Parental Socioeconomic Status Moderates Genetic Influences on Cognitive Ability in a Diverse Sample of Young Adults

Cognitive ability is an important predictor of multiple life outcomes including educational attainment and better health. And while cognitive ability is heritable, there are significant environmental influences that moderate... [ view full abstract ]

Cognitive ability is an important predictor of multiple life outcomes including educational attainment and better health. And while cognitive ability is heritable, there are significant environmental influences that moderate genetic ability (Tucker-Drob and Bates; 2016; Psych Science 2, 138–149). We examined whether genome-wide polygenic scores for educational attainment (EDU PGS) predict cognitive ability (SAT scores), and whether this influence is moderated by parental socioeconomic status (SES). Data for these analyses come from a longitudinal study of college students enrolled in a large, public university (N=5,953) who provided DNA. SAT scores were ascertained through student registry data. EDU PGS were created using summary statistics from a recent large scale GWAS of educational attainment (Okbay et al., 2016; Nature; 533, 539–542). Parental SES was derived from survey reports of parental education. We fit a series of linear models across ancestral population and meta-analyzed the results with sex and ancestry principal components as covariates. EDU PGS explained 1.5%-3.5% of the variance in SAT scores across ancestral groups. Main effects for EDU PGS and parental SES were significant in the meta-analysis. We found significant interactions between parental SES and EDU PGS for those of European and South Asian ancestry, such that the association between EDU PGS and SAT scores was stronger for those from high SES families. For those of African ancestry, parental SES moderated EDU PGS such that the association was stronger under conditions of lower SES. Genome-wide polygenic scores significantly predicted cognitive ability in a diverse sample of college students. Additionally, for some groups, genetic associations were stronger as parental SES increased, similar to previous findings among twins in US samples. These results underscore the importance of examining genetic and environmental interplay in complex outcomes and the heterogeneity of environmental influences of those from diverse backgrounds.