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
