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.

The ideomotor phenomenon is a psychological phenomenon wherein a subject makes motions unconsciously. Also called ideomotor response (or ideomotor reflex) The ideomotor phenomenon is a psychological phenomenon wherein a subject makes motions unconsciously. Also called ideomotor response (or ideomotor reflex) and abbreviated to IMR, it is a concept in hypnosis and psychological research. It is derived from the terms "ideo" (idea, or mental representation) and "motor" (muscular action). The phrase is most commonly used in reference to the process wher The ideomotor phenomenon is a psychological phenomenon wherein a subject makes motions unconsciously. Also called ideomotor response (or ideomotor reflex) and abbreviated to IMR, it is a concept in hypnosis and psychological research. It is derived from the terms "ideo" (idea, or mental representation) and "motor" (muscular action). The phrase is most commonly used in reference to the process whereby a thought or mental image brings about a seemingly "reflexive" or automatic muscular reaction, often of minuscule degree, and potentially outside of the awareness of the subject. As in responses to pain, the body sometimes reacts reflexively with an ideomotor effect to ideas alone without the person consciously deciding to take action. The effects of automatic writing, dowsing, facilitated communication, applied kinesiology, and ouija boards have been attributed to the phenomenon. The associated term "ideo-dynamic response" (or "reflex") applies to a wider domain, and extends to the description of all bodily reactions (including ideo-motor and ideo-sensory responses) caused in a similar manner by certain ideas, e.g., the salivation often caused by imagining sucking a lemon, which is a secretory response. The notion of an ideo-dynamic response contributed to James Braid's first neuropsychological explanation of the principle through which suggestion operated in hypnotism. With the rise of Spiritualism in 1840s, mediums devised and refined a variety of techniques for communicating, ostensibly, with the spirit world including table-turning and planchette writing boards (the precursor to later Ouija boards). These phenomena and devices quickly became the subject of scientific investigation. The term ideomotor was first used by William Benjamin Carpenter in 1852. In a scientific paper that specifically discussed the means through which James Braid's "hypnotism" produced its effects, Carpenter derived the word ideomotor from the components ideo, meaning "idea" or "mental representation", and motor, meaning "muscular action". In the paper, Carpenter explained his theory that muscular movement can be independent of conscious desires or emotions; hence the alternative term… I…