1911 Encyclopædia Britannica/Dream

From Wikisource
Jump to navigation Jump to search

DREAM (from a root dreug, connected with Germ. trügen, to deceive), the state of consciousness during sleep; it may also be defined as a hallucination or illusion peculiarly associated with the condition of sleep, but not necessarily confined to that state. In sleep the withdrawal of the mind from the external world is more complete and the objectivity of the dream images is usually unquestioned, whereas in the waking state the hallucination is usually recognized as such; we may, however, be conscious that we are dreaming, and thus in a measure be aware of the hallucinatory character of our percepts. The physiological nature of sleep (q.v.; see also Muscle and Nerve) and of dreaming is obscure. As a rule the control over the voluntary muscles in dreams is slight; the sleep-walker is the exception and not the rule, and the motor activity represented in the dream is seldom realized in practice, largely, no doubt, because we are ignorant, under these circumstances, of the spatial relations of our bodies. Among the psychological problems raised by dreams are the condition of attention, which is variously regarded as altogether absent or as fixed, the extent of mental control, and the relation of ideas and motor impulses. There is present in all dreams a certain amount of dissociation of consciousness, or of obstructed association, which may manifest itself in the preliminary stage of drowsiness by such phenomena as the apparent transformation or inversion of the words of a book. We may distinguish two types of dreams, (a) representative or centrally initiated, (b) presentative or due to the stimulation of the end organs of sense. In both cases, the dream having once been initiated, we are concerned with a process of reasoning, i.e. the combination of ideas suggested by resemblances or other associative elements. The false reasoning of dreams is due in the first place to the absence, to a large extent, of the memory elements on which our ordinary reasoning depends, and, secondly, to the absence of sensory elements.

Objectivity of Dreams.—In waking life we distinguish ideas or mental images from real objects by the fact that we are able under normal circumstances to dismiss the former at will. In sleep, on the other hand, we have, in the first place, no real objects with which to compare the images, which therefore take on a character of reality comparable to the hallucination of waking life; moreover, powers of visualization and other faculties are enhanced in sleep, so that the strength of dream images considerably exceeds those of the mental images of the ordinary man; changes in powers of attention, volition and memory help to increase the hallucinatory force of the dream. In the second place, the ideas of our dreams are presented in the form of images, which we are unable to dismiss; we therefore mistake them for realities, exactly as the sufferer from delirium tremens in waking life is apt to regard his phantoms as real.

Relations of Dreaming and Sleep.—It has been maintained by Hamilton and others (see below, Modern Views) that dreams invariably accompany sleep, and that we always find ourselves dreaming when we are awakened. But even if it were true that dreams were invariably experienced at the moment of waking, this would not by any means establish the invariable concomitance of dreams and sleep of all sorts; at most it would show that imperfect sleep is a condition of dreaming; in the same way, dreams before wakening, known to have taken place either from the recollection of the dreamer or from the observation of another person, may clearly be due to imperfect wakening, followed by a deepening of sleep. It is, however, by no means true that awakening from sleep is invariably accompanied by a dream; in considering the question it must be recollected that it is complicated by the common experience of very rapid forgetfulness of even a vivid and complicated dream, only the fact of having dreamt remaining in the memory; it is clear that amnesia may go so far that even the fact of dreaming may be forgotten. On the whole, however, there appear to be no good grounds for the assertion that we always dream when we are asleep. On the other hand, there is no proof that partial awakening is a necessary condition of dreaming.

Representative Dreams.—Centrally initiated dreams may be due to a kind of automatic excitation of the cerebral regions, especially in the case of those clearly arising from the occupations or sensations of the day or the hours immediately preceding the dream. To the same cause we may attribute the recalling of images apparently long since forgotten. Some of these revivals of memory may be due to the fact that links of association which are insufficient to restore an idea to consciousness in the waking state may suffice to do so in sleep. Just as a good visualizer in his waking moments may call up an object never clearly seen and yet distinguish the parts, so in sleep, as L. F. A. Maury (1817–1892) and others have shown, an image may be more distinct in a dream than it was when originally presented (see also below, Memory).

