Deeper into the neuroscience of hypnosis

A new article from Trends in Cognitive Sciences explores how cognitive neuroscientists are becoming increasingly interested in understanding hypnosis and are using it to simulate unusual states of consciousness in the lab.

Hypnosis was typically treated with suspicion by mainstream cognitive science, although an important turning point came when a 2000 study demonstrated that people hypnotised to see colour on grey panels showed activity in the colour perception areas of the brain.

Myths about hypnosis are still common, but it is nothing more than a participant’s willing engagement in a process of suggestion. The hypnotic induction, sterotypically the counting backwards and the ‘you are feeling sleepy’ patter, helps but is not necessary.

Crucially, and for reasons that are still unclear, we all vary in our hypnotisability. This characteristic is known to be more stable than IQ, and normally distributed, like many other psychological traits.

In other words, we can all experience the relaxation and focus, and we can all imagine what the ‘hypnotist’ is suggesting, but only more highly hypnotisable people experience the suggestions as involuntary, as if they’re happening ‘by themselves’.

Recent research has suggested that highly hypnotisable people can disengage the process that looks out for rival demands on our attention, from the process that allows us to focus on which of the competing tasks we need to home in on.

In other words, in highly hypnotisable people, suggestions to experience things contrary to everyday reality may be able to take effect because the normal detect and disentangle mechanism has been temporarily suspended.

Combined with carefully crafted suggestions, this ability allows researchers to simulate certain mental states and experiences in the lab.

For example, hypnotically suggested paralysis, blindness or loss of feeling have been used to simulate the symptoms of ‘hysteria’ or conversion disorder, a condition where neurological symptoms appear without any damage to the nervous system being present.

Other studies have used hypnosis to simulate the feeling that the body is being controlled by outside forces, a common symptom in psychosis, or where a patient thinks their reflection in the mirror is another person, a delusion called mirror misidentification.

And we covered a fantastic study last year, where researchers used hypnosis to simulated psychogenic amnesia, a loss of memory just for old information despite the fact that the patients have none of the brain damage associated with the classic amnesia syndrome.

This new in-depth article covers research attempting to understand hypnosis itself, and science that uses hypnosis as a lab tool, and is a great introduction to the neuroscience research in this developing area.

Link to article.
Link to DOI entry for same.

Full disclosure: the authors of the article are research collaborators and jolly nice chaps to boot.