Joe Griffin and Ivan Tyrrell (the originators of the human givens approach) define hypnosis as "any artificial way of accessing the REM state, the same brain state in which dreaming occurs" and suggest that this definition, when properly understood, resolves "many of the mysteries and controversies surrounding hypnosis". They see the REM state as being vitally important for life itself, for programming in our instinctive knowledge initially (after Dement and Jouvet) and then for adding to this throughout life. They explain this by pointing out that, in a sense, all learning is post-hypnotic, which explains why the number of ways people can be put into a hypnotic state are so varied: anything that focuses a person's attention, inward or outward, puts them into a trance.
Braid worked very closely with his friend and ally the eminent physiologist Professor William Benjamin Carpenter, an early neuro-psychologist who introduced the "ideo-motor reflex" theory of suggestion. Carpenter had observed instances of expectation and imagination apparently influencing involuntary muscle movement. A classic example of the ideo-motor principle in action is the so-called "Chevreul pendulum" (named after Michel Eugène Chevreul). Chevreul claimed that divinatory pendulae were made to swing by unconscious muscle movements brought about by focused concentration alone.