MEMORY IN DREAMS

The Apparent Rapidity of Thought in Dreams—This Phenomenon largely due to the Dream being a Description of a Picture—The Experience of Drowning Persons—The Sense of Time in Dreams—The Crumpling of Consciousness in Dreams—The Recovery of Lost Memories through the Relaxation of Attention—The Emergence in Dreams of Memories not known to Waking Life—The Recollection of Forgotten Languages in Sleep—The Perversions of Memory in Dreams—Paramnesic False Recollections—Hypnagogic Paramnesia—Dreams mistaken for Actual Events—The Phenomenon of Pseudo-Reminiscence—Its Relationship to Epilepsy—Its Prevalence especially among Imaginative and Nervously Exhausted Persons—The Theories put forward to Explain it—A Fatigue Product—Conditioned by Defective Attention and Apperception—Pseudo-Reminiscence a reversed Hallucination.

The peculiarities of memory in dreams—its defects, its aberrations, its excesses—have attracted attention ever since dreams began to be studied at all. It is not enough to assure ourselves that on awakening from a dream our memory of that dream may fairly be regarded as trustworthy so far as it extends. The characteristics of memory revealed within the reproduced dream have sometimes seemed so extraordinary as to be only explicable by the theory of supernatural intervention.

A problem which at one time greatly puzzled the scientific students of dreaming is furnished at the outset by the apparent abnormal rapidity of the dream process, the piling together in a brief space of time of a great number of combined memories. Stories were told of people who, when awakened by sounds or contacts which must have aroused them almost immediately, had yet experienced elaborate visions which could only have been excited by the stimulus which caused the awakening. The dream of Maury—who, when awakened by a portion of the bed cornice falling on his neck, imagined that he was living in the days of the Reign of Terror, and, after many adventures, was being guillotined—has become famous.[192]

It is unquestionably true that dreams are sometimes evoked by sensory stimuli which almost immediately awake the dreamer. But the supposition that this fairly common fact involves an extraordinary acceleration of the rapidity with which mental images are formed is due to a failure to comprehend the conditions under which psychic activity in sleep takes place. If the sleeper were wide awake, and were suddenly startled by a mysterious voice at the window or the door, he would arrive at a theory of the sound, and even form a plan of action, with at least as much rapidity as when the stimulus occurs during sleep. The difference is that in sleep the ordinary mental associations are more or less in abeyance, and the way is therefore easily open to new associations. These new associations, when we look back at them from the standpoint of waking life, seem to us so bizarre, so far-fetched, that we think it must have required a long time to imagine them. We fail to realise that, under the conditions of dream thought, they have come about as automatically and as instantaneously as the ordinary psychic concomitants of external stimulation in waking life. It must also be remembered that in all the cases in which the rapidity of the dream process has seemed so extraordinary, it has merely been a question of visual imagery, and it is obviously quite easy to see in an instant an elaborate picture or series of pictures which would take a long time to describe.[193] At the most the dreamer has merely seen a kind of cinematographic drama which has been condensed and run together in very much the way practised by the cinematographic artist, so that although the whole story seems to be shown in constant movement, in reality the action of hours is condensed into moments. Further, it has always to be borne in mind that, asleep as well as awake, intense emotion involves a loss of the sense of time. We say in a terrible crisis that moments seemed years, and when sleeping consciousness magnifies a trivial stimulation into the occasion of a great crisis the same effect is necessarily produced.

Exactly the same illusion is experienced by persons who are rescued from drowning, or other dangerous situations. It sometimes seems to them that their whole life has passed before them in vision during those brief moments. But careful investigation of some of these cases, notably by PiÉron, has shown that what really happened was that a scene from childhood, perhaps of some rather similar accident, came before the drowning man's mind and was followed by five, six, perhaps even ten or twelve momentary scenes from later life. When the time during which these scenes flashed through the mind was taken into account it was found that there had by no means been any remarkable mental rapidity.

Such considerations have now led most scientific investigators of dreaming to regard these problems of dream memory as settled. Woodworth's observations on the hypnagogic or half-waking state revealed no remarkable rapidity of mental processes. ClaviÈre showed by experiments with an alarm clock which struck twice with an interval of twenty-two seconds that speech dreams at all events take place merely with normal rapidity, or are even slightly slower than under waking conditions. The imagery of sleep, ClaviÈre concluded, is not more rapid than the imagery of waking life, though to the dreamer it may seem to last for hours or days. It is often slackened rather than accelerated, says PiÉron, who refers to the corresponding illusion under the influence of drugs like hashish, though in some cases he finds that there is really a slight acceleration. The illusion is simply due, Foucault thinks, to the dreamer's belief that the events of his dream occupy the same time as real events. This illusion of time, concludes Dr. Justine Tobolowska, in her Paris thesis on this subject, is simply the necessary and constant result of the form assumed by psychic life during sleep.[194]

If this peculiarity of memory in dreaming is not difficult to explain as a natural illusion, there are other and rarer characteristics of dream memory which are much more puzzling.

In attempting to unravel these, it is probable that, as in explaining the illusion of rapidity, we must always bear in mind the tendency of memory-groups in dreams to fall apart from their waking links of association, so well as the complementary tendency to form associations which in waking life would only be attained by a strained effort. Apperception, with the power it involves of combining and bringing to a focus all the various groups of memories bearing on the point in hand, is defective. The focus of conscious attention is contracted, and there is the curious and significant phenomenon that sleeping consciousness is occasionally unconscious of psychic elements which yet are present just outside it and thrusting imagery into its focus. The imagery becomes conscious, but its relation to the existing focus of consciousness is not consciously perceived. Such a psychic mechanism, as Freud and his disciples have shown, quite commonly appears in hysteria and obsessional neuroses when healthy normal consciousness is degraded to a pathological level resembling that which is normal in dreams.[195] In such a case the surface of sleeping consciousness is, as it were, crumpled up, and the concealed portion appears only at the end of the dream or not at all. A simple example may make this clear. In a dream I ask a lady if she knows the work of the poet Bau; she replies that she does not; then I see before me a paper having on it the name Baudelaire, clearly the name which should have been contained in my query.[196] In such a dream the crumpling and breaking of consciousness, at its very focus, is shown in the most unmistakable manner.[197] But many of the most remarkable dreams of dramatic dreamers are due to the same phenomenon, which in an intellectual form is exactly the phenomenon which always makes a dramatic situation effective. Robert Louis Stevenson was an abnormally vivid dreamer, and found the germ of some of the plots of his stories in his dreams; he has described one of his dreams in which the dreamer imagines he has committed a murder; the crime becomes known to a woman who, however, never denounces it; the murderer lives in terror, and cannot conceive why the woman prolongs his torture by this delay in giving him up to justice; only at the end of the dream comes the clue to the mystery, and the explanation of the woman's attitude, as she falls on her knees and cries: 'Do you not understand? I love you.'[198]

