Are cleft sentence structures more difficult to process?

This study compares the processing of cleft structures against that of monoclausal sentences using event-related potential (ERP). We aim to understand how syntactic complexity is processed by comparing the neural response to cleft and single-clause sentences with identical verb phrases, controlling for verb bias frequency effects. Sixty participants were tested, and we presented 100 cleft and 100 monoclausal sentences, balanced for active and passive verb usage. We examined the P600 component, an ERP associated with syntactic complexity, to assess the processing of cleft structures. Results showed that cleft structures incur a greater processing load, as indicated by a larger P600, compared to monoclausal sentences. The P600 response indicates that processing cleft sentences requires additional syntactic operations, consistent with behavioral studies showing that clinical populations have difficulty comprehending complex sentences.