LABORATORY TESTS
The tests which are to be briefly reported here, were begun in November,
1904, and were carried out at the Psychological Institute 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
space 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 fashion 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 sex (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
assume 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 pronounced 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
pronounced 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 illustrations 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 pronounced). 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 astonishing 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 coarser sort) to be noted in nearly
every race and people show a great, though by no means complete,
similarity. The similarity is most pronounced 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 assured 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 assertion
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 principally 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 mass 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 assumed, 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
"association" between any given concept and any given expressive
movement. The following experimental series will serve to illustrate
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
fictitious 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
"association" 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 association 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
association 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 association, 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 associations 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 constituted 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 associated with some stereotyped form of
expressive movement (see page 106). I now chose a group of ideas which
are not normally associated 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 "Kuerbis" (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 "Kuerbis", 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 'Kuerbis'",
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, associated 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", "Mass", and
"Zahl", (form, content, measure, and number), and each of them I
accompanied, with a certain definite arm movement. The subject always
pronounced 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 pronounced (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
passing. 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 associated 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.
I was not satisfied with convincing myself subjectively of the facts
indicated, but sought to fix them objectively, by means of a graphic
method. For this purpose I used the device mentioned by Prof. R. Sommer
for the analysis of expressive movements.[18] The purpose for which
Prof. Sommer's apparatus had been constructed, was to record the
involuntary tremor and movement of the hand. These movements, of course,
take place in the three dimensions of space. By means of three levers it
is possible to record the movements upon the flat surface of a smoked
paper fastened to the revolving drum of the kymograph, the movements in
each direction being recorded by a separate lever, in such a way that
the three curves thus made represent the analysis of a single movement
into its three dimensional components. By making slight changes, which
tended to complicate the experiment somewhat, I adapted the apparatus to
the measurement of movements of the head. The method of experimentation
was the following. The subject whose movements were to be registered,
was placed in the device in such a way that his trunk and head were bent
slightly forward, the latter a little more than the former. This, it
will be remembered, was the usual position of the questioner when
working with the horse. Three levers were attached to his head in such a
way that every movement backward or forward would act upon the first
lever, every movement to the right or left would move the second, and
every movement of the head upward or downward would be recorded by the
third. With regard to the sensitivity of the machine, micrometric
determination showed that when the subject was properly installed,
movements through so small a distance as 1/10 millimeter could be
accurately ascertained. The subject was carefully instructed to remain
as quiet as possible, but without constraint. Voluntary movements were
thus obviated. But the question arose: were not the involuntary
movements thus suffering a loss?--And it was upon them that we were
experimenting. The question cannot be put aside summarily, but
experience taught us that the movements in question, nevertheless, did
appear quite effectually, if one could have the right kind of subjects
at one's command. We need hardly mention that besides the two persons
immediately concerned--I, myself, attended to the apparatus--there was
no one else present, and that the subject was not allowed to see the
curves produced on the kymograph. Besides the registration of the
head-movements, I also undertook to register the respiratory-movements
of the subject. This was done by means of the so-called pneumograph,
attached to which was a lever recording the thoracic expansion and
contraction. This was for the purpose of ascertaining the relationship,
which might eventually be found to exist, between the release of psychic
tension, on the one hand, and respiration, on the other.
The subject was now told to think of some number, which, of course, was
unknown to me. At a given moment I was to tap upon one of a series of
keys arranged like those of a piano, with the middle finger of my right
hand--corresponding to the right forefoot of the horse. The questioner
observed my key, I, his head,--just what had happened in the experiments
with Hans,--and as soon as I perceived the involuntary closing signal I
reacted upon it by releasing, suddenly, another key upon the same
keyboard, which I had in the meantime been pressing down with my second
finger, thus marking what with Hans had been called the backstep. Each
key was connected with a separate electro-magnet, and these in turn with
markers, in such a manner that pressure upon the keys closed two
electric circuits and, releasing the keys, opened them, and both the
closing and the opening were recorded upon the smoked paper by means of
the markers. And, finally, in order to ascertain the time relations of
all these processes, a time-marker indicated the time in fifth-seconds
upon the revolving kymograph record. The time-curve was recorded just
below the other curves.
