Behaviorism (or Behaviourism) is an approach to psychology based on the proposition that behavior is interesting and worthy of scientific research. Within that broad approach, there are different emphases. Some \behaviorists argue simply that the observation of behavior is the best or most convenient way of investigating psychological and mental processes. Others believe that it is in fact the only way of investigating such process, while still others argue that behavior itself is the only appropriate subject of psychology, and that common psychological terms (belief, goals, etc.) have no referents and/or only refer to behavior. Those taking this point of view sometimes refer to their field of study as behavior analysis or behavioral science rather than psychology.
Early in the 20th century, John B. Watson argued in his article Psychology from the standpoint of a behaviorist for the value of a psychology which concerned itself with behavior in and of itself, not as a method of studying consciousness. This was a substantial break from the structuralist psychology of the time, which used the method of introspection and considered the study of behavior valueless. Watson, in contrast, studied the adjustment of organisms to their environments, more specifically the particular stimuli leading organisms to make their responses. Much of Watson's work was comparative, i.e., he manipulated and observed changes in the behavior of animals. Watson's work was much influenced by the work of Russian physiologist Ivan Pavlov, who had stumbled upon the phenomenon of classical conditioning (which were essentially learned reflexes) in his study of the digestive system of the dog, and subsequently investigated the phenomena in detail. Watson's ideas heavily emphasized physiology and the role of stimuli in producing conditioned responses. For this reason, Watson has often been described as an S-R (stimulus-response) psychologist.
Watson's behaviorist manifesto persuaded most academic researchers in experimental psychology of the importance of studying behavior. In the field of comparative psychology in particular, it was consistent with the warning note that had been struck by Lloyd Morgan's canon, against some of the more anthropomorphic work such as that of George Romanes, in which mental states had been freely attributed to animals. It was eagerly seized on by researchers such as Edward L. Thorndike (who had been studying cats' abilities to escape from puzzle boxes). However, most psychologists took up a position that is now called methodological behaviorism: they acknowledged that behavior was either the only or the easiest method of observation in psychology, but held that it could be used to draw conclusions about mental states. Among well-known twentieth-century behaviorists taking this kind of position were Clark L. Hull, who described his position as neo-behaviorism, and Edward C. Tolman, who developed much of what would later become the cognitivist program. Tolman argued that rats constructed cognitive maps of the mazes they learned even in the absence of reward, and that the connection between stimulus and response (S->R) was mediated by a third term - the organism (S->O->R). His approach has been called, among other things, purposive behaviorism
Methodological behaviorism remains the position of most experimental psychologists to-day, including the vast majority of those who work in cognitive psychology - so long as behavior is defined as including speech, at least non-introspective speech. With the rise of interest in animal cognition since the 1980s, and the more unorthodox views of Donald Griffin among others, mentalistic language including discussion of conscsiousness is increasingly used even in discussion of animal psychology, in both comparative psychology and ethology; however this is in no way inconsistent with the position of methodological behaviorism.
This is one of the clear distinctions between Skinner's notions and the S-R notions of many of his predecessors. Another crucial contribution was his clarification of the key concept of reinforcement, which had been introduced by Thorndike and used extensively by Hull, but seemed to be mired in issues of definitional circularity. Whereas Thorndike had tried to define reinforcement mentalistically, as a "satisfying state of affairs", and Hull had tried to define it physiologically, in terms of the reduction of a drive, Skinner defined it empirically: if an event was experimentally observed to increase the rate of response, it was then called a reinforcer for that particular animal at that time. Food, water, brain stimulation, sex, social contact, and reinforcing drugs are all reinforcers that have been used in operant research with animals. The issue of whether these stimuli were satisfying to the animal (Thorndike's definition) was thereby bypassed, and the issue of whether they involved the reduction of a drive was left open for empirical physiological investigation (and it was quickly realised that many do not).
Skinner's empirical work expanded on earlier research on trial-and-error learning by researchers such as Thorndike and Guthrie with both conceptual reformulations - Thorndike's notion of a stimulus-response 'association' or 'connection' was abandoned - and methodological ones - the use of the 'free operant', so called because the animal was now permitted to respond at its own rate rather than in a series of trials determined by the experimenter procedures. With this method, Skinner carried out substantial experimental work on the effects of different schedules and rates of reinforcement on the rates of operant responses made by rats and pigeons. He achieved remarkable success in training animals to perform unexpected responses, and to emit large numbers of responses, and to demonstrate many empirical regularities at the purely behavioural level. This gave credibility to his conceptual analysis.
In any case, what was important for a behaviorist analysis of human behavior was not language acquisition so much as the interaction between language and overt behavior. In an essay republished in his 1969 book Contingencies of reinforcement, Skinner took the view that humans could construct linguistic stimuli that would then acquire control over their behavior in the same way that external stimuli could. The possibility of such instructional control over behavior meant that contingencies of reinforcement would not always produce the same effects on human behavior as they reliably do in other animals. The focus of a radical behaviorist analysis of human behavior therefore shifted to an attempt to understand the interaction between instructional control and contingency control, and also to understand the behavioral processes that determine what instructions are constructed and what control they acquire over behavior. Important figures in this effort have been A. Charles Catania and C. Fergus Lowe.
Although behaviorism is primarily thought of as a psychological movement, there have also been points of view within philosophy that have called themselves, or have been called by others, behaviorist. The best known is the logical behaviorism of Gilbert Ryle. While exponents of it do not in general align themselves with Skinner — who is not well-regarded in the intellectual community — logical behaviorism does have many points in common with Skinner's radical behaviorism, not least a resolute opposition to methodological behaviorism, and a policy of avoiding the use of mental events in scientific explanations of behavior. Logical behaviorism, true to the tradition of behaviorism, leaves no room for qualia. According to logical behaviorism qualities are not in objects; they are just dispositions to act in specific ways and can be seen as IF->THEN statements.
It is also often argued - especially by theoreticians within the experimental analysis of behavior community - that the thought of Ludwig Wittgenstein is essentially behaviorist. Wittgenstein did not call himself a behaviorist, and his style of writing is sufficiently elliptical and allusive to admit of a range of interpretations.