Ilitt ' \ V.\Vs>; l> 1 >' HUGO: MU-NSTE&BEEG (Horn^U Slam ^r^nl Slibrara Cornell University Library KF9660.M941912 On the witness stand; essays on psycholog 3 1924 020 165 928 WW] \^ Cornell University f Library The original of tliis book is in tine Cornell University Library. There are no known copyright restrictions in the United States on the use of the text. http://www.archive.org/details/cu31924020165928 ON THE WITNESS S'l^xVD ON THE WITNESS STAND ESSAYS ON PSYCHOLOGY AND CRIME BY HUGO MUNSTERBERG PKOFEBSOB OP PSYCHOLOGY HAEVAED TJNIVBESITY Garden City New York DOUBLEDAY, PAGE & COMPANY MCMXn Copyright, 1908, 6y The MeOiitre Compamy /b '^^ 1 Copyright, 1907, 1908, by The 8. S. McClure Company Copyright, 1908, by The International Magazine Company Copyright, 1908, by The Bobbs-HerriU Company TO MY COLLABORATORS IN THE HARVARD PSYCHOLOGICAL LABORATORY EDWIN BISSEL HOLT AND ROBERT MEARNS YERKES CONTENTS PAOE Introduction S Illusions 13 The Memory of the Witness 37 The Detection of Crime 71 The Traces of Emotions 111 Untrue Confessions 135 Suggestions in Court 173 Hypnotism and Crime 201 The Prevention of Crime ^X^^ INTRODUCTION, 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 lab- oratory 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 Psycho- logical 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 re- main unnoticed because it was such a rapid one, surprising in its extent even to those who started [3] INTRODUCTION it. When, as a young student, I went to the Uni- versity of Leipzig in the eighties of the last cen- tury, 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 grow- ing, and every year has seen the foundation of new institutes by the pupils of Wundt, and later by their pupils. The first German laboratory out- side 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. To-day there exists hardly a university which has not opened a workshop for this youngest of the natural sci- ences. 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 [4J INTRODUCTION experiments of its own; it rather took its prob- lems 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 impor- tance. 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 re- acted upon. But this again was an experimental result which evidently concerned, first of aU, the student of mental life. [5] IXTRODUCTIOX Tn this way all kinds of scientists who cared little for psychology had gathered the most vari- ous psychological results with experimental meth- ods, and the psychologists saw that they could not afford to ignore such results of natural sci- ence. It would not do to go on claiming, for in- stance, 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 per- formed. 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 psychol- ogist. 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 took [6] INTRODUCTION 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 di- rected 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 labora- tory 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 de- tachment 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, experi- ences and professions, it seems astonishing that no path led from the seclusion of the psycho- logical workshop to the market-place of the world. Of course this separation was no disadvantage [7] INTRODUCTION 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 soUd will be its foundations. But now experi- mental 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 Ufe, 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 ceUs and tables of reaction-times. No warning against such " yeUow 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 [8] INTRODUCTION which were not in view during the experiments. What is needed is to adjust research to the prac- tical problems themselves and thus, for instance, when education is in question, to start psycholog- ical experiments directly from educational prob- lems. Applied Psychology will then become an in- dependent experimental science which stands re- lated 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, med- icine, 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 [9] INTRODUCTION study of colour and form, of rhjthm and har- mony, of suggestion and assthetic emotion. And even the business world begins to understand that the eflFectiveness 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 miU-hands can reach the best results, and how advertisements ought to be shaped, and what belongs to ideal salesmanship. And experience shows that the pol- itician 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 law- yer alone is obdurate. The lawyer and the judge and the juryman are sure that they do not need the experimental psy- chologist. They do not wish to see that in this field preeminently applied experimental psychol- ogy has made strong strides, led by Binet, Stem, Lipmann, Jimg, Wertheimer, Gross, Sommer, [10] INTRODUCTION AschafFenburg, and other scholars. They go on thinking that their legal instinct and their com- mon 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 conces- sion 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 psy- [11] INTRODUCTION chology of the witness is treated in no way ex- haustively; 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. 1 12] ILLUSIONS ILLUSIONS Theee 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 witnfesses 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 every- thing 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 im- portance for the court to know whether the time was long enough to walk a certain distance for [15] ON THE WITNESS STAND 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 one hundred. In a case of poisoning, some mem- bers of the family testified that the beverage had a disagreeable, sour taste, others, that it was taste- less, and othei«, 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 [16] ILLUSIONS train which passed a courtyard were sure, and swore, that they had taken in at a glance the dis- tinct 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 utter- ances which they wrote down, and yet the records differed widely in important points. There is no need of heaping up such illustra- tions from actual cases, as everyone who remem- bers 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 Impres- sions for which every layman is prepared and [17] ON THE WITNESS STAND where there can be no difference of opinion. We further abstract entirely from