Clever Hans Part 5

In the case of smaller numbers, on the other hand, one often obtained correct results without counting. In this I am borne out by Mr.

Schillings. It was merely necessary to image vividly the number 3, or 4, or even the name of a week-day or of a month without the number which would indicate it. In the last of these cases the number corresponding to the day or the month (e. g. 3 for Tuesday, 5 for May, etc.), though not consciously presented, still evidently lay at hand in the subconscious. To use a popular expression, I usually had a "feeling"

when Hans had arrived at the right number.

It was furthermore found that it was not only necessary to count to, or to think of, the number desired, but that this must take place with a high degree of tension of expectancy--that is, a strong affective element must enter in. The state required for a successful response was not the mere pa.s.sive expectation that the horse would tap the number demanded of him nor the wish that he might tap it, but rather the determination that he should do it. An inward "Thou shalt", as it were, was spoken to the horse. This affective state was registered in consciousness in terms of sensation of tension in the musculature of the head and neck, by intraorganic sensations, and finally by a steadily rising feeling of unpleasantness. When the final number was reached, the tension would suddenly be released, and a curious feeling of relaxation would ensue. I have made a series of tests to determine the most favorable degree of tension in expectation. It was possible to distinguish with certainty, three degrees of tension besides the state of utter relaxation,--all of which I measured by means of the differences in the sensations of tension. In cases of tension of the first degree (greatest concentration) the responses were usually correct, a few, however, were lacking by one unit. There was therefore in the latter instance a premature release of inner tension. In cases of tension of the second degree all answers were correct except a very few which were too great by one unit. In cases of tension of the third degree, many answers were wrong, and usually by several units too many.

I wished to have the horse tap 10, with the lowest degree of concentration. He tapped 13, then in a repet.i.tion of the test, 12. I thereupon increased the tension, Hans then tapped 8. I decreased the tension once more, but so that it was somewhat greater than at first.

Hans tapped 10 correctly. At another time I tried to have him tap the number 5, with a low degree of tension. He tapped 6. I intensified expectation and Hans tapped 4. I again decreased it, and he tapped 5, _comme il faut_. Apparently, therefore, the most favorable degree of tension was one between the first and second,--the latter being the least favorable. After some practice a lesser degree than was used in the beginning sufficed to evoke adequate reactions. The flow of nervous energy to the motor centers of the brain evidently became facilitated through practice. It will be easy to understand why the first days of experimentation caused intense headaches, which later never occurred.

Whenever, in the foregoing, we spoke of a certain degree of concentration which had to be attained, it is not to be understood that the same tension had to be maintained throughout the test, from the horse's first tap to his last. But rather, that it began with a low degree, and gradually increased as the final unit of the count was being approached. It may best be represented by a curve whose maximum represents that degree of tension which we have been discussing. The rise to this maximum which, when attained, was followed by a sudden fall, did not always occur in the same manner. Three types of curve may be distinguished, which were first discovered in purely empirical fas.h.i.+on, and later reproduced voluntarily for purposes of experimentation by diagramming before each test the intricate curve of the varying degrees which the intensity of concentration was to a.s.sume.

The types may be described as follows:

I. Here the tension curve rises steadily from beginning to end. This type preponderates in the case of small numbers. Thus, when I asked the horse: "How much is 2 plus 4?", the tension increased slowly with every tap from the moment I began counting, until the final tap was reached, when it was again relaxed. Externally this relaxation is noticeable as a slight jerk.

II. In this case the curve does not rise at an equal rate, but rather more slowly at the beginning and later undergoes a sudden increase, or the tension increases immediately at the beginning, remains constant for some time and then ascends to the maximum. This curve is the rule in the case of large numbers and evidently means economy of physical energy, for experience soon taught that a steady increase in tension from the very beginning soon brought it to a level which cannot be long maintained and usually leads to a premature relaxation. In the case of very large numbers the alternation of the slight and the sudden increase may be repeated several times, and at times it may even sink below a level which has already been attained, thus making a wave-like curve.

