ChapterPDF Available

Spontaneous Thought, Insight, and Control in Lucid Dreams

Authors:

Abstract

Dreams are sometimes described as an intensified form of spontaneous waking thought. Lucid dreams may seem to be a counterexample, because metacognitive insight into the fact that one is now dreaming is often associated with the ability to deliberately control the ongoing dream. This chapter uses conceptual considerations and empirical research findings to argue that lucid dreaming is in fact a promising and rich target for the future investigation of spontaneous thought. In particular, the investigation of dream lucidity can shed light on the relationship between metacognitive insight and control, on the one hand, and the spontaneous, largely imagistic cognitive processes that underlie the formation of dream imagery, on the other hand. In some cases, even lucid insight itself can be described as the outcome of spontaneous processes, rather than as resulting from conscious and deliberate reasoning. This raises new questions about the relationship between metacognitive awareness and spontaneous thought.
Spontaneous Thought, Insight, and Control in Lucid Dreams
Page 1 of 49
PRINTED FROM OXFORD HANDBOOKS ONLINE (www.oxfordhandbooks.com). (c) Oxford University Press, 2015. All Rights
Reserved. Under the terms of the licence agreement, an individual user may print out a PDF of a single chapter of a title in
Oxford Handbooks Online for personal use.
Subscriber: OUP-Reference Gratis Access; date: 14 April 2018
Abstract and Keywords
Dreams are sometimes described as an intensified form of spontaneous waking thought.
Lucid dreams may seem to be a counterexample, because metacognitive insight into the
fact that one is now dreaming is often associated with the ability to deliberately control
the ongoing dream. This chapter uses conceptual considerations and empirical research
findings to argue that lucid dreaming is in fact a promising and rich target for the future
investigation of spontaneous thought. In particular, the investigation of dream lucidity
can shed light on the relationship between metacognitive insight and control, on the one
hand, and the spontaneous, largely imagistic cognitive processes that underlie the
formation of dream imagery, on the other hand. In some cases, even lucid insight itself
can be described as the outcome of spontaneous processes, rather than as resulting from
conscious and deliberate reasoning. This raises new questions about the relationship
between metacognitive awareness and spontaneous thought.
Keywords: lucid dreams, insight, metacognition, control, consciousness, self-consciousness, spontaneous thought,
REM sleep
There is one very remarkable thing in dreams, for which I believe no one can give
a reason. It is the formation of visions by a spontaneous organization carried out
in a moment—a formation more elegant than any which we can attain by much
thought while awake. To the sleeper there often occur visions of great buildings
which he has never seen, while it would be difficult for me, while awake, to form
an idea of even the smallest house different from those I have seen, without a
great amount of thought. [ . . . ] Even such unnatural things as flying men and
innumerable other monstrosities can be pictured more skillfully than a waking
Spontaneous Thought, Insight, and Control in Lucid
Dreams
Jennifer M. Windt and Ursula Voss
The Oxford Handbook of Spontaneous Thought: Mind-Wandering, Creativity,
and Dreaming
Edited by Kalina Christoff and Kieran C.R. Fox
Print Publication Date: May 2018 Subject: Psychology, Cognitive Neuroscience
Online Publication Date: Apr 2018 DOI: 10.1093/oxfordhb/9780190464745.013.26
Oxford Handbooks Online
Spontaneous Thought, Insight, and Control in Lucid Dreams
Page 2 of 49
PRINTED FROM OXFORD HANDBOOKS ONLINE (www.oxfordhandbooks.com). (c) Oxford University Press, 2015. All Rights
Reserved. Under the terms of the licence agreement, an individual user may print out a PDF of a single chapter of a title in
Oxford Handbooks Online for personal use.
Subscriber: OUP-Reference Gratis Access; date: 14 April 2018
person can do, except with much thought. They are sought by the waker; they
offer themselves to the sleeper. There must therefore necessarily be some
architectural and harmonious principle, I know not what, in our mind, which,
when freed from separating ideas by judgment, turns to compounding them.
Leibniz (1956, Vol. I, pp. 177–178)
Dreams are often described as a paradigmatic example of spontaneous thought, or even
as an intensified form of waking mind-wandering (Domhoff, 2011; Fox, Nijeboer,
Solomonova, Domhoff, & Christoff, 2013; see also Domhoff, Chapter 27 in this volume).
Here, we approach this topic from the perspective of lucid dreaming, which we argue is a
key target for the investigation of spontaneous cognitive processes in sleep.
This strategy might seem surprising. Lucid dreams are characterized by metacognitive
insight into the fact that one is now dreaming, which is typically associated with the
ability to control the ongoing dream, as well as with dissociative phenomena, such as
seeing oneself from the outside (Voss & Hobson, 2015; Voss, Schermelleh-Engel,
Windt, Frenzel, & Hobson, 2013). For this reason, dream lucidity might seem to be an
obvious counterexample to the claim that dreaming is a form of spontaneous thought.
One possibility could be that dream control, coupled with metacognitive insight,
suppresses the spontaneous processes that underlie non-lucid dreaming. If this were the
case, lucid control dreams would be a subgroup of dreams in which the element of
spontaneity has been lost or at least greatly reduced. A slightly stronger view would be
that the example of lucid dreaming casts doubt on the claim that dreaming in general can
be described as a form of spontaneous thought. In both cases, the investigation of lucid
dreaming could not meaningfully contribute to a discussion of spontaneous thought.
In this chapter, we argue that the opposite is true. Contrary to first appearances, lucid
dreams are in fact a rich target phenomenon for investigating, both conceptually and
experimentally, spontaneous cognitive processes in sleep, as well as their interplay with
volitional control, metacognitive insight, and dissociative phenomena. Lucid dreams show
that metacognitive insight and control are not necessarily opposed to spontaneity, but
that the two can coexist alongside one another. Dissociation plays a particularly
important role in this context, as it is itself the outcome of spontaneous cognitive
processing, but nonetheless may facilitate the occurrence of insight and control.
We begin by offering some general considerations on the description of dreaming as a
form of spontaneous thought. In the second section of the chapter, we give an overview of
the main empirical findings on lucid dreaming, with special emphasis on the role of
cognition and volition as key determinants of lucidity, as well as on the underlying
neurophysiological processes. We suggest that the spontaneous aspects of dream lucidity
are most probably related to the involvement of not only cortical but also subcortical
brain structures. The third section raises a number of more general theoretical questions
about the relationship between lucid insight, dream control, and the subjectively realistic
and often unexpected elements of lucid dreams. We conclude that lucid dreams are
spontaneously occurring mental states in which lower-level imagistic cognitive processing
(p. 386)
Spontaneous Thought, Insight, and Control in Lucid Dreams
Page 3 of 49
PRINTED FROM OXFORD HANDBOOKS ONLINE (www.oxfordhandbooks.com). (c) Oxford University Press, 2015. All Rights
Reserved. Under the terms of the licence agreement, an individual user may print out a PDF of a single chapter of a title in
Oxford Handbooks Online for personal use.
Subscriber: OUP-Reference Gratis Access; date: 14 April 2018
is largely unpredictable and beyond the reach of volitional control. This explains both the
continuity between lucid and non-lucid dreams and why lucid insight is often
accompanied by illogical thought. The fourth and last section raises questions and
challenges for future research, with a specific focus on the comparison between lucid
dreams and spontaneous thought in wakefulness.
Is Dreaming a Kind of Spontaneous Thought?
Spontaneous thought is sometimes used as a blanket term for a range of mental activities
involving mind-wandering, daydreaming, and creativity. All of these are commonly
contrasted with goal-directed thought (Christoff, Gordon, Smith, Vartanian, & Mandel,
2011; Fox & Christoff, 2014; Christoff et al., 2016) and are described as being largely
independent of sensory stimuli and ongoing tasks (Smallwood & Schooler, 2015). While
the early literature focused on the detrimental effects of mind-wandering on cognitive
performance and mood (Killingsworth & Gilbert, 2010; Schooler et al., 2011), the newer
literature emphasizes possible benefits, such as creativity, future planning, and memory
consolidation (Fox & Christoff, 2014; McMillan, Kaufman, & Singer, 2013; Smallwood &
Andrews-Hanna, 2013; Smallwood & Schooler, 2015). Philosophers have been slow to
consider empirical research on mind-wandering, but a discussion on the nature of mind-
wandering and its relationship to attention, goal-directed thought, and cognitive agency
is now slowly taking shape (Carruthers, 2015; Dorsch, 2015; Irving, 2016; Metzinger
2013, 2015). For now, we wish to remain noncommittal about the details of these different
emerging positions; rather than starting out with a closely circumscribed notion of
spontaneous thought and mind-wandering, we begin with a fairly loose working
definition, with the hope that our discussion of lucid dreaming can help fill in the details.
With this restriction in mind, we will (unless explicitly indicated otherwise) use the terms
spontaneous thought and mind-wandering interchangeably to denote conscious cognitive
processes (including memories and emotions) that are largely determined by intrinsic
brain activation and only weakly constrained by ongoing tasks and the demands of the
external environment (Smallwood & Schooler, 2015; Christoff et al., 2016). Importantly,
episodes of spontaneous thought involve phenomenal consciousness. There can be
something it is like to experience a vivid daydream even if one does not realize that one’s
thoughts have wandered away from the task at hand; the episode still has subjective,
qualitative character. At least retrospectively, after the daydream has terminated, one will
also often be able to report its occurrence and describe its subjective or
qualitative character—even though the exact contents and the subtle phenomenological
details can be strangely elusive (for the difference between self- and probe-caught
episodes of mind-wandering, see Schooler et al., 2011; for a general discussion of the
difficulty of reporting spontaneous fantasies, see Schwitzgebel, 2011; Windt, 2015a,
Chapter 4).
1
(p. 387)
Spontaneous Thought, Insight, and Control in Lucid Dreams
Page 4 of 49
PRINTED FROM OXFORD HANDBOOKS ONLINE (www.oxfordhandbooks.com). (c) Oxford University Press, 2015. All Rights
Reserved. Under the terms of the licence agreement, an individual user may print out a PDF of a single chapter of a title in
Oxford Handbooks Online for personal use.
Subscriber: OUP-Reference Gratis Access; date: 14 April 2018
All of this is, it would seem, directly applicable to dreaming. Even though (with the
exception of lucid dreaming) we do not realize that we are dreaming while we are
dreaming, dreams are reportable experiences. This is compatible with saying that most
dreams are in fact forgotten; the main point is that under appropriate conditions—such as
following timed awakenings in the sleep laboratory—dreams and other experiences
occurring in sleep can be remembered and reported (Windt, 2013, 2015a, b).
Dreams are also commonly taken to be a paradigmatic example of subjective or
phenomenal experience unfolding almost completely independently of sensory input and
motor output (Metzinger, 2004; Revonsuo, 2006). Mind-wandering involves sensory
attenuation, a dampening, as it were, of environmental and peripheral bodily stimuli
(Kam & Handy, 2013). During dreaming, this disconnection is even stronger. Rapid eye
movement (REM) sleep paralysis mostly prevents the outward enactment of movements
experienced within the dream, and responsiveness to environmental stimuli is greatly
reduced or even absent (Hobson et al., 2000). This is not quite to say that dreaming is
entirely independent of contemporaneous sensory stimuli—dream experience continues
to be modulated by bodily sensations (Nielsen, 1993), and sounds or smells in the
sleeper’s environment can also leave their mark on dreams (Rahimi et al., 2015; Schredl
et al., 2009; for discussion and further references, see Windt 2015a, Chapter 8; Windt,
2017). But where the daydreaming mind is briefly distracted, as it were, by its own
musings, sleep is the naturally and regularly occurring state in which we come closest to
almost completely losing our perceptual and cognitive grip on our surroundings.
While the onset and timing of sleep can, to an extent, be deliberately controlled,
dreaming itself is typically held to be involuntary and perhaps even incontrollable. The
opposition between dreaming and volitional control has a long history, and philosophers
have traditionally found the unruly nature of dreaming to be quite disturbing. Augustine
(1991) famously wondered whether he was morally responsible for sins committed in his
dreams, such as adultery, but finally decided that he was not. The chasm between sleep
and wakefulness was just too great, he thought, for dreams to be a cause of moral
concern. The involuntariness of dreaming is also connected to the epistemological
problem of dream skepticism: it is precisely because dreams confront us with a seemingly
realistic, mind-independent world that they are thought to be deceptive (Descartes,
2013). Others, perhaps most notably Leibniz (1956), were fascinated by the spontaneous
character of dreams, but also by their vivacity and creativity, which were thought to
exceed the imaginative abilities of the waking mind. But the predominant view is that
dreaming is a state of cognitive deficiency resulting from a loss of critical thought and
volition, comparable to pathological wake states such as hallucinations and delusions
(Hobson, 1999; see Windt & Noreika, 2011, for discussion and further references).
The involuntary and allegedly deceptive character of dreaming is closely related to the
vividness of dream imagery and the intensity of dream emotions. But this also points to a
difference between dreaming and waking mind-wandering. Dreams are immersive in a
way that even vivid daydreams are not (Fox et al., 2013); while the ongoing flow of
sensory perception prevents us from getting completely lost in a daydream, we feel more
Spontaneous Thought, Insight, and Control in Lucid Dreams
Page 5 of 49
PRINTED FROM OXFORD HANDBOOKS ONLINE (www.oxfordhandbooks.com). (c) Oxford University Press, 2015. All Rights
Reserved. Under the terms of the licence agreement, an individual user may print out a PDF of a single chapter of a title in
Oxford Handbooks Online for personal use.
Subscriber: OUP-Reference Gratis Access; date: 14 April 2018
robustly present in our dreams in part because there are less competing sensory stimuli,
as well as fewer critical thoughts that could counteract this feeling of presence (Windt,
2015a, Chapter 12).
While scientific dream research long suffered from the lack of a commonly agreed-upon
definition, there is now increasing agreement that dreaming is a kind of conscious mental
simulation (Revonsuo Tuominen, & Valli, 2015a, 2015b). According to these simulation
views, dreaming involves the experience of being a self in a world. While the details
differ, this convergence is an important step toward a unified theory of dreaming. At the
same time, the description of dreaming as involving world simulation is, however,
antithetical to the claim that dreaming is a kind of spontaneous thought, at least where
this is understood as a phenomenological claim. Because of their immersive character as
well as their apparent uncontrollability, dreams feel distinctly unlike waking thoughts.
Importantly, to ask whether dreaming is a spontaneous thought process is different from
asking whether spontaneous thoughts occur in dreams. The first question, unlike the
second one, is not about whether in a dream, the dream self, or the character with which
I identify in the dream, experiences spontaneous thoughts, or indeed any
thoughts at all; it asks whether the process of dreaming as such can be meaningfully
described as a kind of thinking. Dreaming involves spontaneous mental activity during
sleep, but on the phenomenological level of description, it is not a kind of thinking. Only
the thoughts experienced by the dream self, within the dream, are thoughts in this
phenomenological sense.
This move minimizes conceptual ambiguity. As noted earlier, there is a long tradition,
both in philosophy and in scientific dream research, of describing dreaming as a state of
cognitive deficiency in which conscious thought and self-reflection are either completely
absent or, if present, are irrational and confused, resembling wake-state delusions and
confabulation (Hobson, 1999; Hobson, Pace-Schott, & Stickgold, 2000; Metzinger, 2004).
Roughly, if dreaming is itself conceived of as a kind of thinking, this leaves little room for
conscious thought processes occurring within the dream (McGinn, 2009; empirical
support for this view comes from Fosse, Stickgold, & Hobson, 2001, 2004). This view,
however, is likely too restrictive: Even non-lucid dreams often involve the phenomenology
of thinking (Kahan, 2001; Kahn & Hobson, 2005; see Windt, 2015a, Chapter 9, for
discussion and further references). By reserving the term conscious thought for thoughts
experienced within a dream and by the dream self, we want to propose that investigating
the relationship between conscious thought and the lower-level, largely imagistic
cognitive processes that make up the experienced dream world and the dream self is a
worthwhile project.
What about spontaneity? As noted earlier, spontaneous thought is standardly contrasted
with attention and goal-directedness (Christoff et al., 2011), though this does not exclude
the possibility that mind-wandering can still be guided by unconscious goals. According
to Smallwood and Schooler (2015), the crucial factor is that in mind-wandering, thought
contents are self-generated, meaning that they are determined intrinsically, rather than
directly cued by sensory input. We have to tread carefully here though, because the
2
(p. 388)
3
4
Spontaneous Thought, Insight, and Control in Lucid Dreams
Page 6 of 49
PRINTED FROM OXFORD HANDBOOKS ONLINE (www.oxfordhandbooks.com). (c) Oxford University Press, 2015. All Rights
Reserved. Under the terms of the licence agreement, an individual user may print out a PDF of a single chapter of a title in
Oxford Handbooks Online for personal use.
Subscriber: OUP-Reference Gratis Access; date: 14 April 2018
notion of self-generated, conscious mental activity is, again, ambiguous. On the strongest
reading, we might want to say that for a mental state to be self-generated, it must be
experienced as being generated by oneself and as actually being under one’s control.
Metzinger (2013, 2015) argues that cognitive agency of this sort is exactly what is lost in
episodes of mind-wandering. As he puts it, “during full-blown episodes of mind-
wandering, we are not epistemic agents, neither as controllers of attentional focus nor as
deliberate thinkers of thoughts, and we have forgotten about our agentive abilities” (p.
282, 2015). He casts mind-wandering as a subpersonal process, akin to breathing: It is
not something we, as persons, do; it is something that happens to us, that we cannot
control, and of whose occurrence we are typically unaware. It is only after gaining
metacognitive insight into the fact that our minds have wandered that we once again
acquire the ability for self-determined thought and cognitive agency. But because this
also terminates the episode itself, mind-wandering cannot be described as a self-
generated or self-determined process.
What we need to describe spontaneous thoughts as self-generated, then, is a weaker
reading of spontaneity that encompasses internally generated behaviors and not just
personal-level mental actions. Hanna and Thompson (2003) appear to take this kind of
view, writing that “subjective experience is partially constituted by its being at once
underdetermined or uncontrolled by external influences (inner plasticity), and also self-
determining or self-controlling (inner purposiveness)” (p. 137). Using largely automatic
shifts in multi-stable images (such as switching back and forth between two
interpretations of Wittgenstein’s duck-rabbit) as an example, they explain that the
spontaneity of conscious experience is “constituted by the fourfold fact that the precise,
qualitative character of conscious states (1) is not determined by anything external to the
conscious subject; (2) is self-generated; (3) is not self-generated by a prior conscious
intention; and yet (4) can under some conditions be controlled by a conscious
intention” (p. 147). What they mean by self-generated but nonetheless spontaneous
mental states is consequently more inclusive than Metzinger’s sense; it encompasses
lower-level shifts in brain dynamics as well as attempts to deliberately bring these about.
Spontaneous thought is not necessarily sub-personal, but can even be guided by
intentions, as long as these intentions themselves are formed, as it were, on the fly.
Here, we opt for this weaker type of account, in which spontaneity refers to conscious
mental events that subjectively are experienced as internally caused or self-determined,
rather than being tightly constrained either by ongoing tasks and environmental stimuli
or by pre-existing conscious intentions. This notion of spontaneity will be most useful for
cases that nonetheless have the potential for coming under our deliberate control;
spontaneous mental events are not in fact guided by previous intentions, but they
could be. Moreover, because spontaneity of this type is a phenomenological notion, there
is no requirement that the experience of spontaneity be veridical: even though I
experience my thoughts, for instance, as unfolding independently of external conditions
and previous intentions, this impression could be false; I might simply fail to be aware of
(p. 389)
Spontaneous Thought, Insight, and Control in Lucid Dreams
Page 7 of 49
PRINTED FROM OXFORD HANDBOOKS ONLINE (www.oxfordhandbooks.com). (c) Oxford University Press, 2015. All Rights
Reserved. Under the terms of the licence agreement, an individual user may print out a PDF of a single chapter of a title in
Oxford Handbooks Online for personal use.
Subscriber: OUP-Reference Gratis Access; date: 14 April 2018
what is actually causing the shifts in my ongoing experience. Subjective impressions of
spontaneity can be deceptive.
This distinction between the first-person phenomenological reading of spontaneity and
the third-person epistemological one is important for methodological reasons: For
investigating the contents of mind-wandering episodes, but also dreams, one has to rely
on self-report, and so the participant’s own judgment will be crucial for identifying
spontaneous mental processes and distinguishing them from those that were experienced
as deliberately controlled or directly prompted by external sensory stimuli. An interesting
next step, then, would be to investigate the extent to which subjectively spontaneous
daydreams are in fact closely modulated by external sensory cues.
How does this phenomenological conception of spontaneity apply to the case of sleep and
dreaming? On the one hand, the occurrence of sleep and dreaming is certainly
spontaneous in the sense of being internally rather than externally regulated. On the
other hand, the timing and duration of sleep and dreaming are highly ordered processes.