all cases of inten- ' tional deception ; the witness who lies oflfers 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 enough to label them simply as illusions of memory. To make memory responsible is indeed the rou- tine 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 it 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 reproduc- tion may be false. But do we really all perceive the same thing, and does it have the same mean- ing to us in our immediated absorption of the sur- rounding world.? Is the court sufficiently aware of [18] ILLUSIONS the great differences between men's perceptions, and does the court take sufficient trouble to ex- amine the capacities and habits with which the wit- ness 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 oi 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 psycho- logical advice, and yet the records of such cases, for instance, in railroad damages, quickly show that the psychological inspirations of the bench 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 psy- chologist 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 [19] ON THE WITNESS STAND 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 out- side of the realm of science. The progress of ex- perimental psychology makes it an absurd in- congruity that the State should devote its fullest energy to the clearing up of all the physical hap- penings, 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 modem 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 psy- chology 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 lec- ture, to write down careful answers to a number [20] ILLUSIONS of questions referring to that which they would see or hear. I urged them to do it as conscien- tiously 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 re- port to the first hundred papers taken up at random. At first I showed them a large sheet of white cardboard on which fifty httle 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 re- ply. 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 [21 J ON THE WITNESS STAND 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 in- quires of a witness, perhaps of a cabman, how [22] ILLUSIONS much time passed by between a cry and the shoot- ing 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 cortege in a city street; trotting dog; faster than trot of man; electric car; ex- press train; goldfish in water; fastest automobile speed ; very slowly, like a snail ; lively spider ; and so on. Would it seem possible that university stu- dents, trained in observation, could watch a move- [23] ON THE WITNESS STAND ment 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 evi- dent 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 twa? seconds ; one revolution in forty-five seconds ; three inches a second; twelve feet a second; thirty sec- onds 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 [24 ] ILLUSIONS 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 instru- ment, 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 de- scription, on the other hand, called it: soft, mel- • low, humming, deep, dull, solemn, resonant, pene- trating, 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 sug- gested that these rough ink-drawings represented [25] ON THE WITNESS STAND something in the outer world. Immediately after seeing one, the students were to write down what the drawing represented. In some cases the sub- jects 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; Jap- anese landscape ; foliage ; rabbit ; woodland scene ; town with towers ; rising storm ; shore of lake ; garden; flags; men in landscape; hair in curhng- 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, [26] ILLUSIONS 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 sub- stitute it directly for a perception. I asked my men to compare the apparent size of the fuU 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 fuU moon. My list of answers begins as fol- lows: quarter of a dollar; fair-sized canteloupe; at the horizon, large dinner plate, overhead, des- sert-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; or- ange ; 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 diam- eter: enough to show, again, the overwhelming [27] ON THE WITNESS STAND 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 fuU moon overhead. The substitution of the memory image for the immediate perception can hardly have impaired the correctness of the judg- ments. If in any court the size of a distant object were to be given by witnesses, and one man de- clared it appeared as large as a pea at arm's dis- tance, 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 tiU the psy- chologist 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 aU 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 ; [28] ILLUSIONS and finally a blue and a grey. My interest was en- gaged 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 every- thing 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 in- strument 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 cig- arette-box from my pocket, opened it, took a cigarette out of it, closed it with a loud click, and [29] ON THE WITNESS STAND returned it to my pocket ; and then came the end- ing 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 inhib- ited in them the impressions of the other side. Yet I had made my movements of the left arm so osten- tatiously, and I had beforehand so earnestly in- sisted that they ought to watch every single move- ment, 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 suc- ceeded 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 [80 J ILLUSIONS 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 coinci- dencej 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 de- mand for a more careful study of the individual difi'erences between those on the witness stand? Of course, such study would be one-sided if the psy- chologist were only to emphasise the varieties of men and the differences by which one man's judg- ment and observation may be counted on to throw rsi 1 ON THE WITNESS STAND out an opposite report from that of another man. No, the psychologist in the court-room should cer- tainly 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 httle. The jurymen and the judge do not discriminate, whether the witness teUs that he saw in late twi- light 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 talk- ing about the taste of poisoned liquids, and there [32] ILLUSIONS 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 aU 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, judg- ments, suggestions, penetrate into every one of our observations. We know from the drawings of [33] ON THE WITNESS STAND 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 re- member some experiments in my laboratory where I showed printed words with an instantaneous il- lumination. 