Science has recently demonstrated that the apparently obvious difference between sleep and wakefulness is far more fuzzy and ill-defined than we ever thought. It is possible to be partly asleep and partly awake in any one of a number of 'near sleep experiences'. It is even possible that parts of our brains may be asleep while others are awake. It is now thought likely that only when 'most' of our brain is asleep do we actually become unconscious. It is likely that we regularly shuffle between different states ranging from fully alert to deep sleep throughout the day and night. Strange experiences are reported by people in intermediate states between sleep and wakefulness which may explain many paranormal reports.

Near sleep experiences are important in understanding many paranormal reports because they produce bizarre experiences, often with apparently paranormal elements, in which dreams appear real. They are also important because they happen to 'normal', healthy people who have no history of illnesses or disorders. These hallucinatory episodes are called REM intrusions - REM is rapid eye movement associated with dreaming. REM intrusion is an episode where elements of dreams are overlaid on observed 'reality', making the experience appear utterly real, because the subject is partly awake and partly dreaming. Hallucinatory content can be visual, auditory or both. There are so many connections between these various types of experience, both in effect and cause, that it is justified to lump them together.

Paul Chambers wrote an excellent article on these, and other phenomena, back in 1999. This articles is intended as an update taking into account new scientific research since then.

Hypnagogia

This is a state that can occur when going to sleep or waking (this latter stage is sometimes distinguished as hypnopompic). During a hypnagogic episode, dream-like elements can intrude into a view of the real world, like a hallucination. See here for more details..

Sleep paralysis

If you have ever woken from sleep to find yourself paralysed, you have probably experienced sleep paralysis which is thought to have affected around 40% of people at least once. As if being paralysed wasn't disturbing enough, some people experience hallucinatory hypnagogic imagery at the same time. Hallucinatory sleep paralysis usually lasts longer than common sleep paralysis, up to around 8 minutes. Some people with sleep paralysis may experience an OOBE (see below). See here for more details.

Microsleep and sleep deprivation

When people are sleep-deprived, as many are these days with busy lives, they can be subject to microsleep. These are periods of a second or two, up to minutes, when someone is not responsive despite often having has their eyes open. It can be difficult to detect both for the experiencer and anyone watching them. During these periods, the experiencer will miss any sensory input. Someone doing a monotonous task, like driving, can also get microsleep. Microsleep is most frequent at times of day when the experiencer would normally be asleep.

For example, if someone was sleep deprived by attending a ghost vigil, they might microsleep during the latter parts of the night. If something in the room changed during a microsleep, they might not notice it happening and assume it had happened paranormally. An object might appear to 'jump' from one place to another when, in reality, it simply fell normally.

People vary enormously in their ability to cope with sleep deprivation. It is now thought possible that, when sleep deprived, parts of our brains may go 'off line' temporarily while we are apparently awake. In this condition we become forgetful or daydream, both of which could result in reports of apparent paranormal activity.

A few people experience brief dream states during microsleep episodes. This could be related to hypnogogia or it may be indicative of a sleep disorder. Either way, it could produce paranormal reports even though the witness appears, and believes themselves to be, fully awake and alert.

OOBE

Out of the body experiences (OOBEs or OBEs) are often seen as paranormal (such as astral projection). However, recent advances in neuroscience are providing an alternative explanation. OOBEs are most often experienced during the near sleep period when waking, particularly if dreaming. Some people get OOBEs while experiencing sleep paralysis.

In a typical OOBE, the subject will find themselves apparently floating outside their body. They often find themselves near the ceiling of the room they are in, looking down on their own body. Naturally, this experience has often been seen as a sort of astral body floating free of the physical one. It is also often part of an NDE or near death experience (see below). It is estimated that 5% of healthy people experience at least one OOBE in their lifetime.

Recent research has shown that there is a part of the brain, called the temporoparietal junction (TPJ) which, if it temporarily behaves unusually for any reason (such as from reduced blood pressure), can lead to OOBEs. The job of the TPJ is to give us an impression of our physical bodies in space, where we end and the 'rest of the world' begins. Since we don't possess motion sensors all over our body, this is an important job without which we would have no sense of how big we are. The TPJ uses sensory information from sight, touch, 'balance' (from the inner ear) and so to create the spatial body image.

It is possible to fool our brains about where our body is fairly easily, giving rise to some strange effects. In the 'rubber hand illusion', for instance, a subject's hand is hidden from view while a rubber one is placed in front of them. If the rubber hand and the subject's real hand are then gently stroked simultaneously, it feels to the subject as though the rubber hand is their own.

