Cognitive control states influence real-time sentence processing as reflected in the P600 ERP

As sentences unfold, people often encounter conflicting cues that vie for influence during processing and comprehension. We measured event-related potentials (ERPs) to test the hypothesis that cognitive control increases activation of the most plausible analysis of the input to resolve such conflicts. Participants read sentences like "The bathroom floor was mopping yesterday", where conflict arises between a syntactically-licensed interpretation ("floor" as Agent of "mop") and a semantically plausible one ("floor" as Theme of "mop"). Participants also completed pseudorandomly interleaved Congruent and Incongruent Stroop trials, which manipulated cognitive-control engagement immediately before sentence-reading trials. Target sentences elicited a P600 effect, replicating previous results suggesting that readers typically make morphosyntactic edits to yield the plausible interpretation (e.g. "mopping" -> "mopped"). Crucially, the P600 was larger and more broadly distributed following Incongruent versus Congruent Stroop items, consistent with increased structural repair activity when an individual's state of cognitive control is relatively upregulated.