Etext of On the Witness Stand Essays on Psychology and Crime
by Hugo Mnsterberg

Foreword (by Charles S. Whitman)
Introduction
Illusions
The Memory of the Witness
The Detection of Crime
The Traces of Emotion
Untrue confessions
Suggestions in Court
Hypnotism and Crime
The Prevention of Crime  

On the Witness Stand:
Essays on Psychology and Crime
Hugo Mnsterberg

FOREWORD

THE administration of justice is susceptible of division into two
general branches: one having to do with the determination of the
facts, the other, with the application to the determined facts of
legal precepts. 

The facilities of administration in the jural held have reached a
state of high development. In the class-room and the seminar, the
attention of the student of law is concentrated upon mastery of
legal principles as applied to determined facts; he is educated in
legal bibliography and precedent. In practice, legal erudition earns
signal commendation and oft-times lucrative reward.

Legal principles have been formulated into rules, doctrines, and
statutes, and have been harmonized and codified. The legal
practitioner, therefore, usually approaches his task proficient in the
knowledge of legal science.

But there is the other branch of the administration of justice which
is no less important than the jural. It has to do with the domain of
facts which holds the dramatic episodes of every controversy
between man and man or man and state. For the tasks here the
lawyer is not usually well prepared. The ability to discern the facts
which control the application of legal principles is not
methodically developed. The education and training of a lawyer
for eliciting the facts are more or less adventitious.

The difficulties experienced by judges, juries, and lawyers in
probing for the truth where conflicting versions are presented are
in no small measure responsible for the cynical attitude which is
general toward the administration of justice. The effort is often
made to overcome contradictory testimony of witnesses, in
forensic contest, by crimination and recrimination. Such methods
inspire no confidence in the resulting judgment, but produce
distrust toward administrative and judicial processes.

Professor Hugo Mnsterberg, in this book "On the Witness Stand,"
in which is collected a series of magazine articles previously
published by him, pointed the way to rational and scientific means
for probing facts attested by human witnesses, by the application
of Experimental Psychology to the administration of law.
Psychology had been classified as a pure science. Experimental
methods, to the development of which Mnsterberg,[sic] made
notable contribution, have lifted this branch of knowledge into the
classification of applied sciences. Applied Psychology can be
employed in various fields of practical life -- education, medicine,
art, economics, and law. Experience has demonstrated that "certain
chapters of Applied Psychology" are sources of help and strength
for workers in various practical fields, but, says Professor
Mnsterberg -- "The lawyer alone is obdurate. The lawyer and the
judge and the juryman are sure that they do not need the
experimental psychologist . . . They go on thinking that their legal
instinct and their common sense supplies them with all that is
needed and somewhat more . . . Just in the line of the law it
therefore seems necessary not to rely simply on the technical
statements of scholarly treatises, but to carry the discussion in the
most popular form possible before the wider tribunal of the
general reader."

With that aim in mind the author wrote the popular sketches which
are republished in this volume, in which he selected "only a few of
the problems in which psychology and law came in contact."

Professor Mnsterberg was a prolific writer on philosophic and
psychological themes. He was a member of a famous group of
educators who were associated with Harvard University. In his
field, he was a deep scholar and a thorough and intensive
researcher. He delighted in the extension of his educational work,
and in elucidating the technique of his scientific studies for easy
comprehension by lay minds. He had a fascinating style of writing. 

In the work which is now republished, Professor Mnsterberg
furnished an instructive exposition of what may "legal
psychology." Although the articles were first published about
fourteen years ago, they have lost none of their timeliness, interest,
or helpfulness. They introduce the reader to the subject of
psychology as a science; and they contain lessons in experimental
psychology which are invaluable to any one interested in the
administration of justice. The book should stimulate an interest in
the study of this branch of knowledge, which should form an
important and essential adjunct of the equipment of every
investigator and trier of fact, and should encourage the application
of this science to practical use in testing the truth or accuracy of
historical narrative by witnesses.

Dated, New York City, December 15, 1922.
CHALRLES S. WHITMAN
[Ex-Governor of New York
Former District Attorney of New York County]

INTRODUCTION

THERE are about fifty psychological laboratories in the United
States alone. The average educated man has hitherto not noticed
this. If he chances to hear of such places, he fancies that they serve
for mental healing, or telepathic mysteries, or spiritistic
performances. What else can a laboratory have to do with the
mind? Has not the soul been for two thousand years the domain of
the philosopher? What has psychology to do with electric batteries
and intricate machines? Too often have I read such questions in
the faces of visiting friends who came to the Harvard
Psychological Laboratory in Emerson Hall and found, with
surprise, twenty-seven rooms overspun with electric wires and
filled with chronoscopes and kymographs and tachistoscopes and
ergographs, and a mechanic busy at his work.

The development of this new science could remain unnoticed
because it was such a rapid one, surprising in its extent even to
those who started [p. 4] it. When, as a young student, I went to the
University of Leipzig in the eighties of the last century, the little
psychological laboratory there, founded by Professor Wundt, was
still the only one in the world. No Western country college would
to-day be satisfied with those poor little rooms in which the master
of the craft made his experiments with his few students. But since
that time the Leipzig workshop has been steadily growing, and
every year has seen the foundation of new institutes by the pupils
of Wundt, and later by their pupils. The first German laboratory
outside of Leipzig was the one which I founded in Freiburg just
twenty years ago. At about the same time Stanley Hall and Cattell
brought the work from Leipzig over the ocean. Today there exists
hardly a university which has not opened a workshop for this
youngest of the natural sciences.

But more brilliant than the external expansion has been the inner
growth. If the new science started in poor quarters, it was still
more modest at the beginning in its outlook toward the work.
Experimental psychology did not even start with [p. 5]
experiments of its own; it rather took its problems at first from the
neighbouring sciences. There was the physiologist or the physician
who made careful experiments on the functions of the eye and the
ear and the skin and the muscles, and who got in this way
somewhat as by-products interesting experimental results on
seeing and hearing and touching and acting; and yet all these
by-products evidently had psychological importance. Or there was
the physicist who had to make experiments to find out how far our
human senses can furnish us an exact knowledge of the outer
world; and again his results could not but be of importance for the
psychology of perception. Or there was perhaps the astronomer
who was bothered with his "personal equation," as he was alarmed
to find that it took different astronomers different times to register
the passing of a star. The astronomers had, therefore, in the
interest of their calculations, to make experiments to find out with
what rapidity an impression is noticed and reacted upon. But this
again was an experimental result which evidently concerned, first
of all, the student of mental life.

[p. 6] In this way all kinds of scientists who cared little for
psychology had gathered the most various psychological results
with experimental methods, and the psychologists saw that they
could not afford to ignore such results of natural science. It would
not do to go on claiming, for instance, that thought is quick as
lightning when the experiments of the astronomers had proved that
even the simplest mental act is a slow process, the time of which
can be measured. Experimental ,psychology, therefore, started
with an effort to repeat on its own account and from its own point
of view those researches which others had performed. But it
seemed evident that this kind of work would never yield more than
some little facts in the periphery of mental life -- borderland facts
between mind and body. No one dreamed of the possibility of
carrying such experimental method to the higher problems of inner
life which seemed the exclusive region of the philosophising
psychologist. But as soon as experimental psychology began to
work in its own workshops, it was most natural to carry the new
method persistently to new and ever new groups of problems. The
tools [p. 7] of experiment were now systematically used for the
study of memory and the connection of ideas, then of attention and
of imagination, of space perception and time sense; slowly they
became directed to the problems of feeling and emotion, of
impulse and volition, of imitation and reasoning. Groups of mental
functions which yesterday seemed beyond the reach of
experimental laboratory methods, to-day appear quite accessible. It
may be said that there is now hardly a corner of mental life into
which experimental psychology has not thrown its searchlight. It
may seem strange that this whole wonderful development should
have gone on in complete detachment from the problems of
practical life. Considering that perception and memory, feeling
and emotion, attention and volition, and so on, are the chief factors
of our daily life, entering into every one of our enjoyments and
duties, experiences and professions, it seems astonishing that no
path led from the seclusion of the psychological workshop to the
market-place of the world.

Of course this separation was no disadvantage [p. 8] to
psychology. It is never a gain when a science begins too early to
look aside to practical needs. The longer a discipline can develop
itself under the single influence, the search for pure truth, the more
solid will be its foundations. But now experimental psychology has
reached a stage at which it seems natural and sound to give
attention also to its possible service for the practical needs of life.

This must not be misunderstood. To make psychology serviceable
cannot mean simply to pick up some bits of theoretical psychology
and to throw them down before the public. Just this has sometimes
been done by amateurish hands and with disastrous results.
Undigested psychological knowledge has been in the past
recklessly forced on helpless schoolteachers, and in educational
meetings the blackboards were at one time filled with drawings of
ganglion cells and tables of reaction-times. No warning against
such "yellow psychology" can be serious enough. 

If experimental psychology is to enter into its period of practical
service, it cannot be a question of simply using the ready-made
results for ends [p. 9] which were not in view during the
experiments. What is needed is to adjust research to the practical
problems themselves and thus, for instance, when education is in
question, to start psychological experiments directly from
educational problems. Applied Psychology will then become an
independent experimental science which stands related to the
ordinary experimental psychology as engineering to physics. 

The time for such Applied Psychology is surely near, and work has
been started from most various sides. Those fields of practical life
which come first in question may be said to be education,
medicine, art, economics, and law. The educator will certainly not
resist the suggestion that systematic experiments on memory or
attention, for instance, can be useful for his pedagogical efforts.
The physician to-day doubts still less that he can be aided in the
understanding of nervous and mental diseases, or in the
understanding of pain and of mental factors in treatment, by the
psychological studies of the laboratory. It is also not difficult to
convince the artist that his instinctive creation may well be
supplemented by the psychologist's [p. 10] study of colour and
form, of rhythm and harmony, of suggestion and aesthetic
emotion. And even the business world begins to understand that
the effectiveness of economic life depends in a thousand forms on
factors for which the student of psychology is a real specialist. His
experiments can indicate best how the energies of mill-hands can
reach the best results, and how advertisements ought to be shaped,
and what belongs to ideal salesmanship. And experience shows
that the politician who wants to know and to master minds, the
naturalist who needs to use his mind in the service of discovery,
the officer who wants to keep up discipline, and the minister who
wants to open minds to inspiration -- all are ready to see that
certain chapters of Applied Psychology are sources of help and
strength for them. The lawyer alone is obdurate.

The lawyer and the judge and the juryman are sure that they do not
need the experimental psychologist. They do not wish to see that
in this field pre‰minently applied experimental psychology has
made strong strides, led by Binet, Stern, Lipmann, Jung,
Wertheimer, Gross, Sommer, [p. 11] Aschaffenburg, and other
scholars. They go on thinking that their legal instinct and their
common sense supplies them with all that is needed and somewhat
more; and if the time is ever to come when even the jurist is to
show some concession to the spirit of modern psychology, public
opinion will have to exert some pressure. Just in the line of the law
it therefore seems necessary not to rely simply on the technical
statements of scholarly treatises, but to carry the discussion in the
most popular form possible before the wider tribunal of the
general reader.

With this aim in mind -- while working at a treatise on "Applied
Psychology," which is to cover the whole ground with technical
detail -- I have written the following popular sketches, which
select only a few problems in which psychology and law come in
contact. They deal essentially with the mind of the witness on the
witness stand; only the last, on the prevention of crime, takes
another direction. I have not touched so far the psychology of the
attorney, of the judge, or of the jury -- problems which lend
themselves to very interesting experimental treatment. Even the
psychology [p. 12] of the witness is treated in no way exhaustively;
my only purpose is to turn the attention of serious men to an
absurdly neglected field which demands the full attention of the
social community.

 

ILLUSIONS

THERE had been an automobile accident. Before the court one of
the witnesses, who had sworn to tell "the whole truth, and nothing
but the truth," declared that the entire road was dry and dusty; the
other swore that it had rained and the road was muddy. The one
said that the automobile was running very slowly; the other, that he
had never seen an automobile rushing more rapidly. The first
swore that there were only two or three people on the village road;
the other, that a large number of men, women, and children were
passing by. Both witnesses were highly respectable gentlemen,
neither of whom had the slightest interest in changing the facts as
he remembered them. 