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 imiversity life, and the sub- ject 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 pritnitive 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 [34 J ILLUSIONS court-room ought to come nearer to the truth, and ought to show the way. The other organs of so- ciety may then slowly follow. It may be that, ulti- mately, 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 slow- ness 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 sur- prised 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 [S5] ON THE WITNESS STAND 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 u5 that my critic, while speaking, walked up and down the large stage; and the other, that he stood aU 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 in- troduced as the Professor from the Harvard War School — ^but it may be that Mr. Dooley was not himself present. \.S6-i THE MEMORY OF THE WITNESS 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 en- tered through the window, but had broken the [39] ON THE WITNESS STAND 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. Dur- ing 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 what- ever 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 defend- ant. 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 con- fess frankly that I liked the man. I was thus un- der the most favourable conditions for speaking the whole truth and nothing but the truth, and, as [40 1 THE MEMORY OF THE WITNESS 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 examina- tion of the house. I had rushed in from the sea- shore 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 table- cloth 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, [41] ON THE WITNESS STAND I slowly substituted in my memory the second floor 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 sug- gestion. 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 hy- pothesis, 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 ar- rested, 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 [42] THE MEMORY OF THE WITNESS 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 sug- gestions 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 [43] ON THE WITNESS STAND 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 wit- nesses 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 illu- sions evidently plays a small role in the mind of the juryman, and even the cross-examining lawyer is mostly dominated by the idea that a false state- ment is the product of intentional falsehood. All this is a popular illusion against which mod- em 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 modem sci- [44] THE MEMORY OF THE WITNESS entific 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 unsci- entific and haphazard methods of common preju- dice and ignorance when a mental product, espe- cially the memory report of a witness, is to be ex- amined. 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 prog- ress, while experimental psychology, with its ef- forts 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 atten- tion to just those problems which are involved on the witness stand. It is perhaps no exaggeration [45] ON THK WITNESS STAND 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 psycholog- ical 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 stiU 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 suggesti- bility, 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. [46] THE MEMORY OF THE WITNESS The administration of an oath is partly respon- sible for the wrong valuation of the evidence. Its seriousness and solemnity suggest that the condi- tions for complete truth are given if the witness is ready not to lie. We are too easily inclined to con- fuse the idea of truth in a subjective and in an objective sense. A German proverb says, " Chil- dren 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 naive; 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 re- [47] ON THE WITNESS STAND ligious 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 truthful- ness. Of course, everyone knows that the oath helps in at least one more direction in curbing misstate- ments. 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 in- tention 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 speak- [48] THE MEMORY OF THE WITNESS ing and make a special effort to produce the move- ments 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 sometljtig else for a long time, the de- sired 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 ob- jective criterion for the desired truth. A few years ago a painful scene occurred in Berlin, in tlie University Seminary of Professor von Liszt, the famous criminologist. The Pro- fessor had spoken about a book. One of the older students suddenly shouts, " I wanted to throw light on the matter from the standpoint of Chris- tian morality ! " Another student throws in, " I cannot stand that ! " The first starts up, ex- claiming, " You have insulted me ! " The second clenches his fist and cries, " If you say another word " The first draws a revolver. The sec- [49] ON THE WITNESS STAND ond 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 mo- ment 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 perform- ance was cut up into fourteen little parts which referred partly to actions, partly to words. As mistakes there were coimted the omissions, the wrong additions and the alterations. The smallest nvmiber of mistakes gave twenty-six per cent, of 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 mistakes than those of the first half. Words were put into the mouths of men who had been [60] THE MEMORY- OP THE WITNESS sileht spectators during the whole short episode; actions were attributed to the chief participants of which not the slightest trace existed ; and essen- tial parts of the tragi-comedy were completely eliminated from the memory of a number of wit- nesses. 