Lucid dream

In the psychology subfield of oneirology, a lucid dream is a type of dream wherein the dreamer realizes that they are dreaming during their dream. The capacity to have and sustain lucid dreams is a trainable cognitive skill. During a lucid dream, the dreamer may gain some amount of volitional control over the dream characters, narrative, or environment, although this control of dream content is not the salient feature of lucid dreaming. An important distinction is that lucid dreaming is a distinct type of dream from other types of dreams such as prelucid dreams and vivid dreams, although prelucid dreams are a precursor to lucid dreams, and lucid dreams are often accompanied with enhanced dream vividness. Lucid dreams are also a distinct state from other lucid boundary sleep states such as lucid hypnagogia or lucid hypnopompia.
In formal psychology, lucid dreaming has been studied and reported for many years. Prominent figures from ancient to modern times have been fascinated by lucid dreams and have sought ways to better understand their causes and purpose. Many different theories have emerged as a result of scientific research on the subject. Further developments in psychological research have pointed to ways in which this form of dreaming may be utilized as a therapeutic technique.
The term lucid dream was coined by Dutch author and psychiatrist Frederik van Eeden in his 1913 article A Study of Dreams, though descriptions of dreamers being aware that they are dreaming predate the article. Psychologist Stephen LaBerge is widely considered the progenitor and leading pioneer of modern lucid dreaming research. He is the founder of the Lucidity Institute at Stanford University.

Definition

laid the epistemological basis for the research of lucid dreams, proposing seven different conditions of clarity that a dream must fulfill to be defined as a lucid dream:

Awareness of the dream state
Awareness of the capacity to make decisions
Awareness of memory functions
Awareness of self
Awareness of the dream environment
Awareness of the meaning of the dream
Awareness of concentration and focus

Later, in 1992, a study by Deirdre Barrett examined whether lucid dreams contained four "corollaries" of lucidity:

The dreamer is aware that they are dreaming
They are aware that actions will not carry over after waking
Physical laws need not apply in the dream
The dreamer has a clear memory of the waking world

Barrett found that less than a quarter of lucidity accounts exhibited all four.
Subsequently, Stephen LaBerge studied the prevalence among lucid dreams of the ability to control the dream scenario, and found that while dream control and dream awareness are correlated, neither requires the other. LaBerge found dreams that exhibit one clearly without the capacity for the other. He also found dreams where, although the dreamer is lucid and aware they could exercise control, they choose simply to observe.

History

Eastern

The practice of lucid dreaming is central to both the ancient Indian Hindu practice of Yoga nidra and the Tibetan Buddhist practice of dream Yoga. The cultivation of such awareness was a common practice among early Buddhists.

Western

Early references to the phenomenon are also found in ancient Greek writing. For example, the philosopher Aristotle wrote: "often when one is asleep, there is something in consciousness which declares that what then presents itself is but a dream." Meanwhile, the physician Galen of Pergamon used lucid dreams as a form of therapy. In addition, a letter written by Saint Augustine of Hippo in AD 415 tells the story of a dreamer, Doctor Gennadius, and refers to lucid dreaming.
Philosopher and physician Sir Thomas Browne was fascinated by dreams and described his own ability to lucid dream in his Religio Medici, stating: "...yet in one dream I can compose a whole Comedy, behold the action, apprehend the jests and laugh my self awake at the conceits thereof."
Samuel Pepys, in his diary entry for 15 August 1665, records a dream, stating: "I had my Lady Castlemayne in my arms and was admitted to use all the dalliance I desired with her, and then dreamt that this could not be awake, but that it was only a dream."
In 1867, the French sinologist Marie-Jean-Léon, Marquis d'Hervey de Saint Denys anonymously published Les Rêves et Les Moyens de Les Diriger; Observations Pratiques, in which he describes his own experiences of lucid dreaming, and proposes that it is possible for anyone to learn to dream consciously.
File:EedenSaintDenys.jpg|thumb|upright=1.3|Frederik van Eeden and Marquis d'Hervey de Saint Denys, early researchers of lucid dreaming
In 1913, Dutch psychiatrist and writer Frederik van Eeden coined the term "lucid dream" in an article entitled "A Study of Dreams".
Some have suggested that the term is a misnomer because Van Eeden was referring to a phenomenon more specific than a lucid dream. Van Eeden intended the term lucid to denote "having insight", as in the phrase a lucid interval applied to someone in temporary remission from a psychosis, rather than as a reference to the perceptual quality of the experience, which may or may not be clear and vivid.

