This paper explores the relationship between Stanislavski’s ideas about the inward preparation of the actor and contemporary accounts of human behaviour derived from scientific psychology. The paper first sets out a summary of some of Stanislavski’s key ideas about the behavioural and psychological processes an actor might undergo when developing a role (i.e., the operational processes Stanislavski advocates in order to achieve a particular effect or outcome) and then examines how far current evidence supports the relationship between cause and effect that Stanislavski describes. In doing so, the paper places particular emphasis on Stanislavski’s attempts to activate nonconscious processes in the actor as a means of confronting what he calls ‘forced, conventional untruthfulness’ in stage presentation.