Of the curves[P] thus obtained under the most equable conditions
possible, we publish seven which show the great general uniformity of
the tests made upon the horse with those made in the laboratory. The
role of questioner was undertaken at different times by Mr. Schillings
and the students of philosophy, Messrs. von Allesch, Chaym and K. Zoege
von Manteuffel. To all of them I am greatly indebted for their unselfish
services in these laborious tests. The experiments with von Allesch and
Chaym, who were among the most suitable of my subjects, were conducted
absolutely without knowledge on their part of the nature of the
phenomena which I was observing. Neither of them knew anything about the
expressive movements in which they were unconsciously indulging, and
furthermore, since they kept their heads bowed during the entire course
of these experiments, they did not perceive what it was that I was
observing. It is interesting to note that Chaym on the occasion of his
only visit to the horse, immediately received a number of correct
responses. Without a doubt von Allesch would have met with equal
success. The other two subjects (von M. and Sch.) went through this
series of tests, possessing some knowledge of the nature of the
movements involved. Conditions were such that they (and especially Mr.
Schillings) could not be prevented from obtaining some knowledge of the
essentials, at least. However, it would be wrong to suppose that for
this reason the results were more favorable, owing, mayhap, to voluntary
efforts on the part of the subject. The contrary was true. The two
subjects who had no knowledge of the character of the reactions upon
which my responses depended, retained their normal habits, unchanged,
throughout the series,--whereas the last-named two, afraid lest their
knowledge vitiate the result, lost more and more of their power of
concentration and within a short time were in a condition of tense
inhibition, which is all the more conceivable, since they had had no
psychological training whatever.[Q]
[Footnote P: For registering the curves a Hering kymograph was used,
with a loop 2-1/2 metres long. The kymograph rested on felt. With
the aid of the Marey model a pneumographic record was taken now of
the thoracic, now of the abdominal, breathing, never both
simultaneously, since this was extrinsic to my purpose, and it would
have made the whole experiment too complex. The time was recorded by
means of the Jacquet chronograph. For purposes of making more exact
measurements the acoustic current interrupter of Bernstein was used,
attuned to 100 vibrations per second. But this necessitated such
rapid revolution of the drum of the kymograph that the curves were
not compact enough for purposes of demonstration. The levers were
all fitted with micrometer adjustments. They wrote tangentially and,
except the one registering the breathing curve, all points lay in
one vertical line. The error of deflection and that due to the
rondure of the writing-surface were both very slight on account of
the comparative length of the levers and the small extent of the
excursions, and for that reason synchronous points lie practically
in one perpendicular. Only the breathing curve has been moved
somewhat to the left, 7.5 millimeters in figures 6 and 7, 2
millimeters in figure 8, 4.5 millimeters in figure 9. (When the
breathing was very profound, as occasionally happened, the error of
deflection would, of course, have to be taken into account.) The
curves here used as illustrations have been reproduced in the exact
size of the originals by the zinco-graphic method, though somewhat
compressed vertically in order to economize space.]
[Footnote Q: My own expressive movements, on the other hand, are as
pronounced as ever. I still find the attempt to suppress them as
difficult now as when I was working with the horse (page 57). I
could not, of course, procure a curve of these movements of my own.]
Their movements, which at first were quite profuse, decreased more and
more, so that in the case of von Manteuffel the percentage of my
successful responses sank from 73% correct responses in 90 tests to 20%
in a total of 20 tests,--and in the case of Schillings from 75-100% to
23% in a series of 35 tests. The curves obtained with von Manteuffel as
subject, which I am here publishing (figures 8 and 15), are, however,
true to his normal habits. The same is true of the two first curves of
Schillings (figures 10 and 11), whereas the third (figure 12) shows
distinctly the traces of the state of inhibition into which he fell, and
represents the same condition as when Mr. Schillings, while preoccupied,
tried to work with Hans. All the finer details of the phenomena in
question, were likewise unknown to these two subjects.
