Event-related potentials to violations of inflectional verb morphology in English.

Event-related brain potentials were recorded to morphologically correct and incorrect regular and irregular past tense verb forms presented in sentences and in lists. In the sentence context, all incorrect verb forms elicited a broadly distributed late posterior positivity, as well as a left anterior negativity (LAN) that was particularly pronounced for the incorrect irregulars. Using a single-word paradigm, we did not find a LAN for any of the incorrect verb forms but found an N400-like effect for all irregular verbs. In the sentence context, only the incorrect irregulars elicited a long-lasting, broadly distributed late positivity, reminiscent of the P600. For regular verbs, responses to incorrect forms produced smaller, more time restricted effects. These data show that morphological and syntactic violations produce similar patterns of brain activity, suggesting that these two systems engage cognitive processes with similar underlying neural substrates.