Dreams, Misc

This paper analyzes the ontology and epistemology of time in Lucretius’ De rerum natura. It uses the physiology of perception as well as epistemology to shed new light on the metaphysics. It presents an exegesis-based interpretation of the nature of time and of its perception, both arguing for and refining this interpretation by showing its explanatory power. The paper shows that Lucretius represents the perception of time or sensus temporis as a distinct sensory faculty, reconstructs how it emerges and operates, (...) and relates it to his account of perception more generally. The sense of time in turn is seen to explain aspects of related faculties, including thought and sight, and cases of apparent simultaneity. The paper thus contributes to, among other things, our understanding of the speed of perception and Lucretius’ account of the nature of time itself — arguing that Lucretius represents time as both continuous (not atomic) and real, as well as something perceived. (shrink)

The dream-lag effect refers to there being, after the frequent incorporation of memory elements from the previous day into dreams , a lower incorporation of memory elements from 2 to 4 days before the dream, but then an increased incorporation of memory elements from 5 to 7 days before the dream. Participants kept a daily diary and a dream diary for 14 days and then rated the level of matching between every dream report and every daily diary record. Baseline matching (...) was assessed by comparing all dream reports to all diary records for days that occurred after the dream. A significant dream-lag effect for the 5–7 day period, compared to baseline and compared to the 2–4 day period, was found. This may indicate a memory processing function for sleep, which the dream content may reflect. Participants’ and three independent judges’ mean ratings also confirmed a significant day-residue effect. (shrink)

Waking mind functioning comprises conscious and unconscious processes, with the latter being experimentally demonstrated by parapraxes and recent findings showing the active suppression of unwanted memories. According to psychoanalytic theory, these repression phenomena involve an unconscious censorship process. Today, neurobiological results show that this process seems to occur during waking rather than during the dreaming sleep stage.

From the perspective of modern dream research, Freud's hypotheses regarding repression and dreaming are difficult to evaluate. Several studies indicate that it is possible to study these topics empirically, but it needs a lot more empirical evidence, at least in the area of dream research, before arriving at a unified theory of repression.

An ongoing assumption made by sleep researchers is that since dreams are more often recalled on awakening from rapid eye movement sleep, dreams must occur more often during this stage of sleep. An alternative hypothesis is that cognition occurs throughout sleep, but the recall of this mentation differs on awakening. When a dream is not reported on awakening, there is no method of establishing whether it did not happen or was forgotten. The aim of the present study was to investigate (...) this issue using an eye movement signal verification technique. Participants were instructed to produce an EM signal whenever they heard a tone. Tones were presented at increasing volume during Stage 2 and REM sleep until EM signal verification was observed. Ninety seconds after signal verification, participants were awakened and asked if they remembered hearing the tone or responding with the EM signal. Such recollection of signal verified tone presentations was significantly less after Stage 2 sleep compared to REM sleep presentations. Furthermore, SVT recall was significantly correlated with reported dream recall frequency, suggesting the same processes involved in recalling SVTs might also underlie dream recall. (shrink)

This study tested the two main neurocognitive models of dreaming by using cognitive data elicited from REM sleep in normals and narcoleptics. The two models were the ''activation-only'' view which holds that, in the context of sleep, overall activation of the brain is sufficient for consciousness to proceed in the manner of dreaming (e.g., Antrobus, 1991; Foulkes, 1993; Vogel, 1978); and the Activation, Input source, Modulation (AIM model), which predicts that not only brain activation level but also neurochemical modulatory systems (...) exert widespread effects upon dreaming (Hobson & McCarley, 1977; Hobson, Pace-Schott, & Stickgold, 2000). Mental activity was studied in nocturnal REM in 15 narcoleptics and 9 normal healthy persons and in REM at the onset of daytime naps and nighttime sleep (SOREM) in narcoleptics. The study was performed in the subjects' homes, using instrumental awakenings and ambulatory polysomnographic techniques, and focused upon visual vividness, mentation report length, improbable and discontinuous bizarre features, and reflective consciousness. Within each subject group, most cognitive variables tended to fluctuate in line with expected variations in circadian activation level. When comparing the cognitive variables between the two groups, reflective consciousness was clearly highest in narcoleptics, whereas improbabilities and discontinuities were lower, with mentation report length and visual vividness differing less between the groups. These findings are consistent with the AIM model of sleep mentation, but not with the activation-only model. (shrink)

