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 biling ualism 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 intellectualdevelopment.

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 EIlen 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.

In the first task, the children had to sort the shapes by color, placing blue circles in the in 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一 -acommand 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 informationin mind一-like remembering a sequence of directions while driving.

Why does the tussle between two simultaneously active language systems improve these aspects 0f 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 |ine 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一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-ltalian bilinguals with Italian monolinguals on monitoring tasks, Mr. Costa and his collagues 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.

How is language interference perceived by modern researchers according to the passage?

Today´s adults grew up in schools designed to sort us into the various segments of our social and eco-nomic system. The amount of time available to learn was fixed : one year per grade. The amount learned by the end of that time was free to vary:some of us learned a great deal;some,very little. As we advanced through the grades,those who had learned a great deal in previous grades continued to build on those foundations.

Those who had failed to master the early prerequisites within the allotted time failed to learn that which fol-lowed. After 12 or 13 years of cumulative treatment of this kind ,we were ,in effect, spread along an achieve-ment continuum that was ultimately reflected in each student´s rank in class upon graduation.

From the very earliest grades, some students learned a great deal very quickly and consistently scored high on assessments. The emotional effect of this was to help them to see themselves as capable learners, and so these students became increasingly confident in school. That confidence gave them the inner emotional strength to take the risk of striving for more success because they believed that success was within their reach. Driven forward by this optimism,these students continued to try hard, and that effort continued to re-sult in success for them. They became the academic and emotional winners. Notice that the trigger for their e-motional strength and their learning success was their perception of their success on formal and informal as-sessments.

But there were other students who didn´t fare so well. They scored very low on tests, beginning in theearliest grades. The emotional effect was to cause them to question their own capabilities as learners. They be-gan to lose confidence, which, in turn, deprived them of the emotional reserves needed to continue to take risks. As their motivation warned, of course, their performance plummeted. These students embarked on what they believed to be an irreversible slide toward inevitable failure and lost hope. Once again, the emotional trigger for their decision not to try was their perception of their performance on assessments.

Consider the reality--indeed, the paradox--of the schools in which we were reared. If some students worked hard and learned a lot, that was a positive result, and they would finish high in the rank order. But if some students gave up in hopeless failure, that was an acceptable result, too, because they would occupy places very low in the rank order. Their achievement results fed into the implicit mission of schools : the grea-ter the spread of achievement among students, the more it reinforced the rank order. This is why, if some students gave up and stopped trying(even dropped out of school), that was regarded as the student´s prob-lem, not the teacher´s or the school´s.

Once again, please notice who is using test results to decide whether to strive for excellence or give up in hopelessness. The "data-based decision makers" in this process are students themselves. Students are deci-ding whether success is within or beyond reach, whether the learning is worth the required effort, and so whether to try or not. The critical emotions underpinning the decision making process include anxiety, fear of failure, uncertainty, and unwillingness to take risks--all triggered by students´ perceptions of their own capa-bilities as reflected in assessment results.

Some students responded to the demands of such environments by working hard and learning a great deal. Others controlled their anxiety by giving up and not caring. The result for them is exactly the opposite of the one society wants. Instead of leaving no child behind, these practices, in effect, drove down the achieve-ment of at least as many students as they successfully elevated. And the evidence suggests that the downside victims are more frequently members of particular socioeconomic and ethnic minorities.

Which of the following is closest in meaning to the underlined word" plummeted" in Paragraph 3 ?