In lucid dreams, the dreamer
realizes they are dreaming even as they remain asleep. What is the science
behind this intriguing consciousness phenomenon? This special feature looks at
the current research.
Can scientists explain lucid dreams? Read this special feature to find out what researchers have learned so far.
Typically,
when we dream, we are not aware that we are dreaming, and the most unlikely
events, characters, and environments seem real to us.
But
now and again, some of us realize that we are in a dream as we are dreaming.
This phenomenon is called "lucid dreaming," and it has stirred the
interest of researchers and the public alike.
Learning
to control aspects of your dreams can be a great way of exploring activities
you could never do in real life, facing and overcoming fears, and learning more
about your subconscious.
In
a previous
special feature on Medical
News Today, we have explained what lucid dreams are, talked about
some techniques you can apply to achieve them, and looked at whether there are
any risks associated with this practice.
In
this article, we take that discussion a step further, looking at some of the
science behind lucid dreaming.
So
if you are interested in finding out how common lucid dreams are, who is more
prone to having them and why, and what happens in the brain during a lucid
dream, read on.
How common are lucid dreams?
It
remains unclear how many people experience lucid dreams, but researchers have
provided rough estimates based on personal reports they accessed through their
studies.
Around 50% of people have had a lucid dream at least once in their lives.
A 2017 study published in the journal Imagination, Cognition and
Personality: Consciousness in Theory, Research, and Clinical Practice referred
to estimates suggesting that in a representative population, 51% of the
individuals had experienced a lucid dream at least once in their lives, and
about 20% experienced lucid dreams at least once a month.
The
same study notes that people are more likely to experience spontaneous lucid
dreams in their childhood, starting at about 3 and 4 years old. However, the
likelihood of lucid dreaming begins to decline in early adolescence.
"After
the age of 25, spontaneous onset of lucid dreaming appears to be very
infrequent," the study authors write.
The
researchers — who hail from the Universities of Mannheim and Heidelberg, both
in Germany — investigated whether or not personality traits could help predict
a person's likelihood of experiencing lucid dreams.
The
study found that openness to an experience correlates positively with lucid
dreaming frequency. However, agreeableness —a personality trait that often
indicates a person's level of friendliness and tact in interpersonal
relationships — does not.
The
study also identified that neuroticism —
a personality factor that often presents as strong moods, anxiety,
and depression — had
associations with a higher frequency of lucid dreams.
Lucid dreams and sleep disturbances
Denholm Aspy, Ph.D., who
researches lucid dreaming, spoke to MNT and
suggested that certain neurophysiological or neurochemical factors may also
render a person more likely to experience spontaneous lucid dreams.
Some studies have found a correlation between lucid dreaming and sleep paralysis.
More
often than not, lucid dreaming occurs during the REM (rapid eye movement) phase of sleep,
which is also when many regular dreams occur. It is possible that neurochemical
peculiarities may play a role in "switching on" parts of our
consciousness when they would generally be "switched off."
"I'm
speculating a little bit here, but some people might just tend to produce more
of the neurotransmitters that pause REM sleep, typically acetylcholine,"
Aspy told us.
"You might have some random variation in
neurology or neurochemistry [...] I know that people with narcolepsy tend to
have a lot more lucid dreams than the average person, and they're having a lot
of sleep disturbances," he went on to say.
Some
anecdotal experiences, as well as some studies, suggest that lucid dreaming may
have more in common with the experience of sleep
paralysis than that of regular dreaming.
In sleep
paralysis, the mind awakens to a certain degree, while the body
remains asleep and unable to move. When that happens, individuals usually
experience very realistic hallucinations, as though the content of a dream had
"leaked" into the real world.
For
instance, a 2017 study — featured in the Journal of Sleep Research —
found a significant positive correlation between sleep paralysis and lucid
dreaming frequency in a cohort of 1,928 adult participants.
"It
is [...] likely that these sleep experiences are underlined by similar
neurophysiology," the study authors write.
