500 lines
25 KiB
Plaintext
500 lines
25 KiB
Plaintext
LUCID DREAMING: AWAKE IN YOUR SLEEP?
|
|
|
|
By Susan Blackmore
|
|
|
|
From Skeptical Inquirer, Vol. 15 Summer 1991
|
|
pages 362-370
|
|
|
|
What could it mean to be conscious in your dreams? For most of us,
|
|
dreaming is something quite separate from normal life. When we
|
|
wake up from being chased by a ferocious tiger, or seduced by a
|
|
devastatingly good-looking Nobel Prize winner we realize with
|
|
relief or disappointment that "it was only a dream."
|
|
|
|
Yet there are some dreams that are not like that. Lucid dreams are
|
|
dreams in which you know at the time that you are dreaming. That
|
|
they are different from ordinary dreams is obvious as soon as you
|
|
have one. The experience is something like waking up in your
|
|
dreams. It is as though you "come to" and find you are dreaming.
|
|
|
|
Lucid dreams used to be a topic within psychical research and
|
|
parapsychology. Perhaps their incomprehensibility made them good
|
|
candidates for being thought paranormal. More recently, however,
|
|
they have begun to appear in psychology journals and have dropped
|
|
out of parapsychology - a good example of how the field of
|
|
parapsychology shrinks when any of its subject matter is actually
|
|
explained.
|
|
|
|
Lucidity has also become something of a New Age fad. There are
|
|
machines and gadgets you can buy and special clubs you can join to
|
|
learn how to induce lucid dreams. But this commercialization
|
|
should not let us lose sight of the very real fascination of lucid
|
|
dreaming. It forces us to ask questions about the nature of
|
|
consciousness, deliberate control over our actions, and the nature
|
|
of imaginary worlds.
|
|
|
|
A Real Dream or Not?
|
|
|
|
The term lucid dreaming was coined by the Dutch psychiatrist
|
|
Frederik van Eeden in 1913. It is something of a misnomer since it
|
|
means something quite different from just clear or vivid dreaming.
|
|
Nevertheless we are certainly stuck with it. Van Eeden explained
|
|
that in this sort of dream "the re-integration of the psychic
|
|
functions is so complete that the sleeper reaches a state of
|
|
perfect awareness and is able to direct his attention, and to
|
|
attempt different acts of free volition. Yet the sleep, as I am
|
|
able confidently to state, is undisturbed, deep, and refreshing."
|
|
|
|
This implied that there could be consciousness during sleep, a
|
|
claim many psychologists denied for more than 50 years. Orthodox
|
|
sleep researchers argued that lucid dreams could not possibly be
|
|
real dreams. If the accounts were valid, then the experiences must
|
|
have occurred during brief moments of wakefulness or in the
|
|
transition between waking and sleeping, not in the kind of deep
|
|
sleep in which rapid eye movements (REMs) and ordinary dreams
|
|
usually occur. In other words, they could not really be dreams at
|
|
all.
|
|
|
|
This presented a challenge to lucid dreamers who wanted to
|
|
convince people that they really were awake in their dreams. But
|
|
of course when you are deep asleep and dreaming you cannot shout,
|
|
"Hey! Listen to me. I'm dreaming right now." All the muscles of
|
|
the body are paralyzed.
|
|
|
|
It was Keith Hearne (1978), of the University of Hull, who first
|
|
exploited the fact that not all the muscles are paralyzed. In REM
|
|
sleep the eyes move. So perhaps a lucid dreamer could signal by
|
|
moving the eyes in a predetermined pattern. Just over ten years
|
|
ago, lucid dreamer Alan Worsley first managed this is in Hearne's
|
|
laboratory. He decided to move his eyes left and right eight times
|
|
in succession whenever he became lucid. Using a polygraph, Hearne
|
|
could watch the eye movements for sign of the special signal. He
|
|
found it in the midst of REM sleep. So lucid dreams are real
|
|
dreams and do occur during REM sleep.
|
|
|
|
Further research showed that Worsley's lucid dreams most often
|
|
occurred in the early morning, around 6:30 A.M., nearly half an
|
|
hour into a REM period and toward the end of a burst of rapid eye
|
|
movements. They usually lasted for two to five minutes. Later
|
|
research showed that they occur at times of particularly high
|
|
arousal during REM sleep (Hearne 1978).
