Behaviouralism is a form of social explanation in which observed behaviour is stressed rather than the simple description of institutions. In behavioural political science formal political institutions are dissolved into ''systems'' and ''processes''. It is distinct from behaviour­ ism in that it is not a psychological theory about individual behaviour but involves sociological statements about collectivities. 

        The roots of the behaviouralism maybe traced back to the general system theory propounded  by a biologist, Ludwig Von Bertallanty in the 1920. This theory emphasized the unification of the sciences. For the first time, ‘Behaviouralism’ marked a systematic attempt to integrate political science with other behavioral sciences and, therefore, it made deliberate efforts to draw freely from these sciences.    

        In the field of Political Science, the origin of this approach can be traced to the writings of Graham Wallas and Arthur Bentley. These two writers in the early 20  9   th  century, laid emphasis on the informal processes of politics, giving less importance to political institutions in isolation. Charles E. Merriam and G.E.G. Catlin in the 1920 and Harold D. Lasswell in the 1930s stressed this approach. But it gained popularity with the work of America political scientists after the second world war.    

       David Easton laid the foundation of the behavioral movement with certain assumptions and objectives. He regarded eight points as the intellectual foundation stones for the behavioralism: (1) regularies (2) verification, (3) techniques, (4) quantification (5) values, (6) Systematization (7) pure science and (8) integration.  

         The behavior approach focuses on political behavior. It calls for the study of acts, attitudes, preferences and expectations of man in the political context. It lays emphasis on the collection actual behavior of man as a social and political being. Thus, behaviouralism shifts its focus from study of politics from formalism and normative orientations of the legalistic and philosophical schools to political behavior, i.e., the behavior of actual actors in the political field like power – holders and  power – seekers as well as voters. As summarized by Kirkpatrick, the main characteristic of behavioral approach is as follows:

1. It rejects political institutions as the basic unit for research and identifies the behavior of  individuals in political situation as the basic unit of analysis.  

2. It identifies social sciences as ‘behavioral science’ and emphasizes the unity of political science  with the social science, so defined.  

3. It advocates the utilization and development of more precise techniques of observing, classifying  and measuring data and urges the use of statistical or quantification formulations wherever possible.  

4. It defines the construction of a systematic empirical theory as the goal of political science. 

          Though behaviouralism made a break through in the field of political science.  It has been criticized on many fronts. Some of its weakness has been identified as follows;  

1. It is based on a false conception of the scientific methods.  

2. It is based upon a false theory of knowledge as it takes facts alone as real.  

3. With craze for ‘Mad Scientism’ it sacrifices the significance of speculative political theory.

4. It makes political science a handmaid of sociology.  

         This approach has taken a place in Indian politics, some works visualized this concept these  are;   A.H. Somjee (Voting Behaviour and Indian villages 1959); Myron Weiner and Rajni Kothari  (eds). (party systems and election studies 1967).