When It Comes To Standardized Test Scores, Genetics More Important Than Environmental Factors, Study Says

Genes May Explain Greatest Influence On School Test Scores
In a study analyzing twins, investigators found genes more responsible for variability in test scores. CC By 2.0

Science in recent years has provided a saliently satisfying answer to the age-old debate in human development about nature versus nurture. Equipped with advanced computing and brain scanning tools, investigators assert that environmental pressures cause epigenetic changes brought by altered expressions of a given gene — with so much more in play, than previously thought. Now, however, a new study from the UK shows genetics to be the single greatest influencer in a child’s standardized test scores at school.

In a paper published earlier this month, the investigators compared national standardized tests taken throughout the country at age 16, analyzing data from more than 11,000 identical and fraternal twin pairs. Given that identical twins share an identical genome, investigators compared sets of identical twins with fraternal twins to determine influence due solely to DNA. In required subjects such as English, math, and science, genetic variance among the students explained on average 58 percent of the variability in test scores. Conversely, they figured that 29 percent of the variability in test scores was attributable to similar environments such as homes, schools, and neighborhoods.

Interestingly, science grades were found to be more “heritable” than those for humanities, at 58 percent to 42 percent respectively, according to investigator Nicholas Shakeshaft, a doctoral candidate at King’s College London.

“Our research shows that differences in students' educational achievement owe more to nature than nurture,” Shakeshaft said in a statement. “Since we are studying whole populations, this does not mean that genetics explains 60 percent of an individual's performance, but rather that genetics explains 60 percent of the differences between individuals, in the population as it exists at the moment. This means that heritability is not fixed — if environmental influences change, then the influence of genetics on educational achievement may change, too."

However, the investigators quickly put the kibosh on possible misinterpretations of their work, denying the genetic predetermination of scholastic ability. Robert Plomin, director of the school’s Institute of Psychiatry, said the findings carry “no necessary or specific implications for education policies.” Rather, the study should be employed to better recognize natural predispositions among schoolchildren as a tool for educational improvement.

“It's important to recognize the major role that genetics plays in children's educational achievement,” he said. “It means that educational systems which are sensitive to children's individual abilities and needs, which are derived in part from their genetic predispositions, might improve educational achievement."

Commenting on the study in a press release, Michael O’Donovan, from the UK’s Neurosciences and Mental Health board at the Medical Research Council, likewise attempts to dissuade potential misuse of the study conclusions. "The findings from this substantial cohort add to a convincing body of evidence that genes influence characteristics that are ultimately reflected in educational performance,” he said. “But it is equally important to stress that the researchers found that environments for students are also important and that the study does not imply that improvements in education will not have important benefits.”

Donovan said the publicly funded study highlights the importance of studying the interplay between genes and our environments, and how both shape the course of the human life.

Source: Shakeshaft N, Plomin R. Differences In Educational Achievement Owe More To Genetics Than Environment. PLoS One. 2013.

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