I find among my notes another case, where everything depended
upon the time which had passed between a whistle signal from the
street and the noise of an explosion. It was of the greatest
importance for the court to know whether the time was long
enough to walk a certain distance for [p. 16] which at least half a
minute was needed. Of two unbiassed witnesses, one swore that
the time was less than ten seconds; the other that it was more than
one minute. Again, there was a case where it was essential to find
out whether at a certain riot the number of guests in the hall was
larger than the forty who had been invited to attend. There were
witnesses who insisted that there could not have been more than
twenty persons present, and others who were sure that they saw
more than ne hundred. In a case of poisoning, some members of
the family testified that the beverage had a disagreeable, sour taste,
others, that it was tasteless, and others, that it was sweet. In some
Bowery wrangle, one witness was quite certain that a rowdy had
taken a beer-mug and kept it in his fist while he beat with it the
skull of his comrade; while others saw that the two were separated
by a long table, and that the assailant used the mug as a missile,
throwing it a distance of six or eight feet. In another trial, one
witness noticed at the sea-shore in moonlight a woman with a
child, while another witness was not less sure that it was a man
with a dog. And only recently passengers in a [p. 17] train which
passed a courtyard were sure, and swore, that they had taken in at a
glance the distinct picture of a man whipping a child; one swore
that he had a clean-shaven face, a hat, and was standing, while
another swore that he had a full beard, no hat, and was sitting on a
bench. The other day two most reliable expert shorthand writers
felt sure that they had heard the utterances which they wrote down,
and yet the records differed widely in important points.

There is no need of heaping up such illustrations from actual
cases, as everyone who remembers the last half-dozen murder
trials of his city knows with what regularity these differences in
reports of witnesses occur. We may abstract from all cases which
demand technical knowledge; we want to speak here only of direct
observations and of impressions which do not need any special
acquaintance with the matter. Wherever real professional
knowledge is needed, the door is, of course, open to every variety
of opinion, and one famous expert may conscientiously contradict
the other. No, we speak here only of those impressions for which
every layman is prepared and [p. 18] where there can be no
difference of opinion. We further abstract entirely from all cases of
intentional deception; the witness who lies offers no psychological
interest for the student of illusions. And we exclude all questions
of mental disease. Thus there remain the unintentional mistakes of
the sound mind, -- and the psychologist must ask at once, Are they
all of the same order? Is it inasmuch as the contradictory evidence
has to be enough to label them simply as illusions memory. To
make memory responsible is indeed the routine way. It is generally
taken for granted that we all perceive our surroundings uniformly.
In case there were only twenty men in the hall, no one could have
seen one hundred, In case the road was muddy, no one can have
seen in dusty. In case the man was shaved, no one can have seen
the beard. If there is still disagreement, it must have crept in
through the trickery of memory. The perception must be correct;
its later reproduction may be false. But do we really all perceive
the same thing, and does it have the same meaning to us in our
immediated absorption of the surrounding world? Is the court
sufficiently aware [p. 19] of the great differences between men's
perceptions, and does the court take sufficient trouble to examine
the capacities and habits with which the witness moves through the
world which he believes he observes? Of course some kind of a
"'common-sense" consideration has entered, consciously or
unconsciously, into hundreds of judicial decisions, inasmuch as the
contradictory evidence has to be sifted. The judges have on such
occasions more of less boldly philosophised or psychologised on
their own account; but to consult the psychological authorities was
out of the question. Legal theorists have even proudly boasted of
the fact that the judges always found their way without
psychological advice, and yet the records of such cases, for
instance, in railroad damages, quickly show that the psychological
inspirations of the beach are often directly the opposite of
demonstrable facts. To be sure, the judge may bolster up the case
with preceding decisions, but even if the old decision was
justified, is such an amateur psychologist prepared to decide
whether the mental situation is really the same in the new case?
Such judicial self-help was unavoidable as long as the [p. 20]
psychology of earlier times was hazy and vague but all that has
changed with the exact character of the new psychology.

The study of these powers no longer lies outside of the realm of
science. The progress of experimental psychology makes it an
absurd incongruity that the State should devote its fullest energy to
the clearing up of all the physical happenings, but should never ask
the psychological expert to determine the value of that factor
which becomes most influential-the mind of the witness. The
demand that the memory of the witness should be tested with the
methods of modern psychology has been raised sometimes, but it
seems necessary to add that the study of his perceptive judgment
will have to find its way into the court-room, too.

Last winter I made, quite by the way, a little experiment with the
students of my regular psychology course in Harvard. Several
hundred young men, mostly between twenty and twenty-three, took
part. It was a test of a very trivial sort. I asked them simply,
without any theoretical introduction, at the beginning of an
ordinary lecture, to write down careful answers to a number [p. 21]
of questions referring to that which they would see or hear. I urged
them to do it as conscientiously and carefully as possible, and the
hundreds of answers which I received showed clearly that every
one had done his best. I shall confine my report to the first hundred
papers taken up at random. At first I showed them a large sheet of
white cardboard on which fifty little black squares were pasted in
irregular order. I exposed it for five seconds, and asked them how
many black spots were on the sheet. The answers varied between
twenty-five and two hundred. The answer, over one hundred, was
more frequent than that of below fifty. Only three felt unable to
give a definite reply. Then I showed a cardboard which contained
only twenty such spots. This time the replies ran up to seventy and
down to ten. We had here highly trained, careful observers, whose
attention was concentrated on the material, and who had full time
for quiet scrutiny. Yet in both cases there were some who believed
that they saw seven or eight times more points than some others
saw; and yet we should be disinclined to believe in the sincerity of
two witnesses, of whom one felt sure [p. 21] that he saw two
hundred persons in a hall in which the other found only
twenty-five. 

My next question referred to the perception of time. I asked the
students to give the number of seconds which passed between two
loud clicks. I separated the two clicks at first by ten seconds, and
in a further experiment by three seconds. When the distance was
ten, the answers varied between half a second and sixty seconds, a
good number judging forty-five seconds as the right time. The one
who called it half a second was a Chinese, while all those whose
judgments ranged from one second to sixty seconds were average
Americans. When the objective time was three seconds, the
answers varied between half a second and fifteen seconds. I
emphasise that these large fluctuations showed themselves in spite
of the fact that the students knew beforehand that they were to
estimate the time interval. The variations would probably have
been still greater if the question had been put to them after hearing
the sound without previous information; and yet a district attorney
hopes for a reliable reply when he inquires of a witness, perhaps of
a cabman, how [p. 23] much time passed by between a cry and the
shooting in the cab.

In my third experiment I wanted to find out how rapidity is
estimated. I had on the platform a large clock with a white dial
over which one black pointer moved once around in five seconds.
The end of the black pointer, which had the form of an arrow,
moved over the edge of the dial with a velocity of ten centimeters
in one second; that is, in one second the arrow moved through a
space of about a finger's length. Now, I made this clock go for a
whole minute, and asked the observers to watch carefully the
rapidity of the arrow, and to describe, either in figures or by
comparisons with moving objects, the speed with which that arrow
moved along. Most men preferred comparisons with other objects.
The list begins as follows: man walking slowly;
accommodation-train; bicycle-rider; funeral cortŠge in a city
street; trotting dog; faster than trot of man; electric car; express
train; goldfish in water; fastest automobile speed; very slowly, like
a snail; lively spider; and so on. Would it seem possible that
university students, trained in observation, could watch a
movement [p. 24] constantly through a whole minute, and yet
disagree whether it moved as slowly as a snail or as rapidly as an
express-train. And yet it is evident that the form of the experiment
excluded every possible mistake of memory and excluded every
suggestive influence. The observation was made deliberately and
without haste. Those who judged in figures showed not less
variation. The list begins: one revolution in two seconds; one
revolution in forty-five seconds; three inches a second; twelve feet
a second; thirty seconds to the hundred yards; seven miles an hour;
fifteen miles an hour; forty miles an hour; and so on. In reality the
arrow would have moved in an hour about a third of a mile. Not a
few of the judgments, therefore, multiplied the speed by more than
one hundred.

In my next test I asked the class to describe the sound they would
hear and to say from what source it came. The sound which I
produced was the tone of a large tuning-fork, which I struck with a
little hammer below the desk, invisibly to the students. Among the
hundred students whose papers I examined for this record were
exactly [p. 25] two who recognised it as a tuning-fork tone. All the
other judgments took it for a bell, or an organ-pipe, or a muffled
gong, or a brazen instrument, or a horn, or a 'cello string, or a
violin, and so on. Or they compared it with as different noises as
the growl of a lion, a steam whistle, a fog-horn, a fly-wheel, a
human song, and what not. The description, on the other hand,
called it: soft, mellow, humming, deep, dull, solemn, resonant,
penetrating, full, rumbling, clear, low; but then again, rough,
sharp, whistling, and so on. Again I insist that every one knew
beforehand that he was to observe the tone, which I announced by
a signal. How much more would the judgments have differed if the
tone had come in unexpectedly? -- a tone which even now
appeared so soft to some and so rough to others -- like a bell to one
and like a whistle to his neighbour.

I turn to a few experiments in which I showed several sheets of
white cardboard, of which each contained a variety of dark and
light ink-spots in a somewhat fantastic arrangement. Each of these
cards was shown for two seconds, and it was suggested that these
rough ink-drawings represented [p. 26] something in the outer
world. Immediately after seeing one, the students were to write
down what the drawing represented. In some cases the subjects
remained sceptical and declared that those spots did not represent
anything, but were merely blots of ink. In the larger number the
suggestion was effective, and a definite object was recognised. The
list of answers for one picture begins: soldiers in a valley; grapes; a
palace; river-bank; Japanese landscape; foliage; rabbit; woodland
scene; town with towers; rising storm; shore of lake; garden; flags;
men in landscape; hair in curling-papers; china plate; war picture;
country square; lake in a jungle; trees with stone wall; clouds;
harvest scene; elephant; map; lake with castle in background;
trees; and so on. The list of votes for the next picture, which had
finer details, started with: spider; landscape; turtle; butterfly;
woman's head; bunch of war-flags; ballet-dancers; crowd of
people; cactus plant; skunk going down a log; centipede; boat on
pond; crow's nest beetle; flower; island; and so forth. There are
hardly any repetitions, with the exception that the vague term
"landscape" occurs often. Of course, [p. 27] we know, since the
days of Hamlet and Polonius, that a cloud can look like a camel
and like a whale. And yet such an abundance of variations was
hardly to be foreseen.

My next question did not refer to immediate perception, but to a
memory image so vividly at every one's disposal that I assumed a
right to substitute it directly for a perception. I asked my men to
compare the apparent size of the full moon to that of some object
held in the hand at arm's length. I explained the question carefully,
and said that they were to describe an object just large enough,
when seen at arm's length, to cover the whole full moon. My list of
answers begins as follows: quarter of a dollar; fair-sized
canteloupe; at the horizon, large dinner plate, overhead,
dessert-plate; my watch; six inches in diameter; silver dollar;
hundred times as large as my watch; man's head; fifty-cent piece;
nine inches in diameter; grape-fruit; carriage-wheel; butter-plate;
orange; ten feet; two inches; one-cent piece; school-room clock; a
pea; soup-plate; fountain-pen; lemon-pie; palm of the hand; three
feet in diameter: enough to show, again, the overwhelming [p. 28]
manifoldness of the impressions received. To the surprise of my
readers, perhaps, it may be added at once that the only man who
was right was the one who compared it to a pea. It is most
probable that the results would not have been different if I had
asked the question on a moonlight night with the full moon
overhead. The substitution of the memory image for the immediate
perception can hardly have impaired the correctness of the
judgments. If in any court the size of a distant object were to be
given by witnesses, and one man declared it appeared as large as a
pea at arm's distance, and the second as large as a lemon-pie and
the third ten feet in diameter, it would hardly be fair to form an
objective judgment till the psychologist had found out which
mental factors were entering into that estimate.

There were many more experiments in the list; but as I want to
avoid all technicality, I refer to only two more, which are
somewhat related. First, I showed to the men some pairs of
coloured paper squares, and they had ample time to write down
which of the two appeared to them darker. At first it was a red and
a blue; then a blue and a green; [p. 29] and finally a blue and a
grey. My interest was engaged entirely with the last pair. The grey
was objectively far lighter than the dark blue, and any one with an
unbiassed mind who looked at those two squares of paper could
have not the slightest doubt that the blue was darker. Yet about
one-fifth of the men wrote that the grey was darker.