|
|
|
|
It is sometimes said that discoveries in science happen when the
|
|
time is right for them. It was one of those odd things that at
|
|
just the same time, but unbeknown to Hearne, Stephen LaBerge, at
|
|
Stanford University in California, was trying the same experiment.
|
|
He too succeeded, but resistance to the idea was very strong. In
|
|
1980, both Science and Nature rejected his first paper on the
|
|
discovery (LaBerge 1985). It was only later that it became clear
|
|
what an important step this had been.
|
|
|
|
An Identifiable State?
|
|
|
|
It would be especially interesting if lucid dreams were associated
|
|
with a unique physiological state. In fact this has not been
|
|
found, although this is not very surprising since the same is true
|
|
of other altered states, such as out-of-body experiences and
|
|
trances of various kinds. However, lucid dreams do tend to occur
|
|
in periods of higher cortical arousal. Perhaps a certain threshold
|
|
of arousal has to be reached before awareness can be sustained.
|
|
|
|
The beginning of lucidity (marked by eye signals, of course) is
|
|
associated with pauses in breathing, brief changes in heart rate,
|
|
and skin response changes, but there is no unique combination that
|
|
allows the lucidity to be identified by an observer.
|
|
|
|
In terms of the dream itself, there are several features that seem
|
|
to provoke lucidity. Sometimes heightened anxiety or stress
|
|
precedes it. More often there is a kind of intellectual
|
|
recognition that something "dreamlike" or incongruous is going on
|
|
(Fox 1962; Green 1968; LaBerge 1985).
|
|
|
|
It is common to wake from an ordinary dream and wonder, "How on
|
|
earth could I have been fooled into thinking that I was really
|
|
doing push-ups on a blue beach?" A little more awareness is shown
|
|
when we realize this in the dream. If you ask yourself, "Could
|
|
this be a dream?" and answer "No" (or don't answer at all), this
|
|
is called a pre-lucid dream. Finally, if you answer "Yes", it
|
|
becomes a fully lucid dream.
|
|
|
|
It could be that once there is sufficient cortical arousal it is
|
|
possible to apply a bit of critical thought; to remember enough
|
|
about how the world ought to be to recognize the dream world as
|
|
ridiculous, or perhaps to remember enough about oneself to know
|
|
that these events can't be continuous with normal waking life.
|
|
However, tempting as it is to conclude that the critical insight
|
|
produces the lucidity, we have only an apparent correlation and
|
|
cannot deduce cause and effect from it.
|
|
|
|
Becoming a Lucid Dreamer
|
|
|
|
Surveys have show that about 50 percent of people (and in some
|
|
cases more) have had at least one lucid dream in their lives.
|
|
(see, for example, Blackmore 1982; Gackenbach and LaBerge 1988;
|
|
Green 1968.) Of course surveys are unreliable in that many people
|
|
may not understand the question. In particular, if you have never
|
|
had a lucid dream, it is easy to misunderstand what is meant by
|
|
the term. So overestimates might be expected. Beyond this, it
|
|
does not seem that surveys can find out much. There are no very
|
|
consistent differences between lucid dreamers and others in terms
|
|
of age, sex, education, and so on (Green 1968; Gackenbach and
|
|
LaBerge 1988).
|
|
|
|
For many people, having lucid dream is fun, and they want to learn
|
|
how to have more or to induce them at will. One finding from early
|
|
experimental work was that high levels of physical (and emotional)
|
|
activity during the day tend to precede lucidity at night. Waking
|
|
during the night and carrying out some kind of activity before
|
|
falling asleep again can also encourage a lucid dream during the
|
|
next REM period and is the basis of some induction techniques.
|
|
|
|
Many methods have been developed (Gackenbach and Bosveld 1989;
|
|
Tart 1988; Price and Cohen 1988). They roughly fall into three
|
|
categories.
|
|
|
|
One of the best known is LaBerge's MILD (Mnemonic Induction of
|
|
Lucid Dreaming). This is done on waking in the early morning from
|
|
a dream. You should wake up fully, engage in some activity like
|
|
reading or walking about, and then lie down to go to sleep again.
|
|
Then you must imagine yourself asleep and dreaming, rehearse the
|
|
dream from which you woke, and remind yourself, "Next time I dream
|
|
this I want to remember I'm dreaming."
|
|
|
|
A second approach involves constantly reminding yourself to become
|
|
lucid throughout the day rather than the night. This is based on
|
|
the idea that we spend most of our time in a kind of waking daze.