Sleep is governed by a circadian rhythm, and sleep architecture is made up of cyclically
recurring sleep stages. The timing of sleep is mostly driven internally and to a lesser
degree is modulated by external influences, such as lighting. The timing of sleep can also
be controlled deliberately, but only to an extent. To be sure, I can intend to go to sleep
and dream and to deliberately stay awake beyond my bedtime. It is noteworthy, however,
that such attempts to deliberately control the onset of sleep can also be disruptive and
may even be one of the factors leading to insomnia. As Espie and colleagues (2006) put it,
“sleep–wake automaticity can be inhibited by selectively attending to sleep, by explicitly
intending to sleep, and by introducing effort into the sleep engagement process” (p. 217).
Something similar seems to be true for dreaming. The sleep-stage correlates of dreaming
remain controversial and it is now commonly recognized that dreams occur in all stages
of sleep (Nielsen, 2000, 2014; Windt et al., 2016). Yet if we focus on the example of REM-
sleep dreams, it is clear that the timing and duration of dreaming are again
systematically controlled and intrinsically orchestrated. Dream reports increase in length
as the duration of REM periods increases throughout the night, and generally, dream
reports from the second half of the night are more vivid and emotionally intense, as well
as longer than reports from the first half of the night (Domhoff, 2013; Kramer, 2013). The
rhythmic and carefully orchestrated timing of sleep and dreaming appears to set them
apart from spontaneous waking thoughts, which do not seem to adhere to any close
schedule, either internal or external.
Do the contents of dreams have a similarly ordered nature as the timing and duration of
dreaming? It is now increasingly clear that the different stages of sleep contribute to
different kinds of memory consolidation (Diekelmann & Born, 2010; Stickgold, 2005),
even though the exact mechanisms underlying the formation of dream content remain
unclear. In some accounts, the contents of dreams are without specific function or
meaning, the product of random, brain-stem driven activation (Hobson et al., 2000). But
there is also much evidence that dream content has an ordered nature, for instance by
5
Spontaneous Thought, Insight, and Control in Lucid Dreams
Page 8 of 49
PRINTED FROM OXFORD HANDBOOKS ONLINE (www.oxfordhandbooks.com). (c) Oxford University Press, 2015. All Rights
Reserved. Under the terms of the licence agreement, an individual user may print out a PDF of a single chapter of a title in
Oxford Handbooks Online for personal use.
Subscriber: OUP-Reference Gratis Access; date: 14 April 2018
being continuous with waking experiences, thoughts, and concerns (Domhoff, 2013).
Research on the so-called dream-lag effect suggests that there is a temporal pattern for
the incorporation of waking memories in dreams, such that we are most likely to dream of
events experienced the preceding day (“day residue”), but also of those experienced 5–7
days before, and less likely to dream of events from days 2–4 before (see van Rijn et al.,
2015, for discussion and further references). This effect is specific to REM-sleep dreams.
Moreover, the memory sources of sleep mentation become increasingly remote
throughout the night, often involving semantically related memories from different
periods of one’s life (such as two pets that one had at different times; Stenstrom, Fox,
Solomonova, & Nielsen, 2012; see also Verdone, 1965). Currently, however, too little is
known about the contents of dreams and their relation to waking life events to reach any
final verdict on this question.
Another relevant distinction is between the content of dreams and the formal features of
dreaming. Broadly speaking, content analysis is interested in the topics one dreams about
and their relation to current concerns or real-life experiences (Domhoff, 2013), whereas
formal analysis focuses on the types of imagery (visual, auditory, etc.) and emotions
associated with these contents (Hobson, 1988). It is noteworthy that the formal
features of dreaming seem to be much more generic than the contents of dreaming,
which are harder to predict and more idiosyncratic. Movement sensations, for instance,
are described almost as frequently in the dreams of congenital paraplegics as they are in
those of healthy participants (Voss, Tuin, Schermelleh-Engel, & Hobson, 2011). By
comparison, the contents of dreaming are much harder to predict—and this
unpredictability is a major challenge to the scientific investigation of dreaming and its
contribution, if any, to memory consolidation in sleep. Generally, the most promising
targets for investigating spontaneous conscious processes will be those that have the
highest degree of inter-individual variation, have the potential to be deliberately
controlled, and are the hardest to predict. This is likely the case for the content of
dreaming, but not for its formal features, nor for its timing and duration.
This is why dream lucidity is directly relevant to questions concerning the spontaneity of
dreaming. Dream lucidity is often associated with the ability to control the ongoing dream
at will. As will become clear later, the clearest examples of dream control concern the
contents rather than the formal features of lucid dreams; and often, control is exercised
in response to spontaneously formed intentions. At the same time, the ability of
experienced lucid dreamers to act upon previously formed intentions can turn specific
forms of dream content into a systematically investigable and to an extent predictable
target for laboratory dream research. We now turn to a brief summary of the main
research findings on dream lucidity.
(p. 390)
Spontaneous Thought, Insight, and Control in Lucid Dreams
Page 9 of 49
PRINTED FROM OXFORD HANDBOOKS ONLINE (www.oxfordhandbooks.com). (c) Oxford University Press, 2015. All Rights
Reserved. Under the terms of the licence agreement, an individual user may print out a PDF of a single chapter of a title in
Oxford Handbooks Online for personal use.
Subscriber: OUP-Reference Gratis Access; date: 14 April 2018
Lucid Dreaming: A Brief Review of the Main
Scientific Findings
Lucid dreaming is associated with changes in subjective experience and cognitive
functioning that are atypical for ordinary REM-sleep dreams. In its purest form, a lucid
dream is accompanied by insight into the fact that one is dreaming while the dream
continues, meaning that the dreamer is aware of the fact that what they are now
experiencing is virtual, not real. A less conservative yet empirically substantiated
definition includes dreams that are additionally accompanied by heightened control and/
or dissociative elements (see Voss et al., 2013; Voss & Hobson, 2015, for discussion and
further references). Lucid dreams may be entered from wakefulness by means of
meditative relaxation or hypnagogic/hypnopompic states during sleep onset (wake-
initiated lucid dreams, or WILDs) or develop spontaneously out of REM sleep (REM-
initiated lucid dreams, sometimes also referred to as dream-initiated LDs, or DILDs; see
LaBerge, 1990). Even though the frequency of lucid dreaming can be augmented through
autosuggestion and training, it has not, so far, been possible to reliably predict the timing
of a lucid dream, and the success rate for different lucid dream induction techniques is
still comparatively small (Stumbrys, Erlacher, Schädlich, & Schredl, 2012).
Especially during childhood and early adolescence, lucid dreams appear to occur
spontaneously and without previous effort or intent (Schredl et al., 2012; Voss et al.,
2012). In adulthood, REM-initiated lucid dreams are much less frequent, and in our
experience, many participants experience this method as more difficult to master
successfully. Once lucid, adults also find lucidity more difficult to maintain. Especially for
participants with no previous lucid dream experience, lucid dreams appear to be much
easier to initiate from wakefulness, and so this method enjoys great popularity. We
therefore assume that most lucid dream reports posted on Internet platforms refer to
WILD dreams in which the dreamer uses either meditative relaxation or hypnagogic/
hypnopompic states to enter a lucid dream during sleep onset.
With regard to emotion, it is noteworthy that many lucid dreams reported on Internet
platforms and in the lucid dream literature are described as positive or even euphoric. By
contrast, the majority of lucid dreams investigated in laboratory studies are emotionally
neutral (Voss et al., 2013; Voss et al., 2014), suggesting that an effect of lucidity on
emotions cannot be considered conclusively established. According to the participants in
our study (Voss et al., 2013), lucid dreams occurring in the laboratory were generally also
shorter and more difficult to maintain than those experienced at home. Further, they
were all initiated from REM sleep.
Several different interpretations are available. One is that the difference in emotional
tone is due to an underlying contrast between REM-initiated lucid dreams and WILDs.
Another is that the sleeping environment influences the emotional tone of lucid dreams
independently of whether they were initiated from wakefulness or from REM sleep. A
Spontaneous Thought, Insight, and Control in Lucid Dreams
Page 10 of 49
PRINTED FROM OXFORD HANDBOOKS ONLINE (www.oxfordhandbooks.com). (c) Oxford University Press, 2015. All Rights
Reserved. Under the terms of the licence agreement, an individual user may print out a PDF of a single chapter of a title in
Oxford Handbooks Online for personal use.
Subscriber: OUP-Reference Gratis Access; date: 14 April 2018
third possible explanation could be that the euphoria anecdotally ascribed to lucid
dreams actually sets in after awakening. In this reading, the dreamer would experience
euphoria about just having been able to produce a lucid dream, but these positive
emotions would not necessarily have been present in the dream itself. For
subjects awakened directly following a REM phase in the laboratory, the experimental
protocol and the perceived pressure to produce and report a lucid dream may counteract
this euphoria. The positive emotional tone of lucid dreams would then be an artifact of
the sleeping environment and the conditions under which the dream is reported. This
question has not, to our knowledge, been investigated experimentally, but it would fit in
well with the fact that timed awakenings in the sleep laboratory are generally regarded
as the gold standard for gathering reliable dream reports.
Scientifically, REM-initiated lucid dreams are very appealing because they present a
unique opportunity to study the neuro- and electrophysiological correlates of emerging
metacognitive awareness and executive ego functions (e.g. logical thought, self-reflection,
decision-making, and volition) against a background of a steady state (i.e., a relatively
stable state of arousal). Lucidity is plausibly related to a change in self-related processing
and (meta-)cognitive functioning (Metzinger, 2004; Windt & Metzinger, 2007). For lucid
dreams emerging from non-lucid REM-sleep dreams, it therefore becomes possible to
contrast the transition between different levels of subjective experience and cognitive
functioning, as well as their neural correlates. By contrast, because WILDs are set
against a background state that is ambiguous and constantly fluctuating between
wakefulness and sleep onset, the assignment of subjective (dream report) and objective
(neuroimaging data, EEG) data represents an even greater challenge than for REM-
initiated lucid dreams. With regard to REM-initiated lucid dreams, data from different
laboratories have identified several typical patterns of brain activation, including a frontal
REM-atypical increase in lower gamma frequency band activity (Voss, Holzmann, Tuin, &
Hobson, 2009), as well as an augmented activation of frontotemporal (Dresler et al.,
2012) and frontopolar cortical areas (Filevich, Dresler, Brick, & Kühn, 2015).
(p. 391)
6
Spontaneous Thought, Insight, and Control in Lucid Dreams
Page 11 of 49
PRINTED FROM OXFORD HANDBOOKS ONLINE (www.oxfordhandbooks.com). (c) Oxford University Press, 2015. All Rights
Reserved. Under the terms of the licence agreement, an individual user may print out a PDF of a single chapter of a title in
Oxford Handbooks Online for personal use.
Subscriber: OUP-Reference Gratis Access; date: 14 April 2018
History of Lucid Dreaming
Dreams involving metacognitive insight into the fact that one is now dreaming have been
known since antiquity (Aristotle, 1996), but first became a target of experimental
research in the late nineteenth century (Maury, 1861; Saint-Denys, 1982). The term lucid
dreaming was coined by van Eeden at the beginning of the twentieth century. Van Eeden
was mainly interested in using lucid dreams as a vehicle for self-experimentation and self-
observation, for instance for describing the sheer variety of dreams and sleep-related
conscious experiences (van Eeden, 1913; see also Arnold-Forster, 1921). The crucial step
toward the laboratory-based scientific investigation of lucid dreaming occurred in the
1980s. Stephen LaBerge (1985, 1990) in the United States and Keith Hearne (1978) in
Great Britain introduced a methodological approach enabling an outside observer to
monitor the progression of lucid dreams via voluntary eye movements made by the
dreamer. By conducting a previously arranged pattern of gaze shifts (for instance, right,
left, right, left) in their lucid dreams, participants can control their actual eye movements;
these eye movement patterns then show up on electro-oculogram (EOG) recordings of eye
muscle movements. When participants confirm, after awakening, that they indeed were
lucid and performed the gaze shifts within their dream, the foregoing sleep phases can be
scored as lucid (so-called signal-verified lucid dreams). In Germany, it was primarily Paul
Tholey (Tholey & Utecht, 1987) who focused on the scientific aspects of lucid dreams. He
introduced the German word “Klartraum,” which can be roughly translated as “clear
dream” and is meant to describe the overall clarity of reasoning and of dream imagery in
the lucid dream state.
These early developments notwithstanding, the scientific study of lucid dreaming did not
receive the recognition it deserved until the early twenty-first century. Instead, lucidity
was mostly ascribed to parapsychology and esotericism, perhaps owing to the strong
interest it received in these circles (e.g., Green, 1968). A long-held belief in the scientific
community was that lucid dreams were not sleep phenomena per se, but instead were
somnolent experiences arising out of brief arousals (Hartmann, 1975). This assumption is
appealing at first sight and may indeed accurately characterize at least a subgroup of
WILDs. However, at least for REM-initiated lucid dreams, this view has been refuted. As
recent electroencephalograph (EEG) (Voss et al., 2009) and fMRI studies (Dresler et al.,
2012) show, these lucid dreams alter REM sleep without suspending the state of sleep.
There is now solid scientific evidence for saying that REM-initiated lucid dreams are
genuine sleep phenomena, rather than artifacts of intermittent awakenings from sleep.
Definitions of Lucid Dreaming
Up until now, several definitions of lucid dreaming have existed alongside each other.
Major differences in existing definitions pertain to the level of voluntary control
and overall cognitive functioning, including the availability of waking memory and critical
reasoning ability. Some authors regard insight into the fact that one is now dreaming as
(p. 392)
Spontaneous Thought, Insight, and Control in Lucid Dreams
Page 12 of 49
PRINTED FROM OXFORD HANDBOOKS ONLINE (www.oxfordhandbooks.com). (c) Oxford University Press, 2015. All Rights
Reserved. Under the terms of the licence agreement, an individual user may print out a PDF of a single chapter of a title in
Oxford Handbooks Online for personal use.
Subscriber: OUP-Reference Gratis Access; date: 14 April 2018
the sole defining feature (LaBerge, 1985), whereas others apply a broader definition of
lucid dreams as involving full intellectual clarity, including the availability of
autobiographic memory sources, the ability to actively control the dream, as well as an
overall increase in the intensity of multimodal hallucinatory imagery (Tart, 1988). An
important question is whether the coexistence of these factors is strictly necessary, or if
any of these factors is sufficient for classifying a dream as lucid even when it occurs in
isolation from the other factors. Can a dream be called lucid only when the dreamer
reports having exercised dream control, for instance by altering the course of the dream?
If yes, how much control would be needed to do so? And would dream control be
sufficient to score a dream as lucid even if the report did not explicitly describe that the
dreamer was aware that she had been dreaming?
With the help of the Lucidity and Consciousness in Dreams scale (LuCiD scale; Voss et al.,
2013), we attempted to construct a tool that identifies the different determinants of
consciousness in dreams and allows for their measurable quantification. The LuCiD scale
was developed by an interdisciplinary team of researchers from psychology (Ursula Voss
and Clemens Frenzel), philosophy (Jennifer Windt), statistics (Karin Schermelleh-Engel),
and psychiatry (Allan Hobson). Its purpose was to put theory-based assumptions about
dream lucidity to the test and establish concrete differences between normal REM sleep
dreams and lucid dreams. Structural factor analysis revealed that unambiguous lucid
dreams (i.e., those accompanied by insight) were also reported to contain control over the
dream plot as well as dissociative experiences. In lucid dreams, dreamers typically also
were able to voluntarily change objects (control), and they often saw themselves from the
outside, reminiscent of autoscopic phenomena or out-of-body experiences (OBEs; see
Blanke & Mohr, 2005). Often, participants reported having experienced the dream as an
observer rather than actively participating in the dream, for instance saying that the
dream “played out like a movie.” We concluded that the three factors that most clearly
distinguish lucid dreams (where this refers to dreams identified as lucid by our
participants) from non-lucid ones are (1) insight into the fact that one is currently
dreaming, (2) control over the dream plot, and (3) dissociation akin to de-personalization
and de-realization. These three factors are correlated, meaning that in the majority of
lucid dreams, they will occur together.
Still, this is not the same as saying that any or all of these factors are strictly necessary
for lucidity to occur. Statistically speaking, it is possible that a dream can be considered
as lucid even in the absence of insight but, instead, in the presence of only dissociation
and control. For now, however, this point is primarily of theoretical interest. For
methodological reasons, we assume that insight is a core factor of lucidity, meaning that
while explicit insight may or may not co-occur with control and dissociation, a dream
cannot be scored as lucid unless the dream report explicitly describes that the dreamer
realized, in the dream, that she was now dreaming. This assumption is also in line with
the fact that in all studies conducted thus far, the categorization of a dream as lucid was
7
Spontaneous Thought, Insight, and Control in Lucid Dreams
Page 13 of 49
PRINTED FROM OXFORD HANDBOOKS ONLINE (www.oxfordhandbooks.com). (c) Oxford University Press, 2015. All Rights
Reserved. Under the terms of the licence agreement, an individual user may print out a PDF of a single chapter of a title in
Oxford Handbooks Online for personal use.
Subscriber: OUP-Reference Gratis Access; date: 14 April 2018
based at least in part on subjects’ claims that they had achieved insight in their dream
(for discussion, see Windt, 2015a, Chapter 4).
Finally, it is important to note that the factors of insight, control, and dissociation are
themselves internally complex and can vary by degree. For instance, lucid dreamers may
be able to control their own actions, but not those of other dream characters; or
dreamers may know they are dreaming but not realize the full consequences of this fact.
Therefore, we must also ask how much of lucid insight, control, and/or dissociative
elements suffice to justify the label “lucid,” and one advantage of the LuCiD scale is that
it allows us to tease apart these different factors. Being able to determine the
quantitative level of different aspects of dream experience is an important research
target because it enables not just an empirically informed definition of lucid dreaming,
but also its measurability and predictability (Noreika, Windt, Lenggenhager, & Karim,
2010; Voss & Hobson, 2015; Voss & Voss, 2014). It is also a condition for transferring
insights from the investigation of dream lucidity to clinically relevant altered conscious
states such as locked-in-syndrome or vegetative state (see, for instance, Naro, Bramanti,
Leo, Russo, & Calabro, 2016).
Brain-Physiologic Correlates of Lucid Dreaming
In the tradition of Freud, sleep is often still defined as a state of unconsciousness. The
question of whether dreams are conscious experiences occurring in sleep dominated the
philosophical discussion of sleep and dreaming well into the twentieth century
(Dennett, 1976; Malcolm, 1962). Today, most accept that dreams are phenomenal states;
they have qualitative or subjective character, meaning there is something it is like to
dream, and not just to remember having dreamed (see Windt, 2013, for discussion).
Moreover, since the discovery of REM sleep and its correlation with dreaming in the
1950s (Aserinsky & Kleitman, 1953; Dement & Kleitman, 1957), dreams have turned into
a target of scientific investigation. The science of lucid dreaming is the next and latest
step in this development. The investigation of dream lucidity and its contrast with non-
lucid dreams is particularly promising because the method of signal-verified lucid
dreaming, combined with retrospective dream reports, allows researchers not only to
determine when specific types of dream experience—such as performing a gymnastics
routine (Erlacher et al., 2013) or clenching one’s fist (Dresler et al., 2012)—are occurring
in real time, but also to time their duration and identify their neural correlates.
Our studies on lucid dreams show that consciousness in sleep is also susceptible to
experimental manipulation, allowing us to go beyond correlation to investigate the causal
contribution of different brain activation patterns to conscious experience in sleep. This
shows that changes in the level of experience of the type that accompany the onset of
lucidity can be initiated not only spontaneously or with the help of different cognitive
methods such as autosuggestion (Voss et al., 2009), but also via electrical stimulation of
relevant brain areas (Voss et al., 2014). Importantly, this is even the case when
participants are not themselves experienced lucid dreamers and do not use any of the
(p. 393)
Spontaneous Thought, Insight, and Control in Lucid Dreams
Page 14 of 49
PRINTED FROM OXFORD HANDBOOKS ONLINE (www.oxfordhandbooks.com). (c) Oxford University Press, 2015. All Rights
Reserved. Under the terms of the licence agreement, an individual user may print out a PDF of a single chapter of a title in
Oxford Handbooks Online for personal use.
Subscriber: OUP-Reference Gratis Access; date: 14 April 2018
cognitive techniques that are typically used to induce lucidity. Results on
electrophysiology and subjective experience in lucid and non-lucid dreams suggest that
lucid dreaming represents an extraordinary state of consciousness in which EEG
correlates of waking coexist with those typical for REM sleep dreaming (Voss et al., 2009;
Voss et al., 2014).
Figure 29.1 shows that at the cortical level, frontal and temporal areas appear to be
activated to a degree that is atypical of ordinary REM sleep (Dresler et al., 2012; Voss et
al., 2009), especially in the lower gamma frequency band centered around 40 Hz (Voss et
al., 2009). Although much reduced from waking, 40 Hz activity over the frontal,
dorsolateral, and prefrontal cortices is more akin to waking than to sleep. As is the case
for 40 Hz activity, these areas are associated with executive functions such as planning,
voluntary action, and decision-making (Baddeley, 1992; Goleman & Davidson, 1979; Scott
& Schoenberg, 2011; Stuss, 2011).
