Conflict resolution in sentence processing by bilinguals

The present study pursues findings from earlier behavioral research with children showing the superior ability of bilinguals to make grammaticality judgments in the context of misleading semantic information. The advantage in this task was attributed to the greater executive control of bilinguals, but this impact on linguistic processing has not been demonstrated in adults. Here, we recorded event-related potentials in young adults who were either English monolinguals or bilinguals as they performed two different language judgment tasks. In the acceptability task, participants indicated whether or not the sentence contained an error in either grammar or meaning; in the grammaticality task, participants indicated only whether the sentence contained an error in grammar, in spite of possible conflicting information from meaning. In both groups, sentence violations generated N400 and P600 waves. In the acceptability task, bilinguals were less accurate than monolinguals, but in the grammaticality task which requires more executive control, bilingual and monolingual groups showed a comparable level of accuracy. Importantly, bilinguals generated smaller P600 amplitude and a more bilateral distribution of activation than monolinguals in the grammaticality task requiring more executive control. Our results show that bilinguals use their enhanced executive control for linguistic processing involving conflict in spite of no apparent advantage in linguistic processing under simpler conditions.