While language-switching in the lab localizes in anterior cingulate cortex, comprehending code-switches in the wild begins in auditory cortex: MEG evidence from Arabic-English bilinguals

Blanco-Elorrieta, E. 1 & Pylkkänen, L. 1, 2

1 New York University Department of Psychology
2 New York University Department of Linguistics

While the ability to fluently code-switch is a hallmark of bilingualism, the neurobiology of this ability has primarily been explored with designs that make code-switching quite hard, involving artificial cues for switching. This contrasts starkly with the intuitive ease of naturally occurring switching. We investigated the spatio-temporal profile of language switching in natural conversation and compared this to artificially cued switching. To bridge the gap between these two extremes, we included two more natural lab-switching tasks, modeled according to dense-code-switching (bilingual interlocutors interleaving languages freely) and dual-language-switching (both languages are used but with different speakers). Our results showed that within the laboratory tasks, but not the natural conversation, activity increased for switches in the anterior cingulate cortex (ACC) in both production and comprehension across all contexts. In conversation, switch-effects instead localized in auditory cortices at 50-150ms post switch-onset. Finally, within the laboratory tasks, we observed an increase in bilateral ACC for the dual and dense situations as compared to artificial color-cues. In sum, this study shows a dissociation between switching in a natural vs. a laboratory context and that the introduction of a social context into a laboratory task increases the involvement of the ACC, hypothesized to reflect conflict resolution.