The neural correlates of conflict detection and resolution during multiword lexical selection: Evidence from bilinguals and monolinguals

Previous studies have identified the Event Related Potential (ERP) components of conflict detection and resolution mechanisms in tasks requiring lexical selection at the individual word level. We investigated the brain potentials associated with these mechanisms in a lexical selection task based on multiword units made up of verb-noun combinations (e.g., eat breakfast, skip school). Native and non-native English speakers were asked to select a familiarized target verb-noun sequence (eat breakfast) between two choices. Trials were low-conflict, with only one plausible candidate (e.g., eat - shoot - breakfast) or high-conflict, with two plausible verbs (e.g., eat - skip - breakfast). Following the presentation of the noun, native English speakers showed a biphasic process of selection, with a conflict-detection centro-parietal negativity between 500 and 600 ms (Ninc), followed by a right frontal effect (RFE) between 600 and 800 ms preceding responses. Late Spanish-English bilinguals showed a similar but more sustained and more widespread effect. Additionally, brain activity was only significantly correlated with performance in native speakers. Results suggest largely similar basic mechanisms, but also that different resources and strategies are engaged by non-native speakers when resolving conflict in the weaker language, with a greater focus on individual words than on multiword units.