State theory argues that the hypnotic state is a separate state of consciousness, in that it differs significantly from baseline consciousness. State theory suggests that consciousness is divided into various different mental streams and that when an individual is under hypnosis these mental streams move apart from one and other. Hilgard believed that cognition involves these multiple mental streams all being controlled by an “executive ego”. He argues that when under hypnosis there is a division of awareness created by the different mental streams separating them into two therefore allowing the hypnotist to take control of the executive ego. When the different mental streams are split into two, stream one responds to the hypnotist, whilst stream two becomes what Hilgard calls the “hidden observer”. This “hidden observer” is aware of everything taking place and is in a sense conscious however is unable to take control.
There have been many studies carried out to test the predictions made by state theory on hypnosis being an altered state of consciousness. Oakely 1999 believed that during hypnosis the hypnotist hacks into the executive control system, meaning that the persons sense of self awareness is reduced and they lose control of their own decision making process, suggesting that the hypnotist has full control over the individuals executive ego. Rainsville 1999 carried out a study into pain management and hypnosis. He told participants to put their hands in hot water whilst hypnotized. Participants in group one were told it was unpleasantly hot whilst participants in group told it was less hot. PET scans showed that the inner cortex showed correlations with what the participants were told and how they were feeling. This evidence supports state theory as it shows that the hypnotist is in control of the participant’s executive ego allowing the hypnotist to control the participant’s actions.