In the present study was investigated whether or not changes in spontaneous skin potential response (SPR) during sleep could be used as an indicator of psychophysiological activity. During the natural nocturnal sleep over 3 consecutive nights, 15 males entirely inexperienced in this type of experiment were observed with respect to the laboratory adaptation in terms of objective measures of EEG as well as of subjective measures using the rating-scale method and the questionnaire method. In addition changes in spontaneous SPR on the finger and on the dorsal hand were investigated during the adaptation process due to the laboratory effect. The following summary is based on the comparisons between the first and the third night results. 1. From the EEG profile, shortened latencies of sleep onset (stage 1), and of para-sleep, decreased relative duration of stage 1 and 2, and an increase duration of stage 4 were observed, and the findings confirmed the laboratory adaptation phenomenon (Table 1 & 2). 2. The subjective evaluation immediately after awakening revealed: i) disappearance of difficulty in falling asleep, ii) improvement in the feeling of a sound sleep and refreshed feeling after awakening, and iii) disappearance of the tendency of overestimating sleep latency. These results confirmed those in terms of the objective measures (Fig. 1 & 2). 3. The SPR frequency during allnight sleep decreased both on the finger and on the dorsal hand, and this decrease was more evident in the latter half of sleep (Fig. 3). 4. The SPR decreased in the stages of low amplitude EEG, i.e., stage 1, 2 and para-sleep, and no such decrease was observed in stage 4 (Fig. 4). 5. The correlation between the EEG stages and the SPR frequency on the finger and the dorsal hand was the lowest during the first night, but it increased later. The correlation between the EEG measure and the SPR frequency was higher when the latter was measured on the dorsal hand than when on the finger (Table 4). 6. Comparison of the changes of the SPR between finger and dorsal hand revealed a larger decrease for finger in stages 1, 2 and para-sleep which showed adaptation (Fig. 5). 7. The proportion of the period of para-sleep accompanied by SPR-bursts to the total para-sleep decreased (Fig. 6). 8. The spontaneous SPR during sleep has been explained as the release of cortical inhibitory center. However, the authors intended to revise this theory by proving the co-existence of psychophysiological mechanism, and the relationship between the activity of cortical inhibitory mechanism and that of the psychophysiological mechanism was discussed.
In our former report, we showed that the ways in which one judged the number of objects instantaneously varied with his age. Only a normal adult can select and use one of those ways spontaneously according to situations. Our studies here reported were designed to compare time values required for the instantaneous judging of the number of objects, when each one of various ways was forced on adults by instructions. Stimulus objects: Sixty-two kinds of cards were used. Each white card contained vertical black lines (of 1cm in length and of 0.5mm in width) which varied in numbers (one to ten) and in amounts of interval (two or three kinds). They were arranged either equidistantly (Exp. I) or articulated into some subgroups, each of which contained three or less lines (Exp. II). Subjects and Procedures: Four or five adults were given three or four kinds of instructions, that is, i) to count lines one by one, ii) by twos, iii) by threes and iv) in one's best way, whose usual features appeared in dividing lines into some subgroups spontaneously and utilizing some arithmetical operations on them. In addition, the subjects were instructed to judge as correctly and speedily as possible. We measured each time value required for the instantaneous judging of the number of lines contained on each card. Results and Conclusions: The time value varied according to instructions. The maximum was for judging under instruction i), the next under ii) or iii) and the minimum under iv). That order in which the time values diminish is supposed to correspond to the genetic order which was revealed in the ways used by children on the same work. But such differences of time values seem to depend upon the number of lines or that of subgroups. That is, the difference between the time value in the first way in the genetic order and that in the last way was not significant, when, the number of lines was one to three. Similarily the difference between the time value in the second way and that in the last way was not significant, when the number of subgroups was one to three. The amount of interval between lines had no effect on counting lines one by one, but some on counting work in such a way as to divide them into subgroups spontaneously. From these results we could conclude that, regardless of the differences in the forced instructions, the common operations for the judging of the number of objects were adopted by adult subjects, who the number of objects or that of subgroups was within “three” that is, the so-called first range of attention (cf. Fujii, 1966). But the different operations functioned according to the inspective forced instructions, when the number of objects or that of subgroups was over such a range.
