Popular Science Monthly/Volume 41/September 1892/Further Study of Involuntary Movements II
|FURTHER STUDY OF INVOLUNTARY MOVEMENTS.|
PROFESSOR OF EXPERIMENTAL AND COMPARATIVE PSYCHOLOGY IN THE UNIVERSITY OF WISCONSIN.
IN a former article (Popular Science Monthly, April, 1892) various illustrations were given of the involuntary movements of the hand toward the object or locality to which the subject was giving his attention: whether he were counting the strokes of a metronome or the oscillations of a pendulum, reading colors or Fig. 1.—Device for recording Movements. The glass rod, R, moves freely up and down in the glass tube, T, held in the cork, C. The rubber band, B, prevents the rod from falling through the tube. words, thinking of a building, locality, or hidden object, a very fair though variable index of the direction of his thoughts could be derived from the involuntary movements of the hand. The record was obtained by means of an apparatus called the automatograph, the essential parts of which were a pair of glass plates, suitably mounted, and between them three well-turned brass balls; the hand rests upon the upper plate, which, upon the slightest impulse, rolls upon the balls, and the movement thus imparted to the plate is recorded. The recording device may be used separately, and is shown in full size in Fig. 1. There is a cork C, pierced by a glass tube T, within which a pointed glass rod R moves freely up and down; a rubber band B is useful in raising the pencil from the record as well as in preventing the rod from falling through the tube. The record is made upon a piece of glazed paper stretched over the glass of a ground-glass drawing-frame, such as children use for tracing outlines; the paper is blackened with lamp-soot, and the record may be made permanent by bathing it in shellac and alcohol. This recording device, without anything else, will record involuntary movements: the cork is held in the extended hand with the rod over the record-plate, which is placed upon a table; or, again, the record-plate may be held in the hand and the recording device held firmly over it. In either way we have an extremely simple means of obtaining records of involuntary movements, which any one interested
Fig. 2.—Counting Metronome, ↦ Upper line, movements of head; lower line, of hand on automatograph; time, 45 seconds. The head movements are reversed, but have been again reversed for readier comparison. Figs. 2 to 11 are all obtained upon the same subject. The arrows indicate the direction in which the object attended to was situated.
may construct and test for himself. The use of such a device is not confined to the hand; the plate or the rod may be fixed to other portions of the body.
Having shown that the hand moves toward the direction of
Fig. 3.—Counting Metronome. Facing ↦ Automatograph, sitting. I, ↤; time, 105 seconds. II, ↦; time, 45 seconds.
one's thoughts, the next important step is to determine whether this movement is altogether the expression of the subject's mental activity, and, if not, what other factors contribute to it; and, further, in what part or parts of the body it originates, what are its components, and the like. These movements have a close connection with the body as well as with the mind, and it is essential to determine in what measure each appears in the general result.
If you hold out your arm nearly on a level with the shoulders and in line with them, you perceive at once that movements of Fig. 4. ↦ Counting Metronome. Right band holds pencil, left hand holds record; time of each, 90 seconds. Facing ↦. Upper line, standing; lower line, sitting. 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 along a circle of which the shoulder is the center. What we require is a position in which movements in any 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 position is
|Fig. 5.—Thinking of a Building. Facing ↥; standing. Right hand holds pencil, left hand holds record; time of each, 60 seconds. I, ↥; II, ↧; shows respiration.||Fig. 6. Counting Metronome. Right hand holds pencil, left hand holds record. From A to B, ↥; from B to C, ↦; from C to D, ↧; from D to E, ↤; standing; each part, 45 seconds.|
recommended for the normal tests. The usual result is a movement toward the object of attention; but when that is to the rear, this tendency is sometimes outweighed by the natural tendency 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;
|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 in one hand and the pencil in the other; in this way the pencil and the plate sway alike, and no record of it is made. The very fine movements thus obtained are shown in Fig. 4; this figure also shows the slight difference between a record taken by this method while the subject is sitting and while standing, which further proves that the swaying of the body has been eliminated. Traces of periodic oscillations are noted in Fig. 4; these are due to respiration movements, and in II, of Fig. 5, they are unusually distinct and regular, about twenty to the minute. The forearm of the hand holding the record-plate rests against the body while the recording hand is held free from it, and thus the abdominal movements are recorded. The movements toward the object of attention appear
throughout. Fig. 5 figures a movement toward the rear as well as toward the front; while Fig. 6 presents a most beautifully regular movement in all four directions. As the metronome, the strokes of which the subject is counting, is carried from one corner of the room to the next, the hand involuntarily follows it and records an almost perfect square.
