Bilingual advantage in executive control when task demands are considered

To examine how task demands influence bilingual advantage in executive control over monolinguals, we tested 32 Chinese monolinguals and 32 Chinese-English bilinguals with four versions of a color-shape switching task. During switching trials, the task required participants to suppress one set of conflicting (or non-conflicting) responses and simultaneously to activate another set of conflicting (or non-conflicting) responses. The results showed that compared to monolinguals, (i) when suppressing conflicting responses or (ii) activating non-conflicting responses, bilinguals had significantly smaller switching costs though similar mixing costs; (iii) when suppressing one set of conflicting responses and simultaneously activating another set of conflicting responses, bilinguals had significantly smaller switching costs though larger mixing costs; and (iv) when suppressing one set of non-conflicting responses and simultaneously activating another set of non-conflicting responses, bilinguals had similar switching costs and mixing costs. These findings indicate that task demands affect bilingual advantage in executive control.