In lucid dreams the dreamer is aware of dreaming and often able to influence the ongoing dream content. Lucid dreaming is a learnable skill and a variety of techniques is suggested for lucid dreaming induction. This systematic review evaluated the evidence for the effectiveness of induction techniques. A comprehensive literature search was carried out in biomedical databases and specific resources. Thirty-five studies were included in the analysis , of which 26 employed cognitive techniques, 11 external stimulation and one drug application. (...) The methodological quality of the included studies was relatively low. None of the induction techniques were verified to induce lucid dreams reliably and consistently, although some of them look promising. On the basis of the reviewed studies, a taxonomy of lucid dream induction methods is presented. Several methodological issues are discussed and further directions for future studies are proposed. (shrink)

Biological realism (Revonsuo, 2001, 2006) states that dreaming is a biological phenomenon and therefore explainable in naturalistic terms, similar to the explanation of other biological phenomena. In the biological sciences, the structure of explanations can be described with the help of a framework called 'multilevel explanation'. The multilevel model provides a context that assists to clarify what needs to be explained and how, and how to place different theories into the same model. Here, I will argue that the multilevel framework (...) would be useful when we try to construct scientific explanations of dreaming. (shrink)

The threat simulation theory of dreaming states that dream consciousness is essentially an ancient biological defence mechanism, evolutionarily selected for its capacity to repeatedly simulate threatening events. Threat simulation during dreaming rehearses the cognitive mechanisms required for efficient threat perception and threat avoidance, leading to increased probability of reproductive success during human evolution. One hypothesis drawn from TST is that real threatening events encountered by the individual during wakefulness should lead to an increased activation of the system, a threat simulation (...) response, and therefore, to an increased frequency and severity of threatening events in dreams. Consequently, children who live in an environment in which their physical and psychological well-being is constantly threatened should have a highly activated dream production and threat simulation system, whereas children living in a safe environment that is relatively free of such threat cues should have a weakly activated system. We tested this hypothesis by analysing the content of dream reports from severely traumatized and less traumatized Kurdish children and ordinary, non-traumatized Finnish children. Our results give support for most of the predictions drawn from TST. The severely traumatized children reported a significantly greater number of dreams and their dreams included a higher number of threatening dream events. The dream threats of traumatized children were also more severe in nature than the threats of less traumatized or non-traumatized children. (shrink)

Repression has become an empirical fact that is at once obvious and problematic. Fragmented clinical and laboratory traditions and disputed terminology have resulted in a Babel of misunderstandings in which false distinctions are imposed (e.g., between repression and suppression) and necessary distinctions not drawn (e.g., between the mechanism and the use to which it is put, defense being just one). “Repression” was introduced by Herbart to designate the (nondefensive) inhibition of ideas by other ideas in their struggle for consciousness. Freud (...) adapted repression to the defensive inhibition of “unbearable” mental contents. Substantial experimental literatures on attentional biases, thought avoidance, interference, and intentional forgetting exist, the oldest prototype being the work of Ebbinghaus, who showed that intentional avoidance of memories results in their progressive forgetting over time. It has now become clear, as clinicians had claimed, that the inaccessible materials are often available and emerge indirectly (e.g., procedurally, implicitly). It is also now established that the Ebbinghaus retention function can be partly reversed, with resulting increases of conscious memory over time (hypermnesia). Freud's clinical experience revealed early on that exclusion from consciousness was effected not just by simple repression (inhibition) but also by a variety of distorting techniques, some deployed to degrade latent contents (denial), all eventually subsumed under the rubric of defense mechanisms (“repression in the widest sense”). Freudian and Bartlettian distortions are essentially the same, even in name, except for motive (cognitive vs. emotional), and experimentally induced false memories and other “memory illusions” are laboratory analogs of self-induced distortions. Key Words: avoidance; Bartlett; defense; denial; distortion; Ebbinghaus; false-memories; Freud; inhibition; repression; suppression. (shrink)

The problem of dream skepticism – i.e., the problem of what can justify one’s belief that they are not dreaming – is one of the most famous problems in philosophy. I propose a way of responding to the problem which is available if one subscribes to the theory that the sensory experiences that we have in dreams consist of images (as opposed to false percepts). The response exploits a particular feature of imagination, viz., that it is not possible to simultaneously (...) have two separate imagistic experiences in the same modality. (shrink)

