Cropper Simon J
Department of Psychology, University of Melbourne, Vic., Australia.
Vision Res. 2006 Mar;46(5):724-38. doi: 10.1016/j.visres.2005.06.034. Epub 2005 Aug 19.
This study seeks to clarify the reasons for some of the differences in the published data on chromatic motion perception, and to provide further support for the existence of a low-level motion mechanism sensitive to purely chromatic change. Observers discriminated the direction of motion of displaced sinusoidal gratings in the presence of a static grating mask (or pedestal). Each component of the stimulus was independently described in cardinal colour space and calibrated for subjective equiluminance using multiple methods. The motion structure, stimulus size, temporal frequency, contrast, relative phase and chromatic properties were all varied parametrically and the data cast in terms of predictions made by two different theoretical approaches to the test-mask combination. The vast majority of the data were well explained by a low-level motion mechanism sensitive to the motion of foveally-placed chromatic stimuli. Data consistent with either higher-level motion perception or a luminance-like signal were found outside the fovea and when the stimulus properties did not otherwise favour chromatic motion perception. There was some explanation of inconsistencies in previously published data and a strong suggestion that previous results showing pedestal-like behaviour for these stimulus combinations were a special case rather than a general result.
本研究旨在阐明已发表的关于色觉运动感知数据中某些差异的原因，并为存在对纯颜色变化敏感的低水平运动机制提供进一步支持。观察者在存在静态光栅掩模（或基座）的情况下辨别位移正弦光栅的运动方向。刺激的每个成分在主色空间中独立描述，并使用多种方法针对主观等亮度进行校准。运动结构、刺激大小、时间频率、对比度、相对相位和颜色特性均进行参数变化，并根据两种不同的理论方法对测试掩模组合所做的预测来分析数据。绝大多数数据可以通过对中央凹放置的颜色刺激运动敏感的低水平运动机制得到很好的解释。在中央凹之外以及当刺激特性不支持颜色运动感知时，发现了与更高水平运动感知或类似亮度信号一致的数据。对先前发表数据中的不一致之处有一些解释，并且有力地表明，先前显示这些刺激组合具有类似基座行为的结果是一个特殊情况，而非普遍结果。
