Malanchini and Kaili Rimfeld, a postdoctoral researcher at the Institute of Psychiatry, Psychology, and Neuroscience at King’s College London, analyzed test scores from primary through the end of compulsory education of more than 6,000 pairs of twins.
Researchers 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 percent of this stability, while the twins shared environment contributed to about 25 percent, and their non-shared environment, such as different friends or teachers, contributed to the remaining 5 percent.
That’s not to say that an individual was simply born smart, researchers explain. Even after accounting for intelligence, genes still explained about 60 percent of the continuity of academic achievement.
“Academic achievement is driven by a range of cognitive and noncognitive traits,” Malanchini says. “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, researchers said, can be explained largely by non-shared environmental factors.
“Genes don’t work in isolation, and genetic predisposition combines and interacts with environmental exposure in contributing to differences in observed educational outcomes,” Malanchini says. “In the future, we might be able to combine the prediction of genetic and environmental risk to identify children in need of interventions as early as possible, and therefore help those who need it most.”