III. The third type of curve shows a sudden jump between two units at a certain point in its course. This may occur in the case of both small and large numbers but only when the highest or first degree of concentration is employed (see page 91). Such a jump frequently occurs in the transition from the tap preceding the last to the last one which is being eagerly expected. Relaxation--with the upward jerk and raising of the head--here occurs at the normal time; Hans taps to the end with his right foot. Oftener still the "jump" described occurs while pa.s.sing over to the number just before the last. The goal seems within reach and the mental tension relaxes, and with it the physical tension,--the head gives a slight jerk and Hans makes the back-step. Since, however, another tap is still awaited with some degree of tenseness and, since complete erection of the head does not follow immediately upon the jerk of the head, the horse gives another tap with the left foot. Thereupon occurs the complete relaxation of attention, and the a.s.sumption of the erect posture on the part of the questioner. That this is psychologically the clue which leads to the final tap, will readily appear from the following remarkable fact: I was able to bring about at will either the back-step with the right foot, or the additional extra tap with the left foot by concentrating the mind either upon the last unit or upon the one just preceding it. In either case the movement which served as stimulus to the horse followed naturally upon concentration on the number. I could of course also control the response by direct voluntary control of the movements involved. Hans thus solved for me the same ten problems first with the back-step, then with the extra final tap.

Finally we will indicate the one true inner cause of the difficulty in getting the number 1 as a response. It is not easy to relax attention immediately after having just begun to concentrate. Relaxation, therefore, often occurs with a certain r.e.t.a.r.dation, and the result is a belated jerk of the head.

Briefly, I would also mention a few of the more interesting introspective observations which were made in situations in which the horse responded with movements of the head for answers such as "yes" and "no", "up" and "down", etc. From the very beginning I put questions to Hans which would have to be answered by a shake of the head. It often happened that instead of indicating "0", Hans would begin tapping some number. But the wonder of it was that, in many cases, he responded properly. I knew only that I inwardly p.r.o.nounced the word "null" (zero), and that I looked expectantly at the horse's head. In the case of questions to which I expected the answer "yes" or "no", I imagined myself enunciating the answer, i. e., I used motor imagery. The tests failed, the moment I employed only visual or auditory imagery, whereas, motor imagery was always effective in calling forth correct reactions.[M] When the proper response was "up" and "down" I would think of those directions in s.p.a.ce, and likewise with "left" and "right"

in which case also I would put myself in the horse's place.

[Footnote M: Thus it is possible to think of the word "no" in three different ways. I may get a visual image of the written or printed word, or the auditory image of the word as spoken by another person, or finally I might think of it in terms of images of the sensations of movement which would arise if I myself were to enunciate or write the word. And so, in like manner, I could think of any other word in terms of either visual or auditory or motor imagery. In all probability the auditory and motor always occur together,[6] but still it is possible to make the one or the other predominate.

It appears that the imagery of most persons is a mixture of auditory-motor and visual elements, with a predominance of one or the other kind. Individuals who utilize almost exclusively the visual (as does the author, as a rule), are rare. But rarer still is the p.r.o.nounced motor type.]

While I was still ignorant of the nature of the necessary movements, the tests were successful only when I had put the question aloud or in a whisper, but never when I failed to enunciate, i. e., when I merely had the question in mind ("in idea"). But this also became possible after a little practice, although I could not then give an explanation for my success. Except in one instance, we could discern no difference between problems spoken and those merely conceived by Mr. von Osten who had had the advantage of long practice. But the one exception deserves mention.

