Webster M A, Mollon J D
Department of Experimental Psychology, University of Cambridge, England.
Vision Res. 1994 Aug;34(15):1993-2020. doi: 10.1016/0042-6989(94)90028-0.
Most models of color vision assume that signals from the three classes of cone receptor are recoded into only three independent post-receptoral channels: one that encodes luminance and two that encode color. Stimuli that are equated for their effects on two of the channels should be discriminable only to the remaining channel, and are thus assumed to isolate the responses of single channels. We used an asymmetric matching task to examine whether such models can account for changes in color appearance following adaptation to contrast--to temporal variations in luminance and chromaticity around a fixed mean luminance and chromaticity. The experiments extend to suprathreshold color appearance the threshold adaptation paradigm of Krauskopf, Williams and Heeley [(1982) Vision Research, 32, 1123-1131]. Adaptation changes the perceived color of chromatic test stimuli both by reducing their saturation (contrast) and by changing their hue (direction within the equiluminant plane). The saturation losses are largest for test stimuli that lie along the chromatic axis defining the adapting modulation, while the hue changes are rotations away from the adapting direction and toward an orthogonal direction within the S and L-M plane. Similar selective changes in both perceived color and perceived lightness occur following adaptation to stimuli that covary in luminance and chromaticity. The selectivity of the aftereffects for multiple directions within color-luminance space is inconsistent with sensitivity changes in only three independent channels. These aftereffects suggest instead that color appearance depends on channels that can be selectively tuned to any color-luminance direction, and that there are no directions that invariably isolate responses in only a single channel. We use the perceived color changes to examine the spectral sensitivities of the chromatic channels and to estimate the distribution of channels. We also examine how adaptation alters the contrast-response function, how it affects reaction times for luminance and chromatic contrast, the extent to which the aftereffects exhibit interocular transfer, and the way in which the perceived color changes differ from those induced by conventional light adaptation.
大多数色觉模型假定，来自三类视锥感受器的信号仅被重新编码为三个独立的感受器后通道：一个编码亮度，另外两个编码颜色。对其中两个通道产生相同效应的刺激，应该只能通过剩余的通道来区分，因此被认为可以分离单个通道的反应。我们使用了一项非对称匹配任务，来检验此类模型是否能够解释适应对比度后颜色外观的变化——适应围绕固定平均亮度和色度的亮度和色度的时间变化。这些实验将克劳斯科普夫、威廉姆斯和希利[（1982年）《视觉研究》，32卷，1123 - 1131页]的阈值适应范式扩展到了超阈值颜色外观。适应通过降低测试色刺激的饱和度（对比度）以及改变其色调（等亮度平面内的方向）来改变其感知颜色。对于沿着定义适应调制的色轴的测试刺激，饱和度损失最大，而色调变化是在S和L - M平面内从适应方向旋转到正交方向。在适应亮度和色度共同变化的刺激后，感知颜色和感知明度也会出现类似的选择性变化。颜色 - 亮度空间内多个方向的后效选择性与仅三个独立通道中的敏感度变化不一致。相反，这些后效表明颜色外观取决于可以选择性地调谐到任何颜色 - 亮度方向的通道，并且不存在始终仅分离单个通道反应的方向。我们利用感知颜色变化来检验颜色通道的光谱敏感度，并估计通道的分布。我们还研究了适应如何改变对比度 - 反应函数，它如何影响亮度和颜色对比度的反应时间，后效表现出双眼间转移的程度，以及感知颜色变化与传统光适应引起的变化的不同方式。
