Midgley, K. 1, 2 , Holcomb, P. J. 1 & Grainger, J. 1, 2
1 Department of Psychology, Tufts University, Medford, MA, USA
2 Centre National de la Recherhce Scientifique, Université de Provence, Marseille, France
Whether in production or comprehension, bilinguals can and do freely switch between their two languages. What are the processing costs and underlying neural mechanisms associated with these language switches? We investigated this by presenting, in the auditory modality, common, single-word non-cognates in English and French to 24 native French speakers who were learning English at university. Critical items were either “switch” items, for which the language differed from the two previously-presented words (CLAVIER - POMME - BEACH) or they were “non-switch” items, in which case the language remained the same across the previously-presented words (WINDOW - FIGHT - DRINK). Event-related potentials were recorded from 32 scalp electrodes to each critical, final item (BEACH compared to DRINK). Consistent with previous research by our group we found a widespread language effect with larger negativities to words in L1 relative to L2 in an extended epoch starting at 150ms and continuing 600ms. As concerns language switching L1 items showed early effects of switching between 150 and 250ms with switch items producing more negative-going ERPs over left posterior regions than non-switch items. There were also later effects of language switching that were more widespread across the scalp and appeared to be centered on the classic N400 (switch items again more negative than non-switch). No effects of switching were found for L2 items. These results appear to be consistent with theories postulating a greater inhibition of the dominant L1 during L2 processing followed by a need for greater reactivation of L1 after a switch. The findings will be discussed within the framework of current models of bilingual language control.