At the same time, lucid dreaming is accompanied by a clearly REM sleep-like pattern in
lower frequencies. Figure 29.2 illustrates the similarity between ordinary REM-sleep
dreams and lucid ones, as well the clear distinction of both from wakefulness. The
frequency-specific activation underlying non-lucid REM-sleep dreams and lucid dreams
diverges only in the higher frequency bands, beginning around 32 Hz. By contrast,
wakefulness (eyes closed) is characterized by comparatively reduced activity in the lower
frequency bands up to about 6 Hz and a peak in alpha activity between 8 and 12 Hz.
Because we corrected for eye movements, this difference between wakefulness and both
non-lucid REM sleep dreams and lucid dreams cannot be due to oculomotor activity. This
should not be taken to imply that REM sleep is devoid of alpha activity; it means only that
the pattern of alpha activity differs between REM sleep, lucid dreams, and wakefulness.
Finally, aside from the cortical changes observed in lucid dreams, recent studies suggest
that subcortical structures are involved. Evidence for the participation of the cortico-
thalamic-limbic network comes from patients who have suffered a thalamic stroke and
subsequently report emotionally disturbing lucid dreams (Sagnier et al., 2015). The
authors suggest that “this anxious and emotional context probably influenced the
emergence of lucid dreams that could be explained by limbic cortical and subcortical
structures” (p. 771). While this report relies on data from only two patients, it raises the
question of whether thalamic processes may typically serve to suppress lucid dreams or
make their occurrence unlikely. The frequency of autoscopic elements in lucid dreams
additionally suggests an involvement of subcortical structures (Kaliuzhna, Vibert, Grivaz,
& Blanke, 2015). Autoscopy is closely related to out-of-body experiences (OBEs). It refers
to a broad range of visual hallucinations of a bodily image, for example seeing a
doppelgänger or seeing oneself as if from the outside, often from an elevated perspective
(as in OBEs). The autoscopic, visual image may be a more or less accurate duplicate of
one’s real body (Brugger et al., 1997). Although scientific reports are scarce, it appears
as if at least transient dysfunctions in limbic and thalamic structures were involved
(Brugger et al., 1997; Blanke et al., 2004).
Spontaneous Thought, Insight, and Control in Lucid Dreams
Page 15 of 49
PRINTED FROM OXFORD HANDBOOKS ONLINE (www.oxfordhandbooks.com). (c) Oxford University Press, 2015. All Rights
Reserved. Under the terms of the licence agreement, an individual user may print out a PDF of a single chapter of a title in
Oxford Handbooks Online for personal use.
Subscriber: OUP-Reference Gratis Access; date: 14 April 2018
In our study, the coexistence of apparently contrary activation patterns initially led to the
characterization of lucidity as involving a hybrid state between sleep and wakefulness
(Hobson & Voss, 2010, 2011). A different interpretation that we now favor is that
lucidity involves a change in ordinary REM sleep, but without thereby causing awakening
(Czisch et al., 2014; Voss & Hobson, 2015; Voss & Voss, 2014). Here, we want to propose
that this change is best characterized by describing lucidity as arising during a distinct
substage of REM sleep.
Click to view larger
Figure 29.1. Standardized current source density
power (CSD) in a waking participant with eyes closed
(top), during a lucid dream (middle), and during
ordinary REM sleep (bottom). Topographical images
are based on movement-free EEG episodes and were
corrected for eye movements. WEC refers to waking
with eyes closed. Darker color corresponds to higher
40 Hz activity. For a full color picture, see Voss et al.,
2009.
Source: Voss et al. (2009). (See Color Insert)
(p. 394)
Spontaneous Thought, Insight, and Control in Lucid Dreams
Page 16 of 49
PRINTED FROM OXFORD HANDBOOKS ONLINE (www.oxfordhandbooks.com). (c) Oxford University Press, 2015. All Rights
Reserved. Under the terms of the licence agreement, an individual user may print out a PDF of a single chapter of a title in
Oxford Handbooks Online for personal use.
Subscriber: OUP-Reference Gratis Access; date: 14 April 2018
Introducing the distinction
between lucid and non-
lucid REM sleep makes
room for describing lucid
dreaming as a genuine
sleep phenomenon, but
may also help refine sleep-
stage scoring. The
terminology for describing
different sleep stages is
conventional, and scoring
rules are occasionally
adjusted to optimally
reflect new scientific
findings (for a discussion
from a philosophical
perspective, see
Thompson, 2014, 2015a,
2015b; Windt, 2015a, b;
Windt et al., 2016). The
current rules for scoring
non-REM (NREM) sleep
were proposed by the
American Academy of
Sleep Medicine in 2004; they revised the rules proposed by Rechtschaffen and Kales in
1968 (see Silber et al., 2007, for discussion and further references). Different taxonomies
for describing and scoring sleep stages can also coexist. For instance, within the period
stretching from wakefulness via NREM 1 into early NREM 2, 9 EEG substages can be
distinguished, and they bear a complex relationship to different types of mental activity
and subjective judgments of sleep or wakefulness (Stenstrom et al., 2012; for a discussion
of so-called microdreams, or dream-like experiences occurring during sleep
onset, see also Nielsen, 2017). In order to determine the neural correlates of mental
activity during sleep, more fine-grained sleep-stage scoring of this type may be required.
What we are proposing here is a similar refinement of the taxonomy for describing REM
sleep. In the future, the distinction between lucid and non-lucid REM sleep might lead to
distinct scoring criteria. And perhaps, with time, even more fine-grained categories and
scoring criteria can be introduced, describing differences between REM sleep involving
dreams and occasionally dreamless REM sleep, or even different types of dreams arising
in REM sleep. In this process, the distinction between lucid and non-lucid REM sleep is a
first, but important, step. The characterization of lucid dreams as arising during an
altered stage of REM sleep rather than a hybrid state between sleep and wakefulness
also reflects the fact that subjectively, dream lucidity is clearly not a wake-state
Click to view larger
Figure 29.1. Standardized current source density
power (CSD) in a waking participant with eyes closed
(top), during a lucid dream (middle), and during
ordinary REM sleep (bottom). Topographical images
are based on movement-free EEG episodes and were
corrected for eye movements. WEC refers to waking
with eyes closed. Darker color corresponds to higher
40 Hz activity. For a full color picture, see Voss et al.,
2009.
Source: Voss et al. (2009).
(p. 395)
Spontaneous Thought, Insight, and Control in Lucid Dreams
Page 17 of 49
PRINTED FROM OXFORD HANDBOOKS ONLINE (www.oxfordhandbooks.com). (c) Oxford University Press, 2015. All Rights
Reserved. Under the terms of the licence agreement, an individual user may print out a PDF of a single chapter of a title in
Oxford Handbooks Online for personal use.
Subscriber: OUP-Reference Gratis Access; date: 14 April 2018
phenomenon. The following reports following stimulation during REM sleep (for details,
see next section) show this clearly:
Click to view larger
Figure 29.2. EEG Power (POT = scalp potential) in
the analyzed frequencies from 1 to 48 Hz, averaged
over three lucid dreams and for all electrode
recording sites, corrected for eye movements
(Gratton et al. 1983). Dotted line: Waking, eyes
closed (WEC), lying down. Black line: lucid dream
sleep. Broken line: non-lucid REM sleep.
Source: Voss et al. (2009). (See Color Insert)
Click to view larger
Figure 29.2. EEG Power (POT = scalp potential) in
the analyzed frequencies from 1 to 48 Hz, averaged
over three lucid dreams and for all electrode
recording sites, corrected for eye movements
(Gratton et al. 1983). Blue line: Waking, eyes closed
(WEC), lying down. Red line: lucid dream sleep.
Black line: non-lucid REM sleep.
Spontaneous Thought, Insight, and Control in Lucid Dreams
Page 18 of 49
PRINTED FROM OXFORD HANDBOOKS ONLINE (www.oxfordhandbooks.com). (c) Oxford University Press, 2015. All Rights
Reserved. Under the terms of the licence agreement, an individual user may print out a PDF of a single chapter of a title in
Oxford Handbooks Online for personal use.
Subscriber: OUP-Reference Gratis Access; date: 14 April 2018
Example 1: “I saw
myself lying there. I was somehow . . . I looked wounded. I was telling someone
about this while I was lying there, and then I saw myself crying, but not in the
dream, and now there were only the other people there and I told them how this
happened. And that’s when I seem to have noticed that I was dreaming, in the
dream.”
Example 2: “I was sitting at my computer with my grandfather and I was
explaining something to him and then I suddenly thought, ‘whoops, am I
dreaming? If so, I could just get up and walk around,’ and so that’s what I did. I
walked around for about 20 seconds. I didn’t do anything else. The floor was
colored, like a mosaic. I walked through the house, went outside, and then I
noticed that all of the floors were somehow paved with mosaic stones.”
The bizarreness and incoherence of these reports illustrate, we think, the degree to
which lucidity (and its precursors) involves a change in ordinary REM sleep, but without
thereby causing awakening. The investigation of the transition between non-lucid and
lucid dreaming can thus help determine the extent to which levels of awareness that have
traditionally been assumed to be restricted to wakefulness are in fact compatible with
sleep, but also highlights the inherently dreamlike character of lucid dreams, which is so
prominent in both of these reports. The compatibility of insight and otherwise dreamlike
conscious thought, in particular, is important from an empirical perspective, but also
challenges the commonly accepted taxonomy of mental states by blurring the conceptual
distinction between sleep and wakefulness.
Induction of Lucid Dreams Through
Frontotemporal Low Current Electrical
Stimulation at 40 Hz
An important question that is associated with investigating the neural correlates of
lucidity is how to increase the frequency of lucid dreams, especially under the systematic
and controlled conditions of the sleep laboratory. A related question concerns the causally
enabling conditions for lucidity to arise. After numerous failed attempts to induce lucidity
with the help of light or acoustic signals (which had low success rates at best; see
Stumbrys et al., 2012), we were able to use electrical stimulation at 40 Hz during REM
sleep to induce changes in experience of the type normally associated with spontaneous
lucid dreaming—almost as if stimulation were pushing initially non-lucid dreams in the
direction of lucidity (Voss et al., 2014). We used the method of transcranial alternating
current stimulation (tACS). In line with evidence from spontaneous lucid dreams, we
stimulated bilaterally over frontotemporal brain areas at several low frequencies (see
gray rectangles in Figure 29.3 A and B). The electric current had been determined based
Source: Voss et al. (2009).
8
Spontaneous Thought, Insight, and Control in Lucid Dreams
Page 19 of 49
PRINTED FROM OXFORD HANDBOOKS ONLINE (www.oxfordhandbooks.com). (c) Oxford University Press, 2015. All Rights
Reserved. Under the terms of the licence agreement, an individual user may print out a PDF of a single chapter of a title in
Oxford Handbooks Online for personal use.
Subscriber: OUP-Reference Gratis Access; date: 14 April 2018
on pilot studies so as to minimize the likelihood of awakening during stimulation (250
µA). We also applied a local analgesic to the stimulated patches of skin. As noted
earlier, all of our participants reported having no prior experience with lucid dreams.
In this comprehensive double-blind study, we tested six different conditions, including
repeated measurement (stimulation at 2 Hz, 6 Hz, 12 Hz, 70 Hz, 100 Hz, contrasted with
pseudostimulation/sham). Our participants spent up to four non-consecutive nights in the
laboratory; stimulation was conducted during REM sleep, with the first stimulation
beginning after 3 a.m. The duration of stimulation was 30 seconds and participants were
awakened immediately afterward. With the help of specific algorithms (Voss et al., 2014),
we filtered the stimulation signal out of the EEG data in order to ensure that stimulation
had not led to an interruption of REM sleep. During each experimental night we
alternated between two conditions (e.g., between 2 Hz and 40 Hz or between 12 Hz and
70 Hz, with a balanced design for participants and nights).
Click to view larger
(p. 396)
Spontaneous Thought, Insight, and Control in Lucid Dreams
Page 20 of 49
PRINTED FROM OXFORD HANDBOOKS ONLINE (www.oxfordhandbooks.com). (c) Oxford University Press, 2015. All Rights
Reserved. Under the terms of the licence agreement, an individual user may print out a PDF of a single chapter of a title in
Oxford Handbooks Online for personal use.
Subscriber: OUP-Reference Gratis Access; date: 14 April 2018
Figure 29.3. Effect of transcranial alternating
current stimulation (tACS) on EEG gamma power
(37–43 Hz). tACS electrodes were placed bilaterally
at frontal and temporal positions (black rectangles)
and current was flowing back and forth between
these electrodes. EEG electrode placements are
indicated as dark dots. (A) Stimulation with 6 Hz
resulted in no change in lower gamma activity
around 40 Hz (37–43 Hz). (B) Stimulation with 40 Hz
led to a strong increase in lower gamma activity
around 40 Hz. (C) Grand average Fast Fourier
Transform (FFT) power ratios of activity during
versus activity prior to stimulation for the 6-Hz
stimulation condition. Gray shading represents mean
values ± 2 standard errors (s.e.). Any excursions
outside of this range would be considered significant
at least at the p < .05 level. However, with 6 Hz, we
see no significant stimulation-induced increase in 6
Hz activity. (D) Grand average FFT power ratios of
activity during versus activity prior to stimulation for
the 40-Hz stimulation condition. Grey shading
represents mean values ± 2 standard errors (s.e.).
Note that lucid dreams (gray line) are accompanied
by a significantly larger increase in the 40 Hz
frequency band than non-lucid dreams (black line)
(independent two-sided t tests between lucid and
non-lucid dreams during stimulation with 40 Hz:
t = 5.01, df = 35, p < 0.001).
Source: Voss & Hobson (2015). (See Color Insert)
Click to view larger
40Hz
Spontaneous Thought, Insight, and Control in Lucid Dreams
Page 21 of 49
PRINTED FROM OXFORD HANDBOOKS ONLINE (www.oxfordhandbooks.com). (c) Oxford University Press, 2015. All Rights
Reserved. Under the terms of the licence agreement, an individual user may print out a PDF of a single chapter of a title in
Oxford Handbooks Online for personal use.
Subscriber: OUP-Reference Gratis Access; date: 14 April 2018
The only stimulation
frequencies to induce
changes in the lower
gamma band were 25 Hz
and 40 Hz. Figure 29.3
illustrates the effect of
stimulation at 6 Hz (no
change in the theta
frequency band or
any other frequency) and
40 Hz (strong increase in
the lower gamma
frequency band).
Importantly, even 40 Hz
stimulation did not always
lead to subjective reports
of lucidity. When
participants did report a
lucid dream after
awakening, however,
activity in the lower
gamma frequency band
was clearly elevated. This
leads us to assume that, on the one hand, activity in the lower gamma band is necessary
(but not sufficient) to induce lucidity, and on the other hand, that dream lucidity further
increases activity in this frequency band.
Difficulties and Limitations
As mentioned earlier, the frequency of spontaneous REM-initiated lucid dreams is very
low in adults (Voss et al., 2009; Voss et al., 2013), and somewhat paradoxically, being
asked to produce a lucid dream in a sleep laboratory may further reduce the likelihood of
success. The following examples from trained lucid dreamers illustrate this point:
Example 3: “It is not easy to become lucid in a dream or to stay lucid. Lucidity is
fragile and basically, it is always about keeping the right balance between control
and looseness.” (27-year-old female)
Example 4: “For me, a lucid dream is always an exceptionally exciting
experience. . . . This condition feels like a brain battle between maintaining the
dream scenery and waking up. In these short periods of clarity the acting dream
body and the real body that lies in bed exist simultaneously and it costs great
Figure 29.3. Effect of transcranial alternating
current stimulation (tACS) on EEG gamma power
(37–43 Hz). tACS electrodes were placed bilaterally
at frontal and temporal positions (black rectangles)
and current was flowing back and forth between
these electrodes. EEG electrode placements are
indicated as dark dots. (A) Stimulation with 6 Hz
resulted in no change in lower gamma activity
around 40 Hz (37–43 Hz). (B) Stimulation with 40 Hz
led to a strong increase in lower gamma activity
around 40 Hz. (C) Grand average Fast Fourier
Transform (FFT) power ratios of activity during
versus activity prior to stimulation for the 6-Hz
stimulation condition. Yellow shading represents
mean values ± 2 standard errors (s.e.). Any
excursions outside of this range would be considered
significant at least at the p < .05 level. However, with
6 Hz, we see no significant stimulation-induced
increase in 6 Hz activity. Grand average FFT power
ratios of activity during versus activity prior to
stimulation for the 40-Hz stimulation condition.
Yellow shading represents mean values ± 2 standard
errors (s.e.). Note that lucid dreams (red line) are
accompanied by a significantly larger increase in the
40 Hz frequency band than non-lucid dreams (blue
line) (independent two-sided t tests between lucid
and non-lucid dreams during stimulation with 40 Hz:
t = 5.01, df = 35, p < 0.001).
Source: Voss & Hobson (2015).
40Hz
(p. 397)
Spontaneous Thought, Insight, and Control in Lucid Dreams
Page 22 of 49
PRINTED FROM OXFORD HANDBOOKS ONLINE (www.oxfordhandbooks.com). (c) Oxford University Press, 2015. All Rights
Reserved. Under the terms of the licence agreement, an individual user may print out a PDF of a single chapter of a title in
Oxford Handbooks Online for personal use.
Subscriber: OUP-Reference Gratis Access; date: 14 April 2018
effort and concentration to keep up the balance between the two.” (22-year-old
female)
The possibility of inducing lucid dreams through electrical stimulation of the brain
constitutes a new and promising method to increase the frequency of lucidity under
laboratory conditions. However, this method is quite demanding, and at this point, we
must consider it possible that electrically induced lucid dreams differ from spontaneous
ones. Dodet et al. (2014) have observed that narcolepsy patients often report lucid
dreams and propose to use these patients as subjects and thereby bypass the recruitment
problem that hampers many lucid dream studies. Here, too, the question is how similar
the lucid dreams of narcolepsy patients are to those occurring independently of sleep
disturbances.
Another important question refers to causality. We found that lucidity can be triggered
through the external application of a 40 Hz current, but also that stimulation with 40 Hz
does not always lead to a measurable lucid dream. Our induction study was very
elaborate, and we tested a large number of subjects across several nights. Yet while the
effect was statistically significant, the average questionnaire scores suggest that we
achieved only small changes in absolute terms. Also, while stimulation with 40 Hz led to
an increase in lower gamma band activity, this increase was much greater when it was
accompanied by a lucid dream. It is thus possible that the 40 Hz activity we managed to
induce experimentally was insufficient to initiate lucidity. This once more raises the
question of the predictability and scoring of lucid dreams. Under what conditions is it
justified to score a period of REM sleep as lucid when the frontal lobe is activated in the
40 Hz frequency band? How long and how intense must frontal 40 Hz activity be to lead
to a remembered lucid dream? In light of our earlier suggestion of introducing lucid REM
sleep as a substage of REM sleep, it will be imperative to eventually answer these
questions, and we hope that future studies will help make progress toward doing so.
Insight, Control, and Spontaneous Cognitive
Processing in Lucid Dreams
Based on our review of some of the main scientific findings on dream lucidity, we can now
return to our original question: What role does spontaneous cognitive processing play in
lucid dreams? Are lucid dreams, like non-lucid ones, still paradigmatic cases of mind-
wandering? Or does realizing that one is dreaming, coupled with the ability to control the
dream, effect such a radical change in overall processing that the analogy with wake-
state mind-wandering is broken? We can begin to tackle these questions by asking about
the extent and limits of lucid dream control. As noted earlier, this also will help identify
those aspects of dreaming that are most interesting for the investigation of spontaneous
cognitive processes.
Spontaneous Thought, Insight, and Control in Lucid Dreams
Page 23 of 49
PRINTED FROM OXFORD HANDBOOKS ONLINE (www.oxfordhandbooks.com). (c) Oxford University Press, 2015. All Rights
Reserved. Under the terms of the licence agreement, an individual user may print out a PDF of a single chapter of a title in
Oxford Handbooks Online for personal use.
Subscriber: OUP-Reference Gratis Access; date: 14 April 2018
While the extent to which skilled lucid dreamers can control not just their own actions
but also effect changes in the dream environment is impressive, it seems that even in
systematically performed lucid dream experiments involving signal-verified lucid dreams
in the laboratory, there is still much room for spontaneity and surprise. To begin with, the
success rate for actually carrying out one’s waking intentions in a lucid dream is
comparatively small. According to one study, lucid dreamers remembered their waking
intentions, for instance to perform a particular dream experiment, only about half the
time, and less than half of these remembered intentions were successfully carried out in
dreams (Stumbrys, Erlacher, Johnson, & Schredl, 2014). This suggests that while
the contents of lucid dreams can in principle be brought under deliberate control, they
mostly unfold spontaneously, rather than according to waking intentions.