There is another and very interesting class of dreams in which we find not merely that some memory-groups disappear from consciousness or become merely latent, but also that other memory-groups, latent or even lost to waking consciousness, float into the focus of sleeping consciousness. In other words, we can remember in sleep what we have forgotten awake. We then have what is called the hypermnesia, the excessive or abnormal memory, of sleep.

There can be little doubt that the two processes—the sinking of some memory-groups and the emergence on the surface of other memory-groups which, so far as waking life is concerned, had apparently fallen to the depths and been drowned—are complementarily related to one another. We remember what we have forgotten because we forget what we remembered. The order of our waking impressions involves a certain tension, that is to say a certain attention, which holds them in our consciousness, and excludes any other order which might serve to bring lost memory-groups to sight. Sometimes we are conscious of a lost memory which is just outside consciousness, but which, with the existing order of our memory-groups, we cannot bring into consciousness. We have the missing name, the missing memory, at the tip of our tongue, we say, but we cannot quite catch it.[199] In dreams apperception is defective, the strain of conscious attention is relaxed, and the conditions are furnished under which new clues and strains may come into action and the missing name glide spontaneously into consciousness. Even the mere approach of sleep, with its accompanying relaxation of attention, may effect this end. Thus I was trying one day to recall the name of the unpleasant Chinese scent, patchouli. The name, though not usually unfamiliar, escaped me. At night, however, just before falling asleep, it spontaneously occurred to me. In the morning, when fully awake, I was again unable to recall it.

In such a case we see how waking consciousness is tense in a certain direction, which happens not to be that in which the desired thing is to be found. Attention under such circumstances impedes rather than aids recollection. In this particular case, I felt convinced that the name I wanted began with h, and thus my mind was intently directed towards a wrong quarter. But on the approach of sleep attention is automatically relaxed, and it is then possible for the forgotten word to slip in from its unexpected quarter. On these occasions it is by indirection that direction is found.[200]

It is interesting to observe that this same process of discovery due to the wider outlook of relaxed attention can take place, not only in sleep and the hypnagogic state, but also, subconsciously, in the fully waking state when the mind is occupied with some other subject. Thus in reading a MS., I came upon an illegible word which I was unable to identify, notwithstanding several guesses and careful scrutiny through a magnifying glass. I passed on, dismissing the subject from my mind. A quarter of an hour afterwards, when walking, and thinking of quite a different subject, I became conscious that the word 'ceremonial' had floated into the field of mental vision, and I at once realised that this was the unidentified word. The instance may be trivial, but no example could better show how the mind may continue to work subconsciously in one direction while consciously working in an entirely different direction.

In dreams, however, we can effect more than a mere recovery of memories which have temporarily escaped us, or the discovery of relationships which have eluded us. The dissociation of familiar memory-groups becomes so complete, the appearance of unfamiliar groups so eruptive, that we can remember things that have entirely and permanently sunk below the surface of waking consciousness, or even things which are so insignificant that they have never made any mark on waking consciousness at all. In this way, we may be said, in a certain sense, to remember things we never knew. The first dream which enabled me, some twenty years ago, to realise this hypermnesia of the mind in dreams[201] was the following unimportant but instructive case. I woke up recalling the chief items of a rather vivid dream: I had imagined myself in a large old house, where the furniture, though of good quality, was ancient, and the chairs threatened to give way as one sat on them. The place belonged to one Sir Peter Bryan, a hale old gentleman, who was accompanied by his son and grandson. There was a question of my buying the place from him, and I was very complimentary to the old gentleman's appearance of youthfulness, absurdly affecting not to know which was the grandfather and which the grandson. On awaking I said to myself that here was a purely imaginative dream, quite unsuggested by any definite experiences. But when I began to recall the trifling incidents of the previous day, and the things I had seen and read, I realised that that was far from being the case. So far from the dream having been a pure effort of imagination, I found that every minute item could be traced to some separate source, though none of them had the slightest resemblance to the dream as a whole. The name of Sir Peter Bryan alone completely baffled me; I could not even recall that I had at that time ever heard of any one called Bryan. I abandoned the search and made my notes of the dream and its sources. I had scarcely done so when I chanced to take up a volume of biographies of eccentric personages, which I had glanced through carelessly the day before. I found that it contained, among others, the lives of Lord Peterborough and George Bryan Brummel. I had certainly seen those names the day before; yet before I took up the book once again it would have been impossible for me to recall the exact name of Beau Brummel. It so happened that the forgotten memory which in this case re-emerged to sleeping consciousness, was a fact of no consequence to myself or any one else. But it furnishes the key to many dreams which have been of more serious import to the dreamers.

