If you sailed through school with high grades and perfect test scores, you probably did it with traits beyond sheer smarts. A new study of more than 6000 pairs of twins finds that academic achievement is influenced by genes affecting motivation, personality, confidence, and dozens of other traits, in addition to those that shape intelligence. The results may lead to new ways to improve childhood education.
“I think this is going to end up being a really classic paper in the literature,” says psychologist Lee Thompson of Case Western Reserve University in Cleveland, Ohio, who has studied the genetics of cognitive skills and who was not involved in the work. “It’s a really firm foundation from which we can build on.”
Researchers have previously shown that a person’s IQ is highly influenced by genetic factors, and have even identified certain genes that play a role. They’ve also shown that performance in school has genetic factors. But it’s been unclear whether the same genes that influence IQ also influence grades and test scores.
In the new study, researchers at King’s College London turned to a cohort of more than 11,000 pairs of both identical and nonidentical twins born in the United Kingdom between 1994 and 1996. Rather than focus solely on IQ, as many previous studies had, the scientists analyzed 83 different traits, which had been reported on questionnaires that the twins, at age 16, and their parents filled out. The traits ranged from measures of health and overall happiness to ratings of how much each teen liked school and how hard they worked. Then, the researchers collected data on how well each individual scored on the General Certificate of Secondary Education (GCSE) exam, an exam that all students in the United Kingdom must take and which is used for admission to advanced classes or colleges.
The team found nine general groups of traits that were all highly hereditary—the identical twins were more likely to share the traits than nonidentical twins—and also correlated with performance on the GCSE. Not only were traits other than intelligence correlated with GCSE scores, but these other traits also explained more than half of the total genetic basis for the test scores.
In all, about 62% of the individual differences in academic achievement—at least when it came to GCSE scores—could be attributed to genetic factors, a number similar to previous studies’ findings, the team reports online today in the Proceedings of the National Academy of Sciences.
“It’s really important to understand why children differ in academic achievement,” says developmental psychologist Kaili Rimfeld of King’s College London, an author of the new paper. “These twin studies show that there’s a genetic basis for the differences in how easy or enjoyable children find learning.” Understanding that there’s a genetic basis for why people differ in not only intelligence, but also their drive to learn, she says, underscores the need for personalized classrooms where students can learn in different ways—from computer programs to hands-on projects—that are most fitted to their own personalities.
The results, Thompson points out, would likely differ in less-developed countries where children don’t have equal access to education; academic achievement in these places is shaped more by opportunities than genetics. And the new study gives little information on what the genes might be that influence test scores. “Each one of these traits is very complex,” she says, “so we’re talking about hundreds of genes that are acting together.” Future studies, she says, may be able to shed light on specific genes that affect academic achievement, which could help diagnose or treat learning disabilities.
*Correction, 7 October, 12:20 p.m.: This item originally stated that 62% of academic achievement could be attributed to genetic factors. In fact, the research showed that 62% of the differences between individual students' GCSE scores were attributed to genetic factors.