Magnetoencephalography detection of early syntactic processing in humans: comparison between L1 speakers and L2 learners of English

Abstract

In previous brain imaging studies of human syntax processing, only phrase structure (grammatical category) violations have been shown to elicit a very early (∼140 ms) neural response. This has led to interpretations about the nature of phrase structure encoding in the brain, particularly its relationship to early automatic brain processes. Utilizing different sentence structures that contrasted within- vs. across-phrase violations, the current study examined whether an early response could be elicited by non-phrase-structure violations. Magnetoencephalography fields were recorded, while both first-language speakers (L1) and second-language learners (L2) were tested. A prominent syntactic magnetic field component, peaking at around 150 ms post-onset (labeled ‘SF-M150’), was observed in both hemispheres of only the L1 speakers in response to within-phrase violations but not across-phrase violations. The results provide evidence that L1 speakers possess the ability for automated detection of non-phrase-structure violations, particularly within-phrase violations, and that L2 learners may not have sufficient neural representation available for an early automated response to the target violations.