Better early or late? Examining the influence of age of exposure and language proficiency on executive function in early and late bilinguals

Previous research has shown that early and late bilinguals differ in their language learning experiences and linguistic outcomes. However, evidence of differences between these bilinguals on measures of executive function (EF) has been mixed. As a result, the current study sought to (1) determine whether early and late bilinguals vary from one another and (2) exhibit cognitive advantages in EF relative to monolinguals. One hundred and five participants (42 monolinguals, 40 early bilinguals and 23 late bilinguals) completed the study. Participants' EF skills were assessed using the Auditorily Cued Number Numeral Task. Overall, the results did not reveal clear advantages for the early bilinguals compared to the two other groups. In fact, early bilinguals and monolinguals were equivalent in their performance on the EF task, whereas the late bilinguals were less accurate, relative to the other two groups. The differences in the performance of early and late bilinguals are discussed in terms of the competition model of second-language learning proposed in previous research. Taken together, these findings indicate that individual differences in EF influence the observed differences found in EF across language groups.