In the social sciences, social groups can be categorized based on the various group dynamics that define social organization. In sociological terms, groups can fundamentally be distinguished from one another by the extent to which their nature influence individuals and how. A primary group, for instance, is a small social group whose members share close, personal, enduring relationships with one another (e.g. family, childhood friend). By contrast, a secondary group is one in which interactions are more impersonal than in a primary group and are typically based on shared interests, activities, and/or achieving a purpose outside the relationship itself (e.g. coworkers, schoolmates).