Delta wave consciousness

Four major kinds of brain waves have been discovered. In terms of cycles per second, the delta waves (1 to 4 cycles) are slowest. They are characteristic of the first 2 hours of normal night sleep and of the deep state of hypnosis. The mind in this condition is said to be most easily programmed by outside stimuli such as post hypnotic suggestion; and the psychic mechanism easily utilized. One researcher (William Condon) refers to six different brain wave frequencies, which include a second delta wave that may be the basic or background rhythm to human behaviour.