As a last factor favouring the forgetting of dreams, we may mention the fact that most people generally take little interest in their dreams. One who investigates dreams for a time, and takes a special interest in them, usually dreams more during that time than at any other; that is, he remembers his dreams more easily and more frequently.
Two other reasons for the forgetting of dreams added by Bonatelli (given by Benini3) to those of Strümpell have already been included in the latter; namely, (1) that the change of the general feeling between the sleeping and waking states is unfavourable to the mutual reproductions, and (2) that the different arrangement of the presentation material in the dream makes the dream untranslatable, so to speak, for the waking consciousness.
It is the more remarkable, as Strümpell observes, that, in spite of all these reasons for forgetting the dream, so many dreams are retained in memory. The continued efforts of the authors to formulate laws for the remembering of dreams amounts to an admission that here too there is something puzzling and unsolved. Certain peculiarities relating to the memory of dreams have been particularly noticed of late, e.g., that a dream which is considered forgotten in the morning may be recalled in the course of the day through a perception which accidentally touches the forgotten content of the dream (Radestock,54 Tissié68). The entire memory of the dream is open to an objection calculated to depreciate its value very markedly in critical eyes. One may doubt whether our memory, which omits so much from the dream, does not falsify what it retained.
Such doubts relating to the exactness of the reproduction of the dream are expressed by Strümpell when he says: "It therefore easily happens that the active consciousness involuntarily inserts much in recollection of the dream; one imagines one has dreamt all sorts of things which the actual dream did not contain."
Jessen36 (p. 547) expresses himself very decidedly: "Moreover we must not lose sight of the fact, hitherto little heeded, that in the investigation and interpretation of orderly and logical dreams we almost always play with the truth when we recall a dream to memory. Unconsciously and unwittingly we fill up the gaps and supplement the dream pictures. Rarely, and perhaps never, has a connected dream been as connected as it appears to us in memory. Even the most truth-loving person can hardly relate a dream without exaggerating and embellishing it. The tendency of the human mind to conceive everything in connection is so great that it unwittingly supplies the deficiencies of connection if the dream is recalled somewhat disconnectedly."
The observations of V. Eggers,20 though surely independently conceived, sound almost like a translation of Jessen's words: "...L'observation des rêves a ses difficultés spéciales et le seul moyen d'eviter toute erreur en pareille matière est de confier au papier sans le moindre retard ce que l'on vient d'éprouver et de remarquer; sinon, l'oubli vient vite ou total ou partiel; l'oubli total est sans gravité; mais l'oubli partiel est perfide; car si l'on se met ensuite à raconter ce que l'on n'a pas oublié, on est exposé à compléter par imagination les fragments incohérents et disjoints fourni par la memoire...; on devient artiste à son insu, et le récit, periodiquement répété s'impose à la créance de son auteur, qui, de bonne foi, le présente comme un fait authentique, dûment établi selon les bonnes méthodes..."
Similarly Spitta,64 who seems to think that it is only in our attempt to reproduce the dream that we put in order the loosely associated dream elements: "To make connection out of disconnection, that is, to add the process of logical connection which is absent in the dream."
As we do not at present possess any other objective control for the reliability of our memory, and as indeed such a control is impossible in examining the dream which is our own experience, and for which our memory is the only source, it is a question what value we may attach to our recollections of dreams.
(e) The Psychological Peculiarities of Dreams.—In the scientific investigation of the dream we start with the assumption that the dream is an occurrence of our own psychic activity; nevertheless the finished dream appears to us as something strange, the authorship of which we are so little forced to recognise that we can just as easily say "a dream appeared to me," as "I have dreamt." Whence this "psychic strangeness" of the dream? According to our discussion of the sources of dreams we may suppose that it does not depend on the material reaching the dream content; because this is for the most part common to the dream life and waking life. One may ask whether in the dream it is not changes in the psychic processes which call forth this impression, and may so put to test a psychological characteristic of the dream.
No one has more strongly emphasized the essential difference between dream and waking life, and utilised this difference for more far-reaching conclusions, than G. Th. Fechner25 in some observations in his Elements of Psychophysic (p. 520, part 11). He believes that "neither the simple depression of conscious psychic life under the main threshold," nor the distraction of attention from the influences of the outer world, suffices to explain the peculiarities of the dream life as compared with the waking life. He rather believes that the scene of dreams is laid elsewhere than in the waking presentation life. "If the scene of the psychophysical activity were the same during the sleeping and the waking states, the dream, in my opinion, could only be a continuation of the waking ideation maintaining itself at a lower degree of intensity, and must moreover share with the latter its material and form. But the state of affairs is quite different."
What Fechner really meant has never been made clear, nor has anybody else, to my knowledge, followed further the road, the clue to which he indicated in this remark. An anatomical interpretation in the sense of physiological brain localisations, or even in reference to histological sections of the cerebral cortex, will surely have to be excluded. The thought may, however, prove ingenious and fruitful if it can be referred to a psychic apparatus which is constructed out of many instances placed one behind another.
Other authors have been content to render prominent one or another of the tangible psychological peculiarities of the dream life, and perhaps to take these as a starting point for more far-reaching attempts at explanation.
It has been justly remarked that one of the main peculiarities of the dream life appears even in the state of falling asleep, and is to be designated as the phenomenon inducing sleep. According to Schleiermacher61 (p. 351), the characteristic part of the waking state is the fact that the psychic activity occurs in ideas rather than in pictures. But the dream thinks in pictures, and one may observe that with the approach of sleep the voluntary activities become difficult in the same measure as the involuntary appear, the latter belonging wholly to the class of pictures. The inability for such presentation work as we perceive to be intentionally desired, and the appearance of pictures which is regularly connected with this distraction, these are two qualities which are constant in the dream, and which in its psychological analysis we must recognise as essential characters of the dream life. Concerning the pictures—the hypnogogic hallucinations—we have discovered that even in their content they are identical with the dream pictures.
The dream therefore thinks preponderately, but not exclusively, in visual pictures. It also makes use of auditory pictures, and to a lesser extent of the impressions of the other senses. Much is also simply thought or imagined (probably represented by remnants of word presentations), just as in the waking state. But still what is characteristic for the dream is only those elements of the content which act like pictures, i.e. which resemble more the perceptions than the memory presentations. Disregarding all the discussions concerning the nature of hallucinations, familiar to every psychiatrist, we can say, with all well-versed authors, that the dream hallucinates, that is, replaces thoughts through hallucinations. In this respect there is no difference between visual and acoustic presentations ; it has been noticed that the memory of a succession of sounds with which one falls asleep becomes transformed while sinking into sleep into an hallucination of the same melody, so as to make room again on awakening, which may repeatedly alternate with falling into a slumber,