A new study, published in the journal Annals of Neurology, suggests that learning a second language may slow down the age-related cognitive decline. This study was the first to examine whether learning a second language influences cognitive performance later in life while controlling for childhood intelligence.
Researchers from the Centre for Cognitive Aging and Cognitive Epidemiology at the University of Edinburgh in the UK assessed data from the Lothian Birth Cohort in 1936, which involved 835 native English speakers who were born and resided in Scotland in the UK. They were given mental skills tests at age 11 and again in their early 70s. Of the participants, 262 were able to speak at least two languages, with 195 of the participants learning a second language before age 18 (19 participants before the age of 11), and the rest after that age.
When comparing the cognitive abilities of the participants at an older age, the researchers found that individuals who were bilingual exceeded expectations - particularly in the areas of reading and general intelligence - compared with those who only spoke English.
"These findings are of considerable practical relevance. 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," study author Dr. Thomas Bak, from the Centre for Cognitive Aging and Cognitive Epidemiology at the University of Edinburgh said.
The researchers noted the limitations of the study. For example, the ability to speak a second language was determined by a questionnaire rather than aptitude tests, which could have influenced the results.
Also, only a few participants learned a second language before the age of 11, “so we could not study the classical cases of parallel, perfect, early acquisition of both languages”. However, they believe that this particular limitation was also a strength of the study, pointing out that millions of people learn a second language later in life, whether at school, university, work or as a result of migration.
This study is not a cause-and-effect study and requires more investigation on the links between learning multiple languages and cognitive ability.