Lucid Dream Induction Techniques: A Review

Introduction - What is 'Lucid Dreaming'?

A lucid dream is a dream in which the dreamer is consciously aware that they are dreaming. During a lucid dream, the dreamer can often control, manipulate or influence the content of the dream. Some lucid dreamers are able to naturally (i.e. spontaneously) lucid dream, but it is possible to learn techniques and methods to induce lucid dreaming. 

There have been academic literature reviews which have analysed the effectiveness of various lucid dreaming induction techniques (Stumbrys et al, 2012). This literature review concentrated on 35 separate studies into lucid dreaming - 11 sleep laboratory studies and 24 field studies. Within these studies, 26 used cognitive techniques, 11 used external stimulus and one used the administration of drugs. Stumbrys (2012) state that the methodological quality of the studies was relatively low and none of the techniques proved to be very effective at reliably inducing lucid dreams consistently.

Some lucid dream academics dispute whether awareness of dreaming is enough for lucid dreaming (Gillespie, 1984 & Tart, 1984 & 1985). Tart (1984) states that there is a distinction between dream-awareness dreams and lucid dreams. He argues that lucid dreaming involved the added criterion that the dreamer retains the clarity of their waking consciousness within the dream state. 

Tholey (1983) describes 7 aspects of lucidity:

1. Clarity about the state of consciousness (awareness that the dreamer is dreaming)
2. Clarity about freedom of choice
3. Clarity of consciousness
4. Clarity about waking reality
5. Clarity of perception
6. Clarity about the meaning of the dream
7. Clarity in remembering the dream

Tholey states that 1 - 4 are pre-requisites for lucid dreaming, although many lucid dream experts argue that a basic definition - conscious awareness of dreaming - is sufficient. Lucidity is not an absolute state, but can be better described as a 'continuum' with different degrees of lucidity (Barrett, 1992 & Moss, 1986).

Lucid dreaming has been a known phenomenon since the era of Aristotle, although it was at recently as 1978 that it was scientifically proven by Hearne, and subsequently LaBerge (1980). Since then there have been numerous studies into REM sleep, dreaming and lucid dreaming (i.e. Erlacher & Schredl, 2008a). 

REM sleep is characterised by muscle atonia (paralysis) to prevent the dreamer from acting out their dreams (Hobson, Pace-Schott & Stickgold, 2000). This atonia is controlled by neural structures in the brain, and the exception is eye movements which happen during this stage of sleep, a fact which has been confirmed in studies (Roffwarg et al, 1962). 

Lucid dreamers have access to their waking memories (Erlacher, 2009), it has been possible for them to pre-arrange a pattern of eye movements in advance of entering a lucid dream. When performed in a lucid dream state, these eye movements can be monitored on an EOG, meaning that the dreamer can 'communicate' with a researcher from within the lucid dream state (LaBerge, 1981). When awake, the dreamer can provide a dream report which should correspond the recorded eye movement data  with their dreamed gaze shifts. This means that lucid dreaming can be verified by subjective dream reports and objective EOG data (Dane, 1984; Dresler et al, 2012; Fenwick et al, 1984; Hickey, 1988; Kueny, 1985; Oligivie et al, 1983, Vos et al, 2009 & Watanabe, 2003).

The most frequent types of lucid dreams are DILDs (Dream Initiated/Induced Lucid Dreams), although of course, they can also occur via WILDs (Wake Initiated/Induced Lucid Dreams) (LaBerge, Levitan & Dement, 1986). 

Physiologically, lucid dreams are associated with elevated levels of automatic nervous system activity and higher H-reflex suppression (Brylowski, Levitan & LaBerge, 1989). Recent findings, comparing lucid dreams with non-lucid dreams have found that lucidity is associated with increased EEG 40 HZ activity in the brain, particularly in the frontal and frontolateral regions (Voss et al, 2009). Another recent fMRI study discovered that several areas of the brain (including the pre-frontal cortex, precneous and occipito-temporal cortices) are more strongly activated during lucid dreaming (Dressler et al). This specific activation pattern may explain the higher-order cognitive processes and skills which are involved in lucid dreaming, such as self-assessment, executive function, attention-regulation and behavioural controls (Arnsten & Li, 2005; Fernandez-Duque et al, 2000; Miller & Cohen, 2001 & Schmitz et al, 2004). Lucid dreamer have also been shown to display brain activity in regions connected to first-person perspective, the experience of agency and other self-processing operations (Cavanna & Trimble, 2006).

In a lucid dream, the dreamer must observe and evaluate their present experience to recognise that they are in a dream state. They are then able to take first-person perspective, agency and control to guide their attention and behaviour intentionally in order to control the dream (Kahan & LaBerge, 1994). 

Frequent lucid dreaming is regarded as a rare skill, although studies show that approximately 50% of people will experience at least one lucid dream in their lifetimes and about 1/5 people experience them regularly - i.e. at least once a month (Snyder & Gachanbach, 1988 & Stepansky et al, 1998). 

Children and adults seem to share the same prevalence of lucid dreaming, although children appear to have lucid dreams more frequently (Schredl et al 2012). There are also cross-cultural differences - for example lucid dreaming is less prevalent in Japanese persons according to one study (Erlacher et al, 2008).

Lucid dreaming is a very learnable skill - as demonstrated by the work of LaBerge and a number of practical ways of inducing lucid dreams have been proposed (LaBerge, 1980 & Saint-Denys, 1867/1982). For example, lucid dreaming has been harnessed as a therapeutic tool in many nightmare treatments (Abromovitch, 1995 & Spoormaker et al, 2003). A controlled trial (Spoormaker & van den Bout, 2006) demonstrated that lucid dreaming can decrease the frequency and intensity of nightmares. 

It has also been found that lucid dreaming can be used to enhance and improve motor and cognitive skills and promote creative problem-solving (Erlacher & Schredl, 2010 & Strumbrys & Daniels, 2010). Lucid dreaming has also proven to be a useful way for neuroscientists to explore the mind-body relationship during REM sleep and arguably, should be treated as a discreet and special component of consciousness research (Hobson, 2009). 

In order to utilise the advantages and delights of lucid dreaming and render them more accessible to both academics and the general population, effective and reliable induction techniques need to be established which will serve the increase the frequency of lucid dreaming. Finding genuine frequent lucid dreamers who are willing and able to take part in lucid dream research remains one of the biggest obstacles to furthering empirical studies and academic enquiry into this phenomenon. 

Classification of Lucid Dream Induction Techniques

Lucid dream induction basically means the techniques used to cause or increase frequency of lucid dreaming.

Gackenbach (1985/1986)
Gackenbach classified lucid dreaming induction techniques into 2 main categories:

1. Pre-sleep induction
2. Sleep induction

Pre-sleep induction involves intentional techniques and 'unintentional considerations'. This category of lucid dream induction uses intentional techniques to focus on the present moment (reality checks to reflect on whether the individual is currently awake or dreaming, engaging in activities such as meditation or alpha feedback training etc); or the future (auto-suggestion, post-hypnotic suggestion or dream recall affirmations). Some techniques combine both present and future aspects - i.e. Tholey's combined technique (Tholey, 1983) which includes elements of reflection (present focusing - also known commonly as reality checks) and auto-suggestion (future focusing). 

Unintentional considerations include situations during the waking day (interpersonal interactions, emotions) and individual propensities (field independence, creativity) which are not specifically linked to the phenomenon of lucid dreaming or directly related to the induction of a lucid dream, but increase the likelihood of experiencing a lucid dream. 

Sleep induction involves 2 subcategories: internal and external cues. Internal cues are unusual events or inconsistencies within a dream (dreamsigns) or spontaneous insight which occurs within a dream, alerting the dreamer to the fact they are experiencing a dream and not waking reality. External cues are the various environmental stimuli (auditory, olfactory, tactile) which can be applied during REM sleep, and experienced by the dreamer while they are within a dream state. These 'cues' are incorporated into the dream and allow the dreamer to become aware that they are dreaming.