The old gentleman commissioned Hans, presumably without uttering a word, to step backward to the left. Hans thereupon responded by giving his entire repertoire, as follows: He moved his head to the right, then to the left. Then he leaped forward and repeated the same movement of the head. Hereupon he stepped backward and signified a "yes" by a movement of the head. He then lowered his head and made two leaps forward. After this performance Mr. von Osten repeated the same command aloud, and in every case Hans responded properly. Again the silent command was given and again the horse responded with the series of reactions described above, lowering his head leaping forward, etc. In this experiment, without exception, the spoken command evoked adequate reactions,--the silent command, an incorrect response. Evidently the impulse to movement was not so great with the mere conceiving of "right", "left", etc., as when the words were enunciated. It, therefore, required some practice on my part before a sufficiently strong movement-impulse became a.s.sociated with the idea. All this is in no wise at variance with the fact that tests involving counting and computation were as successful when the problem was given in silence, as when it was spoken. The signs for tapping, viz.: inclination and erection of the head and body, followed the question. The question therefore became superfluous. On the other hand the signs for head-movements on the part of the horse, were given while the question was being put. I ask, which way is "upward", and at the same time I look upward. In this case therefore the question itself is not entirely insignificant.--I experienced greater difficulty in getting Hans to respond with the head-movement to the left. After much practice I was able to evoke this movement by means of giving the command aloud, but never by means of the "silent" command. Accidentally I hit upon a device by means of which I attained this end also. I asked the horse aloud "Which direction is left?",--whereupon he reacted properly; then I immediately repeated the question silently, and was successful every time. My mental att.i.tude here was still the same as when I put the question aloud. What sort of an att.i.tude this was, I could not, of course, have stated explicitly at the time. I could not, therefore, awaken it at will,--and if I allowed but a minute to elapse between the spoken and the silent question, the vivid after-effect (the so-called "primary memory image") soon disappeared and the test was wholly unsuccessful. Practice, however, soon helped me to overcome this last difficulty also. I believe that my inability to evoke this specific reaction on the part of the horse, lay in the unfavorable position which I a.s.sumed, for it did not allow the horse to perceive my movements easily. For the same reason, Hans would at first indicate "no" and "zero" by turning to the right, seldom to the left.

As in the case of counting, a high degree of concentration was also necessary here, but with this difference, that here attention was directed to ideas present to the mind, ("yes", "no", etc.), whereas in the counting process attention was directed toward expected sensory impressions (i. e., the taps of the horse).

All that has been said thus far is readily understood psychologically.

The following curious fact, however, is noteworthy. Hans used the head-movement to indicate two such different concepts as "zero" and "no"; it appeared therefore that in both cases he was receiving the same kind of directive. Observation proved that such was the case and the directive in question was none other than an imitation in miniature, or rather a movement antic.i.p.atory of the expected head-movement of the horse. Now, whereas the signs for "up", "down", "right", and "left" were natural expressive movements which are normally a.s.sociated with the corresponding concepts, this cannot be said to be true of "no" and "zero". My laboratory observations (see page 107) lead me to conclude that the movements, by means of which the concepts "no" and "zero" are naturally expressed, are quite different; and neither of these corresponds to the signs for "zero" and "no" which the questioner involuntarily gave to Hans. What was the genesis of these unnatural forms of expression? If we might a.s.sume that the questioner always had in mind the movement he awaited on the part of the horse, and never thought of "zero" or "no", then the contradiction would solve itself.

But I must deny decidedly that I ever thought of the movements of the horse's head, and Mr. Schillings, whom I questioned on this point, agreed with me in this, in so far as his own mental processes were concerned. I can see nothing for it but that in this instance the expressive movements normally connected with the concepts "zero" and "no" have been replaced by other forms, without the questioner becoming aware of it. That such displacements may occur, has been shown by the tests described on pages 107 to 112. That they did occur in this instance may be concluded from the following observation. In responding to me, as well as to Mr. Schillings, Hans always moved his head first to the left, then to the right, never in the opposite order. That this was _not_ a peculiarity of the horse, but must be ascribed to the signs which were given him, is shown by the possibility of inverting the order under experimental control (page 77). Frequently Mr. Schillings and I had seen the horse respond to his master by means of such head-movements, and the order was always, without exception, the one mentioned. It must be a.s.sumed therefore that the horse's movement, which we so often noticed, made such an impression upon us, that afterwards it was regularly reproduced on our part quite unconsciously, so that Mr.

Schillings never, and I only after a long time, became aware of the whole process.

In closing, just a word as to the discovery of our own movements. I soon noticed that every p.r.o.nounced raising of the head or trunk brought about an interruption in the horse's response. But only by observing the final movement in the case of Mr. von Osten did I discover that I, too, performed a slight erection of the head. Observation of others was less difficult than the observation of one's own movements. As in the case of all other signs given to the horse, these movements were so slight that they were p.r.o.ne to escape notice even though one's whole attention were concentrated upon their detection. I also questioned whether in my attempts to disturb the horse by means of loud calls, it were really the call or some simultaneous involuntary movement which was the true cause of the interruption. The doubt was justified, for when I finally learned to cry out vehemently without making the slightest move, all my crying was in vain. Also it had seemed to me at first as if I were able to induce the horse to rear, not only by means of the proper sign or movement, but also by a mere command, but I found later that in every case there was always some movement, were it ever so slight. Finally I tried to simulate voluntarily the oft-mentioned involuntary jerks of the head. Although it is not very difficult to execute them at will with almost the same minuteness as when they were performed involuntarily, I still did not succeed in getting a series of such jerks of equal fineness throughout. In spite of (and partly on account of) the most concentrated attention, there would be from time to time a jerk of somewhat greater extent and energy. As soon as the movement had been executed, I was able to form a good judgment as to its relative extent, but I was unable to regulate the impulse beforehand.

