Have you ever had that you were dreaming and you realised you were? And then a lady passes by in your dream and you really don’t like her dog, and when you blink, the dog changes? No? Just me then?

This is an example of a lucid dream: a dream in which you know during the dream that you are dreaming. This ability to ‘wake up’ inside a dream while staying asleep prompts all sorts of interesting questions about sleep, dreams, and ‘altered states’ of consciousness. What does it mean to say that I ‘wake up’ or ‘become conscious’ in a lucid dream? Aren’t you conscious in ordinary dreams? What are dreams anyway? Are they experiences or only stories constructed on waking up?

What is the difference between waking and sleeping?

When we sleep, we all go through a cycle of three states: waking, REM (rapid eye movement) sleep, and non-REM sleep, a typical night’s sleep consisting of four or five cycles between non-REM and REM sleep. These waking and sleep states are defined by physiological and behavioural measures, including how easily the person can be awakened, their eye movements and muscle tone (the degree of passive contraction in the muscle fibres), and their brain activity as measured by either EEG or scans. In REM sleep, the brain is highly active and the EEG resembles that of waking, although paradoxically, the sleeper is harder to wake up than during non-REM sleep. Even in non-REM sleep, the overall firing rate of neurons is as high as in waking states, but the pattern is quite different, with the EEG dominated by long, slow waves rather than complex, fast ones.

The neural systems and physiology of sleep has been well studies and generally considered to be well understood. During sleep, parts of the brain are isolated in different ways and to different extents. Blocking of sensory input happens at the thalamocortical level in nonREM sleep and at the periphery in REM sleep. In REM sleep, the brain stem blocks motor commands at the level of spinal motor neurons so that whatever is going on in motor cortex does not result in physical activity. This means you can dream of climbing out of the window onto the roof, but your legs won’t let you do it – although these protective mechanisms can break down briefly in sleepwalking, and are overactive in sleep paralysis.

When woken from non-REM sleep, people typically say either that nothing was going on in their mind or that they were thinking. As a simple example: ‘I was asleep. I wasn’t thinking about anything or dreaming about anything.’ Or ‘I was thinking about my nephew. It’s his birthday soon and I must send him a card’. Non-REM reports are usually short and lacking in detail. By contrast, when woken from REM sleep, people typically report that they were having complex, much longer, and often bizarre dreams.

If we wake up with a memory of dreaming, we are likely to try to make sense of what we dreamed and this sense-making process is part of the remembering. The natural tendency to attribute significance to dreams was encouraged by Freud’s psychoanalytic approach to dream interpretation, which treats them as forms of wish fulfilment in which the real (or ‘latent’) content, deriving from the unconscious, is disguised in the superficial ‘manifest’ content of the dream scenarios. Jung adapted these ideas to emphasise the role of basic archetypes that represent unconscious attitudes, and can be manifested in various dream symbols and figures which take dynamic forms depending on the dreamer and the dream context. Neither of these theories has stood the test of time. Although dream interpretation books and websites offering readymade templates for meaning-making are popular and many people believe their dreams give insight into unconscious beliefs and desires, there is no good reason to think that they do more than reflect current worries or hopes, a creative way of the brain to deal with events and thoughts of the day.

How does physiology link to experience?

Dream research seems to provide a perfect context in which to look for the neural correlates of consciousness. Various physiological, neurochemical, and behavioural variables can be correlated with subjective descriptions of dreams. On the surface, this might suggest the possibility of either reducing the experiences entirely to physical states, or equating the experiential with the physical, leading to the idea of just one combined objective/subjective space mapping and one concept of dreaming sleep, rather than two. This correlation between physiological states and subjective reports has supported decades of productive research into sleep and dreaming, and made it possible to map the three major states (waking, REM sleep, and non-REM sleep) in terms of their physiology. But does this help us to understand subjectivity or avoid the  hard problem?

The best-known attempt at this sort of mapping is probably Hobson’s AIM model (look back to the SoC mapping of Chapter 13) depicting the idea of a unified ‘brain–mind space’. A (activation energy), I (input source), and M (mode, or amine-choline ratio) all change and the process of cycling through the normal sleep stages can be represented by movement from one region of the space to another.

