May 30, 2005

Latest on the Flynn Effect

A friend sent me five recent studies on the Flynn Effect of rising raw IQ scores.

- Raw IQ scores stopped going up among draftees in Denmark and Norway about a decade ago and have fallen somewhat. It's hard to say whether this means the Flynn Effect is over there, or whether increasing numbers of immigrants have lowered IQs. Somebody should study draftees' test scores in Finland, where there has been far less immigration.

- IQ scores tend to go up along with average height, although that's not always true.

- Much of the Flynn Effect is on the visuospatial aspects of IQ tests.

- More of the growth has been at the low end of the range than at the high end.

- Veteran teachers in Australia don't think students are getting any smarter, but their colleagues in Singapore, where conditions have improved much faster, do.

- Nobody yet seems to have studied the role of decreasing lead in the environment on the Flynn Effect, but that sounds promising.

- The first study of the Flynn Effect in a 3rd World nation showed a rise of 11 IQ points among small children in a village in Kenya from 1984 to 1998. (I've long argued that the very low IQ scores found among Africans can't be all genetic.) In this village, conditions improved in various ways over those 14 years, such as calorie intake went up by 20%, more schooling, more television, etc. Unfortunately, as is common in studies of black IQs these days, the study doesn't tell you what the actual IQ scores were: I'd guess they were something embarrassingly low like 67 going up to something less awful like 78. But, nonetheless, good news.

A reader writes:

I think all this data is neatly explained by the following two suppositions:

1. IQ is positively correlated with head size.

2. Head size is negatively correlated with surviving birth and early infanthood.

Here is my "Just So" story. Throughout human history, there has been a large variation in head size, and large heads often meant problems during birth, leading to either the child or mother dying in childbirth. As advances in medicine lowered infant death rates, more big-headed babies survived to adulthood . This is driving the Flynn effect.

My published articles are archived at -- Steve Sailer

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