Attentional disengagement suppresses visual long-term memory

Abstract

When a salient, task-irrelevant stimulus captures attention, we must disengage from it to resume goal-directed behavior. How is disengagement achieved? Several theories postulate that suppression of the distractor is necessary, although viable alternatives have been proposed. Here, we introduce a novel test for disengagement-related suppression, using a subsequent memory design. In Phase 1 (Incidental Memory Encoding), participants categorized a series of objects as living or non-living. In Phase 2 (Visual Search), participants searched for an oddball shape target while trying to ignore a salient color singleton. Critically, we placed an object from Phase 1 inside the color singleton; our goal was to assess how distractor disengagement would affect the memory representations of these objects. Based on intertrial priming studies, we anticipated that the salient distractors would elicit greater attention capture – and, consequently, more distractor disengagement – on trials in which the target switched vs. repeated its shape (compared to the previous trial). Thus, we could examine the effects of greater vs. lesser disengagement on objects that appeared during target switch vs. repeat trials. In Phase 3 (Surprise Perception/Memory Test), on each trial, participants were first shown a new or old object (from Phase 1), superimposed with a salt and pepper noise mask. We asked participants to gradually reduce the noise until they could identify the object, enabling us to assess its perceptual representation on a continuous scale. After identification, the object was fully unmasked, and participants then judged if it was new or old. If suppression accompanied distractor disengagement during Phase 2, then both perceptual identification and subsequent memory for the objects inside the distractor would be degraded. Indeed, results showed worse perceptual identification and recognition memory for items presented during Phase 2 target switches compared to target repetitions. We conclude that distractor disengagement is an inherently suppressive process. Meeting abstract presented at VSS 2016