ผมนำ 3 บทความจากนิตยสาร Time ข้างล่างนี้มาให้ท่านลองอ่านดู ใจความสำคัญก็คือ คนที่พูด 2 ภาษาจะมีอาการของโรคขี้หลงขี้ลืม (Alzheimer’s)ช้ากว่าคนพูดภาษาเดียว 4-5 ปี และแม้บางคนจะมาเรียนภาษาที่สองตอนวัยกลางคนหรือเมื่อแก่แล้ว การเรียนภาษาที่สองก็ช่วยให้สมองกระฉับกระเฉงขึ้น ท่านลองเข้าไปอ่านรายละเอียดดูเอาเองแล้วกันครับ
Why Speaking More than One Language May Delay Alzheimer’s
There are many ways in which speaking another language may contribute to a well-lived life. You can talk to a whole lot more of Earth’s inhabitants, for one thing. You can also enjoy books, music and films in their original language, and throw a few more “skills” onto your résumé. Now add to that list the findings of new studies suggesting that speaking multiple languages may also help protect cognitive health over the long term.
In a study of 450 Alzheimer’s patients, led by Ellen Bialystok, a psychology professor at York University in Toronto, those who were bilingual for most of their lives were able to stave off symptoms of Alzheimer’s for four to five years longer than people who spoke only one language. Although the ability to speak two languages didn’t prevent the memory-robbing disease, it did delay its symptoms from appearing.
(More on Time.com: At Last, Some Hope for Preventing the Slow Mental Decline of Alzheimer’s)
Why? The key may be something called cognitive reserve. Learning and speaking two languages requires the brain to work harder, which helps keep it nimble. It’s the same use-it-or-lose-it reasoning that underlies advice to do crossword puzzles and to continue to learn new skills throughout life — the idea is to help the brain create and maintain more neural connections. Brains with more cognitive reserve — and therefore more flexibility and executive control — are thought to be better able to compensate for the loss of neurons associated with Alzheimer’s.
(More on Time.com: A Blood Test To Predict Alzheimer’s)
Another recent study backed up the connection between bilingualism and executive control. The study, which involved babies who were exposed to two languages from birth, found that bilingual infants don’t confuse their two languages because they learn very early to pay attention better, according to the AP:
[University of British Columbia psychologist Janet] Werker tested babies in Spain who were growing up learning both Spanish and Catalan. She showed the babies videos of women speaking languages they’d never heard — English and French — but with the sound off. By measuring the tots’ attention span, Werker concluded that babies could distinguish between English and French simply by watching the speakers’ facial cues. It could have been the different lip shapes.
“It looks like French people are always kissing,” she joked, while the English “th” sound evokes a distinctive lip-in-teeth shape. Whatever the cues, monolingual babies couldn’t tell the difference, Werker said.
Lest bilingual folks start feeling too high and mighty, another new study involving 230 people found that the benefits to memory in elderly adults increased with the number of languages they spoke: those who spoke four or more languages were five times less likely to develop cognitive problems, compared with mere bilinguals. People who spoke three languages were three times less likely to have cognitive problems than people who spoke two. The study will be presented at the American Academy of Neurology’s annual meeting in Honolulu in April.
(More on Time.com: Have Trouble Paying Bills? Could Be a Sign of Alzheimer’s)
What about those of us who weren’t lucky enough to learn two languages in infancy? Experts say there’s plenty of reason to be optimistic. Some of the cognitive benefits of learning another language still apply even when the language is learned in mid-life or later — and even if you never achieve fluency. The idea is just to keep your brain active.
Fresh from a country with two official languages: a new Canadian study suggests that being bilingual will, on average, postpone the onset of dementia by 4.1 years. Even after adjusting for schooling and immigration status, the results were unequivocal: being a polyglot (or at least a biglot) fights brain rot. What's not clear is why. Researchers speculate the ability to operate in two languages could — like exercise or stimulating leisure and social activity — help the brain continue normal functions even as it decays physically. Just don't expect great things from your French refresher course. The study, appearing in the February issue of Neuropsychologia, defines bilingual as "regularly using at least two languages" throughout adulthood — and there's no evidence that flipping through phrase books will help.
Want to Prevent Aging? Learn a New Language
The current economic doldrums have many Americans casting a worried eye on their retirement accounts. But in order to assure yourself of a comfortable old age, there’s another fund on which you should be keeping tabs — a mental one. Ask yourself: How big is my cognitive reserve?
Cognitive reserve is the term scientists use to describe the extent of the brain’s capacity to resist aging and degenerative conditions like Alzheimer’s disease. The notion that such a capacity could exist originated in a surprising discovery made almost 25 years ago, when the brains of 137 elderly residents of a nursing home were dissected after their deaths. Remarkably, researchers failed to find a direct relationship between the degree of Alzheimer’s disease detected in the residents’ brains (revealed by the presence of structures called plaques) and how impaired they had been while they were alive. In other words, some of these individuals were able to resist the ravages of the illness better than others — but how?
The neuroscientists from the University of California, San Diego, reported that the subjects whose abilities were less affected by Alzheimer’s were those with bigger brains and a greater number of neurons — suggestive evidence that keeping their brains active had built a bulwark against decline.
Since then, the idea that a deep cognitive reserve provides protection has received support from many different quarters. Research on bilingualism by Ellen Bialystok of York University in Toronto, for example, has demonstrated that speaking more than one language delayed the onset of Alzheimer’s symptoms by an average of five years. In a study published last year in the journal Cortex, Bialystok and her co-authors used brain scans to measure the extent of brain atrophy in monolingual and bilingual individuals who showed early signs of Alzheimer’s disease. The amount of atrophy in the bilinguals’ brains was much greater — indicating that even though their physical disease was more advanced than the monolinguals’, they’d been able to keep functioning at the same level. Bialystok theorizes that the lifelong mental exercise required to speak multiple tongues — remembering which word belongs to which language — helps bilinguals augment their cognitive reserves.
Now a new study suggests that mental activity can offset the effects not just of degenerative diseases, but of normal aging as well. In an article published this month in the journal Neurobiology of Aging, Nina Kraus and her colleagues at Northwestern University measured the ability of subjects to respond quickly and accurately to sounds that they heard. Some of the study’s participants were young adults aged 32 and under, while others were between 46 and 65 years of age; some were experienced musicians, and some were not. Kraus found that the middle-aged musicians, who’d spent decades honing their craft, outperformed not only their nonmusician peers but also the nonmusicians many years their junior. The mental rigor required by the practice of music effectively acted as an antidote to aging, keeping their nervous systems youthful.
We’ve all been taught the importance of beginning early in saving money for retirement. Accumulating mental capital — by learning to play an instrument, speak in a foreign language or master any complex skill — works the same way. If you want a generous cognitive reserve to see you through your golden years, you’d better start contributing now.