Now, let us keep this in mind in looking over the last experiment,
which I want to report. I stood on the platform behind a low desk
and begged the men to watch and to describe everything which I
was going to do from one given signal to another. As soon as the
signal was given, I lifted with my right hand a little revolving
wheel with a colour-disk and made it run and change its color, and
all the time, while I kept the little instrument at the height of my
head, I turned my eyes eagerly toward it. While this was going on,
up to the closing signal, I took with my left hand, at first, a pencil
from my vest-pocket and wrote something at the desk; then I took
my watch out and laid it on the table; then I took a silver
cigarette-box from my pocket, opened it, took a cigarette out of it,
closed it with a loud click, and [p. 30] returned it to my pocket;
and then came the ending signal. The results showed that eighteen
of the hundred had not noticed anything of all that I was doing
with my left hand. Pencil and watch and cigarettes had simply not
existed for them. The mere fact that I myself seemed to give all my
attention to the colour-wheel had evidently inhibited in them the
impressions of the other side. Yet I had made my movements of
the left arm so ostentatiously, and I had beforehand so earnestly
insisted that they ought to watch every single movement, that I
hardly expected to make any one overlook the larger part of my
actions. It showed that the medium, famous for her slate tricks,
was right when she asserted that as soon as she succeeded in
turning the attention of her client to the slate in her hand, he would
not notice if an elephant should pass behind her through the room. 

But the chief interest belongs to the surprising fact that of those
eighteen men, fourteen were the same who, in the foregoing
experiment, judged the light grey to be darker than the dark blue.
That coincidence was, of course, not chance. In the case of the
darkness experiment the mere idea [p. 31] of greyness gave to their
suggestible minds the belief that the colourless grey must be
darker than any colour. They evidently did not judge at all from
the optical impression, but entirely from their conception of grey
as darkness. The coincidence, therefore, proved clearly how very
quickly a little experiment such as this with a piece of blue and
grey paper, which can be performed in a few seconds, can pick out
for us those minds which are probably unfit to report, whether an
action has been performed in their presence or not. Whatever they
expect to see they do see; and if the attention is turned in one
direction, they are blind and deaf and idiotic in the other.

Enough of my class-room experiments. Might they not indeed
work as a warning against the blind confidence in the observations
of the average normal man, and might they not reinforce the
demand for a more careful study of the individual differences
between those on the witness stand? Of course, such study would
be one-sided if the psychologist were only to emphasise the
varieties of men and the differences by which one man's judgment
and observation may be counted on to throw [p. 32] out an
opposite report from that of another man. No, the psychologist in
the court-room should certainly give not less attention to the
analysis of those illusions which are common to all men and of
which as yet common sense knows too little. The jurymen and the
judge do not discriminate, whether the witness tells that he saw in
late twilight a woman in a red gown or one in a blue gown. They
are not expected to know that such a faint light would still allow
the blue colour sensation to come in, while the red colour
sensation would have disappeared.

They are not obliged to know what directions of sound are mixed
up by all of us and what are discriminated they do not know,
perhaps, that we can never be in doubt whether we heard on the
country road a cry from the right or from the left, but we may be
utterly unable to say whether we heard it from in front or from
behind. They have no reason to know that the victim of a crime;
nay have been utterly unable to perceive that he was stabbed with
a pointed dagger; he may have felt it like a dull blow. We hear the
witnesses talking about the taste of poisoned liquids, and there [p.
33] is probably no one in the jury-box who knows enough of
physiological psychology to be aware that the same substance may
taste quite differently on different parts of the tongue. We may
hear quarrelling parties in a civil suit testify as to the size and
length and form of a field as it appeared to them, and yet there is
no one to remind the court that the same distance must appear
quite differently under a hundred different conditions. The judge
listens, perhaps, to a description of things which the witness has
secretly seen through the keyhole of the door; he does not
understand why all the judgments as to the size of objects and their
place are probably erroneous under such circumstances. The
witness may be sure of having felt something wet, and yet he may
have felt only some smooth, cold metal. In short, every chapter and
sub-chapter of sense psychology may help to clear up the chaos
and the confusion which prevail in the observation of witnesses. 

But, as we have insisted, it is never a question of pure sense
perception. Associations, judgments, suggestions, penetrate into
every one of our observations. We know from the drawings of [p.
34] children how they believe that they see all that they know
really exists; and so do we ourselves believe that we perceive at
least all that we expect. I remember some experiments in my
laboratory where I showed printed words with an instantaneous
illumination. Whenever I spoke a sentence before-hand, I was able
to influence the seeing of the word. The printed word was courage:
I said something about the university life, and the subject read the
word as college. The printed word was Philistines: I, apparently
without intention, had said something about colonial policy, and
my subject read Philippines. In this way, of course, the fraudulent
advertisement makes us overlook some essential element which
may change the meaning of the offer entirely. Experimental
psychology has at last cleared the ground, and to ignore this whole
science and to be satisfied with the primitive psychology of
common sense seems really out of order when crime and
punishment are in question and the analysis of the mind of the
witness might change the whole aspect of the case. 

It is enough if we have to suffer from these mental varieties in our
daily life; at least the [p. 35] court-room ought to come nearer to
the truth, and ought to show the way. The other organs of society
may then slowly follow. It may be that, ultimately, even the
newspapers may learn then from the legal practice, and may take
care that their witnesses be examined, too, as to their capacity of
observation. Those experiments described from my class-room
recommend at least mildness of judgment when we compare the
newspaper reports with each other. Since I saw that my own
students do not know whether a point moves with the slowness of
a snail or with the rapidity of an express-train; whether a time
interval is half a second or a whole minute; whether there are
twenty-five points or two hundred; whether a tone comes from a
whistle, a gong, or a violin; whether the moon is small as a pea or
large as a man, -- I am not surprised any more when I read the
reports of the papers.

I had occasion recently to make an address on peace in New York
before a large gathering, to which there was an unexpected and
somewhat spirited reply. The reporters sat immediately in front of
the platform. One man wrote that the [p. 36] audience was so
surprised by my speech that it received it in complete silence;
another wrote that I was constantly interrupted by loud applause,
and that at the end of my address the applause continued for
minutes. The one wrote that during my opponent's speech I was
constantly smiling; the other noticed that my face remained grave
and without a smile. The one said that I grew purple-red from
excitement; and the other found that I grew white like chalk. The
one told us that my critic, while speaking, walked up and down the
large stage; and the other, that he stood all the while at my side
and patted me in a fatherly way on the shoulder. And Mr. Dooley
finally heard that before I made my speech on peace I was
introduced as the Professor from the Harvard War School -- but it
may be that Mr. Dooley was not himself present.

THE MEMORY OF THE WITNESS

LAST summer I had to face a jury as witness in a trial. While I was
with my family at the seashore my city house had been burglarised
and I was called upon to give an account of my findings against the
culprit whom they had caught with a part of the booty. I reported
under oath that the burglars had entered through a cellar window,
and then described what rooms they had visited. To prove, in
answer to a direct question, that they had been there at night, I told
that I had found drops of candle wax on the second floor. To show
that they intended to return, I reported that they had left a large
mantel clock, packed in wrapping paper, on the dining-room table.
Finally, as to the amount of clothes which they had taken, I
asserted that the burglars did not get more than a specified list
which I had given the police.

Only a few days later I found that every one of these statements
was wrong. They had not entered through the window, but had
broken the [p. 40] lock of the cellar door; the clock was not packed
by them in wrapping paper, but in a tablecloth; the candle
droppings were not on the second floor, but in the attic; the list of
lost garments was to be increased by seven more pieces; and while
my story under oath spoke always of two burglars, I do not know
that there was more than one. How did all those mistakes occur? I
have no right to excuse myself on the plea of a bad memory.
During the last eighteen years I have delivered about three
thousand university lectures. For those three thousand coherent
addresses I had not once a single written or printed line or any
notes whatever on the platform; and yet there has never been a
moment when I have had to stop for a name or for the connection
of the thought. My memory serves me therefore rather generously.
I stood there, also, without prejudice against the defendant.
Inasmuch as he expects to spend the next twelve years at a place of
residence where he will have little chance to read my writings, I
may confess frankly that I liked the man. I was thus under the most
favourable conditions for speaking the whole truth and nothing but
the truth, and, as [p. 41] there is probably no need for the
assurance of my best intentions, I felt myself somewhat alarmed in
seeing how many illusions had come in. 

Of course, I had not made any careful examination of the house. I
had rushed in from the seashore as soon as the police notified me,
in the fear that valuable contents of the house might have been
destroyed or plundered. When I saw that they had treated me
mildly, inasmuch as they had started in the wine cellar and had
forgotten under its genial influence, on the whole, what they had
come for, I had taken only a superficial survey. That a clock was
lying on the table, packed ready to be taken away, had impressed
itself clearly on my memory; but that it was packed in a tablecloth
had made evidently too slight an impression on my consciousness.
My imagination gradually substituted the more usual method of
packing with wrapping paper, and I was ready to take an oath on it
until I went back later, at the end of the summer vacation. In the
same way I got a vivid image of the candle droppings on the floor,
but as, at the moment of the perception, no interest was attached to
the peculiar place where I saw them, [p. 42] I slowly substituted in
my memory the second door for the attic, knowing surely from
strewn papers and other disorder that they had ransacked both
places. As to the clothes, I had simply forgotten that I had put
several suits in a remote wardrobe; only later did I find it empty.
My other two blunders clearly arose under the influence of
suggestion. The police and every one about the house had always
taken as a matter of course that the entrance was made by a cellar
window, as it would have been much more difficult to use the
locked doors. I had thus never examined the other hypothesis, and
yet it was found later that they did succeed in removing the lock of
a door. And finally, my whole story under oath referred to two
burglars, without any doubt at the moment. The fact is, they had
caught the gentleman in question when he, a few days later,
plundered another house. He then shot a policeman, but was
arrested, and in his room they found a jacket with my name written
in it by the tailor. That alone gave a hint that my house also had
been entered; but from the first moment he insisted that there had
been two in this burglary and that the other [p. 43] man had the
remainder of the booty. The other has not been found, and he
probably still wears my badges; but I never heard any doubt as to
his existence, and thus, in mere imitation, I never doubted that
there was a companion, in spite of the fact that every part of the
performance might just as well have been carried out by one man
alone; and, after all, it is not impossible that he should lie as well
as shoot and steal.

In this way, in spite of my best intentions, in spite of good memory
and calm mood, a whole series of confusions, of illusions, of
forgetting, of wrong conclusions, and of yielding to suggestions
were mingled with what I had to report under oath, and my only
consolation is the fact that in a thousand courts at a thousand
places all over the world, witnesses every day affirm by oath in
exactly the same way much worse mixtures of truth and untruth,
combinations of memory and of illusion, of knowledge and of
suggestion, of experience and wrong conclusions. Not one of my
mistakes was of the slightest consequence. But is it probable that
this is always so? Is it not more natural to suppose that every day
errors creep [ p. 44] into the work of justice through wrong
evidence which has the outer marks of truth and trust-worthiness?
Of course, judge and jury and, later, the newspaper reader try their
best to weigh the evidence. Not every sworn statement is accepted
as absolute reality. Contradictions between witnesses are too
familiar. But the instinctive doubt refers primarily to veracity. The
public in the main suspects that the witness lies, while taking for
granted that if he is normal and conscious of responsibility he may
forget a thing, but it would not believe that he could remember the
wrong thing. The confidence in the reliability of memory is so
general that the suspicion of memory illusions evidently plays a
small r“le in the mind of the juryman, and even the
cross-examining lawyer is mostly dominated by the idea that a
false statement is the product of intentional falsehood.

All this is a popular illusion against which modern psychology
must seriously protest. Justice would less often miscarry if all who
are to weigh evidence were more conscious of the treachery of
human memory. Yes, it can be said that, while the court makes the
fullest use of all the modern scientific [p. 45] methods when, for
instance, a drop of dried blood is to be examined in a murder case,
the same court is completely satisfied with the most unscientific
and haphazard methods of common prejudice and ignorance when
a mental product, especially the memory report of a witness, is to
be examined. No juryman would be expected to follow his general
impressions in the question as to whether the blood on the
murderer's shirt is human or animal. But he is expected to make up
his mind as to whether the memory ideas of a witness are objective
reproductions of earlier experience or are mixed up with
associations and suggestions. The court proceeds as if the
physiological chemistry of blood examination had made wonderful
progress, while experimental psychology, with its efforts to
analyse the mental faculties, still stood where it stood two
thousand years ago.

