On the person-number distinction: Subject-verb agreement processing in Italian

•We investigated the processing of person and number agreement in Italian.•Agreement was manipulated to create person and number agreement violations.•Two self-paced reading experiments were conducted.•Reading times were significantly slower for person than number violations.•We propose a functional dissociation between the two person and number features.

Agreement is generally conceived as a syntactic dependency whose computation and comprehension processes deal with agreement features uniformly, without differentiating among them. However, different interpretive properties are associated with Person and Number. While Person expresses the status of an argument with respect to the participants in the speech act (e.g. speaker, addressee), Number refers to the cardinality of the subject argument (e.g. a singular vs. a plural entity). Two self-paced reading experiments were run to investigate the on-line processing of subject-verb agreement in Italian manipulating both the Person and Number Agreement factors. The results revealed a greater processing penalty for Person compared to Number agreement violations, which is interpreted as evidence for a separate access to the two features. Because it disrupts the evaluation of the perspective from which a sentence is reported, a Person violation can generate a more serious perturbation than a Number anomaly, which only changes the Number property of the subject of predication.