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Dreaming and lucidity in synaesthesia

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Abstract

Synaesthesia is a phenomenon in which the stimulation of one sensory modality automatically and consistently over time evokes a sensation in the same or a different modality in an idiosyncratic manner. In addition to pure sensory coupling, synaesthetes are characterized by cognitive peculiarities, such as abnormalities in perception, creativity, advantages in vocabulary, and vivid imagery. The present work is concerned with the question of the extent to which synaesthetes’ unusual perception is reflected in the dream state. Little is known about synaesthetes’ dreaming behaviour. Dreams are equated with the unconscious processing of the mind. An exception is a lucid dream, in which one is aware of their dreaming. In this dissociative state, it is possible to establish a connection to one's waking reality, wake up in a targeted manner, and control dream actions. Through self-report measures, participants (N=31 grapheme-colour-synaesthetes; N=32 non-synaesthetes) indicated their dream experiences and completed the Lucidity and Consciousness in Dreams scale (LuCiD scale). Synaesthetes reported lucid dream experiences significantly more often than non-synaesthetes. Qualitative differences were not found between both groups’ lucid dreamers. The two groups of lucid dreamers reported a majority of highly frequented lucidity. In addition, an association was identified between the early onset of lucid dreaming and higher values of the LuCiD scale. The results are discussed regarding the relevance of lucidity in synaesthesia within the context of consciousness research.

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People with synaesthesia not only have – by definition – unusual experiences (e.g., numbers triggering colour), they also have a different cognitive profile (e.g., in terms of their memory and perceptual abilities) and a bias towards certain interests and activities (e.g., towards the arts). However, virtually nothing is known about whether synaesthetes have an atypical personality profile. In this study, a standard measure of personality was administered (Big Five Inventory) along with two questionnaire measures of empathy. Synaesthetes, relative to demographically matched controls, reported higher levels of ‘Openness to Experience’ which is known to be related to imagination and artistic tendencies. They also reported higher levels of ‘Fantasizing’ on one of the empathy measures, which is conceptually related to Openness, although their self-reported empathy did not differ in other respects. In addition, synaesthetes reported lower levels of Agreeableness which we did not predict in advance.
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There is emerging evidence that the encoding of visual information and the maintenance of this information in a temporarily accessible state in working memory rely on the same neural mechanisms. A consequence of this overlap is that atypical forms of perception should influence working memory. We examined this by investigating whether having grapheme-color synesthesia, a condition characterized by the involuntary experience of color photisms when reading or representing graphemes, would confer benefits on working memory. Two competing hypotheses propose that superior memory in synesthesia results from information being coded in two information channels (dual-coding) or from superior dimension-specific visual processing (enhanced processing). We discriminated between these hypotheses in three n-back experiments in which controls and synesthetes viewed inducer and non-inducer graphemes and maintained color or grapheme information in working memory. Synesthetes displayed superior color working memory than controls for both grapheme types, whereas the two groups did not differ in grapheme working memory. Further analyses excluded the possibilities of enhanced working memory among synesthetes being due to greater color discrimination, stimulus color familiarity, or bidirectionality. These results reveal enhanced dimension-specific visual working memory in this population and supply further evidence for a close relationship between sensory processing and the maintenance of sensory information in working memory.
