The purpose of sociology is to study human social behavior and the phenomena that interactions between people create, such as social structures, institutions, stratification, and collective behavior. It focuses on modern industrial societies, whereas anthropology focuses on preliterate societies. The sociological imagination allows people to see connections between personal experiences and larger social forces or trends. Early founders of sociology included Auguste Comte, Harriet Martineau, Herbert Spencer, Karl Marx, Emile Durkheim, Max Weber, Jane Addams, and W.E.B. Du Bois. Sociologists use theoretical perspectives like functionalism, conflict theory, and symbolic interactionism to study and understand social phenomena. Common research methods include surveys,