感電性を指標とする誘導過程の研究 (3)

凝視点の移動を伴う実験 (2)

抄録

In an earlier report (3), the authors have provided experimental evidence that, under certain circumstances, the configuration of the induction takes its form in accordance with what a subject perceives in the visual field. If the pre-illuminating patterns I, II, III and a point in IV of Fig. 1 are presented in succession and fixation is shifted from the left mark to the right one between the presentation of III and that of IV, the indirect induction of Y (yellow) in I is observed at the points 1 and 4 etc. in IV and the neutralization, i.e., the arrival of the induction initiated by B (blue) in II is demonstrated at the point 2 (the pattern P in Fig. 2). Let us consider the moment when IV is presented. The region of the retina that is pre-illuminated by I, II and III, if projected to the plane where the pre-illuminating patterns are presented, is given by the dotted figure in Fig. 2, whereas the full lined figure indicates the place where I, II and III are presented, i.e., where these patterns are perceived in the visual field. Hence, the only possible interpretation may be as follows. In so far as I, II, III and IV are presented, the configuration of the induction does not exist around the pre-illuminated region of the retina, but it does take its form around the region in the visual field where the pre-illuminating patterns are perceived. This is what we named the P-result and the discovery was so unexpected that the need of its confirmation from every possible angle was pressing.
In a series of experiments described in this article, the pre-illuminating patterns, the shift of fixation, the delivery of the electrical pulse to the eye, the definition of the induction (contrast effect, CE) etc. were exactly the same as those employed in the previous experiments (3). However, the psychophysical method to obtain the electrical threshold for evoking the phosphene was changed. Namely, in place of the method of limits in the descending series, the one in the ascending series was employed in Experiment 3 (Fig. 3), and the constant method in Experiment 4 (Fig. 6). And it became clear, irrespective of the method, the P-result was always obtained under the conditions mentioned above. In passing, the goodness of fit of the φ(γ) function to the data in the case of the constant method was satisfactory as shown in Fig. 4 and in Fig. 5.
So far, the interval of time between the cessation of IV and the delivery of the electrical pulse was fixed at 1.5sec. since only existence or non-existence of the induction of Y was at issue. In Experiment 5, however, the interval was changed from 1 to 3sec. for the purpose of obtaining the so-called ζ-time curve. The P-result was also ascertained because two distinctively different types of curves appeared as shown in Fig. 7. The one (at the points 1 and 4) is of typical type for existence of the induction and the other (at the point 2) for occurrence of the neutralization.