There appears to be an insatiable public appetite for information about gender differences in the human brain, eagerly harnessed by the media in many forms. A paper from this week from a research group at Stanford University has made headlines for its innovative contribution to this form: using an AI neural network model to look at brain scans to see if they “reliably” and “robustly” differentiate female and male brains from each other can distinguish In other – more neutral – words, could the algorithm tell whether the brain patterns being looked at came from women or men?
The answer was “yes”, although rather more guarded in the newspaper itself than in the reports about it. What was interesting about the study was that it seemed to move beyond the stereotypical “size matters” agenda – asking whether male or female brains are larger or smaller in different areas – instead measuring differences in the working brain by a method that looked at differences. in blood flow to various brain regions.
But frustratingly, when they did find differences, the explanations were only in terms of sex (in the traditional binary, biological sense of the word). We really need to stop talking about “male” and “female” brains—and rigidly use that particular lens to evaluate and report on data that is interesting in so many other ways. Arguments about gender differences in the brain have raged for centuries. Early fighters were quite vocal about what they were trying to prove, particularly the inferiority of the female brain. It would be so good to move on from this.
This paper obviously does not want to draw any conclusions about the value, or even the significance, of the differences they found, but the impression we are left with – magnified by the media interest it has generated – clearly reflects an ongoing “hunt for sex”. differences” agenda. There seems to be an inexorable need, even in today’s world, to find a nice set of biologically programmed, sex-specific differences in the brain, and agree that these must be the basis of any female-male differences in behavior , or temperament, or ability and performance.
As for the science itself, there were two key truths that this article and its coverage overlooked. The first concerns the difference between sex and gender – which in the old days might have been considered the nature vs nurture argument. We now know our brains are malleable and changeable throughout our lives. When you can tell by looking at the scan of an expert musician whether they are a keyboard player (see the symmetrical representation of finger control centers in the brain) or if they are playing a stringed instrument (showing asymmetrical control centers), it gives a nice good indication that our brains reflect the lives they have lived or the skills they have acquired. This means that when most studies look at adult scans, they see a brain that has been shaped by lifelong experiences, not just by any potential “hard-coded” differences.
The second thing to note about brains is that they evolved to make us social creatures. What no one, including the paper’s authors, seems to have picked up on is that the areas of the brain found to most reliably differentiate women and men are key parts of the social brain network, which has evolved to be uniquely tuned to social interactions, and paying attention to the outside world and to other people. The default mode network is the part of the brain in which we store key elements of social knowledge acquired through interaction, from the moment of birth (if not before) with the outside world – about oneself and about other people, about social rules and social norms, and even social stereotypes.
The 1,500 young adults in this study were between 20 and 35 years old – just think what a treasure trove of experiences will be reflected in their brains. This is not to say that what determines how our brains work is “all culture and no biology”. It is entirely plausible that there may be sex-related differences in how brains are shaped by social experiences. But it does mean that, when we study diverse groups of people, just knowing that the brains come from young female adults, as opposed to young male adults, will never give us the full picture of where any differences come from.
Researchers must recognize that, despite the thousands of research articles with the term “sex differences” in their title, there is little or no consistent and conclusive evidence that any brain differences found can be attributed solely to biological sex.
Essentialist assumptions like this have negative consequences. Only last month David C Geary, a well-known evolutionary psychologist, said that we should question the wisdom of policy interventions to reduce gender gaps if there is any evidence that they arise from “substantive biological contributions”. Commentary on the so-called gender equality paradox cites unspecified “endogenous factors” as an explanation for the fact that the most gender-equal countries have the greatest underrepresentation of women in science, without noting that these very countries also have the most entrenched. gender stereotypes about women’s scientific abilities.
If we continue to buy into the argument that differences between men and women are hard-wired, permanent and intractable, then any attempts to address inequalities will be too easily dismissed, with “what the science says” to blame gain.
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Prof Gina Rippon is Emeritus Professor of Cognitive Neuroimaging at the Aston Brain Centre, Aston University, and the author of The Sexual Brain
