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Dreaming and Lucidity in Synesthesia

March 2022
Dreaming 32(2)

DOI:10.1037/drm0000190

Authors:

Christopher Sinke

Hannover Medical School

Markus Zedler

Hannover Medical School

Show all 6 authorsHide

Synesthesia is a phenomenon in which the stimulation of 1 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, synesthetes 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 synesthetes’ unusual perception is reflected in the dream state. Little is known about synesthetes’ dreaming behavior. 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–color synesthetes; N = 32 nonsynesthetes) indicated their dream experiences and completed the Lucidity and Consciousness in Dreams scale. Synesthetes reported lucid dream experiences significantly more often than nonsynesthetes. Qualitative differences were not found between both groups’ lucid dreamers. The 2 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 Lucidity and Consciousness in Dreams scale. The results are discussed regarding the relevance of lucidity in synesthesia within the context of consciousness research.

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Dreaming and Lucidity in Synesthesia

Vlada Khallieva

, Christopher Sinke

, Markus Zedler

, Hans Worthmann

Stefan Bleich

, and Gregor R. Szycik

Clinic for Psychiatry, Social Psychiatry and Psychotherapy, Hannover Medical

School

Department of Neurology, Hannover Medical School

Synesthesia is a phenomenon in which the stimulation of 1 sensory modality auto-

matically and consistently over time evokes a sensation in the same or a different mo-

dality in an idiosyncratic manner. In addition to pure sensory coupling, synesthetes 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 synesthetes’unusual perception is reﬂected in the dream

state. Little is known about synesthetes’dreaming behavior. 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 connec-

tion to one’s waking reality, wake up in a targeted manner, and control dream actions.

Through self-report measures, participants (N = 31 grapheme–color synesthetes; N =

32 nonsynesthetes) indicated their dream experiences and completed the Lucidity and

Consciousness in Dreams scale. Synesthetes reported lucid dream experiences signiﬁ-

cantly more often than nonsynesthetes. Qualitative differences were not found between

both groups’lucid dreamers. The 2 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 Lucidity and Consciousness in

Dreams scale. The results are discussed regarding the relevance of lucidity in synesthe-

sia within the context of consciousness research.

Keywords: synesthesia, dreams, lucid dreaming, consciousness

Synesthesia refers to an unusual experience in which the stimulation of one sen-

sory modality involuntarily triggers a sensation in another (Grossenbacher & Lovelace,

2001). Characteristic features of the individual networking of sensory impressions are

automaticity and consistency over time (Dixon et al., 2000;Rich et al., 2005). The most

This article was published Online First March 10, 2022.

The authors have no conﬂict of interest to disclose.

Correspondence concerning this article should be addressed to Vlada Khallieva, Clinic for Psychiatry,

Social Psychiatry and Psychotherapy, Hannover Medical School, Podbielskistraße 162, 30177 Hannover,

Germany. Email: vlada.khallieva@stud.mh-hannover.de

206

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ISSN: 1053-0797 https://doi.org/10.1037/drm0000190

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Lucid dreaming refers to the phenomenon of becoming aware of the fact that one is dreaming during ongoing sleep. Despite having been physiologically validated for decades, the neurobiology of lucid dreaming is still incompletely characterized. Here we review the neuroscientific literature on lucid dreaming, including electroencephalographic, neuroimaging, brain lesion, pharmacological and brain stimulation studies. Electroencephalographic studies of lucid dreaming are mostly underpowered and show mixed results. Neuroimaging data is scant but preliminary results suggest that prefrontal and parietal regions are involved in lucid dreaming. A focus of research is also to develop methods to induce lucid dreams. Combining training in mental set with cholinergic stimulation has shown promising results, while it remains unclear whether electrical brain stimulation could be used to induce lucid dreams. Finally, we discuss strategies to measure lucid dreaming, including best-practice procedures for the sleep laboratory. Lucid dreaming has clinical and scientific applications, and shows emerging potential as a methodology in the cognitive neuroscience of consciousness. Further research with larger sample sizes and refined methodology is needed.

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