Phi-features reloaded: An event-related potential study on person and number agreement processing

ABSTRACT Linguistic analysis claims that verb agreement is composed of distinct phi-features such as person and number, but are these different phi-features processed distinctly or similarly? We used a sentence grammaticality task to explore the electrophysiological responses of Basque speakers when processing subject–verb person and number phi-feature agreement violations. We generated grammatical structures (grammatical control) and ungrammatical structures in which the verb disagreed with the subject in person (person violation), in number (number violation), or in both person and number features (person+number violation). Behavioral data revealed that, overall, participants were faster and more accurate detecting person and person+number violations than violations involving only number. Event-related potential responses revealed a N400–P600 pattern for all violation types. Person and person+number violations elicited larger P600 effects than number violations. These findings reveal different costs related to the processing of person and number phi-feature agreement and indicate that these features are distinct components of agreement computation.