This appears to be reflected in the subjective experience of dream lucidity. Dresler and
colleagues (2013) asked experienced lucid dreamers to assess the level of volition in lucid
dreams, non-lucid dreams, and wakefulness. They found that self-determination, or the
ability to act freely according to one’s will, obtained higher ratings for lucid dreams and
wakefulness than for non-lucid dreams. Planning ability received high ratings for
wakefulness but low ones for lucid and non-lucid dreams, and intention enactment, or
assessing how promptly intentions are executed, was highest in lucid dreams and lower
but comparable in wakefulness and non-lucid dreaming. This seems to suggest that lucid
dreamers are aware of their ability to control their dreams independently of real-world
constraints, but mostly enact spontaneous intentions rather than ones formed in
wakefulness. In fact, they may even have the experience that their ability to act upon
long-standing, waking intentions is diminished in lucid dreams as compared to
wakefulness.
A slightly stronger point would be that the association between lucid dream control and
spontaneous cognitive processes is not just statistically frequent, but systematic.
Experienced lucid dreamers often say that lucid dreaming involves a kind of balancing act
between active participation and critical, reflective distance (LaBerge, 1985, pp. 104–
108; see also Examples 3 and 4, earlier in this chapter). The deliberate suspension of
disbelief may even be used to facilitate dream control; for instance, treating dream
characters as if they were real may help “fill in” the overall situation and stabilize the
dream by making it feel more real (Schatzman et al., 1988, pp. 171–172). Even when
lucid dreamers successfully act upon their waking intentions, the result is often not
exactly what they were expecting. The following example shows that even high levels of
insight and control are compatible with spontaneous, subjectively unexpected, and
surprising dream contents:
Example 5: “I am on a large, cobbled square in a fantastically beautiful port city
that reminds me of some of the locations from Hayo Mizayaki’s Howl’s Moving
Castle. Sky and water are shining in a bright azure, so that the horizon is barely
visible; there is not a single cloud in sight. ‘Too bad that this isn’t a lucid dream,’ I
(p. 398)
Spontaneous Thought, Insight, and Control in Lucid Dreams
Page 24 of 49
PRINTED FROM OXFORD HANDBOOKS ONLINE (www.oxfordhandbooks.com). (c) Oxford University Press, 2015. All Rights
Reserved. Under the terms of the licence agreement, an individual user may print out a PDF of a single chapter of a title in
Oxford Handbooks Online for personal use.
Subscriber: OUP-Reference Gratis Access; date: 14 April 2018
think, but then in the very next moment I hear myself say, internally: ‘Well, then
just turn it into one!’
At that same moment, I become lucid and my visual field expands rapidly.
Everything looks much clearer and more sharply defined. I am immediately aware
that I am now able to do anything imaginable, no matter how absurd or surreal,
and I feel immense euphoria. I pull a silver hand mirror out of a pants pocket that
is comparatively much too small and check my eye movements. Left, right, left,
right. My reflection in the dream mirror does not quite correspond to my waking
one, but I recognize myself nonetheless.
I place the mirror back in my pocket and use both feet to push away from the
ground. Flying has always been my first intention when I became lucid. I circle
above the peer for a few rounds, together with the seagulls, my hair blowing in
the soft ocean breeze. An indescribable sense of freedom. If I now really have the
opportunity to do anything I like, I should seize it, I think. I decide to look for
Albert Einstein. I continue to fly, hoping to see him from above, but then realize
that this is an inefficient method and decide to land. I have another idea.
Resolutely, I walk towards the next-best hotdog cart, traditionally painted with red
and white stripes. The friendly vendor is about to start praising his hotdogs, but I
am faster and wipe over his face with my right hand. Again, left, right, left, right.
And as his red-cheeked, moon-shaped face pales with every wipe, the famous
features of Albert Einstein slowly take its place; in black and white. My plan has
worked.
I introduce myself and ask if he can explain the world formula to me. Out of
nowhere, a piece of paper appears in his right hand and a pen in his left. It’s really
simple, he explains, and begins to write red numbers on the piece of paper. He
starts with 532 and subtracts another number, then divides by another one. I don’t
completely follow the point of this calculation; to the contrary, it seems to be
completely arbitrary. But against my expectations, he continues to perform simple
calculations with relatively small numbers. Not a single Greek letter appears.
When the whole page has been filled with writing, I wake up. I can’t remember
the result of the calculation but it wasn’t 42.” (23-year-old-female, mathematics
student)
As this report was taken from a home diary, we have no way of knowing which sleep stage
the dream occurred in, whether this was a WILD or a REM-initiated lucid dream, and
whether it was reported immediately upon awakening. Judging from the wording,
it does seem heavily edited. But if we take the report at face value, then it nicely
illustrates that even successful dream control is the result of interacting with the dream
environment: control is a matter of modulating the dream as it unfolds, rather than
forcing it in another direction entirely. Control and insight are also compatible with the
9
(p. 399)
Spontaneous Thought, Insight, and Control in Lucid Dreams
Page 25 of 49
PRINTED FROM OXFORD HANDBOOKS ONLINE (www.oxfordhandbooks.com). (c) Oxford University Press, 2015. All Rights
Reserved. Under the terms of the licence agreement, an individual user may print out a PDF of a single chapter of a title in
Oxford Handbooks Online for personal use.
Subscriber: OUP-Reference Gratis Access; date: 14 April 2018
subjective sense of spontaneity. For the same reason, some level of dream control is
important to counteract the loss of lucidity itself; if one engages too fully with the dream,
one too easily forgets that it is just, after all, a dream (Brooks & Vogelsong, 1999).
The sense of effort involved in the maintenance of dream lucidity is nicely complemented
by the importance of dissociative phenomena and derealization, which, as mentioned
earlier, are hallmarks of lucidity. Control may also precede lucid insight, with dreamers
carrying out their waking intentions, for instance to conduct a specific dream experiment,
without having explicitly realized that they are now dreaming. Sometimes, this type of
lucid dream behavior then leads to the cognitive realization that this is actually a dream
(Brooks & Vogelsong, 2000). This complex relationship between the different factors
characterizing fully lucid dreams means that lucid dreams are a rich opportunity for
investigating the interplay between deliberate control and lower-level, automatic
cognitive processes of the type underlying the process of dream formation. This is true
not only theoretically and scientifically, but also subjectively. As illustrated by the
following report by Frederik van Eeden, lucid control dreams are an opportunity for
introspectively observing the interplay of these factors as the dream unfolds—and we
suspect that the element of surprise accounts for a large part of the fascination with lucid
dreaming:
Example 6: “On Sept. 9, 1904, I dreamt that I stood at a table before a window. On
the table were different objects. I was perfectly well aware that I was dreaming
and I considered what sorts of experiments I could make. I began by trying to
break glass, by beating it with a stone. I put a small tablet of glass on two stones
and struck it with another stone. Yet it would not break. Then I took a fine claret-
glass from the table and struck it with my fist, with all my might, at the same time
reflecting how dangerous it would be to do this in waking life; yet the glass
remained whole. But lo! when I looked at it again after some time, it was broken.
It broke all right, but a little too late, like an actor who misses his cue. This gave
me a very curious impression of being in a fake-world, cleverly imitated, but with
small failures. I took the broken glass and threw it out of the window, in order to
observe whether I could hear the tinkling. I heard the noise all right and I even
saw two dogs run away from it quite naturally. I thought what a good imitation this
comedy-world was. Then I saw a decanter with claret and tasted it, and noted with
perfect clearness of mind: ‘Well, we can also have voluntary impressions of taste
in this dream-world; this has quite the taste of wine.’ ” (van Eeden, 1913)
The spontaneous and often surprising aspects of lucid dreaming also facilitate the types
of naïve-realistic beliefs in the reality of dream events that are normally thought to
characterize only non-lucid dreams. So-called lucidity lapses, or instances in which lucid
dreamers fail to realize the full consequences of the fact that they are now dreaming, can
be fairly localized and often seem to reflect some of our most deeply ingrained beliefs and
expectations. Often, they arise with respect to events that would be dangerous in waking
life (such as cutting oneself with a knife or jumping off a cliff), and they also often have a
10
Spontaneous Thought, Insight, and Control in Lucid Dreams
Page 26 of 49
PRINTED FROM OXFORD HANDBOOKS ONLINE (www.oxfordhandbooks.com). (c) Oxford University Press, 2015. All Rights
Reserved. Under the terms of the licence agreement, an individual user may print out a PDF of a single chapter of a title in
Oxford Handbooks Online for personal use.
Subscriber: OUP-Reference Gratis Access; date: 14 April 2018
social component, such as feeling embarrassed, being convinced that another dream
character is a real person, or even thinking that one is sharing the dream with someone
else (Green & McCreery, 1994, pp. 28–29; Levitan, 1994). Some lucidity lapses appear to
involve spontaneous thought in the narrow, phenomenological sense of experiencing
oneself as a thinker of thoughts introduced in the first section of this chapter. To the
extent that these spontaneous thoughts are prompted by the experiential character of the
dream (e.g., the seemingly realistic behavior of other dream characters), these are
examples of how spontaneous, conscious thought can be shaped by lower-level imagistic
cognition.
Do lucidity lapses mean that thinking even in lucid dreams is marked by the same
cognitive deficiencies as in non-lucid dreams and should be set apart from waking
thought? Not necessarily. It is noteworthy that in virtual reality experiments, social
interactions and potentially threatening situations, such as walking to the edge of a cliff,
enhance the subjective feeling of presence (Sanchez-Vives & Slater, 2005; Slater, 2009).
Social interactions, in particular, seem to be even more important for generating the
illusion of presence in virtual environments than perceptual realism (Slater, 2009)—and
again, note that this is true for healthy participants who are awake and fully aware that
what they are experiencing is just a high-tech simulation, not reality. For instance,
participants with a fear of speaking in public feel similarly nervous when asked to
speak in front of a group of virtual characters (Sanchez-Vives & Slater, 2005). This
suggests that in both sleep and wakefulness, insight is compatible with the subjective
feeling of presence, and often with behavioral and emotional reactions that would be
appropriate if the events in question were occurring in the real world, and not just in a
virtual or dreamed one. So-called lucidity lapses therefore do not appear to be unique to
lucid dreams or to be confined to sleep. This leads to an interesting conceptual point:
Whereas the occurrence of lucid insight in sleep puts pressure on attempts to cast
metacognitive awareness, insight, and critical self-reflection as strictly “wake-like” forms
of thinking, the similarity between lucidity lapses and reactions prompted by virtual
environments in healthy, waking participants raises doubts about the alleged deficiency
underlying “dreamlike” conscious thought. To be clear, we are not denying that such
differences between thinking in dreams and in wakefulness exist—we are just suggesting
that they are less clear-cut than is often assumed.
Lucidity lapses are also interesting because they may indicate which types of dream
content fit our phenomenological notion of spontaneous cognitive processing. Again,
social interactions between the dream self and other dream characters in lucid dreams
are a nice example. The status of dream characters that are experienced as distinct from
the self has long been a source of fascination. Social imagery plays an important role in
dreams, with social interactions being even more frequent in dreams than in waking life
(McNamara, McLaren, Smith, Brown, & Stickgold 2005). Non-self dream characters are
rarely bizarre and are typically experienced as highly realistic. They are also often
experienced as having a mind of their own, and dreamers frequently ascribe thoughts,
feelings, and intentions to other dream characters (Kahn & Hobson, 2005b). Recently, the
wealth of social imagery in dreams has even been suggested to shed light on the
(p. 400)
Spontaneous Thought, Insight, and Control in Lucid Dreams
Page 27 of 49
PRINTED FROM OXFORD HANDBOOKS ONLINE (www.oxfordhandbooks.com). (c) Oxford University Press, 2015. All Rights
Reserved. Under the terms of the licence agreement, an individual user may print out a PDF of a single chapter of a title in
Oxford Handbooks Online for personal use.
Subscriber: OUP-Reference Gratis Access; date: 14 April 2018
evolutionary function of dreaming (Revonsuo et al., 2015a). Social interactions in lucid
dreams might thus be particularly interesting for investigating the interplay between
spontaneous contents and deliberate control. A prediction would be that the ability to
control the actions of a non-self dream character should be inversely related to the
degree of experienced spontaneity and perhaps realism. If another dream character’s
actions can be controlled, we would expect this character to be experienced as not quite
distinct from the self, whereas experienced difficulties in controlling a non-self dream
character might prompt lucidity lapses, such as believing that the dream character is
actually a real person.
This prediction appears to be supported by existing studies of social interaction in lucid
dreams. Stumbrys et al. (2011) investigated the abilities of dream characters to solve
simple mathematical problems in lucid dreams. Overall, the dream characters performed
quite poorly and their answers were comparable to those of primary school students. For
present purposes, however, how the dream characters reacted to these questions is more
interesting. One dream report described that when asked to calculate 18 minus 6, the
dream character refused, complaining that the question was much too private—a
response that the dreamer found both baffling and inspiring. Two other reports described
that dream characters, when confronted with mathematical problems, ran away or even
started to cry. Other times, the dream characters came up with the correct answers, even
though the dreamer had anticipated a false one. In these cases, the answers given by
non-self dream characters were not directly accessible to the dreamers—they were
experienced as surprising and as distinct from their own thought processes.
In another online experiment, Schmidt et al. (2014) instructed lucid dreamers to ask
another dream character to guess how many fingers they were holding up behind their
backs, or, in reverse, to themselves attempt to guess how many fingers other dream
characters were holding up behind their backs. Generally, the success rate was higher
than one would expect in waking participants engaging in real social interactions,
indicating, not very surprisingly, that non-self dream characters are incompletely
differentiated from the dream self. But the most important factor predicting the outcome
of the dream experiment were the dreamers’ own expectations before the experiment. If
dreamers thought they would be able to “guess” the number of fingers other dream
characters were holding up behind their backs, they were much more likely to be able to
do so than if they expected this to be difficult. Even subjectively surprising dream
contents may thus be biased by the dreamer’s own unconscious expectations.
Windt et al. (2014) attempted to investigate the relationship between control and non-self
dream characters in lucid dreams in a slightly different manner. Our question was
whether it would be possible, in a lucid control dream, to tickle oneself or to be tickled by
another dream character. This is interesting because in wakefulness, it is
impossible to tickle oneself. Put simply, the sensory outcome of self-initiated actions is
expected, and so it is attenuated, preventing self-induced tickles from feeling ticklish.
There are, however, exceptions: schizophrenic subjects are able to tickle themselves
(Blakemore, Wolpert, & Frith, 2000), as are healthy participants who have just been
(p. 401)
Spontaneous Thought, Insight, and Control in Lucid Dreams
Page 28 of 49
PRINTED FROM OXFORD HANDBOOKS ONLINE (www.oxfordhandbooks.com). (c) Oxford University Press, 2015. All Rights
Reserved. Under the terms of the licence agreement, an individual user may print out a PDF of a single chapter of a title in
Oxford Handbooks Online for personal use.
Subscriber: OUP-Reference Gratis Access; date: 14 April 2018
awakened from REM sleep and say they have been dreaming (Blagrove, Blakemore, &
Thayer, 2006). In both cases, the lack of attenuation for the sensory consequences of self-
initiated actions is likely due to disturbances in agency and self-other distinctions. In our
study, we found that at least in the context of lucid control dreams, the distinction
between tickling oneself and being tickled by another dream character was obliterated.
This makes sense: Directing the actions of another dream character involves a
sophisticated form of dream control, and often, the participants in this online study
reported that they did not succeed. Yet when they did, the tickles administered by other
dream characters tended to not feel very ticklish—they felt more like tickling oneself,
both in lucid dreams and in wakefulness. Control, expectation, and experienced self-other
distinctions are closely linked, and this relationship appears to be reflected on the level of
phenomenal experience in lucid control dreams as well.
Expectation can also blur the distinction between lucid dream control and standard, non-
lucid dreaming in another way. This is connected to the narrative structure of dreams.
Many authors have remarked on the tendency of dreams to fluidly respond to dreamers’
thoughts and concerns—sometimes even in a way that appears to preempt explicit insight
into the fact that they are now dreaming. Some have thought that this means dreams are
the product of unconscious authorship (McGinn, 2009); others have emphasized the
similarity between dreaming and confabulation (Hobson, 1999). We want to suggest a
more neutral reading, in which there is no sharp distinction or strict cutoff line between
the lower-level imagistic processes underlying dream formation and higher-level,
conceptually mediated insight and control, as in lucid dreams. These are simply different
expressions of the same underlying process, though at different levels. As Pace-Schott
puts it, “dream hallucinosis itself may generate low-level narrative coherence by
associative processes in which images evoke related images . . . that are successfully
woven together by this putative tendency to organize experience as a story” (2013, p. 2).
This does not happen deliberately, but seemingly automatically—and while the factors
determining the success of attempts to induce lucid control dreams are unknown, this
might be why, as remarked earlier, suspending disbelief and “going with the flow” is often
an effective way of indirectly exercising lucid dream control. Put differently, control in the
context of lucid dreams may just be the special case in which expectations are
deliberately used to nudge the largely spontaneous process of dream formation in the
desired direction. Successful dream control may thus result when conscious and explicit
intentions are temporarily aligned with the non-conscious processes and implicit
expectations that drive the largely spontaneous process of dream formation. This
comparatively tighter coupling between conscious thought and the ongoing flow of dream
events would explain why the balance between critical distance and active participation
in lucid dreams is so hard to maintain, but also why dream thinking is easily captured or
even corrupted (Windt, 2015a) by dream imagery, resulting in lucidity lapses. For the
same reason, this close connection between expectation and dream imagery production
can also prevent explicit lucid insight. Take the following example:
Spontaneous Thought, Insight, and Control in Lucid Dreams
Page 29 of 49
PRINTED FROM OXFORD HANDBOOKS ONLINE (www.oxfordhandbooks.com). (c) Oxford University Press, 2015. All Rights
Reserved. Under the terms of the licence agreement, an individual user may print out a PDF of a single chapter of a title in
Oxford Handbooks Online for personal use.
Subscriber: OUP-Reference Gratis Access; date: 14 April 2018
Example 7: “I noticed that immediately in front of me, a house appeared to be
standing on its head, and concluded that I must be dreaming. But then I noticed
that I was wearing glasses, and immediately thought that the reversed visual
effect must be caused by the glasses. In order to ascertain whether this was the
case, I removed the glasses, whereupon I saw the house in its correct position.
This led me to falsely conclude that I was awake after all.” (Tholey & Utecht,
1987, p. 88; translation by J. W.)
What about the occurrence of lucidity itself? To what extent should we regard lucid
insight into the fact that one is now dreaming as a spontaneous thought process, and to
what extent is this insight itself controllable? To begin with, while lucid dreaming is a
learnable skill, it is difficult to master, and perhaps increasingly so in adulthood. As
mentioned earlier, the comparatively high frequency of lucidity in childhood and
adolescence may be related to brain maturation, especially as the peak frequency in lucid
dreaming coincides with the final stages of frontal lobe myelination and at a time of
synapse expansion and dendritic growth. As Voss and Hobson (2014) point out, these
natural processes might facilitate the activation of frontal areas in REM sleep in
adolescence and thus lead to dream lucidity. In addition, adolescence is associated
with changes in the timing of sleep and a maturation of circadian processes.
Adolescents require as much sleep as pre-adolescents, but their sleep patterns undergo a
phase-delay, leading adolescents to stay up later and, in association with early school
times, to experience an increase in daytime sleepiness (Wolfson & Carskadon, 2003). This
might be another factor that facilitates the occurrence of lucidity in adolescent sleep—
especially as lucidity tends to occur in the second half of the night and especially toward
morning or during morning naps (LaBerge, Phillips, & Levitan, 1994) and in our
experience is more easily initiated from wakefulness than from within the dream state
(but see Stumbrys et al., 2012). The association between spontaneous lucidity and shifts
in circadian rhythms also fits well with our earlier observation of lucidity being a
transitional state between sleep and wakefulness, as well as with anecdotal reports
describing lucidity as a balancing act between non-lucid dreaming and awakening. In this
reading, lucidity, at least when occurring in adolescence, can be described as a
spontaneous glitch, a byproduct of brain maturation and associated shifts in circadian
processes underlying the timing of sleep.
A related point is that the timing and duration of lucid dreams are largely dependent on
the occurrence and duration of REM phases. Lucid dreams can be voluntarily terminated:
Because of the correspondence between real-eye and dream-eye movements, lucid
dreamers can wake themselves up by fixing their gaze on something and thus
interrupting the rapid eye movements (LaBerge, 1985). But lucid dreams cannot be
prolonged indefinitely, and while lucid dreams occurring at home may be longer and more
easily maintained, the majority of lucid dreams occurring in the laboratory are very short,
lasting around two minutes (Voss et al., 2013).
(p. 402)
Spontaneous Thought, Insight, and Control in Lucid Dreams
Page 30 of 49
PRINTED FROM OXFORD HANDBOOKS ONLINE (www.oxfordhandbooks.com). (c) Oxford University Press, 2015. All Rights
Reserved. Under the terms of the licence agreement, an individual user may print out a PDF of a single chapter of a title in
Oxford Handbooks Online for personal use.
