Abstract
Motion-Induced-Blindness (MIB) refers to the phenomenon in which perceptually salient targets, when superimposed on a global moving-dots pattern, disappear and reappear alternatively after prolonged viewing (Bonneh, Cooperman, & Sagi, 2001, Nature). Recently, New and Scholl (in press, Psychological Science) provide a functional account as to why MIB occurs. In their perceptual scotoma hypothesis, the disappearance of the target in MIB displays is attributed to the possibility that our visual system treats the target as being a perceptual scotoma in order to separate the invariant target from the distal surrounding changing background. Here we report counterexamples to argue against the perceptual scotoma account. First, we show that MIB occurs when the target and the background are both static, moving, or changing; naming, when the target is not invariant with respect to the background and thus an inference of scotoma of the visual system itself should not be made in the first place. Further, we show similar oscillation patterns of MIB and bi-stable figures such as Necker cube and the latter are by no means akin to any kind of perceptual scotoma. As the perceptual scotoma hypothesis cannot adequately explain these results, we suggest that MIB may be related to a more general mechanism of figural competition.
[Supported by the National Science Council of Taiwan, NSC 95-2413-H-039-002, 96-2413-H-039-001-MY2, 96-2752-H-002-008-PAE, and 96-2413-H-002-009-MY3].