Exploring individual differences in academic achievement
: Genetics, personality and the school environment

Student thesis: Doctoral ThesisDoctor of Philosophy


Education is one of society’s biggest investments. It aims to equip students with the skills and knowledge necessary to make their way in the world. Students’ performance at school (educational achievement) can set them on very different life trajectories. Furthermore, differences in academic achievement are linked to variation in health, wellbeing, income and even mortality. Therefore, it is of societal importance to understand why individuals differ in academic achievement, and to explore their causes and correlates to improve education.
Differences in educational achievement are often attributed to the environment, for example the quality of a school a child attends. However, decades of behavioural genetic literature has shown that achievement is also substantially influenced by genetic factors. In order to increase understanding of the genetic and environmental influences on academic achievement, this thesis explores: the extent to which genetic variants associated with educational attainment explain differences in personality, and their relationship with educational achievement (Chapter 2); average DNA and achievement differences between students attending selective and non-selective schools (Chapter 3); the influence of school quality on educational achievement and student wellbeing (Chapter 4); and the genetic architecture of attainment and achievement beyond compulsory education into university (Chapter 5).
This thesis uses data from the Twins Early Development Study (TEDS). TEDS is a UK-representative sample of over 10,000 twin pairs followed longitudinally from age two to age 22, with a genotyped subsample of approximately 6,000 unrelated individuals. This thesis capitalises on both twin analysis and DNA-based methods to investigate the aetiology of achievement during secondary school and into university.
This thesis provides evidence that: 1) genetic effects of educational attainment relate to personality and motivation, and explain part of the covariance between personality and achievement; 2) genetic and achievement differences between students attending different school types are primarily due to the heritable characteristics involved in pupil admission, including general cognitive ability, socioeconomic status and prior achievement; 3) independently-rated school quality has little influence on educational achievement or student wellbeing during secondary school; and 4) genetic influences on achievement and attainment extend beyond compulsory education into university.
A discussion of these findings and their implications for teachers, policy-makers and parents is provided in the final chapter (Chapter 6), along with the conclusions that can be drawn from this body of work.
Date of Award2018
Original languageEnglish
Awarding Institution
  • King's College London
SupervisorRobert Plomin (Supervisor)

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