What is the origin of the movements involved in these records? To what extent are they movements of the hand, of the arm, or of the entire body? Casual observation is sufficient to show that with a given position of the arm, certain movements are much more readily made than others; and the involuntary tendencies will naturally follow the lines of least resistance. If, for instance, you hold your arm nearly on a level with the shoulders and in line with them, you perceive at once that movements of the hand to the front are much more readily made than to the rear, and movements toward the body more readily than those away from the body; the tendency of the hand is to move forward in a circle of which the shoulder is the centre. What we require is a position in which movements in any one direction are as readily made as in any other; and this may be approximated, though only approximated, by holding the hand at an angle of about 45° with the line joining the shoulders, and with the elbow bent at an angle of about 120°. This was the position in most of the tests, and the usual result was a movement toward the object of attention; but when the object attended to lies in back of the subject, this tendency is sometimes outweighed by the natural tendency for the arm to move forward, and the result may be a movement forward, but a less direct movement forward than when the object of attention is to the front. In a good subject, however, the involuntary tendency is strong enough to prevail, and a movement backward results. An instance of this, obtained under other but comparable circumstances, appears in Fig. 14. It is to be noted that in this figure the tracing marked I. was obtained with the subject seated, and the metronome beating behind him; the hand after some hesitation moves backward slowly towards the metronome to a moderate extent. In tracing II., with the subject also seated, the metronome is to the front, and the hand moves directly and quickly towards it. We conclude that the position of the body is an important factor in the resultant movements, but that it does not interfere with their accepted psychological interpretation.
Fig. 14.—Counting the strokes of a metronome. Subject seated. In tracing I. the metronome is at the rear. Time of record, 105 seconds. Direction of the attention ←. Subject facing →. In tracing II. the metronome was to the front. Time of record 45 seconds. Direction of the attention →. Subject facing →. ⅘ size.
Fig. 15.—Counting the strokes of a metronome. Time of record, 45 seconds. The upper tracing shows the movements of the head recorded upon a plate resting on the head. The lower tracing shows the usual record of the hand upon the automatograph. Direction of the attention →. Subject facing →.
When observing the subject during a test, we may note the movements of the body as a whole, and of the arm or hand. The movement of the body is an irregular swaying with the feet as the centre of the movement; this swaying is most readily recorded by fixing the recording-plate upon the subject's head, and having the recording-rod held in a suitable position above it. It was found that in connection with the swaying movements there were general movements towards the object of attention; and such movements were as readily made when the object was to the front, to the rear, or to either side. To determine how far this movement is the same in head and hand, it is necessary to record both simultaneously. Fig. 15 illustrates the correspondence of the two movements. It thus becomes clear that the swaying of the body as a whole constitutes an important factor of these automatograph records; that the movements of the head (being farther away from the centre of motion) are more extensive than those of the hand; and that both head and hand are sensitive organs for the expression of involuntary movements. That the muscle-reader is aware of this fact is obvious from the usual positions which he maintains towards his subject in reading the direction of the hidden object.
Fig. 16.—Counting the strokes of a metronome. Right hand holds the pencil, and left hand holds the record plate. Direction of metronome →. Subject facing →. In the upper tracing the subject was standing; time of record, 90 seconds. In the lower tracing the subject was sitting; time of record, 90 seconds.
Fig. 17.—Thinking of a building. Right hand holds pencil, and left hand holds record plate. Subject facing ↑. In tracing I., direction of the attention ↑; in tracing II., direction of the attention ↓. Time of each record, 60 seconds. II. shows respiration records.