Article
This book is designed to advance both theory and practice in the psychological preparation of high-level sports performers. Seven aspects of psychological preparation are considered. Each discussion ends with a summary of the implications for future research and best practice. The authors explore the links between the practices elite athletes use during competition and theories which underlie psychological preparation for performance. This book develops a model of psychological preparation for elite sports performers incorporating research-to-practice orientation and a global perspective using evidence derived from North American, European, Australian and other research literatures in both general and sport psychology. This book is intended for sport psychologists, students and professionals with an interest in sport or high-level performance. (PsycINFO Database Record (c) 2012 APA, all rights reserved)
Article
Comments on S. J. McKelvie's (see record 1996-29151-001) review of the Vividness of Visual Imagery Questionnaire (VVIQ). Procedural issues that led McKelvie to underestimate the reliability and validity of the VVIQ are discussed. A new theoretical framework for mental imagery research is presented together with a revised form of the VVIQ, the VVIQ-2. (PsycINFO Database Record (c) 2012 APA, all rights reserved)
Article
Reviews psychological and psychophysiological frameworks for understanding the experience of lucid dreaming (knowing you are dreaming while the dream is ongoing). Several of the psychological approaches take an information processing view of lucid dreaming. One approach sees lucidity in sleep as a cognitive tool whereas others put more emphasis on a model of self awareness. Psychophysiological perspectives show that lucidity is a significantly more aroused REM sleep experience than nonlucid REM sleep. The EEG and lucidity work is based on the association of lucidity to meditation. This sleep experience is also viewed from the framework of spatial skills especially as implicated in vestibular system functioning. The connectionist view of neural nets is another explanatory vehicle. (PsycINFO Database Record (c) 2012 APA, all rights reserved)
Article
The current study focused on the distribution of lucid dreams in school children and young adults. The survey was conducted on a large sample of students aged 6-19 years. Questions distinguished between past and current experience with lucid dreams. Results suggest that lucid dreaming is quite pronounced in young children, its incidence rate drops at about age 16 years. Increased lucidity was found in those attending higher level compared with lower level schools. Taking methodological issues into account, we feel confident to propose a link between the natural occurrence of lucid dreaming and brain maturation.
Article
The term lucid dream designates a dream in which the dreamer is––while dreaming––aware that she/he is dreaming. Within an unselected student sample, 82% of the participants reported the occurrence of at least one lucid dream. In this sample, lucid dreaming frequency was not associated with the Big Five personality factors and, thus, theories linking lucid dreaming with introversion or well-being, that is, low neuroticism scores have not been supported. However, substantial but small correlations have been found for two openness facts (“fantasy”, “ideas”) and for dimensions which are associated with the openness to experience factor: Thin boundaries, Absorption and Imagination. Since these correlations are similar to corresponding correlations to dream recall frequency and the relationships between lucid dreaming frequency and these personality dimensions are mediated by dream recall frequency, it might be concluded that the direct relationship between lucid dreaming frequency and personality is rather small. Other variables such as meditation experience, field independence on a perceptual level, performance of the vestibular system should be included in future models explaining interindividual differences in lucid dreaming frequency. Nightmare frequency was moderately associated with lucid dreaming frequency. Although partialling out dream recall frequency reduced the magnitude of the correlation, the still significant partial correlation supports the reports of lucid dreamers that nightmares can trigger lucidity. Controlled studies investigating the effect of training the technique of lucid dreaming on nightmare frequency have not yet been carried out.
Article
Many studies have reported gender differences in nightmare frequency. In order to study this difference systematically, data from 111 independent studies have been included in the meta-analysis reported here. Overall, estimated effect sizes regarding the gender difference in nightmare frequency differed significantly from zero in three age groups of healthy persons (adolescents, young adults, and middle-aged adults), whereas for children and older persons no substantial gender difference in nightmare frequency could be demonstrated. There are several candidate variables like dream recall frequency, depression, childhood trauma, and insomnia which might explain this gender difference because these variables are related to nightmare frequency and show stable gender differences themselves. Systematic research studying the effect of these variables on the gender difference in nightmare frequency, though, is still lacking. In the present study it was found that women tend to report nightmares more often than men but this gender difference was not found in children and older persons. Starting with adolescence, the gender difference narrowed with increasing age. In addition, studies with binary coded items showed a markedly smaller effect size for the gender difference in nightmare frequency compared to the studies using multiple categories in a rating scale. How nightmares were defined did not affect the gender difference. In the analyses of all studies and also in the analysis for the children alone the data source (children vs. parents) turned out to be the most influential variable on the gender difference (reporting, age). Other results are also presented. Investigating factors explaining the gender difference in nightmare frequency might be helpful in deepening the understanding regarding nightmare etiology and possibly gender differences in other mental disorders like depression or posttraumatic stress disorder.
