Exploring the abstractness of number retrieval cues in the computation of subject-verb agreement in comprehension

Subject-verb agreement has provided critical insights into the cue-based memory retrieval system that supports language comprehension by showing that memory interference can cause erroneous agreement with non-subjects: 'agreement attraction'. Here we ask how faithful retrieval cues are in relation to the grammar. We examine the impact of conjoined singular attractors (The advice from the doctor and the nurse…), which are syntactically plural but whose plurality is introduced by a vehicle, the conjunction 'and', that is not an unequivocal correlate of syntactic plurality. We find strong agreement attraction, which suggests that retrieval processes do not only target unequivocal morphological correlates of syntactic plurality. However, we also find some attraction with conjoined adjective attractors (The advice from the diligent and compassionate doctor…), which is compatible with a system in which an imperfect correlate of syntactic plurality, like the word 'and', can become associated with the plural retrieval cue due to frequent co-occurrence with the actual target feature.