The fact is that experimental psychology has not only in general
experienced a wonderful progress during the last decades, but has
also given in recent years an unusual amount of attention to just
those problems which are involved on the witness stand. It is
perhaps no exaggeration [p. 46] to say that a new special science
has even grown up' which deals exclusively with the reliability of
memory. It started in Germany and has had there for some years
even a magazine of its own. But many investigations in France and
the United States tended from the start in the same direction, and
the work spread rapidly over the psychological laboratories of the
world. Rich material has been gathered, and yet practical
jurisprudence is, on the whole, still unaware of it; and while the
alienist is always a welcome guest in the court room, the
psychologist is still a stranger there. The Court would rather listen
for whole days to the "science" of the handwriting experts than
allow a witness to be examined with regard to his memory and his
power of perception, his attention and his associations, his volition
and his suggestibility, with methods which are in accord with the
exact work of experimental psychology. It is so much easier
everywhere to be satisfied with sharp demarcation lines and to
listen only to a yes or no; the man is sane or insane, and if he is
sane, he speaks the truth or he lies. The psychologist would upset
this satisfaction completely.

[p. 47] The administration of an oath is partly responsible for the
wrong valuation of the evidence. Its seriousness and solemnity
suggest that the conditions for complete truth are given if the
witness is ready not to lie. We are too easily inclined to confuse
the idea of truth in a subjective and in an objective sense. A
German proverb says, "Children and fools speak the truth," and
with it goes the old "In vino veritas." Of course, no one can
suppose that children, fools, and tipsy men have a deeper insight
into true relations than the sober and grown-up remainder of
mankind. What is meant is only that all the motives are lacking
which, in our social turmoil, may lead others to the intentional
hiding of the truth. Children do not suppress the truth, because
they are na‹ve; the fools do not suppress it, because they are
reckless; and the mind under the influence of wine does not
suppress it, because the suppressing mechanism of inhibition is
temporarily paralysed by alcohol. The subjective truth may thus be
secured, and yet the idle talk of the drunkard and the child and the
fool may be objectively untrue from beginning to end. It is in this
way only that the oath by its religious [p. 48] background and by
its connection with threatened punishment can work for truth. It
can and will remove to a high degree the intention to hide the
truth, but it may be an open question to what degree it can increase
the objective truthfulness.

Of course, everyone knows that the oath helps in at least one more
direction in curbing misstatements. It not only suppresses the
intentional lie, but it focusses the attention on the details of the
statement. It excludes the careless, hasty, chance recollection, and
stirs the deliberate attention of the witness. He feels the duty of
putting his best will into the effort to reproduce the whole truth
and nothing but the truth. No psychologist will deny this effect. He
will ask only whether the intention alone is sufficient for success
and whether the memory is really improved in every respect by
increased attention. We are not always sure that our functions run
best when we concentrate our effort on them and turn the full light
of attention on the details. We may speak fluently, but the moment
we begin to give attention to the special movements of our lips and
of our tongue in speaking [p. 49] and make a special effort to
produce the movements correctly, we are badly hampered. Is it so
sure that our memory works faultlessly simply because we
earnestly want it to behave well? We may try hard to think of a
name and it will not appear in consciousness; and when we have
thought of something else for a long time, the desired name
suddenly slips into our mind. May it not be in a similar way that
the effort for correct recollection under oath may prove powerless
to a degree which public opinion underestimates? And no
subjective feeling of certainty can be an objective criterion for the
desired truth. 

A few years ago a painful scene occurred in Berlin, in the
University Seminary of Professor von Liszt, the famous
criminologist. The Professor had spoken about a book. One of the
older students suddenly shouts, "I wanted to throw light on the
matter from the standpoint of Christian morality!" Another student
throws in, "I cannot stand that!" The first starts up, exclaiming,
"You have insulted me!" The second clenches his fist and cries, "If
you say another word --" The first draws a revolver. The second [p.
50] rushes madly upon him. The Professor steps between them
and, as he grasps the man's arm, the revolver goes off. General
uproar. In that moment Professor Liszt secures order and asks a
part of the students to write an exact account of all that has
happened. The whole had been a comedy, carefully planned and
rehearsed by the three actors for the purpose of studying the
exactitude of observation and recollection. Those who did not
write the report at once were, part of them, asked to write it the
next day or a week later; and others had to depose their
observations under cross-examination. The whole objective
performance was cut up into fourteen little parts which referred
partly to actions, partly to words. As mistakes there were counted
the omissions, the wrong additions and the alterations. The
smallest number of mistakes gave twenty-six per cent. of [sic]
erroneous statements; the largest was eighty per cent. The reports
with reference to the second half of the performance, which was
more strongly emotional, gave an average of fifteen per cent. more
[sic] mistakes than those of the first half. Words were put into the
mouths or men who had been [p. 51] silent spectators during the
whole short episode; actions were attributed to the chief
participants of which not the slightest trace existed; and essential
parts of the tragi-comedy were completely eliminated from the
memory of a number of witnesses.

This dramatic psychological experiment of six years ago opened
up a long series of similar tests in a variety of places, with a steady
effort to improve the conditions. The most essential condition
remained, of course, always the complete na‹vet‚ of the witnesses,
as the slightest suspicion on their part would destroy the value of
the experiment. It seems desirable even that the writing of the
protocol should still be done in a state of belief. There was, for
instance, two years ago in G”ttingen a meeting of a scientific
association, made up of jurists, psychologists, and physicians, all,
therefore, men well trained in careful observation. Somewhere in
the same street there was that evening a public festivity of the
carnival. Suddenly, in the midst of the scholarly meeting, the doors
open, a clown in highly coloured costume rushes in in mad
excitement, and a negro with a [p. 52] revolver in hand follows
him. In the middle of the hall first the one, then the other, shouts
wild phrases; then the one falls to the ground, the other jumps on
him; then a shot, and suddenly both are out of the room. The
whole affair took less than twenty seconds. All were completely
taken by surprise, and no one, with the exception of the President,
had the slighest [sic] idea that every word and action had been
rehearsed beforehand, or that photographs had been taken of the
scene. It seemed most natural that the President should beg the
members to write down individually an exact report, inasmuch as
he felt sure that the matter would come before the courts. Of the
forty reports handed in, there was only one whose omissions were
calculated as amounting to less than twenty per cent. of the
characteristic acts; fourteen had twenty to forty per cent. [sic] of
the facts omitted; twelve omitted forty to fifty per cent., and
thirteen still more than fifty per cent. But besides the omissions
there were only six among the forty which did not contain
positively wrong statements; in twenty-four papers up to ten per
cent, of the statements were free inventions, [p. 53] and in ten
answers -- hat is, in one-fourth of the papers, -- more than ten per
cent. [sic] of the statements were absolutely false, in spite of the
fact that they all came from scientifically trained observers. Only
four persons, for instance, among forty noticed that the negro had
nothing on his head; the others gave him a derby, or a high hat, and
so on. In addition to this, a red suit, a brown one, a striped one, a
coffee-coloured jacket, shirt sleeves, and similar costumes were
invented for him. He wore in reality white trousers and a black
jacket with a large red necktie. The scientific commission which
reported the details of the inquiry came to the general statement
that the majority of the observers omitted or falsified about half of
the processes which occurred completely in their field of vision.
As was to be expected, the judgment as to the time duration of the
act varied between a few seconds and several minutes.

It is not necessary to tell more of these dramatic experiments,
which have recently become the fashion and almost a sport, and
which will still have to be continued with a great variety of
conditions [p. 54] if the psychological laws involved are really to
be cleared up. There are many points, for instance, in which the
results seem still contradictory. In some cases it was shown that
the mistakes made after a week were hardly more frequent more
than those made after a day. Other experiments seemed to indicate
that the number of mistakes steadily increases with the length of
time which has elapsed. Again, some experiments suggest that the
memory of the two sexes is not essentially different, while the
majority of the tests seems to speak for very considerable
difference. Experiments with school children, especially, seem to
show that the girls have a better memory than the boys as far as
omissions are concerned; they forget less. But they have a worse
memory than the boys as far as correctness is concerned; they
unintentionally falsify more.

We may consider here still another point which is more directly
connected with our purpose. A well-known psychologist showed
three pictures, rich in detail, but well adapted to the interest of
children, to a large number of boys and girls. They looked at each
picture for fifteen seconds [p. 55] and then wrote a full report of
everything they could remember. After that they were asked to
underline those parts of their reports of which they felt so
absolutely certain that they would be ready to take an oath before
court on the underlined words. The young people put forth their
best efforts, and yet the results showed that there were almost as
many mistakes in the underlined sentences as in the rest. This
experiment has been often repeated and the results make clear that
this happens in a smaller and yet still surprising degree in the case
of adults also. The grown-up students of my laboratory commit
this kind of perjury all the time.

Subtler experiments which were carried on in my laboratory for a
long time showed that this subjective feeling of certainty can not
only obtain in different degrees, but has, with different individuals,
quite different mental structure and meaning. We found that there
were, above all, two distinct classes. For one of those types
certainty in the recollection of an experience would rest very
largely upon the vividness of the image. For the other type it would
depend upon the [p. 56] congruity of an image with other
previously accepted images; that is, on the absence of conflicts,
when the experience judged about is imagined as part of a wide
setting of past experiences. But the most surprising result of those
studies was perhaps that the feeling of certainty stands in no
definite relation to the attention with which the objects are
observed. If we turn our attention with strongest effort to certain
parts of a complex impression, we may yet feel in our recollection
more certain about those parts of which we hardly took notice than
about those to which we devoted our attention. The correlations
between attention, recollection, and feeling of certainty become
the more complex the more we carefully study them. Not only the
self-made psychology of the average juryman, but also the scanty
psychological statements which judge and attorney find in the
large compendiums on Evidence [sic] fall to pieces if a careful
examination approaches the mental facts.

The sources of error begin, of course, before the recollection sets
in. The observation itself may be defective and illusory; wrong
associations [p. 57] may make it imperfect; judgments may
misinterpret the experience; and suggestive influences may falsify
the data of the senses. Everyone knows the almost unlimited
individual differences in the power of correct observation and
judgment. Everyone knows that there are persons who, under
favourable conditions, see what they are expected to see. The
prestidigitateurs, [sic] the fakirs, the spiritualists could not play
their tricks if they could not rely on associations and suggestions,
and it would not be so difficult to read proofs if we did not usually
see the letters which we expect. But we can abstract here from the
distortions which enter into the perception itself; we have
discussed them before. The mistakes of recollection alone are now
the object of our inquiry and we may throw light on them from still
another side.

Many of us remember minutes in which we passed through an
experience with a distinct and almost uncanny feeling of having
passed through it once before. The words which we hear, the
actions which we see, we remember exactly that we experienced
them a long time ago. The case is rare with men, but with women
extremely [p. 58] frequent, and there are few women who do not
know the state. An idea is there distinctly coupled with the feeling
of remembrance and recognition, and yet it is only an-associated
sensation, resulting from fatigue or excitement, and without the
slightest objective basis in the past. The psychologist feels no
difficulty in explaining it, but it ought to stand as a great warning
signal before the minds of those who believe that the feeling of
certainty in recollection secures objective truth. There is no new
principle involved, of course, when the ideas which stream into
consciousness spring from one's own imagination instead of being
produced by the outer impressions of our surroundings. Any
imaginative thought may slip into our consciousness and may carry
with it in the same way that curious feeling that it is merely the
repetition of something we have experienced before.

A striking illustration is well known to those who have ever taken
the trouble to approach the depressing literature of modern
mysticism. There we find an abundance of cases reported which
seem to prove that either prophetic fortune [p. 59] tellers or
inspired dreams have anticipated the real future of a man's life
with the subtlest details and with the most uncanny foresight. But
as soon as we examine these wonderful stories, we find that the
coincidences are surprising only in those cases in which the
dreams and the prophecies have been written down after the
realisation. Whenever the visions were given to the protocol
before-hand, the percentage of true realisations remains
completely within the narrow limits of chance coincidents and
natural probability. In other words, there cannot be any doubt that
the reports of such prophecies which are communicated after
having been realised are falsified. That does not reflect in the least
on the subjective veracity; our satisfied client of the clever fortune
teller would feel ready to take oath to his illusions of memory; but
illusions they remain. He also, in most cases, feels sure that he told
the dream to the whole family the next morning exactly as it
happened; only when it is possible to call the members of the
family to a scientific witness stand, does it become evident that the
essentials of the dream varied in all directions from the real later
occurrence. The [p. 60] real present occurrence completely
transforms the reminiscences of the past prophecy and every
happening is apperceived with the illusory overtone of having been
foreseen.

