Processing polarity items 1 Running head: HOW THE UNGRAMMATICAL INTRUDES ON THE GRAMMATICAL Processing Polarity: How the ungrammatical intrudes on the grammatical

A central question in online human sentence comprehension is: how are linguistic relations established between different parts of a sentence? Previous work has shown that this dependency resolution process can be computationally expensive, but the underlying reasons for this are still unclear. We argue that dependency resolution is mediated by cue-based retrieval, constrained by independently motivated working memory principles defined in a cognitive architecture (ACT-R). To demonstrate this, we investigate an unusual instance of dependency resolution, the processing of negative and positive polarity items, and confirm a surprising prediction of the cue-based retrieval model: partial cue-matches—which constitute a kind of similarity-based interference—can give rise to the intrusion of ungrammatical retrieval candidates, leading to both processing slowdowns and even errors of judgment that take the form of illusions of grammaticality in patently ungrammatical structures. A notable achievement is that good quantitative fits are achieved without adjusting the key model parameters.