For purposes of a clearer understanding of the various curves, figure 5
is inserted to give the general scheme of their arrangement.
[Illustration: FIG. 5.]
All curves are to be read like script from left to right. The first is
the breathing curve of the questioner, the second, third and fourth
curves represent his head movements,--all translated through the
workings of the levers into up-and-down movements. The objective
direction of these head movements is indicated by the arrows. It will be
noted that (because the lever in question was one with two arms, and
therefore reverses all movements made) each lowering of the head is
indicated by a rise in the fourth curve, and each raising of the head is
recorded by a sinking in the same curve. The records of the head
movements forward and backward and to the left and right (curves 2 and
3) are two and one-half times the size of the actual movements; while
the curve of the movements up and down (curve 4)--which is of especial
interest to us--is five times its actual size. The fifth and sixth
curves, which record my own responses, represent the taps of the
horse,--the fifth indicating the number of taps and the sixth the
back-step, which was Hans's reaction when he noted the head-jerk of the
questioner. The seventh, the lowest line, indicates the time in
fifth-seconds. Since the rate at which the drum revolved was not uniform
for all the tests, the fifth-second marks do not appear the same
distance apart in all the records, but are farther apart the greater the
rapidity with which the drum revolved. For the experiment itself this is
quite immaterial. Figures 6 to 9 correspond in detail with the diagram
just described. Figures 10 to 12 differ only in that the breathing and
back-step curves (the first and sixth in the diagram) are lacking. In
these there is no response on my part to the head-jerk of the subject,
but tapping was continued _ad libitum_ (in the case of the illustrations
here given I tapped to 5). When these latter curves were taken the
ordering and the technique of the experiments had not yet been
perfected. When this was finally done, Mr. Schillings, who acted as
subject in those tests, had to be eliminated from the ranks of
appropriate subjects on account of the increasing inhibitions, which
gradually developed as described on page 120.
Analysis of such curves is rather difficult, and those of different
subjects cannot be directly compared. It is necessary to make a study of
the normal curve of each subject taken when his affective state could be
described as "indifferent". The influences of the purely physiological
processes, such as pulse[R] and respiration, must also be determined.
And even so, an interpretation of the curve becomes possible only when a
large mass of material is at hand, and when the introspections of the
subject are taken into consideration. The following remarks, therefore,
are not based solely upon the illustrations given, but upon the mass
total of my results.
[Footnote R: Slight head movements accompanying the pulse-beat were
until recently regarded as the symptom of certain diseases of the
vascular system (the so-called symptom of Nusset), but H. Frenkel
has now shown them to exist also in normal individuals.[19] I myself
discovered such movements (lateral as well as sagittal) more or less
pronounced in all the curves obtained from my subjects. The most
striking case was that of a young physician whose circulatory system
was perfectly healthy. In most instances I was able to note these
oscillatory movements directly and to count them without much
difficulty. For purposes of control the radial pulse was always
determined at the same time. The observation of the phenomenon
appears to be especially easy in the case of somewhat full-blooded
individuals.]
In beginning our analysis, let us take first the breathing curve. Our
results here were quite in accord with the view taken by Zoneff and
Meumann,[20] who believe that in the respiration is to be found a good
index of the affective tone of the subject's mental state. In the
greater number of cases it was possible to conclude as to the degree of
concentration of attention,--and when this was very great, it was even
possible to get a clue as to the number thought of. Since the high
degree of tension, under which a subject labored during a test, would be
accompanied by strong affective coloring, we cannot regard as normal any
of the curves here reproduced (with the exception of the two high points
in figure 9). Although breathing was always deep and regular before and
after a test, during the test it was less deep and irregular. Very often
it was suspended altogether (figures 7, 8 and 9). In ordinary life we
often notice that highly concentrated attention is usually accompanied
by non-voluntary inhibition of movements in the musculature which, for
the moment, is not directly involved; the man lost in thought slackens
his pace and finally stands still, the intent listener or looker-on
holds his breath.
