other social phenomena. APSA membership rose from 204 in 1904 to 1,462 in 1915. APSA members played a key role in setting up political science departments that were distinct from history, philosophy, law, sociology, and economics. The journal Political Science Quarterly was established in 1886 by the Academy of Political Science. In the inaugural issue of Political Science Quarterly, Munroe Smith defined political science as "the science of the state. Taken in this sense, it includes the organization and functions of the state, and the relation of states one to another." As part of a UNESCO initiative to promote political science in the late 1940s, the International Political Science Association was founded in 1949, as well as national associations in France in 1949, Britain in 1950, and West Germany in 1951. Behavioural revolution and new institutionalism In the 1950s and the 1960s, a behavioral revolution stressing the systematic and rigorously scientific study of individual and group behavior swept the discipline. A focus on studying political behavior, rather than institutions or interpretation of legal texts, characterized early behavioral political science, including work by Robert Dahl, Philip Converse, and in the collaboration between sociologist Paul Lazarsfeld and public opinion scholar Bernard Berelson. The late 1960s and early 1970s witnessed a takeoff in the use of deductive, game-theoretic formal modelling techniques aimed at generating a more analytical corpus of knowledge in the discipline. This period saw a surge of research that borrowed theory and methods from economics to study political institutions, such as the United States Congress, as well as political behavior, such as voting. William H. Riker and his colleagues and students at the University of Rochester were the main proponents of this shift. Despite considerable research progress in the discipline based on all the kinds of scholarship discussed above, it has been observed that progress toward systematic theory has been modest and uneven. 21st century In 2000, the Perestroika Movement in political science was introduced as a reaction against what supporters of the movement called the mathematicization of political science. Those who identified with the movement argued for a plurality of methodologies and approaches in political science and for more relevance of the discipline to those outside of it. Some evolutionary psychology theories argue that humans have evolved a highly developed set of psychological mechanisms for dealing with politics. However, these mechanisms evolved for dealing with the small group politics that