Speaking two languages fluently helps improve attention, according to new Northwestern research findings. The research, which was published April 30 in the journal Proceedings of the National Academy of Sciences, studied 25 monolingual and 23 bilingual incoming high school freshmen.
Viorica Marian, NU department chair of communication sciences and disorders and the study’s author, said researchers believe that in bilingual people’s brains, both languages are constantly active.
When bilingual people speak or listen, they have to learn to subconsciously block out the other language processing center. In everyday life, this translates to better attention.
Researchers first measured the subjects’ proficiency to confirm their language fluency. All monolinguals spoke only English and all bilinguals spoke only English and Spanish.
Researchers connected the subjects’ brains to electrodes that measured the sound waves generated in the brain stem, a part of the brain that connects to the spinal cord. Subjects listened to a simple sound, the syllable “Da” repeated several times. For this part, both groups’ brain waves looked similar, Marian said. However, when researchers added background noise in addition to the sounds, they found that bilinguals were better able to block out the extra noise.
“When a background noise was incorporated, like in a noisy restaurant, bilinguals showed an advantage over monolinguals, suggesting that bilingualism helps individuals process sounds better,” Marian said.
Marian said that recently, other researchers have shown similar effects in other sections of the brain, but she said the brain stem is different. Because it is a primitive structure in the brain, this research also indicates that these abilities may be one of the brain’s natural and basic functions.
In addition to the sound tests, researchers also gave participants cognitive tests of attention. Marian said the participants whose brains were the best at blocking excess noise also showed the best attention.
“So it seems to be this highly interrelated system,” Marian said. “The biological system influences function and the function influences the biology.”
She added that new research has shown that with each language someone learns, it becomes easier to learn a further language.
Marian, who grew up speaking Romanian and Russian and later learned English, said her future research will focus on people who have become bilingual later in life, such as during high school or college. She said she hopes that demographic changes in the United States will make bilingualism more common.
