圖形殘效の數量的分析 (第1報告)

Abstract

Purpose The purpose of the present study is to determine figural after-effects (Köhler-effect) and Gibson's negative after-effects quantitatively as a function of the inspection time and of the time after inspection.Method The appratus is shown in Fig 1. Figures used in Exp. I, Exp. II and Exp. IV are shown in Fig. 2, Fig. 7 and Fig. 10 respectively. The general procedure was the same as Köhler's and Wirt's “Vollreihen Mothode” was used to measure the amount of after-effect. The course of the declination of after-effects. The course of the declination of after-effects was caught every five seconds by subjects' judgement. The length of the inspection period were 1, 5, 15, 30, 60, 120 and 240 sec.The test for the declining process of figural after-effects in Exp. III under the same arrangement of figures as Exp. I was performed by Hammers' second method which eliminated the factor of successive induction. Exp. V was the test-experiment performed under the condition shown in Eig. 13 which was considered to be the test situation of Exp. IV.Results 1) Under the same conditions of experiments, the Köhler-effect and the Gibson-effect were demonstrated to be identical process.2) The amount of after-effects (including Gibson's negativre after-effects) depends upon the size and arrangement of figures. If the size and arrangement of figures are kept constant, the amount of after-effects percieved immediately after the inspection of I. F. remains constant irrespective of the length of the inspection period.On the contrary as regards colour-effects, the longer the inspection time is, the more conspicuous are the effects.3) The amount of after-effects is maximum immediately after inspection, at first it diminishes quickly, then later gradually. When the inspection time is shorter, the gradient of the decay-curve is sharper. The decay-curves of after-effects strictly agree with Muller's formula.4) The so-called growth-curves of the after-effects that have been determined by Hammer etc. are shown to be nothing more than thecurve of after-effects considered as a function of the inspection time under the condition of several seconds after the inspection of I. F. Therefore, these curves reveal only the limited case of the growing process of after-effects.5) The gradient of the decay-curve of after-effects that in the decay-curve under the condition of the larger I. F. (see Fig. 2) is slower than that of the smaller I. F. (see Fig. 7). The longer the inspection time is, the more prominent is the defference of the gradient in decay-curves.6) Although in determining the decay-process of after-effects the method of successive judgement is a very convenient procedure as Hammer has pointed out, there is a significant difference between the results by the method of successive judgement (Hammer's first method) and those by the method of white-paper-insertion (Hammer's second method) in our experiments. In order to get the correct data, it is neccessry to modify the data obtained by the method of successive judgement.7) Gibson-effects are influensed more or less by the direction of the curved-line. This fact may be explained by the factor of “Zentrishe Schrumpfung des Sehraumes” (Obonai's theory) and by the factor of the potential-illusion in comparative judgement of parallel curved-line (V. F. and T. F.)8) In experiment on figural after-effects, especially in studying temporal factors, we must take into consideration the judgement mechanism of the subjects.