Fragile Memories for Fleeting Percepts
Our perceptual systems are exceptionally good at searching our sensory environments for salient stimuli. A key question is the extent to which this search is performed subliminally. We explore this using Rapid Serial Visual Presentation (RSVP), by comparing detection performance with the memory left for distractors, the stimuli that have to be rejected as non-targets in the process of searching for targets. Our findings are that “immediate” free recall of arbitrary distractors at RSVP rates is very poor, with a severe recency effect. Recognition performance was higher and less subject to recency, but still substantially lower than detection performance. We argue that these findings suggest that the brain subliminally searches for salient stimuli, and are also consistent with a theory we call the tokenized-percept hypothesis, which links conscious perception to the process of episodically marking experiences.