Introspection is a method of reporting the contents or the processes of one's mind.
As a method of psychology, introspection is as old as Plato and Aristotle. Their belief that the mind was really a product of outside stimulation was based upon the experiences of examining their own minds. Wundt and the structural psychologists thought that one could report on the contents of the mind if all experience and bias were removed from the observation. The functionalists essentially agreed with this approach. The Gestalt psychologists also used introspection as a method, but quarreled over whether unbiased observation was either possible or desirable.