Since then I have been able to observe among my friends several instances of dreams containing veracious though often trivial circumstances unknown to the dreamer when awake, though on consideration it was found to be in the highest degree probable that they had come under his notice, and been forgotten, or not consciously observed. Thus a musical correspondent tells me he once dreamed of playing a piece of Rubinstein's in the presence of a friend who told him he had made a mistake in re-striking a tied note. In the morning he found the dream friend was correct. But up to then he had always repeated the note. Usually when the forgotten or unnoticed circumstance is trivial, it is of quite recent date. That it is not always very recent may be illustrated by a dream of my own. I dreamed that I was in Spain and about to rejoin some friends at a place which was called, I thought, Daraus, but on reaching the booking-office I could not remember whether the place I wanted to go to was called Daraus, Varaus, or Zaraus, all which places, it seemed to me, really existed. On awaking, I made a note of the dream, exactly as reproduced here, but was unable to recall any place, in Spain or elsewhere, corresponding to any of these names. The dream seemed merely to illustrate the familiar way in which a dream image perpetually shifts in a meaningless fashion at the focus of sleeping consciousness. The note was put away, and a few months later taken out again.[202] It was still equally impossible to me to recall any real name corresponding to the dream names. But on consulting the Spanish guide-books and railway time-tables, I found that, on the line between San Sebastian and Bilbao, there really is a little seaside resort, in a beautiful situation, called Zarauz, and I realised, moreover, that I had actually passed that station in the train two hundred and fifty days before the date of my dream.[203] I had no associations with this place, though I may have admired it at the time; in any case it vanished permanently from conscious memory, perhaps aided by the fatigue of a long night journey before entering Spain. Even sleeping memory, I may remark, only recovered it with an effort, for it is notable that the name was gradually approached by three successive attempts.[204]

A special form of lost or unconscious memories recurring in sleep is constituted by the cases in which people when asleep, or in a somnambulistic state, can speak languages which they have forgotten, or never consciously known, when awake. A simple instance, known to me, is furnished by a servant who had been taken to Paris for a few weeks six months before, but had never learned to speak a word of French, and whose mistress overheard her talking in her sleep, and repeating various French phrases, like 'Je ne sais pas, Monsieur'; she had certainly heard these phrases, though she maintained, when awake, that she was ignorant of them. Speaking in a language not consciously known, or xenoglossia, as it is now termed, occurs under various abnormal conditions, as well as in sleep, and is sometimes classed with the tendency which is found, especially under great religious excitement, to 'speak with tongues,' or to utter gibberish.[205] But in various sleep-like states it occurs as a true revival of forgotten memories, sometimes of memories which belong to childhood and in normal consciousness have been long overlaid and lost. On one occasion, by the bedside of a lady who was kept for a considerable period in a light condition of chloroform anaesthesia, the patient began to talk in an unfamiliar language which one of us recognised as Welsh; as a child, she afterwards owned, she had known Welsh, but had long since forgotten it.[206] A similar reproduction of lost memories occurs in the hypnotic state.

This psychic process, by which unconscious memories become conscious in dreams, is of considerable interest and importance because it lends itself to many delusions. Not only the ignorant and uncultured, but even well-trained and acute minds, are often so unskilled in mental analysis that they are quite unable to pierce beneath the phenomenon of conscious ignorance to the deeper fact of unconscious memory; they are completely baffled, or else they resort to the wildest hypotheses. This is illustrated by the following narrative received twelve years ago from a medical correspondent in Baltimore. 'Several years ago,' he writes, 'a friend made a social call at my house and in the course of conversation spoke very enthusiastically of Mascagni's Cavalleria Rusticana, the first performance of which in the United States he had attended a few nights previously. I had never even heard of the opera before, but that night I dreamed that I heard it performed. The dream was a very vivid one, so vivid that several times during the next day I found myself humming airs from the dream opera. Several evenings later I went to the theatre to see a comedy, and before the curtain rose the orchestra played a selection which I instantly recognised as part of my dream opera. I exclaimed to a lady who was with me: "That selection is from Cavalleria Rusticana." On inquiring of the leader of the orchestra such proved to be the case.' Now, at that period, shortly after the first appearance of Cavalleria Rusticana, portions of it had become extremely popular and were heard everywhere, by no means merely on the operatic stage. It was difficult not to have heard something of it. There cannot be the slightest doubt that my correspondent had heard not only the name but the music, though, writing at an interval of some years, he probably exaggerated the extent of his unconscious recollections. This seems the simple explanation of what to my correspondent was an inexplicable mystery. Other people, like the late Frederick Greenwood, not content to remain baffled, go further and regard such dreams as 'dreams of revelation,' as they also consider that class of dreams in which the dreamer works out the solution of a difficulty which he had vainly grappled with when awake.

This is a kind of dream which has occurred in all ages, and has at times been put down to divine interposition. Sixteen centuries ago Bishop Synesius of Ptolemais wrote that in his hunting days a dream revealed to him an idea for a trap which he successfully employed in snaring animals, and at the present time inventions made in dreams have been successfully patented. The Rev. Nehemiah Curnock, who lately succeeded in deciphering Wesley's Journal, has stated that an important missing clue to the cypher came to him in a dream. A friend of my own, an expert in chemistry, was not long since in frequent communication with a practical manufacturer, assisting him in his inventions by scientific advice. One day the manufacturer wrote to my friend asking if the latter had been thinking of him during the night, for he had been much puzzled by a difficulty, and during the night had seen a vision of my friend who explained the solution of the difficulty; in the morning the proposed solution proved successful. There was, however, no telepathic element in the case; the dreamer's solution was his own.

An interesting group of cases in this class is furnished by the dreams in which the dreamer, in opposition to his waking judgment, sees an acquaintance in whom he reposes trust acting in a manner unworthy of that trust, subsequent events proving that the estimate formed during sleep was sounder than that of waking life. Hawthorne (in his American Notebooks), Greenwood, Jewell, and others have recorded cases of this kind.

Various as these phenomena are, they fall into the same scheme. They all help to illustrate the fact that though on one side mental life in sleep is feeble and defective, on the other side it shows a tendency to vigorous excess. Sleep, as we know, involves a relaxation of tension, both physical and psychic; attention is no longer focused at a deliberately selected spot.[207] The voluntary field becomes narrower, but the involuntary field becomes extended. Thus it happens that the contents of our minds fall into a new order, an order which is often fantastic but, on the other hand, is sometimes a more natural and even a more rational order than that we attain in waking life. Our eyes close, our muscles grow slack, the reins fall from our hands. But it sometimes happens that the horse knows the road home even better than we know it ourselves.

