Beyond visible persistence: an alternative account of temporal integration and segregation in visual processing

When processing sequences of rapidly varying stimuli, the visual system must satisfy two conflicting requirements. To maintain perceptual continuity, sequential stimuli must be integrated into a single, unified percept. On the other hand, to detect rapid changes, sequential stimuli must be segregated from each other. We propose that these conflicting demands are reconciled by a process that codes the temporal relationship between contiguous stimuli: Stimuli that are coded as co-extensive are integrated and those that are coded as disjoint are segregated. This approach represents a conceptual departure from the more traditional "intrinsic persistence" view of temporal integration. The approach provides a parsimonious account of the results of two temporal-integration tasks in which the durations of the leading and trailing displays were varied over a broad range. The data were accurately fit by a quantitative model in which temporal codes were determined by the correlation in time between the visual responses to the leading and trailing displays.