August 28, 2005

My new column on Charles Murray's "The Inequality Taboo:"

My new column on Charles Murray's "The Inequality Taboo:"

One of the most newsworthy aspects of "The Inequality Taboo" is Murray's view that the white-black IQ gap may have narrowed slightly in recent years. According to Murray's article, the three most recent re-normings of major IQ tests came up with a mean white-black gap of 0.92 standard deviations, or 14 points.

That doesn't sound like much of a change from the one standard deviation (15 points) racial gap that IQ realists have been talking about for decades. But, in reality, they've been intentionally understating the traditional size of the difference. A 2001 meta-analysis of eight decades of data suggested a 1.1 standard deviation gap (16.5) points. So, if this new 14 point gap found in the three recent re-normings holds up as more data comes in, we may have seen some significant progress on this massive social problem.

Currently, though, the evidence remains far from clear. Murray writes in a footnote:

"Forced to make a bet, I would guess that the black-white difference in IQ has dropped by somewhere in the range of .10–.20 standard deviations over the last few decades. I must admit, however, that I am influenced by a gut-level conviction that the radical improvement in the political, legal, and economic environment for blacks in the last half of the 20th century must have had an effect on IQ."

Murray is too honest, however, to skip over the other, more disturbing, possibility: that the greater fertility of lower IQ women has had a dysgenic and/or "dyscultural" effect. Murray has calculated that 60% of the babies born to black women who began participating in the National Longitudinal Study of Youth in 1979 were born to women with IQs below the black female average of 85.7. Only 7% were born to black women with IQs over 100.

I hope that the improved nutrition, health care, and other environmental enhancements that have allowed African-Americans to come to dominate basketball, football, and sprinting in recent decades have also driven up black IQ scores more than the tendency of intelligent black women to remain childless has driven them down.

But the overall situation remains murky. It needs more research than is currently being funded.

Does part of the white-black IQ gap have a genetic basis? Murray suggests an experiment that might prove conclusive:

"To the extent that genes play a role, IQ will vary by racial admixture. In the past, studies that have attempted to test this hypothesis have had no accurate way to measure the degree of admixture, and the results have been accordingly muddy. The recent advances in using genetic markers solve that problem. Take a large sample of racially diverse people, give them a good IQ test, and then use genetic markers to create a variable that no longer classifies people as 'white' or 'black,' but along a continuum. Analyze the variation in IQ scores according to that continuum. The results would be close to dispositive."

I bet, however, that Murray's critics won't rush to fund this study and put their money where their mouths are. [More]

My published articles are archived at -- Steve Sailer

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