Hypermnesia, or abnormally wide range of recollection, is not the only or the most common modification of memory during sleep. We find much more commonly, and indeed as one of the chief characteristics of sleep, an abnormally narrow range of recollection. We find, also, and perhaps as a result of that narrow range, paramnesia or perversion of memory. The best known form of paramnesia is that in which we have the illusion that the event which is at the moment happening to us has happened to us before.[208]

This form of paramnesia is common in dreams, though it is often so slightly pronounced that we either fail to recall it on awakening or attach no significance to it.[209] I dream, for instance, that I am walking along a path, along which, it seems to me, I have often walked before, and that the path skirts the lawn of a house by which stands a policeman whom, also, it seems to me, I have often seen there before; the policeman approaches me and says, 'You have come to see Mr. So-and-so, sir?' and thereupon I suddenly recollect, with some confusion, that I have come to see Mr. So-and-so, and I walk up to the door. Again, an author dreams that he sees a list of his own books with, at the head of them, one entitled 'The Book of Glory.' He could not recall writing it (and to waking consciousness the name was entirely unknown), but the only reflection he made in his dream was 'How stupid to have forgotten!' In this case there was evidently some resistance to the suggestion, which yet was quickly accepted. In all such dreams it seems that we are in a state of mental weakness associated with defective apperceptual control and undue suggestibility, very similar to the state found in some forms of confusional insanity or of precocious dementia.[210] Consciousness feebly slides down the path of least resistance; it accepts every suggestion; the objects presented to it seem things that it knew before, the things that are suggested to it to do seem things that it already wanted to do before. Paramnesia, thus regarded, seems simply a natural outcome of a state of consciousness temporarily depressed below its normal standard of vigour.

It must be remembered that the suggestibility of sleeping consciousness varies in degree, and in the face of serious improbabilities there is often a considerable amount of resistance, just as the hypnotised person seriously resists the suggestions that fundamentally outrage his nature. But some degree of suggestibility, some tendency to regard the things that come before us in dreams as familiar—in other words, as things that have happened to us before—is not merely a natural result of defective apperception, but one of the very conditions of dreaming. It enables us to carry on our dreams; without it their progress would be fatally inhibited by doubt, uncertainty, and struggle. So it is, perhaps, that in all dreaming, or at all events in certain stages of sleeping consciousness, we are liable to fall into a state of pseudo-reminiscence.

It is an interesting and highly significant fact that this paramnesic delusion of our dreams—the feeling that the thing that is happening to us is the thing that has happened to us before or that might happen to us again—tends to persist in the hypnagogic (or hypnopompic) stage immediately following sleep. When we have half awakened from a dream and are just able to realise that it was a dream, that dream constantly tends to appear in a more plausible or probable light than is possible a few moments later when we are fully awake.[211]

The first experience which enabled me clearly to realise this phenomenon, and its probable explanation, occurred many years ago. About the middle of the night I had a very vivid dream, in which I imagined that two friends—a gentleman and his daughter—with a certain Lord Chesterfield (I had lately been reading the Letters of the famous Lord Chesterfield), were together at a hotel, that they were playing with weapons, that the lady accidentally killed or wounded Lord Chesterfield, and that she then changed clothes with him with the object of escaping, and avoiding discovery which would somehow be dangerous. I was informed of the matter, and was much concerned. I awoke, and my first thought was that I had just had a curious dream which I must not forget in the morning. But then I seemed to remember that it was a real and familiar event. This second thought lulled my mental activity, and I went to sleep again. In the morning I was able to recall the main points in my dream, and my thoughts on awaking from it.

Since then I have given attention to the point, and I have found on recalling my half-waking consciousness after dreams that, while it is doubtless rare to catch the assertion 'That really occurred,' it is less rare to catch the vague assertion, 'That is the kind of thing that does occur.' I find that this latter impression appears, like the former, after vivid dreams which contain no physical impossibility, but which the full waking consciousness refuses to recognise as among the things that are probable. As an example quite unlike that just recorded, I may mention a dream in which I imagined that I was proving the frequency of local intermarriage by noting in directories the frequency of the presence of people of the same name in neighbouring towns and villages. On half-awaking I still believed that I had actually been engaged in such a task—that is, either that the dream was real or that it referred to a real event—and it was not until I was sufficiently awake to recognise the fallacy of such a method of investigation that I realised that it was purely a dream.

This phenomenon has long been known, although its significance has not been perceived. Brierre de Boismont pointed out that certain vivid dreams are not recognised as dreams, but are mistaken for reality after waking, though he scarcely recognised the normal limitation of this mistake to the hypnagogic state. Moll compared such dreams, thus continued into waking life, to continuative post-hypnotic suggestions. Sully mentioned awaking from dreams which 'still wear the aspect of old acquaintances, so that for the moment I think they are waking realities.'[212] Colegrove, in his study of memory, recorded many cases in which young people mistook their dreams for actual events.[213]

This persistence of the memory illusion of sleep into the subsequent hypnagogic state is obviously related to the allied persistence, more occasionally found, of the visual, auditory, and other sensory hallucinations of sleep into the hypnagogic state.[214] Visions thus seen persisting from dreams for a few moments into waking life are often very baffling and disturbing, as has already been pointed out, to ignorant and untrained people. Such visions may occur in the hypnagogic state, even when there has been no conscious precedent dream, and it is indeed probable, as Parish has argued, that it is precisely in the hypnagogic state, the narthex of the church of dreams, as I may term it, that hallucinations are most liable to occur. That illusions may momentarily occur in this state is obvious; thus falling asleep for a few minutes when seated before a black hollow smouldering fire, with red ashes at the bottom, I awake with the illusion that I see a curtain on fire, and have already leaned forward to snatch it away before I realise my mistake.

Under normal conditions, the liability of a dream memory to be mistaken for an actual event seems to be greater when an interval has elapsed before the dream is remembered, such an interval making it difficult to distinguish one class of memories from the other, provided the dream has been of a plausible character. Thus Professor NÄcke has recorded that his wife dreamed that an acquaintance, an old lady, had called at the house; this dream was apparently forgotten until forty or fifty hours afterwards when, on passing the old lady's house, it was recalled, and the dreamer was only with much difficulty convinced that the dream was not an actual occurrence. When we are concerned with memories of childhood, it not infrequently happens that we cannot distinguish with absolute certainty between real occurrences and what may possibly have been dreams.

