In a large UK study of teenage twins, researchers found that differences in exam grades owed more to genes than family environment, schools and teachers. In math, English and science, genes accounted for nearly 60% of the differences, they found.

The team from King's College London reported the results of their study, which involved over 11,000 identical and non-identical 16-year-old twins online in a recent edition of PLOS ONE.

First author Nicholas Shakeshaft, who is working toward a PhD at King's Institute of Psychiatry, says:

"Children differ in how easily they learn at school. Our research shows that differences in students' educational achievement owe more to nature than nurture."

However, he and his colleagues are keen to point out that their findings do not suggest educational achievement is genetically predetermined, nor that family, teachers and schools are unimportant.

Rather, the study highlights the need to recognize the importance of children's natural predispositions in ability to learn.

Study compared identical with non-identical twins

The team sourced their data from the Twins Early Development Study (TEDS), which is funded by the Medical Research Council (MRC) and based at King's College London. TEDS aims to increase understanding of how nature and nurture - our genes and our environment - influence learning, thinking and behavior.

In their analysis, the team examined results of the twins' GCSE (General Certificate of Secondary Education) exams. GCSEs are national exams that UK students take in the final year of their compulsory education at age 16.

Identical twins share 100% of their genes, while non-identical, or fraternal twins, share on average around 50% of the genes that vary between people.

Exam scores were more similar for identical twins

The analysis showed that the exam scores of identical twins were more similar than the exam scores of non-identical twins, suggesting that the differences in educational achievement was more due to genetics than environment.

The researchers also found the results varied, according to types of subjects:

  • For compulsory core subjects of English, science and mathematics, differences in genes accounted on average for 58% of the differences in exam scores.
  • In contrast, shared environment - such as having the same neighborhood, attending the same school, being in the same family - only accounted for 29% of the differences in these core subjects.
  • Overall, genes appeared to have a bigger influence on exam results for science (i.e. biology, chemistry and physics), where they accounted for 58% of the differences, than humanities (i.e. art, media studies, music), where they accounted for 42% of the differences, on average.
  • The remaining differences were explained by non-shared environment, factors that are unique to each person, say the researchers.

Results do not mean genetics rule 60% of educational performance

Mr. Shakeshaft says it is important to note that these results do not imply that in each person the influence of their genes is nearly 60% and cannot be changed. This was a population study, as he explains:

"Since we are studying whole populations, this does not mean that genetics explains 60% of an individual's performance, but rather that genetics explains 60% of the differences between individuals, in the population as it exists at the moment."

"This means that heritability is not fixed," he adds, "if environmental influences change, then the influence of genetics on educational achievement may change too."

Prof. Robert Plomin, senior study author who is also director of TEDS, says:

"Whilst these findings have no necessary or specific implications for educational policies, it's important to recognize the major role that genetics plays in children's educational achievement."

He says the findings imply education systems that are sensitive to individual children's needs may help them perform better at school.

Professor Michael O'Donovan, from the MRC's Neurosciences and Mental Health board at the Medical Research Council, says the study adds to a "convincing body of evidence" that shows genes influence factors that make a difference to educational performance, and he notes:

"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. For individuals living in the best and worst environments, this exposure is likely to make more of a difference to their educational prospects than their genes."

Like the authors, he says further research is needed to find out what these results mean for educational policies.

In August 2012, researchers from the University of North Texas presented the American Psychological Association's 120th Annual Convention, with the result of a study where they had found physically fit school kids scored higher on reading and math.

They suggested that having a healthy heart and lungs may be one of the most important factors for middle school students to achieve good grades in those subjects.