Things may not, however, be this simple. First, there is the obvious point that the map is crude, including only three dimensions, while the reality is much more complicated. Also troublesome is that the correlation between REM and dreaming, while real enough, is not perfect. In the early days of sleep research, REM sleep and dreaming were often treated as equivalent, but subsequently people became more careful in referring either to the physical state or to the reported experiences. Dreaming is reported in about 70–95% of awakenings from REM sleep and roughly 5–10% of non-REM sleep, while mentation of some sort is reported from about 50% of non-REM awakenings.  

Overall, though, it is clear that being physiologically in REM sleep does not guarantee dreaming, and dreaming can occur without the physiological state of REM.

Also, REM can occur when dreaming seems unlikely or even impossible. For example, human foetuses spend about 15 hours a day in REM sleep, yet foetuses cannot have anything like adult dreams because dreaming depends on prior experiences and on highly developed cognitive abilities which unborn babies lack. People with no visual experience, such as those born blind, dream without visual imagery but in words, ideas, and emotions, and in auditory, tactile, gustatory, and olfactory images. These people have plenty of experiences and a rich sense of self. But the new-born baby has neither and thus does not dream, even while it in in REM.

How about animals and further thought?

Sleep in other species also seems likely to be very different from adult human sleep. Reptiles do not have REM sleep, but many birds and mammals do. Bottlenose dolphins, although extremely intelligent, do not seem to, and only one half of their brain sleeps at a time, in two-hour cycles, so they can keep watch for predators and know when to rise to the surface for air. And if that isn’t the most interesting thing I’ve ever heard!?!

REM-like sleep has been observed in cuttlefish though not octopuses. Mice and rats, dogs and cats, monkeys and apes all have REM sleep, and when we see their eyelids flickering or their whiskers twitching we can easily imagine that they are dreaming. But are we right to do so? We can guess, based on what we know of their cognitive abilities, that some of them might be enjoying complex visual and auditory images, perhaps even with narrative structure, but they cannot describe their dreams in words. So we cannot simply assume that REM equals dreaming.

What’s next?

One possibility is that the physiology and the phenomenology can never be reduced to, or equated with, each other; that the fathomless abyss can never be crossed. Another possibility is that with further research, and better understanding of brain states and neurochemistry, we will learn exactly how brain states relate to the experience of dreaming.

So again, there is no answer to this question.

What is interesting is that maybe one day we could be able to deduce people’s dreams from their brain activity. The first steps have already been taken. In the Gallant Lab at the University of California at Berkeley, scientists recorded many hours of fMRI data while people watched videos and created a huge ‘dictionary’ to relate the shapes, edges, and movements in the videos to activity at several thousand points in the viewer’s brain. When they then showed a new video to the same person, they could use the dictionary to reconstruct a recognisable, if fuzzy, version of the video being watched. A similar method has since been applied to people sleeping inside a scanner and woken from REM sleep. By using the recorded data and the detailed dictionary, images of what they were dreaming about could be reconstructed. The computational power required was vast, but the principle has been proven: it should be possible to look at someone’s brain activity and know what they are dreaming about.

Another example of how to connect physiology with experience comes from the dream bizarreness research by Revonsuo and his research group. They argue that three types of bizarreness in dreams can be understood as failures of three types of binding: feature binding, contextual binding, and binding across time. They conclude that ‘more global forms of binding appear much more frequently than those concerned with only local bundles of features’ and relate this to the number of distinct processing modules involved in generating different kinds of dream images . In other words, the harder it is for the brain to construct a certain kind of integrated image, the more likely it is that such an image will fall apart or show bizarre failures of binding during dreams.

This suggests that even the most peculiar of dream features may yield to a study of brain mechanisms during sleep. Even so, we are still relying on correlations, and as with all other aspects of conscious experience, we cannot say with confidence that dreaming and brain states are reducible to each other or are the same thing, nor can we confidently describe them in terms of ‘brain–mind states’.

So are dreams experiences?

Of course dreams are experiences, you might say, and many would agree. There is this general idea that dreams are images and thoughts of things you have experienced. Movies and tv-shows like to imply that our dreams are subconscious messages, that they try to tell us something about ourselves. That in our dreams, we know and understand what is happening, that we are a player in them.

