Differences in Educational Achievement Owe More to Genetics than Environment

The degree to which students’ exam scores differ owes more to their genes than to their teachers, schools or family environments, according to new research from King’s College London published today in PLOS ONE.

The study, which took place in the UK, looked at students’ scores for their GCSE’s (General Certificate of Secondary Education), a UK-wide examination at the end of compulsory education at 16 years old.

The authors explain that the findings do not imply that educational achievement is genetically pre-determined, or that environmental interventions are not important, but rather that recognising the importance of children’s natural predispositions may help improve learning.

Researchers compared the GCSE exam scores of over 11,000 identical and non-identical 16 year old twins from the Medical Research Council (MRC) funded Twins Early Development Study (TEDS). Identical twins share 100% of their genes, whereas fraternal (non-identical) twins share on average only half of the genes that vary between people. Therefore, if identical twins’ exam scores are more alike than those of non-identical twins, the difference in exam scores between the two sets of twins is due to genetics, rather than environment.

The researchers found that for compulsory core subjects (English, Mathematics and Science), genetic differences between students explain on average 58% of the differences between GCSE scores. In contrast, 29% of the differences in core subject grades are due to shared environment–such as schools, neighbourhoods or families which twins share. The remaining differences in GCSE scores were explained by non-shared environment, unique to each individual.

Overall, science grades (such as Biology, Chemistry, Physics) were found to be more heritable than Humanities grades (such as Media Studies, Art, Music)–58% vs 42%, respectively.

Nicholas Shakeshaft, PhD student at the Institute of Psychiatry at King’s College London and lead author of the paper says: “Children differ in how easily they learn at school. Our research shows that differences in students’ educational achievement owe more to nature than nurture. Since we are studying whole populations, this does not mean that genetics explains 60% of an individual’s performance, but rather that genetics explains 60% of the differences between individuals, in the population as it exists at the moment. This means that heritability is not fixed–if environmental influences change, then the influence of genetics on educational achievement may change too.”

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