Interesting post by Gretchen Reynolds reviewing the evidence on exercise and intelligence. The title is “Phys Ed: Can Exercise Make Kids Smarter?”, so this is definitely seen as something which is “actionable” in a public policy sense, especially in light of the increases in obesity among young people. Intuitively I think most people are going to agree with this in the United States. In fact, when you’re down with the flu or some other illness you are generally less productive (most of the films I’ve watched over the past three years have been when I’m ill since I can’t focus on difficult material), so there’s probably going to be a natural connection made between greater cognitive function with greater health.
First, Reynolds points to a study which shows that:
1) The most fit children are more intelligent than the least fit as adduced from psychometric tests
2) The most fit children ‘had significantly larger basal ganglia, a key part of the brain that aids in maintaining attention and “executive control,” or the ability to coordinate actions and thoughts crisply.’ The researchers controlled for socioeconomic status and body mass index,
A second study indicated that the fit children had better working memory and greater hippocampal volume. Finally, an earlier study using data from Swedish conscripts showed that even among identical twins the fitter ones were more intelligent. Note that the primary author was the same on the first two studies. Before commenting further how about looking at some tables and/or figures from the papers?
Poking around the GSS for another reason I stumbled onto something weird. Something which I’d seen hints of, or seen referred to before, but never followed up myself. It seems that support for abortion-on-demand and the death penalty peaked concurrently in the span between 1980-2000. This is evident in two GSS variables, ABANY and CAPPUN, which ask if you support a woman’s right to an abortion for any reason and the death penalty for murder. Additionally, I decided to look at attitudes toward homosexuality using HOMOSEX as a reference as a point of contrast. Unlike abortion or the death penalty attitudes toward homosexuality have been changing in the same direction for the past 30 years. Additionally, the magnitude of the change seems to be much greater than in regards to the other two controversial social issues, and especially abortion, which has exhibited notable stability.
I was particularly interested in differences by religion, so I limited the sample to whites and broke it down by Protestant, Catholic, Jew and None. To reduce sample size volatility I clustered by decade, so that “1970s” is inclusive of every year in the 1970s that the GSS asked the question for that variable.
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