Why is educational achievement heritable?

New research, led by King's College London finds that the high heritability of exam grades reflects many genetically influenced traits such as personality, behaviour problems, and self-efficacy and not just intelligence.

The study, published today in the Proceedings of the National Academy of Sciences (PNAS), looked at 13,306 twins at age 16 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) scores.

In total, 83 scales were condensed into nine domains: intelligence, self-efficacy (confidence in one's own academic ability), personality, well-being, home environment, school environment, health, parent-reported behaviour problems and child reported behaviour problems.

Identical twins share 100% of their genes, and non-identical twins (just as any other siblings) share 50% of the genes that vary between people. Twin pairs share the same environment (family, schools, teachers etc). By comparing identical and non-identical twins, the researchers were able to estimate the relative contributions of genetic and environmental factors. So, if overall, identical twins are more similar on a particular trait than non-identical twins, the differences between the two groups are due to genetics, rather than environment.

Eva Krapohl, joint first author of the study, from the Institute of Psychiatry, Psychology & Neuroscience (IoPPN) at King's, says: "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.

"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 much of these differences are influenced by genetics."

The researchers found that the heritability of GCSE scores was 62%. Individual traits were between 35% and 58% heritable, with intelligence being the most highly heritable. Together, the nine domains accounted for 75% of the heritability of GCSE scores.

Heritability is a population statistic which does not provide any information at an individual level. It describes the extent to which differences between children can be ascribed to DNA differences, on average, in a particular population at a particular time.

Kaili Rimfeld, joint-lead author, also from the IoPPN at King's says: "No policy implications necessarily follow from finding that genetics differences influence educational achievement, because policy depends on values and knowledge. However, our findings support the idea that a more personalized approach to learning may be more successful than a one size fits all approach. Finding that educational achievement is heritable certainly does not mean that teachers, parents or schools aren't important. Education is more than what happens to a child passively; children are active participants in selecting, modifying, and creating their experiences – much of which is linked to their genetic propensities, known in genetics as genotype–environment correlation."

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

For a copy of the paper, or interviews with the authors, please contact Seil Collins, Press Officer, Institute of Psychiatry, Psychology & Neuroscience (IoPPN) at King's College London seil.collins@kcl.ac.uk / (+44) 0207 848 5377 / (+44) 07718 697 176

Paper reference: Krapohl, E. et al. "The high heritability of educational achievement reflects many genetically influenced traits, not just intelligence" published in PNAS.

About TEDS: http://www.teds.ac.uk/

About King's College London

King's College London is one of the top 20 universities in the world (2014/15 QS World University Rankings) and the fourth oldest in England. It is The Sunday Times 'Best University for Graduate Employment 2012/13'. King's has nearly 26,000 students (of whom more than 10,600 are graduate students) from some 140 countries worldwide, and more than 7,000 staff. The College is in the second phase of a £1 billion redevelopment programme which is transforming its estate.

King's has an outstanding reputation for providing world-class teaching and cutting-edge research. In the 2008 Research Assessment Exercise for British universities, 23 departments were ranked in the top quartile of British universities; over half of our academic staff work in departments that are in the top 10 per cent in the UK in their field and can thus be classed as world leading. The College is in the top seven UK universities for research earnings and has an overall annual income of nearly £590 million.

King's has a particularly distinguished reputation in the humanities, law, the sciences (including a wide range of health areas such as psychiatry, medicine, nursing and dentistry) and social sciences including international affairs. It has played a major role in many of the advances that have shaped modern life, such as the discovery of the structure of DNA and research that led to the development of radio, television, mobile phones and radar.

King's College London and Guy's and St Thomas', King's College Hospital and South London and Maudsley NHS Foundation Trusts are part of King's Health Partners. King's Health Partners Academic Health Sciences Centre (AHSC) is a pioneering global collaboration between one of the world's leading research-led universities and three of London's most successful NHS Foundation Trusts, including leading teaching hospitals and comprehensive mental health services. For more information, visit: http://www.kingshealthpartners.org.

King's fundraising campaign – World questions|King's answers – created to address some of the most pressing challenges facing humanity has reached its £500 million target 18 months ahead of schedule. The College is now aiming to build on this success and raise a further £100 million by the end of 2015, to fund vital research, deliver innovative new treatments and to support scholarships. The campaign's five priority areas are neuroscience and mental health, leadership and society, cancer, global power and children's health. More information about the campaign is available at http://www.kcl.ac.uk/kingsanswers.