Dynamic distortion of visual position representation around moving objects.
The relative visual positions of briefly flashed stimuli are systematically modified in the presence of motion signals (R. Nijhawan, 2002; D. Whitney, 2002). Previously, we investigated the two-dimensional distortion of relative-position representations between moving and flashed stimuli. The results showed that the perceived position of a flash is not uniformly displaced but shifted toward a single convergent point back along the trajectory of a moving object (K. Watanabe & K. Yokoi, 2006, 2007). In the present study, we examined the temporal dynamics of the anisotropic distortion of visual position representation. While observers fixated on a stationary cross, a black disk appeared, moved along a horizontal trajectory, and disappeared. A white dot was briefly flashed at various positions relative to the moving disk and at various timings relative to the motion onset/offset. The temporal emerging-waning pattern of anisotropic mislocalization indicated that position representation in the space ahead of a moving object differs qualitatively from that in the space behind it. Thus, anisotropic mislocalization cannot be explained by either a spatially or a temporally homogeneous process. Instead, visual position representation is anisotropically influenced by moving objects in both space and time.
Watanabe
Katsumi
K
Research Center for Advanced Science and Technology, The University of Tokyo, Meguro-ku, Tokyo, Japan. kw@fennel.rcast.u-tokyo.ac.jp
Yokoi
Kenji
K
D016880:Anisotropy; D005133:Eye Movements / Q000502:physiology*; D006801:Humans; D009039:Motion Perception / Q000502:physiology*; D009903:Optical Illusions; D010775:Photic Stimulation; D014795:Visual Pathways / Q000502:physiology