Presentative Dreams.—The dreams due to real sensations, more or less metamorphosed, may arise (a) from the states of the internal organs, (b) from muscular states, (c) from subjective sensations due to the circulation, &c., or (d) from the ordinary cause of the action of external stimuli on the organs of sense.

(a) The state of the stomach, heart, &c., has long been recognized as important in the causation of dreams (see below, Classical Views). The common sensation of flying seems to be due in many cases to the disturbance of these organs setting up sensations resembling those felt in rapidly ascending or descending, as in a swing or a lift. Indigestion is a frequent cause of nightmare—the term given to oppressive and horrible dreams—and bodily discomfort is sometimes translated into the moral region, giving rise to the dream that a murder has been committed. (b) Dreams of flying, &c., have also been attributed to the condition of the muscles during sleep; W. Wundt remarks that the movements of the body, such as breathing, extensions of the limbs and so on, must give rise to dream fancies; the awkward position of the limbs may also excite images. (c) Especially important, probably, for the dreams of the early part of the night are the retinal conditions to which are due the illusions hypnagogiques of the preliminary drowsy stage; but probably Ladd goes too far in maintaining that entoptic stimuli, either intra- or extra-organic in origin, condition all dreams. Illusions hypnagogiques, termed popularly “faces in the dark,” of which Maury has given a full account, are the not uncommon sensations experienced, usually visual and seen with both open and closed eyes, in the interval between retiring to rest and actually falling asleep; they are comparable to the crystal-gazing visions of waking moments; though mainly visual they may also affect other senses. Besides the eye the ear may supply material for dreams, when the circulation of the blood suggests rushing waters or similar ideas. (d) It is a matter of common observation that the temperature of the surface of the body determines in many cases the character of the dreams, the real circumstances, as might be expected from the general character of the dream state, being exaggerated. In the same way the pressure of bed-clothes, obstruction of the supply of air, &c., may serve as the starting-point of dreams. The common dream of being unclothed may perhaps be due to this cause, the sensations associated with clothing being absent or so far modified as to be unrecognizable. In the same way the absence of foot-gear may account for some dreams of flying. It is possible to test the influence of external stimuli by direct experiment; Maury made a number of trials with the aid of an assistant.

Rapidity of Dreams.—It has often been asserted that we dream with extreme rapidity; but this statement is by no means borne out by experiment. In a trial recorded by J. Clavière the beginning of the dream was accurately fixed by the sounding of an alarm clock, which rang, then was silent for 22 seconds, and then began to ring continuously; the dream scene was in a theatre, and he found by actual trial that the time required in ordinary life for the performance of the scenes during the interval of silence was about the same as in ordinary life. Spontaneous dreams seem to show a different state of things; it must be remembered that (1) dreams are commonly a succession of images, the number of which cannot be legitimately compared with the number of extra-organic stimuli which would correspond to them in ordinary life; the real comparison is with mental images; and (2) the rapidity of association varies enormously in ordinary waking life. No proof, therefore, that some dreams are slow can show that this mentation in others is not extremely rapid. The most commonly quoted case is one of Maury’s; a bed-pole fell on his neck, and (so it is stated) he dreamt of the French Revolution, the scenes culminating in the fall of the guillotine on his neck; this has been held to show that (1) dreams are extremely rapid; and (2) we construct a dream story leading up to the external stimulus which is assumed to have originated the dream. But Maury’s dream was not recorded till many years after it had occurred; there is nothing to show that the dream, in this as in other similar cases, was not in progress when the bed-pole fell, which thus by mere coincidence would have intervened at the psychological moment; Maury’s memory on waking may have been to some extent hallucinatory. But there are records of waking states, not necessarily abnormal, in which time-perception is disturbed and brief incidents seem interminably long; on the other hand, it appears from the experiences of persons recovered from drowning that there is great rapidity of ideation before the extinction of consciousness; the same rapidity of thought has been observed in a fall from a bicycle.