Several theories claim that dreaming is a random by-product of REM sleep physiology and that it does not serve any natural function. Phenomenal dream content, however, is not as disorganized as such views imply. The form and content of dreams is not random but organized and selective: during dreaming, the brain constructs a complex model of the world in which certain types of elements, when compared to waking life, are underrepresented whereas others are over represented. Furthermore, dream content is consistently (...) and powerfully modulated by certain types of waking experiences. On the basis of this evidence, I put forward the hypothesis that the biological function of dreaming is to simulate threatening events, and to rehearse threat perception and threat avoidance. To evaluate this hypothesis, we need to consider the original evolutionary context of dreaming and the possible traces it has left in the dream content of the present human population. In the ancestral environment human life was short and full of threats. Any behavioral advantage in dealing with highly dangerous events would have increased the probability of reproductive success. A dream-production mechanism that tends to select threatening waking events and simulate them over and over again in various combinations would have been valuable for the development and maintenance of threat-avoidance skills. Empirical evidence from normative dream content, children's dreams, recurrent dreams, nightmares, post traumatic dreams, and the dreams of hunter-gatherers indicates that our dream-production mechanisms are in fact specialized in the simulation of threatening events, and thus provides support to the threat simulation hypothesis of the function of dreaming. Key Words: dream content; dream function; evolution of consciousness; evolutionary psychology; fear; implicit learning; nightmares; rehearsal; REM; sleep; threat perception. (shrink)

The five authors vary in the degree to which the recent neuroscience of the REM state leads them towards multiple dimensions and forms of dreaming consciousness (Hobson et al.; Nielsen; Solms) or toward all-explanatory single factor models (Vertes & Eastman, Revonsuo). The view of the REM state as a prolongation of the orientation response to novelty fits best with the former pluralisms but not the latter monisms. [Hobson et al.; Nielsen; Revonsuo; Solms; Vertes & Eastman].

It has been a common finding among modern theorists that dreams about the deceased are a healthy attempt by the bereaved to resolve conflicts, surrender attachments, and deal with feelings of abandonment . In this paradigm, the dream image has been seen as an internally generated memory trace, or introjection. In contrast, pre-scientific cultures and modern tribal peoples have held longstanding beliefs about the veracity of these communications from the dead. This study employed a qualitative research design using a phenomenological (...) method to further elucidate this phenomenon. Five subjects who had experienced the appearance of the deceased as a dream image during the period of mourning were interviewed. It was shown that the dreams did assist the bereaved in their grief process. It was also evidenced that the image of the deceased, in most cases, developed as well. From this standpoint, the author speculated that the image of the deceased may be conceptualized metaphorically. That is, as neither a pure introjection on the part of the bereaved, nor as a substantive visitation, but as something that is created from what lies between the living and the dead. This co-created image can then be seen as a rich source of information for understanding the relationship dynamics in life as well as in death. (shrink)

Consciousness can be studied only if subjective experience is documented and quantified, yet first-person accounts of the effects of brain injury on conscious experience are as rare as they are potentially useful. This report documents the alterations in waking, sleeping, and dreaming caused by a lateral medullary infarct. Total insomnia and the initial suppression of dreaming was followed by the gradual recovery of both functions. A visual hallucinosis during waking that was associated with the initial period of sleep and dream (...) suppression is described in detail. Since the changes in sleep and their recovery are comparable to results of animal experiments, it can be concluded that damage to the medullary brain stem causes extreme but short-lived alterations in conscious state and that substantial recovery occurs even though the damage to the brain stem endures. (shrink)

The Matrix trilogy is unique among recent popular films in that it is constructed around important philosophical questions--classic questions which have fascinated philosophers and other thinkers for thousands of years. Editor Christopher Grau here presents a collection of new, intriguing essays about some of the powerful and ancient questions broached by The Matrix and its sequels, written by some of the most prominent and reputable philosophers working today. They provide intelligent, accessible, and thought-provoking examinations of the philosophical issues that support (...) the films. Philosophers Explore The Matrix includes an introduction that surveys the use of philosophical ideas in the film. Topics that the contributors tackle include: how a collaborative dream could differ from hallucination, the difference between the Matrix and the "real" world; why living in the Matrix would be considered "bad"; the similarities between the Matrix and Plato's Cave; the moral status of artificially created beings, whether one can behave immorally in illusory circumstances, and the true nature of free will and responsibility. This volume also includes an appendix of classic philosophical writing on these issues by Plato, Berkeley, Descartes, Putnam, and Nozick. Philosophers Explore The Matrix will fascinate any fan of the films who wants to delve deeper into their themes, as well as any student of philosophy who desires an accessible entry into this challenging and profoundly vital world of ideas. (shrink)