With the following comment the chapter will be concluded. Introspections are necessarily subjective in character. If they are to possess general validity, they must be borne out by evidence furnished by others--and this to a greater extent than is necessary for other forms of observation. It was hardly possible to get corroboration from the other persons who had worked with Hans, for, although some of them were excellent observers of external natural phenomena, few of them had had the necessary amount of practice in introspection. The necessary confirmation, however, was had in laboratory tests, which we shall presently describe.

CHAPTER IV

LABORATORY TESTS

The tests which are to be briefly reported here, were begun in November, 1904, and were carried out at the Psychological Inst.i.tute of the University of Berlin. The purpose was twofold: first, to discover whether the expressive movements noted in Mr. von Osten, Mr. Schillings, and others, were to be regarded as typical and to be found in the majority of individuals,--and secondly, to ascertain in how far the psychical processes which I had noted in my own case and which I believed to lie at bottom of these movements, were paralleled in, and confirmed by, the introspections of others. The effort was made to make the experimental conditions as nearly as possible like those under which the horse had worked. The affective atmosphere which colored the situations in which the horse took part, could not, of course, be transferred, but this was in some respects an advantage. One person undertook the role of questioner, another--myself--that of the horse.

The experiments fall into three groups, corresponding to the types of the horse's reactions: 1, tests in counting and computation; 2, tests in s.p.a.ce reactions; 3, tests in fetching or designating objects.

In the experiments in counting and computation, the questioner, standing at my right, thought with a high degree of concentration of some number (usually between 1 and 10, but sometimes also as high as 100), or of some simple problem in addition. Then I would begin to tap,--but in human fas.h.i.+on with my right hand, rather than with my foot--and continued until I believed that I had perceived a final signal. I thus tested, all in all, twenty-five persons, of every age and s.e.x (including children of five and six years), differing also in nationality and occupation. None of them was aware of the purpose of the experiments. It could not escape them, to be sure, that they were being watched. It was also evident to them that the things noted were certain tensions and movements; but none of my subjects discovered what the particular phenomena were that I was looking for. Only in a few isolated instances did they report that they were conscious of any movements on their part.

With the exception of two persons, they all made the same involuntary movements which were described in chapter II, the most important of which was the sudden slight upward jerk of the head when the final number was reached. It was at once evident that the direction of this jerk depended upon the position which one had asked the subject to a.s.sume at the beginning of the test, the direction changing whenever the position was changed. Thus, if the subject stood with head bowed--the body either being held erect or likewise bowed,--then release of tension would be expressed physically by an upward jerk. (Occasionally the entire trunk is slightly raised, so that it was possible to observe this physical reaction when standing behind the subject). If the subject had bent his head backward, the "psychological moment" was marked by a forward movement, (although under certain conditions the head was, in such a case, observed to bend still farther backward). If during the tests the head was bent slightly to the right, then the reaction was expressed in a movement toward the left, and _vice versa_, if it had been on the left, it was bent to the right. If the subject had been bending his head forward and to the right, he then raised it upward and to the left, etc. In all of these changes of position I noticed an intermediate posture which, to be sure, it was not always an easy matter to discover,--viz.: an upright position in which there was discernible no manner of head-movement or only a slight tremor. If the subject was lying on his back with his head supported, then there was noticeable a very slight movement to one side. In this same way a number of other positions were tested in order to discover for each the characteristic movement expressive of release of tension. It would therefore appear that the raising of the questioner's head, which served as the signal for stopping for Mr. von Osten's horse, was but one instance of a general law which may perhaps be stated thus: The release of muscular tension which occurs with the cessation of psychic tension, tends to bring about that position of the head (and body) which, at the time, represents the slightest amount of muscular strain.--These movements seldom were p.r.o.nounced enough to be compared to motion through a distance of one millimeter, in a very few cases only did they attain to the magnitude of one or two millimeters: I failed to note them entirely, however, in only two individuals, two scientific men whose mode of thought was always the most abstract, and one of these was, in spite of repeated attempts, unable to elicit any response whatever on the part of the horse.