In normal physical and mental health, however, it seems rare for the hallucinatory influence of dreams to extend beyond the hypnagogic state, but any impairment of the bodily health generally, and of the brain in particular, may extend this confusion. Thus in a case of heart disease terminating fatally, the patient, though in health he was by no means visionary or impressionable, became liable during sleep in the day-time to dreams of an entirely reasonable character which he had great difficulty in distinguishing from the real facts of life, never feeling sure what had actually happened, and what had been only a dream. In disordered cerebral and nervous conditions the same illusion becomes still more marked. This is notably the case in hysteria. In some forms of insanity, as many alienists have shown, this mistake is sometimes permanent and the dream may become an integral and persistent part of waking life. At this point, however, we leave the normal world of dreams and enter the sphere of pathology.

In the normal persistence of the dream illusion into the hypnagogic state with which we are here concerned, the dream usually presents a possible, though, it may be, highly improbable event. The half-waking or hypnagogic intelligence seems to be deceived by this element of life-like possibility. Consequently a fallacy of perception takes place strictly comparable to the fallacious perception which, in the case of an external sensation, we call an illusion. In the ordinary illusion an externally excited sensation of one kind is mistaken for an externally excited sensation of another kind. In this case a centrally excited sensation of one order (dream image) is mistaken for a centrally excited sensation of another order (memory). The phenomenon is, therefore, a mental illusion belonging to the group of false memories, and it may be termed hypnagogic paramnesia.

The process seems to have a certain interest, and it may throw light on some rather obscure phenomena. When we are able to recall a vivid dream, usually a fairly probable dream, with no idea as to when it was dreamed, and thus find ourselves in possession of experiences of which we cannot certainly say that they happened in waking life or in dream life, it seems probable that this hypnagogic paramnesia has come into action; the half-waking consciousness dismisses the vivid and life-like dream as an old and familiar experience, shunting it off into temporary forgetfulness, unless some accident again brings it into consciousness with, as it were, a fragment of that wrong label still sticking to it. Such a paramnesic process may thus also help to account for the mighty part which, as so many thinkers from Lucretius onwards have seen, dreams have played in moulding human action and human belief. It is a means whereby waking life and dream life are brought to an apparently common level.

By hypnagogic paramnesia I mean a false memory occurring in the ante-chamber of sleep, but not necessarily before sleep. Myers's invention of the word 'hypnopompic' seems scarcely necessary even for pedantic reasons. I take the condition of consciousness to be almost the same whether the sleep is coming on or passing away. In the Chesterfield dream it is indeed impossible to say whether the phenomenon is 'hypnagogic' or 'hypnopompic'; in such a case the twilight consciousness is as much conditioned by the sleep that is passing away as by the sleep that is coming on.

If this memory illusion of the half-waking state may be regarded as a variety of paramnesia, a new horizon is opened out to us. May not the hypnagogic variety throw light on the general phenomenon of paramnesia which has led to so many strange and complicated theories? I think it may.

Paramnesia, as we have seen, is the psychologist's name for a hallucination of memory which is sometimes called 'pseudo-reminiscence,' and by medical writers (who especially associate it with epilepsy) regarded as a symptom of 'dreamy state,'[215] while by French authors it is often termed 'false recognition' or 'sensation du dÉjÀ vu.' Dickens, who seems himself to have experienced it, thus describes it in David Copperfield: 'We have all some experience of a feeling that comes over us occasionally, of what we are saying and doing having been said or done before, in a remote time, of having been surrounded, dim ages ago, by the same faces, objects, and circumstances, of our knowing perfectly what will be said next, as if we suddenly remembered it.' Sometimes it seems that this previous occurrence can only have taken place in a previous existence,[216] whence we probably have, as St. Augustine seems first to have suggested, the origin of the idea of metempsychosis, of the transmigration of souls; sometimes it seems to have happened before in a dream; sometimes the subject of the experience is totally baffled in the attempt to account for the feeling of familiarity which has overtaken him. In any case he is liable to an emotion of distress which would scarcely be caused by the coincidence of resemblance with a real previous experience.[217]

Paramnesia of this kind is known, according to the observations of Lalande,[218] to thirty people in a hundred, and Heymans found it in a considerable proportion of students of both sexes. Such estimates are probably too high if we take into consideration the general population. This experience seems, as Dugas and others have noted,[219] to affect educated people, and notably people of more than average intellect, who use their brains much, especially in artistic and emotional work, to a very much greater degree than the ignorant and phlegmatic manual worker.[220] Dickens has already been mentioned; many other notable writers have referred to this or some allied feeling, stating that they had experienced it, and Sir James Crichton-Browne brings forward a number of passages from the poets in evidence of their familiarity with such phenomena.[221] Shelley (who appears on at least two occasions to have experienced hallucinations also) underwent what may be regarded as an experience of paramnesia (described in his Speculations on Metaphysics) which is of interest in the present connection because it brings this phenomenon into relation with dreams. He was walking with a friend in the neighbourhood of Oxford, when he suddenly turned the corner of a country lane and saw 'a common scene' of a windmill, etc., which, it immediately seemed to him, he recollected having seen before in a dream of long ago. Five years afterwards he was so agitated in writing this down that he could not finish the account. The real resemblance of 'a common scene' with a similar dream scene, even supposing it could be recollected when the two experiences were separated by a long interval, would scarcely be a coincidence likely to cause agitation. The emotion aroused seems to mark the experience as belonging to the class of paramnesic illusions which so often make a peculiarly vivid impression on those to whom they occur.

