Illusions Part 13

We may conveniently proceed in our detailed examination of illusions of memory, by distinguishing between three facts which appear to be involved in every complete and accurate process of recollection. When I distinctly recall an event, I am immediately sure of three things: (1) that something did really happen to me; (2) that it happened in the way I now think; and (3) that it happened when it appears to have happened.

I cannot be said to recall a past event unless I feel sure on each of these points. Thus, to be able to say that an event happened at a particular date, and yet unable to describe how it happened, means that I have a very incomplete recollection. The same is true when I can recall an event pretty distinctly, but fail to a.s.sign it its proper date. This being so, it follows that there are three possible openings, and only three, by which errors of memory may creep in. And, as a matter of fact, each of these openings will be found to let in one cla.s.s of mnemonic illusion. Thus we have (1) false recollections, to which there correspond no real events of personal history; (2) others which misrepresent the manner of happening of the events; and (3) others which falsify the date of the events remembered.

It is obvious, from a mere glance at this threefold cla.s.sification, that illusions of memory closely correspond to visual illusions. Thus, cla.s.s (1) may be likened to the optical illusions known as subjective sensations of light, or ocular spectra. Here we can prove that there is nothing actually seen in the field of vision, and that the semblance of a visible object arises from quite another source than that of ordinary external light-stimulation, and by what may be called an accident.

Similarly, in the case of the first cla.s.s of mnemonic illusions, we shall find that there is nothing actually recollected, but that the mnemonic spectra or phantoms of recollected objects can be accounted for in quite another way. Such illusions come nearest to hallucinations in the region of memory.

Again, cla.s.s (2) has its visual a.n.a.logue in those optical illusions which depend on effects of haziness and of the action of refracting media interposed between the eye and the object; in which cases, though there is some real thing corresponding to the perception, this is seen in a highly defective, distorted, and misleading form. In like manner, we can say that the images of memory often get obscured, distorted, and otherwise altered when they have receded into the dim distance, and are looked back upon through a long s.p.a.ce of intervening mental experience.

Finally, cla.s.s (3) has its visual counterpart in erroneous perceptions of distance, as when, for example, owing to the clearness of the mountain atmosphere and the absence of intervening objects, the side of the Jungfrau looks to the inexperienced tourist at Wengernalp hardly further than a stone's throw. It will be found that when our memory falsifies the date of an event, the error arises much in the same way as a visual miscalculation of distance.

This threefold division of illusions of memory is plainly a rather superficial one, and not based on distinctions of psychological nature or origin. In order to make our treatment of the subject scientific as well as popular, it will be necessary to introduce the distinction between the pa.s.sive and the active factor under each head. It will be found, I think, without forcing the a.n.a.logy too far, that here, as in the case of the illusions of perception and introspection, error is attributable now to misleading suggestion on the part of the mental content of the moment, now to a process of incorporating into this content a mental image not suggested by it, but existing independently.

If we are to proceed as we did in the case of the illusions of sense, and take up the lower stages of error first of all, we shall need to begin with the third cla.s.s of errors, those of localization in time, or of what may be called mnemonic perspective. It has been already observed that the definite localization of a mnemonic image is only an occasional accompaniment of what is loosely called recollection. Hence, error as to the position of an event in the past chain of events would seem to involve the least degree of violation of the confidence which we are wont to repose in memory. After this, we may proceed to the discussion of the second cla.s.s, which I may call distortions of the mnemonic picture. And, finally, we may deal with the most signal and palpable variety of error of memory, namely, the illusions which I have called mnemonic spectra.

_Illusions of Perspective: A. Definite Localization._

In order to understand these errors of mnemonic perspective, we shall have to inquire more closely than we have yet done into the circ.u.mstances which customarily determine our idea of the degree of propinquity or of remoteness of a past event. And first of all, we will take the case of a complete act of recollection when the mind is able to travel back along an uninterrupted series of experiences to a definitely apprehended point. Here there would seem, at first sight, to be no room for error, since this movement of retrospective imagination may be said to involve a direct measurement of the distance, just as a sweep of the eye over the ground between a spectator and an object affords a direct measurement of the intervening s.p.a.ce.

