Abstract
In motion-induced blindness (MIB), salient target objects will fluctuate into and out of conscious awareness when superimposed onto certain global moving patterns. Previous studies have delimited several factors that mediate MIB, but there is little consensus on why it occurs at all. Here we explore a new possibility: MIB occurs due to the visual system's attempt to separate distal stimuli from artifacts of damage to the visual system itself. When a small target object is invariant with respect to changes that are occurring to large regions of the surrounding visual field, the visual system may discount that stimulus as akin a scotoma, and may thus fill it in. We discuss how this theory can account for many previous MIB results, and then describe and demonstrate several new effects that support this idea. Three examples: (1) Motion itself is not required: similar effects are obtained from other manipulations, such as cyclic global changes to the luminance of a static global pattern. (2) MIB is stronger with monocular vs. binocular viewing of the target, when the global motion pattern is always binocular. (3) MIB is vastly stronger when both the target and fixation point move together, compared to when they move relative to each other (e.g. in opposite directions). These and other results are all consistent with the hypothesis that the visual system treats the target object as an artifact or insult to its own structure and processing, rather than as an object in the external world. This new account is considerably different than previous accounts of MIB, but helps to connect it with other types of visual phenomena. In the end, ‘motion-induced blindness’ may be better described as just a special case of ‘perceptual scotomas’.