The Case Against the Problem-Solving Theory of Dreaming
G. William Domhoff
NOTE: This is an unpublished paper. If you use this article in research, please use the following citation:
Domhoff, G. W. (2003). The Case Against the Problem-Solving Theory of Dreaming. Retrieved from the World Wide Web: http://dreamresearch.net/Library/domhoff_2004b.html
There are innumerable theories of dream function (Dallett, 1973). All of them are highly speculative and difficult to refute in a definitive way, and they therefore linger despite a lack of evidence for any of them. This situation also provides a fertile terrain for new and unlikely theories based on analogies drawn from each development or discovery in other areas of research. This search for a function seems necessary and sensible to most people, but it rests on the false "adaptationist" assumption that "all the things that have form have function" (Thompson, 2000, p. 1014). In fact, many structures and processes persist even though they have no function, and dreaming may be one of them (Flanagan, 1995; Flanagan, 2000a).
Aside from Freud's guardian-of-sleep theory and Jung's compensatory theory, which we have refuted elsewhere, the most prominent theory of dream function is that dreams provide solutions to current problems, especially emotional problems (Barrett, 1993; Greenberg, Katz, Schwartz, & Pearlman, 1992; Greenberg & Pearlman, 1993). In one variant, Fiss (1993) suggests that dreams are especially good at registering subtle internal and external signals that often go undetected in waking life, making them potentially useful for picking up early signs of physical illness.
There are many empirical findings about dreams that do not fit well with any problem-solving theory. To begin with, the idea that dreams have a purpose originated at a time when it was thought that people rarely dream. In that context, it was plausible to believe that the occasional recalled dream could be a reaction to a specific event or emotional problem. But if most adults dream at least four to six times per night, then most people are recalling less than 1 percent of their dreams. Even the best dream recallers only remember a few percent of their dreams. This lack of recall suggests that dreams in general are not an evolutionary adaptation to provide information or insight to people when they are awake.
In addition, only about half of recalled dreams seem to have even the slightest connection to the events of the previous day (Botman & Crovitz, 1989; Harlow & Roll, 1992; Hartmann, 1968; Marquardt, Bonato, & Hoffmann, 1996; Nielsen & Powell, 1992). Kramer (2000) claims on the basis of one small clinical study that the concerns of the day are incorporated into dreams, but more recent and larger studies, in which judges try to match expressed daytime concerns with dream reports from laboratory awakenings, have proven unsuccessful (Roussy, 2000; Roussy et al., 2000a). It is unlikely that dreams very often deal with immediately relevant issues, although they do dramatize ongoing emotional preoccupations in many instances.
If dreams contain important information for consideration in waking consciousness, then it might be predicted that those who do not remember or pay attention to their dreams might suffer some disadvantages. But those who rarely recall dreams do not differ in terms of personality or mental difficulties when compared with those who recall dreams regularly (Antrobus, 1993; Blagrove & Akehurst, 2000; Cohen, 1979; Goodenough, 1991; Tonay, 1993). Generally speaking, it is very difficult to distinguish "recallers" from "non-recallers" with either personality or cognitive tests. If incorporating and dealing with the content of dreams mattered for psychological well being, a different set of findings might be expected. In fact, contrary to any theory that emphasizes the problem-solving nature of dreams, dream recall is often more disturbing than it is helpful, as shown most dramatically with people who suffer from post-traumatic stress disorder. Many people also suffer from their recurrent dreams (Zadra, 1996; Zadra & Donderi, 2000a).
It is also unlikely that dreams contain new information on physical illnesses. The few dream studies cited by Fiss (1993) are clinical studies with very small samples. They claim to find differences in themes concerning hostility or separation, but no direct indications of illness, as Fiss acknowledges. His signal detection theory of dream function therefore rests on an extrapolation from the literature on subliminal stimulation. But most research psychologists remain highly doubtful that any strong effect for subliminal stimulation has been demonstrated, or that what has been demonstrated relates to psychodynamic claims about the unconscious (Fudin, 1999; Greenwald, 1992; Greenwald, Draine, & Abrams, 1996).
Faced with the findings on the rarity of recall and of dream content related to current events, some proponents of problem-solving theories now claim that only important and impactful emotional dreams have a problem-solving function. There are two important distinctions that have to be made in analyzing this claim. First, it is one thing for a dream to "reflect" a problem; it is quite another for it to offer a "solution." Second, a distinction has to be made between solutions that are present within a dream, on the one hand, and waking realizations that are based upon thinking about the dream on the other. Realizations in the waking state are a much more plausible alternative because there is evidence that conscious attention is needed for problem solving (Blagrove, 1992; Blagrove, 1996; Foulkes, 1985). Viewed in this way, human beings have developed "uses" for dreams in the course of history, including personal development (Fiss, 1983; Fiss, 1991; Hunt, 1989). But cultural uses are not the same as evolved psychological functions.
