Morphological analysis in sentence processing: An ERP study

We examined the effects of syntactic (tense) violations occurring on regularly versus irregularly inflected verbs using event-related brain potentials (ERPs). Participants read sentences in which the main verb varied in terms of regularity (regular vs: irregular), frequency (high vs. low), and grammaticality (tense violation vs. no tense violation). For regular verbs, we found a reliable N400 effect for verb frequency and a reliable P600 effect for grammaticality, with no interaction between lexical frequency and grammaticality. For irregular verbs, we found interactions between lexical frequency and grammaticality, with tense violations on high-frequency forms (*will stood) eliciting a much earlier P600 response than tense violations on low-frequency forms (*will knelt). We discuss the implications of these results with respect to morphological parsing, the time course of syntactic feature analysis, and their consequent effects on temporal properties of ERP components.