But are we really aware in our dreams? Suppose that I wake from a dream and think, ‘Wow, that was a weird dream. I remember I was trying to get a beer’. At the time of waking, I seem to have been having the dream. Indeed, I am completely convinced that a moment ago I was dreaming of being in the pub, even if the details slip quickly away and I cannot hang onto them, let alone report them all. But there are some serious problems here. Some concern the self. Although I am sure that ‘I’ was dreaming, the self in the dream was not like my normal waking self. This strange dream-self didn’t realise she was dreaming; she accepted that the people and the food kept changing in impossible ways, showed little disgust or surprise at the state of her body, and in general treated everything as though it was real.

Was it then really me who dreamt it? Maybe not – but perhaps this does not matter because there was some kind of phenomenal self in the dream. This gave way to the PSM, the phenomenal self-model. Looking back at chapter 13, you might argue that the experience of the dream was an ASC then, that you were in a different type of consciousness.

French researcher Alfred Maury described a long and complicated dream about the French revolution, culminating in his being led to the guillotine. Just as his head came off, he awoke to find that the headboard had fallen on his neck. After this had happened, he proposed the theory that dreams do not happen in real time but are entirely concocted in the moment of waking up. This theory became popular, perhaps because so many people have the experience of dreaming about a church bell ringing or a wolf howling, only to wake to the sound of their alarm clock. It is also psychologically plausible in the sense that humans are very good at constructing stories and quick at making them up.

But the theory has been proven to be untrue. In the 1950s, people sleeping in the lab were asked to describe their dreams and they gave longer descriptions the longer they had been in REM sleep. Other experiments tried incorporating external stimuli into dreams. When they don’t wake the sleeper they can sometimes influence dream content, allowing dream events to be timed. These results show that dreams take about the same time as would waking events. All this suggests that dreams are not concocted in a flash on waking up, but really do take time.

Dennett (yess this man again, seriously, does he not have anything better to do with his time??) had  a selection of colourful theories playing with the relationship between experience and memory. In the ‘cassette theory of dreams’, the brain holds a store of potential dreams recorded and ready for use. On waking from REM sleep, a ‘cassette’ is pulled out of storage, to match the sound of the alarm clock if necessary, and hey presto, we seem to have been dreaming. In this theory, there are no real dreams. There are no events or images presented ‘in consciousness’, but only recollections of dreams that were never actually experienced. ‘With the cassette theory it is not like anything to dream, although it is like something to have dreamed. On the cassette theory, dreams are not experiences we have during sleep’. It’s weird and vague and there is not a shred of evidence for it.

In relation to everything in this book, the tendency to distinguish conscious from unconscious elements of dreaming remains common and a hot topic for debate.

What are the ‘borders of sleep’?

Strange, dreamlike experiences can happen before we fall asleep or as we are waking up. At these times, when sensory input is reduced, hallucinations are common, and range from simple visual forms or musical notes to sensations on the skin or imagined changes in the location of a limb. These, so to say, are things that happen on the borders of sleep.

Two extreme phenomena on the borders of sleep are sleep terrors and sleep paralysis. These two are interrelated. Paralysis occurs when someone awakes directly out of REM and their muscles are still paralysed to prevent them from acting out their dreams. In the few minutes it takes for the person’s brain to realise they are awake, the person cannot move. This often results in sleep terrors, scary hallucinations that the person cannot escape from because they cannot move.

Another, maybe more common occurrence, is the ‘false awakening’, a dream of having woken up. Sometimes everything looks quite normal and so the dreamer gets on with dressing and eating breakfast until he really wakes up and has to start all over again. Similar, a person might also go to sleep within a dream and thus believe actual time has passed.

What are lucid dreams then?

In a previous chapter we discussed lucid dreaming, so I won’t have to explain what it is. Let’s continue on what we already know.

The shift from ordinary to lucid dreaming has been characterised in many ways. For Hobson, Voss, and colleagues, there is a difference between ‘primary’ and ‘secondary’ consciousness. Primary consciousness is what we have in normal dreams. It is governed by what is immediately present; all we can do is cope with the immediate and constantly changing scenery, rather than influencing the ongoing experience. When we wake up, we enter higher-order consciousness, in which we can plan ahead, reflect on the past, and contemplate the future. When we ‘wake up’ into a lucid dream, they say, ‘part of the brain operates in the primary mode while another has access to secondary consciousness’. But what does it mean for one part of a brain (or brain–mind) to operate in a different mode from another, and to have access to one kind of consciousness or not? Is the primary consciousness the kind of consciousness that animals have? Or is that different too?

