視野鬪爭に及ぼす先行條件の効果 (II)

抄録

In the experiments previously reported, we found that, in binocular rivalry of two antagonistic figures, the preceding stimulation of one or both eyes by one figure had an effect which made the other figure dominant in succeeding rivalry. And we concluded that this after effect was due, in the main, to the figurality per se of the preceding stimulus.
It remains to examine more closely the factors influencing our results, in order to make any theoretical assertion based on them. But at present we can only describe some facts we have found in the supplemen tary experiments, as to the timporal course of the e effect, the effect of voluntary control of the rivalry, and the effect of figurality other than on ealready mentioned.
1. The relation between the duration of the preceding stimulation and its after-effect was examined, following the same procedure as in experiment 1 in the previous report. The duration of the preceding stimulation was varied from 15 to 120 seconds every 15 seconds (In the original experiment this was 90 or 120 seconds.)
Fourr observers participated.
In general no linear relationship was found to exist, but in some cases even 15 seconds' duration of preceding stimulation showed remarkable effect and made the antagonistic figure dominant in succeeding rivalry.
2. With four observers the after-effect was assured to endure at least 5 or 6 minutes, by continuous observation of rivalry for about 15 minutes directly following the termination of preceding stimulation of 120 seconds.
The effect could last not so long when the observation was not continuous.
3. Two figures as before were presented one to each eye, and one of them was voluntarily controlled to dominate the other for 120 seconds, and then the ordinary observation of rivalry for 60 seconds fallowed. In this case, the effect of the preceeing dominancy of one figure was not present.
4. Two figures were alternately presented one to each eye, and the time one figure was exposed was longer than the other. Only one observer was employed. He showed the tendency that the longer the duration of the one the greater the dominancy of the other in the succeding rivalry.
5. In our experiments, the stimuli had hitherto been [
L_??_·R_??_] the left eye being stimulated with _??_, the right eye with _??_, in reality, five oblique lines in a light patch. Now, one observer was tested by some different types of figures. In those cases also the same effect as before was significant. Further, the situation of binoculer colour rivalry was examined, and the result was not contradictory to our previous findings.
6. Instead of binocular rivalry, observation of reversibie figure was resorted to. Here again the similar effect was found, though not so clear enough as in that of the rivalry.
Some observations were obtained that these effects of the preceding stimulation may not only be a matter of retinal change, e.g. retinal adaptation or fatigue, but also and essentially of dynamical reconstruction or reorganization of structure in the higher system.