A great many theories have been put forward by psychologists and others to account for this paramnesic phenomenon. The most ancient explanation, long anterior to the beginnings of scientific psychology, was the theory that the occurrence which, as it now happens, strikes us as so overwhelmingly familiar had actually occurred to us in a previous existence long ages before; thus Pythagoras, according to the ancient story, when he visited the temple of Juno at Argos recognised the shield he had worn ages before when he was Euphorbus and fought with Menelaus in the Trojan war. A much more recent theory runs to the opposite extreme and claims that all or nearly all these cases of recognition indicate a real but confused reminiscence of past events in our present life, dim recollections which the subject is unable definitely to locate. This is the explanation largely relied on by Ribot, Jessen, Sander, Sully, Burnham, and many others. It was perhaps largely due to ignorance of the phenomenon; Ribot, when he wrote his book on the diseases of memory, considered that only three or four cases had been recorded, for an abnormal phenomenon always seems rare until it is recognised and definitely searched for. Undoubtedly, this theory will explain a considerable proportion of cases, but not really typical cases in which the subject has an overwhelming conviction that even the minute details of the present experience have been experienced before. We may read a new poem with a vague sense of familiarity, but such an experience never puts on a really paramnesic character, for we quickly realise that it is explainable by the fact that the writer of the poem has fallen under the influence of some greater master. The only experience I can personally speak of as at all approaching true paramnesia occurred on visiting the ruins of Pevensey Castle many years ago. On going up the slope towards the ivy-covered ruins, bathed in bright sunlight, I experienced a strange and abiding sense of familiarity with the scene. Three theories might account for this experience (for I refrain from including the Pythagorean theory that I experienced a reminiscence of the experience of a possible ancestor coming from across the Thames to the assistance of Harold against William the Conqueror at this spot): (1) that it was a case of true paramnesia; (2) that I had been taken to the spot as a child; (3) that the view was included among a series of coloured stereoscopic pictures with which I was familiar as a child, and which certainly contained similar scenes. I incline to this last explanation. Here, as elsewhere, there are no keys which will unlock all doors.

A modification of the theory that the pseudo-reminiscence is an unrecognised real reminiscence is furnished by Grasset, who considers that the phenomenon is due to a subconscious impression previously received, but only reaching consciousness under the influence of the new similar impression. This theory would include the revival of dream images, and is therefore related to the theory of Lapie and MÉrÉ, according to which the feeling of many of these subjects that what they now experience had happened before in a dream is the correct explanation of the phenomenon.[222]

We enter on a different class of explanations with the early theory of Wigan that such cases are due to the duality of the brain, the two hemispheres not acting quite simultaneously. This is a somewhat crude conception, though it may seem approximately on the lines of more recent theories. The theory of the duplex brain, each hemisphere being supposed capable of acting independently, was at one time invoked to explain many phenomena, but it is no longer regarded as tenable.[223]

We may dismiss these theories, which have been effectively criticised by others, and revert to our clue in the sleeping and hypnagogic state. The hypnagogic state is a transition between waking and sleeping. It is thus a condition of mental feebleness and suggestibility doubtless correlated with a condition of irregular brain anaemia. A plausible suggestion under such conditions is too readily accepted. Does ordinary paramnesia occur under similar conditions of mental feebleness and suggestibility? It is rare to find descriptions of paramnesic experiences by scientific observers who are alive to the importance of accurately recording all the conditions, but there is some reason to think that paramnesia does occur in states produced by excitement, exhaustion, and allied causes. The earliest case of paramnesia recorded in detail by a trained observer is that described by Wigan as occurring to himself at the funeral of the Princess Charlotte. He had passed several disturbed nights previous to the ceremony, with almost complete deprivation of rest on the night immediately preceding; he was suffering from grief as well as from exhaustion from want of food; he had been standing for four hours, and would have fainted on taking his place by the coffin if it had not been for the excitement of the occasion. When the music ceased the coffin slowly sank in absolute silence, broken by an outburst of grief from the bereaved husband. 'In an instant,' Wigan proceeds, 'I felt not merely an impression, but a conviction, that I had seen the whole scene before on some former occasion.' Such a condition may fairly be regarded as an artificial reproduction, by means of emotion, excitement, and exhaustion, of the condition which occurs simply and naturally in sleep or on its hypnagogic borderland.

The frequency—if it may be taken to be a fact—of the occurrence of pseudo-reminiscence in epileptics, noted by various medical observers, whether at the onset of the fit or independently of any obvious muscular convulsion, may be significant in this connection. There is no good reason to suppose that pseudo-reminiscence has a true relation to epilepsy, and still less that it necessarily constitutes a minor epileptic paroxysm. But the special sleep-like condition of contracted cerebral circulation in epilepsy renders it favourable to paramnesia as well as to hallucinatory phenomena.[224]

Independently of epilepsy, any condition of temporary and perhaps chronic nervous exhaustion may produce, or at all events predispose to, the paramnesic delusion of recognising present experiences as familiar. Thus Rosenbach has recorded the case of a sane and healthy man, who, after severe mental labour, followed by sleeplessness, seemed to know all the people he met in the street, though on close examination he found he was mistaken.[225] Such a condition may even be almost congenital. Thus of Anna Kingsford, who was of highly strung and neurotic disposition, we are told that, as a child, 'all that she read struck her as already familiar to her, so that she seemed to herself to be recovering old recollections rather than acquiring fresh knowledge.'[226]

It is noteworthy that artificial anaesthesia by drugs which produce an abnormal sleep also favours paramnesia. Thus Sir William Ramsay[227] has stated that when, under an anaesthetic, he heard a slight noise in the street, 'I not merely knew that it had happened before, but I could have predicted that it would happen at that very moment.'

In all these conditions we appear to be in the presence of an enfeebled, excited, and impaired state of consciousness approximating to the true confusion of dream consciousness. It seems as if externally aroused sensations in such cases are received by the exhausted cerebral centres in so blurred a form that an illusion takes place, and they are mistaken for internally excited sensations, for memories.

