Cognitive enhancement is just the start. According to some studies, my memories, my values, even my personality may change depending on which language I happen to be speaking. It is almost as though the bilingual brain houses two separate minds. All of which highlights the fundamental role of language in human thought. “Bilingualism is quite an extraordinary microscope into the human brain,” says cognitive neuroscientist Laura Ann Petitto of Gallaudet University.
The image of bilingualism has not always been this rosy. For many parents, the decision to raise children speaking two languages was controversial. Since at least the 19th century, educators warned that it would confuse the child, making him unable to learn either language properly. At best, they thought, the child would become a jack-of-all-trades and master of none. At worst, they suspected it might hinder other aspects of development, resulting in a lower IQ.
These days, such fears seem unjustified. True, bilingual people tend to have slightly smaller vocabularies in each language than their monolingual peers, and they are sometimes slower to reach for the right word when naming objects. But a key study in the 1962 by Elizabeth Peal and Wallace Lambert at McGill University in Montreal found that the ability to speak two languages does not stunt overall development. On the contrary, when controlling for other factors that might also affect performance, such as socioeconomic status and education, they found that bilinguals outperformed monolinguals in 15 verbal and nonverbal tests.
Although a trickle of research into the benefits of bilingualism followed that study, it is only within the past few years that bilingualism has received a lot of attention.
In part, the renewed interest comes from recent technological developments in neuroscience, such as functional near-infrared spectroscopy (fNIRS), a form of brain imaging that can peer inside the brains of babies as they sit on their parents’ laps. For the first time, researchers can watch young brains in their initial encounters with language.
Using this technique, Petitto and her colleagues discovered a profound difference between babies brought up speaking one language and those who spoke two. According to popular theory, babies are born “citizens of the world,” capable of discriminating the sounds of any language. By the time they are a year old, however, they seemed to have lost this ability, homing in exclusively on the sounds of their mother tongue. That seemed to be the case with monolinguals. But Petitto’s study found that bilingual children showed increased neural activity in response to completely unfamiliar languages even at the end of their first year.