Study on Geometrical Illusions Under Various Stimulus-Presenting-Conditions.

本研究的目的是探讨不同几何错觉在以下两种刺激呈现条件下的特殊表现；(1)错觉（投射在屏幕上）以三种方向或三种频率振动，(2)典型的错觉（艾宾浩斯错觉）被许多受试者通过使用方便的“小册子”来观察，其中印有各种刺激呈现条件的错觉。结果如下：(1)在不同的刺激振动条件下，所有的观察者都报告了错觉幅度（MIs）的明显下降。这种MIs的减少表明振动（直接操纵）对幻觉的抑制作用。此外，我们还可以用“对直接操纵的敏感性”这一新的视点对错觉进行分类。(2)在“小册子呈现”下，艾宾浩斯错觉显示出与使用严格刺激呈现条件下的另一实验相似的倾向。此外，通过分析被试的反应，我们可以发现两种特殊的倾向（对比型和同化型）。在本研究中，将上述两种刺激呈现条件作为调节各种错觉产生的“控制器之一”。在进一步的研究中，我们正在检查刺激旋转下幻觉的表现。

The purpose of this study is to investigate the special appearances of the various geometrical illusions under the following two stimulus presenting conditions ; (1) the illusions (projected on a screen) are vibrated in three kinds of directions or three kinds of frequency, and (2) the typical illusion (Ebbinghaus) is observed by many subjects by using handy "booklet" in which illusions with various stimulus presenting conditions are printed.Results are as follows. (1) all observers reported the clear decrease of the magnitudes of illusion (MIs) in the various conditions of stimulus vibration. This decrease of the MIs indicated suppressive effects of the vibration (direct manipulation) on the illusions. Moreover, we could classifly the illusions with the new viewing point of "sensitivity for direct manipulation". (2) Under the "booklet presentation, Ebbinghaus illusions indicated similar tendencies to those obtained under another experiments by use of strict stimulus presenting conditions. In addition, we could find the special two kinds of tendencies (contrast-type and assimilation-type) by analyzing the responses of the subjects.In this study, the above two stimulus presenting conditions are regarded as "one of the controllers" to adjust the generation in various kinds of illusion. At a further study, we are examining the appearances of the illusions under the stimulus rotation.