Subscriber: OUP-Reference Gratis Access; date: 14 April 2018
Tellingly, even experienced lucid dreamers seem unable to suppress visual imagery for
prolonged periods, or at least not without waking themselves up. At the same time, other
types of imagery that are normally rare in dreams (for instance, smell or taste) can,
apparently, be induced successfully (Worsley, 1988; see also Example 6). Visual imagery,
however, may be so central to the process of dream generation that its suppression leads
to a disruption of REM sleep. All of this suggests that lucidity is, for the most part, a
spontaneously occurring cognitive process: The contents of lucid dreams can, to an
extent, be deliberately controlled, lucid dreams can often be terminated at will (though it
would seem that more often, they end spontaneously), and induction techniques can
facilitate the onset of lucidity. But voluntary control involved in initiating and maintaining
lucidity often fails and might exert a mostly modulatory influence.
An important question in this context is whether the core feature of lucidity, namely the
cognitive realization that one is now dreaming, is itself the outcome of a process of
deliberate reasoning or occurs spontaneously, as a form of intuitive insight, rather than as
an intellectual achievement. Here, it would seem that both variants exist—sometimes,
lucid dreamers engage in a complex line of reasoning to conclude that they are now
dreaming, whereas other times, the insight that they are dreaming seemingly comes out
of nowhere; dreamers just know that this is a dream (see, for instance, Examples 1 and 2).
We might say that in these cases, lucid insight results from a spontaneously occurring
metacognitive feeling (Dokic, 2012), rather than from an explicit and deliberate attempt
at cognitive evaluation. This feeling—, for instance an impression that everything has
taken on a dreamlike character,—then acts as a precursor to the explicit and conceptually
mediated thought that this is a dream. According to one study, the onset of lucidity was
associated with a “dreamlike sense” in 48%–67% of cases (Gackenbach, 1988, p. 193),
whereas the recognition of an incongruent element triggered lucidity in only 11%–19%.
The situation is further complicated by the fact that experienced lucid dreamers may
recognize the dream state by sheer familiarity; they may just know they are dreaming
without ever conceptualizing or explicitly thinking about this fact at all. Such cases of
“tacit” lucidity may be extremely hard to detect in dream reports, and subjects
themselves may even be uncertain as to whether or not a given dream of their own was
lucid (Brooks & Vogelsong, 1999, pp. 26–31; LaBerge & DeGracia, 2000; Worsley, 1988, p.
341). Perhaps, tacit lucidity can be seen as the outcome of unconscious goal
representations (Bargh, Gollwitzer, Lee-Chai, Barndollar, & Trötschel, 2001), for instance
of the intention to become lucid. The Einstein dream cited earlier (Example 5) seems to
be a good example of tacit lucidity of this type preceding explicit insight. The report’s
wording suggests that in this case, the onset of lucidity itself can be experienced as
something spontaneous, as an automatic process: the dreamer hears herself say, “this is a
dream,” rather than experiencing this insight as the outcome of a conscious and
deliberate reasoning process.
If insight into the fact that one is now dreaming can arise spontaneously, seemingly
independently of rational thought, this brings with it an interesting problem:
Spontaneous metacognitive insight of this type does not seem categorically different from
cases in which dreamers subjectively just know that they are now awake. The explicit
(p. 403)
Spontaneous Thought, Insight, and Control in Lucid Dreams
Page 31 of 49
PRINTED FROM OXFORD HANDBOOKS ONLINE (www.oxfordhandbooks.com). (c) Oxford University Press, 2015. All Rights
Reserved. Under the terms of the licence agreement, an individual user may print out a PDF of a single chapter of a title in
Oxford Handbooks Online for personal use.
Subscriber: OUP-Reference Gratis Access; date: 14 April 2018
belief that one is awake, even though one is in fact dreaming, is the hallmark of false
awakenings and pre-lucid dreams. Again, two variants exist, which complement the ways
in which lucidity can be attained (see Windt, 2015a, Chapter 10, for details). First,
dreamers can conclude that they are awake as a result of faulty reasoning. For instance,
they might try to engage in reality testing by attempting to fly and then conclude that
they are awake because they have floated off the ground. Second, dreamers might just
know they are awake, and this conviction may be driven by the seemingly realistic quality
of dream imagery that subjectively leaves little room for conscious doubts. These cases of
just knowing that one is awake seem analogous to cases of just knowing that one is now
dreaming: Both involve explicit beliefs about one’s current conscious state and both are
driven by lower-level cognitive processing, rather than by conscious self-reflection and
reasoning. From an epistemological perspective, this is quite worrisome: Despite having
opposite truth values and different content (I am dreaming versus I am awake, where in
reality one is dreaming), both result from the same type of metacognitive processing, and
on the level of phenomenal experience, they carry with them the same subjective
conviction. The experience of certainty and of knowing, far from being a sure guide to
truth, can be deeply deceptive (cf. Metzinger & Windt, 2014, 2015). For now, another
point is more important: Whether or not the dreamer hits on the correct conclusion and
becomes lucid might largely be a matter of chance.
In this context, recall that Voss et al. (2014) found that tACS over prefrontal areas led not
just to lucidity, as defined by knowing that one is dreaming, but also to dissociation.
Participants reported seeing themselves from above, having the feeling of being in a
computer game, being watched, or even being asked to describe their sensory
experiences in dreams. As the participants in this study were not experienced lucid
dreamers, this finding makes sense: It is almost as if electrical stimulation pushed them
in the direction of lucidity by activating the kinds of metacognitive processing and
imagery that are typically associated with insight, but without thereby generating the
explicit, conscious thought that this is a dream. In some cases, participants even explicitly
thought that they were awake. The information that one is now dreaming can be reflected
on different levels. It can be reflected on the level of dream content—for instance, in a
dreamlike sense, in the feeling that this is not quite real, or that one has separated from
one’s body—but also on the level of conscious thought, in the realization that one is now
dreaming or, conversely, in the now firmly held belief that one is awake. Only in the case
of correctly and explicitly realizing that this is a dream can the report be scored as
describing a lucid dream; but there is a deep continuity with these other examples
nonetheless.
Finally, just as dreamers can just know they are dreaming because the dream has taken
on a strange, dreamlike quality, lucidity can also be lost because the dream just seems too
realistic to be a dream. In this example, the dreamer’s attempts to ascertain whether she
really is dreaming seem to prompt exactly the types of imagery that finally lead to a loss
of lucidity.
11
Spontaneous Thought, Insight, and Control in Lucid Dreams
Page 32 of 49
PRINTED FROM OXFORD HANDBOOKS ONLINE (www.oxfordhandbooks.com). (c) Oxford University Press, 2015. All Rights
Reserved. Under the terms of the licence agreement, an individual user may print out a PDF of a single chapter of a title in
Oxford Handbooks Online for personal use.
Subscriber: OUP-Reference Gratis Access; date: 14 April 2018
Example 8: “I am on my way to the bathroom, open the door and find myself in the
wrong bathroom. Rather than standing in my own bathroom, I am in the bathroom
in my parents’ house. This is not at all where I wanted to be and it makes me mad.
I walk through the bathroom and keep telling myself, ‘this can’t be true.’
I can’t believe that this is true, so I look for indications that this could be a dream.
I am very excited and a little bit angry because I don’t want to be here. My mirror
image looks normal; in fact everything looks authentic, just like in reality. This
makes me even angrier, because I know that this is a dream—I shouldn’t be here.
My cellphone rings, but I ignore it (who would be calling me now—my brain is
letting it ring, this isn’t real). I say out loud what I am thinking: ‘This is a dream!’ I
open a window because I figure that my brain won’t also create the entire garden
behind the house. But it does: it’s foggy, gray and wet—just as it should be. I
notice an ugly ceramic frog and a race car in the garden—but immediately concoct
an explanation (my brother has a new car, my father doesn’t know the first thing
about garden decoration). I accept what is happening and give up on trying to
unmask what I am seeing as a dream. Continue to dream
normally. . . .” (unpublished dream report from a student group headed by Ursula
Voss)
Both the onset and the termination of lucidity can be the outcome of spontaneous
metacognitive processing.
Conclusions and Future Challenges
Throughout this chapter, we have argued that lucid dreams involve an intricate interplay
between spontaneous, largely imagistic cognitive processing and metacognitive
insight, deliberate control, and dissociative phenomena. The next step is to place the
investigation of dreaming in general and lucid dreaming in particular in the context of
research on mind-wandering and spontaneous waking thought. In this concluding section,
we suggest what we take to be some of the most exciting research questions for
investigating spontaneous cognitive processing across the sleep-wake cycle.
A first and basic aim is to gather mentation reports across the sleep-wake cycle, ideally
under the same conditions. As timed awakenings, followed by immediate reporting, are
the gold standard for gathering dream reports, a similar method of immediate
retrospection seems well suited to gathering reports of spontaneous waking activity as
well (Windt, 2013, 2015). Existing studies (Stickgold, Malia, Fosse, & Hobson, 2001;
Siclari, LaRocque, Postle, & Tononi, 2013) comparing reports from active and quiet
wakefulness to those from different sleep stages suggest that participants give the
longest reports following REM sleep awakenings, followed by active wakefulness, quiet
wakefulness, NREM sleep, and sleep onset. This somewhat intriguingly suggests that
(p. 404)
Spontaneous Thought, Insight, and Control in Lucid Dreams
Page 33 of 49
PRINTED FROM OXFORD HANDBOOKS ONLINE (www.oxfordhandbooks.com). (c) Oxford University Press, 2015. All Rights
Reserved. Under the terms of the licence agreement, an individual user may print out a PDF of a single chapter of a title in
Oxford Handbooks Online for personal use.
Subscriber: OUP-Reference Gratis Access; date: 14 April 2018
dreams are more easily reported than, for instance, daydreams. Future studies should
aim to carefully compare dream and mind-wandering reports in terms of length, content,
imagery, and emotions. Such studies would, we expect, substantively enrich our
understanding of subtle fluctuations in experience, meta-awareness, control, and thought
contents across the sleep-wake cycle.
A set of more specific questions follows from our sharpened reading, proposed in the first
section of this chapter, of what it means to say that dreams are spontaneous cognitive
processes. There, we introduced the distinction between thinking in dreams (or conscious
thoughts occurring within an ongoing dream) and dreaming as a spontaneous cognitive
process. The motivation for distinguishing these two readings was primarily
phenomenological: Dreaming as such does not feel like thinking; subjectively, dreaming
involves the experience of moving through a dream world and interacting with other
persons and objects in it. Dreams are more vivid and immersive, in this respect, than
even vivid daydreams, which are still experienced as one’s own thought processes. Given
this distinction, one can then investigate the relationship between spontaneous thoughts
experienced within a dream and the lower-level, imagistic, and largely automatic
cognitive processes that underlie the experience of dreaming.
A next step would be to investigate how lucid insight into the fact that one is now
dreaming affects the occurrence and character of conscious thought within dreams.
Based on the occurrence of lucidity lapses, we suggest that even in lucid dreams, thought
is only weakly differentiated from the lower-level processes underlying the production of
dream imagery. But a similar question can now be asked for waking mind-wandering
episodes as well. What exactly is the relationship between imagistic daydreams and
accompanying consciously experienced thoughts (i.e., thoughts occurring within or about
a daydream)? And how does the presence and absence of insight into the fact that one is
now dreaming or that one is now daydreaming, respectively, alter this relationship?
We also proposed that the timing and duration, but also the formal features of dreaming
(i.e., the modality-specific types of imagery experienced in a dream) do not count as
spontaneous cognitive processes in an interesting sense. Spontaneous cognitive
processes are idiosyncratic and hard to predict; they are also amenable, at least in
principle, to deliberate control. By contrast, the timing and duration of dreams, as well as
its formal features, are highly predictable, generic, and governed by internal circadian
rhythms. What is presently unclear is whether the same is true for dream lucidity. Lucid
dreams cannot be prolonged at will, but they can, to an extent, be initiated voluntarily via
autosuggestion. Quite frequently, however, lucidity occurs spontaneously, as a
developmental glitch, a side effect of brain maturation in adolescence. It is also likely
influenced, at least in part, by subcortical processes. This is further supported by the
observation that in many dreams, the realization that this is just a dream is the result of
just knowing; it is a spontaneous insight, rather than the outcome of a conscious
reasoning process, and hence cannot be regarded as an intellectual achievement. Future
Spontaneous Thought, Insight, and Control in Lucid Dreams
Page 34 of 49
PRINTED FROM OXFORD HANDBOOKS ONLINE (www.oxfordhandbooks.com). (c) Oxford University Press, 2015. All Rights
Reserved. Under the terms of the licence agreement, an individual user may print out a PDF of a single chapter of a title in
Oxford Handbooks Online for personal use.
Subscriber: OUP-Reference Gratis Access; date: 14 April 2018
research should aim to determine more precisely the factors that underlie the onset and
maintenance of lucidity.
Again, similar questions can also be applied to the study of spontaneous thought in
wakefulness. A first step would be to investigate the timing and duration of mind-
wandering episodes themselves: Can they be ascribed to a breakdown in attention and
control over one’s conscious thought processes? Or are they governed by a similar
internal rhythm as is the case for non-lucid dreams? If fluctuations in waking conscious
thought were found to be regulated by an internal clock, this would profoundly impact a
host of educational and therapeutic measures. Attempting to deliberately prevent
or reduce the occurrence of mind-wandering might then appear as similarly futile as
attempts to reduce, over long periods of time, the amount and timing of sleep. The
investigation of disturbed sleep and its relation to mind-wandering would also seem to be
central in this context.
But the contrast between lucid and non-lucid dreaming might also elucidate the role of
metacognitive insight and control for spontaneous thought in wakefulness. For example,
what exactly are the cognitive mechanisms underlying insight into the fact that one’s
mind has wandered, and to what extent can this be trained deliberately, as for instance in
mindfulness meditation? There is, of course, a long tradition in Indian philosophy and
contemplative traditions linking mindfulness to lucid insight in dreams (Thompson, 2014).
Recently, it has also been suggested that lucidity is not restricted to dreaming, but that
meditation might also enhance lucid awareness of dreamless sleep (Thompson, 2015a,
2015b; Windt, 2015b; Windt et al., 2016). A next step would be to investigate this
relationship in more detail. How exactly do different styles of meditation enhance the
frequency of lucidity in dreams and in dreamless sleep, but also in waking mind-
wandering? Do experienced lucid dreamers report fewer episodes of waking mind-
wandering, perhaps because they more easily notice when their thoughts are about to
drift away from an ongoing task? Or do they experience more frequent and more vivid
daydreams, but are simultaneously more aware of mind wandering throughout the
episodes? To what extent, in other words, are metacognitive insight and control
compatible with spontaneous thought in wakefulness, much as we have been arguing is
the case for dreaming (see also Fox & Christoff, 2014; for a discussion of intentional
versus unintentional mind-wandering and their relation to mind-wandering with and
without awareness, see Seli et al., 2016a, b)?
Finally, the experimental induction of lucid dreams via tACS raises a number of questions
about the nature of lucidity itself. Is the transition between lucid and non-lucid dreaming
really as sharp as suggested by enthusiastic descriptions in the literature, where lucidity
is often said to involve an all-pervasive change in the clarity of imagery and reasoning? Or
do lucid dreams rather lie on a continuum with non-lucid ones, with pre-lucid dreams,
false awakenings, tacit lucidity, dissociative phenomena, and control occupying
intermediate positions on the spectrum? If lucid insight, as suggested here, often exists
alongside the types of spontaneous cognitive processing, including erratic reasoning, that
(p. 405)
Spontaneous Thought, Insight, and Control in Lucid Dreams
Page 35 of 49
PRINTED FROM OXFORD HANDBOOKS ONLINE (www.oxfordhandbooks.com). (c) Oxford University Press, 2015. All Rights
Reserved. Under the terms of the licence agreement, an individual user may print out a PDF of a single chapter of a title in
Oxford Handbooks Online for personal use.
Subscriber: OUP-Reference Gratis Access; date: 14 April 2018
characterize many non-lucid dreams, this would suggest that the difference between lucid
and non-lucid dreams is gradual rather than absolute.
But we can also ask about the necessary and sufficient conditions for the induction of
dream lucidity at the level of brain activation. We have already pointed out that 40 Hz
activity in prefrontal areas appears to be necessary but not sufficient for dream lucidity.
This is closely linked to the question of whether, as we tentatively proposed in the second
section of this chapter, lucid REM sleep can be identified as a separate substage of REM
sleep. If so, this could lead to a refinement of sleep-stage scoring criteria as well. To
achieve this, the experimental induction of lucidity will have to be optimized in order to
turn lucidity into a predictable and easily replicable phenomenon. Future research should
aim to determine the precise duration and strength of stimulation that is sufficient to
induce lucidity, even in inexperienced participants. A next step would be to investigate
the effect of 40 Hz stimulation outside of REM sleep. Would stimulation not only in
waking participants, but also in NREM sleep increase the probability of insight and
control over ongoing thought content, as well as dissociative phenomena? For instance,
might stimulation lead to perspective changes in ongoing daydreams? Interestingly,
Axelrod, Rees, Lavidor, Bar (2015) have recently reported that the application of
transcranial direct current stimulation (tDCS) to lateral prefrontal areas increases the
number of episodes of mind-wandering. However, as Fox and Christoff (2015) point out,
the actual effect may have been an enhancement of meta-awareness of mind-wandering,
prompting a higher number of reports, instead of an actual increase in the frequency of
mind-wandering episodes. If so, this would again suggest that insight and spontaneous
thought are not just consistent, but perhaps intimately and systematically related.
Clearly, researchers are only beginning to address these questions, and many of the
points we make throughout this chapter are preliminary and speculative. But we hope
that they are nonetheless useful in identifying points of contact between emerging lines
of research that so far remain largely separate: the scientific investigation of dreaming,
including lucid dreaming, and research on mind-wandering and spontaneous thought in
wakefulness. Bringing these lines of research together is, we think, a promising and
exciting project for the future, and we hope to have shown how the analysis of
dream lucidity can contribute to this, both theoretically and experimentally.
References
Aristoteles & Gallop, D. (1996). Aristotle on Sleep and Dreams: A Text and Translation:
Cambridge: Cambridge University Press.
Arnold-Forster, M. L. S.-M. (1921). Studies in dreams. New York: Macmillan.
Aserinsky, E., & Kleitman, N. (1953). Regularly occurring periods of eye motility, and
concomitant phenomena, during sleep. Science, 118(3062), 273–274.
(p. 406)
Spontaneous Thought, Insight, and Control in Lucid Dreams
Page 36 of 49
PRINTED FROM OXFORD HANDBOOKS ONLINE (www.oxfordhandbooks.com). (c) Oxford University Press, 2015. All Rights
Reserved. Under the terms of the licence agreement, an individual user may print out a PDF of a single chapter of a title in
Oxford Handbooks Online for personal use.
Subscriber: OUP-Reference Gratis Access; date: 14 April 2018
Augustine, C. (1991). Confessions. (Henry Chadwick, Trans.). Oxford: Oxford University
Press.
Axelrod, V., Rees, G., Lavidor, M., & Bar, M. (2015). Increasing propensity to mind-wander
with transcranial direct current stimulation. Proceedings of the National Academy of
Sciences, 112(11), 3314–3319.
Baddeley, A. (1992). Working memory. Science, 255(5044), 556–559.
Bargh, J. A., Gollwitzer, P. M., Lee-Chai, A., Barndollar, K., & Trötschel, R. (2001). The
automated will: Nonconscious activation and pursuit of behavioral goals. Journal of
Personality and Social Psychology, 81(6), 1014.
Blagrove, M., Blakemore, S.-J., & Thayer, B. R. (2006). The ability to self-tickle following
rapid eye movement sleep dreaming. Consciousness and Cognition, 15(2), 285–294.
Blakemore, S.-J., Wolpert, D., & Frith, C. (2000). Why can’t you tickle yourself?
Neuroreport, 11(11), R11–R16.
Blanke, O., Landis, T., Spinelli, L., & Seeck, M. (2004). Out‐of‐body experience and
autoscopy of neurological origin. Brain, 127(2), 243–258.
Blanke, O., & Mohr, C. (2005). Out-of-body experience, heautoscopy, and autoscopic
hallucination of neurological origin: Implications for neurocognitive mechanisms of
corporeal awareness and self-consciousness. Brain Research Reviews, 50(1), 184–199.
Brooks, J. E., & Vogelsong, J. (2000). The conscious exploration of dreaming: Discovering
how we create and control our dreams. New York: 1st Books Library.
Brugger, P., Regard, M., & Landis, T. (1997). Illusory reduplication of one's own body:
phenomenology and classification of autoscopic phenomena. Cognitive Neuropsychiatry,
2(1), 19–38.
Carruthers, P. (2015). The centered mind, New York: Oxford University Press.
Carciofo, R., Du, F., Song, N., & Zhang, K. (2014). Mind wandering, sleep quality, affect
and chronotype: an exploratory study. PloS one, 9(3), e91285.
Christoff, K., Gordon, A., Smith, R., Vartanian, O., & Mandel, D. (2011). The role of
spontaneous thought in human cognition. Neuroscience of Decision Making, 1, 259–284.
Christoff, K., Irving, Z. C., Fox, K. C., Spreng, R. N., & Andrews-Hanna, J. R. (2016). Mind-
wandering as spontaneous thought: a dynamic framework. Nature Reviews Neuroscience,
17(11), 718–731.
Czisch, M. (2014). The boundaries of consciousness: Lucid dreaming. Journal of Sleep
Research, 23, 63.
