Political science is the study of governments, policies, institutions, and the behavior of participants in the political world. Using humanistic and scientific approaches, as well as qualitative and quantitative methods, the field of political science examines political structures both inside and outside government with the goal of better understanding how they function, and the ways in which they change the world over time. The study of political science includes four subfields of specialization: American government and politics, international relations, comparative politics, and political theory.