That paramnesia is a fatigue product—even though often a product of nervous hyperaesthesia—is indicated by the statements of many who have described it. Anjel long ago emphasised this fatigue, and Bonatelli, also at an early period, found that illusions of memory were specially liable to occur in states of unusual nervous irritability. During recent years this characteristic of paramnesia has been more and more frequently recognised. Bernard Leroy, who devoted a lengthy and important Paris thesis to pseudo-reminiscence,[228] showed that a certain proportion of cases indicated the presence of fatigue or distraction. Heymans found that it was in the evening, when his subjects were in a passive condition, tired, exhausted, or engaged in uncongenial work, that they were most liable to the experience.[229] FÉrÉ brought forward a case in which, as he pointed out, pseudo-reminiscence in a healthy man, convalescent from influenza, was associated with fatigue and disappeared with it.[230] Dromard and AlbÈs declare that pseudo-reminiscence is 'a phenomenon of exhaustion,' and one of them makes the significant statement: 'I become more easily the prey of this illusion when, by chance and without thinking of it, I simultaneously apply my attention to an external object and an internal thought.'[231] Dugas, again, considers that all the various forms of paramnesia have 'one common character, which is that they occur as the result of prolonged or intense fatigue';[232] he adds that most of the cases of paramnesia he has noted in young people during fifteen years coincided with periods of anaemia and nervous weakness.

It is not, however, necessary to believe that fatigue, in the ordinary sense of the word, whether physical or mental, is the invariable accompaniment of paramnesia. If it is the presence of a condition resembling that of sleep or the hypnagogic state which predisposes to the experience, that condition may be produced by other circumstances. Distraction, excited hyperaesthesia simulating increased power, and various chronic psychic states due to a highly-strung or over-strained nervous system may all tend in the same direction, even though no sense of exhaustion is felt.[233] This is doubtless why it is that so many poets, novelists, and other men of strenuous intellectual aptitude are liable to this experience.

It has been argued by some who admit that there is often an element of fatigue in paramnesia,[234] that the real cause of the false memory is an abnormal celerity of perception, perhaps due to hyperaesthesia. The scene would thus be perceived so quickly that the subject concludes that he must have had this experience before. That the subject often has a feeling of unusual rapidity of perception may very well be admitted. But there is no reason whatever to suppose that the perception actually is received with any such unusual rapidity. The probabilities are in the other direction. We know that many influences (such as drugs like alcohol) which produce a feeling of heightened and quickened perceptions really have a slowing and dulling effect, in the same way as the wise and beautiful things we utter in dreams are usually found on awaking to be commonplace, if not meaningless. There is no evidence to show that paramnesia is accompanied by a real heightening of perception, while, as we have seen, a broad survey of the facts makes it more reasonable to suppose that we have, on the contrary, a sudden fall towards the dream state, a state in which, as TissiÉ and others have pointed out, there are many stages.

It must be remembered in this connection that in the hypnagogic and other states related to sleep we are not able to estimate time conditions consciously, though, as the frequent ability to wake at fixed moments indicates, we may do so subconsciously. Time is long, short, or non-existent in dream-like states. This is always true of the onset of the hypnagogic state. When I am suddenly awakened at night by a voice or a bell or other stimulus, I often find it very difficult to say whether I was or was not already awake, and have frequently replied, when so awakened, that I was already awake. That is an illusion, as is shown by the frequency with which elderly people who fall asleep in the day time, will declare, though they may have been snoring a moment before, that they have never been asleep. By a somewhat similar paramnesic illusion we can never fix the exact moment when we awake. When we become conscious that we are awake it always seems to us that we are already awake, awake for an indefinite time, and not that we have just awakened. If I had to register the exact moment I awake in the morning I should usually feel that I was considerably late in making the observation. It seems that the imperfect hypnagogic consciousness projects itself behind. At the first onset, consciousness is not sufficiently developed to be able to realise that it is beginning, and when it becomes sufficiently developed to make such a statement the moment when it can be correctly made is already past. Consciousness is only able to assert that it has been continuing for an indefinite time. And that assertion involves a paramnesic illusion of putting back a present experience into the past, analogous to the illusion of pseudo-reminiscence.[235]

If we realise these characteristics of paramnesia we can scarcely fail to conclude that we are concerned here with illusions which, while they fall within the sphere of memory, are largely conditioned by the whole psychic condition. As in dreams, it is inattention, failure of apperception, defective association of the mental contents, which make the paramnesia possible. Paramnesia is, as FouillÉe has said, a kind of diplopia or seeing double in the mental field. 'I have the impression,' says one of the writers on this subject who himself experiences the sensation, 'that the present reality has a double.' Actual double vision is due to the failure of that muscular co-ordination which, as Ribot and others have insisted, is of the very essence of attention. This wider psychic basis on which paramnesia rests has of late been recognised by several psychologists. Thus LÉon-Kindberg states that in paramnesia there is an absence of mental attention, of the effort of synthesis necessary to grasp an actual occurrence, which is, therefore, perceived with the same facility as a memory not requiring synthesis, with the resulting illusion that it is a memory.[236] Ballet, again, regards paramnesia as a transitory or permanent psychasthenic state, due to dissociation.[237] Dugas, also, who has repeatedly returned to this subject during many years, in his latest contributions attaches primary importance to this broader factor of paramnesia. In analysing memory, he says, there is an element which, though often overlooked, is capital: the recognition of a state of consciousness not merely as passed, but as bound up with our own personal past; when that synthetic function ceases to be accomplished, or is only accomplished defectively, then memory is lacking or perverted. Nervous weakness, he proceeds, produces failure of attention, the inhibitory power of attention being no longer exerted, and the psychic elements fall back to anarchy. Now many psychic states, such as sensations, recollections, and images, differ from each other less by their substance than by the way in which the mind takes hold of and apprehends them. The mind seizes a sensation with a stronger grasp than a recollection, and a recollection with a stronger grasp than an image. When attention is relaxed the line of demarcation between these psychic states tends to be effaced; the sensation becomes vague and floating like the recollection and the image, while the recollection and the image, on the contrary, become objective and acquire something of the brilliance and relief of the sensation. The very same cause—enfeeblement of attention—thus produces opposite effects, on the one side raising the tone, on the other lowering it, so that states of mind which are ordinarily distinct tend to be approximated and confused, as we may observe in the hypnagogic condition.[238]

