Mapping the Mind - Rita Carter 2010
Dissociation
Mechanisms of Mind
PART I
’Slicing up’ the world like this, into a tiny conscious focal point and an unconscious hinterland, is known as dissociation — the English equivalent of Janet’s disaggregation. Dissociation is used as an umbrella term to cover all sorts of states which involve the separation of various mental processes. It is usually discussed in the context of dissociative disorders — dysfunctional states (such as amnesia and MPD) which, given the problems they cause, are rightly treated as psychiatric illnesses. But dissociation itself is not an illness, or even abnormal. We all filter out of consciousness many or most of the thoughts, feelings and sensations that are being registered at any moment by our brain. Whenever we put something ’out of mind’ such as a nagging worry, an unwelcome emotion or the noise of a road drill when we are trying to work, we are dissociating.
Usually we keep out only those experiences which fall roughly into the category of ’background interference’ — the irritating buzz and hum of city traffic or the meaningless faces of the crowd as we move towards the one familiar one we are seeking. Far from being unhealthy, this sort of everyday dissociation is essential because if our brains did not edit out most of the barrage of information competing for consciousness we would simply be overwhelmed.
Hypnotic induction is a way of producing dissociation on cue. The ease with which a person can be hypnotised generally corresponds to their ability to dissociate spontaneously. Indeed, spontaneous dissociation could be seen as unwitting self-hypnosis.
Hypnotisability is often measured on a scale from 0—5. Grade-5s, those who are most susceptible, make up about 4 per cent of the general population, and the vast majority of people with MPD/DID. A slightly larger proportion of people are Grade 0 — they do not respond at all to hypnotic suggestion. Most people are somewhere between the extremes. A simple way to get a rough idea of a person’s hypnotisability is to see if they can roll their eyes backwards into their head. To perform the eye roll test, tell the subject to:
1 |
Keep his (or her) head steady and look straight ahead. |
2 |
Without moving your head, look upward with your eyes towards your eyebrows, then higher, toward the top of your head. |
3 |
With your eyes held in this upward gaze, slowly close your eyelids. |
4 |
Open your eyelids and let your eyes return to normal focus. |
Hypnotisability corresponds to how much of the iris is visible during the upward gaze. Grade 0s continue to look quite normal, while Grade 5s show barely any iris at all. The eye-roll test was developed by Manhattan psychiatrist Dr Herbert Spiegel in the 1970s and has been found to be almost as good at predicting hypnotisability as the long and complex testing methods used to determine it in a formal psychiatric setting.