Shaping

The term shaping was coined by B. F. Skinner to refer to both a specific teaching technique and a general learning process. Shaping is the technique whereby a behavior totally outside the learner's current repertoire of skills is carefully brought into existence by reinforcing successive approximations to the desired performance. Shaping also refers to the learning process that takes place whenever a behavior is modified or molded over time by the consequences that differentiate its various forms.

Although not always the case, shaping is most commonly employed when, for whatever reason, the learner can neither follow verbal instructions on how to perform the desired skill nor readily imitate the behavior of another who can perform the skill. When shaping a behavior, the teacher (or therapist or trainer) starts by reinforcing whatever specific action the learner currently exhibits that is most like the new skill the teacher wants the learner to acquire. Often, the response initially selected for reinforcement bears little resemblance to the performance that is ultimately desired, even though the teacher always selects the closest approximation to that final action that the learner is now likely to perform. When repeated reinforcement has made this initial response more frequent, reinforcement of that behavior is stopped and the behavioral criterion that must be met to obtain further reinforcement is shifted to an action that is slightly closer to the ultimate performance desired. Typically, this new criterion behavior is one that, although not likely to occur at the start of training, has begun to appear during the period when responses that met the previous criterion were getting stronger, but sometimes, it is the discontinuation of reinforcement or extinction of the previously reinforced behavior that stimulates occurrence of variations that meet the new criterion. Thus, the technique takes advantage of closer approximations to the desired behavior that emerge naturally, along with other variations in behavior, during the course of reinforcing and extinguishing earlier approximations. When the newly selected criterion behavior is occurring reliably, the teacher again changes the requirement to a behavior in the direction of the final goal. Teaching proceeds in this fashion, often quite rapidly, moving smoothly across a continuum of criteria for reinforcement that approximate ever more closely the final performance desired, until that performance is attained. It is for this reason that shaping is also known as the method of successive approximations.

Through skillful shaping, novel, elaborate, and even peculiar acts never previously performed can be brought into existence. For example, shaping has been used to teach parrots to roller skate and ride bicycles, raccoons to play basketball, and chickens to peck out tunes on miniature pianos. Far less frivolously, shaping has also been used to teach speech to language-delayed children and to help stroke victims and other brain-damaged individuals recover functional use of affected arms and hands. As a learning process, shaping is inherent to any change in behavior where a skill is seamlessly altered or honed because of its direct and immediate consequences. Modern coaches of sports or art forms where precision in skilled movement is important (e.g., gymnastics, figure skating, ballet) take advantage of this fact by deliberately and strategically providing salient and immediate differential response consequences in their coaching practice.

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