Vergeer Mark, van Lier Rob
Donders Institute for Brain, Cognition and Behaviour, Centre for Cognition, Radboud University Nijmegen, P.O. Box 9104, 6500 HE Nijmegen, The Netherlands.
Perception. 2010;39(12):1565-78. doi: 10.1068/p6539.
Homogeneously coloured bars may exhibit lightness differences at the intersections. A well-known example is the Hermann grid illusion, where crossing white bars on a black background show dark patches at the crossings. Jung (1973, Handbook of Sensory Physiology volume VII/3, pp 1-152) found that the dark patches persist when thin outlines are drawn at the intersections, and are even visible in foveal vision. Recently, it has been shown that making distortions to the contours of a Hermann grid-like configuration results in the disappearance of the illusory dark spots (Geier et al, 2008 Perception 37 651 665). We show that thin outlines at the crossings of the distorted Hermann grid induce lightness differences in the same direction as in the original Hermann grid illusion, even in foveal vision and in displays consisting of two crossing bars. Our experiments reveal that the induced lightness differences are independent of the luminance polarity and shape of the contours at the intersection. We suggest that the effect results from lateral inhibition and an additional spreading and capturing of these differences between luminance contours. A similar capturing between collinear contours may play a role in peripheral vision in the original Hermann grid.
颜色均匀的条纹在交叉处可能会呈现出明度差异。一个著名的例子是赫尔曼网格错觉，即在黑色背景上交叉的白色条纹在交叉处会显示出暗斑。荣格（1973年，《感觉生理学手册》第七卷/3，第1 - 152页）发现，当在交叉处绘制细轮廓时，暗斑依然存在，甚至在中央凹视觉中也可见。最近的研究表明，对类似赫尔曼网格的构型轮廓进行扭曲会导致虚幻暗斑消失（盖尔等人，2008年，《感知》37卷，651 - 665页）。我们发现，在扭曲的赫尔曼网格交叉处的细轮廓会像在原始赫尔曼网格错觉中一样，在相同方向上诱发明度差异，即使在中央凹视觉以及由两条交叉条纹组成的显示中也是如此。我们的实验表明，诱发的明度差异与交叉处轮廓的亮度极性和形状无关。我们认为，这种效应是由侧向抑制以及亮度轮廓之间这些差异的额外扩散和捕捉导致的。在原始赫尔曼网格的周边视觉中，共线轮廓之间类似的捕捉可能也起作用。
