John Secor, professor of French at Morehead State University in Morehead, Kentucky, has been speaking two languages since he was a small boy in Canada.
He’s also a musician and singer and when he’s playing with a group, he finds he’s better able to hear multiple voices and switch beats and parts than some of his monolingual band mates.
“I have noticed this [advantage] in myself compared to others,” said the 57-year-old Secor.
New research published Tuesday in The Journal of Neuroscience helps explain why Secor’s mental reactions are so sharp, even in middle age –- the brains of people who are bilingual work more efficiently than people who speak only one language.
Neuroscientists have been accumulating strong evidence that knowing, and constantly using, a second language starting in childhood can significantly delay a decline in brain power. University of Kentucky in Lexington researchers wanted to know why some people’s brains seem protected.
The benefit appears to accrue chiefly in the process of cognitive control. As we pass through middle age, our brains become slower at switching from one task to another and at shutting out unwanted distractions. So our executive functions, such as the ability to concentrate on a task without other thoughts intruding, show a noticeable fall off.
“There was already some behavioral evidence looking at reaction and accuracy showing that bilinguals slow less as they age in these cognitive areas,” neurobiologist Brian Gold, Ph.D told NBCNews. “We wanted to understand what the neural basis of that is.” In other words, what parts of the brain are involved in this protective effect, and how does it work?
First, Gold had to find older people who’d been bilingual since age 10, and a set of other test subjects matched for education and socioeconomic status who speak just one language. Finding enough bilingual people in central Kentucky proved difficult, but eventually, the researchers had their participants, including Secor.
Gold then asked 15 monolingual people and 15 bilinguals with a median age of 63 to decide if a shape was a circle or a square, making their choice by pressing a button. Then they had to decide if a shape was red or blue. Finally, they had to rapidly switch between these two tasks. Bilingual people showed faster reaction times during the task switching phase than did monolingual people.
Using new volunteers, this time including 20 younger bilingual and 20 monolingual people as well as two groups of 20 bi- and monolingual oldsters, Gold had them perform the same tasks while imaging their brains.
Previous studies have shown that younger people are faster at switching and require less brain power. They’re more efficient. Gold got the same results: Both groups of young people had faster reaction times than both groups of older people during the task switching phase. But bilingual older adults displayed significantly faster reaction times than their peers -- closer to the youngsters.
When the imaging data was analyzed, the scientists found that during the switch phase of the tests, everyone was using parts of the prefrontal cortex and anterior cingulate, executive parts of the brain where we reason and weigh options. The imaging data showed that older people who spoke just one language required more brain effort in these areas than did either set of younger people, or their older bilingual peers.
The brain shrinks with aging, but brain volume was not significantly different between the two groups of older adults. So the advantage of bilingual speakers doesn’t appear to be structural. Rather, the researchers speculate, “it may be the case that the bilingual requirement to switch between languages on a daily basis serves to tune the efficiency of language-switching regions…and that over time the increased efficiency of these regions comes to benefit even nonlinguistic, perceptual switching,” perhaps showing up in Secor’s music abilities, for example.
Gold, who also grew up in Canada as a bilingual youngster and who has made a specialty of studying the aging brain, said that the jury is still out on whether bilingualism can prevent or delay the onset of dementia, but he thinks it looks promising.
As to whether it’s too late for those of us struggling to learn a new language as adults to get any of this cognitive benefit, he said: “It’s not exactly known. There’s not a lot of literature on that but what there is suggests two things: You need to acquire it when you are young and you need to do it every day. It’s not enough to dabble in a second language…You need a much more regular workout, constantly switching between languages.”
So while those Mandarin classes for toddlers may seem obnoxiously precious, and your 6-year-old may say he hates you for making him learn French, you will get a big "xie xie" or “merci beaucoup” when they grow up.
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