Syntactic Intervention cannot explain agreement attraction in English wh-questions

A core goal of psycholinguistics is to account for how syntactic constraints -- those that govern whether sentences in a language are grammatical or not -- are enforced during real-time processing. One such constraint in Mainstream American English is subject-verb agreement, which requires the verb's number feature matches that of its subject, irrespective of the number of any other noun phrases in the sentence. Past work has demonstrated that participants often make errors when enforcing this constraint when distractor noun phrases, called attractors, have a number feature different from the subject. Franck, Lassi, Frauenfelder & Rizzi (2006) propose an account of agreement errors based on the position of a potential attractor in a sentence's structural derivation in modern syntactic theory. In this paper, we argue that their account predicts that we should see no agreement attraction for a particular construction in English, a Discourse-linked wh-question. In a high-powered self-paced reading study, we test that prediction and find a robust attraction effect, suggesting that syntactic intervention is not a necessary condition for attraction errors in comprehension