An even more interesting experiment can reproduce a full OOBE. Subjects wear a 'virtual reality' head mounted display that shows a TV image of their body from behind. When someone strokes their body, which they can see in their display, they feel as if they are going into the 'body' on the screen.

Whether any OOBEs are paranormal is now down solely to whether they can produce information that could not possibly have been available any other way. It is not enough for someone having an OOBE to report what happened in the room where they were lying because this information could have been deduced by sounds heard during the experience or visual impressions of the room gained while conscious before the experience. Even the viewpoint from the ceiling is not beyond the power of our brains to construct. All sorts of weird viewpoints are constructed during dreams so they could easily be used during similar OOBEs.

Sleep disorders

Though hypnagogia, sleep paralysis, microsleep and OOBE can be experienced by anyone who is perfectly fit and healthy, they could also be symptoms of a sleep disorder or other medical condition. If anyone having these experiences is concerned in any way, they should seek medical advice.

There are various sleep disorders that can produce symptoms similar to or including near sleep experiences. These include narcolepsy, parasomnia, hypersomnia and so on, which are beyond the scope of this article.

NDEs

It has been suggested by some scientists that the striking parallels between OOBEs and NDEs may be more than coincidence. It has been proposed that NDEs may be a particular kind of OOBE that occurs in time of crisis. When our bodies are in a crisis state, near death, they release chemicals that damp down our fear and pain response. This may account for the feeling of euphoria commonly reported in NDEs rather than the fear that often characterises hallucinatory sleep paralysis, for instance.

During NDEs, recordings of brain rhythms with EEGs (electroencephalographs) show flat lines ie. no activity. However, EEGs only record waves from the topmost layers of the brain and REM originates deep inside the brain. Research is ongoing to test these ideas.

Anomalous reports while near sleep

Many reports of anomalous phenomena, like ghosts or alien abductions, involve the witness either about to go to sleep or waking from it (often in bed). It is difficult to eliminate near sleep experiences as the most likely cause of such reports. Often there are odd factors which reinforce the subjective nature of such reports. Not only are bright lights and loud noises (in alien abductions, for instance) not noticed by others in the house but not even by partners sleeping the same bed, who typically remain asleep! Similarly strange, witnesses may simply go back to sleep after their weird experience when, had it been objectively real, that might seem the last thing they would be likely to do. Also, paralysis is frequently reported in alien abduction experiences.

As well as near sleep experiences, some reports from witnesses in bed may be false awakening dreams. Many people have such dreams where they may get up in the normal way, have breakfast and so on, only to later waken for real, feeling disorientated. Such dreams can involve also involve bizarre imagery, including that typical of anomalous phenomena reports.

To show that a report from a witness near sleep was truly objective would require there to be multiple witnesses to the phenomenon or some physical evidence that it had occurred. Otherwise it is virtually impossible to eliminate near sleep phenomena from such cases.

OOBEs when NOT near sleep

Not all OOBEs happen when the subject is near to sleep. Occasionally people can see their surroundings as if from a different viewpoint to the usual 'behind the eyes'. Witnesses do not necessarily see their own bodies. Such 'mini-OOBE's can be triggered by various circumstances. Here is one witness statement:

" I was just walking along when I happened to look down at the brick pathway underfoot. It suddenly appeared to me to be very close, as if I was floating just above it rather than looking from normal walking head height! The illusion quickly broke and I walked off, bemused. "

This mini-OOBE seems to have been triggered by a loss of a sense of depth caused by the highly uniform brick pattern which took up the entire field of view. Subsequent attempts to deliberately reproduce this experience at the same spot have failed. This suggests that knowing what might happen actually inhibits it!

Similar weird experiences have been reported in other situations where judging depth suddenly becomes difficult, such as walking down a motionless escalator. The striped pattern of the metal stairs may be the cause but there is also a weird effect from our brains expecting the stairs to move (see here).

False awakenings

Technically this a a sleep, rather than near-sleep, experience but it can be difficult to tell apart. Someone dreams that they wake up and may do many things before later really waking up (or have a repeat awakening dream). These dreams can be vivid and appear very real even though they contain things that are often wrong, like the surroundings or what happens, compared to a real life awakening.

Some ghost or alien reports may be false awakenings. In particular, there is the inability to wake up other potential witnesses to strange events and the lack of any tangible trace of things that supposedly happened during the 'experience'. Witnesses may also notice things 'wrong' during such 'experiences', such as furniture not in its usual position.

Hypnagogia can also resemble a false awakening.

© Maurice Townsend 2010