Skill mastery

Clinical psychologist, Kristen LaMarca outlined four stages towards mastering the skill of using lucid dreaming:

Stage	Title	Description	Rarity
1	Beginner		Common
2	Experienced		Less common
3	Proficient		Uncommon
4	Expert		Extremely rare

Progression along the skill levels is akin to a maturity in the development of the practitioner's discipline, methodology and application.

Cognitive science

In 1968, Celia Green analyzed the main characteristics of such dreams, reviewing previously published literature on the subject and incorporating new data from participants of her own. She concluded that lucid dreams were a category of experience quite distinct from ordinary dreams and said they were associated with rapid eye movement sleep. Green was also the first to link lucid dreams to the phenomenon of false awakenings, which has since been corroborated by more recent studies.
In 1973, the National Institute of Mental Health reported that researchers at the University of California, San Francisco, were able to train sleeping subjects to recognize they were in REM dreaming and indicate this by pressing micro switches on their thumbs. Using tones and mild shocks as cues, the experiments showed that the subjects were able to signal knowledge of their various sleep stages, including dreaming.
In 1975, Dr. Keith Hearne had the idea to exploit the nature of rapid eye movements to allow a dreamer to send a message directly from dreams to the waking world. Working with an experienced lucid dreamer, he eventually succeeded in recording a pre-defined set of eye movements signaled from within Worsley's lucid dream. This occurred at around 8 am on the morning of April 12, 1975. Hearne's EOG experiment was formally recognized through publication in the journal for The Society for Psychical Research. Lucid dreaming was subsequently researched by asking dreamers to perform pre-determined physical responses while experiencing a dream, including eye movement signals.
In 1980, Stephen LaBerge at Stanford University developed such techniques as part of his doctoral dissertation. In 1985, LaBerge performed a pilot study that showed that time perception while counting during a lucid dream is about the same as during waking life. Lucid dreamers counted out ten seconds while dreaming, signaling the start and the end of the count with a pre-arranged eye signal measured with electrooculogram recording. LaBerge's results were confirmed by German researchers D. Erlacher and M. Schredl in 2004.
In a further study by Stephen LaBerge, four subjects were compared, either singing or counting while dreaming. LaBerge found that the right hemisphere was more active during singing and the left hemisphere was more active during counting.
Neuroscientist J. Allan Hobson has hypothesized what might be occurring in the brain while lucid. The first step to lucid dreaming is recognizing that one is dreaming. This recognition might occur in the dorsolateral prefrontal cortex, which is one of the few areas deactivated during REM sleep and where working memory occurs. Once this area is activated and the recognition of dreaming occurs, the dreamer must be cautious to let the dream continue, but be conscious enough to remember that it is a dream. While maintaining this balance, the amygdala and parahippocampal cortex might be less intensely activated. To continue the intensity of the dream hallucinations, it is expected the pons and the parieto-occipital junction stay active.
Using electroencephalography and other polysomnographical measurements, LaBerge and others have shown that lucid dreams begin in the rapid eye movement stage of sleep. LaBerge also proposes that there are higher amounts of beta-1 frequency band brain wave activity experienced by lucid dreamers, hence there is an increased amount of activity in the parietal lobes making lucid dreaming a conscious process.
Paul Tholey, a German Gestalt psychologist and a professor of psychology and sports science, originally studied dreams in order to resolve the question of whether one dreams in colour or black and white. In his phenomenological research, he outlined an epistemological frame using critical realism. Tholey instructed his subjects to continuously suspect waking life to be a dream, in order that such a habit would manifest itself during dreams. He called this technique for inducing lucid dreams the Reflexionstechnik. Subjects learned to have such lucid dreams; they observed their dream content and reported it soon after awakening. Tholey could examine the cognitive abilities of dream figures. Nine trained lucid dreamers were directed to set other dream figures arithmetic and verbal tasks during lucid dreaming. Dream figures who agreed to perform the tasks proved more successful in verbal than in arithmetic tasks. Tholey discussed his scientific results with Stephen LaBerge, who has a similar approach.
A study was conducted by Stephen LaBerge and other scientists to see if it were possible to attain the ability to lucid dream through a drug. In 2018, galantamine was given to 121 patients in a double-blind, placebo-controlled trial, the only one of its kind. Some participants found as much as a 42 percent increase in their ability to lucid dream, compared to self-reports from the past six months, and ten people experienced a lucid dream for the first time. It is theorized that galantamine allows acetylcholine to build up, leading to greater recollection and awareness during dreaming.