Taking Sax and Brooks to Task

Mark Liberman has two great posts over at Language Log debunking first a claim made by David Brooks in this article on the gender gap in education, and then Leonard Sax's poor use of science that inspired Brooks' claim. This is what Brooks wrote:

There are a couple of reasons why the two lists might diverge so starkly. It could be men are insensitive dolts who don't appreciate subtle human connections and good literature. Or, it could be that the part of the brain where men experience negative emotion, the amygdala, is not well connected to the part of the brain where verbal processing happens, whereas the part of the brain where women experience negative emotion, the cerebral cortex, is well connected.

Brooks got this from Sax's book Why Gender Matters, in which Sax wrote:

Girls and boys behave differently because their brains are wired differently.

Deborah Yurgelen-Todd and her associates at Harvard have used sophisticated MRI imaging to examine how emotion is processed in the brains of children from the ages of seven through seventeen. In young children, these researchers found that negative emotional activity in response to unpleasant or disturbing visual images seems to be localized in phylogenetically primitive areas deep in the brain, specifically in the amygdala. (A phylogenetically primitive area of the brain is one that hasn't changed much in the course of evolution: it looks pretty much the same in humans as it does in mice.) That may be one reason why it doesn't make much sense to ask a seven-year-old to tell you why she is feeling sad or distressed. The part of the brain that does the talking, up in the cerebral cortex, has few direct connections to the part of the brain where the emotion is occurring, down in the amygdala.

In adolescence, a larger fraction of the brain activity associated with negative emotion moves up to the cerebral cortex. That's the same division of the brain associated with our higher cognitive functions -- reflection, reasoning, language, and the like. So, the seventeen-year-old is able to explain why she is feeling sad in great detail and without much difficulty (if she wants to).

But that change occurs only in girls. In boys the locus of brain activity associated with negative emotion remains stuck in the the amygdala. In boys there is no change associated with maturation. Asking a seventeen-year-old boy to talk about why he's feeling glum may be about as productive as asking a six-year-old boy the same question.

Liberman goes to the scientific article that Sax cited in support of this claim, and finds that it shows no such pattern. He also quickly surveys some of the relevant literature, and finds that it largely contradicts the claim made by Brooks and Sax. Liberman ultimately concludes:

Is there any conclusion whose empirical and logical foundations are adequately established by Brooks' column? In my opinion, there's at least one: we shouldn't accept any public policy recommendations on the basis of Brooks' understanding of cognitive neuroscience.

Classic. This sort of thing is exactly what I think the science blogosphere is good for: exposing the misuse and misrepresentation of science by the media and politicians/pundits, and I don't think I've seen a better such exposition than Liberman's. So go check it out.