There are probably no cognitive benefits to bilingualism

About one week ago I wrote about bilingual education, and I admitted my mild skepticism about the research about the benefits of bilingualism. A friend emailed me and wondered why I was only “mildly skeptical.” Partly I didn’t want the comments to get sidetracked, but recently friends on Facebook have started to get exercised that Ron Unz is running for the Senate, and how bad he is for not giving the children the opportunity to be bilingual. And of course all the research that confirms how great bilingualism is referenced.

So here’s an article from last month that my friend sent me. I’ll quote the appropriate section, you’ve seen this movie before, The Bitter Fight Over the Benefits of Bilingualism: For decades, some psychologists have claimed that bilinguals have better mental control. Their work is now being called into question:

But a growing number of psychologists say that this mountain of evidence is actually a house of cards, built upon flimsy foundations. According to Kenneth Paap, a psychologist at San Francisco State University and the most prominent of the critics, bilingual advantages in executive function “either do not exist or are restricted to very specific and undetermined circumstances.”

Paap started looking into bilingualism in 2009, having spent 30 years studying the psychology of language. He began by trying to replicate some seminal experiments, including a classic 2004 paper by Bialystok involving the Simon task. In that task, volunteers press two keys in response to colored objects on a screen—for example, right key for red objects, left for green. People react faster if the position of the keys and objects match (red object on right half of the screen) than if they don’t (red object on left). But Bialystok found that twenty Tamil-English bilinguals from India were faster and more accurate at these mismatched trials than twenty English-speaking monolinguals from Canada. They were better at suppressing the location of the objects and focusing on their color—a sign of superior executive function.

“It was a really exciting finding and one that I thought would be easy to study with my students,” says Paap. “But we just couldn’t replicate any of the effects.” After years of struggling, he published his results in 2013: three studies, 280 local college students, four tests of mental control including the Simon task, and no sign of a bilingual advantage.“That broke the dam,” he says. “Others started submitting negative results and getting their articles published.”

Jon Andoni Duñabeitia, a cognitive neuroscientist at the Basque Center on Cognition, Brain, and Language, was one of them. In two large studies, involving 360 and 504 children respectively, he found no evidence that Basque kids, raised on Basque and Spanish at home and at school, had better mental control than monolingual Spanish children. “I am a multilingual researcher working in a multilingual society,” says Duñabeitia. “I’d be very happy to see an advantage for bilinguals! But science is what it is. We find no difference and we have replicated it several times, in older adults, kids, and young adults at university.”

For example, one group of researchers analyzed 104 abstracts on bilingualismthat were presented at scientific conferences. They found that 68 percent of abstracts that found an executive-function advantage were eventually published in journals, compared to just 29 percent that found no advantage. This publication bias, a common problem in psychology and science as a whole, means that the evidence for the phenomenon seems stronger than it actually is.

But Paap doesn’t think much of the published evidence either. He found that a bilingual advantage only shows up in one in six tests of executive function, and mostly in small studies involving 30 or fewer volunteers. The largest studies, involving a hundred or more, all found negative results.

The proponents of bilingualism as a cognitive benefit have reacted angrily. Read the whole thing. But it’s probably not a real strong effect if there is any at all. Just another battle in the replication wars….

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