions used in his questionnaires in some of these studies. In a highly influential study, for instance, he and a student reported that newborn boys prefer to look at mobiles, whereas newborn girls prefer to look at faces. But the study’s design did not prevent the possibility that the experimenter might inadvertently give different cues to the boys and girls. Her critique raises significant doubt about whether Baron-Cohen’s conclusions about sex differences are correct. Even if his measurements were correct, it is not clear that differences observed in newborns are relevant to adult behavior. Lastly, the differences observed were not particularly large, a problem that, Fine points out, applies to many other reported cognitive differences as well. Such differences are often small enough that social experiences can often easily remove them. For instance, the small gender differences observed in spatial abilities can largely be obliterated by practicing mechanical tasks. Fine raises many points that are often neglected in interpreting the results of studies on cognitive sex differences. For instance, she points out that only studies that find a difference are published whereas negative results, which may be more common, are not reported. She points out the many interpretation abuses of modern neuroimaging studies. For instance, the brain’s well-documented Fine C (2010) Delusions of Gender: How Our Minds, Society and Neurosexism Create Difference. New York: W. W. Norton and Company. 338p. ISBN 97800393068382 (hardcover). US$25.95. doi:10.1371/journal.pbio.1001005.g001