|
|
If we could be more lucid in waking life, perhaps we could be more
|
|
lucid while dreaming. German psychologist Paul Tholey suggests
|
|
asking yourself many times every day, "Am I dreaming or not?" This
|
|
sound easy but is not. It takes a lot of determination and
|
|
persistence not to forget all about it. For those who do forget,
|
|
French researcher Clerc suggests writing a large "C" on your hand
|
|
(for "conscious") to remind you (Tholey 1983; Gackenbach and
|
|
Bosveld 1989).
|
|
|
|
This kind of method is similar to the age-old technique for
|
|
increasing awareness by meditation and mindfulness. Advanced
|
|
practitioners of meditation claim to maintain awareness through a
|
|
large proportion of their sleep. TM is often claimed to lead to
|
|
sleep awareness. So perhaps it is not surprising that some recent
|
|
research finds association between meditation and increased
|
|
lucidity (Gackenbach and Bosveld 1989).
|
|
|
|
The third and final approach requires a variety of gadgets. The
|
|
idea is to use some sort of external signal to remind people,
|
|
while they are actually in REM sleep, that they are dreaming.
|
|
Hearne first tried spraying water onto sleepers' faces or hands
|
|
but found it too unreliable. This sometimes caused them to
|
|
incorporate water imagery into their dreams, but they rarely
|
|
became lucid. He eventually decided to use a mild electrical shock
|
|
to the wrist. His "dream machine" detects changes in breathing
|
|
rate (which accompany the onset of REM) and then automatically
|
|
delivers a shock to the wrist (Hearne 1990).
|
|
|
|
Meanwhile, in California, LaBerge was rejecting taped voices and
|
|
vibrations and working instead with flashing lights. The original
|
|
version was laboratory based and used a personal computer to
|
|
detect the eye movements of REM sleep and to turn on flashing
|
|
lights whenever the REMs reached a certain level. Eventually,
|
|
however, all the circuitry was incorporated into a pair of
|
|
goggles. The idea is to put the goggles on at night, and the
|
|
lights will flash only when you are asleep and dreaming. The user
|
|
can even control the level of eye movements at which the lights
|
|
begin to flash.
|
|
|
|
The newest version has a chip incorporated into the goggles. This
|
|
will not only control the lights but will store data on
|
|
eye-movement density during the night and when and for how long
|
|
the lights were flashing, making fine tuning possible. At the
|
|
moment, the first users have to join in workshops at LaBerge's
|
|
Lucidity Institute and learn how to adjust the settings, but
|
|
within a few months he hopes the whole process will be fully
|
|
automated. (See LaBerge's magazine, DreamLight.)
|
|
|
|
LaBerge tested the effectiveness of the Dream Light on 44 subjects
|
|
who came into the laboratory, most for just one night. Fifty-five
|
|
percent had at least one lucid dream this way. The results
|
|
suggested that this method is about as succesful as MILD, but
|
|
using the two together is the most effective (LaBerge 1985).
|
|
|
|
Lucid Dreams as an Experimental Tool
|
|
|
|
There are a few people who can have lucid dreams at will. And the
|
|
increase in induction techniques has provided many more subjects
|
|
who have them frequently. This has opened the way to using lucid
|
|
dreams to answer some of the most interesting questions about
|
|
sleep and dreaming.
|
|
|
|
How long do dreams take? In the last century, Alfred Maury had a
|
|
long and complicated dream that led to his being beheaded by a
|
|
guillotine. He woke up terrified, and found that the headboard of
|
|
his bed had fallen on his neck. From this, the story goes, he
|
|
concluded that the whole dream had been created in the moment of
|
|
awakening.
|
|
|
|
This idea seems to have got into popular folklore but was very
|
|
hard to test. Researchers woke dreamers at various stages of
|
|
their REM period and found that those who had been longer in REM
|
|
claimed longer dreams. However, accurate timing became possible
|
|
only when lucid dreamers could send "markers" from the dream
|
|
state.
|
|
|
|
LaBerge asked his subjects to signal when they became lucid and
|
|
then count a ten-second period and signal again. Their average
|
|
interval was 13 seconds, the same as they gave when awake. Lucid
|
|
dreamers, like Alan Worsley, have also been able to give accurate
|
|
estimates of the length of whole dreams or dream segments
|
|
(Schatzman, Worsley, and Fenwick 1988).
|
|
|
|
Dream Actions
|
|
|
|
As we watch sleeping animals it is often tempting to conclude that
|
|
they are moving their eyes in response to watching a dream, or
|
|
twitching their legs as they dream of chasing prey. But do
|
|
physical movements actually relate to the dream events?
