Number agreement in sentence comprehension: The relationship between grammatical and conceptual factors

Studies in theoretical linguistics argue that subject-verb agreement is more sensitive to grammatical number, while pronoun-antecedent agreement is more sensitive to conceptual number. This claim is robustly supported by speech production research, but few studies have examined this issue in comprehension. We investigated this dissociation between conceptual and grammatical number agreement in three eye-tracking reading experiments, using collective nouns like “group”, which can be notionally interpreted as either singular or plural. Experiment 1 indicated that pronoun-antecedent agreement is conceptually driven; Experiment 2 indicated that subject-verb agreement is morpho-syntactically driven. Experiment 3 indicated that the morpho-grammatical processes that control the initial processing of subject-verb agreement do not bias later semantic processing of pronoun-antecedent number agreement, even when the anaphor and the verb occur in the same sentence, and the same collective noun is both the subject of the verb and antecedent of the pronoun. In view of these findings we propose that the processes that control number agreement in comprehension show a dissociation between semantic and morpho-syntactic processing that is similar to the dissociation demonstrated in speech-production. We discuss various theoretical frameworks that can account for this similarity.