Tuesday, September 02, 2003

The Genetics of IQ: Variance among the non-wealthy?

Genes' Sway Over IQ May Vary With Class (washingtonpost.com): ".. a groundbreaking study of the interaction among genes, environment and IQ finds that the influence of genes on intelligence is dependent on class. Genes do explain the vast majority of IQ differences among children in wealthier families, the new work shows. But environmental factors -- not genetic deficits -- explain IQ differences among poor minorities."
One might guess that genes determine potential IQ, and that environment impacts how well one reaches that potential. Wealthy children function near their potential, but poor children may fall below potential.

A few caveats:

1. Most research suggests that the most important environment is intrauterine. So the journalist is mistaken to think this necessarily strengthens the case for Head Start and other programs. It may strengthen the case for smoking prevention and smoking cessation, for alcohol and substance abstention, for dental care, prenatal vitamins, dietary counseling, etc.

2. The study methodology sounds pretty tortured. This study really only suggest the need for directed research.

3. Rich people are smarter than the rest of us (on average). So they might be seeing an effect that says that high range IQ is highly gene determined, but mid-range IQ is less gene determined.

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