This idea stood in marked contrast to prevalent approaches in the field of comparative politics—the state-society theory and the dependency theory. These were the descendants of David Easton's system theory in international relations, a mechanistic view that saw all political systems as essentially the same, subject to the same laws of "stimulus and response"—or inputs and outputs—while paying little attention to unique characteristics. The structural-functional approach is based on the view that a political system is made up of several key components, including interest groups, political parties and branches of government.