There are subsidiary questions such as "do animals have dreams?" which relate to the general issue. Even more importantly, as I think Freud recognized, dreams probably connect with human creativity and writing--if not directly--then in terms of shared cognitive processes. Where do "ideas" come from, anyway?
"..in sleep we continually seem to feel or imagine innumerable things which have no existence." R. Descartes (164x)
"While dreaming, we believe we are executing a movement and we then continue dreamng that what actually happens is a natural consequence of the movement.. H. von Helmholtz (1863/1968)"
"It is from these dream-thoughts and not from a dream's manifest content that we disentangle its meaning. We are thus presented with a new task...of investigating the relations between the manifest content of dreams and the latent dream thoughts, and of tracing out the processes by which the latter have been changed into the former. The dream-thoughts and the dream-content are presented to us like two versions of the same subject-matter in two different languages....the dream content seems like a transcript of the dream-thoughts into another mode of expression, whose characters and syntactic laws it is our business to discover by comparing the original and the translation....The dream content...is expressed as it were in a pictographic script, the characters of which have to be transposed individually into the language of the dream-thoughts..If we attempted to read these..according to their pictorial value instead of according to their symbolic relation, we should clearly be led into error." (ch. VI, pp.311-312, Freud, 1900/1965)
Figure 1. Sketch of Freud's dream scheme (my interpretation)
"All subjective experience, including dreaming, tends to be organized by the linguistic faculty of our brain-minds as a narrative scenerio. (Hobson, 1988, p.203)"
Hobson (1988, p.226) reports that sleep lab subjects' estimations of dream duration correlated positively with time in REM sleep prior to arousal. This really doesn't address the actual symbolic time of a dream. [IT SHOULD BE FAIRLY EASY TO GET SOME ESTIMATES ON THIS.]
Winson (1988) offers this "explanation": In evolution the limbic-frontal cortical system...operated only on action and remains the same in man. "Thus, abstract concepts arising with language...can only be integrated into our unconscious brain mechanism by translation into visual scenes and actions..218" Hobson (1988) notes that taste and smell seem underrepresented and pain reports are quite rare.
Winson gives an example "Lets say that the unconscious statement to be made was....and further that this statement had to be expressed via sequence of events because the constraints placed on the brain mechanism corresponding to the unconscious as a result of its phylogenetic origin required it. Associative paths would be search...this selection would be made.....In any case, the unconscious associational network utilized these symbols for a statement....free association was a truly remarkable discovery of Freud's..it allows one to follow the associational paths of the search.....in terms of my theory ...in the search for representability in the manifest dream, the emotional content may at times be sacrificed.
Erdelyi (1985), similarly, says the primitive character of dream symbolism reflects the fact that dreams are generally experienced not in language of abstractions but in concrete sensory-motor images, in pictures, sounds, smellls, bodily sensations, and actions...a consequence of disinhibition in dreasm of primiitve primary-process functioning, a notable featuer of which is imagistic representation. p.153."
Verbal imagery is more likely in non-REM sleep (Foulkes, 1978), though visual imagery seems to always predominate.
REM("Rapid Eye Movement") activity is consistent with a causal and visual dream report. "When scored for vividness, emotionality, and imagined physical activity, these psychological measures also correlated positively with the quantitative intensity of the eye movement in the REM sleep just prior to awakening. Hobson, 1988, p.142"
"Dreams are intensely visual and visual neurons fire intensely during REM sleep. H, p.171"
Hobson, p.239 reports color imagery is common and attributes lack of color report to poor recall.
"Dreaming is as fascinating for its overrepresentation of visual, as it is for its underrepresentationof visceral, perceptions...parallels in the reciprocal physiology of REM sleep. Hobson, p.246"
MOST IMPORTANT, perhaps, is Hobson's questioning of the "modern sleep science" tradition to represent dreams as verbal reports. In comment on his "Engine Man", he says "I know of no previous attempot to analysize their direct visual representation in drawings....many intensive students of dream consciousness have naturally resorted to drawing in addition to their narrative accounts. p.240" H notes artists like William Blake and S. Dali documented the "ulnique visula nature of dream consciousness."
