Agreement checking in comprehension: evidence from relative clauses

Work on agreement processing in comprehension in English has provided evidence that the plural feature is "specified" or "marked" and that the syntactic structure of the subject plays a role in checking features. It is argued here that the structure intervening between the subject and verb also plays a role in checking and that there is pressure to check features immediately. A self-paced reading study tested this proposal in a previously unstudied configuration: agreement between the verb in a subject relative clause (RC) and the relative clause head (e.g., the niece of the actors who was/were...). According to the Construal Hypothesis (Frazier and Clifton, 1995), the structural relation between the RC and head is not immediately fully specified (unlike, for example, the relation between the subject and verb of a main clause). Thus, at the point when an agreeing verb is processed, the structure underlying the check may not yet be fully specified. This assumption about structural processing, together with the proposal for agreement checking in comprehension predicts (1) that there will be a large asymmetry between the processing of singular and plural agreeing verbs in the RC (larger than those seen in direct subject-verb predication) and (2) that there could be a role for agreement in determining RC attachment. Clear evidence for the first prediction was found: evidence for the second was inconclusive.