Of the three curves registering the movements of the head, we find that
nothing peculiarly characteristic is revealed by the two upper ones,
giving the movements up and down, and to the right and left,
respectively. They are the ordinary tremor-like movements and indicate
nothing beyond the fact that the subject is unable to hold his head
absolutely quiet for even one second. It is the third line that is of
interest to us, for it is here that the oft-mentioned head-jerk (which
indicates arrival--in the counting--at the number expected) registers
itself. The moment of the head-jerk corresponds, almost without
exception, with the moment of the first deep inhalation,--just as one
would be led to expect from common experience. But we are not to regard
the head-jerk as a result of the inhalation, for it also occurs when the
subject complies with the request that he hold his breath during the
test. The actual height of the jerks recorded in figures 6 to 12 was
1/4 to 1-1/2 millimeters and the average height obtained from the forty
curves of these four subjects was 1 millimeter. There is great
individual variation: the greatest height that was obtained from the
records was 2-3/10 millimeters, the lowest 1/10 millimeter. The
variations within the records of the several individuals are
comparatively slight and are evidently dependent, in the main, upon the
degree of concentration of attention. Thus in the case of von Allesch,
where in 75 tests the average height of the jerk is 1 millimeter, the
mean variation is 4/10 millimeter. If, in order to obtain some idea of
the size of Mr. von Osten's movements,[S] we compared the values gained
in the laboratory with those which would probably obtain in his case, we
would say that his head movements were more minute than almost any of
those of which we obtained records. At the most they could not have been
more than 1/5 millimeter (when measured in terms of the distance through
which the brim of his broad hat moved, they would appear to be about
1-1/2 times as large. See page 49.) The movements of Mr. Schillings, on
the other hand, were certainly four or five times as great as those of
Mr. von Osten, and occasionally even greater than that. When we turn to
consider the time-interval elapsing between the subject's final
head-jerk and my reaction (as recorded in the sixth curve), we find
that the reaction-time averages 3/10 seconds, a value which agrees very
favorably with that estimated for the horse (page 56). Thus it appears
that man and beast have the same reaction-time--though we must bear in
mind that I worked under some difficulty, since I had to care for the
apparatus.
[Footnote S: In a special series of experiments a subject was
instructed to execute rapid head movements as minute and as evenly
as possible. These were registered objectively and at the same time
I made judgments concerning them. The results showed that my
judgments were most exact in the case of the most minute jerks. The
thing that made it especially easy to judge the movements of Mr. von
Osten under normal conditions, (page 220), was their extraordinary
evenness, such as I have not met with in any other individual.]
Let us now turn to a discussion of the several figures.
Figure 6 (von Allesch) gives a typical view of the great, and at the
same time economic concentration of attention characteristic of the
subject. Respiration (first curve) is not so profound as usual, yet is
changed very little. The head-jerk (fourth curve) is of medium height.
It occurs just at the proper moment,--the subject had thought of 2, and
had directed his attention economically. This attention was of the kind
described as type I on page 93. The lowering of the head, (recorded in
the figure by a rise in the curve), immediately following upon the
head-jerk upward, is irrelevant.
In figure 7 (Chaym) we have a record of a different nature. Respiration
was inhibited throughout the test,--(the small waves are due to the
pulsating of the heart); immediately after the test deep breathing takes
place. Tension steadily increased till 3, the number expected, was
reached. The head, accordingly, gradually sank a little forward. The
head-jerk ensued during an interval beginning just before the reaching
of the goal and ended immediately after. The movement was predominantly
backward, its upward direction being only through a distance of 1/4
millimeter. (This subject was not so strongly motor as the preceding
one.) The reaction followed promptly as seen in curve 6. It was the
decided raising of the head which follows the head-jerk, that prevented
the usual back-step with the left foot, when the subject was working
with Hans.
[Illustration: FIG. 6.]
[Illustration: FIG. 7.]