|
|
|
|
Early sleep researchers occassionally reported examples like a
|
|
long series of left-right eye movements when a dreamer had been
|
|
dreaming of watching a ping-pong game, but they could do no more
|
|
than wait until the right sort of dream came along.
|
|
|
|
Lucid dreaming made proper experimentation possible, for the
|
|
subjects could be asked to perform a whole range of tasks in their
|
|
dreams. In one experiment with researchers Morton Schatzman and
|
|
Peter Fenwick, in London, Worsley planned to draw large triangles
|
|
and to signal with flicks of his eyes every time he did so. While
|
|
he dreamed, the electromyogram, recording small muscle movements,
|
|
showed not only the eye signals but spikes of electrical activity
|
|
in the right forearm just afterward. This showed that the
|
|
preplanned actions in the dream produced corresponding muscle
|
|
movements (Schatzman, Worsley, and Fenwick 1988).
|
|
|
|
Further experiments, with Worsley kicking dream objects, writing
|
|
with umbrellas, and snapping his fingers, all confirmed that the
|
|
muscles of the body show small movements corresponding to the
|
|
body's actions in the dream. The question about eye movements was
|
|
also answered. The eyes do track dream objects. Worsley could
|
|
even produce slow scanning movements, which are very difficult to
|
|
produce in the absence of a "real" stimulus (Schatzman, Worsley,
|
|
and Fenwick 1988).
|
|
|
|
LaBerge was especially interested in breathing during dreams.
|
|
This stemmed from his experiences at age five when he had dreamed
|
|
of being an undersea pirate who could stay under water for very
|
|
long periods without drowning. Thirty years later he wanted to
|
|
find out whether dreamers holding their breath in dreams do so
|
|
physically as well. The answer was yes. He and other lucid
|
|
dreamers were able to signal from the dream and then hold their
|
|
breath. They could also breathe rapidly in their dreams, as
|
|
revealed on the monitors. Studying breathing during dreamed
|
|
speech, he found that the person begins to breathe out at the
|
|
start of an utterance just as in real speech (LaBerge and Dement
|
|
1982a).
|
|
|
|
Hemispheric Differences
|
|
|
|
It is known that the left and right hemispheres are activated
|
|
differently during different kinds of tasks. For example, singing
|
|
uses the right hemisphere more, while counting and other, more
|
|
analytical tasks use the left hemisphere more. By using lucid
|
|
dreams, LaBerge was able to find out whether the same is true in
|
|
dreaming.
|
|
|
|
In one dream he found himself flying over a field. (Flying is
|
|
commonly associated with lucid dreaming.) He signaled with his
|
|
eyes and began to sing "Row, row, row your boat...." He then made
|
|
another signal and counted slowly to ten before signaling again.
|
|
The brainwave records showed just the same patterns of activation
|
|
that you would expect if he had done these tasks while awake
|
|
(LaBerge and Dement 1982b).
|
|
|
|
Dream Sex
|
|
|
|
Although it is not often asked experimentally, I am sure plenty of
|
|
people have wondered what is happening in their bodies while they
|
|
have their most erotic dreams.
|
|
|
|
LaBerge tested a woman who could dream lucidly at will and could
|
|
direct her dreams to create the sexual experiences she wanted.
|
|
(What a skill!) Using appropriate physiological recording, he was
|
|
able to show that her dream orgasms were matched by true orgasms
|
|
(LaBerge, Greenleaf, and Kedzierski 1983).
|
|
|
|
Experiments like these show that there is a close correspondence
|
|
between actions of the dreamer and, if not real movements, at
|
|
least eletrical responses. This puts lucid dreaming somewhere
|
|
between real actions, in which muscles work to move the body, and
|
|
waking imagery, in which they are rarely involved at all. So what
|
|
exactly is the status of the dream world?
|
|
|
|
The Nature of the Dream World
|
|
|
|
It is tempting to think that the real world and the world of
|
|
dreams are totally separate. Some of the experiments already
|
|
mentioned show that there is no absolute dividing line. There are
|
|
also plenty of stories that show the penetrability of the
|
|
boundary.
