A scaling analysis of the snake lightness illusion
A scaling analysis of the snake lightness illusion
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DOI：
10.3758/pp.70.5.828
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发表时间：
2008-07-01
期刊：
影响因子：
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通讯作者：
Maloney, Laurence T.
中科院分区：
文献类型：
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作者：
Logvinenko, Alexander D.;Petrini, Kartn;Maloney, Laurence T.
Logvinenko和Maloney（2006）测量了放置在两个场景中的非彩色表面之间的感知差异，这些场景由强度不同的中性光照明。使用一种新的缩放方法，他们发现光表面对之间的差异可以表示为两个维度的加权线性组合，“表面亮度”（表面亮度对数差异的感知相关性）和“表面亮度”（对应于场景中光强度的对数差异）。在这里，我们试图衡量这些方面的贡献，一个令人信服的亮度错觉（“蛇错觉”）。通常认为这种错觉是由于错误地将蛇图案分割成不均匀照明的区域。我们发现，蛇图案的错觉移位发生沿着表面亮度维度，没有从表面亮度的贡献。因此，即使确实发生了将蛇图案错误地分割成不均匀照明的条带的情况，它也会自相矛盾地显示出表面亮度的虚幻变化，而不是表面亮度。我们推测，错觉强度取决于两组照明线索之间的平衡，信号的真实（均匀）照明和图片（不均匀）照明。
Logvinenko and Maloney (2006) measured perceived dissimilarities between achromatic surfaces placed in two scenes illuminated by neutral lights that could differ in intensity. Using a novel scaling method, they found that dissimilarities between light surface pairs could be represented as a weighted linear combination of two dimensions, "surface lightness" (a perceptual correlate of the difference in the logarithm of surface albedo) and "surface brightness" (which corresponded to the differences of the logarithms of light intensity across the scenes). Here we attempt to measure the contributions of these dimensions to a compelling lightness illusion (the "snake illusion"). It is commonly assumed that this illusion is a result of erroneous segmentation of the snake pattern into regions of unequal illumination. We find that the illusory shift in the snake pattern occurs along the surface lightness dimension, with no contribution from surface brightness. Thus, even if an erroneous segmentation of the snake pattern into strips of unequal illumination does happen, it reveals itself, paradoxically, as illusory changes in surface lightness rather than as surface brightness. We conjecture that the illusion strength depends on the balance between two groups of illumination cues signaling the true (uniform) illumination and the pictorial (uneven) illumination.