Mind Hacks

The Guardian has a short piece and gallery on what couple’s sleeping positions say about their relationship. The article is based on a humorous book called The Secret Language Of Sleep and it’s not quite clear that the writer has picked up on the fact its not meant to be taken too seriously.

The idea that sleep position is linked to personality is surprisingly popular but largely untested. Only poorly controlled study has ever tried to investigate the issue. It chose only 6 out of 14 sleep position recorded from 51 females and concluded that “Sleep positions, particularly the full fetal position, appear to be related to CPI [California Psychological Inventory] variables of Sociability, Sense of Well Being, Achievement by Conformance, Femininity, and Social Maturity”.

The general idea, however, has quite an interesting history. It was originally suggested in passing by the early psychoanalysts and fits well into Freud’s theory of dreaming.

He suggested that when we sleep we are left alone with our unconscious which may contain lots of unpleasant or unwanted desires we don’t want to think about. If we did, we might become so emotionally disturbed as to wake up, therefore, according to Freud, dreams serve to hide our unconscious desires from us by presenting them to us in a more acceptable symbolic form.

From this perspective, dreams serve to keep us asleep and Freud’s big idea was that we can analyse the dream’s ‘manifest’ or obvious content to give us an insight into the ‘latent’ or unconscious meaning. This is why Freud famously wrote that dreams are a “royal road to the unconscious”.

According to Freudian theory, our personalities are largely a reflection of how we manage and ‘defend’ against out our unconscious desires. As our dreaming life occasionally breaks through into movement or speech when we sleep, it’s not a big leap to link sleep position with personality.

This link was made explicitly in a 1979 book called Sleep Positions: The Night Language of the Body by the psychoanalytically inclined psychiatrist Samuel Dunkell. In the book, Dunkell readily admits there is no research to back up his ideas but links personality with sleep position on the basis of individual cases and anecdotes from his own practice, as psychoanalysts have a tendency to do.

Despite being based almost entirely on one man’s opinion, the book has been remarkably influential in pop culture and there has been a steady trickle of media interest ever since that has repeated the main ideas.

In fact, the Huffington Post, which has become an unintentional champion of dodgy science, ran a piece only last week that claimed to explain ‘What Your Sleep Position Says About You’ based almost entirely on Dunkell’s book.

There was a brief media splash in 2003 when sleep psychologist Chris Idzikowski claimed almost exactly the same based on a ‘new study’ but it never appeared and was presumably a PR piece for the private sleep clinic he worked for.

So we don’t really know if sleep position is linked to personality, and certain can’t ‘read’ anything about you from your night-time body position.

But the theory is so popular that even a satirical book can apparently be misinterpreted as supporting the idea.

Link to Guardian piece ‘The politics of sharing a bed’.

While we may have an elaborate dream life as adults, it seems we develop the ability to have rich and vivid dreams as we grow – children start off having relatively simple dreams that become more complex throughout childhood.

Below is an excerpt from a scientific review article on ‘dreaming and the brain’, shortly to be published in Trends in Cognitive Sciences, that addresses how our dream life changes and develops during our early years.

One of the criticisms of these findings might be that dreams seem less complex in younger children because their language isn’t rich enough to describe them fully. However, there is good evidence against this idea – the complexity of dreams is not strongly related to verbal ability, although it is to the vividness of the child’s mental imagery.

When do children start dreaming, and what kind of dreams do they have? Given that children often show signs of emotion in sleep, many assume that they dream a great deal. However, a series of studies by David Foulkes showed that children under the age of 7 reported dreaming only 20% of the time when awakened from REM sleep, compared with 80–90% in adults.

Preschoolers’ dreams are often static and plain, such as seeing an animal or thinking about eating. There are no characters that move, no social interactions, little feeling, and they do not include the dreamer as an active character. There are also no autobiographic, episodic memories, perhaps because children have trouble with conscious episodic recollection in general, as suggested by the phenomenon of infantile amnesia.

Preschoolers do not report fear in dreams, and there are few aggressions, misfortunes and negative emotions. Children who have night terrors, in which they awaken early during the night from SWS [slow-wave sleep] and display intense fear and agitation, are probably terrorized by disorientation owing to incomplete awakening rather than by a dream. Thus, although children of age 2–5 years can see and speak of everyday people, objects and events, they apparently cannot dream of them.

