Why did behaviourism occur, what forms did it take, and why and how was it replaced by cognitive psychology as the dominant paradigm in psychology?

This chapter presents a number of interrelated concepts: Why introspection was rejected as a method by psychologists, the assumptions and different forms of behaviourism, why cognitive psychology replaced behaviourism as the dominant paradigm, and how cognitive psychology differs from or is related to behaviourism. Paradigms in psychology are based on assumptions, untested metatheoretical assumptions. Behaviourism was one of those paradigms. It is based on a set of assumptions, the primary one being that human behaviour has the same causes as that of rat behaviour. However, the assumptions of behaviourism changed slightly as time went on, so although it is perfectly possible to write about ‘behaviourism’ as a single ‘thing,’ the chapter tells the story of a series of ideas that developed between the beginning of the 20th century till about 1950. It tells the story from the time before behaviourism started until after it was no longer the dominant paradigm.