Structuralism, functionalism, and Gestalt psychology all seek to understand human experience by "looking" at mental processes. However, mental processes -- like sensation, perception and cognition -- are internal and cannot be directly observed. They are all examples of the perspective known as mentalism, the study of mental events and processes. Mentalism has long been criticized as a contradiction of the empirical basis of the scientific method. Recall that science relies on empirical (sense experienced) observations of real events. If a researcher cannot see or hear or feel another's thoughts or hidden emotions, these processes cannot be studied scientifically. Behaviorism is the alternative to mentalism.
Behaviorism is a perspective in psychology that emphasizes the need to study only what is observable. Mental events are not observable; behaviours are observable. Thus behaviour alone can be the foundation for scientific psychology.
Behaviorism originated in the field of psychology, but it has had a much wider influence. Its concepts and methods are used in education, and many education courses at college are based on the same assumptions about man as behaviorism. Behaviorism has infiltrated sociology, in the form of sociobiology, the belief that moral values are rooted in biology.
The "father of behaviorism" was John B. Watson (1878-1958). Watson originally trained in physhiology but turned to a stronger intgerest in comparative psychology, the study of the behaviour of nonhumans. Watson observed that while the rats he studied could not introspect or offer self-reports of their behaviour, they could still behave, and their behaviour could be objectively observed and measured.
Watson's heir apparent as champion of behaviourism was undeniably the late B. F. Skinner (1904-1990), who became best known for his studies of animal learning and what it can teach humans about better ways to live and function.