Although Dugas makes no reference to Janet, it is not difficult to see that he has assimilated some of the views of that distinguished investigator of psychic mysteries. Janet, as we know, in various morbid psychic conditions, attaches great explanatory force to the individual's loss of hold, through psychic weakness, of his own personality, and to the diminished sense of reality and even depersonalisation thence ensuing. It so happens that Janet himself has set forth a theory of pseudo-reminiscence which is characteristic of his own attitude, and also harmonises with the wider outlook which now marks the attempts to explain these perversions of memory. Janet declares that pseudo-reminiscence is a negative phenomenon and belongs to a group in which various other feelings of diminished sense of reality belong. These people all say in effect: 'It seems to me that these things are not real; it seems to me that these events are not actual or present.' The essence of this form of paramnesia is thus more a negation of the present than an affirmation of the past. 'The function of adaptation to the present moment,' Janet remarks, 'is the most complicated and the most recent of all. The function of the real is the most elevated and the most difficult of all cerebral functions.' Under various influences there is a diminution of nervous and psychic tension, and such suppression of the high tension of the mind leaves only the lower functions subsisting. When that fall of tension is rapid, there may be a crisis of which pseudo-reminiscence is one of the symptoms.[239] Janet would thus place pseudo-reminiscence among the manifestations of psychasthenia, though he leaves untouched the difficult question of its precise mechanism.

The most comprehensive attempt to explain the mystery of paramnesia in recent years is certainly that made in an elaborately eclectic study by one of the most distinguished of living French thinkers, Professor Bergson.[240] He first casts a glance over what he considers the two main groups of explanations of this puzzling phenomenon: (1) those, advocated by Ribot, FouillÉe, Lalande, Arnaud, PiÉron, Myers, etc., which involve the more or less simultaneous existence in consciousness of two images, of which one is the reproduction of the other; (2) those advocated by Janet, Heymans, LÉon-Kindberg, Dromard and AlbÈs, etc., which insist on the lower mental tone, the diminished attention, the lack of synthetising power, which mark the condition in which paramnesia occurs. Bergson is quite ready to accept the principles of both these groups of explanations, and to combine them. But, he argues, to understand the phenomenon adequately, we must go deeper; we must analyse the normal mechanism of memory. And he finds, if we do this, that not merely the moment of a paramnesic illusion, but every moment of our life, offers two aspects, actual and virtual, perception on one side, and memory on the other. The moment itself, indeed, consists of such a scission, for it is always moving, always a fleeting boundary between the immediate past and the immediate future, and would be a mere abstraction if it were not 'precisely the mobile mirror which ceaselessly reflects perception in recollection.' When the matter is thus regarded a recollection is seen to be, in reality, not something which has been, but something which is, proceeding pari passu with the perception it reproduces. It is a recollection of the moment taking place at that moment. Belonging to the past as regards its form, it belongs to the present as regards its matter. It is recollection of the present. Now this is exactly the state in which the paramnesic person consciously finds himself, and the only problem before us, therefore, is to ascertain why every one at every moment is not conscious of the same experience. Bergson replies that nothing is more useless for present action than the recollection of the present. It has nothing to tell us; we hold the real object, and to give up that for its recollection would be to sacrifice the substance to the shadow. Therefore we obstinately and persistently turn away from the recollection of the present. It emerges consciously only under the influence of some abnormal or pathological disturbance of attention. Paramnesia is an anomaly of this kind, and it is due to a temporary enfeeblement of the general attention to life, a momentary arrest of the forward movement of consciousness. 'False recognition,' Bergson concludes, 'may thus be regarded as the most inoffensive form of inattention to life. It seems to result from the combined play of perception and memory given up to their own energy. It would take place at every moment if it were not that will, ceaselessly directed towards action, prevents the present from folding in on itself by pushing it indefinitely into the future.'

So far as my own explanation is concerned, it will be seen that I still place weight on the general condition of temporary or chronic nervous fatigue as the soil on which paramnesia arises—a belief now accepted by most psychologists[241]—and that I think we must search for the clue to the mechanism of the illusion in those dreaming and hypnagogic states in which it most often occurs. As regards a definite explanation of the mechanism we must, in the face of so many ingenious and complicated theories, perhaps still await more general agreement.[242] What I have suggested, and am still inclined to maintain, is that the psychic enfeeblement, temporary or chronic, which is the general preliminary condition of paramnesia, whether or not there is any subjective sensation of increased power, may account for the paramnesia by bringing an externally aroused perception down to a lower and fainter stage on which it is on a level with an internally aroused perception—a memory. Just as in hypnagogic paramnesia the vivid and life-like dream, or internal impression, is raised to the class of memories, and becomes the shadow of a real experience, so in waking paramnesia the external impression is lowered to the same class. Perception is alike dulled in each case, and the immediate experience follows the line of least resistance—this time too carelessly or too prematurely—to join the great bulk of our experiences.

We thus realise how it is that that doubling of experience occurs. The mind has for the moment become flaccid and enfeebled; its loosened texture has, as it were, abnormally enlarged the meshes in which sensations are caught and sifted, so that they run through too easily. In other words, they are not properly apperceived. To use a crude simile, it is as though we poured water into a sieve. The impressions of the world which are actual sensations as they strike the relaxed psychic meshwork are instantaneously passed through to become memories, and we see them in both forms at the same moment, and are unable to distinguish one from the other.

In sleep, and in the hypnagogic state, as in hypnosis, we accept a suggestion, with or without a struggle. In the waking paramnesic state we seem to find, in a slighter stage of a like condition, the same process in a reversed form. Instead of accepting a representation as an actual present fact, we accept the actual present fact as merely a representation. The centres of perception are in such a state of exhaustion and disorder that they receive an actual external sensation in the feebler shape of a representation. The actual fact becomes merely a suggestion of far distant things. It reaches consciousness in the enfeebled shape of an old memory—

Paramnesia is thus an internal hallucination, a reversed hallucination, it is true, but while so reversed, the stream of consciousness is still following the line of least resistance.

It is along some such lines as these, it seems to me, that we may best attempt to explain the phenomena of paramnesia, phenomena which are of no little interest since, in earlier stages of culture, they may well have had a real influence on belief, suggesting to primitive man that he had somehow had wider experiences than he knew of, and that, as Wordsworth put it, he trailed clouds of glory behind him.