What is Stimulus Control?
Stimulus control refers to behavior that occurs more often in the presence of a stimulus than in its absence. Stimulus control occurs when the rate, latency, duration, or magnitude of a response is altered in the presence of an antecedent stimuli. Drivers stop in the presence of stop signs, children act differently in the presence of certain adults, and we all act differently around someone we have a crush on. Stimulus control is essential when meeting the demands of different environments. Stimulus control is related to stimulus discrimination, stimulus generalization, faulty stimulus control, and even respondent soliciting. Through stimulus control, we talk quietly in libraries, speak loudly at concerts, and communicate solemnly at funerals. Our behaviors are under stimulus control day-in and day-out.
Manipulating the presence of antecedent stimuli to coincide with the availability of reinforcement can lead to stimulus discrimination. When we teach children colors, we will say “green” and only provide reinforcement when the child selects green. Eventually, their behavior will come under the control of the word “green,” or the color green. Green is the discriminative stimulus signaling reinforcement, while other colors are the stimulus delta signaling reinforcement is not available. The SD will lead to higher responding due to the availability of reinforcement, while the S-Delta will lead to less responding.
Basic stimulus discrimination involves multiple schedules with different antecedent conditions representing each schedule. Responses in the presence of the SD are reinforced and responses in the presence of the Sdelta are not reinforced.
Stimulus generalization occurs when other stimuli, aside from the SD, acquire control over behavior. Stimuli with similar properties with the SD are most likely to generalize. For instance, animals with four legs are more likely to evoke “dog” compared to animals with two legs or wings. When stimulus generalization occurs, stimulus control is demonstrated for one behavior across multiple stimuli.
Faulty Stimulus Control and Conditional Stimulus Control
Faulty stimulus control occurs when a behavior comes under the control of an irrelevant antecedent stimulus. Some examples include:
- Learners can use pictures or diagrams instead of text to complete an exercise
- Highlight or physical layout gives away answers
- Can learners answer questions without reading the passage?
- Does every problem require the same process for the solution?
With a simple stimulus discrimination, only one antecedent stimulus controls the response. With conditional stimulus control, a response in the presence of a particular stimulus depends on the presence or absence of other stimuli. For example, asking a child to pick their red shirt. The color is the conditional stimulus while the shirt is the discriminative stimulus.
Factors That Affect the Development of Stimulus Control
Academic or social skills require the learner to orient themselves appropriate to the SD in the instructional setting. These skills can include: looking at the instructor, looking at the materials, looking at a model, listening to oral instruction, and sitting for an appropriate amount of time during an appropriate moment.
Salience is in reference to the prominence of a stimulus in the learner’s environment. Stimuli can acquire salience depending on the learner’s capabilities, learning history, and the context of the environment. Another way to determine salience is to observe how a learner reacts to a change in the stimulus.
Overselective Stimulus Control
The range of stimulus control is too limited. When a learner focuses on a specific portion of a stimulus, instead of seeing the stimulus as a whole, overselective stimulus control may be occurring.
Stimulus Blocking and Overshadowing
Blocking and overshadowing can decrease stimulus salience. Blocking, or masking, occurs when a competing stimulus blocks the evocative function of a controlling stimulus. Overshadowing occurs when a more salient stimulus blocks the acquisition of stimulus control.
Stimulus Control Transfer Procedures
Transferring stimulus control typically occurs when you want to shift stimulus control from a prompt to the proper SD. Prompts occur in the form of least-to-most, most-to-least, and graduated guidance. When using prompts to transfer stimulus control, you want to begin fading your prompts as quickly as possible.
- When a child’s learning history is unknown, you should typically use a most-to-least prompting procedure
- If a child makes a lot of errors, or if errors lead to maladaptive behavior, you should use most-to-least or errorless learning
- Least-to-most can. be used if learners demonstrate the ability to quickly acquire new skills
Both response prompts and stimulus prompts should be faded out in order to properly transfer stimulus control. Stimulus fading involves changing a component of the stimulus, and then reducing that change systematically.