Genetics may account for as much as 60 percent of academic achievement, according to a new British study.
"Genes are important not just in educational achievement or intelligence but in a whole raft of other traits which contribute to how easy and enjoyable children find learning," said study co-lead author Eva Krapohl, a graduate student at King's College London in England.
The research looked at two different things: intelligence and educational achievement. In terms of intelligence, previous research has shown that "about half of the total variance of intelligence can be accounted for by genetic factors," said co-lead author Kaili Rimfeld, also a graduate student at the same college.
Other research has also shown that educational achievement is often an inherited trait, Rimfeld said. "The motivation for the current study was to investigate why educational achievement is so highly heritable," she said.
The researchers analyzed the results of education tests given to students in Great Britain when they finish compulsory education at age 16. The scientists focused on more than 13,000 twins -- both identical and nonidentical -- who'd also undergone tests designed to measure things like personality traits and behavioral problems. The twins were born between 1994 and 1996.
"Identical twins share 100 percent of the genes, and nonidentical twins, just as any other siblings, share 50 percent of the genes that differ between people," Krapohl said.
"By comparing identical and nonidentical twins, we can estimate the relative contributions of genetic and environmental influences. If identical twins are more similar on a particular trait -- like test scores -- than nonidentical twins, the differences between the two groups are due to genetics, rather than environment," she said.
The researchers found that genes had a greater influence on test scores in English, science and math than they did on other factors such as personality, behavior and health.
Still, the researchers said everything is linked: Genes play a big role in areas like personality, intelligence and behavior, and they all work together to affect test scores. The researchers cautioned that this doesn't mean a child of smart parents will automatically do well on tests, though.
The study "doesn't tell us anything about a single child," Rimfeld said. But she believes it does point toward the idea that kids vary greatly and need personalized education instead of "one size fits all."
Matt McGue, professor of psychology at the University of Minnesota, praised the study and said its findings reflect previous research into how genes and academic prowess are connected. The link may become even stronger as people get older: "There is now a growing literature indicating that as an individual ages, the importance of genetic influences on intelligence increases while the significance of environmental factors declines," he said.
McGue adds that the study doesn't get parents off the hook, since there's a lot more to doing well in school than having the right genes. Presumably, he said, "factors such as how parents support and encourage their children's academic success -- as well as the economic resources of the home -- are important," too.
The study appears in the Oct. 6-10 issue of Proceedings of the National Academy of Sciences.