How Is Sentence Processing Affected by External Semantic and Syntactic Information? Evidence from Event-Related Potentials

Abstract

Background: A crucial question for understanding sentence comprehension is the openness of syntactic and semantic processes for other sources of information. Using event-related potentials in a dual task paradigm, we had previously found that sentence processing takes into consideration task relevant sentence-external semantic but not syntactic information. In that study, internal and external information both varied within the same linguistic domain-either semantic or syntactic. Here we investigated whether across-domain sentence-external information would impact within-sentence processing. Methodology: In one condition, adjectives within visually presented sentences of the structure [Det]-[Noun]-[Adjective]- [Verb] were semantically correct or incorrect. Simultaneously with the noun, auditory adjectives were presented that morphosyntactically matched or mismatched the visual adjectives with respect to gender. Findings: As expected, semantic violations within the sentence elicited N400 and P600 components in the ERP. However, these components were not modulated by syntactic matching of the sentence-external auditory adjective. In a second condition, syntactic within-sentence correctness-variations were combined with semantic matching variations between the auditory and the visual adjective. Here, syntactic within-sentence violations elicited a LAN and a P600 that did not interact with semantic matching of the auditory adjective. However, semantic mismatching of the latter elicited a frontocentral positivity, presumably related to an increase in discourse level complexity. Conclusion: The current findings underscore the open versus algorithmic nature of semantic and syntactic processing, respectively, during sentence comprehension. © 2010 Schacht et al.