Sato Hiromi, Motoyoshi Isamu, Sato Takao
Department of Psychology, The University of Tokyo, Japan.
J Vis. 2012 Feb 3;12(2):3. doi: 10.1167/12.2.3.
The apparent contrast of a texture is reduced when surrounded by another texture with high contrast. This contrast-contrast phenomenon has been thought to be a result of spatial interactions between visual channels that encode contrast energy. In the present study, we show that contrast-contrast is selective to luminance polarity by using texture patterns composed of sparse elongated blobs. The apparent contrast of a texture of bright (dark) elements was substantially reduced only when it was surrounded by a texture of elements with the same polarity. This polarity specificity was not evident for textures with high element densities, which were similar to those used in previous studies, probably because such stimuli should inevitably activate both on- and off-type sensors. We also found that polarity-selective suppression decreased as the difference in orientation between the center and surround elements increased but remained for orthogonally oriented elements. These results suggest that the contrast-contrast illusion largely depends on spatial interactions between visual channels that are selective to on-off polarity and only weakly selective to orientation.
当一种纹理被另一种具有高对比度的纹理包围时，其明显的对比度会降低。这种对比-对比现象被认为是编码对比能量的视觉通道之间空间相互作用的结果。在本研究中，我们通过使用由稀疏细长斑点组成的纹理图案表明，对比-对比对亮度极性具有选择性。仅当明亮（黑暗）元素的纹理被具有相同极性的元素纹理包围时，其明显的对比度才会大幅降低。对于具有高元素密度的纹理，这种极性特异性并不明显，这些纹理与先前研究中使用的纹理相似，可能是因为此类刺激应不可避免地激活开型和关型传感器。我们还发现，随着中心和周围元素之间的方向差异增加，极性选择性抑制会降低，但对于正交方向的元素则仍然存在。这些结果表明，对比-对比错觉在很大程度上取决于对开-关极性具有选择性且仅对方向具有弱选择性的视觉通道之间的空间相互作用。