Between the ages of 5‚Äì7 years, dream reports become longer, although they are still infrequent. Dreams might contain sequences of events in which characters move about and interact, but narratives are not well developed. At around 7 years of age, dream reports become longer and more frequent, contain thoughts and feelings, the child’s self becomes an actual participant in the dream, and dreams begin to acquire a narrative structure and to reflect autobiographic, episodic memories.

It could be argued that perhaps all children dream, but some do not yet realize that they are dreaming, do not remember their dreams, or cannot report them because of poor verbal skills. Contrary to these intuitive suggestions, dream recall was found to correlate best with abilities of mental imagery rather than with language proficiency… Put simply, it is children with the most developed mental imagery and visuo-spatial skills (rather than verbal or memory capabilities) that report the most dreams, suggesting a real difference in dream experience.

I’ve removed the numeric references for ease of reading, but you can find the full research sources in the original article.

Link to PubMed entry for article.
Link to DOI entry for same.

Tom alerted me to this fantastic brief case published in the British Medical Journal where a builder is admitted to hospital in great pain after a nail penetrated all the way through his boot. But it turned out that the pain was entirely psychological, as the nail had missed his foot by sliding between his toes.

A builder aged 29 came to the accident and emergency department having jumped down on to a 15 cm nail. As the smallest movement of the nail was painful he was sedated with fentanyl and midazolam. The nail was then pulled out from below. When his boot was removed a miraculous cure appeared to have taken place. Despite entering proximal to the steel toecap the nail had penetrated between the toes: the foot was entirely uninjured.

As Tom mentioned “One of the things I love about it is that the builder had no incentive to ‘fake’. He knew he should have acted tough so we know that the pain he felt wasn’t over-acting. It was imaginary pain, but it was real imaginary pain!”

This isn’t really the nocebo effect, where ‘side-effects’ appear after having taken nothing but a placebo, but more similar to what doctors might describe in its persistent form as somatisation disorder where physical symptoms appear that aren’t explained by tissue damage.

However, both are similar in that real pain arises from beliefs, expectations and perceptions. We now know that all pain has a significant mental component and, consequently, psychological therapy is an effective treatment for chronic pain.

It’s no coincidence that Tom picked up this snippet in a talk by psychologist Stuart Derbyshire who has done some fantastic studies on the neural basis of psychologically controlled and induced pain by using hypnosis in fMRI scanners.

Link to brief piece in the BMJ.

Cognitive Daily covers a super-elegant study that helps us understand whether synaesthesia is really just a case of ‘crossed senses’ or whether the perceptual blending effect requires the person to have processed some of the meaning of the triggering experience.

The traditional explanation of most types of synaesthesia is that the brain’s sensory areas are overly connected, so activation of one sense triggers activity in another area which causes the experience. However, there has been some recent evidence that synaesthesia doesn’t work purely at this basic sensory level.

For example, a recent study by neuropsychologist Jamie Ward and colleagues reported that letter-colour synaesthetes needed to be concentrating on the letters to trigger colours – seeing them ‘out of the corner of the eye’ didn’t work – suggesting there must be some involvement of focus and concentration and not just a reliance on incoming sensory information.

To test the idea further, it would be ideal to be able to separate out experiences where we process just sensory information and experiences where we also understand meaning but as we tend to deal with both at once, this is not easy to do.

But this new study managed to do exactly this in people with colour-speech synaesthesia, where affected people experience colours when they hear specific words, using a perceptual illusion called the McGurk effect.

It’s an intriguing effect that you can see in action on the Cognitive Daily page, but essentially, it shows that seeing someone mouth a word affects what we hear, so if we are played the syllable ‘gah’, but see someone mouthing ‘bah’, the brain makes a compromise and we experience hearing the syllable ‘dah’.

So the effect is a perfect tool to separate out sensory information and meaning, because the researchers can play exactly the same sound but change what word the participants hear simply by showing clips of people mouthing different words.

If colour-speech synaesthesia works only through crossed-senses then the McGurk effect should make no difference to the colours because the exact same sound is played each time, but if this form of synaesthesia is triggered by meaning, the colours should differ because the McGurk effect changes which words are perceived and understood, despite the identical sound.

This is exactly what the researchers found, providing additional evidence that synaesthesia is not just a sensory confusion, it is based in how the brain understands meaning.

It’s an incredibly elegant study and the Cognitive Daily piece covers it equally as elegantly.

Link to CogDaily on ‘Synesthesia and the McGurk effect’.
Link to PubMed entry for study.
pdf of study full text.