Figure 8 (von Manteuffel) is typical of strong and at the same time
economical concentration. Respiration, normally deep and very regular,
is for a time completely inhibited. Tension rises steadily and the head
gradually inclines forward. In the interval between the number before
the final one and the final one the subject makes a sudden bend forward
and immediately upon reaching the final number gives a violent jerk of
the head, upward. The attention here would be characterized as being of
type III, described on page 94. (Owing to lack of space it is impossible
to give an example of type II, which is only to be found in the case of
very large numbers.)
Figure 9 (von Allesch) is expressive of great, but--according to the
subject's introspection--not economical concentration. Respiration,
which before and after the test was quite regular, during the test
itself shows a pause. (The tiny waves are due to the heart-beat.) The
subject had thought of 5, and this number is accompanied by a decided
head-jerk. But we note that even before the final jerk a number of less
pronounced jerks occur--the result of poorly regulated psychic tension.
[Illustration: FIG. 8.]
[Illustration: FIG. 9.]
Figure 10 (Schillings) depicts a very high degree of uneconomical
concentration. There was sudden concentration at the beginning of the
test, and a steady increase throughout its course. Accordingly Mr.
Schillings bent forward at the start, and inclined still farther
forward at the second--and just before the third--tap. But at 3 there is
a sudden upward jerk. The number thought of had been 4, tension
therefore had exploded, as it were, too soon.
[Illustration: FIG. 10.]
Figure 11 (again of Schillings) gives indications, on the other hand, of
a medium and economic concentration of attention, which is more normal
in character. The number thought of was 4.
[Illustration: FIG. 11.]
Figure 12 (Schillings again) is indicative of a low degree of psychic
tension. With the very first tap the head begins to rise and continues
to do so throughout the test. A true final jerk does not occur, we note
rather in all three curves registering the head movements, slight
time-marking movements, especially in the second curve. In the third
curve they are at first minute, but increase steadily in size until the
fourth tap, after which they suddenly disappear. The subject had, as a
matter of fact, thought of the number 4, but it is hardly probable that
Hans would have reacted properly upon these stimuli.
[Illustration: FIG. 12.]
Mr. Schillings had thought of the same number in all three tests given
in figures 10, 11 and 12. The probabilities are that if he had been
working with the horse at the time, in the first case Hans would have
reacted with three taps with the right foot and a final tap with the
left, as a result of the questioner's bending forward again after the
premature head-jerk at 3. In the second instance the horse would
probably have given four taps with the right foot, and in the third, the
chances are that he would have continued to tap beyond the 4.
These curves give, on the whole, a fair idea of the intensity and of the
course of attention of the various subjects.
Let us now consider a number of records which illustrate the expressive
movements involved in the process of thinking of such concepts as "up",
"down", etc. Their arrangement is identical with the scheme given in
figure 5, with the exception that the tapping curves (the sixth and
seventh) do not appear. The subject was asked to think of any of the
words "up", "down", "right", "left", "yes", "no", etc. He was to begin
to conceive them vividly when the command "Now!" was given. This moment
is recorded in figures 13 to 15 on the fifth curve. What has been said
on page 123 with regard to respiration, holds also in these instances:
only the first rise recorded in figure 14 can be regarded as normal.
The magnitude of these movements varies between 1/2 and 3 millimeters.
The records of the subject whose movements were most extensive, show an
average of 1-7/10 millimeter (based on 50 tests), with a mean variation
of 6/10 millimeter. Lack of space precludes the reproduction of more
than three records.
Figure 13 (von Allesch) shows the movement accompanying the thought of
"up", a slight raise of the head, recorded in the fourth curve. (The
thought of "down" is accompanied by a corresponding downward movement.)
[Illustration: FIG. 13.]
Figures 14 (von Allesch) and 15 (von Manteuffel) illustrate the nod
which is associated with the thought of "yes" in the case of two
subjects. It is essentially the same in both: the head is lowered and
then raised. The first of the two subjects is more decidedly motor, and
his movements therefore were somewhat the more extensive. In the case of
the second subject the nod proper is followed by another which is
somewhat less extensive.
