L2 processing of sentences with or without filler-gap dependencies: an ERP evidence

The present study investigated how L2 learners process sentences with filler-gap (object relative clauses) or without filler-gap dependencies (appositive clauses) via ERP experiments. By recording 26 Chinese EFL learners’ electrophysical responses in comprehending two types of clauses differing in one segment, the study revealed varied EEG responses in the time window of 300–500 ms. The results showed that in comparison with object relative clauses, appositive clauses elicited a more negative N400. It indicates that in comparison with clauses with filler-gaps, clauses with relativizers but no filler-gaps elicit higher difficulty in meaning processing and possible integration. However, the two types of clauses do not display significant differences in other ERP components, i.e., P600. The findings suggest that L2 learners adopt the Direct Association Strategy in complex sentence processing, and meanwhile the difficulty led by the non-filler-gap sentence is attributed to the semantic integration, rather than the syntactic unexpectation. It thus contributes to the understanding of L2 learners’ processing strategies and the underlying reasons from separated semantic and syntactic levels.