Prince & Cohen (1988)
Prince & Cohen developed 3 main categories for classifying lucid dream induction techniques:

1. Lucid-awareness training
2. Intention & suggestion techniques
3. Cue REM-minding techniques

Lucid-awareness training involves cultivating a proper waking attitude to promote lucid dreaming, such as critically reflecting on whether one is awake or dreaming (reality checks), heightening perception awareness, alpha feedback or waking fantasy training. 

Intention & suggestion techniques involve triggering lucidity by setting the will or intention to do so. These methods can also be used for improving dream recall or incubating a chosen dream theme, action or narrative. 

REM-minding techniques are similar to Gackenbach's 'external cues' - and involve sensory stimuli applied during REM sleep with the aim of triggering lucidity in the dreamer. 

Some other lucid dream induction methods - such as Tholey's combined method - do not fit into these 3 categories, and neither does hypnagogic techniques (where the dreamer enters the lucid dream at the onset of sleep rather than becoming lucid within a non-lucid dream) and WILD (Wake Initiated/Induced Lucid Dreaming) by which the individual enters a lucid dream state directly from the waking state without any lapse in consciousness. 

The above systems of classification are useful, but fragmentary and non-exhaustive as they fail to cover all types of lucid dream induction technique. Since they were developed, empirical research into lucid dreaming have expanded our knowledge about induction techniques and new methods have emerged (Noreika et al, 2010). Another criticism of the above classification models is that they seem to be based on subjective personal or anecdotal evidence and lacked empirical validation. Some of the categories tend to overlap also - such as Tholey's combined technique.

The following categories may therefore be more useful:

1. Cognitive techniques - lucid awareness training, intention, suggestion, hypnagogic methods
2. External stimuli - acoustic, light, vestibular, olfactory electrical, brain stimulation which are applied during REM sleep too trigger lucidity
3. Miscellaneous techniques - diverse methods not covered  by the first 2 categories - such as ingestion of lucid dream substances

Review of Lucid Dream Induction Techniques

Overall, the methodological quality of studies into lucid dreaming induction techniques has been criticised as 'poor'. This includes both laboratory and field studies. The main criticisms of methodology are that the samples sizes are small and the exact conditions of the studies have significant variability.

Cognitive Techniques
There have been 27 studies (77% of all studies overall) which focus on cognitive lucid dream induction techniques. Within this group of studies, 22 were field studies and 5 were laboratory studies. The following cognitive lucid dream induction techniques were used:

1. MILD Technique (Mnemonic/Memory Induced Lucid Dreaming)
2. Reality Checking/Reflection 
3. Tholey's Combined Technique
4. Auto-suggestion
5. Dream Re-entry
6. Post-hypnotic Suggestion
7. Alpha Feedback

• MILD Technique

Developed by LaBerge in 1980, the MILD Technique requires the dreamer to use memory aids to set an intention to experience a lucid dream. This is the lucid dream induction technique which has been tested empirically the most often - it was applied in 10 studies, 9 of which were field studies, and one of which was undertaken in a laboratory. In the laboratory study (Kueny, 1985), the MILD Technique was used as a control condition. The field studies were conducted by LaBerge, Levitan and their colleagues and displayed low reporting and methodological quality.

However, it does appear that use of the MILD Technique can increase the frequency of lucid dreams (LaBerge, 1988 & Levitan et al, 1992). Despite this fact, statistical analysis shows that the relationship between MILD practice and lucid dreaming to be weak, yet significant. LaBerge and Levitan - in a number of studies - have argued that when using the MILD Technique in the early morning, lucid dreaming tends to occur more frequently following naps. This is known as the Wake-Back-to-Bed method (abbreviated as WBTB or WB2B). They suggest that it is favourable to wake up 30 - 120 minutes before the individual would normally get out of bed, stay awake for the period of 30 - 120 minutes and practice the MILD Technique before taking a nap. It was found that this method had better chances of inducing lucid dreams than when the dreamer woke for 10 minutes and then went back to sleep (so shorter waking periods between sleep and nap) or went back to sleep immediately after waking. The WBTB method (using 30 - 120 minutes of wakefulness) also proved to be more effective than a longer period of wakefulness i.e. 4 hours or wakefulness and then an afternoon nap. 

It was found that the MILD Technique was slightly more effective than using light stimulus during REM sleep, although the combination of both light stimulation and MILD Technique appeared to be more effective than either taken in isolation (LaBerge, 1988 & Levitan & LaBerge, 1994).

• Reality Checking/Reflection

Reality checking/reflection requires the individual to frequently ask themselves whether they are actually dreaming during the waking day. The individual also examines their environment for possible incongruences or inconsistencies which should confirm whether or not they are awake or dreaming (Tholey, 1983).

Reality checking was used in one laboratory study (Dane, 1984) but was not used as an experimental condition. Reality checking was also used in 8 field studies (including: LaBerge, 1988; Levitan & LaBerge, 1994; Malamud, 1979; Purcell, 1988; Reis, 1989 & Schlag-Gies, 1992). However, in one study (Levitan & LaBerge, 1994) there were no reports of relevant findings and in another (Reis, 1989), reality checking was combined with the use of external stimuli, so the data has to be excluded.

It appears that reality checking does increase the likelihood of inducing a lucid dream (Purcell, 1988), although LaBerge (1988) did not find any positive correlation between reality checking and lucid dream frequency. The studies tend to indicate that reality checking may be more effective as a lucid dream induction technique than other cognitive techniques, such as auto-suggestion (Levitan 1989), post-hypnotic suggestion (Purcell et al, 1986) or intention (Schlag-Gies, 1992). However, the comparison between the effectiveness of reality checking and MILD Technique is ambiguous - LaBerge (1988) found that MILD Technique was the more effective lucid dream induction technique, while Levitan (1989) discovered the opposite. 

• Intention

Intention requires the dreamer to intensely imagine themselves within a dream scene just before they fall asleep. They must imagine that they are able to recognise that they are dreaming (Tholey, 1983). Intention as a lucid dream induction technique is quite similar to the MILD Technique, although it does not require the mnemonic/memory component, which is central to the MILD Technique. In MILD, the emphasis is on the ability of the dreamer to remember, whereas in intention techniques, the key is for the dreamer to recognise they are dreaming.

Intention was used in 4 field studies, although 3 of them were not specifically focused on lucid dream induction, but rather on the use of lucid dreaming as a therapeutic tool for sufferers of nightmares. The study which was concerned with lucid dream induction (Schlag-Gies, 1992) compared it with other lucid dream induction techniques.

In the 'nightmare studies', it was found that almost 50% of nightmare sufferers who were taught to lucid dream using the intention technique experienced a lucid dream within 1 - 3 months (Spoormaker & van den Bout, 2006 & Zadra & Pihl, 1997). It was also found that intention is about as effective as auto-suggestion, but less effective than reality checking (Schlag-Gies, 1992).

• Auto-suggestion

Auto-suggestion involves the individual suggesting to themselves that they will experience a lucid dream. This is done while the individual is on the verge of sleep and in a relaxed state (Tholey, 1983). 

There have only been two studies which have assessed the effectiveness of auto-suggestion in lucid dream induction (Levitan, 1989 & Schlag-Gies, 1992). In the 1992 study, auto-suggestion seemed to increase the likelihood of lucid dreaming, but no such effect was found in the earlier 1989 one. Auto-suggestion appears to be less effective than reality checking/reflection techniques, but has similar levels of effectiveness as intention (Schlag-Gies, 1992). Levitan (1989) found that auto-suggestion may be more effective for frequent lucid dreamers who experience at least one lucid dream per month (compared with amateurs/beginners). 

