The Modulatory Effect of Expectations on Memory Retrieval During Sentence Comprehension

Memory retrieval and probabilistic expectations are recognized factors in sentence comprehension that capture two different critical aspects of processing difficulty: the cost of retrieving and integrating previously processed elements with the new input words and the cost of incorrect predictions about upcoming words or structures in a sentence. Although these two factors have independently received substantial support from the extant literature, how they interact remains poorly understood. The present study investigated memory retrieval and expectation in a single experiment, pitting these factors against each other. Results showed a significant interference effect in both response time to the comprehension questions and reading time at the last (spillover) sentence region. We also found that the interference effect on reading time (but not on comprehension question response time) was canceled when the word at the retrieval site was highly predictable. Overall, our findings are consistent with the hypothesis of a modulatory effect of expectations on memory retrieval and with the idea that expectation-based facilitation results from pre-activation of the target word ahead of time.