We must always keep in mind that a content of consciousness is in
itself independent of its relation to the past and has thus in itself no
mark which can indicate whether it was experienced once before
or not. The feeling of belonging to our past life may associate
itself thus just as well with a perfectly new idea of our imagination
as with a real reproduction of an earlier state of mind. As a matter
of course, the opposite can thus happen, too; that is, an earlier
experience may come to our memory stripped of every reference to
the past, standing before our mind like a completely new product
of imagination. To point again to an apparently mysterious
experience: the crystal gazer feels in his half hypnotic state a free
play of inspired imagination, and yet in reality he experiences only
a stirring up of the deeper layers of memory pictures. They rush to
his mind without any reference to their past origin, picturing a
timeless truth which is surprisingly correct only [p. 61] because it
is the result of a sharpened memory. Yes, we fill the blanks of our
perceptions constantly with bits of reproduced memory material
and take those reproductions for immediate impressions. In short,
we never know from the material itself whether we remember,
perceive, or imagine, and in the borderland regions there must
result plenty of confusion which cannot always remain without
dangerous consequences in the court-room.

Still another phenomenon is fairly familiar to everyone, and only
the courts have not yet discovered it. There are different types of
memory, which in a very crude and superficial classification might
be grouped as visual, acoustical, and motor types. There are
persons who can reproduce a landscape or a painting in full vivid
colours and with sharp outlines throughout the field, while they
would be unable to hear internally a melody or the sound of a
voice. There are others with whom every tune can easily resound
in recollection and who can hardly read a letter of a friend without
hearing his voice in every word, while they are utterly unable to
awake an optical [p. 62] image. There are others again whose
sensorial reproduction is poor in both respects; they feel intentions
of movement, as of speaking, of writing, of acting, whenever they
reconstruct past experience. In reality the number of types is much
larger. Scores of memory variations can be discriminated. Let your
friends describe how they have before their minds yesterday's
dinner table and the conversation around it, and there will no be
two whose memory shows the same scheme and method. Now we
should not ask a short-sighted man for the slight visual details of a
far distant scene, yet it cannot be safer to ask a man of the
acoustical memory type for strictly optical recollections. No one
on the witness stand is to-day examined to ascertain in what
directions his memory is probably trustworthy and reliable; he may
be asked what he has seen, what he has heard, what he as spoken,
how he has acted, and yet even a most superficial test might show
that the mechanism of his memory would be excellent for one of
these four groups of questions and utterly useless for the others,
however solemnly he might keep his oath.

[p. 63] The courts will have to learn, sooner or later, that the
individual differences of men can be tested to-day by the methods
of experimental psychology far beyond anything which common
sense and social experience suggest. Modern law welcomes, for
instance, for identification of criminals all the discoveries of
anatomists and physiologists as to the individual differences; even
the different play of lines in the thumb is carefully registered in
wax. But no one asks for the striking differences as to those mental
details which the psychological experiments on memory and
attention, on feeling and imagination, on perception and
discrimination, on judgment and suggestion, on emotion and
volition, have brought out in the last decade. Other sciences are
less slow to learn. It has been found, for instance, that the
psychological speech impulse has for every individual a special
character as to intonation and melody. At once the philologists
came and made the most brilliant use of this psychological
discovery. They have taken, for instance, whole epic texts and
examined those lines as to which it was doubtful whether they
belonged originally to the poem or were later interpolations. [p.
64] Wherever the speech intonation agreed with that of the whole
song, they acknowledged the authentic origin, and where it did not
agree they recognised an interpolation of the text. Yet the lawyers
might learn endlessly more from the psychologists about
individual differences than the philologians [sic] have done. They
must only understand that the working of the mental mechanism in
a personality depends on the constant co”peration of simple and
elementary functions which the modern laboratory experiment can
isolate and test. If those simplest elements are understood, their
complex combination becomes necessary; just as the whole of a
geometrical curve becomes necessary as soon as its analytical
formula is understood for the smallest part. 

But the psychological assistance ought not to be confined to the
discrimination of memory types and other individual differences.
The experimentalist cannot forget how abundant are the new facts
of memory variations which have come out of experiments on
attention and inhibition. We know and can test with the subtlest
means the waves of fluctuating attention through which [p. 65]
ideas become reinforced and weakened. We know, above all, the
inhibitory influences which result from excitements and emotions
which may completely change the products of an otherwise
faithful memory.

A concrete illustration may indicate the method of the
experimenters. The judge has to make up his mind as soon as there
is any doubt on which side the evidence on an issue of fact
preponderates. If it can be presupposed that both sides intend to
speak the truth he is ready to consider that the one side had,
perhaps, a more frequent opportunity to watch the facts in
question, the other side, perhaps, saw them more recently; the one
saw them, perhaps, under especially impressive circumstances, the
other, perhaps, with further knowledge of the whole situation, and
so on. Of course, his buckram-bound volumes of old decisions
guide him, but those decisions report again only that the one or the
other judge, relying on his common-sense, thought recency more
weighty than frequency, or frequency more important than
impressiveness, or perhaps the opposite. It is the same way in
which common-sense [p. 66] tells a man what kind of diet is most
nourishing. Yet what responsible physician would ignore the
painstaking experiments of the physiological laboratory,
determining exactly the quantitative results as to the nourishing
value of eggs or milk or meat or bread? The judges ignore the fact
that with the same accuracy their common-sense can be
transformed into careful measurements the results of which may
widely differ from haphazard opinion. The psychologist, of course,
has to reduce the complex facts to simple principles and elements.
An investigation, devoted to this problem of the relative
effectiveness of recency, frequency, and vividness was carried on
in my psychological laboratory. Here we used simple pairs of
coloured papers and printed figures, or colours and words, or
words and figures, or colours and forms, and so on. A series of ten
such pairs may be exposed successively in a lighted field, each
time one colour and one figure of two digits. But one pair, perhaps
the third, is repeated as the seventh, and thus impresses itself by its
frequency; another pair, perhaps the fifth, comes with impressive
vividness, [p. 67] from the fact that instead of two digits, suddenly
three are used. The last pair has, of course, the advantage in that it
sticks to the mind from its position at the end; it remains the most
recent, which is not inhibited by any following pair. After a pause
the colours are shown again and every one of the subjects has to
write down the figures together with which he believes himself to
have seen the particular colours. Is the vivid pair, or the frequently
repeated pair, or the recent pair better remembered? Of course, the
experiment was made under most different conditions, with
different pauses, different material, different length of the series,
different influences, different distribution, different subjects, but
after some years of work, facts showed themselves which can
stand as facts. The relative value of the various conditions for
exact recollection became really measurable. They may and must
be corrected by further experiments, but they are raised from the
first above the level of the chance opinions of the
lawyer-psychologist.

All this remains entirely within the limits of the normal healthy
individuality. Nothing of all that [p. 68] we have mentioned
belongs to the domain of the physician. Where the alienist has to
speak, that is, where pathological amnesia destroys the memory of
the witness, or where hallucinations of disease, or fixed ideas
deprive the witness's remembrance of their value, there the
psychologist is not needed. It is in normal mental life and its
border-land regions that the progress of psychological science
cannot be further ignored. No railroad or ship company would
appoint to a responsible post in its service men whose eyesight had
not been tested for colour blindness. There may be only one among
thirty or forty who cannot distinguish at a distance the red from the
green lantern. Yet if he slips into the service without being tested,
his slight defect, which does not disturb him in practical life and
which he may never have noticed if he was not just picking red
strawberries among green leaves, may be sufficient to bring about
the most disastrous wrecking of two trains or the most horrible
collision of steamers. In the life of justice trains are wrecked and
ships are colliding too often, simply because the law does not care
to examine the mental colour blindness [p. 69] of the witness's
memory. And yet we have not even touched one factor which,
more than anything else, devastates memory and plays havoc with
our best intended recollections: that is, the power of suggestion.

THE DETECTION OF CRIME

As old as the history of crime is the history of cruelties exercised,
in the service of justice, for the discovery of criminal facts. Man
has the power to hide his knowledge and his memories by silence
and by lies, and the infliction of physical and mental pain has
always seemed the quickest way to untie the tongue and to force
the confession of truth. Through thousands of years, in every land
on the globe, accomplices have been named, crimes have been
acknowledged, secrets have been given up, under threats and
tortures which overwhelmed the will to resist. The imagination of
the Orient invented more dastardly tortures than that of the
Occident; the mediaeval Inquisition brought the system to perhaps
fuller perfection than later centuries; and to-day the fortresses of
Russia are said to witness tortures which would be impossible in
non-Slavic lands. And, although the forms have changed, can there
be any doubt that even in the United States brutality [p. 74] is still
a favourite method of undermining the mental resistance of the
accused? There are no longer any thumb-screws, but the lower
orders of the police have still uncounted means to make the
prisoner's life uncomfortable and perhaps intolerable, and to break
down his energy. A rat put secretly into a woman's cell may
exhaust her nervous system and her inner strength till she is unable
to stick to her story. The dazzling light and the cold-water hose
and the secret blow seem still to serve, even if nine-tenths of the
newspaper stories of the "third degree" are exaggerated. Worst of
all are the brutal shocks given with fiendish cruelty to the terrified
imagination of the suspect.

Decent public opinion stands firmly against such barbarism; and
this opposition springs not only from sentimental horror and from
aesthetic disgust: stronger, perhaps, than either of these is the
instinctive conviction that the method is ineffective in bringing out
the real truth. At all times, innocent men have been accused by the
tortured ones, crimes which were never committed have been
confessed, infamous lies have been invented, [p. 75] to satisfy the
demands of the torturers. Under pain and fear a man may make
any admission which will relieve his suffering, and, still more
misleading, his mind may lose the power to discriminate between
illusion and real memory. Enlightened juries have begun to
understand how the ends of justice are frustrated by such methods.
Only recently an American jury, according to the newspapers,
acquitted a suspect who, after a previous denial, confessed with
full detail to having murdered a girl whose slain body had been
found. The detectives had taken the shabby young man to the
undertaking-rooms, led him to the side of the coffin, suddenly
whipped back the sheet, exposing the white bruised face, and
abruptly demanded, "When did you see her?" He sank on his knees
and put his hands over his face; but they dragged him to his feet
and ordered him to place his right hand on the forehead of the
body. Shuddering, he obeyed, and the next moment again
collapsed. The detectives pulled him again to his feet, and fired at
him question after question, forcing him to stroke the girl's hair
and cheeks; and, evidently without control of his [p. 76] mind, he
affirmed all that his torturers asked, and, in his half-demented
state, even added details to his untrue story.

The clean conscience of a modern nation rejects every such brutal
scheme in the search of truth, and yet is painfully aware that the
accredited means for unveiling the facts are too often insufficient.
The more complex the machinery of our social life, the easier it
seems to cover the traces of crime and to hide the outrage by lies
and deception. Under these circumstances, it is surprising and
seems unjustifiable that lawyers and laymen alike should not have
given any attention, so far, to the methods of measurement of
association which experimental psychology has developed in
recent years. Of course, the same holds true of many other
methods of the psychological laboratory -- methods in the study of
memory and attention, feeling and will, perception and judgment,
suggestion and emotion. In every one of these fields the
psychological experiment could be made helpful to the purposes of
court and law. But it is the study and measurement of associations
which have particular value [p. 77] in those realms where the
barbarisms of the third degree were formerly in use. The
chronoscope of the modern psychologist has become, and will
become more and more, for the student of crime what the
microscope is for the student of disease. It makes visible that
which remains otherwise invisible, and shows minute facts which
allow a clear diagnosis. The physician needs his magnifier to find
out whether there are tubercles in the sputum: the legal
psychologist may in the future use his mental microscope to make
sure whether there are lies in the mind of the suspect.

