Event-Related Potential Differences Between Cognition in Bilinguals’ L1 and L2: A Scoping Review

Research has shown that language impacts cognition across various domains. Accumulating evidence suggests that multilinguals are less emotionally reactive in an acquired language (L2) than a native language (L1), and that bilinguals undergoing psychiatric assessment may present with fewer symptoms in L2 than L1. This scoping review provides an overview of studies using event-related potentials (ERPs) to compare bilinguals’ neural activity when performing the same cognitive tasks in their L1 and L2. Given the review’s broad inclusion criteria, hypotheses were posed at a broad level: 1) that ERP amplitudes would be greater in participants’ L2 than in their L1, and 2) that ERP latencies would be longer in participants’ L2 than in their L1. A systematic search of the PsycInfo database identified 69 potentially relevant records, of which eight were included, together reporting ERP data for 202 participants. Studies showed considerable heterogeneity in participant languages spoken, cognitive tasks employed, ERP components studied, and analyses performed on the ERP components. Across studies, there was no consistent pattern for amplitudes, which were variously greater in L2, greater in L1, or not significantly different. In contrast, longer ERP latencies in L2 relative to L1 were reported in all but one study, supporting the review’s second hypothesis. These findings give a snapshot of current evidence on the topic, while demonstrating the need for further research replicating and extending existing results.