Investigating a memory-based account of negative priming, support for selection-feature mismatch

grantor: University of TorontoNegative priming is defined as a delay in responding to a stimulus that was recently ignored. To study negative priming, the typical paradigm involves presenting two sequential displays: a prime display followed by a probe display. For each, participants are normally asked to select a target and to ignore a distractor. When the target item on the probe was previously the distractor on the prime, responding is slowed relative to when neither the target nor the distractor was repeated. This delay is used as an index of the processing of unattended information. Experiments 1A-3B tested whether ignoring distractors on the prime display is a necessary condition for negative priming. The effect of requiring participants to attend to distractors was investigated. When participants were asked to select the name of the larger animal in a word pair--requiring deep processing of the distractor--the standard negative priming effect was quadrupled. Negative priming not only persisted for attended distractors, it actually was enhanced. Further, this inflated effect was not due solely to increased latencies in the novel referent size-selection task because neither decreasing base response times in other referent size-selection tasks nor increasing base response times in typical colour-selection tasks substantially affected the respective negative priming scores. These findings challenge the basic assumption that negative priming arises because the repeated item was first ignored on the prime. The second aim was to differentiate competing explanations of negative priming, using both the typical colour-selection procedure and the referent size-selection task. In Experiments 4-6, negative priming only occurred when the repeated item mismatched from the prime to the probe in terms of the feature used as the basis for selection. When the repeated item was congruent on the selection dimension across successive displays, positive priming resulted. This pattern of results occurred whether the repeated item was the distractor or the target on the prime, further dismissing the notion that negative priming results from previously ignoring an item. These findings strongly support the selection-feature mismatch account of negative priming and refute both the distractor inhibition and the episodic retrieval explanations.Ph.D