The study of the association of ideas has attracted the students of
the human mind since the day of Aristotle; but only in the last
century have we come to inquire systematically into the laws and
causes of these mental connections. Of course, every one knows
that our memory ideas link themselves with our impressions -- that
a face reminds us of a name, or a name of a face; that one word
calls another to mind; that even smell or taste may wake in us
manifold associations. But out of such commonplaces grew a
whole systematic science, and the school of associationists began
to explain [p. 78] our entire mental life as essentially the interplay
of such associations. There are the outer associations of time and
place, where one thing reminds us of another together with which
we experienced it. There are inner associations, where one thing
awakens in our minds something else which has similarity to it, or
to which it is related as a part to the whole or the whole to a part,
and so on. The word "dog" may call up in my mind, perhaps, the
memory-picture of a particular dog, or the name of that dog, or the
idea of a house in which I saw it; or it may bring up the
superordinated idea, "animal," or the subordinated, "terrier," or the
co”rdinated, "cat," or the part, "tail"; or perhaps it may suggest to
me the German translation for dog, or a painting with dogs in it:
there are no end of possibilities. But the psychologists were not
satisfied with grouping the various cases; their chief aim was to
determine the conditions under which they arise, the influence
which the frequency or the recency or the vividness or the
combination of special experiences has on the choice of the
resulting idea.

In the last few decades, then, has arisen the new [p. 79] science,
experimental psychology, which, like physics and chemistry, has
its own workshops, wherein mental facts are brought under
experimental test in the same way as in the natural sciences. With
the application of experimental methods, the study of association
took at once a new turn. In the laboratory we are not confined to
the chance material which daily life offers; we can prepare and
control the situation. For instance, I may use a list of one hundred
substantives, and read one after the other to my subject, and ask
him to give me the first word which enters his mind. I receive thus
one hundred associations which are independent of any intentional
selection, showing just the paths of least resistance in the mind of
my man. I may use them, for instance, to make statistics as to their
character: if the outer associations prevail, I have a type of mind
before me other than in the case of a preponderance of inner
associations; if the superordinations prevail, I have an intellect
other than if the subordinations were in the majority. Or I may
study the influences of preceding impressions. Perhaps I read to
my man a story or showed him some pictures [p. 80] before I gave
him the one hundred words for association; the effect of that
recent experience will show itself at once. In this way the
variations are endless.

But one aspect dominates in importance: I can measure the time of
this connection of ideas. Suppose that both my subject and I have
little electrical instruments between the lips, which, by the least
movement of speaking, make or break an electric current passing
through an electric clockwork whose index moves around a dial
ten times in every second. One revolution of the index thus means
the tenth part of a second, and, as the whole dial is divided into
one hundred parts, every division indicates the thousandth part of a
second. My index stands quietly till I move my lips to make, for
instance, the word "dog." In that moment the electric current
causes the pointer to revolve. My subject, as soon as he hears the
word, is to speak out as quickly as possible the first association
which comes to his mind. He perhaps shouts out "cat," and the
movement of his lips breaks the current, stops the pointer, and thus
allows me to read from the clockwork in [p. 81] thousandth parts
of a second the time which passed between my speaking the word
and his naming the association. Of course, this time includes not
only the time for the process of association, but also the time for
the hearing of the word, for the understanding, for the impulse of
speaking, and so on. But all these smaller periods I can easily
determine. I may find out how long it takes if my subject does not
associate anything, but simply repeats the word I give him. If the
mere repetition of the word "dog" takes him 325 thousandths of a
second, while the bringing up of the word "cat" took 975
thousandths, I conclude that the difference of 650 thousandths was
necessary for the process of associating "cat" and "dog."

In this way, during the last twenty years, there has developed an
exact and subtle study of mental associations, and through such
very careful observation of the time-differences between
associations a deep insight has been won into the whole mental
mechanism. The slightest changes of our psychical connections
can be discovered and traced by these slight variations of time,
which [p. 82] are, of course, entirely unnoticeable so long as no
exact measurements are introduced. The last few years have finally
brought the latest step: the theoretical studies have been made
useful to practical life. Like many other branches of experimental
psychology, the doctrine of association has become adjusted to the
practical problems of education, of medicine, of art, of commerce,
and of law. It is the last which chiefly concerns us here -- a kind of
investigation which began in Germany and has since been
developed here and abroad.

For instance, our purpose may be to find out whether a suspected
person has really participated in a certain crime. He declares that
he is innocent, that he was not present when the outrage occurred,
and that he is not even familiar with the locality. An innocent man
will not object to our proposing a series of one hundred
associations to demonstrate his innocence. A guilty man, of
course, will not object, either, as a declination would indicate a
fear of betraying himself; he cannot refuse, and yet affirm his
innocence. Moreover, he will feel sure that no questions can bring
out any facts which he wants to keep hidden [p. 83] in his soul; he
will be on the lookout. As long as nothing more is demanded than
that he speak the first word which comes to his mind, when
another word is spoken to him, there is indeed no legal and no
practical reason for declining, as long as innocence is professed.
Such an experiment will at once become interesting in three
different directions as soon as we mix into our list of one hundred
words a number, perhaps thirty, which stand in more or less close
connection to the crime in question -- words which refer to the
details of the locality, or to the persons present at the crime, or to
the probable motive, or to the professed alibi, and so on. The first
direction of our interest is toward the choice of the associations.
Of course, every one believes that he would be sure to admit only
harmless words to his lips; but the conditions of the experiment
quickly destroy that feeling of safety. As soon as a dangerous
association rushes to the consciousness, it tries to push its way out.
It may, indeed, need some skill to discover the psychical influence,
as the suspected person may have self-control enough not to give
away the dangerous idea directly; but the suppressed idea [p. 84]
remains in consciousness, and taints the next association, or
perhaps the next but one, without his knowledge.

He has, perhaps, slain a woman in her room. and yet protests that
he has never been in her house. By the side of her body was a cage
with a canary-bird. I therefore mix into my list of words also
"bird." His mind is full of the gruesome memory of his heinous
deed. The word "bird," therefore, at once awakens the association
"canary-bird" in his consciousness; yet he is immediately aware
that this would be suspicious, and he succeeds, before the
dangerous word comes to his lips, in substituting the harmless
word "sparrow." Yet my next word, or perhaps my second or third
next, is "colour," and his prompt association is "yellow": the
canary-bird is still in his mind, and shows its betraying influence.
The preparation of the list of words to be called thus needs
psychological judgment and insight if a man with quick
self-control is to be trapped. In most cases, however, there is
hardly any need of relying on the next and following words, as the
primary associations for the critical words unveil [p. 85]
themselves for important evidence directly enough.

Yet not only the first associations are interesting. There is interest
in another direction in the associations which result from a second
and a third repetition of the series. Perhaps after half an hour, I go
once more through the whole list. The subject gives once more his
hundred replies. An analysis of the results will show that most of
the words which he now gives are the same which he gave the first
time; pronouncing the words has merely accentuated his tendency
to associate them in the same connection as before. If it was
"house" -- "window" first, then it will probably be " house"--
"window" again. But a number of associations have been changed,
and a careful analysis will show that these are first of all the
suspicious ones. Those words which by their connection with the
crime stir up deep emotional complexes of ideas will throw ever
new associations into consciousness, while the indifferent ones
will link themselves in a superficial way without change. To a
certain degree, this variation of the dangerous associations is
reinforced by the intentional [p. 86] effort of the suspected. He
does not feel satisfied with his first words, and hopes that other
words may better hide his real thoughts, not knowing that just this
change is to betray him. 

But most important is the third direction of inquiry: more
characteristic than the choice and the constancy of the associations
is their involuntary retardation by emotional influence. A word
which stirs emotional memories will show an association-time
twice or three times as long as a commonplace idea. It may be said
at once that it is not ordinarily necessary, even for legal purposes,
that the described measurement be in thousandths of a second; the
differences of time which betray a bad conscience or a guilty
knowledge of certain facts are large enough to be easily measured
in hundredths or even in tenths of a second; though measurements
for the theoretical purposes of psychology require, indeed, a
division of the second into a thousand parts. In the following legal
division I shall, therefore, refer to differences in tenths of a second
only.

The absolute time of associations is, of course, quite different for
different persons; to link [p. 87] familiar ideas like "chair" --
"table" or "black" -- "white" may take for the slow type more than
a full second, while the alert mind may not need more than half a
second. Thus we begin by finding the average for each individual,
and all our interest goes into the deviations from this average. That
a certain association should take one and a half seconds would be
a very suspicious retardation for the quick mind which normally
associates in three quarters, while it would be quite normal for the
slow thinker. And here, again, it may be mentioned that the
retardation is not always confined to the dangerous association
alone, but often comes in a still more pregnant way in the
following or the next following association, which on the surface
looks entirely harmless. The emotional shock has perturbed the
working of the mechanism, and the path for all associations is
blocked. The analysis of these secondary time-retardations is the
factor which demands the greatest psychological skill. A few
illustrations from practical life may make the whole method
clearer.

An educated young man of eighteen lived in the house of an uncle.
The old gentleman went to consult [p. 88] a nerve specialist in
regard to some slight nervous trouble of the younger friend. On
that occasion he confided his recent suspicion that the young man
might be a thief. Money had repeatedly been taken from a drawer
and from a trunk; until lately he had had suspicions only of the
servants; he had notified the police, and detectives had watched
them. He was most anxious to find out whether his new suspicion
was true, as he wanted, in that case, to keep the matter out of
court, in the interest of the family. The physician, Dr. Jung, in
Zurich, arranged that the young man come for an examination of
his nerves. He then proposed to him a list of a hundred
associations as part of the medical inspection. The physician said
"head," the patient associated "nose"; then "green" -- "blue,"
"water" -- "air," "long" -- "short," "five" -- "six," "wool" -- "cloth,"
and so on, the average time of these commonplace connections
being 1.6 seconds. But there were thirty-seven dangerous words
scattered among the hundred -- words that had to do with the
things in the room from which the money was abstracted, or with
the theft and its [p. 89] punishment, or with some possible
motives. There appeared, for instance, the word "thief." The
association "burglar" seemed quite natural, but it took the boy
suddenly 4.6 seconds to reach it. In the same way "police" -- "
theft" took 9.6 seconds, "jail" - "penitentiary" 4.2 seconds. In other
cases the dangerous word itself came with normal automatic
quickness, but the emotional disturbance became evident in the
retardation of the next word. For instance, "key" -- "false key" took
only 1.6 seconds, but the following trivial association
"stupid"--"clever" grew to 3.0 seconds. "Crime" -- "theft" came
again promptly in 1.8, but the inner shock was so strong that the
commonplace word "cook " was entirely inhibited and did not
produce an association at all in 20 seconds. In the same way
"bread" -- "water" rushed forward in 1.6 seconds, but this
characteristic choice, the supposed diet of the jail, stopped the
associative mechanism again for the following trivial word. It
would lead too far to go further into the analysis of the case, but it
may be added that a repetition of the same series showed the
characteristic variations in the region [p. 90] of the suspicious
words. While "crime" had brought "theft" the first time, it was the
second time replaced by "murder"; "discover" brought the first
time "wrong," the second time "grasp." In the harmless words there
was hardly any change at all. But, finally, a subtle analysis of the
selection of words and of the retardations pointed to sufficient
details to make a clear diagnosis. The physician told the young
man that he had stolen; the boy protested vehemently. Then the
physician gave him the subtle points unveiled by the associations --
how he had bought a watch with the money and had given presents
to his sister; and the boy confessed everything, and was saved from
jail by the early discovery. The brutalities of the third degree
would hardly have yielded such a complete result, nor the
technicalities of legal evidence, either.

Of course, this case is that of a highly sensitive mind with the
strong feelings of a bad conscience. A professional tough criminal
would not show such intense emotions, and hence not such long
retardations, if he were as unsuspicious and unaware of the
purposes of the experiment as that [p. 91] boy was. But what
would be the situation of such a trained criminal who had no
conscience and who knew beforehand that the experiment was to
determine whether or not he lied or spoke the truth?

In that case, another group of facts is to be considered. We might
expect from such a subject very little lengthening of the simple
association-time by emotion, but instead of it a considerable
lengthening by conscious effort to avoid suspicious and dangerous
associations, provided that he were anxious to hide the damaging
truth. As soon as a critical word were offered, he would be on the
look-out not to betray the first word which came over the threshold
of consciousness, but to make sure first that it was harmless, and
to replace it if it were dangerous. Experiment shows that such
watching and conscious sanctioning takes time, and the replacing
of the unfit word by a fitting word brings still larger loss of time;
nobody is able to look out for the harmlessness of his associations
and yet to associate them with the average quickness with which
the commonplace ideas are brought forth. If the dangerous words
show [p. 92]association-times of unusual shortness, it is necessary
to suppose that the subject of the experiment makes no effort to
suppress the truth; the short time proves that he lets the ideas go as
they will, without his sifting, sanctioning, and retouching. Even the
best bluffer will thus be trapped in his effort to conceal anything,
by time-differences which he himself cannot notice.

