The Effect of Bilingualism on Cognition: Evidence from Early and Late Bilinguals

Previous research demonstrates that bilinguals have an advatange over monolinguals in several extra-linguistic domains. Using the Simon Task, which putatively measures inhibitory control, Bialystok, Craik, Klein, and Viswanathan (2004) illustrate that early bilinguals are faster and show less of a Simon effect than monolinguals, a disparity that becomes more pronounced in late adulthood. The posited mechanisms responsible for this advantage is enhanced inhibitory control and selective attention, due to life long daily use of two languages. However, there is some contention regarding both which cognitive functions are implicated in the Simon task and whether inhibitory control is the major mechanism underlying bilingual language processing. Previous studies have focused on highly proficient early bilinguals who may mobilize subtly different processes compared to other bilingual groups. The present study attempts to elucidate the mechanisms responsible for this bilingual cognitive advantage by comparing early and late bilinguals on both the Simon task and the Garner task, which measures selective attention, without requiring the inhibition of a response. In addition, results on the Simon task are reinterpreted to uncover an event file effect, a measure of cognitive flexibility (Hommel, 2004). Our question is: Can a second language learned in adulthood bestow the same cognitive advantage as one learned early in life? We predicted that bilinguals would demonstrate less of a Simon effect and of a Garner effect than monolinguals, with differential results for the two bilingual groups. We also expected that bilinguals would show less of an event file effect than monolinguals. We found main effects for age and congruency on the Simon task, an event file effect across all groups which interacted with age, and no Garner interference for any groups. Limitations of the present study are addressed. Further directions to reveal the dynamics of the bilingual mind are suggested.