FOR years, researchers in bilingualism have been touting striking findings about how bilingualism affects the brain. Two of the most memorable involve _executive control_ and delayed dementia. With the first, bilinguals have shown that they are better able to focus on demanding mental tasks despite distractions. In other studies, it has been estimated that bilinguals see the onset of dementia, on average, about five years later than monolinguals do.
This week comes new evidence* for the pile: researchers led by Roberto Filippi of Anglia Ruskin University have found that young bilingual pupils did a better job answering tricky questions with a noisy voice in the background than a monolingual control group did. The study was small (just 40 pupils, only 20 in each group). But its robustness is helped by the diversity of the bilinguals, who spoke Italian, Spanish, Bengali, Polish, Russian and others in addition to English. The experimenters tried to distract the pupils with random unrelated recordings in English (which all the pupils spoke) and Greek (which none of them did). The bilinguals did significantly better at ignoring the Greek distraction. (They did just a bit better with the English one.)
The researchers in this line of inquiry tend to share a common hypothesis: that being bilingual is a kind of constant inhibitory mental exercise. With two languages in the mind, nearly everything has two labels (words) and nearly everything can be expressed in two different kinds of sentences (grammar). Every time a thing is named, an alternative must be suppressed. Every time a sentence is constructed, the other way of constructing it must be suppressed. Blocking out distracting information is exactly what researchers find that bilinguals do well. And as for dementia, the effect seems to be a kind of analogue to physical activity over the course of a lifetime keeping a body fit. Mental exercise keeps the brain fit, and bilingualism is just that kind of exercise. (Crucially, the most striking findings relate to native bilinguals. The effects are weak to nonexistent for those who merely have a passable ability, infrequently used, in a second language.)
Why bilinguals seem to do better in quite a few differently designed studies does, however, need more research. Another paper published earlier this year** failed to replicate a cornerstone 2004*** study of the bilingual-advantage research. The new study, using elderly participants, found that Asian-language-plus-English bilinguals in Scotland, as well as Gaelic-English bilinguals, did no better than monolinguals on a task that required ignoring a visual distraction. The authors of the 2014 study speculate that the 2004 study used a crucially different kind of bilingual. Those studied in 2014 in Scotland were not frequently required to switch between their languages. The Gaelic-English bilinguals had not been educated in Gaelic, and presumably spoke it to a small group of friends and family, and only in certain settings. The Asian-language speakers had been educated earlier in their Asian tongues, but in Scotland spoke their heritage language only at home, and used English more outside home and family circles. The researchers in the 2004 study tested pupils educated in both languages, those more likely to have two ready labels for a wide range of vocabulary, and who were forced to switch often.
If the advantage accrues to those who switch more often_and especially those who use more than one language with the same people (like Puerto Rican New Yorkers who rapidly switch back and forth between Spanish and English in the same two-person conversation)_then we are left with a refined version of the _fitness_ analogy. Just as recent exercise trends stress variety over repetition, moving between languages, not just knowledge of two of them, may be a key part of the bilingual advantage. Amazingly, some parents still think bilingualism might harm a child's development. Perhaps selling bilingualism as an elite, varied exercise_a kind of Crossfit of the mind_might convince more parents to give it a try.