Nemati Farshad
Canadian Centre for Behavioural Neuroscience, Department of Neuroscience, University of Lethbridge, Lethbridge, Alberta, Canada T1K 3M4.
Perception. 2009;38(11):1585-600. doi: 10.1068/p6450.
Over the past few decades, different theories have been advanced to explain geometric-optical illusions based on various perceptual processes such as assimilation and/or contrast. Consistent with the contradictory effects of assimilation and contrast, Pressey's assimilation theory provided an explanation for the Müller-Lyer illusion, but failed to account for the Titchener (Ebbinghaus) illusion. A model that explains both Müller-Lyer and Titchener illusions according to a common underlying process may outline a unified explanation for a variety of geometric-optical illusions. In order to develop such a model, the concept of empty space is introduced as an area of the illusory figure that is not filled by line drawings. It was predicted that the magnitude of illusion would increase with the area of the empty space around the illusory figures. The effect of empty space on the magnitude of perceptual distortion was measured in Müller-Lyer figures, with outward arrowheads of different length. The results indicated an overestimation of the target stimulus in all of the figures. Nevertheless, consistent with the prediction of the present model, the horizontal line in the Müller-Lyer figure with the longest arrowheads appeared shorter than that with the shortest arrowheads, although the size contrast of these figures was the same. According to the analysis proposed in the present study, the area of empty space not only affects the magnitude of illusion but also serves as a contextual cue for the perceptual system to determine the direction of illusion (orientation). The functional relationships between the size contrast and empty space provide a common explanation for the Müller-Lyer, Titchener, and a variety of other geometric-optical illusions.
在过去几十年里，人们提出了不同的理论来解释基于同化和/或对比等各种感知过程的几何光学错觉。与同化和对比的矛盾效应一致，普雷西的同化理论解释了缪勒-莱尔错觉，但无法解释铁钦纳（埃宾豪斯）错觉。一个根据共同的潜在过程解释缪勒-莱尔错觉和铁钦纳错觉的模型，可能会为各种几何光学错觉勾勒出一个统一的解释。为了建立这样一个模型，引入了“空白空间”的概念，将其作为错觉图形中未被线条图填充的区域。据预测，错觉的程度会随着错觉图形周围空白空间的面积增加而增大。在带有不同长度向外箭头的缪勒-莱尔图形中，测量了空白空间对错觉程度的影响。结果表明，所有图形中的目标刺激都被高估了。然而，与本模型的预测一致，箭头最长的缪勒-莱尔图形中的水平线看起来比箭头最短的图形中的水平线短，尽管这些图形的大小对比是相同的。根据本研究提出的分析，空白空间的面积不仅影响错觉的程度，还作为一种背景线索，供感知系统确定错觉的方向（取向）。大小对比和空白空间之间的功能关系，为缪勒-莱尔错觉、铁钦纳错觉以及其他各种几何光学错觉提供了一个共同的解释。
