The moderating role of SES on genetic differences in educational achievement in the Netherlands

Eveline L De Zeeuw,Catharina E M Van Beijsterveldt,Conor V Dolan,Gareth E Davies,Hamdi Mbarek,Dorret I Boomsma,Michael C Neale,Kees-Jan Kan,Jouke-Jan Hottenga

doi:10.1038/s41539-019-0052-2

Abstract

Parental socioeconomic status (SES) is a strong predictor of children’s educational achievement (EA), with an increasing effect throughout development. Inequality in educational outcomes between children from different SES backgrounds exists in all Western countries. It has been proposed that a cause of this inequality lies in the interplay between genetic effects and SES on EA, which might depend on society and the equality of the education system. This study adopted two approaches, a classical twin design and polygenic score (PGS) approach, to address the effect of parental SES on EA in a large sample of 12-year-old Dutch twin pairs (2479 MZ and 4450 DZ twin pairs with PGSs for educational attainment available in 2335 children) from the Netherlands Twin Register (NTR). The findings of this study indicated that average EA increased with increasing parental SES. The difference in EA between boys and girls became smaller in the higher SES groups. The classical twin design analyses based on genetic covariance structure modeling pointed to lower genetic, environmental, and thus phenotypic variation in EA at higher SES. Independent from a child’s PGS, parental SES predicted EA. However, the strength of the association between PGS and EA did not depend on parental SES. In a within-family design, the twin with a higher PGS scored higher on EA than the co-twin, demonstrating that the effect of the PGS on EA was at least partly independent from parental SES. To conclude, EA depended on SES both directly and indirectly, and SES moderated the additive genetic and environmental components of EA. Adding information from PGS, in addition to parental SES, improved the prediction of children’s EA.

Highlights

Parental socioeconomic status (SES), based on education level, occupation and income, is one of the strongest predictors of children’s educational achievement (EA).[1]
As expected, parental SES was found to be strongly associated with EA on a standardized test taken at the end of primary school
Differences between children in EA were attributable to genetic differences

Summary

Introduction

Parental socioeconomic status (SES), based on education level, occupation and income, is one of the strongest predictors of children’s educational achievement (EA).[1] Children in high SES families score higher on EA, and this SES-related gap increases throughout development, from a difference of ~0.5 SD at age 5. There may be direct causal effects of SES on EA, because high SES parents generally have more resources to invest in, and so to further, the EA of their offspring. Another cause of this inequality might be that high SES parents may both create a positive learning environment for their children, and transmit to their biological offspring genes that directly or indirectly facilitate EA.[10]

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