The role of language production in making predictions during comprehension

Language comprehension depends heavily upon prediction, but how predictions are generated remains poorly understood. Several recent theories propose that these predictions are in fact generated by the language production system. Here, we directly test this claim. Participants read sentence contexts that either were or were not highly predictive of a final word, and we measured how quickly participants recognised that final word (Experiment 1), named that final word (Experiment 2), or used that word to name a picture (Experiment 3). We manipulated engagement of the production system by asking participants to read the sentence contexts either aloud or silently. Across the experiments, participants responded more quickly following highly predictive contexts. Importantly, the effect of contextual predictability was greater when participants had read the sentence contexts aloud rather than silently, a finding that was significant in Experiment 3, marginally significant in Experiment 2, and again significant in combined analyses of Experiments 1-3. These results indicate that language production (as used in reading aloud) can be used to facilitate prediction. We consider whether prediction benefits from production only in particular contexts and discuss the theoretical implications of our evidence.