• Tholey's Combined Technique

Tholey's combined technique (Tholey, 1983) incorporates elements of reality checking/reflection, intention and auto-suggestion and involves developing a reflective frame of mind (reflection); imagining being in a dream and recognising the dream state (intention); and suggesting that one will become lucid when they fall asleep (auto-suggestion). This lucid dream induction technique was analysed in 2 field studies (Paulsson & Parker, 2006 & Zadra et al, 1992). These studies were rated as 'moderate' in terms of their methodological quality and they showed that Tholey's combined technique for lucid dream induction can significantly increase the frequency of lucid dreaming, particularly for individuals who have previous experience in lucid dreaming. However, even individuals who did not have any experience lucid dreaming (amateurs/beginners) were found to have more lucid dreams than dreamers who were not exposed to Tholey's combined method - i.e. those in control groups (Zadra et al, 1992). 

• Post-hypnotic Suggestion

Post-hypnotic suggestion involves a hypnotist suggesting that the individual will experience a lucid dream when they next sleep, while that person is under a hypnotic trance. The individual is usually told that they will experience a lucid dream the next night. Post-hypnotic suggestion was explored in 2 laboratory experiments (Dane, 1984 & Galvin, 1993). The overall methodological quality of these studies was rated as 'fair'. In the study by Dane (1984), 14 out of 15 female subjects (who were susceptible to hypnosis) reported experiencing a lucid dream during one night spent in a sleep laboratory, although Galvin's study (1993) failed to replicate these findings.

The results from field studies are also variable and inhomogenous. In one study, it was reported that post-hypnotic suggestion helped to increase self-reflectiveness in dreams and subjects were able to experience at least one lucid dream within a period of 9 weeks (Galvin, 1993). However, a further study did not find any effect during a 3 week experiment (Purcell et al, 1986).

It is noteworthy that in Dane's successful 1984 study, post-hypnotic suggestion resulted in a greater number of NREM (non-REM) lucid dreams than REM lucid dreams.

• Alpha Feedback

There was one study which used EEG biofeedback training (using alpha activity) before lucid dream induction (Ogilvie et al, 1982). This study was conducted on the premise that lucid dreams are associated with high levels of EEG alpha frequency synchronisation. This is the theory behind use of binaural beats for lucid dream induction. The study found that alpha feedback training had no effect on lucid dream induction or REM alpha levels.

• Dream Re-entry

In one study (Levitan, 1991), dream re-entry was explored as a lucid dream induction technique. This is where the dreamer aims to re-enter the dream state immediately after waking from a dream. The individual remains still and focuses their mind on a particular activity (i.e. counting) while falling asleep again. Using this method, the individual should re-enter the dream state without losing conscious awareness - an idea from Tibetan Dream Yoga (Wangyal, 1998), and the ethos of the WILD Technique (Wake Initiated/Induced Lucid Dreams).

The study used two methods of focusing: counting and body awareness. The results showed that dream re-entry was quite successful as a lucid dream induction technique. 43 out of 191 attempts (23%) resulted in a lucid dream and counting was shown to be slightly more effective than body awareness. In the failed attempts, subjects using counting were less likely to fall asleep again, while subjects using body awareness were most likely to fall asleep without dream recall. However, this study was rated as being methodologically 'low'. 

Other Techniques
One study (Hickey, 1988) which was a mixture of field study and laboratory experiments used a combination of methods (MILD Technique, reality checking, dream re-entry etc) to promote lucid dreaming in children aged 10 - 12 years. During a 6 week training programme, 12 out of 13 children reported at least one lucid dream in their home environment (24 lucid dreams in total). In addition 2 out of 4 children experienced a verified lucid dream in a sleep laboratory setting (6 lucid dreams were recorded across 16 nights). However, due to the eclectic, combined approach used, it is impossible to determine exactly which aspects of the lucid dream induction were successful or more effective than others. 

• External Stimulation

There have been 11 studies which have tested the effect of external stimulation to trigger lucid dreaming during REM sleep. There were 7 laboratory studies and 4 field studies, and external stimuli used ranged from light, acoustic, vibro-tactile, electro-tactile, vestibular bodily stimulation and water.

• Light Stimulation (DreamLight, DreamLink & NovaDreamer)

There have been 4 studies into light stimulation as a lucid dream induction techniques - all conducted by LaBerge and his colleagues. One of the studies was a laboratory experiment (LaBerge et al, 1988), while the remaining 3 were field studies. 

The 3 field studies used commercially available specialist devices for producing light stimulation during REM sleep (LaBerge, 1988; LaBerge & Levitan, 1995 & Levitan & LaBerge, 1994). 

In the 1995 study, the methodological quality was rated as 'fair', whereas the other 3 were considered to be 'poor'. It was found that light cues can be successfully incorporated into REM sleep and trigger lucidity (LaBerge & Levitan, 1995 & LaBerge et al, 1988), but there were indications that this lucid dream induction technique may be slightly less effective than MILD, although the combination of both seemed to yield more positive results (LaBerge, 1988 & Levitan & LaBerge, 1994). 

• Acoustic Stimulation

Acoustic stimulation is generally a voice, buzzer or musical tone and this method has been applied in 3 laboratory studies (Kueny, 1985; LaBerge et al, 1981 & Ogilvie et al, 1983) as well as one field study (Reis, 1989). The methodological quality was rated as 'average'. There has been some indication that acoustic stimulation may be effective as a lucid dream induction technique (LaBerge et al, 1981), but this finding was not conclusive (Kueny, 1985 & Reis, 1989). 

One study did not find any difference in using a voice or a musical tone, although it was found that gradually increasing the volume is more effective than using a constant volume (Kueny, 1985). 

It was also found that using acoustic stimulation during REM sleep which has little alpha activity in the EEG may be more effective than during REM when there is high alpha activity (Ogilvie et al, 1983) although an earlier study by Ogilvie et al (1982) found that lucidity may be associated with high alpha EEG activity. 

• Vibro-tactile Stimulation

There has been one field study into vibro-tactile stimulation as a lucid dream induction technique (Reis, 1989). However, the results of the study which showed some effectiveness in inducing lucid dreams when vibro-tactile stimulation was used in combination with acoustic stimulation and/or reality checking/reflection methods was difficult to generalise due to variations in duration of training etc.

• Electro-tactile Stimulation

Electro-tactile stimulation is applied to the wrist and was used in one laboratory study (Hearne, 1983), yielding fairly good results. The study showed that 6 out of 12 subjects who spent one night in the sleep laboratory experienced a lucid dream. A further 2 subjects experienced lucidity, but woke up at signalling and another one became lucid after falsely perceiving stimulation. 

• Vestibular Stimulation

There has been one study into vestibular stimulation (Leslie & Ogilvie, 1996). This involved subjects being rocked at a constant speed while laying in a hammock during REM sleep. The results from the study are not conclusive but it was found that vestibular stimulation may increase dream reflectiveness in early versus late morning REM sleep stages.

• Water Stimulation

There has been one laboratory study into the use of water stimulation as a lucid dream induction technique (Hearne, 1978). Water was splashed onto the face or hand of the subject, but there was no effect on lucid dreaming found. 

• Application of Drugs

In one study (LaBerge, 2004), acetylcholine esterase inhibitors (Donepezil) was administered to subjects to enhance lucid dreaming. There were 2 doses administered - 5mg and 10mg with a placebo used as a control condition. During this study, 9 out of 10 subjects reported one or more lucid dreams in 2 nights when using the drug, and only one subject reported a lucid dream while using the placebo. Donepezil was found to significantly enhance lucidity rate, frequency of sleep paralysis and increased estimated time spent awake during the night. The higher dose was associated with stronger effects, but also seemed to produce some adverse effects (insomnia, nausea and vomiting).

Conclusions

The lucid dream induction techniques used in the above studies can be split into 3 classes: cognitive, external stimulation and drug application. The only studies which have been included in this review are those which were available in publication - there may be other forms of research in these areas which was not published or accessible.

Out of the cognitive techniques, Tholey's combined technique (Tholey, 1983) seemed to be the most promising. Additionally, the MILD Technique - with or without external light stimulation - when practiced in the early morning during a 30 - 120 minute wake-back-to-bed also seemed to be effective at lucid dream induction. Although there was limited empirical study, dream re-entry showed a good success rate in lucid dream induction. The low or moderate methodological quality of these studies should be borne in mind when considering their reliability. 