In the cases of the more suitable subjects I was able to indicate not only the number they had in mind, but also the divisions in which the number was thought, thus 12 as 5 and 5 and 2, or the same number as 2 and 5 and 5, and I was also able to determine the addends in the addition--i. e., whether the problem had been conceived as 3+2=5 or as 2+3=5. It frequently happened that in the beginning I would sometimes mistake these subdivisions, which were recognizable by the less p.r.o.nounced jerks, for the final number. Thus I would often respond with 4 instead of 8, or 3 instead of 9, or with 3 when the problem was 3+2, just as Hans had so often done. In these tests, too, the difficulty of getting the number 1, as well as the larger numbers, came to light. Thus three times in succession 17 was indicated as 4, as 9, and as 17. But after some practice I was able to give numbers as high as 58 and 96. The frequency of the errors of one unit too many and of one unit too few is also noticeable in these tests.

We also found desirable corroboration, by trustworthy subjects, of the introspective observations of the author, which were reported in Chapter III, with regard to the significance of concentration and the curve of attention. It is hardly necessary to mention that no attempts were made to influence the subjects in their accounts by asking suggestive questions. The most valuable feature about these tests was that the mute horse had now been replaced, as it were, by an animal capable of speech, and that it was now possible to follow the same process both from within and from without. Two ill.u.s.trations may be welcome. The one who took the part of the horse gave three taps and made the following entry: "At 3 I saw a slight upward jerk of the head on the part of the questioner". The questioner however had thought of 4, and made the following note, without knowledge of the other's entry: "I was aware of extreme tension, so that it was impossible for me to get beyond 3". Or again, the 'horse', reacting to a movement on the part of the questioner, stopped at 3, but the latter, having intended to obtain 2, made the following entry: "I noted clearly that I ceased thinking of the number too late, and did not put on the brakes, as it were, until I had arrived at 3". We see that errors here were entirely the fault of the questioner, just as had been the case in the tests with Hans. (See page 151f.).

In a second group of experiments I asked a subject to fix his mind upon certain concepts, such as "up", or "down", "right" or "left", "yes" or "no", and others, in any order he pleased, but with the greatest possible degree of concentration. The subject each time had the choice of four or six concepts, and he was told to think of one of them at the signal "Now!". How he was to 'think' the concept was left entirely to him. He was also told to interpolate the series with a 'blank', that is, to think of nothing at all. Standing opposite the subject, I tried to guess at the mental content of the person's mind, on the basis of expressive movements. Sometimes I reacted by shaking or nodding the head, etc., just as Hans had done, but as a rule I was content to say the word which I thought the subject had in mind. With twelve subjects (a total of 350 tests) I made an average of 73% correct responses, and in the more favorable cases I attained even 90 to 100% correct responses. Very slight involuntary movements of the head and eyes, which showed but little individual variation, and always occurred when the subject began to fix upon the concept, were the signs which I used as cues. As in the case of the movements expressive of the release of tension, which I discussed above, these movements, too, occurred without the subject being aware of them, (except in those rare cases in which they had once or twice been especially p.r.o.nounced). Indeed, it was very difficult and in some cases almost impossible for those persons whom I had initiated into the secret, to inhibit them voluntarily. "Up" and "down", "right" and "left", were expressed by movements of head or eye in those directions, "forward" by a forward movement of the head, "back"

by a corresponding movement. "Yes" was accompanied by a slight nod of the head; "no" by two to four rapid turnings of the head to either side.[N] "Zero" was expressed by a movement of the head describing an oval in the air. Indeed, it was even possible to discover whether the subject had conceived of a printed or a written zero, for the characteristics of both were revealed in the head-movements. I was able later to verify this graphically. With Ch. as subject, I made 70% correct interpretations in a total of 20 tests; with von A. as subject, 72% in a total of 25 tests. And finally I was able to interpret the signs without any errors at all. It was not absolutely necessary to look directly at the subject's face. Even though I focussed a point quite to one side, so that the image of the subject's face would fall upon a peripheral portion of my retina, I still was able to make 89% correct interpretations in a total of 20 tests.--This is not astonis.h.i.+ng after all, when we recall that the periphery of the retina possesses a relatively high sensitivity for movement impressions, although its chromatic sensitivity is very low.[O]

