An Overview of Classical Behaviorism
Behaviorism is a branch of the science of psychology. It was far and away the most popular psychological perspective during the early part of the twentieth century, first gaining popularity in 1918 with the publication of an article by John B. Watson that outlined the Behaviorist philosophy, and enduring until cognitive psychology gained popular support in the late 1950s.
As a psychological perspective, it holds that observable behaviors are the only phenomena a psychologist should be concerned with, because observation is required for both objective interpretation and measurement. In other words, one can only draw psychological inferences from the behavior a client outwardly demonstrates, without relying upon the analysis of internal processes such as thought and emotions. This was important in the field of psychology because it helped situate the study among the "hard sciences", dealing purely with observable data in an experimental context.
It is extremely important to note, however, that Behaviorists do not reject the existence of internal processes. Many criticize the perspective on this point and are mistaken in doing so. Rather, it is simply that Behaviorists consider these internal events a form of behavior in and of themselves, rather than causes of behavior.