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 im- prove the conditions. The most essential condition remained, of course, always the complete naivete of the witnesses, as the slightest suspicion on their part would destroy the value of the experi- ment. It seems desirable even that the writing of the protocol should still be done in a state of be- lief. There was, for instance, two years ago in Gottingen a meeting of a scientific association, made up of jurists, psychologists, and physicians, all, therefore, men well trained in careful observa- tion. Somewhere in the same street there was that evening a public festivity of the carnival. Sud- denly, 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 [51] ON THE WITNESS STAND revolver in hand follows him. In the middle of the haU 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 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, 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 inven- [52] THE MEMORY OP THE WITNESS tions, and in ten answers — that is, in one-fourth of the papers, — more than ten per cent, of the statements were absolutely false, in spite of the fact that they all came from scientifically trained observers. Only four persons, for in- stance, 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 cos- tumes 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 omit- ted 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 dura- tion of the act varied between a few seconds and several minutes. It is not necessary to tell more of these dra- matic experiments, which have recently become the fashion and almost a sport, and which will still have to be continued with a great variety of con- [63] ON THE WITNESS STAND ditions if the psychological laws involved are really to be cleared up. There are many points, for instance, in which the results seem still contra- dictory. In some cases it was shown that the mis- takes made after a week were hardly more frequent 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. Experi- ments with school children, especially, seem to show that the girls have a better memory than the boys as far as omissions are concerned; they for- get less. But they have a worse memory than the boys as far as correctness is concerned ; they unin- tentionally 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 [54 J THE MEMORY OF THE WITNESS 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 under- lined 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 ob- tain 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 cer- tainty 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 [55] ON THE WITNESS STAND congruity of an image with other previously ac- cepted 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 eflFort 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 psy- chological statements which judge and attorney find in the large compendiums on Evidence 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 [56] THE MEMORY OF THE WITNESS may make it imperfect; judgments may misinter- pret 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, the fakirs, the spirit- ualists 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 land almost uncanny feeling of having passed through it once before. The words which we hear, the actions which we see, we remember ex- actly that we experienced them a long time ago. The case is rare with men, but with women ex- [57] ON THE WITNESS STAND tremely 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 sensa- tion, 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 objec- tive truth. There is no new principle Involved, of course, when the ideas which stream into con- sciousness spring from one's own Imagination in- stead 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 modem mysticism. There we find an abundance of cases reported which seem to prove that either prophetic for- [58 J THE MEMORY OF THE WITNESS tune tellers or inspired dreams have anticipated the real future of a man's life with the subtlest de- tails 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. When- ever the visions were given to the protocol before- hand, the percentage of true reaKsations remains completely within the narrow limits of chance coin- cidents 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 illu- sions 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 fam- ily 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 [59] ON THE WITNESS STAND real present occurrence completely transforms the reminiscences of the past prophecy and every hap- pening 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 rela- tion 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 ex- periences only a stirring up of the deeper layers of memory pictures. They rush to his mind with- out any reference to their past origin, picturing a timeless truth which is surprisingly correct only [60] THE MEMORY OF THE WITNESS because it is the result of a sharpened memory. Yes, we fill the blanks of our perceptions con- stantly with bits of reproduced memory material and take those reproductions for immediate im- pressions. In short, we never know from the ma- terial itself whether we remember, perceive, or imagine, and in the borderland regions there must result plenty of confusion which cannot al- ways remain without dangerous consequences in the court-room. Still another phenomenon is fairly familiar to everyone, and only the courts have not yet dis- covered it. There are different types of memory, which in a very crude and superficial classification might be grouped as visual, acoustical, and mo- tor types. There are persons who can repro- duce a landscape or a painting in fuU vivid col- ours 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 recol- lection 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 [61] ON THE WITNESS STAND image. There are others again whose sensorial reproduction is poor in both respects; they feel intentions of movement, as of speaking, of writ- ing, of acting, whenever they reconstruct past ex- perience. In reality the number of types is much larger. Scores of memory variations can be dis- criminated. Let your friends describe how they have before their minds yesterday's dinner table and the conversation around it, and there will not 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 recol- lections. No one on the witness stand is to-day examined to ascertain in what directions his mem- ory 