The Social Stratification of Environmental and Genetic Influences on Education: New Evidence Using a Register-Based Twin Sample

Abstract

The relative importance of genes and shared environmental influences on stratification outcomes has recently received much attention in the literature. We focus on education and the gene-environmental interplay. Specifically, we investigate whether-as proposed by the Scarr-Rowe hypothesis-genetic influences are more important in advantaged families. We argue that the social stratification of family environments affects children's chances to actualize their genetic potential. We hypothesize that advantaged families provide more child-specific inputs, which enhance genetic expression, whereas the rearing environments of children in disadvantaged families are less adapted to children's individual abilities, leading to a suppression of genetic potential. We test this relationship in Germany, which represents an interesting case due to its highly selective schooling system characterized by early tracking and the broad coverage of part-time schools. We use novel data from the TwinLife panel, a population-register-based sample of twins and their families. Results of ACE-variance decompositions support the Scarr-Rowe hypothesis: Shared environmental influences on education matter only in disadvantaged families, whereas genetic influences are more important in advantaged families. Our findings support the growing literature on the importance of the gene-environmental interplay and emphasize the role of the family environment as a trigger of differential genetic expression.

The German Twin Family Panel (TwinLife)

“…Concerning the final educational degree attained, Baier and Lang (2019) found a pattern following the Scarr-Rowe interaction hypothesis for the young adults in the oldest birth cohort of twins. Whereas genetic influences were more important for educational attainment of twins in families with higher educated parents, shared environmental influences mattered more if parental education was low.…”

An Introduction to the German Twin Family Panel (TwinLife)

“…Using a modified twin correlation model, they showed that the Scarr-Rowe hypothesis adequately describes the pattern of results in middle-childhood andto some degreein adolescence but not in adulthood in our German twin sample. Concerning the final educational degree attained, Baier and Lang (2019) found a pattern following the Scarr-Rowe hypothesis for the young adults in the oldest birth cohort of twins. Regarding the type of schooling track children attended, Schulz et al (2017) showed influences of parental socioeconomic resources over and above children's as well as parent's cognitive abilities.…”

Does Parental Separation Lower Genetic Influences on Children's School Performance?

“…The heritability estimations for different indicators of school performance provide insights about the role of genes and whether children can express their genetic potential related to education. However, when considering genetic influences relevant for education and its predictors, it is important to take into account that the relative importance of genes can depend on environmental conditions (e.g., Heath et al, 1985;Herd et al, 2019;Guo & Stearns, 2002;Turkheimer et al, 2003;Gottschling et al, 2019;Baier & Lang, 2019).…”

“…Research on IQ and educational outcomes has acknowledged the role of the family and considers parents social standing (e.g., Baier & Lang, 2019;Gottschling et al, 2019;Guo & Stearns, 2002;Turkheimer et al, 2003). This research is inspired by the Scarr-Rowe hypothesis, which states that genes relevant for cognitive ability are more important among advantaged children compared to disadvantaged children (Rowe et al, 1999;Scarr-Salapatek, 1971).…”

“…A major short coming of the previous literature is that children's advantage and disadvantage has almost exclusively been measured in terms of parental socioeconomic status, such as parental education, income, occupation, or summative indices (e.g., Baier & Lang, 2019;Conley et al, 2015;Guo & Stearns, 2002;Turkheimer et al, 2003). However, parental socioeconomic status alone may not adequately capture a key dimension of advantage and disadvantage during childhood (e.g., Esping-Andersen, 2007;McCall & Percheski, 2010;Western et al, 2016).…”