Originally Posted by Beckee
Socioeconomic Status Modifies Heritability of IQ in Young Children
Eric Turkheimer,
Andreana Haley,
Mary Waldron,
Brian D'Onofrio and
Irving I. Gottesman
+ Author Affiliations
University of Virginia

Eric Turkheimer, University of Virginia, P.O. Box 400400, Charlottesville, VA 22904�4400; Email: ent3c@virginia.edu

Abstract
Scores on the Wechsler Intelligence Scale for Children were analyzed in a sample of 7-year-old twins from the National Collaborative Perinatal Project. A substantial proportion of the twins were raised in families living near or below the poverty level. Biometric analyses were conducted using models allowing for components attributable to the additive effects of genotype, shared environment, and non-shared environment to interact with socioeconomic status (SES) measured as a continuous variable. Results demonstrate that the proportions of IQ variance attributable to genes and environment vary nonlinearly with SES. The models suggest that in impoverished families, 60% of the variance in IQ is accounted for by the shared environment, and the contribution of genes is close to zero; in affluent families, the result is almost exactly the reverse.

Arthur Jensen and J.P. Rushton say Turkheimer's study is an outlier:

http://www.alternativeright.com/mai...appy-science/?print=1&tmpl=component
The Happy Science
Forget the Bell Curve, Everyone's a Genius!
By Richard Hoste

...

Shenk cites a 2003 study by University of Virginia psychologist Eric Turkheimer purportedly showing that intelligence is less heritable in lower socio-economic status (SES) groups. This article was a favorite of Nisbett, too, though Jensen and Rushton pointed out at the time that

'The Turkheimer et al. [70] study that Nisbett cites is an outlier. In Britain, the exact opposite of Turkheimer's result was found in over 2,000 pairs of 4-year-old twins (N = 4,446 children), with greater heritability observed in high-risk environments [74]. A re-analysis of the Hawaii Family Study of Cognition also found contrary results to Turkeimer's. Nagoshi and Johnson [75] found no reduction in the relationship between parental cognitive ability and offspring performance in families of lower as opposed to upper levels of socioeconomic status. In the 1,349 families they studied, the relationship remained the same across tests, ethnicity, and sex of offspring.'

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The article above is citing the paper

http://psychology.uwo.ca/faculty/rushtonpdfs/Intelligence%20and%20How%20to%20Get%20It%20(Working%20Paper).pdf

Race and IQ: A Theory-Based Review of the Research in Richard Nisbett�s
Intelligence and How to Get It
by J. Philippe Rushton and Arthur R. Jensen

"To see what is in front of one's nose needs a constant struggle." - George Orwell