圖形残效の研究 (第2報告)

Abstract

Purpose : This paper deals with the results of our experiments which were conducted to examine how the following three factors would determine the amount of figural after-effects. They were the length of the inspection time, the intensity of light stimulus comprising the inspection figure (I. F.) and the brightness of the field where the stimulus figures were presented.Method and Conditions : The distance between the subject and the fixation point was lm. The number of subjects was no less than 4 in any experiment. As soon as the inspection period had elapsed, the subject was asked to judge immediately which one of the two figures, the method of complete series. In the tables, plus sign indicates the increase in the apparent size or the overstimation of the standard T. F. and minus sign the shrinkage or the underestimation of it.All the experiments were performed in the dark room and the standard brightness of the field where the stimulus figures were presented was kept to be 1350 lux.Results :1. When the size of the I. F. was half as large as that on the standard T. F., The latter figure appeared expanded immediately after the inspection time, the amount of effect increased with the increase in the length of the inspection time.When the I. F. coincided completely with the standard T. F. or when the size of the I. F. was two times as large as that of the standard T. F., the standard T. F. appeared shrinked immediately after the inspection time and the amount of the effect also increased with the increase in the length of the inspection time. (See Table 1, A, and Fig. 1.)Concerning the factor of the inspection time upon the amount of figural after-effects, the above mentioned results were statistically significant when the method of analysis of variance was applied to these results. (See Table 1, B.)2. Changes in the intesity of the 1. F. by using the achromatic papers of different brightness did not cause any differnce in the amount of figural after-effects. (See Table 3, A. and B.)3. However, in the experiment in which the light stimulus was used, the amount of figural after-effects increase with the increase in the intensity of the I. F.This result was also statistically significant.(See Table 4, A and B and Fig. 2)4. Differences in the brightness of the field where the stimulus figures were presented did not case any change in the amount of figural after-effects. (See Table 5)