Lucid dreams were long considered to not be a part of serious sleep research and were studied only by psychical researchers and parapsychologists. Even in the mid-twentieth century, many psychologists rejected the whole idea, arguing that self-reflection and conscious choice are impossible in dreams, so lucid dreams must really occur before or after sleep, or during micro-awakenings.

They were proved wrong. The breakthrough was made simultaneously and independently by two young psychologists, Keith Hearne at the University of Hull in England, and Stephen LaBerge at Stanford University in California. In REM sleep the voluntary muscles are paralysed, so a dreamer who becomes lucid cannot shout out ‘Hey, listen to me, I’m dreaming’ or even press a button to indicate lucidity. They realised was that dreamers could still move their eyes. In Hearne’s laboratory, Alan Worsley was the first oneironaut (or dream explorer) to signal from a lucid dream. He decided in advance to move his eyes left and right eight times in succession whenever he became lucid and Hearne picked up the signals on a polygraph. He found them in the midst of REM sleep. The signalling method means we no longer have to rely on retrospective verbal report, and so allows us to answer some classic questions about dreams.

How about out-of-body experiences?

An OBE is an experience in which a person seems to perceive the world from a location outside their physical body. This definition is important because it is neutral as to the explanation required. If you feel as though you have left your body, you have, by definition, had an OBE. During an OBE you feel as though ‘you’ have left your body and are floating or flying above it, looking down on the world from this new position.

OBEs are related to three other types of ‘full body illusion’, all resulting from displacement of the body schema. First, ‘autoscopy’ literally means seeing oneself, but in psychiatry refers to experiences of seeing a double or doppelgänger. The person still seems to be inside their own body but sees an extra self, or a person who looks like them, elsewhere. Second is ‘heautoscopy’, an even more confusing experience in which people are uncertain whether they identify with their own body or with the double; they may even alternate between one and the other. Finally there is the ‘sense of presence’ or ‘feeling of a presence’, a powerful feeling that there is someone else close by even if they cannot be seen. This is confusing, I know, and also not super imported. But, it might be useful to remember these terms in case they decide to be sneaky on the exam.

Although an odd experience, OBEs are relatively common, with somewhere between 12% and 20% of people claiming at least one during their lifetime. Those who have them report more psychic experiences and greater belief in the paranormal than others, as well as better dream recall and more frequent lucid dreams, so these things seem to be related.

OBEs have often been dismissed as pathological dissociation, but although in rare cases epilepsy and brain damage can lead to OBEs, the majority are not associated with any pathology. American OBE researchers concluded that their ‘psychological health is generally excellent, ranking with the healthiest groups in the population’. The theories the book presents are all so closely related to theories of consciousness and dualism it would be a waste of time to discuss them. If you want to read about them, check page 423.

And near-death experiences?

Across many ages and cultures, people coming close to death report a consistent set of experiences and tend to be called NDE.

Most NDEs are pleasant and even blissful, but rarer hellish experiences include black voids and nothingness, chattering demons, black pits, naked zombie-like creatures, and other symbols of traditional hell. On some estimates up to 15% of NDEs are hellish, but it is hard to be accurate because people may be keen to forget them and unwilling to talk about them. Interestingly, suicide attempters generally report positive NDEs and are less likely to try to kill themselves again. Highly positive after-effects are common, including greater interest in spirituality and in caring for others, and reduced interest in material belongings or success. These effects can be long-lasting, with NDErs in one study still reporting continued positive changes eight years after their brush with death. Less often NDErs are left depressed and a few find themselves estranged from family and friends by the changes that take place.

Dismissing NDEs as fabrications or wish fulfilment is unreasonable. The similarities across ages and cultures, and the reliability of the findings, suggest that NDEs have something interesting to teach us about death and consciousness. The question is, what? A common reaction, as to OBEs, is that NDEs are proof of dualism – of the existence of a soul or consciousness that operates independently of the brain and can survive death. There are a couple people with an opinion here;

• Kenneth Ring: the experiences ‘point to a higher spiritual world’ and access to a ‘holographic reality’
• Parnia and Fenwick: understanding NDEs will require ‘a new science of consciousness’
• Van Lommel: they are evidence for non-local consciousness or ‘endless consciousness’. 

Exercises

15.1. Think of the last few times you were dreaming. Was it right before you woke up in the morning? Somewhere in the middle of the night? Or did you jerk awake because of a dream? In all these cases, how well were you able to remember the dream? Can you make a realistic assumption on why (not)?