As an illustration of a case of such a type, I may speak of
experiments that I carried on recently for several days in a Western
penitentiary with a self-confessed multi-murderer. He played the
star witness in a trial against a man whom his confession accused
as an accomplice. It made hardly a difference whether the view of
the prosecution or the view of the defence was taken: seen from
any side, the witness offered a psychological problem of unusual
interest. And its importance did not decrease when it was found
out, through the verdict of the jury, that the defendant was
innocent and had no connection with the crimes of the witness. No
side doubted at any time that this was one of the most persistent
murderers of modern time, and no side could deny that he was, [p.
93] during the trial, an imperturbable witness with the mildest
manners, with quiet serenity, and with the appearance of a man
who has found his peace in God.

The first problem for the psychologist was whether the confession
of the witness was a chain of conscious lies or whether he himself
really believed what he told the court. No outer evidence was fit to
settle this question of his mental attitude, and it seemed thus
interesting to study whether it might be possible to decide it by the
association method.

I had the good chance to see the murderer at once on the witness
stand. As my seat was at the small table of the attorneys for the
prosecution, I had him only a few feet from me for careful
observation. I cannot deny that my impression on that first
morning was very unfavourable. His profile, especially the jaw,
appeared to me most brutal and vulgar; I also saw at once the
deformation of the ear, the irregularity in the movements of the
eyes, and the abnormal lower lip. That this was the profile of a
murderer seemed to me not improbable, but that this man had
become a sincere [p. 94] religious convert seemed to me quite
incredible. Yet, I did not consult my antipathies; I had to rely on
my experiments, which I started the following day. This is, of
course, not the place to set down a scientific report of the nearly
one hundred groups of tests and experiments which, were
completed; they belong in scholarly archives. Most of them
referred to the memory, the attention, the feelings, the will, the
judgment, and the suggestibility. Our interest here belongs only to
the association experiments and to some related tests. Thus the
report here covers only a small section of the case, and ignores
entirely everything which does not refer to the subjective veracity.

I told the witness directly that I had come to examine his mind and
find out what was really at the bottom of his heart. He at once
declared himself perfectly ready to undergo any test. If he thought
that he, the experienced poker-player, could easily hide his inmost
mind and could deceive me with cant and lies, I turned the tables
on him quickly. I began with some simple psychological tricks
with which every student of psychology is [p. 95] familiar, but
which were naturally unknown and somewhat uncanny to the
witness. For instance, I covered one of his eyes and asked him to
fixate with the other eye a little cross on the table, and to watch at
the same time a cent piece which I moved at the side of the cross.
Suddenly I told him that he would not see the cent any more --
indeed, it had disappeared; and as he did not know that we all have
a blind spot at the entrance-place of the optical nerve in the retina,
he was much struck by my foreknowledge of such a defect in his
eye. Or, I showed him the drawing of a stair which he saw as such;
observing his eye movements, I told him that he now did not see
the stair any more, but an overhanging wall, and again he was
astonished at my knowing everything in his soul. In a similar way,
I used some tactual illusions, and soon he was entirely under the
spell of the belief that I had some special scientific powers.

Then I began with a real experiment. I told him that I should call at
first fifty words, and each time, when he heard a word, he was to
name to me as quickly as possible the first thing which [p. 96]
came to his mind on the hearing of the word. I asked him not to
choose the words intentionally, but to let them go without any
reflection; I added that I should learn all from the ideas which he
would bring up. My first word was "river," he associated "water";
then "ox," he said "yoke"; "mountain," he said "hill"; "tobacco," he
said "pipe." All the interest thus seemed to belong to the choice of
the words, and he saw that I wrote his answers down. But the fact
is that I did something else also; I measured in fractions of a
second the time between my calling the word and his giving a
reply. Between his hearing of the word "river" and his speaking the
word "water," eight-tenths of a second passed; between "ox" --
"yoke," six-tenths; between "tobacco" -- "pipe," eight-tenths. On
the whole, seven to eight-tenths of a second was the very short
standard time for those associations which represented familiar
ideas.

Now, there were mixed in among the fifty words many which had
direct relation to his criminal career and to his professed religious
conversion -- for instance, the words confession, revolver, [p. 97]
religion, heaven, jury, death, Bible, pardon, railroad, blood, jail,
prayer, and some names of his victims and of his alleged
accomplices. Let us not forget that he was fully under the belief
that I had a special power to discover from his spoken words the
real tendencies of his mind. If he had had anything to hide, he
would have been constantly on the lookout that no treacherous
word should slip in. If a word like "confession" or something
similar were called among harmless ones, he would never shout at
once the first word which came to his mind, but would have
watched that no dangerous secret, perhaps "confession" --
"humbug," came out and betrayed him. He would have quickly
suppressed the word before it was spoken -- and yet, however
quickly he might have done it, it would have taken at least one or
two seconds more; and he would have used the longer time the
more freely, as he had no reason to suspect that time played any
part in the experiment.

But the results show the very remarkable fact that the dangerous
words brought, on the whole, no retardation of the associative
process. [p. 98] After "tobacco"--"pipe" came with the same
promptness "confession"--"truth," again in eight-tenths of a second,
a time entirely insufficient for any inner deliberation or sanction or
choice or correction: it is a time which just allows the speaking of
the first idea which arises in the mind. "Heaven" -- "God" took,
again, less than a second, and so "religion" -- "truth,'' "blood" --
"knife," "governor" -- "executive," "witness" -- "stand," "minister"
-- "pulpit," "mine-owner" -- "mine"; only "pardon" -- "peace,"
"death" -- "end," and similar more abstract words took about one
and a half seconds, a time which is still too short for real inhibition
and second thought. Even the names of his accomplices and of his
victims awoke associations in less than nine-tenths of a second.
The fact that these associations were produced by the witness in
the minimum time, which made deliberation impossible, while he
was convinced that the words would unveil his real mind, is strong
evidence indeed that this man did not want consciously to hide
anything, and that he himself really believed his confession.

[p. 99] If these experiments had been made with him before his
confession, he would have stumbled over every third word, and
many of his associations would have taken three seconds or more.
He would have been unable, in spite of best efforts, to overcome
the fear of betraying himself, and this fear would have retarded the
associations in away which would have trapped him unmistakably.
But not only the short time, the choice of the associations also
indicated clearly that, in an almost incredible manner, a mild,
indifferent serenity had taken hold of his mind, and that his
criminal life was of no concern to him any more. I gave him, for
instance, the name of a city in which, according to his confession,
he had been last to poison a victim and to dynamite his house; but
in his mind the place did not connect itself any more with murder;
in less than a second his mind joined it with "ocean."

It is evident from the association-times that no real emotion
accompanied any of his memories of crime. He did not have and
did not simulate a bad conscience. The emotional retardation of
suspicious associations, characteristic of the average [p. 100]
criminal, was, as expected, entirely lacking in this wholesale
murderer. That does not mean that he lacks feeling; my
experiments showed the opposite. To be sure, his sensitiveness for
pain was, as with most criminals, much below the average. A deep
pin-prick did not produce any reaction, and his whole touch sense
was obtuse, while his eyes and ears were very sharp. But, in spite
of this lack of organic pain, -- he has never been ill, -- he is
sensitive to the immediate perception of suffering in others.
Simulation is excluded: I measured the involuntary reactions. He
really shivers at the thought of hurting others. I have no reason for
doubting that he had this mental sensitiveness always; and that is
no contradiction to the fact that he was spreading pain all around.
Nearly all his crimes were performed in an impersonal way; he did
not see the victims. He manufactured infernal machines, laid
dynamite in the mines and bombs under gates, and thought of the
suffering of the victims as little as the manufacturer of children's
toys may think of the happiness of the little ones. He assured me
that in those fifteen years of heinous deeds he never struck any one
[p. 101] personally with his fist; that would have gone against his
nerves. He exhibited tender feeling in all directions; he selected,
for instance, very delicate colour combinations as those which he
liked best among many which I showed him. His favourite colour
seemed to be dark blue; any showy or loud dressing is disagreeable
to him. He asserts, even, that he rarely drank any strong drinks: one
glass of beer made him sleepy.

Yet his emotional life is simply dead -- the small figures of his
association-times would otherwise be quite impossible. And it may
be added that even if his religious conversion is genuine, his
so-called religion lacks also every sound and deep feeling; it is
thoroughly utilitarian; he serves God because he will reward him
after death.

The association experiments thus completely fulfilled their
purpose: they gave a definite reply to a definite question which
could hardly be answered by other methods of evidence. The
association experiments proved that the murderer did not try to
hide anything. Of course, this was only the first problem to be
solved in the case. From this state of subjective truthfulness which
interests [p. 102] the psychologist to the proof of objective truth
which interests the court is still a very long way. It would have
been possible, for instance, that all this was pseudo-religious
auto-suggestion, or that it was a systematic illusion brought forth
by the suggestions of detectives and lawyers, or that the witness
was hypnotised, or that his mind was diseased. The experimental
inquiry had to study all those and other possibilities; they formed
the chief part of my experiments, but they do not belong here, as
they have no relation to the method of association-measurement,
which was the only concern of this discussion.

Of course, the theoretical importance of the method is independent
of the practical importance of the cases in which it is applied.
Multi-murderers are rare; but the simplest case of wrong-doing
may demonstrate the success of the method just as well. No
sharper contrast could be possible than that between the brutal
criminal with his dynamite bombs and the lovely little girl with her
chocolate bonbons whom I had seen a short time before. She was
anemic and neurasthenic, and could not concentrate her attention
on her work [p. 103] for her college examinations. She came to me
for psychological advice. I asked her many questions as to her
habits of life. Among other things, she assured me that she took
wholesome and plentiful meals and was not allowed to buy sweets.
Then I began some psychological experiments, and, among other
tests, I started, at first rather aimlessly, with trivial associations.
Her average association-time was slow, nearly 2 seconds. Very
soon the word "money" brought the answer "candy," and it came
with the quickness of 1.4 seconds. There was nothing remarkable
in this. But the next word, "apron," harmless in itself, was 6
seconds in finding its association, and, furthermore, the association
which resulted was "apron" -- " chocolate." Both the retardation
and the inappropriateness of this indicated that the foregoing pair
had left an emotional shock, and the choice of the word
"chocolate" showed that the disturbance resulted from the
intrusion of the word "candy." The word "apron" had evidently no
power at all compared with those associations which were
produced by the candy-emotion.

I took this as a clue, and after twenty indifferent [p. 104] words
which slowly restored her calmness of mind, I returned to the
problem of sweets. Of course, she was now warned, and was
evidently on the lookout. The result was that when I threw in the
word "candy" again, she needed 4.5 seconds, and the outcome was
the na‹ve association "never." This "never" was the first
association that was neither substantive nor adjective. All the
words before had evidently meant for her simply objects; but
"candy" seemed to appeal to her as a hint, a question, a reproach,
which she wanted to repudiate. She was clearly not aware that this
mental change from a descriptive to a replying attitude was very
suspicious; she must even have felt quite satisfied with her reply,
for the next associations were short and to the point. After a while
I began on the same line again. The unsuspicious word "box"
brought quickly the equally unsuspicious "white"; and yet I knew
at once that it was a candy-box, for the next word, "pound,"
brought the association "two" and the following, "book," after
several seconds the unfit association "sweet." She was again not
aware that she had betrayed the path of her imagination. [p. 105]
In the course of three hundred associations I varied the subject
repeatedly, and she remained to the end unconscious that she had
given me all the information needed. Her surprise seemed still
greater than her feeling of shame when I told her that she skipped
her luncheons daily and had hardly any regular meals, but
consumed every day several pounds of candy. With tears she made
finally a full "confession." She had kept her injudicious diet a
secret, as she had promised her parents not to spend any money for
chocolate. The right diagnosis led me to make the right
suggestions, and after a few weeks her health and strength were
restored.

