Ideomotor signaling: from divining spiritual messages to discerning subconscious answers during hypnosis and hypnoanalysis, a historical perspective.

Ideomotor movements account for non-conscious motions of the hand held pendulum and Ouija board planchette that once were attributed to external spirits. Chevreul and Carpenter in the mid-1800s pioneered our scientific understanding of ideomotor movements. The intention or thought is transmitted to the motor cortex at a subconscious level, coordinated by the cerebellum, and sent down spinal nerves to the appropriate muscles, inducing micromovements not visible to the naked eye but amplified by the hand held pendulum or by the slow ratchet-like cumulative movements of a finger or other body part. This ideomotor phenomenon has been utilized during hypnotic trance to provide nonverbal communication of "yes" or "no" or "I don't want to answer" using finger signals or hand held pendulum. LeCron first used this ideomotor form of communication in conjunction with psychosomatic hypnoanalysis. Cheek expanded and more recently Hammond, Walsh, Ewin and others have refined its use.