Molding or method of successive approximations: uses and characteristics

This behavior modification technique is one of the most widely used in the educational field.

Shaping is a technique used to promote learning, especially in children with special needs. It was first described by the 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 shaping is, also called the "method of successive approximations", because it basically consists of because it basically consists of selectively reinforcing a behavior so that it ends up adopting a specific topography and function. We will also discuss some of the operant techniques that are often used in conjunction with shaping.

What is shaping?

Shaping is a learning paradigm that is framed within operant conditioning.. In the context of applied behavior analysis, which was developed by Burrhus Frederick Skinner, the shaping of behaviors is usually 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 learning subject's behavioral repertoire. By selectively reinforcing behaviors that are increasingly similar to the one to be established, they are strengthened while those that are less precise tend to die out due to the lack of contingency with reinforcement.

Thus, the fundamental mechanism of these behavioral techniques is reinforcement, particularly differential reinforcement.particularly of the differential type. Since the middle of the 20th century, we have known that it is more effective to focus instruction processes on the reinforcement of desirable behaviors than on the punishment of incorrect ones, both for ethical and purely practical reasons.

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 subject's repertoire with the aim of forming complex behavioral chains, such as starting a vehicle or playing a musical instrument.

A special variant of this operant paradigm is self-learning, in which a conditioned stimulus is paired with an unconditioned stimulus without the learning subject's behavior influencing the process. Therefore, self-molding is not included within operant or Skinnerian conditioning. but of the classical or Pavlovian method.

The method of successive approximations

In order to apply shaping and the method of successive approximations, it is first necessary to determine the final behavior that the subject will have to learn to perform. Then his repertoire of responses is evaluated, usually through behavioral tests, to identify one that can be a good starting point for learning.

Specifically, the objective is to to select a behavior that the subject can carry out without problem and that is as similar as possible to the target response, both topographically (e.g. type of muscle movements involved) and functionally; this term refers to the goal or function that a given behavior fulfills.

The next step is to determine the steps that will lead from the initial behavior to the final behavior, i.e., the steps that will lead from the initial behavior to the final behavior, successive approximations to the target behavior. It is advisable to test the sequence before applying it and, if necessary, it should also be reviewed during the shaping process to enhance its effectiveness.

Shaping has been successfully used in a large number of different applications. Among the most relevant are special education (such as autism and functional diversity in general), motor rehabilitation after injuries and sexual dysfunctions; Masters and Johnson's method for treating Erectile Dysfunction is a good example.

Associated operant techniques

Molding 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 we know today originally emerged. This was based on associating certain actions to stimuli produced by the effects that this behavior has when applied to the environment.

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

The ultimate goal is for the target behavior to become controlled by natural reinforcers, such as social reinforcers (like smiles and even attentive glances), rather than by discriminative stimuli, which are a good way to develop behaviors but not to maintain them. This process can be referred to as "transfer of stimulus control".

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