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Genotype by environment interaction in adolescents' cognitive aptitude
K Paige Harden1, Eric Turkheimer, John C Loehlin
1Department of Psychology, University of Virginia, P.O. Box 400400, Charlottesville, VA 22904, USA. kph3k@virginia.edu
Behavior Genetics
|September 16, 2006
Summary
Socioeconomic status impacts how genes influence IQ. Environmental factors in wealthier homes allow genetic potential for intelligence to be better expressed in adolescents.
Area of Science:
- Behavioral Genetics
- Developmental Psychology
- Psychometrics
Background:
- The heritability of IQ is influenced by socioeconomic status (SES). Turkheimer et al. (2003) proposed that shared environmental influences on cognitive abilities are stronger in lower SES families, while genetic influences are stronger in higher SES families.
- Bronfenbrenner and Ceci's (1994) bioecological model suggests that gene-environment interactions shape developmental outcomes.
Purpose of the Study:
- To replicate Turkheimer et al.'s (2003) findings on the interaction between socioeconomic status and the heritability of IQ in adolescents.
- To investigate genotype-environment (G x E) interactions in cognitive aptitude.
Main Methods:
- Replication study using data from 839 twin pairs who completed the National Merit Scholastic Qualifying Test in 1962.
- Analysis of shared environmental and genetic influences on cognitive aptitude in relation to parental income and education.
Main Results:
- Shared environmental influences on cognitive aptitude were more pronounced for adolescents from lower socioeconomic backgrounds.
- Genetic influences on cognitive aptitude were more significant for adolescents from higher socioeconomic backgrounds.
- No significant differences were observed between the interaction effects of parental income and parental education.
Conclusions:
- Environmental factors associated with middle- to upper-class families play a role in the expression of genetic potential for intelligence.
- Findings support the concept of gene-environment interaction, where environmental contexts modulate genetic influences on cognitive abilities.
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