[Footnote N: It was Charles Darwin[7] who first pointed out that the expressive movements (of the coa.r.s.er sort) to be noted in nearly every race and people show a great, though by no means complete, similarity. The similarity is most p.r.o.nounced in the shaking of the head to signify negation and nodding to denote affirmation. It will be noted that the former is essentially of the nature of a turning toward, and the latter a turning away.[8] These same movements have been reported in the case of the blind and deaf Laura Bridgman,[9]

and we have been explicitly a.s.sured that they were a spontaneous development, and not acquired by imitation. For it is by imitation and never before the completion of the first year, that our children acquire these movements. On account of his unreliability, we can put but little stock in the statement of Garner,[10] a writer on the speech of monkeys, that these same gestures have been observed in the case of those animals. My experiments show that the same movements, greatly diminished in scope, as a rule accompany the mere thought of "yes," "no," etc. I cannot, however, regard the a.s.sertion as an established fact that every thought process whatsoever is connected with some form of muscular movement, as has been generalized by the French physiologist Fere,[11] and the American psychologist Wm. James.[12]]

[Footnote O: The productions of mind-readers, so-called, also, are based upon the perception of involuntary movements, insofar as they are not based upon pre-arranged schemes and trickery. But there we have to do princ.i.p.ally with tactual perception, since the reader touches the hand of the subject and is guided by its tremor. Some of the expert mind-readers, however, conduct tests without touching the subject. They depend chiefly upon auditory impressions: the sound of footsteps,[13] involuntary whisperings[14] and the changes in the subject's respiration[15] and the murmuring of the spectators. To a less degree visual signs also are involved: posture and facial expression of the subject, and movements of eyes and lips.[16] Even the heat radiating from the person's body is supposed to have some influence.[17] And my own experience has taught me that surprising results may be obtained by the utilization of the movements described in the preceding chapter.

It may be that these truly microscopic movements also play some part in bringing about the success of some of the experiments in telepathy, so-called, (transference of thought from one person to another, ostensibly without any mediation of the senses known to us.) In spite of the huge ma.s.s of "experimental evidence" which has been collected, chiefly in England and in America, it appears to me that telepathy is nothing but an unproven hypothesis based upon experimental errors.]

It was a.s.sumed, as indicated on page 99, that in the case of Mr.

Schillings and myself the movements naturally expressive of "zero" and "no" had been displaced--without our being aware of the fact--by others, viz.: those which the horse required as directives for his reactions. Since this was the case, we tried to discover if a similar displacement could be brought about experimentally. The attempt was successful and we discovered that under suitable conditions we could cause the subject--quite without knowledge on his part,--to establish an "a.s.sociation" between any given concept and any given expressive movement. The following experimental series will serve to ill.u.s.trate this fact.

I had one of the subjects (von A.) think of "left" and "right" in any order he chose. (The command was purposely given only in a general way: "Think of 'right' or 'left'".). We had agreed that I was to try to guess the mental content of the subject's mind, but I was not to utter a word.

Instead, I was to indicate "right" in every case by an arm movement downward, and "left" by a movement upward. To the subject I gave a fict.i.tious but plausible reason for all this. The behavior of the subject took the following course: In the first three tests he moved his eyes to the right when he thought of "right", and to the left when he thought of "left". This was the normal expressive movement. In the fourth test, however, the thought "left" was accompanied by an upward movement of the eyes. Two further tests again showed eye-movements to the right and left. In the seventh test with the idea "left" the eyes moved first to the left and then immediately upward. In the following ten tests the eyes were turned regularly upward at the thought of "left", and downward at the thought of "right", with only one exception which was a normal movement to the left. The normal expressive movements, therefore, were displaced by the artificial, after the seventh test.

