Speech rate and associations in predictive sentence processing

Do comprehenders predict (i.e., what will come next) when hearing rapid speech? Two mouse cursor tracking experiments investigated association-based predictions, which may be suited to speeded processing. Participants heard predictive sentences (e.g., "What the pilot will fly, which is shown here, is the . . .") while viewing visual arrays with predictable objects (e.g., helicopter) and unpredictable but verb-associated objects (e.g., kite) or unrelated objects (e.g., book). Experiment 1 compared predictive and nonpredictive (e.g., "What everyone will discuss, which is shown here, is the . . .") sentences at a normal speech rate, and Experiment 2 compared predictive sentences at a normal and fast speech rate (e.g., averaging ~4 and 9 syllables per second). In addition to making mouse cursor movements to predictable objects before hearing predictable words (e.g., "helicopter"), participants' mouse cursor movements at both speech rates were attracted to unpredictable but verb-associated objects, providing evidence of association-based prediction. These results suggest that when hearing rapid speech, associations support but do not dominate comprehenders' predictions.