Shaping or method of successive approximations

Shaping is a technique used to promote learning, especially in minors with special needs. It was first described by psychologist B. F. Skinner, father of operant conditioning, and was a fundamental milestone in the development of this behaviorist paradigm.

In this article we will explain what is shaping, also called "method of successive approximations" because it basically consists of reinforcing a behavior selectively so that it ends up adopting a specific topography and function. We will also talk about some of the operant techniques that are often used in conjunction with shaping.

• Related article: "5 behavior modification techniques"

What is molding?

Molding is a learning paradigm that is framed in operant conditioning. In the context of applied behavior analysis, which was developed by Burrhus Frederick Skinner, the shaping of behaviors is normally carried out through the method of differential reinforcement by successive approximations.

These procedures are based on the progressive modification of an existing response in the behavioral repertoire of the learner. By selectively reinforcing behaviors that are increasingly similar to the one that is intended to be established, these are strengthen while those that are less precise tend to become extinct due to lack of contingency with reinforcement.

A) Yes, the fundamental mechanism of these behavioral techniques is reinforcement, in particular the differential type. Since the middle of the 20th century, we have known that it is more effective to focus instructional processes on the reinforcement of desirable behaviors than in the punishment of other incorrect ones, both for ethical reasons and for other purely practices.

Shaping is one of the operant techniques used to develop behaviors. In this sense it is similar to chaining, in which learning consists of combining simple behaviors present in the repertoire of the subject with the aim of forming complex behavioral chains, such as starting a vehicle or playing an instrument musical.

A special variant of this operant paradigm is self-shaping, in which a stimulus is paired conditioned as another unconditioned without the behavior of the learning subject influencing the process. Therefore, self-shaping is not included in skinnerian or operant conditioning but of the classic or Pavlovian.

The method of successive approximations

To apply the modeling and the method of successive approximations, it is first necessary to determine what is the final behavior that the subject must learn to perform. Their repertoire of responses is then assessed, usually through behavioral tests, to identify one that may be a good starting point for learning.

Specifically, the goal is select a behavior that the subject can carry out without problem and that it is as close as possible to the objective response, both in its topographic aspect (p. and. type of muscle movements involved) and functional; This term refers to the goal or function that a certain behavior fulfills.

The next step is to determine the steps that will lead from the initial behavior to the final one, that is, successive approximations to the target behavior. It is advisable to rehearse the sequence before applying it and, if necessary, it is also advisable to review it during the molding process in order to enhance its effectiveness.

Molding has been used successfully in a large number of different applications. Among the most relevant we find special education (such as cases of autism and functional diversity in general), motor rehabilitation after injuries and sexual dysfunctions; The Masters and Johnson method of treating erectile dysfunction is a good example.

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Associated operant techniques

Shaping is generally not applied in isolation, but in a broader intervention context: that of the operant conditioning paradigm, and in particular in applied behavior analysis, which was developed by Skinner and in which many of the operant techniques that we know in the present. This was based on associating certain actions to the stimuli produced by the effects that this behavior has when applied to the environment.

To enhance the effectiveness of the successive approximation method, this often combined with other operant procedures. In this sense, it is worth highlighting the application of discriminative stimuli that inform the subject that if he emits the correct behavior he will obtain reinforcement and the progressive fading of these.

The ultimate goal is for the target behavior to be controlled by natural reinforcements, such as social ones (such as smiles and even attentive glances), and not because of discriminative stimuli, which are a good way to develop behaviors but not to keep them. This process can be called "transfer of stimulus control."

Other operant techniques that are frequently associated with shaping are modeling, which consists of learning through observation of the behavior of others, verbal instructions and physical guidance, that would occur when a psychologist moves the hands of the child she is helping to educate to indicate how she should use a zipper.