In the case of another subject (B.) in whom normally the thought of "up"

was accompanied by a slight raising of the head, and "down" by a downward movement, these natural forms of expression disappeared entirely as a result of my arm movements to the right to indicate that I inferred his having in mind the thought of "up", and to the left when I inferred that he was thinking of "down". Instead, there appeared not merely the desired movements to the right and left, but rather movements upward to the right and downward to the left. That is, instead of a complete displacement of the old by the new, there occurred a combination of the two.

A third type of result appeared in still another subject (Ch.), who normally expressed the concepts "right" and "left" by eye or head movements (never both kinds at the same time) to the right and left.

Here my arm movements up and down caused the eye and head movements to be made simultaneously, so that the thought of "right" found expression in an upward movement of the head and an eye movement to the right, and the idea of "left" in a downward head movement and a movement of the eye to the left. The subject had no knowledge of this process, and it took six tests to bring about the new reaction. From that point onward the new movements were so well established that, depending upon them for my cue, I was able to make 32 correct inferences in a total of 40 tests.

During the latter part of this series I blindfolded the subject, so that I could not see the movements of his eyes, and therefore had to base my inference entirely upon his head movements.--After removing the bandage, at the end of the series, I told the subject that I would go through another series, in which I intended to indicate his thought of "right"

by an arm movement downward (instead of upward as heretofore), and his thought of "left" by a movement upward. (This he regarded as an idle whim of mine). It was only after the twelfth test that the former "a.s.sociation" which I myself had caused to be established, was completely displaced by the new. The thought of "right" was now accompanied by an eye movement to the right and instead of a raising there was a lowering of the head. A corresponding change occurred in the head movement expressive of the thought of "left". These responses were occasionally varied by some in which only the head movement or only the eye movement occurred. But these movements were always to the right, or downward and to the right, at the thought of "right",--and to the left, or upward and to the left, at the thought of "left". In ten tests I made ten correct inferences. After the new a.s.sociation appeared firmly established, I ceased responding by means of arm movements, and indicated my 'guesses' by word of mouth. At first the newly acquired movements continued to appear promptly in the subjects. But gradually they tended to become more uncertain and finally disappeared, as readily as they had appeared, and the normal conditions were once more established. Nor was there any tendency to reappear on the following day in another series of tests. (Those just described had been made on one day in the course of an hour or two). But as soon as I again used the earlier method of arm movement to indicate my inferences (raising the arm for "right", lowering it for "left"), the former artificial a.s.sociation was again established, although not until some 14 tests had been made,--during which the normal movements to the right and left were often inhibited and during which the conditions were, on the whole, chaotic. The new a.s.sociation, thus re-established, remained constant during the ten tests of the remainder of the series, but has very probably again disappeared long ere this. In the case of this subject it appears therefore that the new a.s.sociations were superimposed upon, but in no sense displaced, the normal expressive movements. Nor did the two coalesce (except in a few exceptional cases), but tended as a rule to occur independently of one another.

I would emphasize once more that none of the subjects had any knowledge of the purpose or meaning of the experiments. Also, I was convinced by questioning the subjects afterwards that none of them--and this is the essential point--had merely conceived of the arm movement which they were expecting me to make, instead of concentrating thought upon the idea of "right" or "left". On the contrary, all of them considered my particular movements mere vagaries and without purpose, and they felt perfectly certain that they were in no wise influenced by these movements. Also, none of the subjects was conscious of any movements on their part, except one, who was at times aware of her eye movements to the right, but never of those to the left, (see page 111), nor of the head movements which for us const.i.tuted the phenomena of prime interest.

When I asked my subjects what they believed to be the cue upon which I based my inferences, they invariably responded with probable explanations which were always wide of the mark, and those to whom I disclosed the cue--(after the experiments were completed), were thoroughly astonished.

