According to a large new study of twins, genetics explains more than 60% of individual differences in school achievement.
Rimfeld et al use twin analyses and genome-wide polygenic score analyses of longitudinal data from the Twins Early Development Study from age 7 to age 16, including GCSE scores, to investigate three issues — the stability of general educational achievement, the stability of achievement in specific subjects, and the contribution of general cognitive ability to the stability of educational achievement. Image credit: Andrew Tan.
For many years, research has linked educational achievement to life trajectories, such as occupational status, health or happiness.
But if performing well in school predicts better life outcomes, what predicts how well someone will do throughout school?
“Around two-thirds of individual differences in school achievement are explained by differences in children’s DNA,” said Dr. Margherita Malanchini, a psychology postdoctoral fellow at the Population Research Center at the University of Texas at Austin.
“But less is known about how these factors contribute to an individual’s academic success overtime.”
Dr. Malanchini and co-authors analyzed test scores from primary through the end of compulsory education of more than 6,000 pairs of twins.
They found educational achievement to be highly stable throughout schooling, meaning that most students who started off well in primary school continued to do well until graduation.
Genetic factors explained about 70% of this stability, while the twins shared environment contributed to about 25%, and their non-shared environment, such as different friends or teachers, contributed to the remaining 5%.
“That’s not to say that an individual was simply born smart,” the scientists said.
“Even after accounting for intelligence, genes still explained about 60% of the continuity of academic achievement.”
“Academic achievement is driven by a range of cognitive and non-cognitive traits,” Dr. Malanchini said.
“Previously, studies have linked it to personality, behavioral problems, motivation, health and many other factors that are partly heritable.”
However, at times grades did change, such as a drop in grades between primary and secondary school.
Those changes can be explained largely by non-shared environmental factors.
“Our findings should provide additional motivation to identify children in need of interventions as early as possible, as the problems are likely to remain throughout the school years,” said Dr. Kaili Rimfeld, a postdoctoral researcher at the Institute of Psychiatry, Psychology and Neuroscience at King’s College London.
The study was published in the journal Science of Learning.
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Kaili Rimfeld et al. 2018. The stability of educational achievement across school years is largely explained by genetic factors. npj Science of Learning 3, article number: 16; doi: 10.1038/s41539-018-0030-0