Zadra, Desjardins, and Marcotte tested several predictions derived from the Threat Simulation Theory of dreaming in a large sample of recurrent dreams. In response to these findings, Valli and Revonsuo presented a commentary outlining alternate conceptualizations and explanations for the results obtained. We argue that many points raised by Valli and Revonsuo do not accurately reflect our main findings and at times present a biased assessment of the data. In this article, we provide necessary clarifications and responses to each one (...) of their main points of discussion. (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)

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)

This study investigated the relationship between dream emotion and dream character identification. Thirty-five subjects provided 320 dream reports and answers to questions on characters that appeared in their dreams. We found that emotions are almost always evoked by our dream characters and that they are often used as a basis for identifying them. We found that affection and joy were commonly associated with known characters and were used to identify them even when these emotional attributes were inconsistent with those of (...) the waking state. These findings are consistent with the finding that the dorsolateral prefrontal cortex, associated with short-term memory, is less active in the dreaming compared to the wake brain, while the paleocortical and subcortical limbic areas are more active. The findings are also consistent with the suggestion that these limbic areas have minimal input from the dorsolateral prefrontal cortex in the dreaming brain. (shrink)

This review describes central difficulties in the interdisciplinary study of dreaming, summarizes Jouvet's account of his role in the history of modern dream science, queries his positive speculations on the semantics of dreaming, and suggests work for historians of neuroscience.

A minority position is presented in which evidence will be cited from the Hobson, Solms, Revonsuo, and Nielsen target articles and from other sources, supporting major tenets of Freud's theory of dreaming. Support is described for Freud's view of dreams as meaningful, linked to basic motivations, differing qualitatively in mentation, and wish-fulfilling. [Hobson et al.; Nielsen; Revonsuo; Solms].

Revonsuo argues that the biological function of dreaming is to simulate threatening events and to rehearse threat avoidance behaviors. He views recurrent dreams as an example of this function. We present data and clinical observations suggesting that (1) many types of recurrent dreams do not include threat perceptions; (2) the nature of the threat perceptions that do occur in recurrent dreams are not always realistic; and (3) successful avoidance responses are absent from most recurrent dreams and possibly nightmares. [Hobson et (...) al.; Revonsuo]. (shrink)

The notion of simulation in dreaming of threat recognition and avoidance faces difficulties deriving from (1) some typical characteristics of dream artifacts (some “surreal,” some not) and (2) metaphysical issues involving the need for some representation in the theory of a perspective subject making use of the artifact. [Hobson et al.; Revonsuo].

The pharmacological literature on negative dream experiences is reviewed with respect to Revonsuo's threat rehearsal theory of dreaming. Moderate support for the theory is found, although much more work is needed. Significant questions that remain include the precise role of acetylcholine in the generation of negative dream experiences and dissociations between the pharmacology of waking fear and anxiety and threatening dreams. [Revonsuo].

New findings point to a role for mesolimbic DA circuits in the generation of dreaming. We disagree with Solms about these structures having an exclusive role in generating dreams. We review data suggesting that dreaming can be interrupted at different levels of processing and that anterior-subcortical lesions associated with dream cessation are unlikely to produce selective hypodopaminergic dynamic impairments. [Hobson et al.; Nielsen; Solms].

The “problem” of dreaming in NREM sleep continues to challenge models that propose a causal relationship between REM mechanisms and the psychological features of dreaming. I suggest that, ultimately, efforts to identify correspondences among multiple levels of analysis will be more productive for dream theory than attempts to reduce dreaming to any one level of analysis. [Hobson et al. ; Nielsen].

