For some people learning a second language has no mystery; For others, on the other hand, it is an arduous task, which does not always end in a successful result. For those who are in the second case: according to a study carried out by researchers at the University of Washington (USA) and published by the journal PNAS , in large part the problem could be attributed to brain and genetic factors – specifically , to variants of a gene called COMT–, which together account for 46% of the reason why some students perform better than others in language classes.
“Our study shows for the first time that the COMT gene variants are related to changes in the white matter of the brain – a whitish tissue that is part of the central nervous system – that are the result of learning,” explains Ping Mamiya, researcher from the Institute for Learning and Brain Sciences (I-LABS) at the University of Washington and lead author of this research.
“We all know that human learning is very complex and that it is influenced by a large number of factors,” says Patricia Kuhl, co-director of I-LABS and co-author of the study. “Learning a second language as adults is difficult, and we believe that studying how people learn something difficult is a good way to unravel the interactions between genes and the brain in learning,” he continues.
The research team recruited 79 volunteers, all of them Chinese students in their early twenties who had just arrived in the United States to study at the University of Washington. All of them had passed the minimum level of English required by the educational center.
Among the students, 44 immediately underwent an intensive three-week course to improve their level of English; and in that period and for eight days later, the scientists performed brain scans, as well as the 35 of the control group who had not attended intensive classes, with a technique called diffusion tensor magnetic resonance (DTI), which gives clues about the structure of brain connections.
The results of these scans suggest that the white matter began to change as early as the first day of the intensive course , increasing the connectivity of the brain’s language circuits compared to those who had not signed up for the classes. This increase occurred only over the course of the three weeks of intensive training.
Thanks to the DNA samples taken before intensive classes and the different increases in brain connections they saw in the students’ scans, the scientists saw that two variants of the COMT gene (methionine / valine or valine / valine) were linked to that there was a greater increase in the connectivity of the brain areas that affect language ; contrary to what happened with the students who had a third COMT genotype (methionine / methionine), whose white matter practically did not change in response to the experience of these intensive language courses.
