触空間に於けるS効果の研究 (II)

皮膚上のS効果に於ける視覚機能の役割について

抄録

In his previous study (1) the writer confirmed the appearance of the S-effect upon the skin, and pointed out the fact that the visual image accompanied this phenomenon in the normal seeings. The present investigation was designed to see whether of not the vision was an indispensable requisite for the occurrence of S-effect upon the skin. Three momentary pressure stimuli were presented in succession upon forearms and the subjegts were asked to compare the length of time interval between the second (R₂) and the third stimuli (R₃) with that between the first (R₁) and the second stimuli. The following three types of persons served as the subjects : (1) the four normol seeings (adults) (n.), (2) the two partial seeings and the two total blinds from their boyhoods (high school students) (p. s. and 1, t. b.), (3) the three total blinds from their early childhood who are comparable to the congenital total blinds (high school stuqents) (e.t.b.). All subjects were required to keep their eyes closed during experiment. Measuring eight times by the method “Das Verfahren des vollen Ab- und Aufsteigs”, the equivalents were compuited.
The main results were as follows :
1. Three stimuli were presented upon the right forearm as shown in Fig. 1. If the spatial distance between R₂ and R₃ was longer (shorter) than that between R₁ and R₂, then time interval between R₂ and R₃ was overestimated (underestimated) by n. and p.s. and l.t.b. On the other hand if both distances were equal, both time intervals appeared approximately equal for them. But such a consistent effect did not occur in e.t.b. (Exp. 1) (cf. Table 1 and Fig. 2)
2. The first and the second stimuli were presented upon the right forearm and the third stimulus was presented upon the left forearm as in Fig. 3. If the spatial distance between R₂ and R₃ was longer (shorter) than that between R₁ and R₂, then time interval between R₂ and R₃ was overestimated (underestimated) by n. and p.s. and l.t.b. But this S-effect did not occur in e.t.b. (Exp. 2) (cf. Table 2)
3. The first and the third stimuli were presented upon the right forearm and the second stimulus was presented upon the left forearm as in Figs. 4 and 5. Under the condition of Fig. 4 an illusion of spatial distarice appeared, that is, the distance between R₂ and R₃ appeared longer than that between R₁ and R₂ : moreover, time interval between R₂ and R₃ was overestimated by n. and p.s. and l.t.b. Under the condition of Fig. 5 the former distance appeared shorter than the latter ; besides, time interval between R₂ and R₃ was underestimated by them. On the other hand, such an illusion of distance and S-effect as mentioned above did not take place in e.t.b. (Exp. 3) (cf. Table 3)
Thus it has been found that the S-effect appears in the partial seeing and the total blind from his boyhood as in the normal seeing, and that the manner of visual interference in recognizing temporal length in the former is the same as that in the latter ; besides, the S-effect does not appear in e.t.b. Taking the above-mentioned facts into consideration, it may be concluded that the vision is an indispensable requisite for the occurrence of S-effect upon the skin.