An investigation of the unit of activation in on-line inferences during text processing: word-unit or proposition-unit?

This study investigated the unit of activation in on-line inferences. To explore whether the activation of inferences is a word-unit or a proposition-unit, a meaningfulness-decision task was devised as a priming measure. The task required participants to decide whether a series of short sentences was meaningful or not. The result of Experiment 1 suggested that only proposition-units were activated. A priming effect was observed in targets which described inferences both at word-level and proposition-level, but not in targets which described inferences at word-level only. In Experiment 2, a meaningfulness-decision task was administered to investigate word-based priming and to make sure that the result of Experiment 1 was not caused by characteristics of the task. In Experiment 3, a priming effect was found in targets which described inferences using alternative perspectives and words. These results suggest that the unit of activation in on-line inferences is proposition-units and that these activations relate to the proposition-semantic level, not the word or single-concept level.