アイテム詳細

要旨

De Valois and De Valois [1] showed that moving Gabors (cosine gratings windowed by a stationary 2-dimensional Gaussian envelope) are locally misperceived in their direction of motion. In a pointing task, Yamagishi, Anderson and Ashida [2] reported even stronger visuo-motor localization error especially when participants had to make a speeded response. Here, we examined motion-induced bias in the context of an active navigation task, a situation in which perception and action are tightly coupled. Participants were presented with a birds-eye view of a vertically moving contour that simulated observer motion along a path. Observers centrally fixated while the path and a moving Gabor target were presented peripherally. The task was to follow the path with the moving Gabor, whose position (left/right) and direction(towards left/right) were varied in separate blocks. Gabor eccentricity was constant relative to fixation, with observers adjusting their simulated position with a joystick. Deviations from the path were analyzed as a function of Gabor direction. We found large and consistent misalignment in the direction of the moving Gabor, indicating that global position/motion judgments during action can be strongly affected by irrelevant local motion signals.