A study of nearly 13,000 twins from six countries around the world has found that up to 50 percent of their differences in motivation at school could be down to the genes they inherited from their parents.

The team assumed that the twins wouldn't differ much at all in their motivation at school, seeing as they shared the same environmental factors, such as parental attitude towards education, teachers, and facilities, and that these factors would have a greater influence on an individual's school experience than genetics. But it turns out that a person's genes might actually have a greater impact on their time at school than environmental factors.

"We had pretty consistent findings across these different countries with their different educational systems and different cultures. It was surprising," one of the team, Stephen Petrill from Ohio State University in the US, said in a press release. "Most personality variables have a genetic component, but to have nearly no shared environment component is unexpected. It was consistent across all six countries."

The study followed sets of twins aged from nine years old to 16, and living in the UK, Canada, Japan, Germany, Russia, and the US. The twins were asked to rate their ability in a range of different school subjects, including how they think they're performing now, and how they think they'll perform in the future. They were asked to rate how much they enjoyed doing things like reading, writing, and spelling. 

The researchers then compared the responses between the twins. Twins are great to use in genetic studies because they share half their genes if they're fraternal twins, and all their genetic make-up if they're identical twins. In the study, the extent to which the identical twins' answers were more closely matched than those of fraternal twins suggested to the researchers that genetics were at least partly at play in how the students responded to the questionnaire. 

Publishing in the journal Personality and Individual Differences, the team says, on average, 40 to 50 percent of the difference between the twins' motivation at school could be explained by genetics. They explain their results in the university press release:

"About the same percentage could be explained by what is called the twins' non-shared environment - for example, differential parenting or a teacher that one twin has but not the other. Only about 3 percent could be explained by their shared environment, such as their common family experience."

While the researchers are careful to note that this doesn't mean there's a 'gene for enjoying school', it could indicate that there are genetic factors at play in people that make them more likely to be motivated to learn. And knowing that perhaps it's harder for some kids to be motivated and it's not their fault could help teachers and parents handle this better.

"The knee-jerk reaction is to say someone is not properly motivating the student, or the child himself is responsible," Petrill said. "We found that there are personality differences that people inherit that have a major impact on motivation. That doesn't mean we don't try to encourage and inspire students, but we have to deal with the reality of why they're different."