The effectiveness of auto-suggestion and post-hypnotic suggestion as lucid dreaming induction techniques remains unclear. These may rely on the susceptibility of the individual to hypnosis or suggestion and success in studies may be due to selection criteria.

The association between alpha activity in the EEG during REM sleep and lucid dreaming is interesting, but also unclear and alpha feedback is a complex method for inducing lucid dreaming outside a sleep laboratory. 

Regarding external stimulation, the results of the studies into these forms of lucid dream induction techniques is also ambiguous. Some success in inducing lucid dreams were found when using light or electrical stimulation, but these findings should be treated with caution as the studies led to the development of commercially available lucid dream induction devices and therefore may be biased (i.e. unsuccessful studies not published). In terms of acoustic stimulation, a gradual increase in volume was found to be more effective than using a constant tone and there was some limited success when using vibro-tactile and vestibular stimulation, although not when using water stimulation and these methods of lucid dream induction should be studied further. It was found that in most cases the subject is able to experience a lucid dream after perceiving a pre-arranged external stimulus during REM sleep, but also on occasions when the external stimulation was applied, but not recognised by the subject. It should be noted that when using external stimulation for lucid dream induction, some forms of cognitive preparation may be necessary for the dreamer to recognise the cue. 

While only one form of drug application (Donepezil) was studied, there is indication that other drugs/substances which alter the cholinergic system (i.e. causing an increase of acetylcholine in the brain) such as DMAE (2-dimethylaminoethanol); rivastigmin; galantamine; huperzine etc may be effective in lucid dream induction (Sergio, 1988 & Yuschak, 2006)

In developing a taxonomy of lucid dream induction techniques, cognitive techniques should be broken down into 2 further sub-categories: DILD (Dream Initiated/Induced Lucid Dreams) and WILD (Wake Initiated/Induced Lucid Dreams) (LaBerge & Rheingold, 1990) as these two methods represent very different approaches to lucid dream induction. In DILD, lucidity is initiated from within the dream state (i.e. the dream becomes lucid during a non-lucid dream), whereas in WILD, the dreamer directly enters the lucid dream state from the waking state, from dream re-entry (Levitan, 1991) or after a short period of wakefulness (Tholey, 1983). 

The WBTB method has only been empirically tested in combination with the MILD Technique, but it is thought to perhaps be an effective method for inducing lucid dreaming on its own and is likely to have some degree of success when combined with other lucid dream induction techniques. 

There are a number of lucid dream induction methods which have not been empirically tested, but should be further analysed to rate their effectiveness and reliability, Amongst cognitive techniques, WILD Technique and concentration on hypnagogic imagery or active visualisation (LaBerge & Rheingold, 1990 & Tholey, 1983) warrant further investigation. 

Also, neuroscientific investigation into how lucid dreaming may be induced by exciting various structures or activity of the brain may produce interesting results (Hobson et al, 2000; Karim, 2010 & Noreika et al, 2010).

Overall, it is unfortunate that the methodological quality of many studies into lucid dream induction techniques was poor or low. Variability, selection criteria, effect sizes etc may all have an impact and it is impossible to perform a meta-analysis on the available data to ascertain precise degrees of effectiveness for the lucid dream induction techniques which have been subjected to empirical analysis in these studies. It is very difficult to make comparisons between the lucid dream induction techniques using the available information. 

All studies reviewed lacked external validation. Most subjects were self-selected frequent/experienced lucid dreamers or university students which makes it impossible to generalise the findings of the studies out to the larger population. Indeed, it may be very difficult to conduct a study which is representative of the general population. 

There were also issues with internal validity. The majority of the studies were not blinded for the subjects or those measuring the outcomes and in field studies compliance with procedure was not always strictly observed and therefore unreliable. 

Outcome validity and reliability of outcome measures presented further problems in many of the studies, some of which relied on the subjective judgement of the dreamer as to whether they experienced a lucid dream and some of the reports could be fallacious or exaggerated (Synder & Gackenbach, 1988). Some for of external measures to counteract this would be useful in future studies,

One of the biggest problems for research into lucid dream induction is ascertaining the criterion for successful lucid dream induction. In sleep laboratories, the strict criterion is unambiguous, pre-determined eye movement signalling on the EOG during REM or NREM sleep stages and a dream report received immediately after the subject wakes. In field experiments, there is a dream report, but no ploysomnographic sleep recordings are carried out.

While external (blinded) dream report judges can be used in studies, the validation of lucid dreams is still complicated by the fact that recollection of the dream may be affected by sleep inertia, which is a transitional state between sleep and wakefulness during which the dreamer's cognitive abilities are impaired. This presents problems if the subject does not record the dream immediately upon waking. While eye signalling is an objective test of lucidity, dream reports alone are entirely subjective and leaves the question of verification open-ended. Some critics of lucid dream induction research have pointed out that in the absence of confirmatory dream reports, eye signalling may not always be reliable as  eye movements during REM sleep may coincidentally correspond with the pre-determined eye movements used for signalling. The necessity of confirmatory dream reports is also highlighted by the criticism that it may be ambiguous as to whether the subject is experiencing a lucid dream by eye signals alone given that researchers may have encouraged the subject to signal, even if they are not completely aware of dreaming. It may be that future studies devise a more sophisticated way for the dreamer to communicate with the researcher while experiencing a lucid dream.

Lucidity is often considered an all-or-nothing phenomenon - the dreamer either knows they are dreaming and are lucid, or they do not know they are dreaming and are not lucid. This ignores the fact that there are different levels of lucidity and lucidity is more of a continuum than a binary experience (Barrett, 1992). 

The different levels of lucidity are not accounted for in the lucid dream induction studies, although Purcell (1988) devised a dream self-reflectiveness scale which involves 2 categories: lucidity and control. 

Some researchers use a more specific definition of the minimum criterion for lucid dreaming. Schlag-Gies (1992) only considers a dream to be a lucid dream if some consequence occurs as a result of the realisation that the dreamer is dreaming (i.e, an intention to change the setting of the dream). It is therefore necessary for more complex lucidity scales to be devised in order to discriminate between the different degrees of lucidity and their association with various lucid dream induction techniques. This would allow the comparison of lucid dream induction techniques on both a quantitative and qualitative basis. 

It is also necessary to analyse the differences between laboratory and field study experiments - it has been noted that the environment of the sleep laboratory may act as an additional motivation for the subject to experience a lucid dream. On the other hand, pressure to experience a lucid dream may be counter-productive and cause sleep disruption. 

Researchers should also put a time factor into consideration, given that the studies have shown that the MILD Technique is most likely to be effective when performed in the early morning. This would allow them to explore whether certain technique are more effective at specific times.

The stage of sleep during which the lucid dream occurs should also be taken into consideration. Although the majority of lucid dreams occur during REM sleep and are largely considered to be a form of REM phenomena, they can also occur during NREM sleep. In one study (Dane, 1984) a number of dreams were recorded in NREM1 and NREM2 sleep, but none on NREM3 sleep; and it has been found that self-reflection may even be possible in the deep sleep stage (Mason et al, 1997).

Hobson (2009) proposes that lucid dreaming is a dissociative state which has elements of both waking and dreaming, while LaBerge (2010) states that REM sleep is capable of supporting reflective consciousness. Future research should focus on lucid dreaming during REM and NREM stages of sleep and compare the findings.

Some lucid dream induction techniques work better for some people. For example auto-suggestion was found to be most effective for frequent, experienced lucid dreamers, but have little effect for infrequent lucid dreamers (Levitan, 1989). This may explain why post-hypnotic suggestion may work for those who are susceptible to hypnosis or why MILD may work well for persons with good prospective memories. Therefore, individual difference and level of lucid dreaming experience should be taken into account in future studies. 

It seems that the 'Golden Age of lucid dream research' was during the 1980s and 1990s - and since then scientific or academic interest in dreaming and lucid dreaming has declined dramatically, although it appears that we are experiencing a newly emerging reawakening in interest in the subject as a result of  contemporary neuroscientific research and a rise in cultural popularity. With the assistance of new brain-imaging technology (Dressler et al, 2011), lucid dreaming may represent an invaluable tool for understanding how the brain works during sleep and the wider issue of the nature of our consciousness.

