The duration of a brief event in the mind's eye.

A new illusion of perceived duration associated with focused spatial attention is reported. Brief flashes in attended locations were perceived to last longer than the same flashes in unattended locations. That illusion was shown to be completely independent of another illusion concerning the perceived onset of a flash, ruling out the possibility that the effect on perceived duration is derivative of a comparison between perceived onset and offset. The illusion also occurred when the event duration was composed of a temporal gap rather than a brief flash, ruling out low-level visible persistence as a basis for the illusion. Taken together, the results point to cortical connections from higher brain centers' both speeding and prolonging the visual signals occurring in lower sensory regions. Those temporal consequences could easily subserve many of the perceptual benefits ascribed to attention for spatial and intensive properties.