抄録
Tactual perception of length (or distance) is said to be inferior to visual one in its clearness and its steadiness. To test this assumption, we tried some ex-periments on the visual one in various circumstances.
Experiments: Four manners of presentation of length-(or distance-) stimuli were used. They were: M1-Straight light-line (2mm wide); M2Track of a running light-spot (2mm2 in size, 3cm/sec or 7.5cm/sec in speed); M3-Distance between two light-spots (2mm2 in size) simultaneously presented; M4-Distance between two light-spots (same size as above) successively presented in various time-intervals.
In each case, they were presented horizontally, as high as the O's eyes, and 1.8m apart from him.
O was to compare the two lengths (or distances) both presented in the same manner to each other, which were given successively at almost the same position (time-interval between them was always 3 sec).
Procedure was Wirth's method of “complete series” Standard was 15cm, variables were nine kinds (from 9cm to 21cm, differential by the step of 1.5cm).
Results: (1) In M1 and M3, length (or distance) was perceived, even in the complete dark room, as clear as in daily circumstances, and the comparison was also executed very easily and decidedly.
(2) In M2 and M4, the length-experience was poor and lacking in clearness, no matter whether the stimuli were given in the complete dark room, or on the homogeneous wide-spread plane. All O's felt uncertain with their own judgments, processes of which were rich in variety. Sometimes, especially in M4, judgments were wholly dependent on the abstracted time-relation between the two stimuli.
(3) But, even in such disadvantageous manners as M2 and M4, the more differen-tiate the circumstances around the compared were, the more easily the com-parison was executed.
On the basis of such data as above mentioned and some others, we investigated the phenomenal factors determining the appearance of length.