The response in the center of the human fovea changes from On-type to Off-type as the inducing figure approachtes the fovea (this Journal, 1967, 38, 1-13). This findings could explain why the sensitivity measured in terms of light threshold decreases while that of CFF increases as the inducing figure approaches the test figure. On the basis of the results the present writer proposed a hypothesis that light sensitivity possesses two aspects of τ and κ. Furthermore, the following four methods have been devised to prove the hypothesis experimentally. Vibrating method 1. When a geometrical illusion figure is adequately vibrated in the direction of the appearance of illusion, the amount of illusion increases. Vibrating method 2. When grating lines are adequately vibrated in the face of a geometrical figure, they are deformed according to the characteristic of the figure. Vibrating method 3. When a small circle is adequately vibrated in the face of a geometrical figure, it is deformed from a circle to an ellipse. Flickering method. When one of two figures in the midst of binocular rivalry is flickered, the other is often disappeared immediately after the appearance of the flickering figure. The flickering method was designed to measure its flickering effect on the disappearance of the continuous figure. The present study is related to Vibrating method 2. First some experiments were conducted to test whether or not the deformation of the grating lines depends mainly upon the characteristic of figure on the following various conditions; (1) binocular vision and monocular vision, (2) illuminance of figure, (3) observing distance, (4) distance between grating lines and figure, (5) length of grating lines, (6) conditions of vibrations of grating lines, (7) observing time, (8) fixation point, (9) white-black relations between grating lines and figure, (10) number of grating lines, and (11) width of grating lines. Then some experiments were conducted to examine the relationship between the deformations of the grating lines and the following geometrical illusions; (1) Müller-Lyer, (2) Ponzo, (3) Zöllner, (4) Hering, (5) Wundt, (6) Höfler, (7) Pisco, and so on. The results obtained are shown in Figs. 3-6.
Recently, it is reported that (Sato, 1968a, b) at low range of flicker, apparent brightness enhances and observer's response variability increases as brightness enhances. These phenomena greatly depend on the relationship between stimulus frequency and temporal characteristics of neural activity, (e.g. refractory period, temporal summation) in visual system. According to observer's introspection, response variability is difficult to control voluntarily. This investigation was carried out in order to confirm the following hypothesis. Hypothesis: At low range of flicker, apparent brightness and observer's response variability increase as brighthess enhances. Underlying mechanism of these phenomena is the principle of optimum efficiency of neural activity in relation to stimulus and neural response intensity, and this principle works only through the mediation of the factor of temporal configuration of stimuli. Therefore, as far as the stimulus is flicker, similar results will obtained if observers were given some other task than brightnessmatching. Exp. 1: Increment thresholds of flicker target (4, 6, 8, 12.5, 19, 26, 35, 46 cps, diameter 1°) on background field (6°, 38.88mL, steady light) were measured. Observers were 15 undergraduate students in psychology (male and female). At 6 to 12.5cps, thresholds of all observers were lower than they were at 19 to 46cps. As thresholds decreased, response variability increased for all observers but three. These three observers showed large variability at 26 to 46cps (Table 1). It is clear that the decrease of thresholds, at lower range of flicker, was evoked by brightness enhancement. At above 19cps, obtained threshold was higher than that below 12.5cps. It suggests that apparent brightness of high frequency flicker obeys Talbot's law. An additional finding was that observers were divided into two types in terms of their response variability, and to confirm this finding Exp. 2 was conducted. Exp. 2: Brightness of flicker targets (4, 6, 8, 12.5, 26, 35, 46cps., 11.23mL, diameter 1°) was matched by 16 observers to that of the steady target (diameter 1°, intensity variable). At 4 to 8cps, apparent brightness enhanced and response variability increased. But there were five observers out of sixteen, who showed higher variability at 26 to 46cps (Table 4). This confirmed the above finding that there were two types of observers (majority group and minority group) as to the response variability. There was not sex difference.