Reason in Dreams.—Studies of dreams of normal individuals based on large collections of instances are singularly few in number; such as there are indicate great variations in the source of dream thoughts and images, in the coherence of the dream, and in the powers of memory. In ordinary life attention dominates the images presented; in dreams heterogeneous and disconnected elements are often combined; a resemblance need not even have been consciously recognized for the mind to combine two impressions in a dream; for example, an aching tooth may (according to the dream) be extracted, and found to resemble rocks on the sea-shore, which had not struck the waking mind as in any way like teeth. Incongruence and incoherence are not, however, a necessary characteristic of dreams, and individuals are found whose dream ideas and scenes show a power of reasoning and orderliness equal to that of a scene imagined or experienced in ordinary life. In some cases the reasoning power may attain a higher level than that of the ordinary conscious life. In a well-authenticated case Professor Hilprecht was able in a dream to solve a difficulty connected with two Babylonian inscriptions, which had not previously been recognized as complementary to each other; a point of peculiar interest is the dramatic form in which the information came to him—an old Babylonian priest appeared in his dream and gave him the clue to the problem (see also below, Personality).

Memory in Dreams.—Although prima facie the dream memory is fragmentary and far less complete than the waking memory, it is by no means uncommon to find a revival in sleep of early, apparently quite forgotten, experiences: more striking is the recollection in dreams of matters never supraliminally (see Subliminal Self) apperceived at all.

The relation between the memory in dreams and in the hypnotic trance is curious: suggestions given in the trance may be accepted and then forgotten or never remembered in ordinary life; this does not prevent them from reappearing occasionally in dreams; conversely dreams forgotten in ordinary life may be remembered in the hypnotic trance. These dream memories of other states of consciousness suggest that dreams are sometimes the product of a deeper stratum of the personality than comes into play in ordinary waking life. It must be remembered in this connexion that we judge of our dream consciousness by our waking recollections, not directly, and our recollection of our dreams is extraordinarily fragmentary; we do not know how far our dream memory really extends. Connected with memory of other states is the question of memory in dreams of previous dream states; occasionally a separate chain of memory, analogous to a secondary personality, seems to be formed. We may be also conscious that we have been dreaming, and subsequently, without intermediate waking, relate as a dream the dream previously experienced. In spite of the irrationality of dreams in general, it by no means follows that the earlier and later portions of a dream do not cohere; we may interpolate an episode and again take up the first motive, exactly as happens in real life. The strength of the dream memory is shown by the recurrence of images in dreams; a picture, the page of a book, or other image may be reproduced before our eyes several times in the course of a dream without the slightest alteration, although the waking consciousness would be quite incapable of such a feat of visualizing. In this connexion may be mentioned the phenomenon of redreaming; the same dream may recur either on the same or on different nights; this seems to be in many cases pathological or due to drugs, but may also occur under normal conditions.

Personality.—As a rule the personality of the dreamer is unchanged; but it also happens that the confusion of identity observed with regard to other objects embraces the dreamer himself; he imagines himself to be some one else; he is alternately actor and observer; he may see himself playing a part or may divest himself of his body and wander incorporeally. Ordinary dreams, however, do not go beyond a splitting of personality; we hold conversations, and are intensely surprised at the utterances of a dream figure, which, however, is merely an alter ego. As in the case of Hilprecht (see above) the information given by another part of the personality may not only appear but actually be novel.

Supernormal Dreams.—In addition to dreams in which there is a revival of memory or a rise into consciousness of facts previously only subliminally cognized, a certain number of dreams are on record in which telepathy (q.v.) seems to play a part; much of the evidence is, however, discounted by the possibility of hallucinatory memory. Another class of dreams (prodromic) is that in which the abnormal bodily states of the dreamer are brought to his knowledge in sleep, sometimes in a symbolical form; thus a dream of battle or sanguinary conflict may presage a haemorrhage. The increased power of suggestion which is the normal accompaniment of the hypnotic trance may make its appearance in dreams, and exercise either a curative influence or act capriciously in producing hysteria and the tropic changes known as “stigmata.” We may meet with various forms of hyperaesthesia in dreams; quite apart from the recovery of sight by those who have lost it wholly or in part (see below, Dreams of the Blind), we find that the powers of the senses may undergo an intensification, and, e.g., the power of appreciating music be enormously enhanced in persons usually indifferent to it. Mention must also be made of the experience of R. L. Stevenson, who tells in Across the Plains how by self-suggestion he was able to secure from his dreams the motives of some of his best romances.