|
|
|
|
Alan Worsley describes one experiment in which his task was to
|
|
give himself a prearranged number of small electric shocks by
|
|
means of a machine measuring his eye movements. He went to sleep
|
|
and began dreaming that it was raining and he was in a sleeping
|
|
bag by a fence with gate in it. He began to wonder whether he was
|
|
dreaming and thought it would be cheating to activate the shocks
|
|
if he was awake. Then, while making the signals, he worried about
|
|
the machine, for it was out there with him in the rain and might
|
|
get wet (Schatzman, Worsley, and Fenwick 1988).
|
|
|
|
This kind of interference is amusing, but there are dreams of
|
|
confusion that are not. The most common and distinct are called
|
|
false awakenings. You dream of waking up but in fact, of course,
|
|
are still asleep. Van Eeden (1913) called these "wrong waking up"
|
|
and described them as "demoniacal, uncanny, and very vivid and
|
|
bright, with ... a strong diabolical light." The French zoologist
|
|
Yves Delage, writing in 1919, described how he had heard a knock
|
|
at his door and a friend calling for his help. He jumped out of
|
|
bed, went to wash quickly with cold water, and when that woke him
|
|
up he realized he had been dreaming. The sequence repeated four
|
|
times before he finally actually woke up - still in bed.
|
|
|
|
A student of mine described her infuriating recurrent dream of
|
|
getting up, cleaning her teeth, getting dressed, and then cycling
|
|
all the way to the medical school at the top of a long hill, where
|
|
she finally would realize that she had dreamed it all, was late
|
|
for lectures, and would have to do it all over again for real.
|
|
|
|
The one positive benefit of false awakenings is that they can
|
|
sometimes be used to induce out-of-body-experiences (OBEs).
|
|
Indeed, Oliver Fox (1962) recommends this as a method for
|
|
achieving the OBE. For many people OBEs and lucid dreams are
|
|
practically indistinguishable. If you dream of leaving your body,
|
|
the experience is much the same. Also recent research suggests
|
|
that the same people tend to have both lucid dreams and OBEs
|
|
(Blackmore 1988, Irwin 1988).
|
|
|
|
All of these experiences have something in common. In all of them
|
|
the "real" wolrd has been replaced by some kind of imaginary
|
|
replica. Celia Green, of the Institute of Psychophysical Research
|
|
at Oxford, refers to all such states as "metachoric experiences."
|
|
|
|
Jayne Gackenbach, a psychologist from the University of Alberta,
|
|
Canada, relates these experiences to UFO-abduction stories and
|
|
near-death-experiences (NDEs). The UFO abductions are the most
|
|
bizarre but are similar in that they too involve the replacement
|
|
of the perceived world by a hallucinatory replica.
|
|
|
|
There is an important difference between lucid dreams and these
|
|
other states. In the lucid dream one has insight into the state
|
|
(in fact that defines it). In false awakening, one does not (again
|
|
by definition). In typical OBEs, people think they have really
|
|
left their bodies. In UFO "abductions" they believe the little
|
|
green men are "really there"; and in NDEs, they are convinced they
|
|
are rushing down a real tunnel toward a real light and into the
|
|
next world. It is only in the lucid dream that one realizes it is
|
|
a dream.
|
|
|
|
I have often wondered whether insight into these other experiences
|
|
is possible and what the consequences might be. So far I don't
|
|
have any answers.
|
|
|
|
Waking Up
|
|
|
|
The oddest thing about lucid dreams - and, to many people who have
|
|
them, the most compelling - is how it feels when you wake up. Upon
|
|
waking up from a normal dream, you usually think, "Oh, that was
|
|
only a dream." Waking up from a lucid dream is more continuous. It
|
|
feels more real, it feels as though you were conscious in the
|
|
dream. Why is this? I think the reason can be found by looking at
|
|
the mental models the brain constructs in waking, in ordinary
|
|
dreaming, and in lucid dreams.
|
|
|
|
I have previously argued that what seems real is the most stable
|
|
mental model in the system at any time. In waking life, this is
|
|
almost always the input-driven model, the one that is built up
|
|
from the sensory input. It is firmly linked to the body image to
|
|
make a stable model of "me, here, now." It is easy to decide that
|
|
this represents "reality" while all the other models being used at
|
|
the same time are "just imagination" (Blackmore 1988).
|
|
|
|
Now consider an ordinary dream. In that case there are lots of
|
|
models being built but no input-driven model. In addition there is
|
|
no adequate self-model or body image. There is just not enough
|
|
access to memory to construct it. This means, if my hypothesis is
|
|
right, that whatever model is most stable at any time will seem
|
|
real. But there is no recognizable self to whom it seems real.
