Event-related brain potentials elicited by failure to agree

Event-related potentials (ERPs) were recorded from 13 scalp electrodes while subjects read sentences, some of which contained violations of number or gender agreement. Subjects judged the acceptability of sentences in Experiments 1 and 2 and passively read sentences in Experiment 3. In Experiment 1, violations of subject-verb number, reflexive-antecedent number, and reflex ive-antecedent gender agreement elicited a widely distributed positive-going wave (P600). Subject-verb agreement violations also elicited a left-hemisphere negativity In Experiment 2, personal pronouns that mismatched in gender with the subject noun elicited a P600, but only when subjects judged such sentences to be unacceptable. Semantically anomalous words elicited an enhanced N400 component. In Experiment 3, subject-verb number disagreement elicited a P600 and semantic anomalies elicited an enhanced N400. ERPs to reflexive-antecedent agreement violations did not differ from those to controls. We evaluate the speculation that agreement between sentence constituents reflects syntactic constraints rather than semantic or discourse factors. (C) 1995 Academic Press, Inc.