Arnold Derek H, Johnston Alan
Department of Psychology and Institute of Cognitive Neuroscience, University College London, Gower Street, London WC1E 6BT, UK.
Nature. 2003 Sep 11;425(6954):181-4. doi: 10.1038/nature01955.
Borders defined by small changes in brightness (luminance contrast) or by differences in colour (chromatic contrast) appear to move more slowly than those defined by strong luminance contrast. As spatial coding is influenced by motion, if placed in close proximity, the different types of moving border might appear to drift apart. Using this configuration, we show here that observers instead report a clear illusory spatial jitter of the low-luminance-contrast boundary. This visible interaction between motion and spatial-position coding occurred at a characteristic rate (approximately 22.3 Hz), although the stimulus motion was continuous and invariant. The jitter rate did not vary with the speed of movement. The jitter was not due to small involuntary movements of the eyes, because it only occurred at a specific point within the stimulus, the low-luminance-contrast boundary. These findings show that the human visual system contains a neural mechanism that periodically resolves the spatial conflict created by adjacent moving borders that have the same physical but different perceptual speeds.
由亮度的微小变化（亮度对比度）或颜色差异（颜色对比度）定义的边界似乎比由强烈亮度对比度定义的边界移动得更慢。由于空间编码受运动影响，如果将不同类型的移动边界放置得很近，它们可能会看起来相互分离。利用这种配置，我们在此表明，观察者反而报告低亮度对比度边界存在明显的虚幻空间抖动。尽管刺激运动是连续且不变的，但运动与空间位置编码之间的这种可见相互作用以特定速率（约22.3赫兹）发生。抖动速率不随运动速度变化。这种抖动不是由于眼睛的微小非自主运动，因为它仅发生在刺激内的特定点，即低亮度对比度边界处。这些发现表明，人类视觉系统包含一种神经机制，该机制会周期性地解决由具有相同物理速度但不同感知速度的相邻移动边界所产生的空间冲突。
