Motion-induced blindness in normal observers

Cases in which salient visual stimuli do not register consciously are known to occur in special conditions, such as the presentation of dissimilar sti muli to the two eyes(1) or when images are stabilized on the retina(2). Her e, we report a striking phenomenon of 'visual disappearance' observed with normal-sighted observers under natural conditions. When a global moving pat tern is superimposed on high-contrast stationary or slowly moving stimuli, the latter disappear and reappear alternately for periods of several second s. We show that this motion-induced blindness (MIB) phenomenon is unlikely to reflect retinal suppression, sensory masking or adaptation. The phenomen ology observed includes perceptual grouping effects, object rivalry and vis ual field anisotropy. This is very similar to that found in other types of visual disappearance, as well as in clinical cases of attention deficits, i n which partial invisibility might occur despite the primary visual areas b eing intact(3). Disappearance might reflect a disruption of attentional pro cessing, which shifts the system into a winner-takes-all mode, uncovering t he dynamics of competition between object representations within the human visual system.