Dr. Thomas Bak of the Centre for Cognitive Ageing and Cognitive Epidemiology at the University of Edinburgh in Scotland, and colleagues examined standardized intelligence tests of 853 people who were born in 1936 and took part in the Scottish Mental Survey of 1947.
IQ scores taken by the study participants -- native English speakers -- at age 11 were compared with thinking tests taken by the study participants at age 73 that examined skills in reasoning, memory, speed of thinking and other brain functions.
The study, published in Annals of Neurology, found those who spoke two or more languages had significantly better cognition than would have been expected based on their childhood IQ scores.
"These findings are of considerable practical relevance," Bak said. "Millions of people around the world acquire their second language in later life. Our study shows that bilingualism, even when acquired in adulthood, may provide a small benefit to the ageing brain."