Behavioralism (or behaviouralism) is an approach in political science, which emerged in the 1930s in the United States. It represents a sharp break from previous political science. This is because it emphasized an objective, quantified approach to explain and predict political behavior. It is associated with the rise of the behavioral sciences, modeled after the natural sciences. This means that behavioralism tries to explain behavior with an unbiased, neutral point of view.
Behavioralism seeks to examine the behavior, actions, and acts of individuals – rather than the characteristics of institutions such as legislatures, executives, and judiciaries – and groups in different social settings and explain this behavior as it relates to the political system.
Following the Second World War through until the 1960s, behavioralism was a source of controversy. It was the site of discussion between traditionalist and new emerging approaches to political science. The origins of behavioralism is often attributed to the work of University of Chicago professor Charles Merriam, who emphasized the importance of examining political behavior of individuals and groups rather than only considering how they abide by legal or formal rules.
Prior to the "behavioralist revolution", political science being a science at all was disputed. Critics saw the study of politics as being primarily qualitative and normative, and claimed that it lacked a scientific method necessary to be deemed a science.
Behavioralists used strict methodology and empirical research to validate their study as a social science. The behavioralist approach was innovative because it changed the attitude of the purpose of inquiry. It moved toward research that was supported by verifiable facts. During its rise in popularity in the 1960s and 70s, behavioralism challenged the realist and liberal approaches, which the behavioralists called "traditionalism", and other studies of political behavior that was not based on fact.