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. [62] THE MEMORY OF THE WITNESS The courts will have to learn, sooner or later, that the individual diiferences of men can be tested to-day by the methods of experimental psychology far beyond anything which common sense and social experience suggest. Modem 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 discrimina- tion, 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 char- acter 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 be- longed originally to the poem or were later in- [63] ON THE WITNESS STAND terpolatlons. Wherever the speech intonation agreed with that of the whole song, they acknowl- edged the authentic origin, and where it did not agree they recognised an interpolation of the text. Yet the lawyers might leam endlessly more from the psychologists about individual differ- ences than the philologians have done. They must only understand that the working of the mental mechanism In a personality depends on the con- stant cooperation of simple and elementary func- tions which the modem laboratory experiment can isolate and test. If those simplest elements arc understood, their complex combination becomes necessary; just as the whole of a geometrical curve becomes necessary as soon as its analytical formula is imderstood for the smallest part. But the psychological assistance ought not to be confined to the discrimination of memory types and other individual differences. The experimen- talist 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 [64] THE MEMORY OF THE WITNESS ideas become reinforced and weakened. We know, above all, the inhibitory influences which result from excitements and emotions which may com- pletely change the products of an otherwise faith- ful 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 preponder- ates. If it can be presupposed that both sides in- tend 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 impress- ive circumstances, the other, perhaps, with fur- ther knowledge of the whole situation, and so on. Of course, his buckram-bound volumes of old de- cisions guide him, but those decisions report again only that the one or the other judge, rely- ing on his common-sense, thought recency more weighty than frequency, or frequency more im- portant than impressiveness, or perhaps the op- posite. It is the same way in which common- [65] ON THE WITNESS STAND sense tells a man what kind of diet is most nour- ishing. Yet what responsible physician would ignore the painstaking experiments of the phys- iological 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 care- ful measurements the results of which may widely differ from haphazard opinion. The psycholo- gist, of course, has to reduce the complex facts to simple principles and elements. An investiga- tion, devoted to this problem of the relative ef- fectiveness of recency, frequency, and vividness was carried on in my psychological laboratory. Here we used simple pairs of coloiu-ed 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 success- ively 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 im- presses itself by its frequency ; another pair, per- haps the fifth, comes with impressive vividness, 166] THE MEMORY OF THE WITNESS from the fact that instead of two digits, sud- denly 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 re- cent pair better remembered? Of course, the ex- periment 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 cor- rected 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 [67] ON THE WITNESS STAND we have mentioned belongs to the domain of the physician. Where the alienist has to speak, that is, where pathological amnesia destroys the mem- ory of the witness, or where hallucinations of disease, or fixed ideas deprive the witness's remem- brance 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 dis- tinguish 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 dis- turb him in practical life and which he may never have noticed if he was not just picking red straw- berries 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 blind- [68] THE MEMORY OP THE WITNESS ness of the witness's memory. And yet we have not even touched one factor which, more than any- thing else, devastates memory and plays havoc with our best intended recollections: that is, the power of suggestion. [69] THE DETECTION OF CRIME 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 confes- sion 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 imag- ination of the Orient invented more dastardly tor- tures than that of the Occident ; the mediaeval In- quisition 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 bru- [78] ON THE WITNESS STAND tality 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 in- tolerable, 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 tor- tured ones, crimes which were never committed have been confessed, infamous lies have been in- [74 J THE DETECTION OF CRIME vented, to satisfy the demands of the torturers. Under pain and fear a man may make any ad- mission 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 pre- vious 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 cofBn, suddenly whipped back the sheet, ex- posing the white bruised face, and abruptly de- manded, " 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 ques- tion, forcing him to stroke the girl's hair and cheeks; and, evidently without control of his [75] ON THE WITNESS STAND 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 re- jects every such brutal scheme in the search of truth, and yet is painfully aware that the ac- credited means for unveiling the facts are too often insufficient. The more complex the ma- chinery 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 im justifiable that law- yers 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 psycho- logical laboratory — ^methods in the study of memory and attention, feeling and will, percep- tion and judgment, suggestion and emotion. In every one of these fields the psychological experi- ment could be made helpful to the purposes of court and law. But it is the study and measure- ment of associations which have particular value [76] THE DETECTION OF CRIME in those realms where the barbarisms of the third degree were formerly In use. The chronoscope of the modern psychologist has become, and will be- come more and more, for the student of crime what the microscope is for the student of disease. It makes visible that which