Suggestion is the process whereby a person can influence and guide the thoughts, feelings and behaviour of another person. Emile Coué developed the term suggestion, alongside the emergence of psychology as a science during the nineteenth century. The work of William James used suggestion in order to demonstrate how an idea can bring another idea within the mind. However, the investigation of hypnosis by Clark Leonard Hull, a nineteenth century American psychologist, extended the meaning of suggestion, ultimately separating it from trance. Suggestion is closely connected to hypnosis and the fundamental idea that one a person can induce another into a certain physical or emotional state.