The effect of task complexity on linguistic and non-linguistic control mechanisms in bilingual aphasia

Abstract

In this study we examined linguistic and non-linguistic control mechanisms in 20 Spanish–English neurologically healthy bilingual adults and 13 Spanish–English bilingual adults with aphasia. Participants completed two linguistic and two non-linguistic control tasks accounting for low and high complexity. Healthy bilingual results were indicative of domain general cognitive control, whereas patient results were indicative of domain specific cognitive control. The magnitude of conflict required to complete the tasks was also examined. Healthy bilinguals exhibited significant amounts of conflict on all tasks and linguistic and non-linguistic conflict ratios were correlated; whereas patient results revealed significant conflict only on non-linguistic tasks and those conflict ratios were not correlated with linguistic conflict ratios, indicating a dissociation between how patients are controlling information in these two domains. Finally, a relationship between language impairment and language control was identified and brain damage was associated with linguistic and non-linguistic task performance.