Memory retrieval in discourse: Illusions of coherence during presupposition resolution

Syntactically inaccessible distractors can cause an illusion of grammaticality during the resolution of syntactic dependencies. At the discourse level, there is also a notion of accessibility. To what extent is this notion relevant to the processing of dependencies that go beyond the syntactic level? In three eye-tracking experiments, we studied illusion effects during presupposition resolution in short discourses. A sentence in the discourse triggered a presupposition, and a preceding sentence provided two candidate propositions for resolution: a target proposition that was accessible for presupposition resolution, and a distractor proposition that was inaccessible for the presupposition. Orthogonal to the accessibility manipulation, the two propositions could match or mismatch the semantic content of the presupposition. Experiment 1, focusing on the retrieval of gender features, showed an illusion effect by matching, but inaccessible, distractors, comparable to illusion effects in syntactic dependency resolution. In Experiment 2, which required the retrieval of compositional semantic information rather than a single feature, we replicate the finding that discourse-inaccessible information still influences memory retrieval in dependency resolution. In Experiment 3 we compared proactive and retroactive interference and demonstrated that the illusion effect is diminished or possibly even entirely disappears when the distractor is further away from the presupposition. We argue that our findings provide evidence that memory models deployed for syntactic retrieval should be extended to account for retrieval in discourses. This is challenging for most models of retrieval, more so for models that tie memory failures directly to (morpho-)syntactic structure building. We also indicate how a more general model of memory, the cue-based retrieval model, would have to be extended to capture our findings.