|
|
There will just be a series of competing models coming and going.
|
|
Is this what dreaming feels like?
|
|
|
|
Finally, we know from research that in the lucid dream there is
|
|
higher arousal. Perhaps this is sufficient to construct a better
|
|
model of self. It is one that includes such important facts as
|
|
that you have gone to sleep, that you intended to signal with your
|
|
eyes, and so on. It is also more similar to the normal waking self
|
|
than those fleeting constructions of the ordinary dream. This, I
|
|
suggest, is what makes the dream seem more real on waking up.
|
|
Because the you who remembers the dream is more similar to the you
|
|
in the dream. Indeed, because there was a better model of you, you
|
|
were more conscious.
|
|
|
|
If this is right, it means that lucid dreams are potentially even
|
|
more interesting than we thought. As well as providing insight
|
|
into the nature of sleep and dreams, they may give clues to the
|
|
nature of consciousness itself.
|
|
|
|
References
|
|
|
|
|
|
Blackmore, S. J. 1982. Beyond the Body. London: Heinemann.
|
|
--------- 1988. A Theory of lucid dreams and OBEs. In
|
|
Conscious Mind, Sleeping Brain, 373-387, ed.
|
|
J. Gackenbach and S. LaBerge. New York: Plenum.
|
|
Delage, Y. 1919. Le Reve. Paris: Les Presses Universitaires de
|
|
France.
|
|
Fox, O. 1962. Astral Projection. New York: University Books.
|
|
Gackenbach, J., and J. Bosveld. 1989. Control Your Dreams.
|
|
New York: Harper & Row.
|
|
Gackenbach, J., and S. LaBerge, eds. 1988. Conscious Mind,
|
|
Sleeping Brain. New York: Plenum.
|
|
Green, C. E. 1968. Lucid Dreams. London: Hamish Hamilton.
|
|
Hearne, K. 1978. Lucid Dreams: An Electrophysiological and
|
|
Psychological Study. Unpublished Ph.D.
|
|
thesis, University of Hull.
|
|
--------- 1990. The Dream Machine. Northants: Aquarian.
|
|
Irwin, H. J. 1988. Out-of-body experiences and dream lucidity:
|
|
Empirical perspectives. In Conscious Mind,
|
|
Sleeping Brain, 353-371, ed. J. Gackenbach
|
|
and S. LaBerge. New York: Plenum.
|
|
LaBerge, S. 1985. Lucid Dreaming. Los Angeles: Tarcher.
|
|
LaBerge, S. and W. Dement. 1982a. Voluntary control of
|
|
respiration during REM sleep. Sleep Research,
|
|
11:107.
|
|
--------- 1982b. Lateralization of alpha activity for dreamed
|
|
singing and counting during REM sleep.
|
|
Psychophysiology, 19:331-332.
|
|
LaBerge, S., W. Greenleaf, and B. Kerzierski. 1983.
|
|
Physiological responses to dreamed sexual
|
|
activity during lucid REM sleep.
|
|
Psychophysiology, 20:454-455.
|
|
Price, R. F., and D. B. Cohen. 1988. Lucid dream induction: An
|
|
empirical evaluation. In Conscious Mind,
|
|
Sleeping Brain, 105-134, ed. J. Gackenbach
|
|
and S. LaBerge. New York: Plenum.
|
|
Schatzman, M., A. Worsley, and P. Fenwick. 1988.
|
|
Correspondence during lucid dreams between
|
|
dreamed and actual events. In Conscious Mind,
|
|
Sleeping Brain, 155-179, ed. J. Gackenbach
|
|
and S. LaBerge. New York: Plenum.
|
|
Tart, C. 1988. From spontaneous event to lucidity: A review of
|
|
attempts to consciously control nocturnal
|
|
dreaming. In Conscious Mind, Sleeping Brain,
|
|
67-103, ed. J Gackenbach and S. LaBerge. New
|
|
York: Plenum.
|
|
Tholey, P. 1983. Techniques for controlling and manipulating
|
|
lucid dreams. Perceptual and Motor Skills,
|
|
57:79-90.
|
|
Van Eeden, F. 1913. A study of dreams. Proceedings of the
|
|
Society for Psychical Research, 26:431-461.
|
|
|
|
Susan J. Blackmore is with the Perceptual Systems Research
|
|
Centre, Department of Psychology, University of Bristol, and
|
|
the School of Social Sciences, University of Bath. |