Genetic and environmental factors explain differences in school performance
Find out how genes affect learning in our new research article "The stability of educational achievement across school years is largely explained by genetic factors" published by npj Science of Learning
Our new article "The stability of educational achievement across school years is largely explained by genetic factors" was published by npj Science of Learning and the Nature team were curious to know more. My colleagues Margherita Malanchini, Eva Krapohl, Laurie Hannigan, Philip Dale, Robert Plomin and myself are based at King's College London in the United Kingdom and the University of New Mexico in the United States of America. We are excited to share our insights to how genes influence individual academic achievement.
What was the main aim of your research and why did you decide to investigate this?
School achievement is important to society and to children as individuals because exam results during compulsory education push children to different lifelong trajectories such as further education and occupations. Individual differences in school achievement are explained by both genetic and environmental factors. Research has shown that the heritability of school achievement is around 60 per cent meaning that around two thirds of individual differences in school achievement are explained by the inherited differences in children’s DNA sequence. However, much less is known about developmental continuity and change of school performance, that is, do the same or different genetic and environmental factors explain individual differences in school performance and what factors contribute to stability of change of performance at schools. Here we used both the twin design and DNA-based methods to answer these questions.
What were the key findings from the study?
The study had three major findings. First, we found that differences between children in educational achievement are highly stable throughout schooling, from primary school to the end of compulsory education. Since we know from previous studies, including those from our research group, that genetic factors play a major role in explaining differences between students in school achievement, our second goal was to investigate to what extent genetic and environmental factors contribute to this observed stability in educational achievement. We found that genetic differences between children were the main contributor to the stability of educational achievement over the course of compulsory education. Environmental factors that are shared between family members, also contributed to the stability of achievement, but to a lesser extent. Third, we investigated whether differences between children in intelligence could account for the observed stability of educational achievement. We found that, although intelligence accounted for part of these genetic effects, the stability of achievement remained largely driven by genetic factors even after accounting for intelligence.
How can genes influence an individual’s record of achievement, given the other variables people are exposed to in life?
Finding high heritability of educational achievement means that differences in how well children perform in exams are to a large extent explained by differences in their DNA. Importantly, it does not mean that genetics explain around 60 per cent of a single child’s school achievement. Heritability is a population statistic that denotes the proportion of individual differences between children that is explained by differences in their genome in a particular population at a particular time.
It is important to consider what drives this high heritability of educational achievement. We have previously shown that the high heritability of educational achievement is explained by a range of cognitive and non-cognitive traits, such as personality, behavioral problems, motivation, health, in addition to intelligence, all of these factors are also highly heritable.
Genes and environment do not act in isolation; differences between individuals on any complex trait (such as educational achievement) are the result of the complex interplay between genes and environment. Importantly, education is more than what happens to a child passively, children are active participants in selecting, modifying and creating experiences that are matched to their genetic predispositions. In genetics, this is known as ‘gene-environment correlation.’
Will a simple DNA test in the future inform how individuals might perform throughout their educational life?
In our study, we found that a polygenic score constructed aggregating many genetic variants of small effect obtained from a genome-wide association study (GWAS) of educational attainment predicted differences between students in achievement at all ages. We also found that these genetic effects were mostly stable. Our research highlights the importance of considering genetic differences between students in educational research. In fact, too often studies have investigated the processes that might lead to differentiation in educational achievement without directly considering genetic predisposition. However, the pathway from genotype to observed behavioral differences between people is likely to be long and winding, and to be moderated and/or mediated by environmental, developmental and biological processes. So a simple DNA test, although predictive, is unlikely to be the only information we need or want to predict how individuals will perform throughout their educational life. A fundamental next step is to identify how genetic predisposition results in observed differences between people in educational achievement, which is part of our future research goals.
What’s the bigger picture of your research findings?
Children are different in school achievement and these differences are to a large extent explained by genetic differences between them. School achievement is highly heritable across compulsory education and across different subjects children study at school. Our finding of genetically driven stability of educational achievement should provide additional motivation to identify children in need of interventions as early as possible, as the problems are likely to remain throughout the school years. Prediction, using both DNA based methods and environmental risk factors, might in the future provide a tool to identify children with educational problems very early in life and aid in providing both individualized prevention and individualized learning programs.
What is the future for the field?
Our study, establishing that the genetic effects on variation in educational achievement are largely stable throughout schooling, presents a foundation for the investigation of which environmental and biological processes might mediate or moderate the prediction from differences in DNA to observed differences in educational performance. Identifying these processes is likely to help refine targets for interventions aimed at fostering learning and helping children who struggle the most. Intervention science has too often ignored the fact that some children are likely to find learning experiences more challenging than others, partly due to their genetic predisposition, which is no fault of their own. Our research highlights the importance of considering genetic differences between children in the development of future intervention models. This is already happening in other fields such as medicine, where genetic differences between patients are considered, along with multiple other factors, when predicting treatment responses. Adopting similarly refined, yet holistic approaches in the field of education and learning, is likely to improve the effectiveness of learning interventions, consequently improving the educational and life outcomes for all children, and particularly for those who struggle the most.