This work demonstrates a lightness phenomenon useful to extend the notion of "belongingness," which is crucial to explain a class of illusions that include simultaneous lightness contrast, the Koffka-Benussi ring, the Benary cross, and the White effect. These phenomena manifest some kind of dissimilarity, difference, or change responsible for the perceived contrast. The dissimilarity is related to the "belongingness" of the crucial gray elements (i) to a unique or separated/divided object, as in the Koffka-Benussi ring, or (ii) to the figure or to the background, as in the Benary and White effects. If we plausibly assume that differences and changes are biologically important to be detected and if necessary highlighted, then any visible difference might induce a contrast effect. This is the main hypothesis demonstrated by the lightness phenomenon based on checks grouped vertically, split in two upper and lower halves, and segregated from the homogeneous gray background. The checks are alternated and vertically/horizontally reversed in the upper and lower halves of the pattern. Despite the constant visual organization and in spite of the identical local contrast within each check, the inner area of the elements of the upper group appears darker than the one of the lower group. The visible dissimilarity, although not related to the notion of belongingness, is sufficient to elicit a clear lightness difference.

中文翻译：

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关于亮度现象。

这项工作证明了亮度现象可用于扩展“归属感”的概念，这对于解释包括同时亮度对比，科夫卡-贝努西环，贝纳利十字架和怀特效应的一类幻觉至关重要。这些现象表明某种不同，差异或变化是造成感知对比度的原因。差异与关键灰色元素的“归属”有关（i）到唯一或分离/分开的对象，例如在Koffka-Benussi环中，或（ii）在图形或背景上，例如在Benary中和白色效果。如果我们合理地假设差异和变化在生物学上很重要，就必须加以检测，并在必要时加以强调，那么任何可见的差异都可能引起对比效果。这是主要的假设，它是由基于垂直分组，分成上下两半并与均匀的灰色背景隔离的支票的轻度现象证明的。在图案的上半部分和下半部分中，检查交替进行，并且垂直/水平反转。尽管视觉组织是恒定的，并且尽管每次检查中都具有相同的局部对比度，但是上组元素的内部区域似乎比下组元素的内部区域更暗。尽管与归属概念无关，可见的差异足以引起明显的亮度差异。在图案的上半部分和下半部分中，检查交替进行，并且垂直/水平反转。尽管视觉组织是恒定的，并且尽管每次检查中都具有相同的局部对比度，但是上组元素的内部区域似乎比下组元素的内部区域更暗。尽管与归属概念无关，可见的差异足以引起明显的亮度差异。在图案的上半部分和下半部分中，检查交替进行，并且垂直/水平反转。尽管视觉组织是恒定的，并且尽管每次检查中都具有相同的局部对比度，但是上组元素的内部区域似乎比下组元素的内部区域更暗。尽管与归属概念无关，可见的差异足以引起明显的亮度差异。