Although we are beginning to understand the neurocognitive processes that underlie the emergence of dreaming, what accounts for the bizarre phenomenology of dreams remains debated. I address this question by comparing dreaming with waking mind wandering and challenging previous accounts that utilize bizarreness to mark a sharp divide between conscious experiences in waking and sleeping. Instead, I propose that bizarreness is a common, non-deficient feature of spontaneous offline simulations occurring across the sleep-wake cycle and can be tied to the specific (...) characteristics of spontaneous thought as being dynamic, unconstrained, (hyper)associative and highly variable in content. Rather than misrepresenting waking reality, bizarreness can be employed to investigate the very building blocks of spontaneous cognition. The absence of bizarreness in thought processes is imposed by automatic and deliberate cognitive constraints. By contrast, thought and memory processes operating on their own without such constraints are inherently marked by different degrees and types of bizarreness. (shrink)

Although the sense of agency is often reduced if not absent in dreams, our agentive dream experiences can at times be similar to or enhanced compared to waking. The sense of agency displayed in dreams is perplexing as we are mostly shut off from real stimulus whilst asleep. Theories of waking sense of agency, in particular, comparator and holistic models, are analysed in order to argue that despite the isolation from the real environment, these models can help account for dream (...) experience. The dreamer might feel an increased sense of control of their dream bodies and a sense that they can directly control elements of the dream world. Such experiences may at times be caused by superstitious or delusional thinking due to altered cognition and changes to the sleeping brain. Here it is argued that some such experiences are akin to specific waking delusions, such as delusions of grandeur, with similar cognitive features. However, other instances of increased sense of agency in dreaming appear to be sui generis and nothing like what we experience when awake. Lucid control dreams, in which the dreamer realises that they are dreaming and that they can control the dream environment, are examples of such an experience although further nuance is required to account for their specific cognitive attributes. Future empirical research should focus on controlled dream reporting conditions in order to clarify the types of experience that occur and determine the relevant cognitive mechanisms that relate to each type. (shrink)

When we dream, it is often assumed, we are isolated from the external environment. It is also commonly believed that dreams can be, at times, accurate, convincing replicas of waking experience. Here I analyse some of the implications of this view for an enactive theory of conscious experience. If dreams are, as described by the received view, “inactive”, or “cranially envatted” whilst replicating the experience of being awake, this would be problematic for certain extended conscious mind theories. Focusing specifically on (...) Alva Noë’s enactive view, according to which the vehicles of perceptual experience extend beyond the brain, I argue that dreams are a quandary. Noë’s view is that dreaming is consistent with enactivism because even if dreams are inactive and shut off from the external environment, they are not “full-blown” perceptual consciousness, and also, there is some reason to reject the inactive claim. However, this view rests on an unjustified and reductive account of dreams which is not supported... (shrink)

Dreaming is often characterized as lacking high-order cognitive skills. In two studies, we test the alternative hypothesis that the dreaming mind is highly similar to the waking mind. Multiple experience samples were obtained from late-night REM sleep and waking, following a systematic protocol described in Kahan . Results indicated that reported dreaming and waking experiences are surprisingly similar in their cognitive and sensory qualities. Concurrently, ratings of dreaming and waking experiences were markedly different on questions of general reality orientation and (...) logical organization . Consistent with other recent studies , experiences sampled from dreaming and waking were more similar with respect to their process features than with respect to their structural features. (shrink)

This study aimed to find out whether differences in the reported colour of dreams can be attributed to the influence of black and white media or to methodological issues. Two age groups, with different media experience, were compared on questionnaire and diary measures of dream colour. Analysis revealed that people who had access to black and white media before colour media experienced more greyscale dreams than people with no such exposure, and there were no differences between diary and questionnaire measures (...) of dream colour. Moreover, there were inter-group differences in the recall quality of colour and black and white dreams that point to the possibility that true greyscale dreams occur only in people with black and white media experience. (shrink)

There is wide agreement among dream researchers that emotional memories are activated during dreaming and that emotions play an important role in the thematic development of the dream. In accordanc...

The content of dreams and changes to the self were investigated in students moving to University. In study 1, 20 participants completed dream diaries and memory tasks before and after they had left home and moved to university, and generated self images, “I am…” statements , reflective of their current self. Changes in “I ams” were observed, indicating a newly-formed ‘university’ self. These self, images and related autobiographical knowledge were found to be incorporated into recent dreams but not into dreams (...) from other periods. Study 2 replicated these findings in a different sample . We suggest that these data reflect a period of self-consolidation in which new experiences and self images are incorporated into autobiographical memory knowledge structures representing personal goals during sleep. (shrink)

