Alexandre Chauvin (Concordia University) & Natalie Phillips (Concordia University)
alexandre.bchauvin@gmail.com
Bilingualism; Bilingual advantage; Cognitive control; Executive control; Code-switching; Event-related brain potentials (ERP); Individual differences
Evidence suggests that bilinguals exhibit superior cognitive control compared to monolinguals by using a flexible combination of proactive processes (monitoring for relevant cues) and reactive processes (inhibiting irrelevant information) to cope with interference from the non-target language1This flexibility may be related to individual differences in language-switching behaviours, bilingual proficiency, age of acquisition of the second language (L2), or general executive functioning.
We used event-related brain potentials (ERPs) to examine proactive and reactive control processes in 15 young adult bilinguals (English-French or French-English; mean age = 24; mean self-rated proficiency: L1 = 4.84/5; L2 = 3.8/5) during the AX-CPT task. Participants were presented with the following cue-target letter pairs: A-X, A-Y, B-X, or B-Y (where B and Y are any letter other than A or X). The task was to press the “yes” key to an X target only if preceded by an A cue; all other targets should elicit a “no” response. There was a 750 millisecond interval between cue offset and target onset. We varied the global context of each block (70% A-X, 70% A-Y, 70% B-X), thus altering the degree to which proactive processes could be used to guide performance.
We hypothesized that participants would respond faster and more accurately to A-X pairs compared to A-Y pairs in the A-X-70% block due to the facilitating effect of the global block context (i.e., respond “yes” 70% of the time). In contrast, participants should respond slower and less accurately on A-X pairs compared to A-Y pairs in the A-Y-70% block. In terms of the electrophysiological data, cue-locked ERPs should reflect proactive processes whereas target-locked ERPs should primarily reflect reactive processes. Of particular interest is the N2 ERP component, a negative-going component that peaks 200-350 msec after the onset of a stimulus and is thought to be a marker of conflict detection2. We observed a larger target-locked N2 on A-Y trials compared to A-X trials in the AX-70% block. We hypothesize that this is due to the conflict between 1) the task set preparation as a function of both the cue and global context of the block (i.e., prepare “yes” response), and 2) the nature of the target (i.e., withhold “yes” response) . In contrast, we did not observe a significant target-locked N2 on A-Y trials in the A-Y-70% block because the prepared “no” response initiated by the cue is congruent with the information subsequently given by the target.
We will report the extent to which these behavioural and ERP effects are modulated by individual differences in language-switching behaviours, proficiency, age of acquisition of L2, and general executive functioning.
References
[1] Morales, J., Yudes, C., Gómez-Ariza, C. J., & Bajo, M. T. Bilingualism modulates dual mechanisms of cognitive control: Evidence from ERPs. Neuropsychologia, 66:157-169, 2014.
[2] Folstein, J., & Van Petten, C. Influence of cognitive control and mismatch on the N2 component of the ERP: a review. Psychophysiology, 45(1):152-170, 2008.
