Task Switching Abilities in Bilinguals: The Importance of Language Dominance and Acculturation

Abstract

Objective: The current study examined group differences between monolingual English and bilingual English/Spanish speakers in task switching. Additionally, relationships between English language dominance and time since immigration were explored within bilingual immigrants. Method: In this cross-sectional, correlational study, task switching was measured via a computerized paradigm in a large community sample of adults. In the bilingual sample, degree of English language dominance (measured as a ratio of English to Spanish phonemic verbal fluency scores) was hypothesized to correlate with switch cost. Exploratory analyses were conducted to examine relationship between immigration history, English language dominance, and switching cost within a subsample of bilingual immigrants. Results: There were no group differences between monolingual and bilingual participants in switch cost. Among all bilinguals, greater English dominance predicted less switch cost (b = −.20, p = 0.01). Among non-U.S. born bilinguals, greater time since immigrating to the U.S. and greater English dominance predicted less switch cost (i.e., more efficient switching; (b = −0.37, p = 0.025). Conclusions: These findings suggest that the effects of bilingualism on executive control, specifically task switching, may be impacted by factors related to acculturation rather than bilingualism alone, which may partially explain the variability seen in prior studies.