Event-related brain potential evidence that local nouns affect subject–verb agreement processing

Abstract

The conditions under which speakers make syntactic errors, and the manner in which listeners respond to them, provide insight into how complex computational problems related to the rules of language are solved. One of the important syntactic rules of English is that a subject and its corresponding verb must agree in number. However, the presence of a number-bearing element between the subject and verb results in frequent production errors and has also been shown to complicate comprehension. When asked to press a button in response to anomalies in several narrated short stories, participants in the current study were better able to detect subject–verb agreement violations when there were no intervening words. In a separate event-related potential (ERP) experiment in which participants listened to the same stories for comprehension, simple subject–verb agreement violations elicited the predicted anterior negativity and later posterior positivity (P600). In contrast, when a singular noun phrase appeared between a singular subject and the corresponding verb, agreement violations elicited an early negativity with a distinctly posterior distribution. When a singular subject was followed by a plural noun phrase, there were no differences evident in ERPs elicited by singular and plural verbs. These results indicate that during comprehension of natural speech, the computation of subject–verb agreement is affected by the presence of number-bearing elements other than the subject itself.