Clark L. Hull

By the 1920s, hypnosis became the focus of experimental investigation by psychologists like Clark L. Hull (1884-1952), who demystified hypnosis saying that it was essentially a normal part of human nature. We often go into trance-like states throughout the day but are unaware of it. For example, when we read a book or "zone out" when driving. According to Hull, the important factor was the subject's imagination, and some people were more responsive or "suggestible" than others to hypnosis.