Sociology is the scientific study of human society and its origins, development, organizations, and institutions. It is a social science which uses various methods of empirical investigation and critical analysis to develop a body of knowledge about human social activity, structures, and functions. A goal for many sociologists is to conduct research which may be applied directly to social policy and welfare, while others focus primarily on refining the theoretical understanding of social processes. Subject matter ranges from the micro level of individual agency and interaction to the macro level of systems and the social structure. The traditional focuses of sociology include social stratification, social class, culture, social mobility, religion, secularization, law, and deviance. As all spheres of human activity are affected by the interplay between social structure and individual agency, sociology has gradually expanded its focus to further subjects, such as health, medical, military and penal institutions, the Internet, political economy and the role of social activity in the development of scientific knowledge. The range of social scientific methods has also expanded. Social researchers draw upon a variety of qualitative and quantitative techniques. The linguistic and cultural turns of the mid-twentieth century led to increasingly interpretative, hermeneutic, and philosophic approaches to the analysis of society. Conversely, recent decades have seen the rise of new analytically, mathematically and computationally rigorous techniques, such as agent-based modelling and social network analysis. It also includes new areas like Development studies and political economy. Sociology should not be confused with various general social studies courses which bear little relation to sociological theory or social science research methodology.