Spontaneous Thought, Insight, and Control in Lucid Dreams
Page 37 of 49
PRINTED FROM OXFORD HANDBOOKS ONLINE (www.oxfordhandbooks.com). (c) Oxford University Press, 2015. All Rights
Reserved. Under the terms of the licence agreement, an individual user may print out a PDF of a single chapter of a title in
Oxford Handbooks Online for personal use.
Subscriber: OUP-Reference Gratis Access; date: 14 April 2018
Dement, W., & Kleitman, N. (1957). Cyclic variations in EEG during sleep and their
relation to eye movements, body motility, and dreaming. Electroencephalography and
clinical neurophysiology, 9(4), 673–690.
Dennett, D. C. (1976). Are dreams experiences? The Philosophical Review, 85(2), 151–
171.
Descartes, R., & Cottingham, J. (2013). René Descartes: Meditations on first philosophy:
With selections from the objections and replies. Cambridge: Cambridge University Press.
Diekelmann, S., & Born, J. (2010). The memory function of sleep. Nature Reviews
Neuroscience, 11(2), 114.
Dodet, P., Chavez, M., Leu-Semenescu, S., Golmard, J.-L., & Arnulf, I. (2014). Lucid
dreaming in narcolepsy. Sleep, 38(3), 487–497.
Dokic, J. (2012). Seeds of self-knowledge: Noetic feelings and metacognition. Foundations
of Metacognition, 1, 302–321.
Domhoff, G. William. (2011). The neural substrate for dreaming: Is it a subsystem of the
default network? Consciousness and Cognition, 20(4), 1163–1174. doi: 10.1016/j.concog.
2011.03.001
Domhoff, G. W. (2013). Finding meaning in dreams: A quantitative approach. New York:
Springer Science & Business Media.
Dorsch, F. (2015). Focused daydreaming and mind-wandering. Review of Philosophy and
Psychology, 6(4), 1–23.
Dresler, M., Eibl, L., Fischer, C. F., Wehrle, R., Spoormaker, V. I., Steiger, A., . . .
Pawlowski, M. (2013). Volitional components of consciousness vary across wakefulness,
dreaming and lucid dreaming. Frontiers in Psychology, 4, 987.
Dresler, M., Wehrle, R., Spoormaker, V. I., Koch, S. P., Holsboer, F., Steiger, A., . . . Czisch,
M. (2012). Neural correlates of dream lucidity obtained from contrasting lucid versus
non-lucid REM sleep: A combined EEG/fMRI case study. Sleep, 35(7), 1017.
Erlacher, D., Schädlich, M., Stumbrys, T., & Schredl, M. (2013). Time for actions in lucid
dreams: Effects of task modality, length, and complexity. Frontiers in Psychology, 4, 1013.
Espie, C. A., Broomfield, N. M., MacMahon, K. M., Macphee, L. M., & Taylor, L. M. (2006).
The attention–intention–effort pathway in the development of psychophysiologic
insomnia: A theoretical review. Sleep Medicine Reviews, 10(4), 215–245.
Filevich, E., Dresler, M., Brick, T. R., & Kühn, S. (2015). Metacognitive mechanisms
underlying lucid dreaming. The Journal of Neuroscience, 35(3), 1082–1088.
Spontaneous Thought, Insight, and Control in Lucid Dreams
Page 38 of 49
PRINTED FROM OXFORD HANDBOOKS ONLINE (www.oxfordhandbooks.com). (c) Oxford University Press, 2015. All Rights
Reserved. Under the terms of the licence agreement, an individual user may print out a PDF of a single chapter of a title in
Oxford Handbooks Online for personal use.
Subscriber: OUP-Reference Gratis Access; date: 14 April 2018
Fosse, R., Stickgold, R., & Hobson, J. A. (2001). Brain-mind states: Reciprocal
variation in thoughts and hallucinations. Psychological Science, 12(1), 30–36.
Fosse, R., Stickgold, R., & Hobson, J. A. (2004). Thinking and hallucinating: Reciprocal
changes in sleep. Psychophysiology, 41(2), 298–305.
Fox, K. C., & Christoff, K. (2014). Metacognitive facilitation of spontaneous thought
processes: When metacognition helps the wandering mind find its way. In S. M. Fleming
& C. D. Frith (Eds.), The cognitive neuroscience of metacognition (pp. 293–319). Berlin:
Springer.
Fox, K. C. R., Nijeboer, S., Solomonova, E., Domhoff, G. W., & Christoff, K. (2013).
Dreaming as mind wandering: Evidence from functional neuroimaging and first-person
content reports. Frontiers in Human Neuroscience, 7, 412. doi: 10.3389/fnhum.
2013.00412
Franklin, M. S., Mrazek, M. D., Anderson, C. L., Smallwood, J., Kingstone, A., & Schooler,
J. W. (2013). The silver lining of a mind in the clouds: Interesting musings are associated
with positive mood while mind-wandering. Frontiers in psychology, 4, 583.
Gackenbach, J. (1988). The psychological content of lucid versus nonlucid dreams. In J.
Gackenbach & S. LaBerge (Eds.), Conscious mind, sleeping brain (pp. 181–220). Boston:
Springer.
Goleman, D., & Davidson, R. (1979). Consciousness: Brain, States of awareness and
mysticism. New York: Harpcr & Row.
Green, C. E. (1968). Lucid dreams (Vol. 1). Oxford: Institute of Psychophysical Research.
Green, C. E., & McCreery, C. (1994). Lucid dreaming: The paradox of consciousness
during sleep. New York: Psychology Press.
Hanna, R., & Thompson, E. (2003). Neurophenomenology and the spontaneity of
consciousness. Canadian Journal of Philosophy, 33(Suppl 1), 133–162.
Hartmann, E. (1975). Dreams and other hallucinations: An approach to the underlying
mechanism. In R. K. Siegel & L. J. West (Eds.), Hallucinations: Behavior, experience and
theory (pp. 71–79). New York: John Wiley & Sons.
Hearne, K. M. (1978). Lucid dreams: An elecro-physiological and psychological study.
Liverpool: Liverpool University.
Hobson, A., & Voss, U. (2011). A mind to go out of: Reflections on primary and secondary
consciousness. Consciousness and Cognition, 20(4), 993–997.
Hobson, J., & Voss, U. (2010). Lucid dreaming and the bimodality of consciousness. In E.
Perry, D. Collerton, & F. LeBeau (Eds.), New horizons in the neuroscience of
consciousness (Vol. 79, pp. 155–165).
(p. 408)
Spontaneous Thought, Insight, and Control in Lucid Dreams
Page 39 of 49
PRINTED FROM OXFORD HANDBOOKS ONLINE (www.oxfordhandbooks.com). (c) Oxford University Press, 2015. All Rights
Reserved. Under the terms of the licence agreement, an individual user may print out a PDF of a single chapter of a title in
Oxford Handbooks Online for personal use.
Subscriber: OUP-Reference Gratis Access; date: 14 April 2018
Hobson, J. A. (1988). The dreaming brain. New York: Basic Books.
Hobson, J. A. (1999). Dreaming as delirium: How the brain goes out of its mind.
Cambridge, MA: MIT Press.
Hobson, J. A., Pace-Schott, E. F., & Stickgold, R. (2000). Dreaming and the brain: Toward
a cognitive neuroscience of conscious states. Behavioral and Brain Sciences, 23(06), 793–
842.
Ichikawa, J. (2009). Dreaming and imagination. Mind & Language, 24(1), 103–121.
Irving, Z. C. (2016). Mind-wandering is unguided attention: Accounting for the
“purposeful” wanderer. Philosophical Studies, 173, 547–571.
Kahan, T. L. (2001). Consciousness in dreaming: A metacognitive approach. In K. Bulkeley
(Ed.), Dreams (pp. 333–360). New York: Palgrave Macmillan.
Kahn, D., & Hobson, J. A. (2005). State-dependent thinking: A comparison of waking and
dreaming thought. Consciousness and Cognition, 14(3), 429–438.
Kaliuzhna, M., Vibert, D., Grivaz, P., & Blanke, O. (2015). Out-of-body experiences and
other complex dissociation experiences in a patient with unilateral peripheral vestibular
damage and deficient multisensory integration. Multisensory Research, 28(5–6), 613–635.
Kam, J. W., & Handy, T. C. (2013). The neurocognitive consequences of the wandering
mind: A mechanistic account of sensory-motor decoupling. Frontiers in Psychology, 4,
725.
Killingsworth, M. A., & Gilbert, D. T. (2010). A wandering mind is an unhappy mind.
Science, 330(6006), 932. doi: 10.1126/science.1192439
Kramer, M. (2013). The dream experience: A systematic exploration. New York:
Routledge.
LaBerge, S. (1985). Lucid dreaming: The power of being awake and aware in your
dreams. Los Angeles: Jeremy P. Tarcher.
LaBerge, S., & DeGracia, D. J. (2000). Varieties of lucid dreaming experience. In R. G.
Kunzendorf & B. Wallace (Eds.), Individual differences in conscious experience (pp. 269–
307). Amsterdam: John Benjamins.
LaBerge, S., Phillips, L., & Levitan, L. (1994). An hour of wakefulness before morning
naps makes lucidity more likely. NightLight: Lucidity Institute Newsletter, 6(3), 1–4.
LaBerge, S. (1990). Lucid dreaming: Psychophysiological studies of consciousness during
REM sleep. In R. R. Bootzin, J. F. Kihlstrom & D. L. Schacter (Eds.), Sleep and Cognition
(pp. 109–126). Washington D.C.: Amercan Psychological Associatioan.
Spontaneous Thought, Insight, and Control in Lucid Dreams
Page 40 of 49
PRINTED FROM OXFORD HANDBOOKS ONLINE (www.oxfordhandbooks.com). (c) Oxford University Press, 2015. All Rights
Reserved. Under the terms of the licence agreement, an individual user may print out a PDF of a single chapter of a title in
Oxford Handbooks Online for personal use.
Subscriber: OUP-Reference Gratis Access; date: 14 April 2018
Leibniz, G. W. (1956). Philosophical papers and letters: A selection (L. E. Loemker,
Trans.). Chicago: University of Chicago Press.
Levitan, L. (1994). A fool’s guide to lucid dreaming. Nightlight, 6(2), 1–5.
Malcolm, N. (1962). Dreaming, 2nd. ed. London: Routledge and Kegan Paul.
Maury, A. (1861). Le sommeil et les rêves. Paris: Didier.
McGinn, C., & McGinn, C. (2009). Mindsight: Image, dream, meaning. Cambridge, MA:
Harvard University Press.
McMillan, R. L., Kaufman, S. B., & Singer, J. L. (2013). Ode to positive constructive
daydreaming. Frontiers in Psychology, 4, 626. doi: 10.3389/fpsyg.2013.00626
McNamara, P., McLaren, D., Smith, D., Brown, A., & Stickgold, R. (2005). A “Jekyll and
Hyde” within aggressive versus friendly interactions in REM and non-REM dreams.
Psychological Science, 16(2), 130–136.
Metzinger, T. (2004). Being no one: The self-model theory of subjectivity. Cambridge, MA:
MIT Press.
Metzinger, T. (2013). The myth of cognitive agency: Subpersonal thinking as a cyclically
recurring loss of mental autonomy. Frontiers in Psychology, 4, 931. doi: 10.3389/fpsyg.
2013.00931
Metzinger, T. (2015). M-Autonomy. Journal of Consciousness Studies, 22(11–12), 270–302.
Metzinger, T., & Windt, J. (2014). Die phänomenale Signatur des Wissens: Experimentelle
Philosophie des Geistes mit oder ohne Intuitionen. In T. Grundmann, J. Horvath & J.
Kipper (Eds.) Die Experimentelle Philosophie in der Diskussion (pp. 279–321). Berlin:
Suhrkamp.
Metzinger, T., & Windt, J. M. (2015). What does it mean to have an open mind? In T.
Metzinger & J. M. Windt (Eds.), Open MIND, 0(GI). Frankfurt am Main: MIND Group.
Naro, A., Bramanti, P., Leo, A., Russo, M., & Calabro, R. S. (2016). Transcranial
alternating current stimulation in patients with chronic disorder of consciousness: A
possible way to cut the diagnostic Gordian knot? Brain Topography, 29(4), 623–644. doi:
10.1007/s10548-016-0489-z
Nielsen, T. (2014). What is the current status of your “covert REM Process” theory,
especially in the light of the new protoconsciousness hypothesis? In N. Tranquillo (Ed.),
Dream consciousness (pp. 175–180). Vienna: Springer.
Nielsen, T. A. (1993). Changes in the kinesthetic content of dreams following
somatosensory stimulation of leg muscles during REM sleep. Dreaming, 3(2), 99.
(p. 409)
Spontaneous Thought, Insight, and Control in Lucid Dreams
Page 41 of 49
PRINTED FROM OXFORD HANDBOOKS ONLINE (www.oxfordhandbooks.com). (c) Oxford University Press, 2015. All Rights
Reserved. Under the terms of the licence agreement, an individual user may print out a PDF of a single chapter of a title in
Oxford Handbooks Online for personal use.
Subscriber: OUP-Reference Gratis Access; date: 14 April 2018
Nielsen, T. A. (2000). A review of mentation in REM and NREM sleep: “Covert” REM
sleep as a possible reconciliation of two opposing models. Behavioral and Brain Sciences,
23(06), 851–866.
Nielsen, T. (2017). Microdream neurophenomenology. Neuroscience of Consciousness,
3(1), 1–17.
Noreika, V., Windt, J. M., Lenggenhager, B., & Karim, A. A. (2010). New perspectives for
the study of lucid dreaming: From brain stimulation to philosophical theories of self-
consciousness. International Journal of Dream Research, 3(1), 36–45.
Pace-Schott, E. F. (2013). Dreaming as a story-telling instinct. Frontiers in Psychology, 4,
159.
Pearson, D. G., & Hollings, J. (2013). Einstein’s jacket: Evidence for long-term perceptual
specificity in mental imagery. Consciousness and Cognition, 22(1), 148–154. doi: http://
dx.doi.org/10.1016/j.concog.2012.11.004
Rahimi, S., Naghibi, S. M., Mokhber, N., Schredl, M., Assadpour, H., Farkhani, A. R., . . .
Naghibi, S. S. (2015). Sophisticated evaluation of possible effect of distinct auditory
stimulation during REM sleep on dream content. International Journal of Dream
Research, 8(2), 146–151.
Revonsuo, A. (2006). Inner presence: Consciousness as a biological phenomenon.
Cambridge, MA: MIT Press.
Revonsuo, A., Tuominen, J., & Valli, K. (2015a). The avatars in the machine: Dreaming as
a simulation of social reality. In T. Metzinger & J. Windt (Eds.), Open MIND, 32(T).
Frankfurt am Main: MIND Group.
Revonsuo, A., Tuominen, J., & Valli, K. (2015b). The simulation theories of dreaming: How
to make theoretical progress in dream science. In T. Metzinger & J. Windt (Eds.), Open
MIND, 32(R). Frankfurt am Main: MIND Group.
Rosen, M. G. (2015). I’m thinking your thoughts while I sleep: Sense of agency and
ownership over dream thought. Psychology of Consciousness: Theory, Research, and
Practice, 2(3), 326.
Ruby, F. J. M., Smallwood, J., Engen, H., & Singer, T. (2013). How self-generated thought
shapes mood: The relation between and mood depends on the socio-temporal content of
thoughts. PLoS One, 8(10), e77554. doi: 10.1371/journal.pone.0077554
Sagnier, S., Coulon, P., Chaufton, C., Poli, M., Debruxelles, S., Renou, P., . . . Sibon, I.
(2015). Lucid dreams, an atypical sleep disturbance in anterior and mediodorsal thalamic
strokes. Revue Neurologique, 171(11), 768–772.
Spontaneous Thought, Insight, and Control in Lucid Dreams
Page 42 of 49
PRINTED FROM OXFORD HANDBOOKS ONLINE (www.oxfordhandbooks.com). (c) Oxford University Press, 2015. All Rights
Reserved. Under the terms of the licence agreement, an individual user may print out a PDF of a single chapter of a title in
Oxford Handbooks Online for personal use.
Subscriber: OUP-Reference Gratis Access; date: 14 April 2018
Saint-Denys, H. d. (1982). Dreams and the means of directing them. London: Duckworth.
Edited by M. Schatzman & translated by N. Fry from the French, Les rives et les moyens
de les diriger (1867). Paris: Amyat.
Sanchez-Vives, M. V., & Slater, M. (2005). From presence to consciousness through
virtual reality. Nature Reviews Neuroscience, 6(4), 332–339.
Schatzman, M., Worsley, A., & Fenwick, P. (1988). Correspondence during lucid dreams
between dreamed and actual events. In J. Gackenbach & S. LaBerge (Eds.), Conscious
Mind, Sleeping Brain (pp. 155–179). Boston: Springer.
Schmidt, R. E., & Gendolla, G. H. (2008). Dreaming of white bears: The return of the
suppressed at sleep onset. Consciousness and Cognition, 17(3), 714–724.
Schmidt, R. E., Renaud, O., & Van Der Linden, M. (2011). Nocturnal regrets and insomnia
in elderly people. The International Journal of Aging and Human Development, 73(4),
371–393.
Schmidt, R. E., & Van der Linden, M. (2009). The aftermath of rash action: Sleep-
interfering counterfactual thoughts and emotions. Emotion, 9(4), 549.
Schmidt, R. E., & Van der Linden, M. (2013). Feeling too regretful to fall asleep:
Experimental activation of regret delays sleep onset. Cognitive Therapy and Research,
37(4), 872–880.
Schmidt, S. C., Stumbrys, T., & Erlacher, D. (2014). Dream characters and the dream ego:
An exploratory online study in lucid dreams. Dreaming, 24(2), 138.
Schooler, J. W., Smallwood, J., Christoff, K., Handy, T. C., Reichle, E. D., & Sayette, M. A.
(2011). Meta-awareness, perceptual decoupling and the wandering mind. Trends in
Cognitive Sciences, 15(7), 319–326. doi: 10.1016/j.tics.2011.05.006
Schredl, M., Atanasova, D., Hörmann, K., Maurer, J. T., Hummel, T., & Stuck, B. A. (2009).
Information processing during sleep: The effect of olfactory stimuli on dream content and
dream emotions. Journal of Sleep Research, 18(3), 285–290.
Schredl, M., Henley-Einion, J., & Blagrove, M. (2012). Lucid dreaming in children: The UK
library study. International Journal of Dream Research, 5(1), 94–98.
Schwitzgebel, E. (2011). Perplexities of consciousness. Cambridge, MA: MIT Press.
Scott, J. G., & Schoenberg, M. R. (2011). Frontal lobe/executive functioning. In The little
black book of neuropsychology (pp. 219–248). Springer US.
Seli, P., Risko, E. F., & Smilek, D. (2016a). On the necessity of distinguishing between
unintentional and intentional mind wandering. Psychological Science, 27(5), 685–691.
Spontaneous Thought, Insight, and Control in Lucid Dreams
Page 43 of 49
PRINTED FROM OXFORD HANDBOOKS ONLINE (www.oxfordhandbooks.com). (c) Oxford University Press, 2015. All Rights
Reserved. Under the terms of the licence agreement, an individual user may print out a PDF of a single chapter of a title in
Oxford Handbooks Online for personal use.
Subscriber: OUP-Reference Gratis Access; date: 14 April 2018
Seli, P., Risko, E. F., Smilek, D., & Schacter, D. L. (2016b). Mind-wandering with and
without intention. Trends Cogn Sci, 20(8), 605–617.
Siclari, F., LaRocque, J. J., Postle, B. R., & Tononi, G. (2013). Assessing sleep
consciousness within subjects using a serial awakening paradigm. Frontiers in
Psychology, 4, 542.
Silber, M. H., Ancoli-Israel, S., Bonnet, M. H., Chokroverty, S., Grigg-Damberger, M. M.,
Hirshkowitz, M., Kapen, S., Keenan, S., Kryger, M., Penzel, T.Pressman, M., Iber, C.
(2007). The visual scoring of sleep in adults. J Clin Sleep Med, 3(2), 121–131.
Slater, M. (2009). Place illusion and plausibility can lead to realistic behaviour in
immersive virtual environments. Philosophical Transactions of the Royal Society B:
Biological Sciences, 364(1535), 3549–3557.
Smallwood, J., & Andrews-Hanna, J. (2013). Not all minds that wander are lost: The
importance of a balanced perspective on the mind-wandering state. Frontiers in
Psychology, 4, 441. doi: 10.3389/fpsyg.2013.00441
Smallwood, J., & Schooler, J. W. (2015). The science of mind wandering: Empirically
navigating the stream of consciousness. Annual Review of Psychology, 66, 487–518. doi:
10.1146/annurev-psych-010814-015331
Stenstrom, P., Fox, K., Solomonova, E., & Nielsen, T. (2012). Mentation during
sleep onset theta bursts in a trained participant: A role for NREM stage 1 sleep in
memory processing? International Journal of Dream Research, 5(1), 37–46.
Stickgold, R. (2005). Sleep-dependent memory consolidation. Nature, 437(7063), 1272–
1278.
