In the current study, we evaluated behavioral and electrophysiological evidence to determine whether bilinguals differ from monolinguals in the efficiency of response inhibition. Bilinguals and matched monolingual controls performed the flanker task while behavioral and electrophysiological measures were collected. Participants were slower and less accurate in responding to incongruent trials, but the magnitude of the behavioral effect of congruence was not modulated by participant group. The electrophysiological data revealed a biphasic N200/P300 signature. Incongruent trials elicited a larger N200 response, followed by a larger P300 response than congruent trials. The mean amplitude of the N200 component, a marker of conflict detection, was not modulated by group, suggesting that monolinguals and bilinguals did not differ on the ability to detect conflict. However, the mean amplitude of the P300 component, an index of response inhibition, was smaller in bilinguals than monolinguals. This indicates that bilinguals may be more efficient in resolving response conflict relative to monolinguals. Even though the two groups do not differ in behavioral task performance, the event-related potential (ERP) data suggest that monolinguals may be working harder to reach similar patterns of performance as bilinguals. The P300 magnitude correlated positively with picture naming latencies and negatively with Operation Span scores, suggesting that the ERP response to nonlinguistic conflict resolution may capture individual differences in language proficiency and cognitive resources.
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