It's the power of suggestion. If you are willing and able to be hypnotized, you're giving the hypnotist the power to suggest things to you very powerfully. I'm not sure exactly how it works, but when you let yourself fall into a hypnotic trance, you're letting yourself
believe what the hypnotist tells you- up to a point. Hypnotism, contrary to its depiction in cartoons, doesn't completely preclude free will.
ETA: Remember- at one level, things like feeling cold are all in your mind. If you didn't have the neural circuitry to feel changes in temperature, you'd never feel hot or cold at all. So when a hypnotist suggests to your mind that you are cold, you feel it- even if you're in a sauna.
Updated On: 10/14/04 at 11:00 PM