In the tests just described we had to do only with such ideas or concepts as normally were a.s.sociated with some stereotyped form of expressive movement (see page 106). I now chose a group of ideas which are not normally a.s.sociated with a particular form of motor expression peculiarly characteristic of them, and sought to establish artificially such a connection with some arbitrary movement, without consciousness of the process on the part of the subject. Thus I asked one subject (Miss St.), who had no intimation of the aim of the tests, to think of the following words in any order she might choose: "Ibis" (ibis), "Irbis"

(panther), "Kiebitz" (plover) and "Kurbis" (pumpkin). I said that I would react to her thoughts by means of arm movements forward and backward to the right and to the left, respectively. 15 out of 20 tests were successful, without the slightest suspicion on the part of the subject (whose whole attention was concentrated on the word-content), that she was giving me the necessary directives in the form of very minute movements of the head and eyes to the right and left, etc. She was greatly astonished that I should be able to guess words so much alike,--(she did not know that the element of likeness was productive of no difficulty). When, during one of the tests, the subject happened to think spontaneously of the movement she was expecting me to make, she became confused, and as a result the number of my sucessful reactions suddenly fell. I never would have discovered the cause, had not the subject enlightened me without my asking.

I repeated this series with three other persons, who had had some psychological training. I did not use the same movement for each word in all three cases, but indicated the word "Kiebitz", for instance, by means of an upward movement in one case, by turning the head to the right in another, etc. In one of the three cases the tests were almost wholly unsuccessful. The cause for this came to light later, but it would involve too much exposition to discuss it at this point. In the case of the other two persons, the tests were successful beyond expectation. I had made my various arm movements only a few times when they presently began to raise their heads slightly when thinking of "Irbis", and to move it to the right at the thought of "Kurbis", etc. In the two series of 35 tests I did not have a single error. In a number of instances I succeeded in guessing the word upon which the subject had decided, even before the test proper was entered upon--i. e., before the signal for concentration had been given. Nothing surprised a subject more than the remark: "You are intending to think of the word 'Kurbis'", or "You had thought of concentrating your mind upon 'Ibis' but later decided in favor of 'Kiebitz'", yet nothing could be more simple. Before every test the subject would consider what word he would fix upon, and while he was saying to himself "I will choose 'Ibis'", the proper movement would accompany his decision, although it was only very slight, because attention had not yet attained the degree of concentration which was employed in the test proper.

In these experiments also, the subjects, whom I know to be absolutely trustworthy, declared that they never thought of the arm movements which I was to make. They regarded them as being quite irrelevant. Also--with but one exception--they thought of the objects, in so far as they imaged them visually, as being directly before them, and not off in the direction indicated by my arm movements. Thus they did not image the plover ("Kiebitz") as being on the wing, when I raised my arm, or as resting on the ground, when I pointed downward, etc. One of the subjects had done this occasionally, but by no means regularly. He was therefore asked to localize all objects in the same place, i. e., directly in front of him at the level of the eye. He complied with this request, but no change, whatever, was observed to occur in his expressive movements.

In order to overcome the difficulty just mentioned, I selected another subject (Miss von L.), whose power of visualizing was very slight, and requested her to fix her mind upon four words which I had selected because they were not, necessarily, a.s.sociated with a particular image.

The order in which the words were to be thought of, was entirely optional on her part. The words were "Form", "Inhalt", "Ma.s.s", and "Zahl", (form, content, measure, and number), and each of them I accompanied, with a certain definite arm movement. The subject always p.r.o.nounced the word inwardly as emphatically as possible, but without ever imaging the corresponding arm movement. Often, it must be noted, she did not know whether or not the movement which I made was the proper one. And yet she, too, soon fell into line in the matter of executing unconsciously the characteristic head movements. In a total of 50 tests, I was able to make 10 correct guesses in the course of the first 20 tests, 8 in the next 10 tests, and 19 in the last 20 tests. Miss von L.

noted only a few of her upward head-movements, viz.: those that were especially p.r.o.nounced (movements through about 2 millimeters), but of the others she knew nothing. The same experiment was repeated with a psychologist, well-trained in introspection, as a subject. Success was even greater here. But no matter how closely the subject observed himself, he was unable to solve the puzzle.

Variations which were introduced in these tests, I will only mention in pa.s.sing. Thus, instead of making an arm movement, I, in some cases, would tap with my foot, for "Ibis" once, for "Kiebitz" twice. The subject could not see my feet. The involuntary movement-expression which became a.s.sociated with "Ibis" was one nod of the head, with "Kiebitz"

two nods, etc. Here our only concern was to show that unconscious change in natural expressive movements and the acquisition of artificial ones are possible in the case of psychically normal subjects trained in introspection.