Stimulus Control

Description

Stimulus control is a learning phenomenon that is evident in all facets of everyday life. To illustrate, when motorists encounter a red traffic light, they come to a stop. In this example, the red light is the stimulus that controls the behavior of depressing the brake pedal of the vehicle. As another example, when people sit down at a personal computer and detect an icon indicating an e-mail message, they click on it. Here, the icon is the stimulus that controls the behavior of opening the e-mail inbox. When a fire alarm sounds inside a building, people exit rapidly. The alarm is the stimulus that controls the behavior of walking out of the building.

Stimulus control occurs, or is “acquired,” when objects, people, and activities are paired with behavior-elicited consequences. Thus, if a restaurant diner experiences severe nausea, stomach pain, and related discomfort after eating oysters, it is possible that the diner will never order or consume this type of seafood again. The negative physical consequences that were encountered in close proximity to consuming the oysters cause them to be a stimulus that is avoided, thereby controlling eating behavior. Acquisition of stimulus control also results from the contiguous pairing of positive consequences. Students, as an example, are likely to approach, speak to, smile at, and seek the attention of classroom teachers who are nurturing, supportive, and consistently positive during social interactions. The mere presence of such teachers typically will produce these behaviors.

As gleaned from the preceding discussion, a stimulus can be animate or inanimate. In many situations, it is an individual's direct contact with positive or negative consequences in the presence of a stimulus that establishes control. This effect would be evident in the case of a child who had extreme fear of physicians and hospitals as the result of undergoing a painful medical procedure. However, stimulus control also is possible [Page 1549]even if an individual has not actually experienced consequences. Sometimes, it can be established merely by observing someone's behavior, that is, by witnessing a model. Verbal instructions may also be a sufficient influence on learning. A child, for example, might learn to avoid physical contact with a hot stove not because that child has actually done so but in response to a parent's admonition, “Don't ever touch the stove; it's hot and you can burn yourself!”

Although stimulus control frequently is acquired under narrowly defined conditions and through pairing with unique consequences, the effects commonly “spread” or generalize to other situations and circumstances. Indeed, human behavior can be qualified as “adaptive” because stimulus generalization is evident. With regard to the previous red light example, we learn to brake in the presence of all traffic lights that are red. Here, our behavior has come under the control of a single (and relatively uniform) stimulus found in multiple contexts. Another type of generalization is when control over behavior is exerted by variations or different features of an initially conditioned stimulus. For example, telephones exist in many shapes, sizes, and styles, but despite these differences, the behavior of making a telephone call is invariant.

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