a nice just-so story?

Blogging on Peer-Reviewed Research The Herald this morning had a breathless front-page story on how evolution explains why men are better than women at map-reading. My immediate reaction was, r-i-i-i-ght. It sounded awfully like a just-so-story from evolutionary psychology, to me.

According to the article,

The cliches that women can’t read maps and men can’t see things right under their noses seem to have been explained by science. Researchers believe the reason the sexes differ is because of their specific roles in evolution. Men had to hunt and stalk their prey, so became skilled at navigation, while women foraged for food and became good at spotting fruit and nuts close by.

And where did this come from? The journalist wrote: The theory emerged from a study which looked at the different way in which men and women appreciate art.

Excuse me a minute while I vent…. This is not a theory!!! It’s an hypothesis – based on a single study of the neurological responses of 10 men & 10 women to a series of paintings and photos of landscapes & other scenery! Where’s the data relating that to navigation? There. That feels better.

Anyway, the report is based on a paper recently published in the Proceedings of the National Academy of Scientists (Cela-Conde et al. 2009). A research team used a technique called magnetoencephalography to measure the brain activity of their study groups while the members of those groups decided whether or not the images they were viewing were beautiful. They found that when one of their volunteers felt an image to be beautiful, a particular part of the brain (the parietal) became more active. So they were looking at brain activity in relation to a subjective response. There appeared to be gender differences in this activity – in women, the activity occurred on both sides of the brain, while in men it was mainly the right parietal region that was involved.

The team concluded that men & women have different neural mechanisms for appreciating beauty, & that these have been shaped by evolution, perhaps working through sexual selection. They argue that these differences are related to different spatial abilities in the two sexes – presumably located in the parietal region, & that these in turn were associated with the division of labor between the sexes in hunting and gathering – tracking animals & foraging for plants supposedly require different spatial skills. And this purportedly makes men better at navigating than women. (I did wonder why, given that the ‘navigation’ side of the brain was as active in women looking at pretty pictures, as it was in men…)

This seems to me to be a rather big leap, given that there was no attempt to record the brain activity of the experimental subjects while they were attempting a navigation task, so we can’t know if the proposed link is likely to be an actual one. And how could neurological differences in an aesthetic response to an image (or a person) link to the ability to navigate, anyway? What is the proposed mechanism?

And, if you look at the Kung people of the Kalahari, while men hunt game over long distances, women also forage extensively away from the camp – they must still be able to navigate, & both sexes would make some use of landmarks to do so. And women also catch & kill animals (birds, reptiles, & small mammals) – while this sort of hunting is opportunistic, it will still require some ability to stalk prey, & to keep in mind an awareness of where that prey is relative to the hunter. In both sexes.

I can’t help a feeling that the way the press presented this story is on a par with the idea that reactions to loud car noises are is a primeval response. Or the one that women really do prefer pink, & that this has been shaped by evolution so that we can better see the nice red berries that we forage for. As Ben Goldacre says, there’s actuall very little evidence of any genetic influence on behaviour, emotion, and cognition. Perhaps the idea that women can’t read maps really is just a cliche, after all…

C.J.Cela-Conde, F.J.Ayala, E.Munar, F.Maestu, M<.Danal, M.A.Capo, D.del Rio, J.J.Lopez-Ibor, T.Ortiz, C.Mirasso, & G.Marty (290) Sex-related similarities and differences in the neural correlates of beauty. PNAS doi/10/1073/pnas.0900304106

One thought on “a nice just-so story?”

  • I’m one of those unfortunate males who can’t navigate, but it seems to me that if this study is applicable to navigation at all (a stretch) then it surely shows that women would devote more brain power to the task. I have read that women tend to navigate using landmarks more than men, perhaps this is related. I am however with you in not really seeing how this study could possibly shed any light on this.
    There are already papers published showing deficiencies in the conclusions we reach when we look at the brain activity of people while trying to elicit the trait we are hoping to explain* let alone one that doesn’t seem to be related at all.
    * http://www.edvul.com/pdf/Vul_etal_2008inpress.pdf

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