Mind your language: The benefits of bilingualism

Brussels is officially a bilingual city, but wherever you go in Belgium you’ll find people easily moving from one language to another. This makes the country the ideal place to study how the brain handles languages, and in particular whether bilingualism makes the mind more agile.

This idea that bilingual people have a cognitive advantage over monolinguals was first investigated in the 1980s. Bilinguals were expected to perform better in tests related to language use, but it was a surprise when they had better scores in more general tests of cognitive ability.

For example, someone might be shown red and green dots on the left or the right side of a computer screen, and asked to identify the colour – not the position – by pressing as quickly and as accurately as possible on a left button for green and a right button for red. The test doesn’t involve language, but bilingual people still appeared to have a very slight advantage.

“They are talking about effects that are about 50 milliseconds,” says Evy Woumans, a researcher in Ghent University’s department of experimental psychology, adding that this small difference is significant for scientists. “But I wouldn’t really say that it has an effect on real life.”

When a multilingual person thinks of an object, its names in all the languages are present in the mind. In order to speak just one language, the others need to be held back.

One theory is that this inhibition mechanism may be connected to the mechanism used in cognitive control tasks. In other words, the ability to ignore the position of a green dot and respond quickly to its colour might involve the same mechanism as ignoring a word in your mother tongue and speaking it in a second language.

But as researchers set out to explore this phenomenon, many found the bilingual advantage inconsistent, or absent altogether. Esli Struys, now an assistant professor in linguistics at the Free University of Brussels (VUB), was one of those who drew a blank.

In 2010 he began his PhD with the intention of repeating an earlier study and then looking for differences between bilinguals. When the bilingual advantage didn’t appear, he was stuck. But he was also making brain scans, and there he found clear differences. “If you look at the structure of bilingual brains, they are differently wired,” he says. Whether these differences change behaviour is another matter. “There are so many things that may have an effect on behavioural measures, and bilingualism is only one of them.”

Alzheimer's

Some of these confounding factors were built into the early studies. For example, one form of the bilingual advantage is that elderly bilingual people seem to be more resistant to the symptoms of Alzheimer’s disease than monolingual people. Yet the studies that found this had looked at bilinguals who were late immigrants to the country in question. “If you, as a 40-year-old, have the courage to go to another country and learn another language, then it could be something intrinsic to you,” explains Woumans.

Repeating the study in Belgium made it possible to reduce this possible confusion. Woumans and her colleagues looked at people with probable Alzheimer’s disease arriving in hospitals in Ghent and Brussels. Patients’ life histories in both places were similar, but in Ghent the researchers could look at monolingual Dutch-speakers while in Brussels they found Dutch-speakers who regularly spoke French. And the bilingual advantage was still there, with symptoms of dementia appearing on average 4.6 years later in the bilingual patients.

Eliminating the difference between monolingual and bilingual groups was also the aim of a study Woumans, Struys and others carried out in a bilingual kindergarten. Children were tested when they started school, as monolinguals, then a year later after receiving half their education in French and half in Dutch.

“We wanted to see how the bilinguals compared to their own monolingual selves,” Woumans says, though a similar group from a monolingual kindergarten were also included. At the beginning, both groups performed equally on tests for intelligence, cognitive control and verbal fluency. A year on, both had improved equally in verbal fluency and cognitive control, so the traditional cognitive advantage wasn’t present. But children attending bilingual kindergarten showed greater improvement in the intelligence tests.

Effect on brain function

While this is a much more tangible advantage than the milliseconds gained in cognitive control tests, Woumans is cautious about the result. “If we tested them again when they’re eight years old, the advantage may have disappeared. It might just be a speeding up of cognitive development, but then other children catch up.”

She is still working on the effect of bilingual education, but her next big project is to lead a major international study looking for the bilingual advantage. It aims to involve about 15 laboratories, each recruiting 200 participants who will go through identical language proficiency and cognitive ability tests. While it may not settle the question once and for all, it will provide a wealth of new data.

For Struys, the priority for future research is to look at what kind of bilingual experience has an effect on brain function. “Some people switch frequently between languages, and others do not, and this pattern of languages will have an effect.”

There are studies planned to look at how this language switching occurs and the effect it has, both in regular bilinguals and in the extreme case of interpreters, who use two languages almost simultaneously.

Whether the languages spoken by the bilinguals makes a difference has yet to be studied in detail, but Woumans has a hunch that similarity is the key. “I think more similar languages will require more control to keep them apart.” So should someone learn a second language in the hope of getting a cognitive advantage? Woumans thinks this question misses the most important point. “Even if there’s nothing else going on, you are still left with a second language, which is an advantage in itself.”

This article first appeared in The Bulletin Spring 2017. Browse the magazine here, pick up a copy in newsagents or subscribe now