The gospel of the day is that raising children to speak and understand more than one language is good for their cognitive development. A number of studies released in the past few years have indicated that multilingual speakers may even have more focused brains and higher processing abilities. Not surprisingly, this research — and the media attention that has accompanied it — has led to renewed efforts among more-affluent parents to secure spots for their children in language immersion schools and employ multilingual nannies who can expose their wee ones to another language from the earliest ages.
A skeptic might ask, however, if it's possible that the cognitive benefits such bilingual children receive are more a result of their privileged socioeconomic status — and the resources they have access to — rather than simply an ability to converse in Spanish or Mandarin.
The encouraging answer is: not really.
Studies show that the brain does indeed gain cognitive benefits from being bilingual, regardless of one's socioeconomic status. And that has potentially significant implications in the United States, where native bilinguals tend to be poorer than the general population.
It helps to understand what, exactly, you gain from speaking more than one language. The benefit is quite specific to a very important aspect of our brain's functioning, says Ellen Bialystok, a cognitive neuroscientist at York University in Toronto who has been examining bilingualism's effects on the mind for decades.
Being bilingual improves the executive functioning processes that manage things such as attention, working memory, planning, and problem-solving. The bilingual mind experiences a workout from constantly suppressing one language while activating another, which builds up the brain's cognitive processes.
"This is the most important cognitive system we have," Bialystok says. "There are studies showing that executive function in childhood predicts academic outcomes in a narrow sense, and broader success outcomes in life."
But when Bialystok started doing research on the bilingual effect, there was a concern that socioeconomic factors were interfering with the results. Now there are a number of studies that, when taken together, she says "rule out that our effects are limited to a certain socioeconomic status, or even worse, confounded by socioeconomic status and not reflecting the effects of bilingualism."
One study Bialystok was involved with looked at a group of low-income children from a specific region of Portugal. On a litany of tests, measuring things like intelligence and visual memory, the kids who stayed in Portugal and those who had immigrated to Luxembourg and learned to speak Luxembourgish performed the same. But on the measures that test the brain's control function, researchers found that the kids in Luxembourg "significantly outperformed those who stayed behind," Bialystok says.
Overall, kids from poorer socioeconomic backgrounds tend to perform worse than wealthier kids on executive functioning measures. Bilingualism, it appears, can help compensate for that gap.
A separate 2008 study from University of Washington researchers compared Spanish-English native bilingual kindergarteners (who tended to come from more disadvantaged backgrounds) to English speakers enrolled in second-language immersion and English-only speakers. The native bilinguals outperformed the other groups on executive function tests. But that was only after controlling for factors like socioeconomic status; before doing that, their scores were the same. Given the impact of socioeconomic and other factors on cognitive development, those kids should have done worse than their more-advantaged peers. Essentially, disadvantaged bilinguals may be "doing more with less," the researchers noted.
That study was particularly notable because after English, Spanish is by far the most common spoken language in the U.S. About 60 million people, or one in five, speak a language other than English at home, according to 2011 Census data. And 21 percent of them live below the poverty line, compared to just 14 percent of the general population.
Myths still persist around bilingualism. For a long time, educational experts concluded that it took bilingual kids much longer to develop language skills, says Sarah Roseberry Lytle, the director of translation at the University of Washington's Institute for Learning and Brain Sciences. It turns out that's not the case; it just looked that way when those kids were assessed in only one language.
Support for bilingual or multilingual education continues to grow, even where it was once viewed with suspicion. California, for instance, is now home to an explosion of dual-language immersion programs, where 5-year-olds learn in Italian and Japanese. But as recently as 1998, California voters banned bilingual-education programs, mandating that students whose first language was not English be taught "overwhelmingly in English." Since then, the gap in test scores between those students and native English speakers has widened.
Encouraging bilingualism could help toward closing that gap. While "there is no benefit of bilingualism with general IQ and things like that," says Lytle, "if you think about the structure of a classroom day, kids are often asked to switch tasks pretty quickly without retention time. The idea is that bilingual kids are going to be better at task-switching."
But being bilingual doesn't exist in a vacuum for many children, particularly those who come from poorer socioeconomic situations. And having to deal with societal factors that discourage or don't value bilingualism can harm them, says Afra Hersi, a literacy education professor at Loyola University Maryland who has researched bilingual teenagers and their school experiences. "Bilingualism as a distinct advantage is not valued as much in the United States if you are a child from a low socioeconomic circumstance," she says.
There are complicating factors within immigrant communities, as well. Immigrant kids tend to pick up English quicker than their parents, "which puts strains on the family cohesion," says Hersi. "It puts parents and children at odds with each other."
Overall, though, there is a benefit to being bilingual from which everyone, regardless of socioeconomic status, stands to gain — particularly if speaking two languages is seen as a good thing. The bilingual benefit doesn't guarantee greater academic achievement, admission to college, or a high-paying job — but it certainly sets the foundation for greater successes in life.