The Role of Cue Type and Cue Duration in the Persistence of a Bound Form in Vision

the crowding effect is temporally dependent. Second, crowding occurs when a target and its flankers are both presented to one eye (monocular presentation) or when each is presented to a different eye (dichoptic presentation). Thus, crowding may occur at a single stage in the visual system. To test this, we measured the temporal dependence of crowding when the target and flanker stimuli were presented monocularly or dichoptically. A method of constant stimuli task revealed that crowding varied as a function of the target-flanker SOA for both monocularly and dichoptically presented stimuli. Crowding across conditions was optimal at an SOA of ~25 ms and there was a slight (~10-15 ms) asynchrony in the time courses of monocular and dichoptic crowding. The magnitude of crowding was ~30% greater for monocular than dichoptic crowding at 0 SOA. Crowding’s unique time course rejects flash suppression, rivalry as well as metacontrast, pattern, and object substitution masking as explanations for the results. Our data suggest that crowding operates over a relatively broad temporal window and raise the intriguing possibility that there are independent monocular and binocular stages of crowding.