Cartwright's work with people going through a divorce is sometimes interpreted as showing that dreams contain solutions, because those who dream of the former spouse "have a better outcome" (1996, p. 185). However, dreaming about a former spouse does not necessarily mean that the dreams contain any solutions to problems arising from the divorce. Instead, it more likely simply "reflects" a concern with the issue. Moreover, there are also severe methodological limits to her study. Her claims would have to be replicated in new and larger studies before they could be taken seriously as a basis for theorizing. As Cartwright herself concludes: "The study is suggestive. There are many ways in which it could be faulted. There was only one night of dream collection, and some who did not dream of the spouse that night might well be experiencing a great deal of incorporation of the problem of this relationship on other nights. Also there was a long gap between that one night of dreaming and the follow-up interview, during which many new reality factors would have intervened" (Cartwright, 1996, p. 185).
The difficulties of demonstrating problem-solving in dreams are shown in a study of 76 college students between the ages of 19 and 24. In order to increase relevance and motivation for the task, they were allowed to choose the problem they hoped to resolve (Barrett, 1993). Participants were asked to write out the problem, think about it, and keep a dream journal for a week or until they recalled a dream that seemed to solve the problem. Both the participants and two independent judges rated whether the dreams were (1) on the topic and (2) contained a satisfactory solution. Only half the participants recalled a dream they felt related to the problem. These dreams usually concerned relationship dilemmas or educational/vocational decisions. There were but two instances where both the dreamer and the two judges agreed that the dreams contained the problem and offered a plausible solution. Both dreams seem to reflect the dreamers' concerns, but do not contain "solutions." They dramatize problems, as many dreams do. In the first instance the dreamer is "having major problems with my menstrual cycle and my doctor can't figure out what is wrong."
She reports the following dream, with a comment about it at the end: "Dream: My doctor told me I was having a reaction from being on a diet and exercising more than I ever have. In the dream, my doctor gave me medicine to correct this and I would be fine if I took this medicine. In waking life, he did ask about diet and I didn't tell him how much I'm dieting; he's never asked about exercise. I guess I should tell him about diet and exercise, huh?" (Barrett, 1993, p. 119) This dream does seem to reflect her concern about not telling the whole story to her doctor. But the solution to the problem--telling the doctor about her dieting and exercising--is arrived at in waking life by thinking about the dream scene wherein the doctor tells her what is wrong and gives her medicine.
The second dreamer also has a medical problem: "The problem is whether I had taken my medicine. I'm supposed to take just one of these pills a day; it's bad if I take more than one or miss one. I couldn't remember this day if I had taken it and I was really worried." She reports the following dream: "I was drinking water and swallowing pills over and over; it just went on with me drinking and taking pills for a long time" (Barrett, 1993, p. 119). Once again, this dream seems to reflect an emotional preoccupation, but swallowing far more pills than she is supposed to take hardly seems to be a "solution" to the problem. Instead, the dream has that slightly unlikely and dramatic quality--wolfing down all those pills-- that makes dreaming distinctive.
In a few cases in Barrett's study, the alleged solution seems to come during waking life in reaction to the dream, as Blagrove (1992; 1996 ) would predict. This point is best demonstrated by a seemingly metaphoric dream that supposedly indicated the dreamer should go to graduate school in Texas or California, because "the light seems to be further west" than Massachusetts, her home state: Problem: I have applied to two clinical psychology programs and two in industrial psychology because I just can't decide which field I want to go into. Dream: A map of the United States. I am in a plane flying over this map. The pilot says we are having engine trouble and need to land and we look for a safe place on the map, indicated by a light. I ask about Massachusetts, which we seem to be over right then, and he says all of Massachusetts is very dangerous. The lights seem to be further west" (Barrett, 1993, p. 118).
The dreamer then reports that she "wakes up and realizes that my two clinical schools are both in Massachusetts, where I have spent my whole life and where my parents live," whereas both of the industrial psychology programs are far away. She thinks the dream is telling her that "getting away is more important than which kind of program I go to" (Barrett, 1993, p. 118). But the realization comes upon awakening, and it is unlikely that the dreamer did not understand that the industrial programs were both far from home.
Thus, there is little or no systematic evidence for the idea that dreams very often contain the solution to problems. The idea is therefore is supported with anecdotal examples of solutions to scientific problems or inventions that supposedly came from dreams, but unfortunately there is no way to verify such claims. Barrett (2001) assembles all the past anecdotes in a popular presentation of the theory. Some of the most famous anecdotes seem to have emerged during reverie or drug states. Others are only known through second-hand testimony. She then brings forth examples of her own.
