There’s a new paper out by Satoshi Kanazawa which is causing a bit of a stir. You might have seen something about it already – I’m a little behind the curve on this one, but on the plus side I have actually read the paper, unlike many other pundits!

What’s got people talking is the correlation between atheism and intelligence, although that isn’t what the paper is actually about. It’s already pretty well established that atheists tend, on average, to be more intelligent. This paper firms that finding up a bit more, but makes a bigger claim than that.

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There were actually two studies, both using US data. The first looked at intelligence scores from a group of adolescents (junior high and high school), and compared it with their religious beliefs 8 years later.

The figure shows that atheists are smarter by a good few points on average. And the link remained even after Kanazawa corrected for age, sex, race, education, earnings, and even religion. It’s not a trivial difference. In fact the effect is pretty strong – stronger than the effect of education, for example.

The second was from the general social survey – a survey of adults. Once again religion (belief in god and religious intensity) was strongly related to intelligence, even after correcting for a host of factors that you might think could explain the link.

So what? Well, Kanazawa believes that the explanation for the link lies in the Savannah hypothesis. This is the idea that general intelligence evolved as a way to deal with evolutionarily novel situations. It lets us transcend our evolved behaviour and do things that contravene our instincts.

In support of this, Kanazawa shows that intelligence is linked to liberal ideals in the same way. In particular, the link seems to be between intelligence and openness to support of people from other ethnic groups (i.e. whites supporting government intervention to help blacks).

What’s more intelligence in those adolescents increases belief among men (but not women) in sexual exclusivity – i.e. that people should not sleep around.

If Kanazawa is right, then intelligence should not be linked to behaviour that is not evolutionarily novel. And, indeed, attitudes to children, marriage, family and friends are not linked to intelligence.

It’s an interesting hypothesis, and an interesting analysis. To me, it seems intuitively reasonable that general intelligence should have evolved as a way of solving problems. But it will take more than this study (and his previous one) to convince me.

Continues at: http://epiphenom.fieldofscience.com/2010/03/is-this-why-atheists-are-on-average.html

Tom Rees blogs at Epiphenom. He’s a member of the Humanists4Science group which is affiliated to the BHA.