This paper investigates the adequacy of socialization and social influence processes in accounting for the development of leisure interests. Data come from intensive interviews (N=40) and structured interviews (N=189) with antique automobile enthusiasts. Four major patterns of entry into this world are identified; the most important of these suggest that interpersonal influence alone cannot explain involvement in such activities. I suggest that Berger's conception of “underinstitutionalization” of the social environment and its subjective correlate, “subjectivization,” provides an explanation for the findings. It is argued that this process may have wider applicability in studying leisure activity and social participation, and constitutes a form of social-structural effect that is distinct from socialization and social influence.