Electrophysiological Explorations of the Bilingual Advantage: Evidence from a Stroop Task

Abstract

Bilinguals have been shown to exhibit a performance advantage on executive control tasks, outperforming their monolingual counterparts. Although a wealth of research has investigated this ‘bilingual advantage’ behaviourally, electrophysiological correlates are lacking. Using EEG with a Stroop task that manipulated the stimulus onset asynchrony (SOA) of word and colour presentation, the current study addressed two facets of the bilingual advantage. The possibility that bilinguals experience superior conflict processing relative to monolinguals (a ‘conflict-specific advantage’) was investigated by comparing behavioural interference effects as well as the amplitude of the Ninc, a conflict-related ERP component occurring from approximately 300–500 ms after the onset of conflict. In contrast, the hypothesis that bilinguals experience domain-general, conflict-independent enhancements in executive processing (a ‘non-conflict-specific advantage’) was evaluated by comparing the control condition (symbol strings) between groups. There was some significant, but inconsistent, evidence for a conflict-specific bilingual advantage. In contrast, strong evidence emerged for a non-conflict-specific advantage, with bilinguals demonstrating faster RTs and reduced ERP amplitudes on control trials compared to monolinguals. Importantly, when the control stimulus was presented before the colour, ERPs to control trials revealed group differences before the onset of conflict, suggesting differences in the ability to ignore or suppress distracting irrelevant information. This indicates that bilinguals experience superior executive processing even in the absence of conflict and semantic salience, and suggests that the advantage extends to more efficient proactive management of the environment.

Neural correlates of cognitive processing in monolinguals and bilinguals

“…In contrast, the Stroop task showed greater P3 amplitudes for monolinguals than bilinguals. Similarly, Coderre et al . reported greater P3 amplitudes for monolinguals than bilinguals during a Stroop task.…”

“…These ERP effects suggest that monolinguals might be devoting more resources at late stages of processing (interference control and response selection) than bilinguals to deal with conflict. In another study, Coderre et al . examined the N450 and found that bilinguals had smaller ERP Stroop effects than monolinguals with equal behavioral performance, again demonstrating that monolinguals are devoting more resources at late stages of processing compared with bilinguals.…”

Audio-visual object search is changed by bilingual experience

“…For example, group differences in eye-movement patterns (even in the absence of behavioral reaction time differences) may suggest that bilinguals and monolinguals employ distinct search strategies. Because bilinguals excel at focusing on task-relevant information (e.g., Coderre & Van Heuven, 2014), we expected eye-movements to reflect bilinguals’ ability to ignore non-target objects.…”

Neuroscience in Intercultural Contexts

“…This provides limited evidence for the presence of a confl ict-specifi c bilingual advantage. However, Coderre & van Heuven ( 2014a ) also observed group differences between bilinguals (in both languages) and monolinguals when comparing control trials, which contained no confl icting or facilitating information. Furthermore, these group differences observed in the negative SOA before the color had been presented, i.e.…”

“…The irrelevant distractor word could either appear just before the target color (a 'negative SOA'); just after (a 'positive SOA'; or at the same time (a '0 ms SOA'). Coderre & van Heuven ( 2014a ) found some signifi cant, but inconsistent, differences between monolinguals and bilinguals in a confl ict-related ERP component (the Ninc): bilinguals showed differences compared to monolinguals when performing this Stroop task in their L1 but not their L2. This provides limited evidence for the presence of a confl ict-specifi c bilingual advantage.…”