Twins study shows exam success is strongly influenced by DNA

In a study of more than 6,500 twins we've found that nature beats nurture when it comes to excelling in exams.

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In a study of more than 6,500 pairs of twins, researchers from our Department of Education and Kings College London, showed that more than half of the differences between pupils performance at GCSE can be explained by differences in genetics.

Genetics and GCSE results

The research found that although IQ showed the strongest relationship with exam scores other genetically influenced traits such as personality and behaviour also explained individual differences in achievement .

Intelligence accounted for more of the heritability of GCSE results than any other single domain but the joint contribution of pupils' self-belief, health, behaviour problems, personality, well-being, and perceptions of home and school, collectively accounted  for the same amount again.

Together with intelligence, these domains accounted for 75 per cent of the heritability of GCSE performance.

Heritability describes the extent to which differences between children can be ascribed to DNA differences, on average, in a particular population at a particular time.

The findings show that differences in how well children perform at exams are to a large extent explained by differences in their DNA and offer support for a stronger focus on personalised teaching and learning.

Twins

The study looked at 16-year-old twins who were part of the Medical Research Council (MRC) funded UK Twins Early Development Study (TEDS). The twins were assessed on a range of cognitive and non-cognitive measures, and the researchers had access to their GCSE (General Certificate of Secondary Education) results.

Identical twins share 100 per cent of their genes, and non-identical twins (just as any other siblings) share 50 per cent of the genes that vary between people. In this sample, both types of twin share their home and upbringing.

 By comparing identical and non-identical twins, the researchers were able to estimate the relative contributions of genetic and environmental factors.

Personalised teaching

Dr Kathryn Asbury, from our Department of Education's Psychology in Education Research Centre and one of the report authors, said: “This research makes crystal clear why there will never be a gene ‘for’ achievement.  How well young people perform in their GCSEs is bound up with their home lives, their school lives, their personalities and their health and well-being, as well as their cognitive abilities.  Understanding the genetic and environmental relationships between this broad array of pupils’ experiences and behaviour and their GCSE performance may eventually help us to personalise teaching and learning more effectively than we currently do.”

Published in the Proceedings of the National Academy of Sciences (PNAS), the study was led by Eva Krapohl and Kaili Rimfeld, from the Institute of Psychiatry, Psychology & Neuroscience at King’s College London.

Eva Krapohl said: “Previous work has already established that educational achievement is heritable. In this study, we wanted to find out why that is. What our study shows is that the heritability of educational achievement is much more than just intelligence – it is the combination of many traits which are all heritable to different extents."

Eva added: “It is important to point out that heritability does not mean that anything is set in stone. It simply means that children differ in how easy and enjoyable they find learning and that many of these differences are influenced by genetics.”

TEDS is supported by the UK Medical Research Council with additional funding from the National Institutes of Health.

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How well young people perform ... is bound up with their home lives, their school lives, their personalities and their health ... as well as their cognitive abilities.”

Dr Kathryn Asbury
Department of Education
Featured researcher
Dr Kathryn Asbury

Dr Kathryn Asbury

Lecturer

Research explores environmental influences on pupil achievement, wellbeing and behaviour using genetically sensitive designs.

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