There is some controversy about possible differences between dreams obtained from laboratories and those reported under natural "home" sleep conditions--which some claim are richer and more fantastic than the lab dreams. However several systematic comparisons do not support any difference. (Foulkes, 1978, p.354.)
Hobson and others remark on the strange, uncritical acceptance of the most bizzare, impossible dream situations. "Dreams put these bizzare elements together with a convincing reality, a pictorical clarity, sometimes even an artistic talent that are difficult for most of us to achieve in the waking state.....This imaginative quality of dreaming fascinated the European artists who...called themselves surrealists....during dreaming many integrations of disparate cognitive elements are tried, a process akin to the hypothesis -testing process of science...only ot be seen in the light of day as illusory, fanciful, and useless. p.18"
Hobson suggests hearing occurs in 65% of lab REM reports (p.243) and more often qualified by uncertainty than visual experiences.
[this could explain my (JL) own very fragmented recall of dreams--generally without narrative 'syntax']
Freud goes on to say that it is "highly probable that the psychical function which carries out what we have described as the secondary revision of the content of dreams is to be identified with the activity of our waking thought. Our waking (preconscious) thinking behaves towards any perceptual material with which it meets in just the same way in which the function we are considering behaves towards the contents of dreams. It is the nature of our waking thought to establish order in material of that kind, to set up relations in it and to make it conform to our expectations of an intelligible whole."
[NOTE HOW THIS COULD BE INTERPRETED AS MAKING THE STRUCTURE OF LANGUAGE OR MENTALESE RESPONSIBLE FOR THE NARRATIVE CONNECTEDNESS OF DREAMS] Do animals have this ability in their "preconscious" even if they have the much the same unconscious dream-thoughts?
"There is no doubt then, that it is our normal thinking that is the psychical agency which approaches the content of dreams with a demand that it must be intelligible, which subjects it to a first interpretation and which consequently produces a complete misunderstanding of it. " [p.538 , Freud, ch.IV] [OF COURSE WE DON'T HAVE TO ACCEPT THE PRESUPPOSITION THAT THERE WAS AN "INTENDED" INTERPRETATION IN THE FIRST PLACE--DO WE? JL]
Laboratory studies indicate young adults report dream over 80% of the time when awakened during REM sleep and as little of 20% of the time when awakened in non-REM periods.
Various regions of the brain are active in REM. Using PET scans areas dealing with "language processing, cognition, reflection, and sensory functions" (Gottschalk et al, 1991). SO dreams are LOCALIZED!!!! (joke)
Major movements of the body are inhibited during REM. Motor cells governing muscles are actively inhibited during each REM period. Nightmares and sleepwalking are not typically associated with REM sleep.
"The brain stem is the nightly battleground of warring neuronal factions, and REM sleep and dreaming are the result of temporary domination of one neuronal population over another. Hobson, 1988, p.183) It appears that the "battle" is between reciprocal "REM-on" and "REM-off" inhibitory neuronal populations. [This is probably the general plan of brain function; for example also exhibited in split-brain patient conflicts.]
A number clinical studies suggest that REM sleep can be chemically induced. Gillin et al (198x) found that subjects awakened from artificially induced REM sleep, report "mental activity with all the formal characteristics of dreaming. Hobson, 1988, p.201)
"..the size of the brain seems to be the critical spatial variable in determining the duration of sleep-cycle periods....it is the width of the brain stem that correlates best with sleep-cycle length...bigger heads have less frequent but longer dreams. Hobson, p.191."
Studies of REM-sleep deprivation effects seem contradictory. e.g. Foulkes, p.95.
The amount of sleep and proportion of REM sleep varies by species-predators like humans and cats having the most of each.
The earliest mammals, egg layers, such as the platypus and echinida, in particular, have no REM sleep. [Winson, p.54]
Walker (1983) reports that some birds and maybe some diurnal reptiles have some dream-correlate states--REM for birds, loss of attention and eye-drooping in lizards.
