When one pseudoword elicits larger P600 than another: a study on the role of reprocessing in anomalous sentence comprehension

Reprocessing has been speculated to be a late higher-level cognitive process in the P600 time window in event-related potential (ERP) studies. However, uncertainties regarding the P600 as an index of reprocessing have obscured the role of reprocessing in sentence comprehension. In this study, we compared meaningless pseudowords with or without a homophonic repairing clue (homophonic pseudoword vs. ordinary pseudoword) and semantically-plus-syntactically violated real words (doubly violated) to investigate the role of reprocessing in language comprehension. All anomalous conditions elicited significant typical central-parietal P600 effects. The homophonic pseudoword condition elicited a significantly larger P600 effect than the other two anomalous conditions. No significant difference was found between the P600 effects in the ordinary pseudoword and the doubly violated real-word conditions. These results demonstrate an association between reprocessing and the observed P600 effects, supporting an active role of reprocessing in sentence comprehension. Possible implications for language processing models are also discussed.