In order to progress lucid dreaming research and make it available to greater populations, effective and reliable lucid dream induction techniques must be established - and this is likely to be assisted by an increasing public interest in lucid dreaming. 

Lucid Dreaming, Out-of-Body Experiences & Astral Projection (1)

This article concentrates specifically on out-of-body experiences (OBEs). 

I initially intended to upload one single Blog post dealing with both OBEs and astral projection (AP), but it seems more logical and practical to break down the subject into more manageable articles, dealing with different aspects separately so I can cover them in more depth.

So, why am I posting articles on OBEs and AP?

As a Lucid Dream Researcher and general Oneironaut, I am constantly drawn into debates - some individually and others as part of online conversations - about my belief and experience of out-of-body experiences (OBEs) and astral projection (AP). 

I have mentioned elsewhere on this Blog, and will state it again in this article: I do not believe in OBEs or AP. I think these phenomena occur as part of the dream process and people interpret them differently, based on their own perspectives. The one thing with OBEs and APs is that they only seem to happen to people who already have some degree of belief in their existence - a form of confirmation bias. Many lucid dream researchers state that the difference between OBE/AP is that the dreamer experiences them as an actual occurrence in which their mind is awake, but they are not actually dreaming, whereas in a lucid dream, the dreamer must always be consciously aware they are experiencing a dream. I do not believe in the existence of a consciousness which can exist outside of my physical brain/body; a soul or an astral body which can separate from my physical body. I do not believe that the brain/mind/consciousness are separable. The notion that the brain/mind are separate entities is known as Cartesian Dualism, which is a view sanctioned and espoused by the Catholic Church as well as other religions. The alternative view - held by many humanist atheists like myself - in known as Monoism - a belief that the brain is responsible for all our mental activity and our consciousness. Western scientists tend to ascribe to monoism, but describe the brain and mind in different terms to reflect the idea that the brain is the physical locus for the operations of the mind and the mind emerges from the operations of the brain. 

I am not a religious or spiritual person, but because I have a deep passion and academic interest in dreaming and lucid dream, it is often wrongly assumed that I am also a believer in/practitioner of OBEs/APs, as if these things are all intrinsically interlinked. 

Lucid dreaming is a phenomena which has been empirically proven - with OBEs and APs, the position is a little more vague and open to scepticism. I thought I would write some articles about these phenomena to investigate how they compare and contrast to lucid dreaming and also the amount of empirical proof there is for their existence, outside of the easily-found anecdotal evidence from spiritual people who are inclined to accept the possibility without questioning - or just have a personal investment in their belief which means they will not move from their starting position. 

My aim is not to convince anyone or try to persuade them that my view is the right one. It is simply to address the subject matter in a coherent and detailed way because I have previously discussed it in piecemeal and ad hoc ways when the debate has arisen in the middle of a different conversational topic (loosely linked to lucid dreaming).

Out-of-Body Experiences (OBEs)

An OBE is typically described as the sensation of the body floating outside of the physical body, and sometimes the ability to look down on the physical body from outside it (autoscopy). The term was first introduced into popular culture in George M N Tyrrell, Apparitions (1943) and later adopted by researchers such as Celia Green and Robert Monroe. The use of 'OBE' as a term was initially used as an alternative to 'belief-centric' labels such as astral projection, soul travel or spirit walking.

Research has found that OBEs can be triggered by sleep deprivation, dissociative/psychedelic drugs, brain traumas, near death experiences (NDEs), dehydration and electrical stimulation of the brain. Some people claim to be able to deliberately induce an OBE and it is estimated at 1/10 people will experience what they perceive to be an OBE at least once in their lifetimes. Scientists commonly tend to categorise OBEs as dissociative states/conditions caused by psychological or neurological factors.

The closest I have had to what could be termed an 'OBE' on popular definitions, is when I experience a 'false awakening' after inducing sleep paralysis (part of WILD induction of lucid dreaming), While I am inducing the sleep paralysis for WILD, I feel sensations of floating out of my body, although if I fight the onset of sleep paralysis, my body immediately returns to normal. Often when I initiate a WILD lucid dream, I experience a false awakening - the mistaken belief that I have awoken in my bedroom, when in fact I am still asleep and dreaming. Because I have experienced false awakenings throughout my life (naturally, without any attempt to induce a lucid dream or sleep paralysis), I am often lucid, or able to perform a reality check to confirm. I am able to get out of bed, which some people - who are not aware they are in a false awakening - interpret at the separation of an astral body from their physical body. I have never experienced autoscopy - whenever I am in the lucid false awakening state and have looked back to where I was laying in bed, there is nothing there, and my dream body' is not separate from my perception of my physical body. This may be because my subconscious does not project this vision in my dream, due to my strong  belief that OBEs/autoscopy are just elements of the dream, not actual experiences. 

Indeed, spontaneous OBEs tend to occur just before the onset of sleep, often just preceding a lucid dream state. Usually, these spontanous OBEs occur when the sleeper was not in a deep sleep and was on the borderline of wakefulness. The experience is often accompanied by the feeling of sleep paralysis, although in the majority of cases, the sleeper reports that they perceived themselves as being completely awake. This is one of the main differences between reported OBEs and lucid dreams: in the lucid dream state the dreamer is always aware they are asleep and dreaming, which is what defined a lucid dream. In an OBE, the dreamer is often mistakenly convinced that they are awake and not dreaming. 

So, the OBE experience is more 'vivid' than a normal dream state. It is accompanied by feelings of a floating or pulling; a sense of vigour and energy; vibrations; paralysis; and hearing loud noises. Lynne Levitan and Stephen LaBerge suggest that the phenomenon may be caused by the same conditions as sleep paralysis and are associated with the WILD Technique for inducing lucid dreams, although they refute the assumption that OBEs are a form of lucid dream in themselves (Faraday (1976). They conducted some studies and published the results of their research in the journal article, Levitan & LaBerge, 'Other Worlds: Out-of-Body Experiences & Lucid Dreams (1991) NightLight 3(2 - 3), a publication by The Lucidity Institute, which can be accessed by clicking on the red text link.

Astral Projection
The topic of AP (astral projection) will be covered in more depth in a separate article, as promised, but it is relevant to mention this phenomenon here also. Astral projection is the paranormal interpretation of OBEs which suggest the existence of one or more 'astral planes' and the ability of the non-physical 'astral body' to visit these alternative planes of existence, which are beyond the physical. These planes are often referred to as spiritual or etheric planes and can only be experienced if the astral body is able to exit the physical body.

Near-Death Experiences (NDEs)
An NDE is another form of OBE and is experienced during trauma - such as drowning or major surgery. The NDE is characterised by strong subjective experiences of leaving the physical body, and may be linked to visions of religious or dead figures, transcendence of the ego and crossing of spatial-temporal boundaries. NDEs share some common traits: feelings of being dead, but in a state of peacefulness and painlessness; sensations of floating outside and above the physical body (and sometimes autoscopy) visions of a tunnel, lights and God-like entities; hearing non-physical sounds (i.e. sounds not witnessed by persons in close proximity to the physical body of the person experiencing the NDE); having their life reviewed ('whole life flashing before their eyes'); and a reluctance to return to their physical body and normal life. 

OBEs are sometimes accompanied by a sense of bilocation (also known as 'multilocation') which is when it feels like the body is in two different places at once. Bilocation features in many different spiritual, mystical or religious practices, such as Hinduism, Occultism/Magic, New Age, Paganism, Shamanism, Christian and Jewish Mysticism and early Greek philosophies. It is defined as a 'psychic' or 'miraculous' ability. Research has shown that OBEs may occur spontaneously in people who undertake strenuous and demanding physical activities such as high altitude climbing and marathon running. This is often experienced as the sensation of simultaneously observing and feeling events from both the ground and air. 