Stickgold, R., Malia, A., Fosse, R., & Hobson, J. A. (2001). Brain–mind states: I.
Longitudinal field study of sleep/wake factors influencing mentation report length. Sleep,
24(2), 171–179.
Stumbrys, T., Erlacher, D., Johnson, M., & Schredl, M. (2014). The phenomenology of
lucid dreaming: An online survey. The American Journal of Psychology, 127(2), 191–204.
Stumbrys, T., Erlacher, D., Schädlich, M., & Schredl, M. (2012). Induction of lucid
dreams: A systematic review of evidence. Consciousness and Cognition, 21(3), 1456–
1475.
Stumbrys, T., Erlacher, D., & Schmidt, S. (2011). Lucid dream mathematics: An
explorative online study of arithmetic abilities of dream characters. International Journal
of Dream Research, 4(1), 35–40.
Stuss, D. T. (2011). Functions of the frontal lobes: relation to executive functions. Journal
of the international neuropsychological Society, 17(5), 759–765.
(p. 410)
Spontaneous Thought, Insight, and Control in Lucid Dreams
Page 44 of 49
PRINTED FROM OXFORD HANDBOOKS ONLINE (www.oxfordhandbooks.com). (c) Oxford University Press, 2015. All Rights
Reserved. Under the terms of the licence agreement, an individual user may print out a PDF of a single chapter of a title in
Oxford Handbooks Online for personal use.
Subscriber: OUP-Reference Gratis Access; date: 14 April 2018
Tart, C. T. (1988). From spontaneous event to lucidity. In J. Gackenbach & S. LaBerge
(Eds.), Conscious mind, sleeping brain (pp. 67–103). Boston: Springer.
Tholey, P., & Utecht, K. (1987). Schöpferisch träumen. Der Klartraum als Lebenshilfe.
Niedernhausen: Falken-Verlag.
Thompson, E. (2014). Waking, dreaming, being: Self and consciousness in neuroscience,
meditation, and philosophy. New York: Columbia University Press.
Thompson, E. (2015a). Dreamless sleep, the embodied mind, and consciousness. In T.
Metzinger & J. Windt (Eds.), Open MIND, 37(T). Frankfurt am Main: MIND Group.
Thompson, E. (2015b). Steps toward a neurophenomenology of conscious sleep. Open
MIND, 37(R). Frankfurt am Main: MIND Group.
van Eeden, F. (1913). A study of dreams. Paper presented at the Proceedings of the
Society for Psychical Research.
van Rijn, E., Eichenlaub, J.-B., Lewis, P., Walker, M., Gaskell, M., Malinowski, J., &
Blagrove, M. (2015). The dream-lag effect: Selective processing of personally significant
events during rapid eye movement sleep, but not during slow wave sleep. Neurobiology of
Learning and Memory, 122, 98–109.
Voss, U., Frenzel, C., Koppehele-Gossel, J., & Hobson, A. (2012). Lucid dreaming: An age‐
dependent brain dissociation. Journal of Sleep Research, 21(6), 634–642.
Voss, U., & Hobson, A. (2015). What is the state-of-the-art on lucid dreaming? In T.
Metzinger & J. Windt (Eds.), Open MIND, 38(T). Frankfurt am Main: MIND Group.
Voss, U., Holzmann, R., Hobson, A., Paulus, W., Koppehele-Gossel, J., Klimke, A., &
Nitsche, M. A. (2014). Induction of self awareness in dreams through frontal low current
stimulation of gamma activity. Nature Neuroscience, 17(6), 810–812.
Voss, U., Holzmann, R., Tuin, I., & Hobson, J. A. (2009). Lucid dreaming: A state of
consciousness with features of both waking and non-lucid dreaming. Sleep, 32(9), 1191.
Voss, U., Schermelleh-Engel, K., Windt, J., Frenzel, C., & Hobson, A. (2013). Measuring
consciousness in dreams: The lucidity and consciousness in dreams scale. Consciousness
and Cognition, 22(1), 8–21.
Voss, U., Tuin, I., Schermelleh-Engel, K., & Hobson, A. (2011). Waking and dreaming:
Related but structurally independent. Dream reports of congenitally paraplegic and deaf-
mute persons. Consciousness and Cognition, 20(3), 673–687.
Voss, U., & Voss, G. (2014). A neurobiological model of lucid dreaming. In R. Hurd & K.
Bulkeley (Eds.), Lucid dreaming: New perspectives on consciousness in sleep (pp. 23–36).
Santa Barbara, CA, Praeger.
Spontaneous Thought, Insight, and Control in Lucid Dreams
Page 45 of 49
PRINTED FROM OXFORD HANDBOOKS ONLINE (www.oxfordhandbooks.com). (c) Oxford University Press, 2015. All Rights
Reserved. Under the terms of the licence agreement, an individual user may print out a PDF of a single chapter of a title in
Oxford Handbooks Online for personal use.
Subscriber: OUP-Reference Gratis Access; date: 14 April 2018
Wegner, D. M., Schneider, D. J., Carter, S. R., & White, T. L. (1987). Paradoxical effects of
thought suppression. Journal of Personality and Social Psychology, 53(1), 5.
Wegner, D. M., Wenzlaff, R. M., & Kozak, M. (2004). Dream rebound: The return of
suppressed thoughts in dreams. Psychological Science, 15(4), 232–236.
Wegner, D. M., & Zanakos, S. (1994). Chronic thought suppression. Journal of Personality,
62(4), 615–640.
Windt, J. M. (2013). Reporting dream experience: Why (not) to be skeptical about dream
reports. Frontiers in Human Neuroscience, 7, 708.
Windt, J. M. (2015a). Dreaming: A conceptual framework for philosophy of mind and
empirical research. Cambridge, MA: MIT Press.
Windt, J. M. (2015b). Just in time: Dreamless sleep experience as pure subjective
temporality. In T. Metzinger & J. Windt (Eds.), Open MIND, 37(C). Frankfurt am Main:
MIND Group.
Windt, J. M. (2017). Predictive brains, dreaming selves, sleeping bodies: How the analysis
of dream movement can inform a theory of self- and world-simulation in dreams.
Synthese. doi:10.1007/s11229-017-1525-6
Windt, J. M., Harkness, D. L., & Lenggenhager, B. (2014). Tickle me, I think I might be
dreaming! Sensory attenuation, self-other distinction, and predictive processing in lucid
dreams. Frontiers in Human Neuroscience, 8, 717.
Windt, J. M., & Metzinger, T. (2007). The philosophy of dreaming and self-consciousness:
What happens to the experiential subject during the dream state? In D. Barett & P.
McNamara (Eds.), The New Science of Dreaming. Vol. 3: Cultural and Theoretical
Perspectives (pp. 193–248). Westport; London: Praeger Perspectives.
Windt, J. M., & Noreika, V. (2011). How to integrate dreaming into a general theory of
consciousness: A critical review of existing positions and suggestions for future research.
Consciousness and Cognition, 20(4), 1091–1107.
Windt, J. M., Nielsen, T., & Thompson, E. (2016). Does consciousness disappear in
dreamless sleep? Trends in Cognitive Sciences, 20(12), 871–882.
Wolfson, A. R., & Carskadon, M. A. (2003). Understanding adolescent’s sleep patterns
and school performance: A critical appraisal. Sleep Medicine Reviews, 7(6), 491–506.
Worsley, A. (1988). Personal experiences in lucid dreaming. In J. Gackenbach & S.
LaBerge (Eds.), Conscious mind, sleeping brain (pp. 321–341). Boston: Springer.
Notes:
Spontaneous Thought, Insight, and Control in Lucid Dreams
Page 46 of 49
PRINTED FROM OXFORD HANDBOOKS ONLINE (www.oxfordhandbooks.com). (c) Oxford University Press, 2015. All Rights
Reserved. Under the terms of the licence agreement, an individual user may print out a PDF of a single chapter of a title in
Oxford Handbooks Online for personal use.
Subscriber: OUP-Reference Gratis Access; date: 14 April 2018
(1.) Note that on a purely semantic level, task- and stimulus-independence do not appear
to be necessary for spontaneous thought. One might well have spontaneous thoughts
about a task to which all of one’s attentional resources are currently directed and in
which one is fully absorbed; and these thoughts might well be triggered by environmental
stimuli. In our definition, these cases still count as spontaneous to the extent that they
are only weakly constrained, rather than directly determined, by the tasks and/or external
stimuli they are arising in response to. This is a subtle difference, but it opens the door to
saying that spontaneous thoughts can be task-relevant, for instance by being guided by
unconscious goal representations. Empirical evidence suggests that goals can indeed be
activated and pursued automatically; explicit awareness of one’s intentions is apparently
not necessary for the guidance of goal-directed behavior (Bargh et al. 2001). We return to
this point later, in section 3. For now, we merely want to emphasize that there is no
conceptual contradiction involved in saying that spontaneous thought can be goal-
directed and can contribute to the solution of ongoing tasks.
(2.) Simulation views also give a clear sense to types of experience occurring in sleep that
do not count as dreamful because they are not immersive and lack the experience of a
self in a world (Windt et al., 2016). Asking how these types of dreamless sleep experience
relate to spontaneous thought in wakefulness is an important question for future
research.
(3.) A related question, which is mostly confined to the philosophical literature and tends
to run parallel to the discussion of dreaming in the context of psychological and
neuroscientific theories of mind-wandering and spontaneous thought, is whether
dreaming involves the same kind of mental state as perceiving and hallucinating or
whether dreams are imaginative experiences. The imagination view of dreaming is
sometimes tied to the phenomenological claim that dreaming actually feels like
daydreaming and imagining (McGinn 2009; Ichikawa 2009); the experience of presence in
a dream is, in this view, similar to being deeply absorbed in a novel or movie. This view
has interesting consequences for thinking about the relationship between dreaming,
imagination, and control. While spontaneous thought and mind-wandering are typically
described as involving a loss of control, imagination, at least in the philosophical
literature, is often held to be active and controllable and is contrasted with the passive
character of perception. The challenge then becomes how to account for the seemingly
passive and uncontrolled nature of dreaming. Here, a common move is to say that
dreams, like imaginings but unlike percepts, are not actively controlled, but are
nonetheless subject to the will (Ichikawa, 2009) or even the product of unconscious
authorship involving a psychic split between the dream self, or the audience of the dream,
and the dream producer (McGinn, 2009). There are numerous issues in the background,
and this is not the place to enter into this debate in any detail (but see Windt, 2015a,
Chapter 6); but it is noteworthy that the imagination view construes the relationship
between dreaming and control in a way that is diametrically opposed to the claim that
dreaming is a spontaneous, uncontrolled process.
Spontaneous Thought, Insight, and Control in Lucid Dreams
Page 47 of 49
PRINTED FROM OXFORD HANDBOOKS ONLINE (www.oxfordhandbooks.com). (c) Oxford University Press, 2015. All Rights
Reserved. Under the terms of the licence agreement, an individual user may print out a PDF of a single chapter of a title in
Oxford Handbooks Online for personal use.
Subscriber: OUP-Reference Gratis Access; date: 14 April 2018
(4.) A particularly interesting question is whether thoughts experienced within a dream
are experienced as spontaneous or as deliberately caused. Do we experience ourselves, in
other words, as cognitive agents in our dreams? A related question that is only beginning
to be explored is whether phenomena such as thought insertion and auditory verbal
hallucinations, which are frequent in schizophrenia and are likely related to a disturbance
in agency, exist in dreams. See Rosen (2015) for discussion.
(5.) It is also possible, however, that similar temporal patterns exist for spontaneous
waking thoughts as well. Older research indicates the existence of a circadian rhythm in
spontaneous, task-unrelated thoughts (Giambra & Rosenberg, 1989), and there may also
be a general association between mind-wandering, sleep quality, and chronotype
(Carciofo et al., 2014).
(6.) Interestingly, Fox et al. (2014) found a mild positive bias in all studies on mind-
wandering, regardless of whether recordings were collected in the laboratory or at home.
Further investigating this question in relation to dreaming might shed light on the
complex relationship between mind-wandering and well-being (Franklin et al., 2013; Ruby
et al., 2013).
(7.) One way of understanding this study, consequently, is that it sets out from the folk-
psychological distinction between lucid and non-lucid dreams—as measured by what
participants score as a lucid dream—and seeks to render it more precise by identifying
those factors that most strongly distinguish lucid and non-lucid dreams. The reasoning
behind this approach is that this will lead to a theoretical account of lucidity that is both
theory-driven and empirically plausible—and that, because of its grounding in folk
psychology, is also likely to match participants’ understanding. This last point is
important because lucid dream research, as is the case for all dream research, is
constrained, for methodological reasons, by dream reports (Windt 2013, 2015a).
(8.) Unless indicated otherwise, all of these examples are unpublished reports from the
experiments described in Voss and colleagues 2009, 2013.
(9.) This is strikingly reminiscent of a finding that when participants are asked to imagine
famous persons, visual images of individuals from the black-and-white media era, such as
Albert Einstein, are also experienced as less colored (Pearson & Hollings 2013).
(10.) The observation that lucid dream control often brings about unintended effects also
fits in well with findings on thought suppression in wakefulness. In the white-bear effect
(Wegner et al., 1987; Wegner & Zanakos 1994), attempting to control one’s thoughts by
suppressing certain types of thought contents ironically enhances exactly those kinds of
thoughts one wanted to avoid—for instance, white-bear thoughts. The effect has also
been investigated for sleep-onset imagery. In one study, participants often dreamed about
persons they had been asked to not think about before sleep—and they were more likely
do so than participants who had been asked to think about the target person (Wegner et
al., 2004). In another study, suppressed thoughts seemed to occur in exactly those
Spontaneous Thought, Insight, and Control in Lucid Dreams
Page 48 of 49
PRINTED FROM OXFORD HANDBOOKS ONLINE (www.oxfordhandbooks.com). (c) Oxford University Press, 2015. All Rights
Reserved. Under the terms of the licence agreement, an individual user may print out a PDF of a single chapter of a title in
Oxford Handbooks Online for personal use.
Subscriber: OUP-Reference Gratis Access; date: 14 April 2018
contexts that the participants had used as distractors. For instance, one participant had
talked about her parents’ garden to suppress white-bear thoughts during wakefulness. As
she drifted off to sleep, she saw
a picture of cherries with a text column alongside, which resembled a recipe in a
magazine she had read in the afternoon as she explained in the morning interview.
Then, a vision of a myriad of small leaves pervaded her mind, abruptly followed by
an image of a fern in a pot on the white, round table in her parents’ garden. At
this point, the picture of the face of a white bear intruded upon her. (Schmidt &
Gendolla 2008, p. 721)
The resurfacing of suppressed thoughts—including feelings of regret, shame, and guilt—
at sleep onset and in the pre-sleep period may even be associated with disturbed sleep
and insomnia (Schmidt & van der Linden 2009, 2013; see also Schmidt et al., 2011). The
general picture seems to be that when control is relaxed, both before sleep, but also at
sleep onset, unwanted thoughts return. It would be interesting to explore how this is
related to cases in which lucid dream control leads to unexpected or even unwanted
results. A prediction would be that because the maintenance of lucidity and the exercise
of dream control involve a sense of effort, resulting cognitive depletion may actually
foster spontaneous and perhaps even unwanted cognitive processes—including, perhaps,
the total or partial loss of lucidity itself, as well as lucidity lapses (see later discussion).
(11.) In other scenarios, the conclusion that one is awake might even be rational by
waking standards: presumably, dreamers could diligently engage in reality testing, and
the results could consistently but falsely indicate that they are indeed awake. This would
correspond to the classical Cartesian scenario of dream deception.
Jennifer M. Windt
Jennifer M. Windt School of Philosophical, Historical and International Studies
Monash University Melbourne, Australia
Ursula Voss
Ursula Voss Institut für Psychologie Johann Wolfgang Goethe-Universität Frankfurt,
Germany
Spontaneous Thought, Insight, and Control in Lucid Dreams
Page 49 of 49
PRINTED FROM OXFORD HANDBOOKS ONLINE (www.oxfordhandbooks.com). (c) Oxford University Press, 2015. All Rights
Reserved. Under the terms of the licence agreement, an individual user may print out a PDF of a single chapter of a title in
Oxford Handbooks Online for personal use.
Subscriber: OUP-Reference Gratis Access; date: 14 April 2018
... Contrasting views have resulted in different lucid dreaming definitions across studies, for example some including control as a defining characteristic ; see also Horton, 2020) and others dissociation (Voss et al., 2014). These results highlight the difficulty in measuring lucidity and the characteristics that may or may not encompass dream awareness (see also Windt & Voss, 2018), particularly through statements that do not directly probe dream awareness. ...
... Also note that van Eeden's (1913) original description of lucid dreams included dream control elements. Our results warrant future discussion about how control fits into the strict definition of lucid dreaming (see also Horton, 2020;Windt & Voss, 2018). ...
... Our results suggest the possibility that in such situations, lucid dreaming training might induce low levels of lucidity potentially undetectable using a binary lucidity outcome measure. Our semi-lucid interrogations are also in line with others suggesting that not all lucid dreams include dream control Schädlich et al., 2017;Schredl et al., 2018;Stumbrys, Erlacher, Johnson, et al., 2014;Windt & Voss, 2018). But without inducing dream control, how could lucid dreaming therapy be effective? ...
Article
Full-text available
Dream lucidity, or being aware that one is dreaming while dreaming, is not an all-or-none phenomenon. Often, subjects report being some variant of “a little lucid” as opposed to completely or not at all. As recent neuroimaging work begins to elucidate the neural underpinnings of lucid experience, understanding subtle phenomenological variation within lucid dreams is essential. Here, we focus on the variability of lucid experience by asking participants to report their awareness of the dream on a 5-point Likert scale (from not at all to very much). Participants implemented a combination of mnemonic training lucid dream induction methods at home for one week and provided detailed reports about their dream experiences each morning. Consistent with previous research, cognitive induction methods led to about half of participants reporting at least one lucid dream and about half of all dreams including some level of lucidity. However, we also show that induction success rate varies significantly depending on the minimum criteria for lucidity. Participants also reported how much they adhered to specific components of each induction method, and the amount of mnemonic rehearsal during a brief early awake period was predictive of lucidity level. Furthermore, lucidity levels were positively correlated with dream control, dream bizarreness, and next-morning positive affect. Lastly, we asked participants open-ended questions about why they chose particular levels of lucidity. We focus a qualitative discussion on responses to those “semi-lucid” dreams (rated just a little, moderately, or pretty much lucid) to explore why participants rate their dreams as having intermediate levels of awareness. Together, the present study explores the frequency of semi-lucid dreams, what they are, why they might arise, their correlates, and how they impact methodological concerns in lucid dreaming research.
... Concurrent reports might also be possible for aware and intentional mind wandering [54][55][56]. Both proposals raise conceptual questions about the classification of experiences that are to some extent deliberately controlled as spontaneous [57,58]. But irrespective of this issue, it seems clear that for the majority of spontaneous experiences in waking and sleep, only retrospective reports are available, and often even these require prompting the participant to give a report (as in experimental awakenings in the sleep laboratory and probecaught methods in mind-wandering research [27]). ...
... More narrowly, thought can also refer to a subgroup of self-generated mental states characterized by conceptual and quasilinguistic content (as opposed to quasi-sensory imagery in different modalities). For example, while dreaming can be described as thinking in the broader sense [81], in the narrower sense, thought would refer only to cases in which the dream self engages in quasi-linguistic thoughts and musings about the ongoing dream [58]. I prefer to speak of spontaneous thoughts and experiences to emphasize that this a phenomenologically diverse category that comprises both conceptually mediated thoughts (or thoughts in the narrow phenomenological sense) and more imagistic types of experience. ...
... While most mind wandering likely happens outside of our awareness and control, we can become aware that our thoughts and attention are wandering [27] as well as initiate mind wandering intentionally ( [55], but see [57]), as when we allow our minds to wander during a boring meeting. A promising approach could be to compare meta-awareness and control of mind wandering with lucid control dreams [58]. ...
Article
Whether we are awake or asleep is believed to mark a sharp divide between the types of conscious states we undergo in either behavioural state. Consciousness in sleep is often equated with dreaming and thought to be characteristically different from waking consciousness. Conversely, recent research shows that we spend a substantial amount of our waking lives mind wandering, or lost in spontaneous thoughts. Dreaming has been described as intensified mind wandering, suggesting that there is a continuum of spontaneous experience that reaches from waking into sleep. This challenges how we conceive of the behavioural states of sleep and wakefulness in relation to conscious states. I propose a conceptual framework that distinguishes different subtypes of spontaneous thoughts and experiences independently of their occurrence in sleep or waking. I apply this framework to selected findings from dream and mind-wandering research. I argue that to assess the relationship between spontaneous thoughts and experiences and the behavioural states of sleep and wakefulness, we need to look beyond dreams to consider kinds of sleep-related experience that qualify as dreamless. I conclude that if we consider the entire range of spontaneous thoughts and experiences, there appears to be variation in subtypes both within as well as across behavioural states. Whether we are sleeping or waking does not appear to strongly constrain which subtypes of spontaneous thoughts and experiences we undergo in those states. This challenges the conventional and coarse-grained distinction between sleep and waking and their putative relation to conscious states. This article is part of the theme issue ‘Offline perception: voluntary and spontaneous perceptual experiences without matching external stimulation’.