Modern science, however, tells us that this mode of measurement is by no means the simple and accurate process which it at first seems to be. In point of fact, there is something like a constant error in all such retrospective measurement. Vierordt has proved experimentally, by making a person try to reproduce the varying time-intervals between the strokes of the pendulum of a metronome, that when the interval is a very small one, we uniformly tend to exaggerate it in retrospection; when a large one, to regard it, on the contrary, as less than it actually was.[117]

A mere act of reflection will convince any one that when he tries to conceive a very small interval, say a quarter of a second, he is likely to make it too great. On the other hand, when we try to conceive a year, we do not fully grasp the whole extent of the duration. This is proved by the fact that merely by spending more time over the attempt, and so recalling a larger number of the details of the period, we very considerably enlarge our first estimate of the duration. And this leads to great discrepancies in the appreciation of the relative magnitudes of past sections of time. Thus, as Wundt observes, though in retrospect both a month and a year seem too short, the latter is relatively much more shortened than the former.[118]

The cause of this constant error in the mode of reproducing durations seems to be connected with the very nature of the reproductive act. It must be borne in mind that this act is itself, like the experience which it represents, a mental process, occupying time, and that consequently it may very possibly reflect its time-character on the resulting judgment. Thus, since it certainly takes more than a quarter of a second to pa.s.s in imagination from one impression to another, it may be that we tend to confound this duration with that which we try to represent.

Similarly, the fact that in the act of reproductive imagination we under-estimate a longer interval between two impressions, say those of the slow beats of a colliery engine, may be accounted for by the supposition that the imagination tends to pa.s.s from the one impression to the succeeding one too rapidly.[119]

The gross misappreciation of duration of long periods of time, while it may ill.u.s.trate the principle just touched on, clearly involves the effect of other and more powerful influences. A mere glance at what is in our mind when we recall such a period as a month or a year, shows that there is no clear concrete representation at all. Time, it has been often said, is known only so far as filled with concrete contents or conscious experiences, and a perfect imagination of any particular period of past time would involve a retracing of all the successive experiences which have gone to make up this section of our life. This, I need not say, never happens, both because, on the one hand, memory does not allow of a complete reproduction of any segment of our experience, and because, on the other hand, such an imaginative reproduction, even if possible, would clearly occupy as much time as the experience itself.[120]

When I call up an image of the year just closing, what really happens is a rapid movement of imagination over a series of prominent events, among which the succession of seasons probably occupies the foremost place, serving, as I have remarked, as a framework for my retrospective picture. Each of the events which I thus run over is really a long succession of shorter experiences, which, however, I do not separately represent to myself. My imaginative reproduction of such a period is thus essentially a greatly abbreviated and symbolic mode of representation. It by no means corresponds to the visual imagination of a large magnitude, say that of the length of sea horizon visible at any one moment, which is complete in an instant, and quite independent of a successive imagination of its parts or details. It is essentially a very fragmentary and defective numerical idea, in which, moreover, the real quant.i.tative value of the units is altogether lost sight of.

Now, it seems to follow from this that there is something illusory in all our recallings of long periods of the past. It is by no means strictly correct to say that memory ever reinstates the past. It is more true to say that we see the past in retrospect as greatly foreshortened.

Yet even this is hardly an accurate account of what takes place, since, when we look at an object foreshortened in perspective, we see enough to enable us imaginatively to reconstruct the actual size of the object, whereas in the case of time-perspective no such reconstruction is even indirectly possible.

It is to be added that this constant error in time-reproduction is greater in the case of remote periods than of near ones of the same length. Thus, the retrospective estimate of a duration far removed from the present, say the length of time pa.s.sed at a particular school, is much more superficial and fragmentary than that of a recent corresponding period. So that the time-vista of the past is seen to answer pretty closely to a visible perspective in which the amount of apparent error due to foreshortening increases with the distance.

In practice, however, this defect in the imagination of duration leads to no error. Although, as a concrete image answering to some definite succession of experiences a year is a gross misrepresentation, as a general concept implying a collection of a certain number of similar successions of experience it is sufficiently exact. That is to say, though we cannot imagine the _absolute_ duration of any such cycle of experience, we can, by the simple device of conceiving certain durations as multiples of others, perfectly well compare different periods of times, and so appreciate their _relative_ magnitudes.

Leaving, then, this constant error in time-appreciation, we will pa.s.s to the variable and more palpable errors in the retrospective measurement of time. Each person's experience will have told him that in estimating the distance of a past event by a mere retrospective sense of duration, he is liable to extraordinary fluctuations of judgment. Sometimes when the clock strikes we are surprised at the rapidity of the hour. At other times the timepiece seems rather to have lagged behind its usual pace.

And what is true of a short interval is still more true of longer intervals, as months and years. The understanding of these fluctuations will be promoted by our brief glance at the constant errors in retrospective time-appreciation.

