Displacement in Figural After Effects and Simultaneous Illusions

Abstract

For the purpose of studying the field of the figure in visual perception, the displacement in Figural after-effects and Simultaneous-illusions was studied experimentally. The effect was measured quantitatively. That is, the amount and the direction of displacement were measured, presenting the dots inside or outside of the square successively in one case and simultaneously in the other case.
In part I, we dealt with the displacement in Figural after-effects, and bound he difference in the effect between the solid figure and the contour figure. The results may be summarized as follows :
1. With respect to the direction of displacement, a similar tendency was found generally in both figural situations.
2. As the Köhler's principle predicted, the amount of the displacement of the dots depended on the distance from the square, that is, it increased rapidly at first, reached the maximum, and then decreased gradually, according as the distance increased. The incremental and decremental curves were similar in form in both situations.
3. When the dots were presented outside of the square, the amount of the displacement in the case of the solid square was greater than that in the case of the contour figure, but this relation was reversed when they were presented inside of the square.
In part II, the displacement was measured in both cases of Figural after-effects and Simultaneous-illusions under the same figural conditions. The results were as follows :
1. In Figural after-effects, the direction of displacement was opposite, in general, to that in simultaneous-illusions, but in a few places outslide the square, it was found that the direction was similar in both situations.
2. The maximum amount of the displacement in Figural after-effects was at the remoter point from the square than in Simultaneous-illusions. So, the curves showing the relation between the amount of displacement and the distance from the square in the two situations were not symmetrical to each other with regard to the abscissa.
3. It could be said generally, that the amount of displacement in Figural after-effects was greater than in Simultaneous-illusions.
In these experiments we ascertained that the results did not always correspond to the Köhler's principle of displacement, but the so-called distance-paradox phenomenon existed distinctly in all occasions.