Do Bilinguals have an Advantage Over Monolinguals When It Comes to Executive Functions?

Do Bilinguals have an Advantage Over Monolinguals When It Comes to Executive Functions?

The prefrontal cortex regulates processes necessary to support goal directed behaviors. These processes, known as executive functions (EF), include shifting ability, inhibitory control, and updating. Moreover, the prefrontal cortex is believed to be essential for language control in people who speak more than one language. That is, leading theorists propose non-target language is inhibited when a bilingual speaks. In support, prior research from our laboratory has shown differences favoring bilinguals over monolinguals in neural inhibitory control. In this study, we speculated that bilinguals would not only outperform monolinguals on tests of inhibition, but that a bilingual advantage would also extend to the other two components of EF (i.e., shifting and updating).

Monolinguals (N=69) and bilinguals (N=46) were matched on a test of nonverbal intelligence, socio- economic status, and parental education. Results revealed that indeed bilinguals outperformed monolinguals on a test (WCST) assessing shifting abilities. Specifically, compared to monolinguals, bilinguals achieved a higher number of categories and made fewer errors. On a test assessing updating (N-back), while monolinguals showed faster reaction times, bilinguals were more accurate. Lastly, contrary to our prediction, bilinguals did not outperform monolinguals on a test (Stroop) assessing inhibition. Overall, our findings support and extend a growing body of research showing that speaking two languages has advantages that go beyond linguistic abilities.