Voluntary Action in Dreams.—Connected with dreams voluntarily influenced is the question of how far dreams once initiated are modifiable at the will of the dreamer. Some few observers, like F. W. H. Myers and Dr F. van Eeden, record that they can at longer or shorter intervals control their actions in their dreams, though usually to a less extent than their imagined actions in waking life. Dr van Eeden, for example, tells us that he has what he calls a “clear dream” once a month and is able to predetermine what he will do when he becomes aware that he is dreaming.

Dreams of Children.—Opinions differ widely as to the age at which children begin to dream; G. Compayré maintains that dreaming has been observed in the fourth month, but reflex action is always a possible explanation of the observed facts. S. de Sanctis found that in boys of eleven only one out of eight said that he dreamt seldom, as against four out of seven at the age of six; but we cannot exclude the possibility that dreams were frequent but forgotten. If correct, the observation suggests that dreams appear comparatively late. Individual cases of dreaming, or possibly of waking hallucination, are known as early as the age of two and a half years; according to de Sanctis dreams occur before the fifth year, but are seldom remembered; as a rule the conscious dream age begins with the fourth year; speech or movement, however, in earlier years, though they may be attributed to reflex action, are more probably due to dreams.

Dreams of the Old.—In normal individuals above the age of sixty-five de Sanctis found dreams were rare; atmospheric influences seem to be important elements in causing them; memory of them is weak; they are emotionally poor, and deal with long past scenes.

Dreams of Adults.—Any attempt to record or influence our dreams may be complicated by (a) direct suggestion, leading to the production of the phenomena for which we are looking, and (b) indirect suggestion leading to the more lively recollection of dreams in general and of certain dreams in particular. Consequently it cannot be assumed that the facts thus ascertained represent the normal conditions. According to F. Heerwagen’s statistics women sleep more lightly and dream more than men; the frequency of dreams is proportional to their vividness; women who dream sleep longer than those who do not; dreams tend to become less frequent with advancing age. The total number of remembered dreams varies considerably with different observers, some attaining an average of ten per night. The senses mainly active in dreams are, according to one set of experiments, vision in 60%, hearing in 5%, taste in 3%, and smell in 1.5%, where the dreamers had looked at coloured papers before falling asleep; when taste or smell had been stimulated, the visual dreams fell to about 50%, and the sense stimulated was active twice as often as it would otherwise be; dreams in which motion was a prominent feature were 10% of the former class, 14% and 18% of the two latter. Experiments by J. Mourly Vold show even more distinctly the influence of suggestion both as to the form, visual or otherwise, and the content (colours and forms of objects) of dreams. According to most observers dreams are most vivid and frequent between the ages of 20 and 25, but H. Maudsley puts the maximum between 30 and 35. De Sanctis got replies from 165 men and 55 women: the proportion between the sexes closely agrees with the results attained by Heerwagen and M. W. Calkins; 13% of men and 33% of women said they always dreamt, 27% and 45% often, 50% and 13% rarely, and the remainder (precisely the same percentage for men and women—9.09) either did not dream or did not remember that they dreamt. Nearly twice as many women as men had vivid dreams; in the matter of complication of the dream experiences the sexes are about equal; daily life supplies more material in the dreams of men; nearly twice as many women as men remember their dreams clearly, a fact which hangs together to some extent with the vividness of the dreams, though it by no means follows that a vivid dream is well remembered. There are great variations in the emotional character of dreams; some observers report twice as many unpleasant dreams as the reverse; in other cases the emotions seem to be absent; others again have none but pleasing dreams. Individual experience also varies very largely as to the time when most dreams are experienced; in some cases the great majority are subsequent to 6.30 A.M.; others find that quite half occur before 4.0 A.M.

