Radial Bias Alters Perceived Object Orientation
研究发现，视觉系统对径向朝向的刺激更敏感，并导致一种错觉：外周视野中物体的缺口朝向会被错误地感知为偏向径向轴。
Orientation sensitivity is a fundamental property of the visual system, but not all orientations are created equal. For instance, radially oriented stimuli, aligned with a line intersecting the center of gaze, produce greater activity throughout the visual cortex and are associated with greater perceptual sensitivity compared with other orientations. Here, we discuss a robust visual illusion that is likely related to this preference. Using a continuous response measure, participants ( N = 36 adults) indicated the gap position in a peripheral Landolt C placed in one of eight orientations and eight locations along four meridians (vertical, horizontal, 45°, 135°). The error distributions revealed that the perceived gap was attracted toward the radial axis. For instance, the gap in a regular C would often be wrongly perceived as tilted 45° corresponding to the oblique meridian where it was placed. These findings demonstrate an unsuspected early-vision influence on the perceived orientation of an object.