Projective Identification (or PI) is a term first introduced by Melanie Klein of the object relations school of psychoanalytic thought in 1946. It is a concept 'more and more referred to in psychodynamic work', especially in circumstances 'where A experiences feelings that belong to B but that B is unable to access; and instead "projects" them into (not just onto) A'.
Projective identification thus designates a psychological process in which a person engages in the ego defense mechanism projection in such a way that their behavior towards the object of projection invokes in that person precisely the thoughts, feelings or behaviors projected.
Projective identification differs from simple projection in that projective identification is a self-fulfilling prophecy, whereby a person, believing something false about another, relates to that other person in such a way that the other person alters their behavior to make the belief true. The second person is influenced by the projection and begins to behave as though he or she is in fact actually characterized by the projected thoughts or beliefs. This is a process that generally happens outside the awareness of both parties involved, though this has been debated.