Temporal dynamics and readout latency in perception and iconic memory

After the offset of complex visual stimuli, rich stimulus information remains briefly available to the observer, reflecting a rapidly decaying iconic memory trace. Here we found that even if the cues are presented in the final stage of the stimulus presentation, the reportable information already starts decaying. Using closely spaced readout cues and a theoretical model of information availability, we observed that a cue has to be presented around 10 to 30 milliseconds before stimulus offset to access the full sensory information. We suggest that this does not reflect an early loss in sensory encoding, but instead it is a consequence of a latency in the processing of the cue that postpones the readout of the sensory representation by 10 to 30 milliseconds. Our analysis also shows that spatial proximity of items in complex arrays impacts sensory representation during both perceptual encoding and initial memory decay. Overall, these results provide a theoretical and empirical characterization of the readout from visual representations and offer a detailed insight into the transition from perception into iconic memory.