[Illustration: FIG. 14.]
[Illustration: FIG. 15.]
A number of other experiments were carried out which corresponded with
the color-selecting tests made upon Hans. (Page 78.) Five sheets of
white paper, 1/2 meter long and 1/4 meter wide, were arranged in a
series upon the floor, 1/4 meter apart. A dot marked the middle of each.
The experimenter stood at a distance of 7-1/2 meters and directly
opposite the middle sheet. At about 1/2 meter to the right or left of
him stood the subject who took the part of the "horse". The problem of
the experimenter was to indicate to the "horse" a certain one of the
five sheets, but without the use of word or gesture. I at first
undertook the role of "horse", whereas the others consecutively played
the part of questioner. All of them looked fixedly at the sheet which
they had in mind. Besides, it usually happened that they would turn at
least their heads, and often their bodies, more or less in the direction
of the particular sheet--and this without purpose or knowledge on their
part, but purely as a result of concentration upon the sheet they wished
me to point out. One of the experimenters remarked, quite casually,
that he had noted that I always made a better judgment, the more
intently he thought of the sheet. Others often admitted that, when I had
made an error, they had not imagined the sheet vividly, or had been
debating whether or not to decide to think of the neighboring sheet--the
one I had designated. This indecision could be noticed by the direction
of the eyes. But the following table shows how uniform, on the whole,
was the behavior of the various persons when under the guidance of the
same impulse. The number of tests was 200 in each case. All errors were
of the same character. Neighboring sheets were mistaken for each other,
and the errors were never of more than one position to either side.
Their number can easily be obtained by subtracting the percentage of
correct inferences from the total, 100%.
Experimenter: v. A. B. C. Mrs. v. H. K. Miss v. L.
Correct inferences: 88% 88% 77% 81% 77% 82%
It will be seen that the number of correct interpretations is quite high
and in none of the cases does it deviate far from the mean average of
82%.
I based my judgment as to the direction of the subject's eyes, upon an
imaginary line perpendicular to the center of the cornea. (This
perpendicular does not always coincide with the subject's line of
vision, which was the thing I was after, but this cannot be directly
obtained. This, of course, was what made the judgment a rather difficult
matter.) My judgment as to the direction of the head I based largely on
the direction of the nose, (to express it more accurately: upon the
direction of the median plane.) I purposely noted only the position of
the experimenter and not the movement which led up to it. When I tried
to do the latter, the results were not always satisfactory, because the
head and eyes of the person would frequently, in the process of
adjustment, move beyond the goal and thus lead me into error. An attempt
was made to make each judgment as independent as possible of the
preceding one. But usually, after a few tests, an unintentional
association became established between certain attitudes and the
different places in the series of papers. Often all that was necessary
was to observe the experimenter in order to know which of the places he
had in mind, it was not necessary to look at the papers at all. Every
change in the position of the person would, of course, make the
association thus established, useless.
Later, the subjects and I changed roles, I took the part of the
experimenter and they the part of the "horse". The number of tests in
each case was 200 as before. Here, too, errors were, with but one
exception, never more than of one place to either side. Whether the
error was one place to the right or one place to the left appeared to
depend upon the position of the person making the judgment, i. e., it
depended on whether he stood at my right or at my left. The following
results were obtained:
Subject ("horse"): v. A. B. C. Mrs. v. H. K. Miss v. L.
Correct inferences: 76% 79% 75% 81% 77% 74%
A certain agreement can be seen in these results. The average of correct
inferences is somewhat lower than that which was obtained by me (page
135), 77% as over against 82%. This is probably due to the fact that the
subjects had had so little practice compared with me.
