Self-perception

Self-perception theory is an account of attitude change developed by Daryl Bem. It asserts that we only have that knowledge of our own behaviour and its causation that another person can have, and that we therefore develop our attitudes by observing our own behaviour and concluding what attitudes must have caused them.

Self-perception theory differs from cognitive dissonance theory in that it does not hold that people experience a "negative drive state" called "dissonance" which they seek to relieve. Instead, people simply infer their attitudes from their behavior in the same way that an outside observer might.

Reference

Bem, D. I. (1972). Self-perception theory. In L. Berkowitz (Ed.), Advances in experimental social psychology, Vol. 6, pp. 1-62. New York: Academic Press.