Object-based anisotropies in the flash-lag effect.
The relative visual position of a briefly flashed stimulus is systematically modified in the presence of motion signals. We investigated the two-dimensional distortion of the positional representation of a flash relative to a moving stimulus. Analysis of the spatial pattern of mislocalization revealed that the perceived position of a flash was not uniformly displaced, but instead shifted toward a single point of convergence that followed the moving object from behind at a fixed distance. Although the absolute magnitude of mislocalization increased with motion speed, the convergence point remained unaffected. The motion modified the perceived position of a flash, but had little influence on the perceived shape of a spatially extended flash stimulus. These results demonstrate that motion anisotropically distorts positional representation after the shapes of objects are represented. Furthermore, the results imply that the flash-lag effect may be considered a special case of two-dimensional anisotropic distortion.
Watanabe
Katsumi
K
Research Center for Advanced Science and Technology, The University of Tokyo, Tokyo, Japan. kw@fennel.rcast.u-tokyo.ac.jp
Yokoi
Kenji
K
D000328:Adult; D016880:Anisotropy; D005403:Fixation, Ocular; D006801:Humans; D009039:Motion Perception; D010364:Pattern Recognition, Visual; D011930:Reaction Time; D013028:Space Perception; D014796:Visual Perception