They
also note that "[d]issociative experience was the only common predictor of
both sleep paralysis and lucid dreaming frequency, indicating that individuals
who experience both unusual sleep experiences also experience greater dissociative
experiences in daily life."
The role of diet and meditation
People who meditate may find it easier to have lucid dreams.
Besides
neurochemical and neurophysiological factors, Aspy told us, there may also be
other unexpected contributors to whether or not a person is likely to
experience lucid dreams. One factor, he explained, could simply be nutrition.
"People
that are low in certain vitamins [...] they
tend to have poor dream recall and not have lucid dreams at all," Aspy
said, "whereas, for example, in my study that I published [in 2017], I
found that giving people vitamin B-6 supplements caused them to remember more
of their dreams, and that could be useful for having lucid dreams as
well."
In that study —
which he previously covered on MNT —
Aspy and colleagues found that individuals who took 240 milligrams (mg) of
vitamin B-6 for four nights before going to bed found it much easier to
remember their dreams when they woke up.
"[G]eneral
dream recall is the most important predictor of lucid dreams," Aspy
told MNT. This means that
certain changes to the diet might make it more likely that people not only
recall their regular dreams when they wake up but also that they can turn regular
dreams into lucid dreams more easily.
Another
factor that may play a role in a person's likelihood to experience lucid dreams
is meditation. A 2015 study found that people who had practiced
meditation for a long time tended to have more lucid dreams.
This,
the researchers explain, makes sense because "[a]ttention to the present
state of consciousness in wakefulness and contemplating whether the current
experience might be a dream is one of the core techniques [...] in modern lucid
dream practice."
What happens in the brain?
But
what happens in the brain when a person experiences a lucid dream? "Lucid
dreaming is a hybrid state of consciousness with features of both waking and
dreaming," write Julian Mutz and Amir-Homayoun Javadi in a review they
published in Neuroscience of Consciousness in 2017.
Some lucid dreams are actually lucid nightmares, and researchers are still unsure why those occur.
That
makes this sleep experience particularly intriguing, all the more so
considering that scientists are still unclear about all the brain mechanisms
related to regular dreaming.
In
their review, Mutz and Javadi looked at previous studies concerning brain
activity during sleep and, more specifically, during periods of regular
dreaming versus lucid dreaming.
The
two researchers found that during lucid dreaming, there is increased activity
in the dorsolateral prefrontal cortex, the bilateral frontopolar prefrontal
cortex, the precuneus, the inferior parietal lobules, and the supramarginal
gyrus.
These are all brain areas related to higher
cognitive functions, including attention, working memory, planning, and
self-consciousness.
By
looking at the research on lucid dreaming and states of consciousness, the
researchers also found that during a lucid dream, "levels of
self-determination (i.e., the subjective experience of acting freely according
to one's will)" were similar to those that people experienced during
states of wakefulness. During regular dreams, however, self-determination was
significantly reduced.
Mutz
and Javadi also note that by further studying lucid dreaming, scientists could
learn more about different types of consciousness, which are less easy to
separate and study at other times.
Tadas
Stumbrys, Ph.D. — a researcher from Vilnius University in Lithuania, who
specializes in the science of dreams — notes that
perfecting the art of lucid dreaming is tempting for many people, who often use
it for "wish fulfillment, such as flying or engaging in sex."
While
it is certainly possible to become better at lucid dreaming, lucid dreamers can
only control limited aspects of their dream at once. "I've never heard of
anyone who can control everything about a lucid dream at the same time,"
Aspy told us.
Many
features of lucid dreaming remain a mystery, such as details about the brain
mechanisms behind it. Another unknown is why lucid dreams can sometimes turn
ominous — about 7% of them are, surprisingly, lucid nightmares, according to
Stumbrys.
These
are avenues for future research, which is yet to understand what lucid dreams
can achieve for the dreamer, and where they fit on the map of sleep
experiences.
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