With one of these subjects, Mr. Koffka, a student of philosophy, I
carried these tests somewhat further, varying them partly by increasing
the number of sheets of paper, partly by decreasing the distance between
them. The increase in the number of sheets made only a slight difference
in the results. With 200 tests in each case I obtained the following
results:
No. of sheets : 5 6 7 8 9 10
Correct inferences: 77% 72% 72% 69% 73% 68%
With but few exceptions, the errors were, as a rule, of one place. The
series with an odd number of sheets (5, 7, 9) gave better results than
those with an even number (6, 8, 10). In the tests with the odd number
of sheets the experimenter (K.) stood in front of the middle sheet, so
that it was at the apex of a right angle made by the series of papers
and the median plane of the subject's body; whereas in the case of the
even number of papers the subject stood opposite the space between the
two middle sheets, thus making the position of the sheets less
favorable.
In the preceding tests the distance between the centers of the
neighboring sheets was always 50 centimeters, so that the angle through
which the median plane of the experimenter's body would have to turn in
order to pass from one sheet to the next, was about 3-3/4 degrees. In
the following tests these distances were gradually decreased. The
sheets, always five in number, were replaced by ever narrower white
strips of paper mounted on dark cardboard and illumined by a Nernst
lamp. The following table shows the decrease in correct inferences
running parallel with the decrease of the angle through which the
subject would have to turn in order to be in line with the several
pieces of a series successively. The percentage in each case is based
upon at least 100 tests.
Angle: 3-3/4 deg. 3 deg. 2-1/2 deg. 2 deg. 1-1/2 deg. 1 deg.
Distance between the
centres of two neighboring
papers: 50cm. 39cm. 33cm. 26cm. 20cm. 13cm.
No. of correct inferences: 77% 73% 71% 68% 66% 61%
A curious and unexpected change was here noted in the subject, Mr.
Koffka, who, while concentrating his attention to the uttermost, began
unawares to develop a new system of expressive movements of the head.
When the distance between the sheets was relatively great, he had been
in the habit of turning his head and eyes in the direction of the sheet
intended, and as the distances became less he had reacted only by a
turning of the eyes. But now, as the distances were still further
decreased, he began again to react by means of head movements, and these
were of exaggerated magnitude, for which he would compensate, as it
were, by an eye-movement in the opposite direction. Although the head
movements decreased in scope as the distances between the sheets were
steadily decreased, they still were always decidedly greater than the
eye movements, which I was now normally led to expect and which could be
judged without much difficulty. This form of reaction was much more
satisfactory as a cue, and therefore it came to pass that, whereas in
the preceding series I had made only 60% correct inferences when the
angle was 1 degree, I now found that--the angle remaining the same--80%
of my inferences were correct. (My final judgment I continued to base,
as before, upon the position, and not upon the movement, of head and
eye). The number of correct inferences continued relatively high, even
after the distance between the papers was decreased tenfold,--as will be
seen from the following table:
Angle: 1 deg. 30' 15' 9' 7' 6' 5' 3' 2'
Distance between the
centres of two neighboring
papers: 131 65 33 20 15 13 11 6-1/2 4mm.
Percentage of correct
inferences: 80 79 78 81 84 80 77 68 68%
Beginning with an angle of 1' (distance between the centers of two
neighboring papers = 2 mm.), the subject was unable to focus, with
sufficient steadiness of vision, upon one paper alone, and the
movements, for that reason, ceased to manifest themselves. Comparing the
results obtained in the case of this subject with those obtained from
two others, whose reactions had remained normal, B. and Miss St., we
find that with them there were only 53% correct inferences in both cases
(based each upon 200 tests), when the angle was 5'. In my errors, too, I
often shot wider of the mark. In another series of 200 tests, in which
Miss St. "merely thought of the places", I had a percentage of 56%
correct inferences, and my errors did not become any coarser. Miss St.
believed this a case of true telepathy, but I had been guided in my
judgments entirely by her unwittingly made movements--or rather the
direction--of her eyes. The magnitude of these movements bore a constant
relationship to the distance between papers as it was conceived by the
subject.
Reviewing the experiments discussed in this chapter, we find that the
same kind of movements and postures, which had been noted in persons
experimenting with the horse, tended to recur in the laboratory, in so
far as the mental attitude of the subjects, given in their introspective
accounts, corresponded with that of the questioners of the horse.