Abstract
Various studies show that visual stimuli that are not consciously accessible may retain their properties. Here we explored the interaction between such stimuli and stimuli that are consciously available. We used the phenomenon of Motion-induced-blindness (MIB; Bonneh et. al., Nature 2001) in which a salient static or slowly moving pattern (target) may disappear and reappear spontaneously in the presence of a global moving pattern (mask). Here we used a transient cue to induce reappearance (Kawabe et al., Conscious Cogn. 2006). In the experiments, a small target patch located at a fixed location (2 deg of eccentricity, usually in the upper left quadrant) was made invisible via a global moving rotating grid mask. Shortly after disappearance reported by the Os (100 ms), another small patch (cue) was briefly flashed (100 ms) and the whole trial was terminated after 200–800 ms by erasing both target and mask. The cue, which was clearly seen, often caused the reappearance of the invisible target within the limited trial time. Os reported target reappearance. In the first experiment, the target was a small (0.4 deg) bright patch and the cue was identical patch presented at different locations. We found that the amount of induced reappearance of the target depended on the target to cue separation and on the time window, with more reappearance for proximal cues and longer time windows. In the second experiment, we used a Gabor target and a Gabor cue of different orientations, distance and layout (collinear or orthogonal). We found higher reappearance rate for similar orientations, collinear configurations and proximal locations. The results show that invisible stimuli keep their location and orientation tags and demonstrates that grouping processes sensitive to proximity and similarity operate across the boundary of awareness.
Supported by grants from the National Institute for Psychobiology in Israel