Zusammenfassung
Research on subject-verb agreement during
comprehension suggests a ‘grammaticality asymmetry’ in similarity-based retrieval interference. Whereas processing costs incurred by ungrammatical subject-
verb agreement are reduced in the presence of a grammatically illicit attractor noun that matches the verb in number, attractor nouns have not been found
to affect the processing of grammatical sentences [1]. However, most existing studies have only included singular verbs in the grammatical conditions, and the
lack of retrieval interference in such cases could be a result of the fact that singular is an unmarked feature [2]. In the current study, we tested for similarity-based
interference for both singular and plural verbs in fully grammatical sentences. If plural is a marked feature, we expect to find evidence of retrieval interference for
plural verbs but not singular verbs when multiple items in memory match the number of the verb. We predicted
that retrieval interference would elicit a P600 effect [3-4], the effect commonly associated with syntactic processing difficulties. Methods: Participants read 120
grammatical sentences (30 per condition) belonging to a 2(subject noun: plural, singular) x 2(attractor noun: plural, singular) factorial design in which the critical verb (have/had/were/was) always agreed in number with the subject noun. PS: “The keys to the cabinet were
getting very rusty”, PP: “The keys to the cabinets were getting very rusty”, SS: “The key to the cabinet was getting very rusty”, SP: “The key to the cabinets was getting very rusty”. Sentences were mixed with 280 fillers and presented word by word (300 ms duration, 200 ms blank). Intermittent yes/no comprehension questions were answered with 92% accuracy. EEG data was
recorded from sixty-four channels and segmented into epochs from 200 ms before to 1000 ms verb onset. Data was baselined to 0-200 ms post-stimulus to eliminate
spurious effects from pre-critical word differences (see also [3-4]). Results: Using average amplitude per condition across 16 centrally distributed EEG electrodes,
repeated measures ANOVAs in the 500-700 ms time window showed an effect of attractor that was reliably different for plural and singular verbs (F(1,35)=4.8,
p<.05), with a robust P600 effect elicited by plural verbs (PP minus PS voltage difference, M=.64, F(1,35) = 5.7, p
< .05) but none for singular verbs (SS minus SP, M= -.22, F(1,35)=.44, ns). Conclusions: The observed P600 effect
for grammatically correct, plural verbs in context of a plural attractor noun suggests that retrieval interference arises as a by-product of grammatical processing, and
constitutes evidence against a grammaticality asymmetry in interference effects. References: [1] Wagers, M. W.,
Lau, E. F., & Phillips, C. (2009). Journal of Memory and Language [2] Bock, K., & Eberhard, K. M. (1993). Language and Cognitive Processes [3] Kaan, E. (2002).
Journal of Psycholinguistic Research [4] Tanner, D., Nicol, J., Herschensohn, J., & Osterhout, L. (2012). Proceedings
of the 36th Annual Boston University Conference on Language Development (pp. 594-606).
