Page:Popular Science Monthly Volume 41.djvu/657

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639
FURTHER STUDY OF INVOLUNTARY MOVEMENTS.

for the arm to move forward, and the result is then a smaller and less direct movement forward than when the object of attention is to the front. An instance of this, obtained under other but comparable circumstances, appears in Fig. 3, while Figs. 5 and 6 illustrate the more usual result. We conclude, then, that the position of the body is an important factor, but does not detract from the accepted psychological interpretation of these movements. While observing the subject we may note 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 point of attachment, and this we recorded by fixing the recording plate upon the subject's head, and suspending the pencil above it. It was found that the head like the hand moved toward the object of attention;

PSM V41 D657 Automatograph trace of building with different hands and positins.jpg
Fig. 7.— Thinking of a Building. Standing. . I, left hand; II, right hand; both holding record near the body; time, 35 seconds; records reversed. Fig. 8.— Thinking of a Building. Facing. . I, left hand held extended far out; II, right hand held close to body; each hand holds record; time, 35 seconds; records reversed.

and, further, that it moved as readily toward the object when the latter was to the front, to the rear, or to either side. To determine how far this swaying is the same in head and hand, we record both at the same time. Fig. 2 illustrates the correspondence of the two movements. From a number of such tests we conclude that the swaying of the body contributes an important factor to the automatograph records, and that the movements of the head are apt to be more extensive than those of the hand.

To eliminate this swaying of the body, we may experiment with the subject seated; we then obtain a distinctive record II (of Fig. 3), in which the oscillations have almost disappeared, and in which the tendency to move along a circle is marked. A still better method of eliminating this swaying is to hold the recording plate