And here it is necessary to distinguish between the sense of duration which we have during any period, and the retrospective sense which survives the period, for these do not necessarily agree. The former rests mainly on our prospective sense of time, whereas the latter must be altogether retrospective.[121]

Our estimate of time as it pa.s.ses is commonly said to depend on the amount of consciousness which we are giving to the fact of its transition. Thus, when the mind is unoccupied and suffering from _ennui_, we feel time to move sluggishly. On the other hand, interesting employment, by diverting the thoughts from time, makes it appear to move at a more rapid pace. This fact is shown in the common expressions which we employ, such as "to kill time," and the German _Langweile_.

Similarly, it is said that when we are eagerly antic.i.p.ating an event, as the arrival of a friend, the mere fact of dwelling on the interval makes it appear to swell out.[122]

This view is correct in the main, and is seen, indeed, to follow from the great psychological principle that what we attend to exists for us more, has more reality, and so naturally seems greater than what we do not attend to. At the same time, this principle must be supplemented by another consideration. Suppose that I am very desirous that time should not pa.s.s quickly. If, for example, I am enjoying myself or indulging in idleness, and know that I have to be off to keep a not very agreeable engagement in a quarter of an hour, time will seem to pa.s.s too rapidly; and this not because my thoughts are diverted from the fact of its transition, for, on the contrary, they are reverting to it more than they usually do, but because my wish to lengthen the interval leads me to represent the unwelcome moment as further off than it actually is, in other words, to construct an ideal representation of the period in contrast with which the real duration looks miserably short.

Our estimate of duration, when it is over, depends less on this circ.u.mstance of having attended to its transition than on other considerations. Wundt, indeed, seems to think that the feeling accompanying the actual flow of time has no effect on the surviving subjective appreciation; but this must surely be an error, since our mental image of any period is determined by the character of its contents. Wundt says that when once a tedious waiting is over, it looks short because we instantly forget the feeling of tedium. My self-observation, as well as the interrogation of others, has satisfied me, on the contrary, that this feeling distinctly colours the retrospective appreciation. Thus, when waiting at a railway station for a belated train, I am distinctly aware that each quarter of an hour looks long, not only as it pa.s.ses, but when it is over. In fact, I am disposed to express my feeling as one of disappointment that only so short an interval has pa.s.sed since I last looked at my watch.

Nevertheless, I am ready to allow that, though a feeling of tedium, or the contrary feeling of irritation at the rapidity of time, will linger for an appreciable interval and colour the retrospective estimate of time, this backward view is chiefly determined by other considerations.

As Wundt remarks, we have no sense of time's slowness during sleep, yet on waking we imagine that we have been dreaming for an immensely long period. This retrospective appreciation is determined by the number and the degree or intensity of the experiences, and, what comes very much to the same thing, by the amount of unlikeness, freshness, and discontinuity characterizing these experiences.

Time, as I have already hinted, is known under the form of a succession of different conscious experiences. Unbroken uniformity would give us no sense of time, because it would give us no conscious experience at all.

Strictly speaking, there is no such thing as a perfectly uniform mental state extending through an appreciable duration. In looking at one and the same object, even in listening to one and the same tone, I am in no two successive fractions of a second in exactly the same state of mind.

Slight alterations in the strength of the sensation,[123] in the degree or direction of attention, and in the composition of that penumbra of vague images which it calls up, occur at every distinguishable fraction of time.

This being so, it would seem to follow that the greater the number of clearly marked changes, and the more impressive and exciting these transitions, the fuller will be our sense of time. And this is borne out by individual reflection. When striking and deeply interesting events follow one another very rapidly, as when we are travelling, duration appears to swell out.

It is possible that such a succession of stirring experiences may beget a vague consciousness of time at each successive moment, and apart from retrospection, simply by force of the change. In other words, without our distinctly attending to time, a series of novel impressions might, by giving us the consciousness of change, make us dimly aware of the numerical richness of our experiences. But, however this be, there is no doubt that, in glancing back on such a succession of exciting transitions of mental condition, time appears to expand enormously, just as it does in looking back on our dream-experience, or that rapid series of intensified feelings which, according to De Quincey and others, is produced by certain narcotics.

The reason of this is plain. Such a type of successive experience offers to the retrospective imagination a large number of distinguishable points, and since this mode of estimating time depends, as we have seen, on the extent of the process of filling in, time will necessarily appear long in this case. On the other hand, when we have been engaged in very ordinary pursuits, in which few deeply interesting or exciting events have impressed themselves on memory, our retrospective picture will necessarily be very much of a blank, and consequently the duration of the period will seem to be short.