Dreams of the Neuropathic, Insane, Idiots, &c.—Much attention has been given to the dreams of hysterical subjects. It appears that their dreams are specially liable to exercise an influence over their waking life, perhaps because they do not distinguish them, any more than their waking hallucinations, from reality. P. Janet maintains that the cause of hysteria may be sought in a dream. The dreams of the hysterical have a tendency to recur. Epileptic subjects dream less than the hysterical, and their dreams are seldom of a terrifying nature; certain dreams seem to take the place of an epileptic attack. Dreaming seems to be rare in idiots. De Sanctis divides paranoiacs into three classes: (a) those with systematized delusions, (b) those with frequent hallucinations, and (c) degenerates;—the dreams of the first class resemble their delusions; the second class is distinguished by the complexity of its dreams; the third by their vividness, by their delusions of megalomania, and by their influence on daily life. Alcoholic subjects have vivid and terrifying dreams, characterized by the frequent appearance of animals in them, and delirium tremens may originate during sleep.

Dreams of the Blind, Deaf, &c.—As regards visual dreams the blind fall into three classes—(1) those who are blind from birth or become blind before the age of five; (2) those who become blind at the “critical age” from five to seven; (3) those who become blind after the age of seven. The dreams of the first class are non-visual; but in the dreams of Helen Keller there are traces of a visual content; the second class sometimes has visual dreams; the third class does not differ from normal persons, though visual dreams may fade away after many years of blindness. In the case of the partially blind the clearness of vision in a dream exceeds that of normal life when the partial loss of sight occurred in the sixth or later years. The education of Helen Keller is interesting from another point of view; after losing the senses of sight and hearing in infancy she began her education at seven years and was able to articulate at eleven; it is recorded that she “talked” in her dreams soon after. This accords with the experience of normal individuals who acquire a foreign language. Her extraordinary memory enables her to recall faintly some traces of the sunlit period of her life, but they hardly affect her dreams, so far as can be judged. The dreams of the blind, according to the records of F. Hitschmann, present some peculiarities; animals as well as man speak; toothache and bodily pains are perceived as such; impersonal dreaming, taking the form of a drama or reading aloud, is found; and he had a strong tendency to reproduce or create verse.

Dreams of Animals.—We are naturally reduced to inference in dealing with animals as with very young children; but various observations seem to show that dreams are common in older dogs, especially after hunting expeditions; in young dogs sleep seems to be quieter; dogs accustomed to the chase seem to dream more than other kinds.

Dreams among the Non-European Peoples.—In the lower stages of culture the dream is regarded as no less real and its personages as no less objective than those of the ordinary waking life; this is due in the main to the habit of mind of such peoples (see Animism), but possibly in some measure also to the occurrence of veridical dreams (see Telepathy). In either case the savage explanation is animistic, and animism is commonly assumed to have been developed very largely as a result of theorising dreams. Two explanations of a dream are found among the lower races: (1) that the soul of the dreamer goes out, and visits his friends, living or dead, his old haunts or unfamiliar scenes and so on; or (2) that the souls of the dead and others come to visit him, either of their own motion or at divine command. In either of the latter cases or at a higher stage of culture when the dream is regarded as god-sent, though no longer explained in terms of animism, it is often regarded as oracular (see Oracle), the explanation being sometimes symbolical, sometimes simple.

There are two classes of dreams which have a special importance in the lower cultures: (1) the dream or vision of the initiation fast; and (2) the dream caused by the process known as incubation, which is often analogous to the initiation fast. In many parts of North America the individual Indian acquires a tutelary spirit, known as manito or nagual, by his initiation dream or vision; the idea being perhaps that the spirit by the act of appearing shows its subjection to the will of the man. Similarly, the magician acquires his familiar in North America, Australia and elsewhere by dreaming of an animal. Incubation consists in retiring to sleep in a temple, sometimes on the top of a mountain or other unusual spot, in order to obtain a revelation through a dream. Fasting, continence and other observances are frequently prescribed as preliminaries. Certain classes of dreams have, especially in the middle ages, been attributed to the influence of evil spirits (see Demonology).

Classical and Medieval Views of Dreams.—Side by side with the prevalent animistic view of dreams we find in antiquity and among the semi-civilized attempts at philosophical or physiological explanations of dreams. Democritus, from whom the Epicureans derived their theory, held the cause of them to be the simulacra or phantasms of corporeal objects which are constantly floating about the atmosphere and attack the soul in sleep—a view hardly distinguishable from animism. Aristotle, however, refers them to the impressions left by objects seen with the eyes of the body; he further remarks on the exaggeration of slight stimuli when they are incorporated into a dream; a small sound becomes a noise like thunder. Plato, too, connects dreaming with the normal waking operations of the mind; Pliny, on the other hand, admits this only for dreams which take place after meals, the remainder being supernatural. Cicero, however, takes the view that they are simply natural occurrences no more and no less than the mental operations and sensations of the waking state. The pathological side of dreams attracted the notice of physicians. Hippocrates was disposed to admit that some dreams might be divine, but held that others were premonitory of diseased states of the body. Galen took the same view in some of his speculations.