Article
Dreaming has fascinated and mystified humankind for ages: the bizarre and evanescent qualities of dreams have invited boundless speculation about their origin, meaning and purpose. For most of the twentieth century, scientific dream theories were mainly psychological. Since the discovery of rapid eye movement (REM) sleep, the neural underpinnings of dreaming have become increasingly well understood, and it is now possible to complement the details of these brain mechanisms with a theory of consciousness that is derived from the study of dreaming. The theory advanced here emphasizes data that suggest that REM sleep may constitute a protoconscious state, providing a virtual reality model of the world that is of functional use to the development and maintenance of waking consciousness.
Article
Synesthesia, a neurological condition affecting between 0.05%-1% of the population, is characterized by anomalous sensory perception and associated alterations in cognitive function due to interference from synesthetic percepts. A stimulus in one sensory modality triggers an automatic, consistent response in either another modality or a different aspect of the same modality. Familiality studies show evidence of a strong genetic predisposition; whereas initial pedigree analyses supported a single-gene X-linked dominant mode of inheritance with a skewed F:M ratio and a notable absence of male-to-male transmission, subsequent analyses in larger samples indicated that the mode of inheritance was likely to be more complex. Here, we report the results of a whole-genome linkage scan for auditory-visual synesthesia with 410 microsatellite markers at 9.05 cM density in 43 multiplex families (n = 196) with potential candidate regions fine-mapped at 5 cM density. Using NPL and HLOD analysis, we identified four candidate regions. Significant linkage at the genome-wide level was detected to chromosome 2q24 (HLOD = 3.025, empirical genome-wide p = 0.047). Suggestive linkage was found to chromosomes 5q33, 6p12, and 12p12. No support was found for linkage to the X chromosome; furthermore, we have identified two confirmed cases of male-to-male transmission of synesthesia. Our results demonstrate that auditory-visual synesthesia is likely to be an oligogenic disorder subject to multiple modes of inheritance and locus heterogeneity. This study comprises a significant step toward identifying the genetic substrates underlying synesthesia, with important implications for our understanding of the role of genes in human cognition and perception.
Article
We show that the neurological condition of synaesthesia--which causes fundamental differences in perception and cognition throughout a lifetime--is significantly represented within the childhood population, and that it manifests behavioural markers as young as age 6 years. Synaesthesia gives rise to a merging of cognitive and/or sensory functions (e.g. in grapheme-colour synaesthesia, reading letters triggers coloured visual photisms) and adult synaesthesia is characterized by a fixed pattern of paired associations for each synaesthete (e.g. if a is carmine red, it is always carmine red). We demonstrate that the onset of this systematicity can be detected in young grapheme-colour synaesthetes, but is an acquired trait with a protracted development. We show that grapheme-colour synaesthesia develops in a way that supersedes the cognitive growth of non-synaesthetic children (with both average and superior abilities) in a comparable paired association task. With methodology based on random sampling and behavioural tests of genuineness, we reveal the prevalence of grapheme-colour synaesthesia in children (over 170,000 grapheme-colour synaesthetes ages 0-17 in the UK, and over 930,000 in the US), the progression of the condition in longitudinal testing, and the developmental differences between synaesthetes and non-synaesthetes in matched tasks. We tested 615 children age 6-7 years from 21 primary schools in the UK. Each child was individually assessed with a behavioural test for grapheme-colour synaesthesia, which first detects differences between synaesthetes and non-synaesthetes, and then tracks the development of each group across 12 months (from ages 6/7 to 7/8 years). We show that the average UK primary school has 2-3 grapheme-colour synaesthetes at any time (and the average US primary school has five) and that synaesthetic associations (e.g. a = carmine red) develop from chaotic pairings into a system of fixed, consistent cogno-sensory responses over time. Our study represents the first assessment of synaesthesia in a randomly sampled childhood population demonstrating the real-time development of the condition. We discuss the complex profile of benefits and costs associated with synaesthesia, and our research calls for a dialogue between researchers, clinicians and educators to highlight the prevalence and characteristics of this unusual condition.
