Appearances and Disappearances: Motion Induced Blindness Meets Binocular Rivalry

Motion-induced blindness (MIB) and binocular rivalry (BR) are examples of multistable phenomena in which our perception varies despite constant retinal input. It has been suggested that both phenomena relate to visual awareness and share a common underlying mechanism. We tried to determine whether experimental manipulations of the target dot and the mask systematically affect MIB and BR in a novel experimental paradigm that can elicit both phenomena. Participants reported perceived colour (isoluminant Red/Green) and disappearance of the target dot superimposed on a distracter mask (drifting sinewave grating or rotating array of blue crosses) by pressing and releasing corresponding keys. Our results suggest that MIB and BR were both affected by motion, but not by rivalry in the mask. Normalized disappearance was significantly increased for smaller targets, as well as monoptically presented targets but differently for the two types of masks. On the other hand contrast of dichoptic target dots in the left and right eye had a significant effect on duration, as well as number of appearances of the Red/Green target, but not on target disappearance. In summary, our results suggest dissociation between MIB and BR in hierarchical processing stages.