Harold Garfinkel received his Ph.D. from Harvard University in 1952. He is known primarily as the founder of "ethnomethodology," which focuses on how social actors create and understand the bases of their actions. As a phenomenologist, he has attempted to discover the properties that underlie human communication and social relations. Each actor is seen as creating his or her own social reality based on personal interpretation of the so-called rules that govern relationships. He is a strong advocate of the interactionist perspective in sociology.