ERP correlates of a receptive language-switching task.

Previous research has shown large response time costs (in excess of 50 ms) when bilingual speakers switch predictably back and forth between naming items (a productive switching task) in their first (L1) and second languages (L2). A recent study using event-related potentials (ERPs) has shown that switching between languages is associated with activity over frontal (N2) and parietal (late positive complex) areas of cortex (Jackson, Swainson, Cunnington, & Jackson, 2001). Switching between naming in different languages requires a switch in both language representations and language-specific motor responses. The current study investigated a receptive (input) language-switching task with a common manual response. Number words were presented in L1 and L2, and participants were required to judge whether the words were odd or even (a parity judgement). Response costs were considerably reduced, and the frontal and parietal switch related activity reported in the productive switching task was absent. Receptive switching was associated with early switch-related activity over central sensors that were not language specific. These results are discussed in relation to the idea that there is no language-specific lexical selection mechanism. Instead the costs of receptive language switching may arise from outside the bilingual lexicon.