Quite a number of delusions find a common point of origin in the natural tendency to view our mental life—the aggregate of our thoughts and doings—as coextensive with the experiences of which our consciousness gives information and which our will directs. The significance of the unconscious and the involuntary is apt to be underestimated or disregarded. We are more ready to acknowledge that in certain unusual and semi-morbid conditions persons will exhibit these peculiar expressions of the subterranean strata of our mental structure—that some have the habit of walking or talking in their sleep, that others occasionally fall into an automatic, trance-like condition, that hypnotism and hysteria and obscure lapses of consciousness and alterations of personality bring to the surface curious specimens of the mysteries of this underworld,—but we are slow to appreciate that the subconscious and the involuntary find a common and a natural place amidst the soundly reasoned and aptly directed activities of our own intelligence. While it is reasonable and proper to have faith in the testimony of consciousness, it is desirable that this confidence should be accompanied by an understanding of the conditions under which such testimony is presumably valid, and when presumably defective or misleading. Sense-deceptions, faulty observation, distraction, exaggeration, illusion, fallacy, and error are not idle abstract fancies of the psychologist, but stern realities; and their existence emphasizes the need in the determination of truth and the maintenance of a sound rationality, of a calm, unprejudiced judgment, of an experienced and balanced intelligence, of a discerning sense for nice distinctions, of an appreciation of the circumstances under which it is peculiarly human to err. A demonstration of the readiness with which perfectly normal individuals may be induced to yield visible evidence of unconscious and involuntary processes, thus possesses a special interest; for when the naturalness of a few definite types of involuntary movements is made clear, the application of the experience to more complex and more indefinite circumstances will easily and logically follow. While the circumstances under which involuntary indications of mental activity are ordinarily given, are too various to enable one to say ab uno disce omnes, yet the principle demonstrated in one case is capable of a considerable generalization, which will go far to prevent misconception of apparently mysterious and exceptional phenomena.

II

When some years ago, the American public was confronted with the striking exhibitions of muscle-reading, the wildest speculations were indulged in regarding its true modus operandi; and the suggestion that all that was done was explicable by the skillful interpretation of the unconscious indications given by the subjects, was scouted or even ridiculed. It was not supposed that such indications were sufficiently definite for the purposes of the "mind-reader," or were obtainable under the conditions of his tests. Again, it was urged that this explanation was hardly applicable to certain striking performances, which in reality involved other and subtler modes of thought-interpretation, and the accounts of which were also exaggerated and distorted. And furthermore, it was argued, too many worthy and learned persons were absolutely certain that they had given no indications whatever. For a time the view that mind-reading was muscle-reading rested upon rather indirect evidence, and upon a form of argument that carries more weight with those familiar with the nature of scientific problems than with the public at large. But the development of experimental research in the domain of psychology has made possible a variety of demonstrations of the truth and adequacy of this explanation. It was with the purpose of securing a visible record of certain types of involuntary movements, that the investigation, the results of which are here presented, was undertaken.

To eliminate the record of the swaying of the body, we may experiment with the subject seated; we obtain a distinctive record in which certain phases of the fluctuations have almost disappeared, and in which the record approximates to a straight line (tracing II. of Fig. 14). One may also eliminate the record of the swaying by dispensing with the automatograph, and simply holding the recording plate in one hand and the recording device or pencil in the other; for then the plate and pencil sway together, and naturally no record of it is made. The relatively fine movements thus obtained are shown in Fig. 16; the contrast between this record and such records as Figs. 4, 5, 6, is mainly the contrast between a record in which the general swaying of the body is registered, and one from which it has been eliminated. It is interesting to note that in records thus taken, there is but a slight difference in the result when the subject is standing and when he is sitting; which is a further proof that the swaying of the body has been eliminated. (Compare these with Fig. 14.) Traces of periodic oscillations are noticeable in Fig. 16; these are due to movements of respiration, and in tracing II. of Fig. 17, they are unusually distinct and regular, about twenty to the minute. In this case the forearm of the hand holding the record plate was braced against the body, while the recording hand was held free from it; and thus the abdominal movements were registered. The movements toward the object of attention appear throughout. Fig. 17 shows a movement towards the rear of the subject, as well as towards the front; which again shows that under suitable conditions, involuntary movements may be recorded in one direction as readily as in another. Fig. 18 presents a most beautifully regular movement in all four directions. As the metronome, the strokes of which the subject was counting, was carried from one corner of the room to another and so on around the room, the hand involuntarily followed it and recorded an almost perfect square. So striking and regular and so varied an involuntary movement, in conformity with changes in the direction of attention, one can expect to secure but seldom, and then only with a good subject.

The outline presented in Fig. 19 was obtained in a test in which the movements of the hands were separately recorded, in order to determine the degree of correspondence between them. The result shows a marked general resemblance, indicating in part a common origin of the two movements. The next figure, Fig. 20, shows that this correspondence is dependent in part upon the similarity of the positions of the two hands. The hand that is held away from the body moves more extensively; but the form of the movements remain similar. The records reproduced in Figs. 14-22 and 26 were obtained upon the same subject, though with slightly varying conditions, and are fairly comparable with one another, and thus illustrate the analysis of the resultant movements into their component factors.

