THE AUTHOR'S INTROSPECTIONS
In the preceding chapter we asked: What is it that determines the
horse's movements? Independent thinking, or external signs?--We found
that it was solely external signs, which we described as certain
postures and movements of the questioner. Beyond a doubt these necessary
signs were given involuntarily by all the persons involved and without
any knowledge on their part that they were giving any such signs. This
is to be seen from their statements, which cannot be cavilled at, as
well as from the fact that several of them even to-day still doubt the
correctness of the explanation which we are here offering. I myself for
some time made these involuntary movements quite unwittingly and even
after I had discovered the nature of these movements and had thus become
enabled to call forth at will all the various responses on the part of
the horse, I still succeeded in giving the signs in the earlier naive
involuntary manner. It is not easy, to be sure, to eliminate at once the
influence of knowledge and to focus attention with the greatest amount
of concentration on the number desired, rather than upon the movement
which leads to a successful reaction on the part of the horse. To some
this may appear impossible, but those who are accustomed to do work in
psychological experimentation, will not deny the possibility of such
exclusive concentration upon certain ideas.
If we now ask: "What occurred in the mind of the questioners, while they
were giving the signs?", the answer can be found only by way of the
process which in psychology is technically called "introspection", i. e.
observation of self. In the following we will give the most important
results of this process of self-observation, which took place in the
same period in which the observations recorded in the preceding chapter
were made.
My first experiments were made while the horse was counting or solving
arithmetical problems and were as follows: Mr. Schillings, who was alone
with me in the horse's barn, asked me to think of several numbers,
maintaining that the horse would be able to indicate them correctly upon
being asked. He stood to the right of the horse, I stood erect and at
the side of Mr. Schillings. There was no one else present. Somewhat
skeptical in attitude, I concentrated my mind consecutively on five
small numbers. Hans tapped one of them incorrectly, one correctly and
three by one unit too many. At the time I considered these attempts as
unsuccessful and credited some curious chance with the answers which
were correct, or nearly so. This was a mistake, for often during the
following days, and in the absence of Mr. von Osten, the horse would
give correct answers. Others, of course, would be incorrect, and usually
the mistakes would be by one unit,--so that I soon saw that even in the
horse's errors there lay some system. It will be seen that Hans
responded to me from the very beginning, undoubtedly because I had had
the opportunity of watching Mr. von Osten and Mr. Schillings and had
thus patterned my behavior after theirs. I was not at first successful
in getting the horse to respond correctly in the case of large numbers.
For in order to get complete control over the horse, and, what was, as
I later discovered, more to the point, control of myself, some practice
was needed. But I was able to work with the horse quite successfully,
while I was still in the dark as to my own behavior.
From the very beginning Hans responded as promptly to those questions
which I articulated merely inwardly, as to those which were spoken
aloud. That all formulation of the question was unnecessary, however,
was shown by the following experiments. If, for example, I did not think
of any particular number until after the horse had begun to tap, and
then fixed upon 5, he would tap 5. If, however, I told him to count to
6, but gave no further thought to the command after he had begun
tapping, I would get an entirely wrong response. It was easy to obtain
any answer one wished to a question, simply by focussing consciousness,
with a great degree of intensity, upon the answer desired. Thus Hans
answered my question: "How many angles has a hexagon?", first by 6, then
2, then 27, in accordance with the numbers that came into my mind. The
animal always followed the ideas which were in the questioner's mind,
and never his words, for it was with the former that the movements upon
which the horse depended were bound up.
It was not enough, however, simply to imagine the number desired. It was
furthermore necessary that the questioner be conscious of the moment
when the horse reached that number. Larger numbers (above 6) were
therefore, successful only when every single tap was inwardly counted to
the end. The manner of counting was indifferent. Thus I counted 6 as
follows: 1, 2, 3, 4, 5, 6, and later: 6, 5, 4, 3, 2, 1, and then again:
6, 6, 6, 6, 6, 6. Finally I used the Greek letters and also nonsense
syllables. And in all cases I obtained six taps, the correct response.
If, however, I simply counted the taps without knowing when the desired
number was reached, the responses were always incorrect, e. g., I
counted
For No. 10: 10, 10, 10 continuously, Hans tapped 13,
" " 10: 1, 2, 3 to 10 " " 10,
" " 12: 12, 12, 12 continuously, " " 15,
" " 12: 1, 2, 3 to 12 " " 12.
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 passive 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 repetition 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
fashion, 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 assume.
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 passing
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 assumption 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 retardation, 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 pronounced 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 space, 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 pronounced 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 associated
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 attitude here was still the same as
when I put the question aloud. What sort of an attitude 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 assumed, 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 anticipatory 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 associated 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 assume 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 assumed 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 pronounced 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 prone 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.