研究:双语者的认知能力更好

Older adults who've spoken two languages since childhood have a distinct cognitive edge over their monolingual peers, according to a new study.

Previous studies have shown bilingualism seems to favor the development of heightened mental skills. The new research, published in Neuroscience, provides evidence of that cognitive advantage among older, bilingual adults.

Subjects were divided into three groups: bilingual seniors, monolingual seniors and younger adults and instructed to sort colors and shapes in a series of simple cognitive exercises. The researchers used a brain imaging technique  to compare how well the subjects switched between mental tasks. 

Brian Gold, a neuroscientist at the University of Kentucky College of Medicine and lead author of the study, found the results showed different patterns of brain activity in the frontal part of the brain associated with the tasks. 

“We found that seniors who are bilingual are able to activate their brain with a magnitude closer to young subjects," Gold says. "So they do not need to expend as much effort, and yet they still out-perform their monolingual peers, suggesting that they use their brain more efficiently.”

Knowing a second language made no difference for the young adults in the study, who outperformed both older groups. Gold says the older bilinguals appear to have built up a kind of cognitive reserve from their lifetime of enhanced mental activity. 

Gold's research appears to confirm a previous study on bilingualism among Alzheimer’s patients. That study showed bilinguals developed more atrophy from the brain-wasting disease, but that they were able to function at the same cognitive level as patients with less atrophy. 

"[That] suggested  that their bilingualism is helping them to compensate for that more [advanced] brain atrophy," Gold says. "The finding that we had is consistent with that because it basically says that bilinguals as seniors are able to do more with less.”

Gold says the study confirms bilingualism can play a functional, protective role in the brain. Gold says his next step is to explore whether learning a second language or immigrating to another country as an adult can provide some of the same mental advantages as lifelong bilingualism.