Symbolical interpretations are combined with pathological no less than animistic interpretations of dreams; they are also extremely common among the lower classes in Europe at the present day, but in this case no consistent explanation of their importance for the divination of future events is usually discoverable. Among the Greeks Plato in the Timaeus (ch. xlvi., xlvii.) explains dreams as prophetic visions received by the lower appetitive soul through the liver; their interpretation requires intelligence. The Stoics seem to have held that dreams may be a divine revelation and more than one volume on the interpretation of dreams has come down to us, the most important being perhaps the Όνειροκριτικά of Daldianus Artemidorus. We find parallels to this in a Mussulman work by Gabdorrachaman, translated by Pierre Vattier under the name of Onirocrite mussulman, and in the numerous books on the interpretation of dreams which circulate at the present day. In Siam dream books are found (Intern. Archiv für Anthr. viii. 150); one of the functions of the Australian medicine man is to decide how a dream is to be interpreted.

Modern Views.—The doctrine of Descartes that existence depended upon thought naturally led his followers to maintain that the mind is always thinking and consequently that dreaming is continuous. Locke replied to this that men are not always conscious of dreaming, and it is hard to be conceived that the soul of the sleeping man should this moment be thinking, while the soul of the waking man cannot recollect in the next moment a jot of all those thoughts. That we always dream was maintained by Leibnitz, Kant, Sir W. Hamilton and others; the latter refutes the argument of Locke by the just observation that the somnambulist has certainly been conscious, but fails to recall the fact when he returns to the normal state.

It has been commonly held by metaphysicians that the nature of dreams is explained by the suspension of volition during sleep; Dugald Stewart asserts that it is not wholly dormant but loses its hold on the faculties, and he thus accounts for the incoherence of dreams and the apparent reality of dream images.

Cudworth, from the orderly sequence of dream combinations and their novelty, argues that the state arises, not from any “fortuitous dancings of the spirits,” but from the “phantastical power of the soul.” According to K. A. Scherner, dreaming is a decentralization of the movement of life; the ego becomes purely receptive and is merely the point around which the peripheral life plays in perfect freedom. Hobbes held that dreams all proceed from the agitation of the inward parts of a man’s body, which, owing to their connexion with the brain, serve to keep the latter in motion. For Schopenhauer the cause of dreams is the stimulation of the brain by the internal regions of the organism through the sympathetic nervous system. These impressions the mind afterwards works up into quasi-realities by means of its forms of space, time, causality, &c.

Bibliography.—For full lists of books and articles see J. M. Baldwin’s Dictionary of Philosophy, bibliography volume (1906), and S. de Sanctis, I Sogni, also translated in German with additions as Die Träume. Important works are—Binz, Über den Traum, Giessler Aus den Tiefen des Traumlebens, Maury, Le Sommeil et les rêves, Radestock, Schlaf und Traum, Tessié, Les Rêves, Spitta, Schlaf und Traumzustände. For super-normal dreams see F. W. H. Myers, Human Personality, vol. i., and Proc. S.P.R. viii. 362. For voluntary dreams see Proc. S.P.R. iv. 241, xvii. 112. On prophetic dreams see Monist, xi. 161, Bull. Soc. Anth. (Paris, 1901), 196, (1902), 228, Rev. de synthèse historique (1901), 151, &c. On incubation see Deubner, De incubatione, Maury, La Magie. On the dreams of American Indians see Handbook of American Indians (Washington, 1907), s.v. “Dreams” and “Manito.” On the interpretation of dreams see Freud, Die Traumdeutung. Other works are F. Greenwood, Imagination in Dreams, Hutchinson, Dreams and their Meanings.  (N. W. T.)