The Relationship Between Second Language Proficiency and Neurocognitive Processing

The relationship between second language (L2) proficiency and neurocognitive processing has been largely discussed. Previous research has shown that L2 proficiency may modulate the amplitude and latency of the P600 effect, an event-related potential (ERP) component typically observed in response to (morpho)syntactic violations. Studies indicate that learners with higher proficiency tend to exhibit larger P600 effects, evidencing a more robust processing. 

This study examines whether and how proficiency modulates adult L2 learners’ brain responses in (morpho)syntactic processing in an ERP experiment. 22 intermediate-to-advanced L2 learners of Spanish completed two aural and written tasks to measure their proficiency in Spanish: an elicited imitation task (EIT) and a modified version of an standardized test, the DELE. Furthermore, electroencephalograms were recorded while participants completed a grammaticality judgment task (GJT), including four experimental conditions: phrase structure (PS), subject-verb agreement (SV), noun-phrase number agreement (NPn), and gender agreement (NPg).

Preliminary ERP analyses showed apparent P600 effects for NPn and NPg, whereas no clear effects were elicited for PS or SV, although small positivities suggest individual variation. To determine the role of proficiency in L2 processing, a correlation analysis was conducted between EIT and DELE, and the amplitude of the P600. Results evidenced a significant positive correlation between EIT and P600 for PS (r = .53) , and a significant positive correlation between DELE and P600 for NPn (r = .58) and NPg (r = .49). Furthermore, a significant positive correlation was found between EIT and DELE (r = .58). Overall, these preliminary results are consistent with previous research, by suggesting that proficiency modulates the amplitude of the P600 effect when processing (morpho)syntactic structures: lower proficiency is associated with smaller P600 effects, whereas higher proficiency is related to larger P600s. Ongoing data collection and analyses will further inform whether these associations are found across linguistic conditions.