纽约时报文摘 | 为什么掌握两种语言的人更聪明 Why Bilinguals Are Smarter


Editor’s Note: We’re resurfacing this story from the archives to show you how learning a second language can improve how you think.

SPEAKING two languages rather than just one has obvious practical benefits in an increasingly globalized world. But in recent years, scientists have begun to show that the advantages of bilingualism are even more fundamental than being able to converse with a wider range of people. Being bilingual, it turns out, makes you smarter. It can have a profound effect on your brain, improving cognitive skills not related to language and even shielding against dementia in old age.

This view of bilingualism is remarkably different from the understanding of bilingualism through much of the 20th century. Researchers, educators and policy makers long considered a second language to be an interference, cognitively speaking, that hindered a child’s academic and intellectual development.

They were not wrong about the interference: there is ample evidence that in a bilingual’s brain both language systems are active even when he is using only one language, thus creating situations in which one system obstructs the other. But this interference, researchers are finding out, isn’t so much a handicap as a blessing in disguise. It forces the brain to resolve internal conflict, giving the mind a workout that strengthens its cognitive muscles.

Bilinguals, for instance, seem to be more adept than monolinguals at solving certain kinds of mental puzzles. In a 2004 study by the psychologists Ellen Bialystok and Michelle Martin-Rhee, bilingual and monolingual preschoolers were asked to sort blue circles and red squares presented on a computer screen into two digital bins — one marked with a blue square and the other marked with a red circle.
比如,双语者似乎比单语者更擅长解决某些类型的智力题目。在心理学家埃伦·比亚利斯托克(Ellen Bialystok)和米歇尔·马丁-李(Michelle Martin-Rhee)于2004年进行的一项研究中,双语和单语学龄前儿童被要求将电脑屏幕上蓝色的圆形和红色的正方形分别放进两个数字箱里——一个有蓝色正方形标记,另一个有红色圆形标记。

In the first task, the children had to sort the shapes by color, placing blue circles in the bin marked with the blue square and red squares in the bin marked with the red circle. Both groups did this with comparable ease. Next, the children were asked to sort by shape, which was more challenging because it required placing the images in a bin marked with a conflicting color. The bilinguals were quicker at performing this task.

The collective evidence from a number of such studies suggests that the bilingual experience improves the brain’s so-called executive function — a command system that directs the attention processes that we use for planning, solving problems and performing various other mentally demanding tasks. These processes include ignoring distractions to stay focused, switching attention willfully from one thing to another and holding information in mind — like remembering a sequence of directions while driving.
来自大量这类研究的证据共同表明,双语经历会提升大脑所谓的执行功能(executive function)——一个命令系统,指挥我们用来规划、解决问题和完成其他各种各样对智力有要求的任务的注意力过程。这些过程包括忽略干扰、保持注意力集中、随意转移注意力和在脑海中储存信息——如一边开车一边记住一连串的方向。

Why does the tussle between two simultaneously active language systems improve these aspects of cognition? Until recently, researchers thought the bilingual advantage stemmed primarily from an ability for inhibition that was honed by the exercise of suppressing one language system: this suppression, it was thought, would help train the bilingual mind to ignore distractions in other contexts. But that explanation increasingly appears to be inadequate, since studies have shown that bilinguals perform better than monolinguals even at tasks that do not require inhibition, like threading a line through an ascending series of numbers scattered randomly on a page.

The key difference between bilinguals and monolinguals may be more basic: a heightened ability to monitor the environment. “Bilinguals have to switch languages quite often — you may talk to your father in one language and to your mother in another language,” says Albert Costa, a researcher at the University of Pompeu Fabra in Spain. “It requires keeping track of changes around you in the same way that we monitor our surroundings when driving.” In a study comparing German-Italian bilinguals with Italian monolinguals on monitoring tasks, Mr. Costa and his colleagues found that the bilingual subjects not only performed better, but they also did so with less activity in parts of the brain involved in monitoring, indicating that they were more efficient at it.
双语者与单语者之间的关键差别或许更为基本:观察环境的能力更强。“双语者不得不非常频繁地转换语言——可能用一种语言和父亲对话,用另一种语言和母亲交流,”西班牙庞培法布拉大学(Pompeu Fabra University)的研究人员阿尔贝特·科斯塔(Albert Costa)说。“它要求像我们在开车时观察周围环境一样追踪四周的变化。”在一项对比德语-意大利语双语者和意大利语单语者在观察任务中的表现的研究中,科斯塔和同事发现,双语实验对象不仅表现得更好,而且观察时使用的大脑相关区域的活跃程度较低,这表明他们的观察效率更高。

The bilingual experience appears to influence the brain from infancy to old age (and there is reason to believe that it may also apply to those who learn a second language later in life).

In a 2009 study led by Agnes Kovacs of the International School for Advanced Studies in Trieste, Italy, 7-month-old babies exposed to two languages from birth were compared with peers raised with one language. In an initial set of trials, the infants were presented with an audio cue and then shown a puppet on one side of a screen. Both infant groups learned to look at that side of the screen in anticipation of the puppet. But in a later set of trials, when the puppet began appearing on the opposite side of the screen, the babies exposed to a bilingual environment quickly learned to switch their anticipatory gaze in the new direction while the other babies did not.
在2009年的一项研究中,意大利的里雅斯特国际高级研究学院(International School for Advanced Studies)的阿涅斯·科瓦奇(Agnes Kovacs)对比了从出生就接触两种语言的七个月大的婴儿,和在一种语言环境下长大的同龄婴儿的表现。在最初的一组试验中,婴儿先听到了一段音频提示,接着在屏幕的一侧发现了一个木偶。两组婴儿都学会了在想看木偶时,看向屏幕的那一侧。但在后来的一组试验中,当木偶开始出现在屏幕上相反的一侧时,接触双语环境的宝宝很快便学会了将期望的眼神转向新的方向,而其他宝宝却没有。

Bilingualism’s effects also extend into the twilight years. In a recent study of 44 elderly Spanish-English bilinguals, scientists led by the neuropsychologist Tamar Gollan of the University of California, San Diego, found that individuals with a higher degree of bilingualism — measured through a comparative evaluation of proficiency in each language — were more resistant than others to the onset of dementia and other symptoms of Alzheimer’s disease: the higher the degree of bilingualism, the later the age of onset.
双语能力的影响还会延续到暮年。在最近对44名老年西班牙语-英语双语者进行的一项研究中,以加州大学圣迭戈分校(University of California, San Diego)神经心理学家塔马·高兰(Tamar Gollan)为首的科学家发现,双语程度更高——通过每种语言的相对熟练水平来衡量——的人比其他人更能防止失智和其他阿尔茨海默氏症的症状出现:双语程度越高,出现的时间越晚。

Nobody ever doubted the power of language. But who would have imagined that the words we hear and the sentences we speak might be leaving such a deep imprint?

余和吉特·巴塔查尔吉(Yudhijit Bhattacharjee)是《科学》杂志特约撰稿人。