The interaction of notional number and morphophonology in subject-verb agreement: A role for working memory.

Research shows that cross-linguistically, subject-verb agreement with complex noun phrases (e.g., The label on the bottles) is influenced by notional number and the presence of homophony in case, gender, or number morphology. Less well-understood is whether notional number and morphophonology interact during speech production, and whether the relative impact of these two factors is influenced by working memory capacity. Using an auditory sentence completion task, we investigated the impact of notional number and morphophonology on agreement with complex subject noun phrases in Dutch. Results revealed main effects of notional number and morphophonology. Critically, there was also an interaction between morphophonology and notional number because participants showed greater notional effects when the determiners were homophonous and morphophonologically ambiguous. Furthermore, participants with higher working memory scores made fewer agreement errors when the subject noun phrase contained homophonous determiners, and this effect was greater when the subject noun phrase was notionally singular. These findings support the hypothesis that cue-based retrieval plays a role in agreement production, and suggests that the ability to correctly assign subject-verb agreement-especially in the presence of homophonous determiners-is modulated by working memory capacity.

Agreement With Conjoined NPs Reflects Language Experience.

An important question within psycholinguistic research is whether grammatical features, such as number values on nouns, are probabilistic or discrete. Similarly, researchers have debated whether grammatical specifications are only set for individual lexical items, or whether certain types of noun phrases (NPs) also obtain number valuations at the phrasal level. Through a corpus analysis and an oral production task, we show that conjoined NPs can take both singular and plural verb agreement and that notional number (i.e., the numerosity of the referent of the subject noun phrase) plays an important role in agreement with conjoined NPs. In two written production tasks, we show that participants who are exposed to plural (versus singular or unmarked) agreement with conjoined NPs in a biasing story are more likely to produce plural agreement with conjoined NPs on a subsequent production task. This suggests that, in addition to their sensitivity to notional information, conjoined NPs have probabilistic grammatical specifications that reflect their distributional properties in language. These results provide important evidence that grammatical number reflects language experience, and that this language experience impacts agreement at the phrasal level, and not just the lexical level.