... We seem to know who we are dreaming about, although the objects of our dreams differ strongly from reality (Barrett, 1992). We are oriented in space and know where we are although important landmarks in our dream-environment are missing or altered (Windt and Voss, 2018). Time is no longer a marker of progression, e.g. ...
... Foulkes, 1962), this review focuses on REM sleep dreams only. In accordance with Windt and Voss (2018) we consider dreaming "a state of cognitive deficiency resulting from a loss of critical thought and volition, comparable to pathological wake states such as hallucinations and delusions (p. 387, see also Hobson, 1999;Windt & Noreika, 2011). ...
... 274), research on sleep and dreams has generated an extraordinary fundus of knowledge. Starting with the corroboration of the suspected relation between eye movements and dream activity through Dement and Kleitman in 1957, it has been established that some sort of sleep mentation (for further discussion of the term "sleep mentation" see Nielsen, 2000 andWindt andVoss, 2018) occurs 2 An exception to the impossibility to isochronically experience and report the presence of a dream constitutes lucid dreaming (Hearne, 1978;LaBerge, 1985;Voss et al., 2009) in which the dreamer communicates the presence of conscious thought while it is ongoing through a pattern of eye movements. not only in REM sleep but also during NREM sleep, albeit with lesser recall frequencies from NREM sleep (NREM: approx 53%, REM: approx. ...
Article
Full-text available
REM sleep is a state of desynchronized electrophysiological activity of the brain. It is usually accompanied by mental activity characterized by a succession of complex visual experiences commonly referred to as dreaming. Although REM sleep and dreaming are not implicitly conjoined, when they co-occur, they have a very distinct phenomenology, as, typically, the dream plot is bizarre and incohesive which is mirrored in heightened brain activation coupled with strongly attenuated coherence levels. At the same time, owing to increased limbic system activity, REM sleep dreams are highly emotional. Moreover, concrete emotions are often unrelated to dream events. Nevertheless, REM sleep dreams are often subjectively perceived as story-like and autobiographically meaningful. Indeed, elements of salient life events, attachment figures, and personally relevant emotions, especially trauma, seem to have a higher probability of re-appearing in dreams, albeit the dream plot itself remains highly distorted. This has prompted several theories on the interpretability of dreams, some authors leaning towards dreams reflecting waking mentation, others suggesting complete dissociation between waking and dreaming, both sides not fully accounting for empirical findings. In this review, we provide an overview of recent findings on the factors mediating REM sleep neurophysiology and dream content. As a first step towards integration of conflicting research results, we introduce a testable model (Trace-Spur-model) based on Hebb’ian theory of neural networks, proposing that dream bizarreness is a function of state-related modulations in synaptic strength allowing for hyper-associative mental activity, possibly enabling either a restructuring and integrative consolidation or extinction of learning experiences acquired in waking. In this model, dreams are viewed as phenomenological expressions of this neurophysiologic activity where dream recall allows a fragmentary witnessing of such processes, similar to peeking into an enduring and complex networking system. However, the content of the recollected dream is probably strongly deterred by autobiographical memory bias, favoring those images we can form some sort of association with.
... As a dissociative state in which spontaneous creative constructions of the mind run parallel to metacognitive thoughts, lucid dreaming raises questions regarding our consciousness in the dream (Windt & Voss, 2018). Lucid dreaming shows the subjective experience of consciousness that shapes one's perception of the world. ...
... Likewise, lucidity is subsumed under a demanding cognitive style, such as complexity and flexibility of thought. Thus, lucidity enables a conscious, cognitive and selfreflective process during dreaming(Baird, Mota-Rolim & Dresler, 2019;Blagrove & Hartnell, 2000;Windt & Voss, 2018).Robbins (2011) illustrates a broader theory of synaesthesia and lucid dreaming, incorporating psychoanalytic and sociocultural factors. Beyond cognitive mechanisms, primal mental activity is considered to be a cause of phenomena such as synaesthesia, lucid dreaming and creative expression. ...
... As a dissociative state in which spontaneous creative constructions of the mind run parallel to metacognitive thoughts, lucid dreaming raises questions regarding our consciousness in the dream (Windt & Voss, 2018). Lucid dreaming shows the subjective experience of consciousness that shapes one's perception of the world. ...
... Likewise, lucidity is subsumed under a demanding cognitive style, such as complexity and flexibility of thought. Thus, lucidity enables a conscious, cognitive and selfreflective process during dreaming(Baird, Mota-Rolim & Dresler, 2019;Blagrove & Hartnell, 2000;Windt & Voss, 2018).Robbins (2011) illustrates a broader theory of synaesthesia and lucid dreaming, incorporating psychoanalytic and sociocultural factors. Beyond cognitive mechanisms, primal mental activity is considered to be a cause of phenomena such as synaesthesia, lucid dreaming and creative expression. ...
Article
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.
... In contrast, SoA can be greatly increased in dreaming, which might at times replicate delusions of grandeur (Knowles et al., 2011). Increased SoA is common in lucid dreams (Windt & Voss, 2018) although such dreams are less likely to be delusional (Rosen, 2021b) since lucidity is often associated with increased metacognition and rationality along with increased control (Dresler et al., 2016;Pålsson, 2018). ...
Article
The conscious experiences we have during sleep have the potential to improve our empathetic response to those who experience delusions and psychosis by supplying a virtual reality simulation of mental illness. Empathy for those with mental illness is lacking and there has been little improvement in the last decades despite efforts made to increase awareness. Our lack of empathy, in this case, may be due to an inability to accurately mentally simulate what it’s like to have a particular cognitive disorder. Dreaming can help mitigate these deficits by placing the dreamer directly into a realistic virtual simulation and thus increase their capacity for empathy. Increasing empathy would go some way towards reducing the stigma and discrimination faced by people in this group. Recent work suggests that virtual reality can increase empathy towards a variety of marginalised groups, however, this technology is limited in its ability to simulate mental illnesses such as delusions. Dreams, however, are at times virtual reality delusion simulators. They can replicate, to a reasonable degree, delusions and psychosis, and through these experiences, we can learn ‘what it’s like’ to have these conditions. It is essential that we recognise these experiences for what they are, attempt to remember and reflect on them. Instead of disregarding dreams due to their unusualness and bizarreness, we can learn from these experiences and expand our understanding of the human condition and its many forms.
... 35 However, the 32 Dawes et al. (2020) and Zeman (correspondence). 33 Voss et al. (2018); Windt and Voss (2018) Saunders et al. (2016) include recent meta-analyses and summaries of this work. Here, lucid dreams are characterised by the three dissociable features : (i) the presence of subject insight (a conscious awareness that one is dreaming) (ii) control (manipulation of dream content and narrative) and dissociation from one's dream experience (such as seeing the dream as if it were playing on a screen, or viewing one's self from the outside). ...
Article
Full-text available
Aphantasia is a recently discovered disorder characterised by the total incapacity to generate visual forms of mental imagery. This paper proposes that aphantasia raises important theoretical concerns for the ongoing debate in the philosophy and sci- ence of consciousness over the nature of dreams. Recent studies of aphantasia and its neurobehavioral correlates reveal that the ma- jority of aphantasics, whilst unable to produce visual imagery while awake, nevertheless retain the capacity to experience rich visual dreams. This finding constitutes a novel explanandum for theories of dreaming. Specifically, I argue that the recent dream reports of aphantasics constitute an empirical challenge to the emerging family of views which claim that dreams are essentially imaginative ex- periences, constitutively involving the kinds of mental imagery which aphantasics, ex-hypothesi, lack. After presenting this challenge in the context of Jonathan Ichikawa’s recent arguments for this view, I argue that this empirical challenge may be overcome if the ima- gination theorist abandons Ichikawa’s account of dreaming in favour of a modified version. This involves the claim that dreams are essentially inactive and constitutively involve non voluntary forms of imagination. I conclude with a suggestion for further research which can test the viability of this alternative hypothesis, and move the debate forward.
... Originally, this regional change in frontal activity prompted the suggestion that lucid REM sleep is a hybrid state between sleep and wakefulness (Voss et al., 2009). However, as the phenomenology of lucid dreams is still distinctly dreamlike, including bouts of ad hoc, irrational thinking as well as spontaneous contents and immersion, an alternative is to regard lucidity as a substage of REM sleep (Windt & Voss, 2018). Lucid REM sleep would then be a combination of overall REM-like activation with local wake-like activity in frontal areas. ...
Article
Full-text available
Sleep is phenomenologically rich, teeming with different kinds of conscious thought and experience. Dreaming is the most prominent example, but there is more to conscious experience in sleep than dreaming. Especially in non‐rapid eye movement sleep, conscious experience, sometimes dreamful, sometimes dreamless, also alternates with a loss of consciousness. Yet while dreaming has become established as a topic for interdisciplinary consciousness science and empirically informed philosophy of mind, the same is not true of other kinds of sleep‐related experience, nor is it true of sleep itself. I argue that this is a mistake. Conscious experience in sleep is more diverse than dreaming and we need to explain its different forms as well as the alternation between conscious and unconscious sleep states. We also need to ask how different kinds of sleep‐related experience relate to foundational issues about sleep and wakefulness as well as sleep stages. I survey recent findings and theoretical developments from sleep and dream research to show how the traditional view of sleep and its relation to wakefulness and consciousness is flawed. I then suggest that by refining our frameworks of sleep‐related experiences and sleep staging in tandem, we can work toward a better view. As we are only beginning to understand the diversity of consciousness in sleep, an important aim is programmatic: We need a philosophy of sleep and of consciousness in sleep, not just a philosophy of dreaming, and a future theory of sleep needs to integrate phenomenological considerations with neuroscientific and behavioral evidence. Working toward such a theory will radically transform our understanding of sleep, wakefulness, and our conscious minds.
Article
The dynamic framework of mind wandering (Christoff, Irving, Fox, Spreng, & Andrews-Hanna, 2016) is reviewed and modified through integrating the construct of mindful meta-awareness. The dynamic framework maintains that mind wandering belongs to a family of spontaneous thought phenomena. The key defining feature of mind wandering is ‘spontaneity’ which characterizes the dynamic nature of thoughts in the framework. The argument is made that incorporating the mindful meta-awareness construct modifies the dynamic framework as follows: (1) the framework’s criteria for mind wandering do not hold anymore as meta-awareness changes the relationship between thoughts and constraints, and (2) lucid dreaming can be categorized as unguided thought while at the same time being dependent on deliberate constraints. Finally, the application of this modified framework will be discussed in terms of the treatment of mental disorders related to spontaneous thought alterations, in particular depression and nightmares.
Article
Full-text available
Dreams and psychosis share several important features regarding symptoms and underlying neurobiology, which is helpful in constructing a testable model of, for example, schizophrenia and delirium. The purpose of the present communication is to discuss two major concepts in dreaming and psychosis that have received much attention in the recent literature: insight and dissociation. Both phenomena are considered functions of higher order consciousness because they involve metacognitions in the sense of reflective thought and attempted control of negative emotional impact. Insight in dreams is a core criterion for lucid dreams. Lucid dreams are usually accompanied by attempts to control the dream plot and dissociative elements akin to depersonalization and derealization. These concepts are also relevant in psychotic illness. Whereas insightfulness can be considered innocuous in lucid dreaming and even advantageous in psychosis, the concept of dissociation is still unresolved. The present review compares correlates and functions of insight and dissociation in lucid dreaming and psychosis. This is helpful in understanding the two concepts with regard to psychological function as well as neurophysiology.
Article
Full-text available
In this paper, I discuss the relationship between bodily experiences in dreams and the sleeping, physical body. I question the popular view that dreaming is a naturally and frequently occurring real-world example of cranial envatment. This view states that dreams are functionally disembodied states: in a majority of dreams, phenomenal experience, including the phenomenology of embodied selfhood, unfolds completely independently of external and peripheral stimuli and outward movement. I advance an alternative and more empirically plausible view of dreams as weakly phenomenally-functionally embodied states. The view predicts that bodily experiences in dreams can be placed on a continuum with bodily illusions in wakefulness. It also acknowledges that there is a high degree of variation across dreams and different sleep stages in the degree of causal coupling between dream imagery, sensory input, and outward motor activity. Furthermore, I use the example of movement sensations in dreams and their relation to outward muscular activity to develop a predictive processing account. I propose that movement sensations in dreams are associated with a basic and developmentally early kind of bodily self-sampling. This account, which affords a central role to active inference, can then be broadened to explain other aspects of self- and world-simulation in dreams. Dreams are world-simulations centered on the self, and important aspects of both self- and world-simulation in dreams are closely linked to bodily self-sampling, including muscular activity, illusory own-body perception, and vestibular orienting in sleep. This is consistent with cognitive accounts of dream generation, in which long-term beliefs and expectations, as well as waking concerns and memories play an important role. What I add to this picture is an emphasis on the real-body basis of dream imagery. This offers a novel perspective on the formation of dream imagery and suggests new lines of research.
Article
Full-text available
Study objectives To collect and analyze reports of mental activity across sleep/wake states. Design Mentation reports were collected in a longitudinal design by combining our Nightcap sleep monitor with daytime experience sampling techniques. Reports were collected over 14 days and nights from active and quiet wake, after instrumental awakenings at sleep onset, and after both spontaneous and instrumental awakenings from REM and NREM sleep. Setting All reports were collected in the normal home, work and school environments of the subjects. Participants Subjects included 8 male and 8 female undergraduate students (19–26 years of age). Interventions N/A Measurements and Results A total of 1,748 reports, averaging 109 per subject, were collected from active wake across the day (n=894), from quiet wake in the pre-sleep onset period (n=58), from sleep onset (n=280), and from later REM (n=269) and nonREM (n=247) awakenings. Median report lengths varied more than 2-fold, in the order REM > active wake > quiet wake > NREM ≈ sleep onset. The extended protocol allowed many novel comparisons between conditions. In addition, while spontaneous REM reports were longer than those from forced awakenings, the difference was explained by the time within the REM period at which the awakenings occurred. Finally, intersubject differences in REM report lengths were correlated with similar differences in waking report lengths. Conclusions The use of the Nightcap sleep monitoring system along with waking experience sampling permits a more complete sampling and analysis of mental activity across the sleep/wake cycle than has been previously possible.
Article
Full-text available
The idea that dreaming is a simulation of the waking world is currently becoming a far more widely shared and accepted view among dream researchers. Several philosophers, psychologists, and neuroscientists have recently characterized dreaming in terms of virtual reality, immersive spatiotemporal simulation, or realistic and useful world simulation. Thus, the conception of dreaming as a simulated world now unifies definitions of the basic nature of dreaming within dream and consciousness research. This novel concept of dreaming has consequently led to the idea that social interactions in dreams, known to be a universal and abundant feature of human dream content, can best be characterized as a simulation of human social reality, simulating the social skills, bonds, interactions, and networks that we engage in during our waking lives. Yet this tempting idea has never before been formulated into a clear and empirically testable theory of dreaming. Here we show that a testable Social Simulation Theory (SST) of dreaming can be formulated, from which empirical predictions can be derived. Some of the predictions can gain initial support by relying on already existing data in the literature, but many more remain to be tested by further research. We argue that the SST should be tested by directly contrasting its predictions with the major competing theories on the nature and function of dreaming, such as the Continuity Hypothesis (CH) and the Threat Simulation Theory (TST). These three major theories of dreaming make differing predictions as to the quality and the quantity of social simulations in dreams. We will outline the first steps towards a theory-and-hypothesis-driven research program in dream research that treats dreaming as a simulated world in general and as a social simulation in particular. By following this research program it will be possible to find out whether dreaming is a relatively unselective and thus probably non-functional simulation of the waking world (CH), a simulation primarily specialized in the simulation of dangerous and threatening events that present important challenges for our survival and prosperity (TST), or whether it is a simulation primarily specialized in training the social skills and bonds most important for us humans as a social species (SST). Whatever the evidence for or against the specific theories turn out to be, in any case the conception of dreaming as a simulated world has already proved to be a fruitful theoretical approach to understanding the nature of dreaming and consciousness.
Article
Full-text available
Among the most pressing challenges for dream science is the difficulty of establishing theoretical unification between the various theories, ideas, and findings that have been presented in the literature to answer the question of how it is possible to construct a solid scientific theory with predictive and explanatory power in dream science. We suggest that the concept of “world-simulation” serves as the core concept for a theoretically unified paradigm to describe and explain dreaming. From this general concept, more specific theories of the function of dreaming can be derived, such as the Threat Simulation Theory (TST) and the Social Simulation Theory (SST), as we argued in our target article. We agree with Dresler that these two functions may not be the only functions of dreaming, but we still have grounds to believe that they are the strongest contenders. In our reply we first clarify why the functions of sleep should be considered separately from the functions of dreaming. Second, we outline what a good scientific theory of dreaming should be like and what it should be capable of. Furthermore, we evaluate the current state of simulation theories within this context. To conclude, we propose that instead of a general multifunctional theory of sleep and dreaming, where no hypothesis is excluded, the future progress of dream science will benefit more from opposing, competing and mutually exclusive theories about the specific functions of dreaming. This, however, demands that the opposing theories and their predictions must be risky, clearly formulated, and empirically testable.
Article
Full-text available
Most research on mind-wandering has characterized it as a mental state with contents that are task unrelated or stimulus independent. However, the dynamics of mind-wandering - how mental states change over time - have remained largely neglected. Here, we introduce a dynamic framework for understanding mind-wandering and its relationship to the recruitment of large-scale brain networks. We propose that mind-wandering is best understood as a member of a family of spontaneous-thought phenomena that also includes creative thought and dreaming. This dynamic framework can shed new light on mental disorders that are marked by alterations in spontaneous thought, including depression, anxiety and attention deficit hyperactivity disorder.
Article
Full-text available
The neural mechanisms underlying lucid dreaming have recently been investigated using brain imaging techniques such as electroencephalography and functional magnetic resonance imaging, which produce insightful but merely correlative results. We propose that research on the neurophysiology of lucid dreaming, for instance concerning the exact relationship between the dorsolateral prefrontal cortex and metacognitive insight into the fact that one is dreaming, should be complemented by methods allowing direct causal interference with neural functioning during sleep. To achieve this aim, several stimulation methods are proposed, i.e. transcranial magnetic stimulation, transcranial direct current stimulation, and galvanic vestibular stimulation. Given the broad range of cognitive and metacognitive processing in dreams, which support a continuous view of lucid and nonlucid dreaming, we further propose that certain aspects of dream lucidity and its neural mechanisms can be investigated in so-called ordinary, nonlucid dreams. This would allow for phenomenologically more comprehensive and practically more efficient experiments in this field of dream research. Such experiments would also provide a solid ground for understanding self-consciousness in lucid and non-lucid dreams, as well as for integrating dream research into more general neurophilosophical theories of consciousness and the self.
Article
Nightly transitions into sleep are usually uneventful and transpire in the blink of an eye. But in the laboratory these transitions afford a unique view of how experience is transformed from the perceptually grounded consciousness of wakefulness to the hallucinatory simulations of dreaming. The present review considers imagery in the sleep-onset transition—“microdreams” in particular—as an alternative object of study to dreaming as traditionally studied in the sleep lab. A focus on microdream phenomenology has thus far proven fruitful in preliminary efforts to (i) develop a classification for dreaming’s core phenomenology (the “oneiragogic spectrum”), (ii) establish a structure for assessing dreaming’s multiple memory inputs (“multi-temporal memory sources”), (iii) further Silberer’s project for classifying sleep-onset images in relation to waking cognition by revealing two new imagery types (“autosensory imagery,” “exosensory imagery”), and (iv) embed a potential understanding of microdreaming processes in a larger explanatory framework (“multisensory integration approach”). Such efforts may help resolve outstanding questions about dream neurophysiology and dreaming’s role in memory consolidation during sleep but may also advance discovery in the neuroscience of consciousness more broadly.
Chapter
Over a century ago, William James wrote: “The universal conscious fact is not ‘feelings exist’ and ‘thoughts exist’ but ‘I think’ and ‘I feel’” (James 1890: 226). In other words, central to consciousness is the self-as-observer, what James called ‘the knower.’ As Baars explains, “the self is that which has access to consciousness” (1997: 153). (Also see Dennett, 1978.) The notion of self-as-observer implies dual levels of awareness: The contents of experience (participant perspective) are the object of awareness (observer perspective).
Article
Consciousness is often said to disappear in deep, dreamless sleep. We argue that this assumption is oversimplified. Unless dreamless sleep is defined as unconscious from the outset there are good empirical and theoretical reasons for saying that a range of different types of sleep experience, some of which are distinct from dreaming, can occur in all stages of sleep. We introduce a novel taxonomy for describing different kinds of dreamless sleep experiences and suggest research methods for their investigation. Future studies should focus on three areas: memory consolidation, sleep disorders, and sleep state (mis)perception. Our proposal suggests new directions for sleep and dream science, as well as for the neuroscience of consciousness, and can also inform the diagnosis and treatment of sleep disorders.