Freud and others emphasize that "infantile" material as well as recent experiences are the source of dream material.
"By age two the child is becoming aware of his or her own existence, and I postulate that impressions are rapidly being formed and integrated into the unconscious during off-line processing in REM sleep. This continues at a decelerating rate until the end of the critical period, an indefinite time perhaps as late as adolescence.. REM processing continues throughout life, but it is the earlier impressions, those acquired during the critical period, that are the basis for the interpretation of many later events. Above and beyond this there is normal learning, which grows throughout life. W."p220.
Not surprisingly, Piaget (1951/1966) has some useful ideas on this topic, as well as a critique of Freud and Jung.
However it appears that everyone agrees that dream meanings are somehow "associated" with recent --"daily residues"---and perhaps early childhood events. This is the one aspect of Freud's early work that continues to be supported--although the application of the idea can be so unsystematic that imaginative interpreters can find almost anything in a dream.
"Free Association" thus was a method of interpretation developed by Freud that is still useful, probably because dream contents are in part --if not entirely--formed by associative processes. [Foulkes (1978) developed an interesting "linguistic" method of scoring dream associations. All these methods are forms of "content analysis."]
Not many outside of the Freudian tradition--including me--want to accept the "censorship" and related mechanisms as self-evident.
Hobson (1988) suggests "I am not asserting that dreams are either meaningless or unworthy of clinical attention. On the contrary,...the meaninging of dreams is...transparent rather than concealed, since fundamentally incoherent cognitive elements are syntheszied in a personally meaningful way...p.258"
(THAT IS CONSISTENT WITH finding a correlation between rate of second language learning and increased REM sleep, i.e. better scores > more REM.)
This would be particularly important during early development when pruning of circuits is occuring. REM may serve to activate relevant circuits and not others--a mechanism of pruning neurons and synapses WITHOUT the necessity of the corresponding motor activities which are suppressed. (Recall the facial expressions Hobson (1988) discusses a similar, less sophisticated idea "REM sleep could provide the brain with a higly organized program of internal action .p.293"
Walker (1983) suggests that the simplest idea is that REM states began as a device for ensuring a modicum of metabolic activity in warm-blooded animals undergoing energy-conserving quiescence. p.234 (This sounds analogous the truckers keeping their diesels running on cold nights!)
Hobson (1988), similar to Winson (1988) also emphasizes brain activity: "the form of dreams is related to the form of brain activity in sleep; and that the brain is first turned on during sleep and then generates and integrates (syntheszies) its own sensory and motor information...(these) are both the driving force and the directional vector for the dream plot, which is syntheszied in light of an individual's past experiences, attitudes, and expectations. p.15"
Hobson discusses a brain maintenance hypothesis; REM sleep "allows us to rev our cerebral motor and actively to test all our circuits in a reliably patterned way."
Complementary to the idea of establishing long term "traces" is elimination of needless trivial information that might be clogging up the brain's "information highways."
Some have proposed sleep simply keeps us off the street during dangerous times!
"The wildness of our dreams seems to be of singular use to us, by interrupting and breaking the course of our associations, (David Hartley, in Observations on Man (p. 389). [See Crovitz' Galton's Walk! on this issue.]
Numerous anecdotes on discoveries appearing in sleep or upon waking are well known. Similarly the relation between dreaming and art is often remarked upon.
Similarly the artistic abilities of children and cave paintings of early hominids may relate to the visual, creative nature of dream states.
[Freud's idea at least appears to require "dreams" as part of the causal story--unlike those accounts in terms of REM sleep or just sleep. Hobson, for example, in his discussion of dream functions includes a variety of possibilities, e.g. rest for neurons and neurotransmitter resupply, that seem NOT to require any of the epiphenomenal features we call dreams. His REM "maintenance" hypothesis on the other hand could involve dreaming since the linguistic and/or cognitive processes in interpretation would be among those exercised.]
