Language and task switching in the bilingual brain: Bilinguals are staying, not switching, experts

• Published in: Neuropsychologia Vol. 66; no. Jan; pp. 193 - 203
• Main Authors: Weissberger, Gali H., Gollan, Tamar H., Bondi, Mark W., Clark, Lindsay R., Wierenga, Christina E.
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.01.2015
• Subjects: Adult; Bilingualism; Brain; Brain - physiology; Brain Mapping; Code Switching; College Students; English; Executive control; Executive Function - physiology; Female; fMRI; Functional Magnetic Resonance Imaging; Humans; Interference; Linguistic control; Magnetic Resonance Imaging; Male; Multilingualism; Spanish; Task switching; Verbal Tasks; Young Adult; Task switching; fMRI; Bilingualism; Executive control; Linguistic control
• ISSN: 0028-3932; 1873-3514; 1873-3514
• DOI: 10.1016/j.neuropsychologia.2014.10.037

Bilinguals' ability to control which language they speak and to switch between languages may rely on neurocognitive mechanisms shared with non-linguistic task switching. However, recent studies also reveal some limitations on the extent control mechanisms are shared across domains, introducing the possibility that some control mechanisms are unique to language. We investigated this hypothesis by directly comparing the neural correlates of task switching and language switching. Nineteen Spanish–English bilingual university students underwent a functional magnetic resonance imaging (fMRI) study employing a hybrid (event-related and blocked) design involving both color-shape switching and language switching paradigms. We compared the two switching tasks using within-subject voxel-wise t-tests for each of three trial types (single trials in single blocks, and stay and switch trials in mixed blocks). Comparing trial types to baseline in each task revealed widespread activation for single, stay, and switch trials in both color-shape and language switching. Direct comparisons of each task for each trial type revealed few differences between tasks on single and switch trials, but large task differences during stay trials, with more widespread activation for the non-linguistic than for the language task. Our results confirm previous suggestions of shared mechanisms of switching across domains, but also reveal bilinguals have greater efficiency for sustaining the inhibition of the non-target language than the non-target task when two responses are available. This efficiency of language control might arise from bilinguals' need to control interference from the non-target language specifically when not switching languages, when speaking in single- or mixed-language contexts. •Authors examined the relationship between bilingual language-switching and task-switching.•Single/stay/switch trials were compared across tasks.•Greatest differences in activation were found between language stay and color-shape stay trials.•Findings suggest greater efficiency for maintaining 2 languages, than 2 non-linguistic tasks available for response.•Bilinguals are experts at “staying” in a single language when faced with linguistic alternatives.