This report used a population-representative longitudinal twin study with two birth cohorts to explore the association between intelligence and education by understanding how genetic and environmental influences on intelligence moderate genetic and environmental influences on school grades and educational attainment. Nonshared environmental influences on grades were strong when IQ was low, but decreased across the range of IQ. Shared environmental influences common to age 24 educational attainment and age 17 IQ were strong when IQ was low, but genetic influences common to IQ and education were strong when IQ was high. These results suggest that the causal mechanisms linking educational variables with intelligence differ for people with different levels of intelligence.
Bibliographical noteFunding Information:
This research was supported by US Public Health Service Grants #AA00175, DA 13240, and DA 05147. Wendy Johnson holds a Research Council of the United Kingdom Fellowship. Wendy Johnson holds a RCUK Fellowship. She and Ian Deary are members of the MRC Centre for Cognitive Ageing and Cognitive Epidemiology, which is supported by the BBSRC, EPSRC, and MRC as part of the cross-council Health and Well-being Initiative. We thank the twins and their families and the recruiting, interviewing, data management, and lab staffs of the Minnesota Twin Family Study.
- Educational attainment
- Gene-environment correlation and interaction
- Genetic and environmental influences
- Grade point average