The idea that learning to speak two languages is good for your brain has come to be widely accept as fact, particularly in popular media. Studies have shown that bilingual speakers of all ages outperform monolinguals on certain cognitive performance measures. Other studies show delays in the onset of dementia and some even claim enhanced intelligence.
But a handful of attempts to replicate some of these seminal findings have failed to confirm this “bilingual advantage.” The number of studies that have not found a tie between bilingualism and better cognition has risen dramatically over the past few years.A heated debate over this issue now rages in the research community and has gained prominent attention recently with a series of articles in the journal Cortex. A paper by Kenneth Paap of San Francisco State University and colleagues kicked off the fireworks in August, arguing that the evidence now suggests either no bilingual advantage exists, or it only occurs under certain as yet undetermined circumstances. Twenty-one commentaries and a summary by Paap and colleagues followed in October.
The authors were reacting to the intense optimism about the benefits of bilingualism generated by a large number of studies published over the last decade or so. Ellen Bialystok, a psychologist at York University, Toronto, and her colleagues, produced much of the important early work that helped to dismiss the outdated idea that bilingualism could be detrimental to children’s intellectual development. Later studies went further, finding that bilingual children actually perform better than monolinguals in tests of “executive functions” –processes that control thought and behavior and enable complex cognitive tasks like problem solving .