Previous studies of bilingual adults have suggested that bilinguals’ experience with code-switching (CS) contributes to superior executive function (EF) abilities. We tested a highly bilingual developing population in Singapore, a multilingual country where CS occurs pervasively. We obtained CS and EF measures from 43 English–Chinese 8-year-old children (27 females, M = 100 months). We measured spontaneous CS with a novel task and EF in terms of task-switching (Semantic Fluency) and inhibitory control (Stroop task in both languages). Contrary to previous work, CS performance did not significantly predict EF performance in either case. Rather, bilingual language proficiency, i.e., degree of bilingualism (as measured by direct proficiency tests and parents’ estimates of daily language use and exposure of both languages) influenced EF performance. Accordingly, the relationship between CS and EF may be more indirect and non-necessary than previously assumed.
