視知覚に於ける場の強さの測定

Abstract

Purpose-1) To measure the strength of the field-forces formed inside and outside a figure by estimating the stimulus threshold of a spot-light at different places inside and outside the figure. And2) to test the hypothesis of Köhler's electric theory of visual field.Procedures-Stimulus figures were cut out of a card board in the dark-room. They were then lighted by a light coming from the other side of a clouded-glass. A spot of light was thrown on the figure by a spot light apparatus in the adjoining room. Position and light strength of the spot could be changed freely by a resistance. A volt-meter was connected to make the measurement of lumen exactly. Dark-room was used. Dark-adaptation for 15 minutes before beginning the experiment.Stimulus threshold was measured at various places on the figure by gradually weakening the volt-meter and light from a point where the light spot could be seen clearly. Repeated each experiment 5 times. Subjects were 3. Observation distance 50cm.Results-1) The light stimulus threshold was weakened as the distance between the spot-light and the figure became greater. Consequently the strength of field forces (M) is in functional relationship with the distance (D) from the figure.2) Then, the light stimulus threshold was strengthened with the figure. Consequently M is in functional relationship with the clearness (H) of the figure.3) Other conditions being equal, the light stimulus threshold varies according to the nature of the figure. Therefore, M is affected by the particular figure structure.Theoretical Consideration-From above experimental facts M=f (D. H. E). can be inferred. Then upon seeking the functional relation of these based upon the experimental measurement value, the result on the outside of a figure was M=fEHd/DdM=Strength of field-forcesE=The figure particular structureH=Degree of clearness (Contrast of Figure and Ground)D=Psychological distance from the figureb & d=ConstantAnd under the conditions of these experiments in the dark-room b=-0.5 d=0.544Now, the field forces in physical Gestalt have been based decidedly on the experimental facts that they are proportional to the amount of electricity (y) and in inverse proportion to the distance squared (γ2). And, but, when we study the results of our experiments, that is, the strength of the psychological field forces measured by the light stimulus threshold, we find that the two are very much similar even in their functional relations. Consequently we may conclude that our results have fairly well proved the validity of the hypothesis of Kohler's electric theory in visual perception.