Ernest Hilgard, who developed the "neodissociation" theory of hypnotism, hypothesised that hypnosis causes the subjects to divide their consciousness voluntarily. One part responds to the hypnotist while the other retains awareness of reality. Hilgard made subjects take an ice water bath. They said nothing about the water being cold or feeling pain. Hilgard then asked the subjects to lift their index finger if they felt pain and 70% of the subjects lifted their index finger. This showed that even though the subjects were listening to the suggestive hypnotist they still sensed the water's temperature.[85] Source Wikipedia