Logan: Principles of Learning PRINCIPLE: STIMULUS-RESPONSE CONTIGUITY There is an increased likelihood that the organism will repeat the last response made on the previous occasion of a stimulus event. This principle is, to S-R theory, what sensory conditioning is to S-S theory. Whereas the latter asserts that stimuli become associated simply as a result of occurring contiguously in space and time, the former asserts that a response becomes associated with a stimulus simply as a result of practice. Just as classical conditioning might be interpreted as a particular case of sensory conditioning, so equally might it be interpreted as a particular case of S-R contiguity. That is to say, the paradigm of classical conditioning could be viewed as one way in which to insure that the response of interest does indeed occur in the context of the antecedent stimulus. The essence of the principle is that the temporal contiguity of a response and a stimulus is sufficient to produce learning. This is not an easy principle to demonstrate experimentally, but an illustrative study would involve placing a rat in a running wheel that is wired so that any time that the rat runs, a tone sounds. In such a study, there is no US that reflexively elicits running behavior; we have only arranged for a tone to sound whenever the rat is "spontaneously" running. Then, after some period of exposure to these circumstances, the tone is sounded when the rat is not running. There is evidence that the rat will start to run after the tone sounds. The somewhat tenuous nature of this type of support for the Principle of S-R Contiguity is that the tone is not sounded until after the rat has started to run; a more ideal but technically impossible procedure would be to have the tone come on just before the rat spontaneously began to run. It is important to recognize that for all S-R theorists, S-R contiguity is a necessary condition for learning. At issue is whether contiguity is sufficient. Those who would deny the principle of S-R contiguity contend that some other conditions must also be satisfied for learning to occur. Specifically, the most common alternative theory contends that, in addition to S-R contiguity, reinforcement is also necessary for learning. The popularity of S-R reinforcement theory dates back to the 1920's with Thorndike's statement of the Law of Effect, that organisms tend to learn responses that are followed by "satisfying" consequences. Subsequently, however, almost all learning theorists have accepted the sufficiency of the contiguity principle, be it the S-R or the S-S version. You learn what you practice, regardless of whether or not you want to learn it and regardless of whether or not you are reinforced for doing so. As might by now be anticipated there is an alternative explanation of the S-R contiguity principle. The reason for repeating this controversial thread is not because one or the other approach is right or better than the other, but because viewing the principle from contrasting perspectives may help to increase one's understanding of the principle itself. In this case it is necessary to introduce the important concept or response-produced feedback. It is presumed that whenever a response occurs, it is accompanied by some form of response occurs, it is accompanied by some form of proprioceptive or kinesthetic stimuli from the glands, muscles, and joints involved in that response. The important function of this feedback is to inform the organism of the behavior that is taking place. We shall have occasion to refer to such response-produced feedback throughout this book. As regards the S-R contiguity principle, it is only necessary to recognize that the exteroceptive stimulus occurs contiguously with the feedback stimulus. Specifically, at the same time that the rat feels himself running, he hears the tone. Hence, what at first glance to be S-R think about running. This does not necessarily mean that the rat will actually start to run, but there is a strong tendency to do whatever we are thinking about doing. It is known, for example, that when humans are instructed to think about moving their fingers, just the thought will lead to small muscular contractions in the fingers. A special case of the S-R contiguity principle occurs in response chains. We refer to a BEHAVIOR CHAIN when the feedback from each response sets the occasion for the next response. Almost all responses can be viewed as a chain of more molecular units; for example, a rat's bar-press entails approaching the bar, raising up on the hind legs, placing the front paws on the bar, pressing down, and then releasing. The entire sequence becomes integrated as a result of S-R contiguity, where the S is response-produced feedback of the preceding response. In similar fashion, a great many human responses, from pronouncing a word to executing a dance step, are behavior chains that run off as each component action, in turn, leads on to the next action. In spite of its apparent simplicity the S-R contiguity principle has wide ranging practical implications. It says that mere repetition will make any response habitual. This applies not only to motor behavior but also to mental activities. For example, alertness, worrying, daydreaming, and preoccupation with sexual, aggressive, or belittling thoughts can become habitually associated with various contexts. Every time we engage in one or another form of behavior, we increase the likelihood of continuing to engage in it. As with all basic Principles of Learning the S-R contiguity principle is indifferent as to whether the behavior is desirable or undesirable, adaptive or maladaptive, stupid or intelligent. Every lie is toward the making of a liar; every crime is toward the making of a criminal; every cigarette is toward the making of a smoker. But fortunately in such situations, the principle is reversible; not engaging in previously habitual behavior can make not engaging in it also habitual. TERMS: Contiguity (s-r), sensory conditioning, response-produced feedback, Law of Effect, response, stimulus, exteroceptive stimulus, interoceptive stimulus, reinforcement theory.