Barrett also presents cases where musicians have been inspired to creative efforts by music they heard in their dreams. There are also examples of writers and poets who have used their dreams as the basis for their waking work. These examples show that dreams can be inspirational and often contain content that can the core of new creative work in waking life, but this is not the same thing as solving a problem. There is no evidence that these musicians, writers, and poets were searching for plots or trying to solve a problem when they had these dreams. Creative thinking during sleep does not mean that dreams have a problem-solving function.
When all is said and done, there is only occasional anecdotal evidence for the idea that recalled dreams have any role in solving or detecting problems. This evidence is not impressive when it is arrayed against the small percentage of dreams that are recalled and the even smaller percentage of recalled dreams that might be construed as having a solution to a problem. Dreams may on occasion be useful to waking consciousness as a basis for thinking about problems in a new way, or as a basis for discussing personal problems, as some clinical research shows (Fiss, 1991; Greenberg et al., 1992). And dreams that have a dramatic emotional impact create a strong subjective sense that they must have a useful message. However, it does not follow from clinical usefulness or a waking impression of importance that dreaming has an adaptive function (Antrobus, 1993).
Do Unrecalled Dreams Have A Function?
Recognizing the problems with theories that attribute a waking function to the very few dreams that are recalled, there are now several theorists who claim that dreaming has a function even when dreams are not recalled. Drawing on an analogy with computers, one pair of theorists claims that dreaming clears out useless memories from the day before (Crick & Mitchison, 1983; Crick & Mitchison, 1986), Drawing on speculations in evolutionary psychology, others claim that dreams have a social-learning (Brereton, 2000) or threat-simulation function (Revonsuo, 2000).
The idea that dreams help rid the brain of useless recent memories is based on the assumption that the pontine instigators of REM are producing random, meaningless imagery. This claim depends crucially on the contested claim that dreaming is confined to REM, but is also challenged by three other findings. First, only about half of recalled dreams have even one slight reference to recent events, which is contrary to what the theory would predict (Botman & Crovitz, 1989; Harlow & Roll, 1992). Second, dreams are more coherent and related to waking thoughts than the theory would predict. Third, the findings on the consistency of dream content over years and decades, and especially negative dream content, is opposite of what this theory would predict; there is no reason to believe that repetitive dream content clears out useless memories (Domhoff, 1996, and Chapter 5).
The rehearsal theories put forth by Brereton (2000) and Revonsuo (2000) attempt to build on the evidence for the consolidation of procedural memories during REM (Smith, 1995), but memory consolidation is not the same thing as new learning during sleep through mental rehearsal, for which there is no evidence. And even if there is memory consolidation during sleep, it does not follow that dreaming is also occurring (Antrobus, 1993; Flanagan, 2000b).
The rehearsal theories assume that REM and dreaming are one and the same in all mammals, which is a very dubious assumption. They use the evidence for memory consolidation to support this assumption, but there is a strong case that animals do not have the conceptual capacities to dream (Foulkes, 1983). The most notable claim for animal dreaming is based on the searching and sexual movements by decorticated cats during REM, but stereotypic behavioral routines in decorticated animals are not evidence for dreaming, which is a cortical function, and in any event these movements also happen when the cats are awake (Blagrove, 2000).
The intriguing idea that only human beings dream is greeted with great surprise and rejection by many dream theorists. They are not impressed with the argument that the lack of the cognitive skills for dreaming in young children suggests that less developed animals probably do not dream. They note that there is no known way to prove this claim, but ignore the fact that there is no way to prove their claims either. They continue to accept the movements by decorticated cats as evidence for their view even though there is now great doubt that these movements relate to dreams given that this dreaming would have to be taking place in the brainstem. They seem to recognize that the stakes are very great here. If only human beings over the age of 5 or 6 are able to dream, then evolutionary theories of dream function go out the window.
Animal dreaming aside, there are further problems with Revonsuo's version of the rehearsal theory. It stretches the imagination to think that the one-trial system of fear conditioning that has been present in the brain since the evolution of reptiles needs to be primed by dreaming. The low levels of dreaming in young children, and the benign nature of the few dreams they do have, do not support Revonsuo's claim that dreams are useful in helping children to learn to be vigilant against dangerous animals (Foulkes, 1999). His further claim that trauma may stimulate dreaming in children does not seem plausible in the light of Foulkes's (1982) finding that children with tense home environments did not report more dreams than other children. His vision of the "ancestral environment" as filled with dangerous predators does not seem credible in the light of primate evidence that fellow members of the group are the biggest threat.