It is further interesting to record the movements of the two hands during the same experiment; a correspondence of movement would be attributed to a common swaying of the body, but this would not exclude symmetrical movements of the hands as well. Fig. 7 illustrates the close similarity of the movements: while Fig. 8 shows the importance of the position of the arms in such an experiment. The hand that is held away from the body moves more extensively; the form of the movement remains similar. All the above records (and Figs. 9, 10, and 14) were obtained upon the same subject; they are therefore comparable with one another, and illustrate the analysis of the resulting movements into their several factors.
Involuntary movements are not limited to the horizontal plane; we may record vertical movements by holding the recording device in a slanting position, and fixing the record-plate upon the wall. The main characteristic of such a record is the sinking of the arm from fatigue; the movement is rapid and coarse (I of Fig. 10). If the attention be directed to the front, we obtain a Fig. 10.—I, ↧ Record-plate Vertical. Thinking of one's feet. Time, 45 seconds. II, ↥ thinking of a point overhead. Time, 45 seconds. resultant of the two tendencies, as is shown in the diagonal line of Fig. 9. Fig. 10 illustrates an interesting point similar to that illustrated in Fig. 3. When the attention is directed downward, the hand falls rapidly, I; but when the attention is directed upward, very little movement at all takes place—the tendency to move toward the object of attention constantly counteracting the tendency for the arm to fall. While we have not been altogether successful in recording by these involuntary movements the various powers of different sense-impressions to hold the attention, the few successful results are especially interesting. In Fig. 11 the outline I is the movement of the hand during the thirty-five seconds that the subject was counting the strokes of a metronome; the outline II is the movement while counting for twenty-five seconds the oscillations of a pendulum. The latter movement is much more extensive than the former; the visual holds the attention better than the auditory impression. The subject of this record is a noted American novelist, and his description of his own mental processes entirely corresponds with this result. He is a good visualizer, and is eye-minded in every respect.
We turn to Fig. 12. The subject was asked to call the names of a series of small patches of colored papers hanging upon the wall in front of him. He did this with some uncertainty for thirty-five seconds, and during this time his hand on the automatograph moved from A to A'. At the latter point he was asked to count the oscillations of a pendulum; this entirely changed the movement, the hand at once moving rapidly toward the pendulum. The pendulum was a more attractive sense-impression than the colors; the special point of interest in this record is, that upon
examination the subject's color-vision proved to be defective and thus explained the failure of the colors to hold his attention.
An important problem relates to the possible correlation of types of involuntary movements with age, sex, temperament, disease and the like. A few observations upon children are interesting in this regard. They reveal the limited control that children have over their muscles, and how difficult it is for them to fix the attention when and where desired. The movements they make are large, with great fluctuations, and irregularly toward the object of attention. Fig. 13 illustrates some of these points; in thirty-five seconds the child's hand moved by large steps seven
inches toward the pendulum, and the entire appearance of the outline is different from those obtained upon adults.
Much attention has recently been paid to automatic writing, or the unconscious indication of the nature, not the direction, of one's thoughts while the attention is elsewhere engaged. We attempted this upon the automatograph by asking the subject to view or think of some letter or geometric figure, and then searching the record for some trace of the outline of the letter or figure; but always with a negative result. While unsuccessful in this
sense, the records prove of value in furnishing a valuable contrast to the experiments in which the attention was fixed in a definite direction. For example, the subject is thinking of the letter O; he does not think of it as in any special place, and the record, Fig. 14, likewise reveals no movement in any one direction. Two
records are shown quite similar in significance, and illustrating as well the difference between the movements while standing and while sitting.
We have thus illustrated a variety of involuntary movements obtained in different ways and with bearings upon many points of importance to the psychologist. They by no means exhaust the possibilities of research, or the deduction of conclusions in this field of study, but simply illustrate in an imperfect way how abundant and intricate are the expressions of the thoughts that lie within.
- The results of this paper were obtained with the co-operation of Thomas P. Carter and Edward P. Sherry, of the class of 1892, University of Wisconsin.
- It is to be noted that in this case the record will be in a direction the opposite of the real movement.
- In one series we were able to measure the extent of movements in various directions, and found half again as much movement toward the front as toward the rear, and a third again as much toward as away from the body.