Speaking two languages from a very early age may keep the brain in good shape as we get older, a new study suggests.
The results show that adults in their 60s who have spoken two languages since childhood can switch from one task to another faster than people who speak just one language. What's more, bilingual older adults appear to require less "brain power" to carry out task switching, the study found.
As we age, the ability to perform complex tasks such as planning, scheduling and multitasking, and our ability to adapt to unfamiliar circumstances, both start to decline. Previous studies have suggested bilingualism may reduce this decline, but exactly what was happening in the brain to achieve this improvement was not clear.
During the new study, healthy adults ages 60 to 68, who were either bilingual or monolingual, had their brains scanned with functional magnetic resonance imaging (fMRI) while they completed one of three simple tasks. The first task required people to identify whether a shape was a circle or a square; the second task required subjects to identify the color of an object, red or blue; and the third task combined the first two.
Researchers referred to this final task as the "switch task" because people had to alternate between two decisions: color and shape.
Everyone in the study took longer to complete the switch task than to complete the other two tasks. But bilingual adults experienced less of a delay in their reaction time during the switch task compared to monolingual adults, the researchers said.
In addition, bilingual adults did not show as much activity in the frontal areas of their brains while completing the switch task compared to monolingual participants.
"This suggests that bilingual seniors use their brains more efficiently than monolingual seniors," said study researcher Brian Gold, of the University of Kentucky College of Medicine in Lexington.
Previous rsearch suggests that regions of the brain involved in switching from one language to another overlap with regions involved in switching from one task to another. So the act of regularly shifting from one language to a second language may strengthen the efficiency of regions involved in changing tasks, Gold said.
More research is needed to determine whether people who learn a second language later in life experience similar benefits.
A 2011 study found that bilingualism may protect against cognitive decline from Alzheimer's disease.
The new study is published in the Jan. 9 issue of the Journal of Neuroscience.