In psychology, the doctrine that all human actions could, if full knowledge were available, be analyzed into stimulus and response. Stimulus is something that stimulates, meaning thereby, that excites, rouses, or quickens thought or feeling. Behaviorism, a theoretical point of view that holds that the subject matter of psychology is behavior without reference to consciousness or mentalistic constructs, as a formal school of psychology had its inception in the work of John B. Watson. In a paper that appeared in the Psychological Review in 1913 Watson gave his definition of psychology as follows: “… a purely objective experimental branch of natural science. Its goal is the prediction and control of behavior….The time seems to have come when psychology must discard all reference to consciousness; when it need no longer delude itself into thinking that it is making mental states the object of observation.” The behavioristic perspective is organized around one central theme: the role of learning in human behavior. The simple form of learning, known as conditioning is the basis for behaviorism. The discovery of conditioned reflex by the Russian physiologist Ivan Pavlov excited Watson, who was searching for objective ways to study human behavior. Pavlov demonstrated that a dog would learn to salivate to a nonfood stimulus, such as a bell, after the stimulus had been regularly accompanied by the presentation of food. Watson reasoned that if psychology were to become a true science, it must abandon the subjectivity of inner sensations and other “mental” events and limit itself to what could be objectively observed. Basics of the behavioristic perspective. The behaviorists have focused on the effects of environmental conditions (stimuli) on the acquisition, modification, and possible elimination of various response patterns-both adaptive and maladaptive. 1.Classical (respondent) and operant conditioning. A specific stimulus may elicit a specific response. Through conditioning, the same response may come to be elicited by a wide range of other stimuli. This form of conditioning is called classical conditioning-its advantage is that the response is elicited by the stimulus. In operant conditioning, the individual learns how to achieve a desired goal. The goal may be to obtain something that is rewarding or to avoid something that is unpleasant. What an individual learns will be accurate or useful depend on experiences. 2.Reinforcement. It is essential to both types of conditioning. The strengthening of a new response by its repeated association with some unconditioned stimulus is called a reinforcer that may be either positive (pleasant) or negative (aversive). Initially a high rate of reinforcement is necessary to establish a response but lesser rates are usually enough to maintain it. However, when reinforcement is consistently withheld, the cobditioned response-whether classical or operant- eventually extinguishes. It may also occur in avoidance conditioning. 3.Generalization and discrimination. If a response is conditioned to one stimulus or set of stimulus conditions, it tends to become associated with other stimuli in proportion to the degree of similarity between the original and the new stimuli; this process is called generalization. When the individual learns to distinguish between similar stimuli and to respond differently to them, it is discrimination. 4. Modeling, shaping, and learned drives. The basic concepts, in addition, of the behaviorist approach are modeling, shaping, and primary and secondary drives. All human actions are not the outcomes of stimulus or stimulus condition as instinct is a natural tendency to behave in a certain way without reasoning or training. It is innate or ibherited tendencies that are the motive power behind all thought and action. Besides, stimulus excites but instinctive or distinctive response motivates.