Involuntary movements are not limited to the horizontal plane; vertical movements may be recorded 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 through fatigue; the movement is rapid and coarse (tracing I. of Fig. 20). If the attention be directed to the front, we obtain a resultant of the tendency to move towards the object of attention, and of the sinking of the arm, as appears in the diagonal line of Fig. 22. Fig. 21 illustrates an interesting point similar to that illustrated in Fig. 14. When the attention is directed downward, the hand falls rapidly (tracing I.); but when the attention is directed upward, very little movement at all takes place,—the tendency to move towards the object of attention constantly counteracting the tendency for the arm to fall (tracing II.).

V

While I have not been altogether successful in determining by this method the relative efficiency of different sense-impressions in holding the attention, the successful results are especially interesting. In Fig. 23 the tracing marked I. shows the movement of the hand during the thirty-five seconds that the subject was counting the strokes of a metronome; tracing II. shows the movement while counting for twenty-five seconds the oscillations of a pendulum. The latter movement is in this case much more extensive than the former, thus indicating that the visual impression held the attention much better than the auditory. The subject of this record is a well-known writer and novelist; and his description of his own mental processes entirely accords with this result; he is a good visualizer, and visual impressions and memory-images dominate his mental habits.

We may next turn to Fig. 24. The subject was asked to call the names of a series of small patches of color 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 accounted for 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 respect. They reveal the limited control that children have over their muscles, and their difficulty to fix the attention when and where desired. Their involuntary movements are large, with great fluctuations, and irregularly towards the object of attention. Fig. 25 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 merely the direction of one's thoughts, while the attention is elsewhere engaged. I 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 letter or figure; but always with a negative result. While unsuccessful in this sense, the records prove of value in furnishing a salient 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. 26) 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.

VI

There have thus been passed in review 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 they may serve to illustrate how subtle and intricate are the expressions of the thoughts that lie within. That involuntary movements are by no means limited to the type here illustrated is easily shown. In the exhibitions of muscle-reading, the changes in breathing, the flushing, the tremor of the subject when the reader approaches the hiding-place, and the relative relaxation when he is on the wrong scent, serve as valuable clues; to borrow the apt expression of "hide and seek," the performer grows "hot" and "cold" with his subject. Then, too, the tentative excursions in one direction and another, to determine in which the subject follows with least resistance, present another variation of the same process. The hushed calm of the audience when success is near, the restlessness and whispering during a false scent, are equally welcome suggestions which a clever performer freely utilizes, thereby adding to the Éclat of his exhibition. When a combination of numbers or of letters in a word is to be guessed, the operator passes over with the subject the several digits or the alphabet, and notes at which the tell-tale tremor or mark of excitement occurs, and so again performs the feat on the basis of the involuntary contractions that express the slight changes of attention or interest when the correct number or letter is indicated. In much the same way we unwittingly betray our feelings and emotions, our interest or distraction or ennui; the correct interpretation of these in others and their suppression in one's self form part of the artificial complexity of social intercourse. But in the line of experimental demonstration also, another form of involuntary movement has been brought forward in recent years by the investigation of Hansen and Lehmann upon "involuntary whispering." This investigation brings out the fact that many of us, when we think intently of a number, tend to innervate the mechanism appropriate to its utterance. We do not actually speak or whisper the word or sound, but we initiate the process. If one person thinks of a number,—say from one to ten, or from one to one hundred,—and the other records any number which at the same moment suggests itself to him, it may result that the proportion of correct or partially correct guesses exceeds that which chance would produce; and arguments for telepathy have been based on such results. In the series of experiments in question these "involuntary whisperings" were not severely suppressed,—much as in the automatograph tests one might determine to let the glass move if it would. It must be understood that there was no true whispering nor any movement of the speaking mechanism which a bystander could detect; and yet it seems likely that the one participant was influenced in his guessing by the vague but yet real, subconscious, embryonic articulation of the other. The proof of this lies mainly in the analysis of the successes and errors; for the confusions are strikingly between numerals of somewhat similar sound,—as between fourteen and forty, or sixty and thirty, or six and seven. If the two persons are seated in the respective foci of two concave surfaces which collect the sound (thus in a measure paralleling the exalted sensibility of specially gifted or hypnotized subjects), the chances of success seem to be increased. While the investigation is both complex and incomplete, yet the general trend of it is sufficiently clear to make it probable that "involuntary whispering" serves more or less frequently as a subconscious and involuntary indication of thought. It shows again that below the threshold of conscious acquisition and intentional expression lie a considerable range of activities, which though they blossom unseen do not quite waste their fragrance, but come wafted over in vague and subtle essence. The falling of a drop of water is unheard, but the sound of the roaring torrent is but the sound of myriads of drops. The boundary between the conscious and the unconscious is broad and indefinite; and vague influences, if not direct messages, pass from one side to the other.

The general bearing of the study of involuntary movements I have indicated at the outset; and no elaborate comment on the practical significance of the results described seems necessary. They certainly facilitate the appreciation of the reality of the subconscious and the involuntary; and in connection with explanations of muscle-reading or telepathy, they illustrate how naturally a neglect of this realm of psychological activity may lead to false conclusions. They bring a striking corroboration of the view that thought is but more or less successfully suppressed action, and as a well-known muscle-reader expresses it, all willing is either pushing or pulling.