1. any behavior that confirms the moral and adaptive adequacy of the self. See Self-affirmation theory.

2. in psychotherapy, a positive statement or set of such statements about the self that a person is required to repeat on a regular basis, often as part of a treatment for depression, negative thinking, or low self-esteem.

3. in performance or competitive situations, any thought about oneself that is believable and vivid and that reinforces positive characteristics, abilities, or skills.