Erdelyi (1985) says "One can informally glimpse the operation of secondary revision by comparing dream recalls recorded immediately upon awakening to those recorded after the lapse of time. The latter loose some of the wild, fantastic, paraverbal twistings of the former becoming more mundanely realistic versions of them." 156."
Condensation allows the story told by the dream--manifest content--to be much more "compressed" than the original material (latent content?) Examples include composite characters and contracted words. A manifest element may lead to several elements in the latent content.
Displacement occurs when an insignificant latent element is "traced" to emotionally powerful elements of the latent content that evaded the censor.
Representability is a process where an abstract idea or word is portrayed in a dream by visual imagery
Symbolism is another process whereby one element in latent content "dream thought" is represented by another form or image.
In the dream processes, symbolism was traced to "unconscious biogenetic knowledge, similar to having an inborn understandng of Sanskrit...he agreed with philologist Hans Sperber (1912) who maintained that words and language were originally dervied from sexual needs--for example to summon the sexual partner. Gradually sexual words were applied to the working activities of primal man and so took on double meanings.[cited in Sulloway, 1979, p..338] Freud has both ontogenetic symbols and phylogenetic symbols.
[Dreams] are psychical phenomena...--fulfillment of wishes;...they are constructed by a highly complicated activity of the mind." ch.3. SF relates how eating salty foods guarantees a dream in which he is swallowing great gulps of water. "Then I wake up and have to have a real drink." This is a dream of convenience. Dreaming has taken the place of action."
"I suggest then that dreams are the statements, wishes, hopes, and fears of the unconscious personality. Their..content, that is what captures the interest of our unconscious personality--is to some extent dependent on life's events.
I have now completed my theory of the unconscious. In lower mammals it was the complete neural system needed to learn from experience, build up a plan for purposive behavior, and survive..in the course of evolution a new neural mechanism was added--that responsible for consciousness of oneself and the world "
During REM, otherwise inhibited cells become active; they "run free of restraint from both external stimuli and internal inhibition. p.206" This inhibition is manifest at physiological levels through depolarization, blockage, competition, and "the facile incorporation of [signals] into the internally generated information stream of dreaming." At the same time, motor output is inhibited.
Three processes, thus, enable REM sleep dreaming: (1) activation, (2) exclusion of external sense data, and (3) motor output blockage.
Hobson, p.229 notes the difference between "dream form" and "dream content." The former is a physiological universal while the later depends on individual experiences.
"The wildness of our dreams seems to be of singular use to us, by interrupting and breaking the course of our associations, (David Hartley, 1807 in Observations on Man (1801)
Freud, S. (1900/1938). The interpretation of dreams. In A. A. Brill (Ed.), The basic writings of Sigmund Freud (pp. 181-552). New York: Random House.
Freud, S. (1930/1965). The interpretation of dreams (Eighth ed.). New York: Avon Books. (Most of the quotes come from this version, a translation of the Eighth German edition by James Strachey.)
Foulkes, D. (1978). A grammar of dreams . New York: Basic Books.
Hartley, D. (1749/1966). Observations on Man, His frame, his deity, and his expectations . Gainesville, FL: Scholars Facsimile Reprints.
Hobson, J. A. (1988). The dreaming brain . New York: Basic Books.
Jones, E. (1961/1963). The life and work of Sigmund Freud (abridged ed.). Garden City: Doubleday and Company.
Piaget, J. (1951/1966) Play, dreams, and imitation in childhood. New York: Norton & Co.
Roffwarg, H., Muzio, J. N., and Dement, W. C. (1966) Ontogenetic development of the human sleep-dream cycle. Science, 152, 604-619.
Sulloway, F. J. (1979). Freud, biologist of the mind . New York: Basic Books, Inc.
Winson, J. (1985). Brain and psyche . Garden City, NY: Anchor Press/Doubleday. [The author is a neuroscientist doing research on memory and the hypothalamus; his book tries to reinterpret Freud's dream theory on the basis of recent research into the nervous system. He has a decent summary of Freud, too.]
Walker, S. (1983). Animal thought . London: Routledge & Kegan Paul.