Speaking two languages may slow brain aging

Bilingualism has hit the headlines this week with the news that learning a second language might bring cognitive benefits in later life – even when that second language is acquired in adulthood.

The study was led by Dr. Thomas Bak at the University of Edinburgh, whose other work suggests that bilingualism might delay the onset of dementia. The current study looked at tests such as verbal fluency, in 835 native English-speakers aged 70 or older. Of these participants, 195 people had learnt a second language before 18, and 65 had learnt a second language after 18. The researchers compared people’s scores on the tests aged 70 with their IQ scores age 11.

The results showed that people who spoke a second language performed better on the tests than would be predicted from their early IQ results, relative to their monolingual peers. There were no differences between early versus late second language learners. In other words, learning a second language may slow brain aging.

These findings are important because they can help us answer the question of cause and effect. There are two possible reasons why bilinguals might show an advantage on cognitive tests. The first possibility is that people who have better cognitive ability to begin with are more likely to go on and learn another language. The second possibility is that learning a second language improves people’s cognitive ability. This study suggests that the second possibility is more likely – bilinguals did better on the tests than their childhood IQ scores would have predicted.

The fact that learning a language in adulthood seems to give the same advantage as learning a language in childhood is a highly relevant in the UK, where many people think that bilingualism only refers to people who grew up speaking two languages equally well. In fact, the advantages of bilingualism are relevant to anyone who uses a second language, whether they learnt it in the family, at school, or later on in the workplace. As Dr. Thomas Bak says, “Millions of people around the world acquire their second language later in life. Our study shows that bilingualism, even when acquired in adulthood, may benefit the aging brain.”

The study has been widely reported in the media including articles on the BBC health section, as well as daily news sites such as the Telegraph, the Times of India , and the Huffington Post , and science-specific sites such as Medical News Today, Science Daily, and
NHS Choices.

The full study “Does bilingualism influence cognitive aging?” was published online in the Annals of Neurology, on 2nd June 2014.