In this manuscript Hobson et al. propose a model exploring qualitative differences between the three states of consciousness, waking, NREM sleep, and REM sleep, in terms of state-related brain activity. The model consists of three factors, each of which varies along a continuum, creating a three-dimensional space: activation (A), information flow (I), and mode of information processing (M). Hobson has described these factors previously (1990; 1992a). Two of the dimensions, activation and modulation, deal directly with subcortical influences upon cortical structures (...) – the reticular activation system, with regard to the activation dimension and the locus coeruleus and the pontine raphe neuclei, with regard to the modulation dimension. The focus of this review is a further exploration of the interaction between dreaming and the cortical and subcortical structures relevant to REM sleep eye movements. [Hobson et al. ]. (shrink)

Dreaming is a statistically robust cognitive correlate of REM sleep, but all of its formal features may occur in other states of sleep and even in waking, especially during fantasy. In order to test the hypothesis that the brain basis of such cognitive features as dream bizarreness is to be found in REM sleep neurophysiology, it is critical to quantify bizarreness in dreams and other mental states and to analyze the data with respect to both the magnitude and the kind (...) of bizarreness so measured. Any differences in the cognitive dimensions are candidate correlates of REM sleep neurophysiology. Sixty pairs of home-based dream and fantasy reports were collected from 12 subjects and scored for bizarreness using a two-stage scoring system adapted from Hobson, Hoffman, Helfand, and Kostner . Our results show that bizarreness was twice as prevalent in dream reports as in wake-state fantasy reports of the same subjects. Further analysis of the reports also showed differences in other features including the number of persona and remoteness of time and place. (shrink)

While at first glance, it may appear atypical and perhaps inappropriate to begin a book review by briefly reviewing a previously published work of another author, this seeming incongruence is, in fact, only apparently inappropriate. In a chapter from an edited book critiquing cognition and dream research in which I focused on the uneasy relationship between mainstream cognitive psychology and dream research, I mainly critiqued Foulkes' work because, I suggested, he had "become a kind of spokesperson for the mainstream approach (...) to cognitive research as it applies to the study of dreaming" . Indeed, Foulkes' book has remained the most cogently theoretical and elegantly reasoned exemplar of the mainstream cognitive psychology laboratory approach to the study of dreaming. (shrink)

Part I of a two part article on the effect upon dreaming on physical illness briefly explores the historical medico-philosophical antecedents of the notion that dreams can be diagnostic of bodily disease. Modern sleep research findings relating REM sleep to physiologic changes are also explored. The controversy of whether dreams are merely the consequence of random brain activity or whether they are a valid psychological phenomenon is discussed. Six contemporary views of the function of REM sleep are outlined. A seventh (...) view of dreaming, that of a “cognitive monitoring system” is suggested. Like earlier historical notions, it is suggested that dreaming is a cognitive activity that processes bodily cues indicating illness or disease. Part II. presents a clinical compendium of dreams relating to Part I. (shrink)

A number of differences between the dreams of schizophrenia patients and those of healthy participants have been linked to changes in waking life that schizophrenia may cause. This way, the “continuity hypothesis” has become a standard way to relate dreaming and waking experiences in schizophrenia. Nevertheless, some of the findings in dream literature are not compatible with the continuity hypothesis and suggest some other ways how dream content and waking experiences could interact. Conceptually, the continuity hypothesis could be sharpened into (...) the “waking-to-dreaming” and the “dreaming-to-waking” hypotheses, whereas a less explored type of “discontinuity” could embrace the “compensated waking” and the “compensated dreaming” hypotheses. A careful consideration and empirical testing of each of those hypotheses may reveal a multiplicity of the ways how dreaming and waking life interact in schizophrenia. (shrink)

I discuss how the work in Walker's article adds to the considerable body of research on dreaming, sleep, and memory that appeared in the early days of modern sleep research. I also consider the issue of REM-independent and REM-dependent kinds of learning. This requires including emotional issues in our discussion, and therefore emphasizes the importance of studying and understanding dreams.

There has been no generally accepted cognitive definition of dreaming. An electrophysiologic correlate (REM sleep) has become its defining characteristic. Dreaming and REM sleep are complex states for which the Dreaming + REMs model is over-simplified and limited. The target articles in this BBS special issue present strong evidence for a dissociation between dreaming and REM sleep. [Hobson et al.; Nielsen, Revonsuo; Solms; Vertes & Eastman].