I observed that this retrospective appreciation of time depended on the degree of connection between the successive experiences. This condition is very much the same as the other just given, namely, the degree of uniformity of the experiences, since the more closely the successive stages of the experience are connected--as when, for example, we are going through our daily routine of work--the more quiet and unexciting will be the transition from each stage to its succeeding one. And on the other hand, all novelty of impression and exciting transition of experience clearly involves a want of connection. Wundt thinks the retrospective estimate of a connected series of experiences, such as those of our daily round of occupations, is defective just because the effort of attention, which precedes even an imaginative reproduction of an impression, so quickly accommodates itself in this case to each of the successive steps, whereas, when the experiences to be recalled are disconnected, the effort requires more time. In this way, the estimate of a past duration would be coloured by the sense of time accompanying the reproductive process itself. This may very likely be the case, yet I should be disposed to attach most importance to the number of distinguishable items of experience recalled.

Our representation of the position of a given event in the past is, as I have tried to show, determined by the movement of imagination in going back to it from the present. And this is the same thing as to say that it depends on our retrospective sense of the intervening s.p.a.ce. That is to say, the sense of distance in time, as in s.p.a.ce, is the recognition of a term to a movement. And just as the distance of an object will seem greater when there are many intervening objects affording points of measurement, than when there are none (as on the uniform surface of the sea), so the distance of an event will vary with the number of recognized intervening points.

The appreciation of the distance of an event in time does not, however, wholly depend on the character of this movement of imagination. Just as the apparent distance of a visible object depends _inter alia_ on the distinctness of the retinal impression, so the apparent temporal remoteness of a past event depends in part on the degree of intensity and clearness of the mnemonic image. This is seen even in the case of those images which we are able distinctly to localize in the time-perspective. For a series of exciting experiences intervening between the present and a past event appears not only _directly_ to add to our sense of distance by const.i.tuting an apparently long interval, but _indirectly_ to add to it by giving an unusual degree of faintness to the recalled image. An event preceding some unusually stirring series of experiences gets thrust out of consciousness by the very engrossing nature of the new experiences, and so tends to grow more faint and ghost-like than it would otherwise have done.

The full force of this circ.u.mstance is best seen in the fact that a very recent event, bringing with it a deep mental shock and a rapid stirring of wide tracts of feeling and thought, may get to look old in a marvellously short s.p.a.ce of time. An announcement of the loss of a dear friend, when sudden and deeply agitating, will seem remote even after an hour of such intense emotional experience. And the same twofold consideration probably explains the well-known fact that a year seems much shorter to the adult than to the child. The novel and comparatively exciting impressions of childhood tend to fill out time in retrospect, and also to throw back remote events into a dimly discernible region.

Now, this same circ.u.mstance, the degree of vividness or of faintness of the mnemonic image, is that which determines our idea of distance when the character of the intervening experiences produces no appreciable effect.[124] This is most strikingly ill.u.s.trated in those imperfect kinds of recollection in which we are unable to definitely localize the mnemonic image. To the consideration of these we will now turn.

B. _Indefinite Localization._

Speaking roughly and generally, we may say that the vividness of an image of memory decreases in proportion as the distance of the event increases. And this is the rule which we unconsciously apply in determining distance in time. Nevertheless, this rule gives us by no means an infallible criterion of distance. The very fact that different people so often dispute about the dates and the order of past events experienced in common, shows pretty plainly that images of the same age tend to arise in the mind with very unequal degrees of vividness.

Sometimes pictures of very remote incidents may suddenly present themselves to our minds with a singular degree of brightness and force.

And when this is the case, there is a disposition to think of them as near. If the relations of the event to other events preceding and succeeding it are not remembered, this momentary illusion will persist.

We have all heard persons exclaim, "It seems only yesterday," under the sense of nearness which accompanies a recollection of a remote event when vividly excited. The most familiar instance of such lively reproduction is the feeling which we experience on revisiting the scene of some memorable event. At such a time the past may return with something of the insistence of a present perceived reality. In pa.s.sing from place to place, in talking with others, and in reading, we are liable to the sudden return by hidden paths of a.s.sociation of images of incidents that had long seemed forgotten, and when they thus start up fresh and vigorous, away from their proper surroundings, they invariably induce a feeling of the propinquity of the events.

In many cases we cannot say why these particular images, long buried in oblivion, should thus suddenly regain so much vitality. There seems, indeed, to be almost as much that is arbitrary and capricious in the selection by memory of its vivid images as in the selection of its images as a whole; and, this being so, it is plain that we are greatly exposed to the risk of illusion from this source.

