Theories of hypnosis
A hypnotic subject may appear to be in a trance. State theorists argue that this is an altered state of consciousness, differing from our normal state as,for example, sleeping does from wakefulness.
The neodissociationist view
The state view held by Ernest Hilgrad (1977) suggests that hypnotic experiences happen because of a dissociation of cognitive systems. The influence of the hypontist separates (dissociates) levels of cognitive processing so that we are aware of cause of our thinking but not others. The ones we are aware of cause hypnotic experiences such as hallucinations, and the suppressed levels account for amnesia, analgesia, etc.
'Reals' versus 'fakers' If hypnosis is a different state, it should be possible to tell the difference between someone who is truly hypnotised ('real') and a 'simulator' who is just 'faking'. In an observation of behaviour when the hypnotist left the room, Evans and Orne (1971) found that hypnotised subjects continued to respond for longer than the simulators. Hypnotised individuals also show a stronger 'post-hypnotic' response (Evans and Orne et al 1968).
Hidden observer Hilgard (1977) suggests that the hidden observer provides access to an otherwise unavailable level of consciousness, i.e. the level that has become dissociated from conscious experience. For example, hypnotic analgesia can be used to mask the pain normally felt when holding a hand in very cold water. When asked if they feel pain, a hypnotised subject says 'no' but the hidden observer reports pain.
Remarkable physical feats have been claimed under hypnosis, such as the response of a hypnotic subject to the suggestion that they are as stiff as a board; they can be placed with only their head and ankles supported and hold themselves still for a long time.
Unique brain states Some aspects of the hypnotic experience are not seen in any other situation, suggesting that hypnosis is a special state. For example, Kosslyn et al (2000) found distinctive brain activity patterns associated with hypnosis and not with other waking states.
This view suggests that hypnotic induction affects behaviours such as relaxation, imagination and compliance, thus making 'hpnotised' individuals behave differently from 'waking' ones.
Socio-cognitive theory of hypnosis (SCT)
According to Graham Wagstaff (1986), hypnotic induction does not result in a different state but it changes two processes: compliance and belief.
Compliance The processes of obedience and conformity are familiar to you from your AS studies by Milgram and Asch. These processes are related to compliance, which describes the behaviour of someone who is conforming/obeying. Compliance refers to situations where a person changes their behaviour (but not their attitudes) to go along with others. In hynosis the subject complies with the expectations of the hypnotist. For example, a hypnotic subject who is offered the suggestion that 'you can feel your arm rising on its own' is likely to oblige (comply) by creating that feeling. Subjects are motivated to comply with such a suggestion to avoid the embarrassment or 'failing' to be hypnotised…