remains otherwise in- visible, 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 at- tracted 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 them- selves 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 assoclationlsts began to explain [77] ON THE WITNESS STAND our entire mental life as essentially the interplay of such associations. There are the outer associa- tions 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, per- haps, 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 super- ordinated idea, " animal," or the subordinated, " terrier," or the coordinated, " 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 deter- mine the conditions under which they arise, the influence which the frequency or the recency or the vividness or the combination of special experi- ences has on the choice of the resulting idea. In the last few decades, then, has arisen the new [78] THE DETECTION OF CRIME science, experimental psychology, which, like physics and chemistry, has its own workshops, wherein mental facts are brought under experi- mental 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 oflFers; we can prepare and control the situation. For in- stance, I may use a list of one hundred substan- tives, 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 influ- ences of preceding impressions. Perhaps I read to my man a story or showed him some pictures [79] ON THE WITNESS STAND 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. Sup- pose that both my subject and I have little elec- trical instnunents between the lips, which, by the least movement of speaking, make or break an electric current passing through an electric clock- work 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 himdred 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 poin- ter 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 " cat," and the movement of his lips breaks the current, stops the pointer, and thus allows me to read from the clockwork in [80 J THE DETECTION OF CRIME thousandth parts of a second the time which passed between my speaking the word and his naming the association. Of course, this time in- cludes not only the time for the process of asso- ciation, 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 ob- servation of the time-differences between associa- tions 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 [81] ON THE WITNESS STAND are, of course, entirely unnotlceable so long as no exact measurements are introduced. The last few years have finally brought the latest step : the the- oretical studies have been made useful to practical life. Like many other branches of experimental psycholo^, the doctrine of association has be- come adjusted to the practical problems of educa- tion, 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 oc- curred, and that he is not even familiar with thp 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, wiU 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 [82] THE DETECTION OF CRIME 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 expeffment will at once become inte^resting in three different direc- tions as soon as we mix into our list of one hun- dred 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 [83] ON THE WITNESS STAND remains in consciousness, and taints the next asso- ciation, 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 hei 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 stiU in his mind, and shows its betraying influence. The prepara4)n 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 un- [84 J THE DETECTION OF CRIME veil themselves for important evidence directly enough. Yet not only the first associations are interest- ing. 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 rephes. 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 con- nection with the crime stir up deep emotional com- plexes of ideas will throw ever new associations into consciousness, while the indifferent ones wiU link themselves in a superficial way without change. To a certain degree, this variation of the dangerous associations is reinforced by the inten- [85] ON THE WITNESS STAND tional 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 know- ing 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 involun- tary retardation by emotional influence. A word which stirs emotional memories will show an asso- ciation-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 pur- poses, that the described measurement be In thou- sandths 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 meas- ured 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 differ- ences in tenths of a second only. The absolute time of associations Is, of course, quite different for different persons; to link [86] THE DETECTION OF CRIME 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 inter- est goes into the deviations from this average. That a certain association should take one and a half seconds would be a very suspicious retarda- tion 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 con- fined to the dangerous association alone, but often comes in a still more pregnant way in the follow- ing or the next following association, which on the surface looks entirely harmless. The emotional shock has perturbed the working of the mechan- ism, and the path for all associations is blocked. The analysis of these secondary time-retardations is the factor which demands the greatest psycho- logical 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 con- [87] ON THE WITNESS STAND suit 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 repeat- edly 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 physi- cian, 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 associa- tions 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 sec- onds. 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 [88] THE DETECTION OF CRIME its 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 3.6 seconds, " jail " — " penitentiary " 4.2 seconds. In other cases the dangerous word itself came with normal automatic quickness, but the emotional dis- turbance 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 sec- onds. " 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 charac- teristic 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 [89] ON THE WITNESS STAND 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 physi- cian 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 bv +>■-