For instance, bilinguals 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 pre-schoolers 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 colour, 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 colour. 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 skilfully from one thing to another, and holding information in mind—like remembering a sequence of directions while driving.

Henceforth, the tussle between two simultaneously active language systems improves these aspects of cognition. Until recently, researchers thought the bilingual advantage stemmed primarily from an ability for inhibition that was enhanced by the exercise of suppressing one language system: this suppression, it was thought, would help train the bilingual mind ignore distractions in other contexts. Nonetheless, 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.

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. 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 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.

In conclusion, bilinguals have stronger cognitive skills than monolinguals, leading to a delay in the onset of dementia and improving the brain's executive function. This directs the processes humans use in planning, problem solving, and other activities. 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.

1. What is the subject/topic of this essay? (1 point)


2. Who is the intended audience/reader for this essay? (1 point)


3. What is the writer’s main purpose? Choose the correct answer from a, b, or c. (1 point)
a. To inform and persuade
b. To compare and contrast
c. To describe a process

4. Write the opening sentence of this essay that hooked the reader. (1 point)


5. Which type of background is provided in the introductory paragraph? Choose the correct answer from a, b, or c. (1 point)
a. General to specific
b. Anecdote
c. Historical