Revonsuo's theory does not explain the large amount of dream content that does not relate to threat and aggression (Zadra & Donderi, 2000b). He overstates the amount of physical aggression in dreams by downplaying the distinction between physical and nonphysical aggression in the Hall/Van de Castle coding system. Finally, the theory ignores the fact that nightmarish attack dreams are debilitating for many people, making them less fit for daily life (Levin, 2000; Nielsen & Germain, 2000).
Building on the general psychodynamic idea that dreaming is an attempt to deal with personal problems, Hartmann (1998) argues more specifically that the function of dreams is to help people work through traumatic experiences, whether the dreams are recalled or not. According to his theory, dreams deal with a trauma by putting it in many different mental contexts within the "safe place" of sleep, where psychological "connections" can be made without any personal danger. Studies showing that free associations are more unlikely ("distant") and imagistic in the waking period shortly after REM than NREM lend support to this aspect of the theory (Fiss, Ellman, & Klein, 1969; Fiss, Klein, & Bokert, 1966).
Although Hartmann's theory does not require that dreams be recalled, the evidence for it rests on alleged changes in the dreams that trauma victims happen to recall. First, Hartmann assumes that the recalled dreams reflect the trauma, often indirectly through what he calls a "contextualizing metaphor." These striking images, such as the approach of a tidal wave, epitomize the way in which these dreams are filled with intimations of disaster, misfortunes, violence, and strong negative emotions. Second, he asserts that the post-trauma dreams become less negative over time, suggesting that the trauma is being dealt with by the dream process. However, the evidence for both of these claims is weak. Although the dream examples he presents are filled with negative emotions, his coding system for emotions is unproven and he has no normative data to show that the dreams are in fact more negative than the dreams of those who have not suffered traumas (Domhoff, 1999, for a full critique of Hartmann's method and evidence) . For example, if the negative emotions percent in the Hall/Van de Castle norms is taken as a baseline, then it can be expected that 80% of the emotions in any dream sample will be negative. The same figure has been reported in three later studies that use dream reports from different eras, the sleep laboratory, and Canada (Hall, Domhoff, Blick, & Weesner, 1982; Roussy, Raymond, & De Koninck, 2000b; Tonay, 1990/1991).
Hartmann also notes the large amount of aggression and other negative events in the dreams of trauma victims, but he does not provide any systematic studies. If Hall/Van de Castle normative findings are once again taken as a baseline, then 23 percent of men's dreams and 15 percent of women's dreams have at least one chase, attack, or murder, and 33 percent of men's dreams and 36 percent of women's dreams have at least one misfortune. Even more to the point of Hartmann's studies, which use five recent dreams from each trauma victim, 69 percent of the men and 54 percent of the women in the Hall/Van de Castle normative sample had at least one chase, attack, or murder in the five dreams they contributed.
Hartmann's theory crucially hinges on the degree to which the dreams of trauma victims change over time. He asserts that he has found positive changes in several dream series, but he presents no systematic data on declines in particular negative themes, nor in any content categories that parallel the categories for aggressions, misfortunes, failures, and negative emotions in the Hall/Van de Castle system. Nor has he reported any comparisons with possible changes in the dreams of people who have not suffered traumas. Given the general consistency of dreams over months and decades that has been demonstrated in this book, along with the possibility that the rate of aggression in dreams may decline with age, there is reason to be skeptical about his claims until more systematic findings with an adequate coding system are presented. Such studies might show that the dream content actually stays the same, but that the dreamer is less upset in the face of it. Ideally, future tests of the theory would include dreams from before the traumatic event to provide the best possible baseline.
As do other clinically derived theories of dreaming, Hartmann's theory assumes that the conceptual metaphors so important in waking thought are also operating in dreams. However, there is still no solid evidence for this claim. Even if he were able to answer the empirical objections discussed in the three previous paragraphs, the metaphoric basis of his theory would remain as an untested assumption.
If the weaknesses of all theories of dream function are combined with the evidence that dreaming is a process that occurs only in human beings, and only after the age of 5 or 6, then it seems highly unlikely that dreams have any adaptive function. They are the by-product of two great evolutionary developments, sleep and complex cognitive processes. These minimalist conclusions join with empirical findings on the actual nature of dream content to suggest that cognitive psychology may be the best starting point for developing an adequate model of dreams. Dreaming is a form of thinking during sleep, and dreams contain at least some psychological meaning, but it does not follow from these conclusions that dreams also have an adaptive function. In fact, dreaming may be an evolutionarily recent form of thinking, not the primitive process it is usually assumed to be.
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