Induction of OBEs
Drugs/chemicals such as LSD, DMT, MDMA and Ketamine have been linked to increased chances of a person experiencing an OBE. 

OBEs can be mentally induced, much like lucid dreams - and works on the same basis as the Mind Awake/Body Asleep paradox required for initiating a lucid dream using the WILD Technique. This is one of the reasons I suggest an OBE is simply a dream state very similar to what would be a lucid dream - if the dreamer was consciously aware of being asleep and dreaming. OBE practitioners such as Sylvan Muldoon (1903 - 1969); inventor and entrepreneur Thomas Edison (1847 - 1931); and Surrealist artist Salvador Dali (1904 - 1989) - who used the phenomena as part of his paranoiac-critical method for inspiring his art - all describe the induction of an OBE state in similar ways to those who induce lucid dreams via WILD Technique. The induction of OBEs - like WILD lucid dreams - involves remaining at the borderline of the waking/sleep state, which can cause trance-like experiences and the feeling of leaving the physical body. 

This may be because the Mind Awake/Body Asleep paradox required for inducing OBEs and WILD lucid dreams is a form of passive sensory deprivation. Some induction techniques, such as the Golden Dawn 'Body of Light' Technique (The Hermetic Order of the Golden Dawn was a 19th century organisation devoted to the occult, mysticism and paranormal phenomena), use meditation and visualisation methods (also used in WILD Technique for lucid dreaming) to bring about the OBE.

The following is a list of the ways in which OBEs can be mechanically induced:

• Brainwave synchronisation - audio/visual stimulation. Usually by binaural beats which can induce specific brainwave frequency/activity. The Monroe Institute found evidence that the 'body asleep' brainwave (4 Hz - Theta brainwaves) was linked with OBEs. Others have suggested the 'mind awake' (13 - 38 Hz - Beta brainwaves) are capable of causing OBEs. These changes in brainwave frequency - which are also used to induce lucid dreaming, both at home and in sleep laboratories - are usually combined with other induction methods. 
• Sinusoidal wave pulses have been shown to induce OBEs. This effect is compared to the phenomena where certain drum patterns used by Native Americans led to heightened receptivity to experiencing an OBE, when other brain entrainment methods were also in use.
• Magnetic stimulation of the brain - i.e. use of the 'God Helmet' which was developed by Michael Persinger and Stanely Koren to determine the effect of temporal lobe stimulation on creativity and other mental processes.
• Direct stimulation of the vestibular cortex in the brain.
• Electrical stimulation of the temporoparietal junction, an area of the brain which is linked to the experience of OBEs.
• Sensory deprivation through the use of flotation tanks or pink noise which create intense distortion of spatial and temporal reference points. 
• Sensory overload which involves the use of light forms of torture which encourage the brain to shut itself off from sensory input.
• Strong G-Force.
• Equipment which has an effect on proprioception (individual perception)

Paranormal Theories & Explanations

From my personal experience of discussing OBEs with those who claim they experience them, either spontaneously or through induction, it seems that everyone explains them in terms of parapsychology and/or spiritualism, rather than psycho-physiological or medical/neurological causes. The vast majority - if not all - of those who have discussed their OBEs/astral projection with me are interested in lucid dreaming, and typically have some form of spiritual/mystical belief, tending to see the brain/mind issue from the dualistic perspective which supports their personal experiences. I cannot recall a single person who has described an OBE to me and then suggested (or accepted) a psychological or neurological reason for the experience. However, many of the OBE scenarios I have been told could easily have been mistaken false awakenings as they compare to my own experienced of the latter. 

Therefore amongst practitioners of OBEs, the main explanation for the phenomenon seems to be paranormal, spiritual or mystical.

Those who treat OBEs as a parapsychological phenomena - or from an Occultist perspective - disagree that there are physical explanations for OBEs. They suggest that a soul, spirit or subtle body can detach from the physical body and visit distant locations. During the era of popular Victorian Spiritualism, OBEs were known as 'travelling clairvoyance' and Frederic Myers (1843 - 1901) described them as a 'psychical excursion'.

In a study by Edmund Gurney & Frank Podmore, Phantasms of the Living (1886), the authors described cases of OBEs occurring. These studies were heavily criticised by members of the scientific community because the anecdotal reports relied upon lacked any evidential substantiation. 

In 1927, Theosophist, Arthur Powell (1882 - 1969) described OBEs as the 'subtle body' separating from the physical body, which was similar to later theories advanced by Robert Crookall in 1961 and 1965. 

In 1936, Muldoon stated that OBEs were linked to the 'etheric body'. Ernesto Bozzano (1938) gave similar support, in his theory that OBEs were the result of bilocation between the etheric body and the physical body, which was in turn used as an explanation by occultist writers, Ralph Shirley (1938), Benjamin Walker (1977) and Douglas Baker (1979). James Baker (1954) stated that OBEs occur when the 'mental body' enters a 'inter-cosmic region'.

However, the paranormal interpretation of OBEs has not been embraced by all parapsychologists. Gardner Murphy (1961) claimed that OBEs were not far removed from the terrain of general psychology and could be increasingly explained without recourse to the paranormal. 

In April 1977, a female patient ('Maria') of the Harborview Medical Centre, Seattle, USA, claimed that she experienced an OBE during which she left her physical body and floated outside the hospital. She later told her social worker (Kimberly Clark) that she had 'seen' a tennis shoe on a third-floor window ledge on the north side of the building. Clark, who published the account in 1985, went to the stated location and observed the presence of the tennis shoe. This example has been used in parapsychological literature to 'prove' the existence of OBEs. In 1996, Hayden Ebbern, Sean Mulligan & Barry Beyerstein visited the hospital to investigate the report. They placed a tennis shoe in the exact location Maria and Clark had described and found that it was clearly visible from within the building, and specifically by a patient lying in a bed positioned as Maria's would have been. They also found that the shoe was visible from outside the building and suggested that Maria may have heard a comment about the shoe and incorporated it into her OBE, which was accepted as 'truth' by parapsychologists as a result of naivety and wishful thinking.

Psychological Theories & Explanations

Psychology and cognitive science explain OBEs as being a dissociative experience caused by psychological/neurological factors, some of which have been described above. Instead of seeing OBEs are paranormal or spiritual, psychologists typically suggest an OBE is similar to a dream or altered state of consciousness. 

Here are a few of the dominant psychological theories:

• Charles Richet (1850 - 1935) states that OBEs are a form of dream which involve the brains imagination and memory processes. 
• James Hyslop (1854 - 1920) saw OBEs as a phenomenon which occur when the subconscious mind dramatises certain images, creating the strong impression that the person is in a different location. 
• Eugen Osty (1930) claims OBEs were nothing more than a product of the imagination - like a dream. 
• Schmeing (1938) describes OBEs in terms of psycho-physiological explanations.
• George Tyrrell (1953) claims that OBEs are hallucinatory constructs which relate to the subconscious levels of the personality.
• Donovan Rawcliffe (1959) holds that OBEs were linked with psychosis and hysteria - this link between mental health and OBEs was also found by Horowitz (1970) in relation to body image and Whitlock (1978) in relation to depersonalisation.
• Nandor Fodor (1895 - 1964) & Jan Ehrenwald (1974) assert that OBEs are a defence mechanism designed to deal with the threat of death - an imagined and delusional confirmation of immortality and the possession of a soul which is independent of our physical body.
• Donald Hebb (1904 - 1985) & Cyril Burt (1998 - 1971) explain OBEs in terms of body image and visual imagery.
• Graham Reed (1923 - 1989) states that an OBE may be a stress reaction to a painful life event, such as the loss of a loved one.
• John Palmer (1978) claims that OBEs are a response to a body image change which poses a threat to personal identity.
• Carl Sagan (1934 - 1996) & Barbara Honeggar (1983) suggest that OBEs may represent a 'rebirth fantasy' or a reliving of the birth process.
• Susan Blackmore (1978) states that OBEs are a hallucinatory fantasy, characterised by imaginary perceptions, perceptual distortions and delusional perceptions of self (such as possessing no physical body). This view is shared by Ronald Siegel (1980)
• Myers, Austrin, Grisso & Nickeson (1983) suggest that fantasy-proneness and OBEs are linked and that experiencing an OBE may be more likely if the person has a 'fantasy prone personality'. A study conducted by Gow, Lang & Chant (2004) found that subjects who experienced OBEs were more fantasy-prone and displayed a greater belief in the paranormal.
• Harvey Irwin (1985) claims that OBEs involve attentional cognitive processes and somatic sensory activity and he developed a theory of cognitive personality constructs, known as 'psychological absorption' in which the subject becomes entirely absorbed within their own mental imagery and fantasy. OBES in this respect, are characterised by autoscopy, mental dissociation and depersonalisation.
• Stephen LaBerge (1985) describes OBEs in terms of lucid dreaming using the WILD Technique and suggests it shares characteristics of sleep paralysis (see above).
• David Hufford (1989) links OBEs to 'false awakening' or 'nightmare waking experiences' which are accompanied by sleep paralysis ('cataplexy') and hypnagogia. 
• Terrence Hines (2003) claims that OBEs may be spontaneously induced by stimulation of the brain and may be caused by temporary minor brain malfunctions.
• Bunning & Blanke (2005) suggest that OBEs are due to functional disintegration of lower-level multi-sensory processing and abnormal higher-level processing at the temporoparietal junction. Some research has shown that OBEs may relate to mismatches between visual and tactile signals.
• Alejandro Parra (2009) found that OBEs may relate to cognitive-perceptual schizotypy. 
• Richard Wiseman (2011) claims that OBE research into psychological explanations for the phenomena does not provide evidence for the paranormal, nor the existence of a soul. 
• Jason Braithwaite (2011) links OBEs to neural instabilities in the temporal lobes of the brain and errors in the body's sense of self. In 2013, he and his colleagues reported that OBEs may be caused by a temporal disruption in the multi-sensory integration processes.

OBEs & Neurology

There are several physiological explanations for OBEs. OBEs have been induced by stimulating parts of the brain - for example, one study by De Ridder et al (2007) showed that it was possible to simulate an OBE by stimulating the right superior temporal gyrus in a patient. Positron-emission tomography was used by the researchers to identify the regions of the brain affected by this stimulation. The OBE was categorised as an 'OBE-like experience' because the subjects had either never experienced an OBE before, or described the experience in way which lacked the same clarity as normal OBE reports. The subjects were therefore nor qualified to authenticate the experimentally-induced OBE as being an actual OBE. 

Blackmore argues that OBEs occur when the person loses contact with the sensory input from the body whilst remaining conscious. The person maintains a sense of possessing a body, even though no sensory input is perceived from the physical body. The perceived environment may also resemble the actual physical (waking) environment that the person inhabits, but this perception does not come from the senses either. Instead it is a projection of the brains ability to vividly recreate convincing realms, even in the absence of sensory information. This account corresponds to my own experience of false awakenings and lucid dreams induced through the WILD Technique which involve the Mind Awake/Body Asleep paradox. 

HJ Irwin (1985) noted that OBEs tend to occur in situations of very low or high arousal. Celia Green (1968) found that out of 176 subjects, up to 75% were lying down when they experienced an OBE and 12% had considered themselves to be asleep at the point of onset. By contrast, a very small number of her subjects reported experiencing an OBE when under conditions of maximum arousal - such as involvement in a traffic accident, a dangerous fall or childbirth. McCreery (1997) suggests that this paradox may be explained by reference to the fact that sleep may supervene as a reaction to extreme stress or hyper-arousal. He claims that OBEs under conditions of either complete relaxation or hyper-arousal are a form of 'waking dream' or the intrusion of Stage 1 sleep into the waking consciousness.

Olaf Blanke Studies
Olaf Blanke of Switzerland, conducted a series of studies into OBEs. he found that it was possible to reliably induce states which are very similar to OBEs by stimulating a region of the brain known as the right temporal-parietal junction (TPJ) which is where the temporal lobe and parietal lobes of the brain meet. Blanke was able to show that OBEs are associated with lesions in the right TPJ region and can be elicited by applying electrical stimulation to this area of the brain in patients with epilepsy. The subjects of his studies experienced complex somatosensory responses (perception of transformation of the limbs) and vestibular responses (displacement of the entire body). 

In neurologically normal subjects, Blanke was able to prove that conscious experience of the self and body being in the same location at the same time relies on multi-sensory integration in the TPJ and he was able to analyse activation of the TPJ in healthy subjects and how their perspectives related to reports by persons who experience spontaneous OBEs.

Arzy et al conducted a follow-up study which showed that the location and timing of brain activation depended on whether mental imagery is performed with mentally embodied/disembodied self location. With embodied location, there was activation of an area of the brain called the extrastriate body area (EBA), but under disembodied conditions (so, OBEs), there was an increased activation of the TPJ. 

This leads to the conclusion that the TPJ is responsible for spatial awareness/location of the self, and when normal processes are interrupted, an OBE may be experienced. 

In August 2007, Blanke published an article in Science which suggested that the conflicting visual-somatosensory input in virtual reality could result in a dislocation or disruption of the spatial unity between the self and the body. During 'multi-sensory conflict' a subjects felt that a virtual body seen before them was their actual body and 'mislocalized' themselves towards the virtual body, to a position which was outside of their own bodily borders (so, comparable to an OBE). This study indicates the potential for empirically analysing spatial unity and bodily self-consciousness using multi-sensory and cognitive processing of bodily information. 

Henrik Ehrsson Studies
In August 2007, Henrik Ehrsson at the Institute of Neurology, University College, London (now at the Karolinska Institute, Sweden) published his research in Science, which demonstrated the first empirical method for inducing an OBE in healthy subjects. The subjects were seated in a chair and wore two head-mounted video displays, with two small screens over each eye, which show two live videos which are filmed using two cameras positioned side-by-side, two metres behind the subject's head. The video from the camera on the left is presented on the left-hand display and the video from the camera on the right is presented on the right-hand display. The subject experiences this as one 'stereoscopic' (3D) image - of their own back as viewed from the perspective of  'someone' (the cameras) sitting behind them. The researcher then stands beside the subject (in their view) and uses two plastic rods to simultaneously touch the subject's chest (out of view) and the chest of an illusionary body (so, just below the lens of the camera, where the 'chest' would be if the camera were a person). GThe subjects confirmed they had experienced sitting behind their physical body and viewing it from that location - so viewing themselves from the position of the cameras. 

Both Ehrsson and critics of his study stated that the experiment, which created the illusion of the wakeful subject seeing themselves from outside their physical body, fell short of inducing a 'full-blown OBE'. Similar to earlier studies which induce sensations of floating outside the body, Ehrsson's experiment failed to explain how a brain malfunction may cause an OBE. 

Other OBE Studies

The earliest collections of OBEs are attributed to Ernesto Bozzano (Italy) and Robert Crookall (UK). 

Crookall was a spiritualist and collected his OBE reports from niche newpapers, such as the Psychic News, which has led to some critics suggesting that this may account for a large degree of bias in his work. The majority of his cases report the presence of a cord connecting the astral/spirit body and the physical body, whereas Celia Green reports that less than 4% of her subjects experienced the presence of the 'cord' with 80% of them reporting disembodied consciousness or no external body at all. 

Green was the first researcher to undertake an extensive scientific study into OBEs, in 1968. She collected more than 400 written accounts from subjects reporting to experience OBEs, whom she recruited via appeals appearing in the mainstream media, followed up by questionnaires. Her aim was to establish a taxonomy of the different types of OBEs commonly experienced. She classified OBEs as an anomalous perceptual experience or hallucination, but left the question of extra-sensory perception open.

