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| Volume 8, Number 3, Article 13, Pages 1-11 |
doi:10.1167/8.3.13 |
http://journalofvision.org/8/3/13/ |
ISSN 1534-7362 |
Dynamic distortion of visual position representation around moving objects
Katsumi Watanabe |
Research Center for Advanced Science & Technology, The University of Tokyo, Meguro-ku, Tokyo, National Institute of Advanced Industrial Science & Technology, Tsukuba, Ibaraki, Japan, & ERATO, Japan Science & Technology Agency, Atsugi, Kanagawa, Japan |
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Kenji Yokoi |
Research Center for Advanced Science and Technology, The University of Tokyo, Meguro-ku, Tokyo, Japan, & National Defense Academy of Japan, Yokosuka, Kanagawa, Japan |
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Abstract
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.
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