Wikipedia
Psychotechnique
Psychotechnique, also known as theatre language, is a rehearsal method developed by Constantin Stanislavsky. The actor would "live life" on stage. Stanislavsky developed a set of exercises and principles designed to help the actor call on personal feelings and experiences, using the body and voice. These elements are used to create the role.
Actors learn to recall emotions from their own lives through the development of self-discipline, observation, meditation/ relaxation, and concentration.