At the first International Forum of Consciousness Research in Barcelona, Spain, 1999, two researchers from the International Academy of Consciousness Research, Wagner Alegretti & Nanci Trivellato presented their preliminary findings on OBEs, which resulted from an online survey of 1,185 internet users who were interested in the subject matter. However, this 'study' was criticised on the basis that it did not use a sample which was representative of the general population. Of the subjects, 85% reported experiencing an OBE; 37% claimed to have experienced 2 - 10 OBEs; and 5.5% claimed to have experienced more than 100 OBEs. Of the subjects who experienced OBEs, 45% reported successfully inducing the experience using a specific induction technique; 62% stated they had also experienced a non-physical flight; 40% stated they experienced self-bilocation/autoscopy; and 38% stated they experienced self-permeability (the ability to pass through solid objects, such as walls). The most commonly reported sensations included floating, falling, repercussions such as myoclonia (jerking awake), sinking, numbness, intracranial sounds, tingling, clairvoyance, oscillation and serenity. 

Another common sensation was temporary of projective catalepsy - which is associated with the state of sleep paralysis. The correlation between sleep paralysis and OBEs was found in Kevin Nelson et al, 'Out-of-Body Experience & Arousal', Neurology (2007), a study which found that people who experience OBEs are also likely to suffer from sleep paralysis. This link was also established by the Waterloo Unusual Sleep Experiences Questionnaire and the work of Richard Buhlman. Both Buhlman's survey and a study by Twemlow, Gabbard & Jones, 'The Out-of-Body Experience: A Phenomenological Typography Based on Questionnaire Responses' The American Journal of Psychiatry (1982) found that up to 85% of subjects who claim to experience OBEs also report hearing loud noises, commonly known as 'exploding head syndrome' (a form of auditory hynagogic hallucination) during the onset of the OBE. 

'Miss Z' Study
In 1968, American parapsychologist Charles Tart conducted a 4-night study in his sleep laboratory using a subject known as 'Miss Z'. Miss Z was attached to an EEG machine and a 5-digit code was placed on a shelf above her bed. On the first 3 nights, Miss Z said she was unable to see the code during an OBE, but on the fourth night, was able to correctly state the 5 numbers. This study has been criticised heavily by psychologist James Alcock (1981) due to its poor controls and the failure to video record the experiment. Martin Gardner (1989) argued that the study is not evidence for the existence of OBEs and suggested that Miss Z waited until Tart was himself asleep, then stood up (with the EEG electrodes still attached) and peeked at the number code on the shelf. This was the same view of Susan Blackmore (1986) who stated that the EEG machine recorded a pattern of interference in Miss Z's brainwave activity which suggested she had climbed up to look at the code on the shelf.

AWARE Studies
In 2001, Sam Parnia, Assistance Professor of Medicine at the New York State University, Stony Brook, investigated OBEs by placing figures of suspended boards, facing the ceiling, but not visible from below. He would be conducting the study using subjects in medical resuscitation - i.e. persons who underwent a NDE (near-death experience) and claimed to float out of their physical bosy towards the ceiling during the NDE. This was intended to prove that only persons who are able to actually leave their physical body and float towards the ceiling could directly identify the targets; if an OBE is a simply psychological phenomenon, the subject not be expected to correctly identify the target figure. Philosopher, Keith Augustine, who critiqued Parnia's study claims that all identification experiments have produced negative results (i.e. fail to prove the existence of an OBE where the subject left their physical body). British Psychologist. Chris French said that none of the survivor subjects in this study experienced an actual OBE.

In Autumn 2008, 25 British and US hospitals began participating in a study by Parnia and Southampton University, known as the 'AWARE Study' - 'AWAreness during REsuscitation'. This study followed the research of Pim van Lommel, a Dutch doctor and researcher of NDEs. The study analyses the NDE in 1,500 survivors of cardiac arrest and determines whether subjects without a heartbeat or brain activity can have OBEs. The experiment uses hidden targets, placed on a shelf, out of view from below. If none of the subjects can identify the hidden target, then this suggests that OBEs in which the subject claims to have floated out of their physical body are nothing more than illusions or false memories. 

In November 2014, Parnia reported his findings at a conference for the American Heart Foundation. None of the subjects had correctly identified the hidden targets and  only 2 of the 152 subjects reported any visual experiences at all, although one described events which were capable of verification. By 2014, the study was completed and submitted for peer-review for publication in a medical journal.  The results of the AWARE study were published in Resuscitation journal in October 2014. 

Amongst the subjects who reported a perception of awareness during resuscitation and completed further interviews with Parnia and his colleagues, 46% experienced a broad range of mental recollections (in relation to death) which were not compatible with the accepted definition/terms of a NDE. Some of these included fearful or persecutory experiences. Only 9% of the subjects reported experiences compatible with NDEs; and 2% experienced the levels of full awareness compatible with OBEs. These subjects had explicit memories of 'seeing' and 'hearing' events. One case was validated and timed using auditory stimuli during the subjects's cardiac arrest. According to Parapsychologist, Caroline Watt, the one verifiable case reported during the Parnia study was not part of the objective test, because the subject did not actually fulfil the required task of correctly identifying the visual hidden target during his resuscitation, he instead correctly reported events happening in the hospital while he was being resuscitated, such as describing the defibrillator machine noise. However, this in itself was not concrete proof of anything, as it is likely that a large number of people are familiar with typical events in an emergency room from watching medical scenes in programmes/movies. 

The Nancy Penn Center at The Monroe Institute, Virginia, USA, is a facility which specialises in the induction of OBEs. Other facilities which specialise in OBE induction and research are the Center for Higher Studies of the Consciousness, in Brazil; the Projectarium at the International Academy of Consciousness, Portugal; and Olaf Blanke's Laboratory of Cognitive Neuroscience.

* Smith & Messier Study (2014)
Research by Canadian scientists at the University of Ottawa, has recently been conducted into the case of a female subject (a 24 year old Psychology graduate) who is able to experience OBEs at will. She reported that she developed the ability as a child and associated it with difficulties in falling asleep. In particular, she reported that if would often happen during 'sleep time' at pre-school, when she performed it as a distraction while bored and unable to take a nap like her classmates. These OBEs became less frequent as they continued into adulthood. She reported being able to see herself rotating in the air above her body, lying flat and rolling in the horizontal plane. Sometimes she would watch herself move from above, but was always aware of her motionless 'physical body' and experienced no particular emotions linked to these OBEs. She always assumed that everyone could do this.

This study, which was published in the Frontiers in Human Neuroscience journal (2014), terms OBEs as 'extra-corporeal experiences' (ECEs) and found that brain functional changes in this state were different from those observed in motor imagery. 

Smith & Messier used functional magnetic resonance imaging (FMRI) to analyse the subject's brain. She is believed to be the first person observed who is able to experience OBEs at will, without suffering from any brain abnormalities. The researchers founds that there was a strong deactivation of the visual cortex. The brain was activated on the left side of the brain (are areas linked with kinesthetic imagery) and involved some areas which overlapped with the TPJ, which is the region of the brain associated with OBEs. There was also activity in the cerebellum, which was consistent with the subject's report of having the impression of movement during the OBE; and further other brain activity linked to the process of action monitoring. 

The researchers suggest that it may be a common incidence, which often goes unreported because people able to experience these OBEs assume they are normal and unexceptional. They also state that OBEs like these may be more common in childhood, but are not continued into adulthood without regular practice. You can read the full published journal article of Smith & Messiers, 'Voluntary out-of-body experience: an fMRI study' (2014) Frontiers of Human Neuroscience by clicking on the red text link.

In conclusion, I was sceptical before I wrote this article, and confused now I have finished this part of my research. I accept that OBEs are not confined to spiritual and mystical beliefs and that there are certain neurological states which are associated with this phenomenon, which can be tested in empirical studies. I tend to believe that OBEs are an experience which is either the same - or very similar - to those experienced in WILD lucid dreams and sleep paralysis, as I can use my own self-reported experiences in this regard to compare with other research by experts such as LaBerge, and this would suggest they are a psychological illusion akin to a lucid dream, as opposed to the actual detachment of the consciousness from the physical body. However, the latest, highly-publicised study by Smith & Messiers (2014) does raise more questions, which will hopefully be probed and answered in future research.

* Related Articles:
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