Abstract
"Perceptual disappearance" refers to a group of phenomena in which physically presented visual stimuli are perceived as invisible. This dissociation between the physical world and the perceptual experience suggests that visibility is not simply governed by object properties, but can be altered with changes in the internal states. Here we attempt to specify the information available on visual stimuli during perceptual disappearance by examining interactions between the visible and the perceptually invisible. Observers preformed the Motion Induced Blindness task (MIB; Bonneh, Cooperman, & Sagi, 2001), wherein a target (1.5ᵒ eccentricity) perceptually disappears when superimposed onto rotating background (10x10 ‘+’ patterns, 0.7ᵒ width, 1.4ᵒ spacing). A ‘Cue’ was presented next to the target upon observers’ report of perceptual disappearance. Target and cue were presented together for a limited interval (200, 300, 400ms) before the target was physically erased, permitting an estimation of the time required for perceptual reappearance. Observers were asked to report target reappearance. The presentation of a cue resulted in increased proportions of reappearances. Reappearances were relatively slow and required the target presence for 300-400ms since cue presentation. For a Gabor target (σ=0.12ᵒ, λ=0.17ᵒ, 100% contrast), the proportion of reappearances was higher with a collinear Gabor ‘Cue’ relative to an orthogonal cue (0.80 vs 0.37; spontaneous=0.53) and with a proximal cue (0.53ᵒ) relative to a more distant cue (1.2ᵒ) (0.77 vs 0.50; spontaneous=0.30). For an isosceles-triangle target (0.49ᵒ), reappearance rate increased in the presence of proximal triangular cues (0.8) relative to square or circular cues (0.5), irrespective of the triangular cue shape and size. This suggests dependence of reappearances on local features similarity between target and cue. Taken together our findings show preserved information about the location and features of the unaware target. This may imply that some visual processes sensitive to feature-similarity operate across the boundary of awareness.
Meeting abstract presented at VSS 2015