05英语编者按：如何保持思维年轻有活力，最近研究表明学习一门外语也许能帮你做到！不管你多少岁，从现在开始学习吧！
Parli Italiano? ¿Hablas Español? Can you speak more than one language? No matter how old you are, it’s not too late to learn. In fact, new research finally shows that learning a second (or third) language as an adult can help slow brain decline.
The benefits of bilingualism are no secret. Previous studies suggest people who regularly speak more than one language show a later onset of dementia and improved mental function. But there was always the pesky problem of correlation vs. causation: Were smarter people simply more likely to learn extra languages? Or were they smarter because they learned extra languages? A recent study from the University of Edinburgh is the strongest evidence yet that, indeed, learning a second language can improve your mental functions—even if you learn the language later in life.
The results come thanks to something called the Lothian Birth Cohort study. In 1947, 1100 11-year-old school children around Edinburgh, Scotland, were given cognitive tests. All of them spoke just one language at the time, but many went on to learn at least one other language as adults, making them (and their test scores) a gold mine for language researchers like Thomas Bak. And because “people of this generation don’t move around that much, it was possible trace them as well,” Bak tells mental_floss.
He and his team tracked down 853 of the original test subjects, now in their early 70s. One-third had learned to speak an additional language since the original test, and 65 of those became bilingual after turning 18. Some learned Gaelic, others learned French in school, or German. Others even traveled to Africa and learned African languages.
Bak gave the same cognitive tests to the original participants to compare their performance with that of their 11-year-old selves. The original scores set a baseline for measuring and predicting mental function: If they performed poorly at age 11, researchers predicted the subjects would also perform relatively poorly at age 73. If their original test scores were high, they would probably be high again at age 73. The results show that “people perform better than you would predict only on the basis of if they learn another language,” says Bak.
This is an important finding, Bak says, because for a long time it was believed that the only time to learn a second language was as a child, when your brain is still nice and sponge-y. This research says even learning it later has positive effects on mental function.
But what is it about language that is so good for our brains? Bak says the act of switching between several languages may give the brain a workout, since you have many more words and meanings to choose from before speaking. He compares it to the physical workout of swimming. “You are using most of your muscles and breathing and so on,” he says. “In being bilingual you’re activating a whole range of different mental functions.”
If you learn three, four, or even five languages, does your brain become stronger with each? Bak says this isn’t clear yet. In theory, the more languages you know, the more mental switches you’ll need to make when speaking, he says, but it’s hard to generalize about something as complicated as language. But there’s no harm in learning as many as possible.
And if you think you’re too old, just remember: our brains are designed for this. “Bilingualism might have been the original state of human communities,” Bak says. “It was more the rule than the exception. The fact we have this ability means in a way our brains are designed to do it.”
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