The influence of bilingualism on adolescent cognition: The roles of biculturalism, the bilingual profile, and linguistic similarity

A broad and comprehensive approach was taken in the present study, to examine how acculturation, the bilingual profile (linguistic, affective, educational, and cultural), as well as linguistic similarity modulate any effects on executive functions (ΕFs) in adolescence. We also further explored whether any such effects are developmental in nature, and thus, modulated by adolescents’ age. The study was pre-registered and investigated four bilingual adolescent populations (N = 191), and two groups of monolingual adolescents (N = 100) from the Balkan region. Participants were tested on a range of cognitive outcomes, and rich contextual information was collected. We were able to move beyond studying factors in isolation by using data-driven cluster analyses to derive groups of more or less balanced profile bilinguals. While we found significant age-driven improvements in adolescents’ performance, we found no consistent evidence for an effect of bilingualism on EFs, across a range of tasks, taking into consideration a range of potential confounds and as a function of acculturation, bilingual profile or linguistic similarity. This suggests that when considering the wider bilingual picture, there is no evidence for a bilingual advantage in a range of EFs, even at such a sensitive period for cognitive development.