“In previous studies, if bilinguals got dementia they got it 4 to 5
years later than monolinguals,” said author Dr. Thomas H. Bak of the
University of Edinburgh Center for Cognitive Aging and Cognitive
But it’s been hard to determine if mastering another tongue keeps
brains active longer or if people who learn another language start
off with different, or healthier, brains than those who don’t, he
“The big problem we didn’t know how to address was reverse
causality,” Bak told Reuters Health. “That is a very difficult
question to address, and we needed a very special population to do
In the new study, older bilinguals performed better on cognitive
tests than monolinguals, even when they had not scored better on
intelligence testing decades earlier. That means that at least in
part, learning another language does predict brain health in old
age, Bak said.
“Probably the causality is going in both directions, but we showed
that there is certainly an effect of bilingualism that cannot be
explained by previous differences,” he said.
He and his team used an existing data set including 853 Scottish
participants who were given an intelligence test in 1947 at age 11,
and retested between 2008 and 2010 while in their seventies.
Of those, 262 had learned a language in addition to English, most
before age 18, and only 90 were actively using the second language
Even taking early intelligence scores into account, people who had
learned a second language scored higher on reading, verbal fluency
and general intelligence in old age than those who never did.
The relationship was the same for the 65 people who learned their
second language after age 18, and seemed to get stronger with third,
fourth and fifth languages, according to results in the Annals of
“I think it’s a study that could only have been done really with
this cohort, this Scottish group,” Fergus Craik said. “I’m not
surprised at the effect but it’s excellent to have this evidence.”
Craik, who was not part of the new study, is a senior scientist at
the Rotman Research Institute at the Baycrest academic health
sciences center, affiliated with the University of Toronto.
There’s always a question of ‘which comes first,” bilingualism or
better brains, Craik told Reuters Health.
[to top of second column]
But people by and large don’t become bilingual because they are
interested or bright, but because they have to, he said.
“I don’t think there’s anything magic about learning languages,” Bak
said. “Both mental and physical activity throughout the life are
protective, and learning language is a very good form of brain
Learning a second language improves certain mental functions, mostly
those connected to the frontal lobe of the brain, but not all
functions, Craik said.
“It does improve fluid intelligence and ‘executive functioning,’
because you have to control the two languages you know,” he said.
“While you communicate in one language you’ve got to manage and
control the other language.”
Speaking more than two languages may improve thinking even more, but
that’s still a bit of an open question, Craik said.
For people who are beyond school age but are still interested in
learning a second language, these results should be encouraging, Bak
said. He wouldn’t recommend that people worried about dementia go
out and learn another language as a precaution, but for those who
are interested in language there may be unexpected benefits.
“I would not push it forward but if you leave the chance of many
languages being spoken in the house, it could be great brain
training and great fun,” he said.
Annals of Neurology, online June 2, 2014.
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