This study examined the laboratory dream content reported by 14 patients with schizophrenia and 15 controls, with a focus on reports obtained from NonREM sleep. Both the controls’ and patients’ frequency of dream recall following awakenings from NonREM and REM sleep were similar to values reported for healthy participants. Patients’ NonREM sleep narratives were shorter than those from controls. When compared to their reports from REM sleep, both groups’ NonREM sleep reports included significantly fewer words and reportable items. The controls (...) were more likely to report a subjective feeling of bizarreness for their REM sleep reports as compared to their NonREM sleep reports. This difference was not observed in patients with schizophrenia. Taken together, these findings suggest few differences between the NonREM sleep mentation of patients with schizophrenia and of controls and that sleep stage cognitive style is comparable in both groups, with NonREM sleep reports being more thought-like, less elaborate and bizarre than REM sleep reports. (shrink)

The relationship between dream content and waking life experiences remains difficult to decipher. However, some neurobiological findings suggest that dreaming can, at least in part, be considered epiphenomenal to ongoing memory consolidation processes in sleep. Both abnormalities in sleep architecture and impairment in memory consolidation mechanisms are thought to be involved in the development of psychosis. The objective of this study was to assess the continuity between delusional contents and dreams in acutely psychotic patients. Ten patients with a single fixed (...) and recurring delusional content were asked to report their dreams during an acute psychotic break. Sixteen judges with four different levels of acquaintance to the specific content of the patients’ delusions were asked to group the dreams, expecting that fragments of the delusional thought would guide the task. A mathematical index was developed in order to compare correct groupings between the four groups of judges. Most judges grouped the dreams slightly above chance level and no relevant differences could be found between the four groups [F = 1.297; p = n.s.]. Scoring of dreams for specific delusional themes suggested a continuity in terms of dream and waking mentation for two contents . These findings seem to suggest that at least some delusional contents recur within patients’ dreams. Future studies will need to determine whether such continuity reflects ongoing consolidation processes that are relevant to current theories of delusion formation and stabilization. (shrink)

BackgroundDreams can be affected by recent life events and long-term life experiences. Previous evidence has shown that childhood adverse experiences are associated with sleep quality and dream experiences.ObjectiveThe aim of this study was to explore the relationship between childhood adverse experiences and dream content in adults.Participants and SettingA total of 163 participants without current or past physical or mental disorders aged between 18 and 35 were screened in the hospital. Among them, 120 subjects who completed a dream content record at (...) home and whose anxiety and depression levels and sleep quality were within the normal range were included in the data analysis.MethodsA cross-sectional survey was conducted from June 2017 to December 2019. Dream content for 10 consecutive days was recorded by the participants and coded by the Hall and Van de Castle coding system. Childhood adversity was assessed by the Childhood Trauma Questionnaire. In the end, 719 dreams out of 626 nights for 120 participants were included in the data analysis, gender differences between groups were analyzed using t-tests or U tests, and Spearman’s partial correlation and multiple linear regression were used to investigate the relationship between childhood trauma and dream content.ResultsChildhood adversity was associated with characters, friendly interactions, and objects in dream content. Regression models of childhood adversity predicting characters and objects in dream content were constructed. There were no gender differences in general demographic data, sleep quality, emotional state, childhood adversity, dream recall frequency, or dream content.ConclusionChildhood adversity is associated with adult dream content. (shrink)

Music in dreams is rarely reported in scientific literature, while the presence of musical themes in dreams of famous musicians is anecdotally reported. We did a systematic investigation to evaluate whether the occurrence of musical dreams could be related to musical competence and practice, and to explore specific features of dreamt pieces. Thirty-five professional musicians and thirty non-musicians filled out a questionnaire about the characteristics of their musical activity and a structured dream log on the awakening for 30 consecutive days. (...) Musicians dream of music more than twice with respect to non-musicians; musical dreams frequency is related to the age of commencement of musical instruction, but not to the daily load of musical activity. Nearly half of the recalled music was non-standard, suggesting that original music can be created in dreams. (shrink)

For five individuals, a social network was constructed from a series of his or her dreams. Three important network measures were calculated for each network: transitivity, assortativity, and giant component proportion. These were monotonically related; over the five networks as transitivity increased, assortativity increased and giant component proportion decreased. The relations indicate that characters appear in dreams systematically. Systematicity likely arises from the dreamer's memory of people and their relations, which is from the dreamer's cognitive social network. But the dream (...) social network is not a copy of the cognitive social network. Waking life social networks tend to have positive assortativity; that is, people tend to be connected to others with similar connectivity. Instead, in our sample of dream social networks assortativity is more often negative or near 0, as in online social networks. We show that if characters appear via a random walk, negative assortativity can result, particularly if the random walk is biased as suggested by remote associations. (shrink)