Article
In synaesthesia, ordinary stimuli elicit extraordinary experiences. For example when C., who is a digit-colour synaesthete, views black digits, each number elicits a photism - a visual experience of a specific colour. It has been proposed that synaesthetic experiences differ from imagery in their consistency, automaticity and reliance on external stimuli to induce them. Here we demonstrate that C.'s photisms are both consistent and automatic, but we find that an externally presented inducing stimulus is not necessary to trigger a photism and that simply activating the concept of a digit is sufficient.
Article
Synesthesia is a conscious experience of systematically induced sensory attributes that are not experienced by most people under comparable conditions. Recent findings from cognitive psychology, functional brain imaging and electrophysiology have shed considerable light on the nature of synesthesia and its neurocognitive underpinnings. These cognitive and physiological findings are discussed with respect to a neuroanatomical framework comprising hierarchically organized cortical sensory pathways. We advance a neurobiological theory of synesthesia that fits within this neuroanatomical framework.
Article
For individuals with synaesthesia, stimuli in one sensory modality elicit anomalous experiences in another modality. For example, the sound of a particular piano note may be 'seen' as a unique colour, or the taste of a familiar food may be 'felt' as a distinct bodily sensation. We report a study of 192 adult synaesthetes, in which we administered a structured questionnaire to determine the relative frequency and characteristics of different types of synaesthetic experience. Our data suggest the prevalence of synaesthesia in the adult population is approximately 1 in 1150 females and 1 in 7150 males. The incidence of left-handedness in our sample was within the normal range, contrary to previous claims. We did, however, find that synaesthetes are more likely to be involved in artistic pursuits, consistent with anecdotal reports. We also examined responses from a subset of 150 synaesthetes for whom letters, digits and words induce colour experiences ('lexical-colour' synaesthesia). There was a striking consistency in the colours induced by certain letters and digits in these individuals. For example, 'R' elicited red for 36% of the sample, 'Y' elicited yellow for 45%, and 'D' elicited brown for 47%. Similar trends were apparent for a group of non-synaesthetic controls who were asked to associate colours with letters and digits. Based on these findings, we suggest that the development of lexical-colour synaesthesia in many cases incorporates early learning experiences common to all individuals. Moreover, many of our synaesthetes experienced colours only for days of the week, letters or digits, suggesting that inducers that are part of a conventional sequence (e.g. Monday, Tuesday, Wednesday...; A, B, C...; 1, 2, 3...) may be particularly important in the development of synaesthetic inducer-colour pairs. We speculate that the learning of such sequences during an early critical period determines the particular pattern of lexical-colour links, and that this pattern then generalises to other words.
Article
Synesthesia is an unusual condition in which stimulation of one modality evokes sensation or experience in another modality. Although discussed in the literature well over a century ago, synesthesia slipped out of the scientific spotlight for decades because of the difficulty in verifying and quantifying private perceptual experiences. In recent years, the study of synesthesia has enjoyed a renaissance due to the introduction of tests that demonstrate the reality of the condition, its automatic and involuntary nature, and its measurable perceptual consequences. However, while several research groups now study synesthesia, there is no single protocol for comparing, contrasting and pooling synesthetic subjects across these groups. There is no standard battery of tests, no quantifiable scoring system, and no standard phrasing of questions. Additionally, the tests that exist offer no means for data comparison. To remedy this deficit we have devised the Synesthesia Battery. This unified collection of tests is freely accessible online (http://www.synesthete.org). It consists of a questionnaire and several online software programs, and test results are immediately available for use by synesthetes and invited researchers. Performance on the tests is quantified with a standard scoring system. We introduce several novel tests here, and offer the software for running the tests. By presenting standardized procedures for testing and comparing subjects, this endeavor hopes to speed scientific progress in synesthesia research.