Genetics and Health

The Genetics of Intelligence

by Hsien Hsien Lei, PhD on June 5th, 2005

A contentious debate is brewing right now about the genetics of intelligence. Researchers at the University of Utah hypothesize that the higher prevalence of genetic diseases, such as Tay Sachs, in the Ashkenazi Jewish population correlates with higher intelligence. (The Economist, June 2, 2005)

Ashkenazim generally do well in IQ tests, scoring 12-15 points above the mean value of 100, and have contributed disproportionately to the intellectual and cultural life of the West, as the careers of Freud, Einstein and Mahler, pictured above, affirm. They also suffer more often than most people from a number of nasty genetic diseases, such as Tay-Sachs and breast cancer. These facts, however, have previously been thought unrelated. The former has been put down to social effects, such as a strong tradition of valuing education. The latter was seen as a consequence of genetic isolation. Even now, Ashkenazim tend to marry among themselves. In the past they did so almost exclusively.

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…people with a single copy of the gene for Tay-Sachs, or that for Gaucher’s, or that for Niemann-Pick should be more intelligent than average. Dr. Gregory Cochran and his colleagues predict they will be so by about five IQ points.

Not being an expert on the genetics of psychology and intelligence, I don’t know if these findings are valid. What I do know, however, is that the recipe for success is complex and has many ingredients. Most important to remember is that the meanings of intelligence and success vary between cultures.

How do an extra five or ten IQ points translate in the real world? In modern civilzation where education is highly valued, there’s still no guarantee that a person with an exceptionally high IQ will make it big if she or he is a slacker in school, doesn’t test well, and/or doesn’t get along well with others.

While this debate is interesting, I’d rather talk about other more constructive ways to help everyone succeed regardless of genetic predisposition, like improving the quality of after-school care, lowering the high school dropout rate, and increasing college financial aid.

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POSTED IN: General Genetics and Health