This trivial case with its foolish offence shows how psychological
detective work may also be useful outside of the sphere of law. It
not seldom becomes the serious interest of the educator and the
physician to disentangle hidden thoughts, and the "third degree'' of
the school and of the consultation-room might easily be replaced
by association experiments. On such a basis the nerve specialist
would frequently be able to make the right and helpful diagnosis
without the aid of any [p. 106] "confession" and without
awakening in the patient the slightest suspicion that his physician
had discovered the real source of the trouble. Experiments have
convinced me that the method may bring to light facts of which
even the patient himself is ignorant. Ideas which are connected in
his deepest soul, but which he cannot bring up voluntarily by mere
effort of memory, are sometimes brought to expression by the
mechanical devices of this association method. It seems that as
soon as a number of associations have been produced under
pressure of the desire to associate as quickly as possible, the mind
enters into a state of decreased inhibition, in which suppressed and
forgotten ideas rush forward.

This fact must become the more important, the more we learn,
under the guidance of the Vienna School, that one of the most
troublesome nervous diseases -- namely, hysteria -- results
principally from suppressed affective ideas, and can be cured by
awaking anew the restrained thought. Hysteria is "strangulated
emotion," and disappears when the forgotten emotional ideas are
brought to, conscious expression. One hysteric woman always be
[p. 107] came mute after sunset; another could not take any food
but liquids; another was constantly tortured by the hallucination of
the tobacco odour. Every physician knows a hundred such hysteric
symptoms. No one of these patients knew the reason or origin of
her trouble. Slowly the physician discovered the suppressed ideas,
which had had no chance to express themselves and had worked
disaster in their inhibited form. The woman who could not speak
at night had sat once at sunset years before, at the bedside of her
sick father; she had vehemently suppressed every sound in order
not to disturb him. As soon as this first scene was brought back to
her mind, she regained her voice. The woman who could not take
solid food had been obliged, years before, to suppress her disgust
when eating at the same table with a man who suffered from an
ugly disease. As soon as this starting-point was consciously
associated again, she was ready to dine like others. The woman
who smelled tobacco had long before heard by chance, in a room
full of smoke, that the man she loved was in love with another, and
she had had to suppress her emotion on account of the presence [p.
108] of others. As soon as she connected the smell again in
consciousness with that first strangulated emotion, the
hallucination disappeared. Hysteric contractions and an‘sthesias,
pathological impulses and inhibitions, can all be removed if the
long-forgotten emotional ideas with which the disturbance started
can be brought to light. Just here the association method seems
sometimes helpful. The psychologist who seeks to discover the
secret connections of ideas may thus, by his association method,
not only protect the innocent and unmask the guilty, but bring
health and strength to the nervous wreck.

Yet our chief interest belongs to the legal aspect of this method.
Carried out with the skill which only long laboratory training can
give, it has become, indeed, a magnifying-glass for the most subtle
mental mechanism, and by it the secrets of the criminal mind may
be unveiled. All this has, of course, no legal standing to-day, and
there is probably no one who desires to increase the number of
"experts" in our criminal courts. But justice demands that truth and
lies be disentangled. The time will come when the methods [p.
109] of experimental psychology cannot longer be excluded from
the court of law. It is well known that the use of stenographers in
trials once met with vehement opposition, while now the
shorthand record of the court procedure seems a matter of course.
The help of the psychologist will become not less indispensable.
The vulgar ordeals of the "third degree'' in every form belong to
the Middle Ages, and much of the wrangling of attorneys about
technicalities in admitting the "evidence" appears to not a few
somewhat out of date, too: the methods of experimental
psychology are working in the spirit of the twentieth century. The
"third degree" may brutalise the mind and force either correct or
falsified secrets to light; the time-measurement of association is
swifter and cleaner, more scientific, more humane, and more
reliable in bringing out the truth which justice demands. Of course,
we are only at the beginning of its development; the new method is
still in many ways imperfect, and if clumsily applied it may be
misleading; moreover, there exists no hard and fast rule which fits
every case mechanically. But all this indicates only that, just as the
bodily facts [p. 110] have to be examined by the chemist or the
physiologist, the mental facts must be examined also, not by the
layman, but by the scientific psychologist, with the training of a
psychological laboratory.

THE TRACES OF EMOTIONS

If a girl blushes when a boy's name is mentioned in the family
sitting-room, we feel sure, even if she protests, that he is not quite
indifferent to her young heart. If she opens a letter and grows pale
while reading it, she may assure us that the event is unimportant;
we know better. If she talks with you and every word makes you
believe that her entire interest belongs to you and your remarks, it
is enough for you to see that her fingers are playing nervously with
her fan, and that her breathing has become deep and vehement and
her eyes restless since a certain guest has entered the room; you
know she is hardly listening to you and waits only for him to
approach her. And if he does not come, -- she may be masterful in
simulation and the artificial smile may never leave the lips, yet you
will hear her disappointment in the timbre of her voice, you may
see it even in the width of the pupil of her eye. Yes, the hidden
feeling betrays itself often [p. 114] against the will of the best
comedian in life. It may be easy to suppress intentionally the
conspicuous movements by which we usually accentuate the
emotions. It is not necessary to become wild with anger and to
collapse in sorrow, we may even inhibit laughter and tears, and a
New Englander will never behave like a Southern Italian. But the
lips and hands and arms and legs, which are under our control, are
never the only witnesses to the drama which goes on inside -- if
they keep silent, others will speak. The poets know it well.
Through the dramatic literature of all ages is repeated the motive
of the unintentional expression of emotions. The ghastly memory
of a gruesome past seems locked up in the hero's mind; and yet
when he is brought back to the place of his deed, it comes to light
in his paleness and trembling, in the empty glaring of his eyes and
the breaking of his voice. There is hardly a tragedy of Shakespeare
in which the involuntary signs of secret excitement do not play
their r“le. And the comedies of all time vary the same motive with
regard to the lighter sins of love and social entanglement. The
helpless stammering of the excited [p. 115] lover betrays
everything which his deliberate words are to deny.

But the signs which made Hamlet sure that his mother had
committed murder have not been overlooked by those who are on
the track of the criminal in our practical life. The suspected man
who pales before the victim while he pretends not to know him, or
who weeps at hearing the story of the crimes which he disavows, is
half condemned in the eyes of the prosecutor. When the conspiracy
against Dreyfus sought to manufacture evidence against him, they
made much of the fact that he trembled and was thus hardly able to
write when they dictated to him a letter in which phrases of the
discovered treasonable manuscript occurred. Much of that which
the police and the delinquents call the third degree consists of
these bodily signs of a guilty conscience; to make the accused
break down from his own inner emotion is the triumph of such
maladministration of law. 

It seems that even some of the superstitions of barbaric times
which claimed to discover the guilty by all kinds of miracles
sometimes contained a certain truth of this kind. They depended
on apparently [p. 116] mysterious signs which in reality sometimes
belonged to the bodily effects of emotion. Evidently primitive life
sharpens the observation of such symptoms. One-of the most
adventurous "gunmen" of the West told me that when he was
attacked by mobs he behaved as if he were constantly spitting; he
went through such motions because it always discourages the
crowd when they see that their adversary does not fear them, and
they would know that a man who is afraid cannot spit -- the
emotion of fear dries up the mouth and throat.

Of course, everyone knows how uncertain and unsafe such crude
police methods must be. There cannot be justice if we base our
judgment on the detective's claim that a man blushed or trembled
or was breathing heavily. It would hardly be better than those
superstitious decisions of early times. There are too many who
believe that they see what they expect to see, and very different
emotions may express themselves with very similar symptoms.
The door is open for every arbitrariness if such superficial
observations were to count seriously for acquittal or for
conviction. [p. 117] But that provokes the natural question: cannot
science help us out? Cannot science determine with exacitude [sic]
and safety that which is vague in the mere chance judgment of
police officers? More than that: cannot science make visible that
which is too faint and weak to be noticed by the ordinary observer?
The bystander watches the expressions of the strong overwhelming
emotions--but can science, can experimental psychology, not bring
to light the traces of the whole interplay of feelings, the light and
passing ones as well as the strong, and the most hidden suggestions
of consciousness as well as heavy emotional storms?

The question is indeed pressing, as the idea of the psychological
expert in court cannot be withdrawn from public discussion. The
mental life, -- perception and memory, attention and thought,
feeling and will -- plays too important a r“le in court procedure to
reject the advice of those who devote their work to the study of
these functions. And especially the progress of modern psychology
has been too rapid in recent years to ignore it still with that
condescension which was in order [p. 118] at the time when
psychologists indulged in speculation and psychological
laboratories were unknown. To-day the psychologist operates with
the methods of exact science, and the method which is here
demanded seems entirely in harmony with his endeavours. The
problem is whether he can record objectively the passing
symptoms and whether he can get hold of expressions too faint to
be perceptible to our senses. But just that the laboratory
psychologist is aiming at constantly and successfully. Whether he
measures the time of mental acts or analyses the complex ideas,
whether he studies the senses or the volitions, he is always
engaged in connecting the vague inner impression with an outer
measurable fact which can be recorded, and in throwing full light
on that which escapes notice in ordinary life.

In the region of feelings and emotions the experimental methods
of psychology have been certainly not less successful than in other
fields of inner life. To confine ourselves to that special problem
which interested us from the point of view of law: the psychologist
can indeed register [p. 119] the symptoms of inner excitement and,
more than that, can show the effects of feelings and emotions of
which the mere practical observation does not give us any trace.
Yet even the subtlest detective work of the psychological
instruments refers only to the same bodily functions which make
us visibly blush in shame, pale and tremble in fear, shiver in
horror, weep in grief, perspire in anxiety, dance in joy, grow hot
and clench the fist in anger. Everywhere the blood vessels contract
or dilate, the heart beat changes, the glands increase or decrease
their activity, the muscles work irregularly: but the instruments
allow us to become aware of almost microscopic changes. We
may, perhaps, point to a variety of lines along which such inquiry
may move.

To begin with a very simple group of processes, we may start with
our ordinary movements is of the arm: does feeling influence
them? I can give my reply from a little diary of mine. I kept it
years ago. It was not the regulation diary -- there was no
sentimentality in it, but mostly figures. Its purpose was to record
the results of about twenty experiments which took about half an
hour's time. [p. 120] I had the material for these little experiments
always in my pocket and repeated them three or four times a day
throughout several months. I fell to experimenting whenever daily
life brought me into a characteristic mental state, such as emotion
or interest or fatigue or anything important to the psychologist.
One of these twenty experiments was the following: I attached to
the bottom of my waistcoat a small instrument which allowed me
to slide along an edge between thumb and fore-finger of the right
hand, both outwards and inwards. Now I had trained myself to
measure off in this way from memory distances of four and eight
inches. Under normal conditions my hand passed through these
distances with exactitude [sic] while the eyes were closed; the
apparatus registered carefully whether I made the distance too long
or too short. The results of many hundreds of these measurements
went into my diary together with a description of the mood in
which I was.

When I came to figure up the results after half a year's records I
found a definite relation between my feelings and my arm
movements. My diary indicated essentially three fundamental pairs
of [p. 121] feeling in the course of time. There was pleasure and
displeasure, there was excitement and depression, and there was
gravity and hilarity. The figures showed that in the state of
excitement both the outward and inward movements became too
long, and in the state of depression both became too short; in the
state of pleasure the outward movements became too long, the
inward movements too short; in the state of displeasure the
opposite -- the outward movements too short and the inward
movements too long. In the case of gravity or hilarity no constant
change in the length of the movement resulted, but the rhythm and
rapidity of the action was influenced by them.

Here were, for the first time, three distinct sets of feelings
separated and recognised through three distinct ways of bodily
behaviour. After the publication of my figures, others came from
other starting points to such division of our feelings into three
groups, while some believe that there are only two sets. Still others
hold, and I should not disagree, that pleasure and displeasure alone
are the fundamental feelings; that a colour or a sound is agreeable
seems primary, that it is exciting [p. 122] or soothing is secondary.
On the other hand the number of those secondary feelings seems to
me to-day still larger than it did at that time; I am inclined to
accept man more simple feelings and find for everyone
characteristic expressions of movement. All this becomes
important as soon as the psychologist begins to explain the
feelings and asks how far the sensations themselves enter as parts
into the feelings.

But what concerns us here is the fact that the pleasurable and the
unpleasurable mood betray themselves in opposite movement --
impulses of which we are unaware. I had meant in those hundreds
of cases to make exactly the same outward and inward movements
and yet the experiments disclosed the illusion. Of course, we all
know how in joy the outward movements are r