No compelling evidence for a bilingual advantage in switching or that frequent language switching reduces switch cost

Participants completed three cued-switching tasks, responded to two category-fluency probes, two letter-fluency probes, and two probes to alternate between two targets. Correlations across the three cued-switching tasks were significant for both switching costs and mixing costs. The bilingual advantage hypothesis was tested both by forming language groups and treating bilingualism as a continuous variable. No bilingual advantages were observed. In verbal-fluency monolinguals generated more correct responses but the bilingual disadvantage on the category task was not reduced in the letter-fluency scores. The bilingual disadvantage was eliminated when the groups were matched on vocabulary size. The verbal-fluency measures obtained when participants alternated between targets weakly correlated with the switching-costs obtained in the cued-switching tasks.