The Moderating Effects of Socioeconomic Status on the Heritability of Math and Reading Achievement

The observation that general cognitive ability measured in children raised in higher socioeconomic status (SES) homes is more heritable than when measured in children raised in lower SES homes has been found in samples collected in the United States (Tucker-Drob & Bates, 2016). Relatively fewer studies have examined the moderating role of SES on the etiology of academic achievement. The present study seeks to explore the effects of this gene x SES interaction and a possible shared environment x SES interaction in a sample of twins participating in the Western Reserve Reading and Math Project. Data from five time points representing ages 8 to 15 with math achievement measures (N=222-528) and reading achievement measures (N=280-498) were used to assess the effects of SES (measured at the family, neighborhood, and school level) on estimates of the contribution of genetics, shared environment, and nonshared environment on variation in achievement. Significant moderation of genetics, shared environment, and non-shared environment were found for math achievement at ages 10.9 and 15.1 and for reading achievement at age 10.9. The significant effects were found in the opposite direction of those found for general cognitive ability: genetics accounted for more variation in the achievement outcome at the lowest end of SES than at the highest end of SES, and the shared environment accounted for more variation in achievement at the highest end of SES than at the lowest end of SES.