There is an opposite effect in the case of recent occurrences that, for some reason or another, have left but a faint impression on the memory; though this fact is not, perhaps, so familiar as the other. I met a friend, we will suppose, a few days since at my club, and we exchanged a few words. My mind was somewhat preoccupied at the time, and the occurrence did not stamp itself on my recollection. To-day I meet him again, and he reminds me of a promise I made him at the time. His reminder suffices to restore a dim image of the incident, but the fact of its dimness leads to the illusion that it really happened much longer ago, and it is only on my friend's strong a.s.surances, and on reasoning from other data that it must have occurred the day he mentions, that I am able to dismiss the illusion.

The most striking examples of the illusory effect of mere vividness, involving a complete detachment of the event from the prominent landmarks of the past, are afforded by public events which lie outside the narrower circle of our personal life, and which do not in the natural course of things become linked to any definitely localized points in the field of memory. These events may be very stirring and engrossing for the time, but in many cases they pa.s.s out of the mind just as suddenly as they entered it. We have no occasion to revert to them, and if by chance we are afterwards reminded of them, they are pretty certain to look too near, just because the fact of their having greatly interested us has served to render their images particularly vivid.

A curious instance of this illusory effect was supplied not long since by the case of the ex-detectives, the expiration of whose term of punishment (three years) served as an occasion for the newspapers to recall the event of their trial and conviction. The news that three years had elapsed since this well-remembered occurrence proved very startling to myself, and to a number of my friends, all of us agreeing that the event did not seem to be at more than a third of its real distance. More than one newspaper commented on the apparent rapidity of the time, and this shows pretty plainly that there was some cause at work, such as I have suggested, producing a common illusion.

I have treated of these illusions connected with the estimate of past time and the dating of past events as pa.s.sive illusions, not involving any active predisposition on the part of the imagination. At the same time, it is possible that error in these matters may occasionally depend on a present condition of the feelings and the imagination. It seems plain that since the apparent degree of remoteness of an event not distinctly localized in the past varies inversely as the degree of vividness of the mnemonic image, any conscious concentration of mind on a recollection will tend to bring it too near. In this way, then, an illusory propinquity may be given to a recalled event through a mere desire to dwell on it, or even a capricious wish to deceive one's self.

When, for example, old friends come together and talk over the days of yore, there is a gradual reinstatement of seemingly lost experiences, which often partakes of the character of a semi-voluntary process of self-delusion. Through the c.u.mulative effect of mutual reminder, incident after incident returns, adding something to the whole picture till it acquires a degree of completeness, coherence, and vividness that render it hardly distinguishable from a very recent experience. The process is like looking at a distant object through a field-gla.s.s.

Mistiness disappears, fresh details come into view, till we seem to ourselves to be almost within reach of the object.

Where the mind habitually goes back to some painful circ.u.mstance under the impulse of a morbid disposition to nurse regret, this momentary illusion may become recurring, and amount to a partial confusion of the near and the remote in our experience. An injury long brooded on seems at length a thing that continually moves forward as we move; it always presents itself to our memories as a very recent event. In states of insanity brought on by some great shock, we see this morbid tendency to resuscitate the dead past fully developed, and remote events and circ.u.mstances becoming confused with present ones.

On the other hand, in more healthy states of mind there presents itself an exactly opposite tendency, namely, an impulse of the will to banish whatever when recalled gives pain to the furthest conceivable regions of the past. Thus, when we have lost something we cherished dearly, and the recollection of it brings fruitless longing, we instinctively seek to expel the recollection from our minds. The very feeling that what has been can never again be, seems to induce this idea of a vast remoteness of the vanished reality. When, moreover, the lost object was fitted to call forth the emotion of reverence, the impulse to magnify the remoteness of the loss may not improbably be reinforced by the circ.u.mstance that everything belonging to the distant past is fitted on that account to excite a feeling akin to reverence. So, again, any rupture in our mental development may lead us to exaggerate the distance of some past portion of our experience. When we have broken with our former selves, either in the way of worsening or bettering, we tend to project these further into the past.

It is only when the sting of the recollection is removed, when, for example, the calling up of the image of a lost friend is no longer accompanied with the bitterness of futile longing, that a healthy mind ventures to nourish recollections of such remote events and to view these as part of its recent experiences. In this case the mnemonic image becomes transformed into a kind of present emotional possession, an element of that idealized and sublimated portion of our experience with which all imaginative persons fill up the emptiness of their actual lives, and to which the poet is wont to give an objective embodiment in his verse.