BA400 Unit 8 Stimulus Control and Generalization Example

Dolores Could Pay at One Grocery Store: A BA400 Unit 8 Stimulus Control and Generalization Paper

[Student Name]

Purdue University Global

BA400: Foundations of Behavior Analysis

Unit 8 Stimulus Control and Generalization Paper

[Instructor Name]

[Date]

The writer, the group home, the resident and every figure are composite and illustrative; the articles and book cited are real.

A Skill That Stayed Home

Shopping trips are a regular part of my job, because residents are working toward running their own errands. Dolores, 58, has a mild intellectual disability and wants to shop more independently. Over two months last winter, staff taught her to pay at the checkout of the grocery store near our house. The steps were simple: put items on the belt, wait for the total, hand the cashier a bill larger than the total, wait for change and say thank you. By March, she completed every step without help on eight consecutive trips, and staff marked the goal as met.

In April, I took Dolores to a pharmacy to buy lotion. At the register, the cashier scanned the item and looked at her. Dolores stood still, holding her wallet, until I prompted her. The same thing happened at a dollar store the next week, and Dolores told me afterward that the stores "didn't work right," which turned out to be a fair description of what she had learned.

Stimulus Control

A behavior is under stimulus control when it occurs more often in the presence of a particular stimulus than in its absence. Cooper et al. (2020) explain that stimulus control develops through differential reinforcement: when a behavior is reinforced in the presence of a stimulus and not in its absence, that stimulus comes to occasion the behavior.

Reviewing the training sheets, the team found the problem. At the grocery store, Dolores had usually been served by the same cashier, who always said, "That'll be" followed by the total, and the total always appeared on a large green screen at eye level. Dolores had been prompted to pay when the cashier spoke and reinforced with praise when she did. Over time, the phrase "That'll be" had become the discriminative stimulus for handing over money. At the pharmacy, the cashier said nothing and the total appeared on a small screen she could not easily see.

Dolores had not learned to pay at a register; she had learned to pay when one cashier said "That'll be."

Generalization

Generalization refers to a behavior occurring under conditions different from those of training, such as new settings, people or materials, and to its lasting over time. Baer et al. (1968) named generality as a defining dimension of applied behavior analysis, insisting that useful behavior change must appear beyond the training situation.

Stokes and Baer (1977) reviewed applied research and argued that generalization had too often been expected to happen on its own, an approach they called train and hope. They described strategies for programming generalization instead, including training sufficient exemplars, training loosely by varying irrelevant features of the teaching situation, programming common stimuli that will be present in both training and new settings, introducing the behavior to natural contingencies that will maintain it, and mediating generalization with a self-provided cue.

Dolores's training had been train and hope. One store, one cashier and one consistent phrase produced a skill controlled by features of that setting that were irrelevant to paying.

Redesigning the Training

The behavior specialist redesigned Dolores's program using four of Stokes and Baer's strategies.

Sufficient exemplars: Dolores practiced at three stores, the grocery store, the pharmacy and a dollar store, rotating each week, with different cashiers.

Train loosely: staff varied what happened at the register. Sometimes they asked the cashier, beforehand, to say the total, sometimes to stay silent, sometimes to point at the screen. Dolores practiced with different amounts and different screen locations.

Program common stimuli: Dolores received a small card in her wallet showing the steps in pictures, with the first picture showing a cashier finishing scanning. The card traveled with her to every store.

Natural contingencies: staff faded their praise and let the natural consequences, receiving her items and change and a cashier's thank you, maintain the behavior.

Results

Within six weeks, Dolores paid without prompts at all three training stores. Then came the test: a farmers market, where vendors take cash at folding tables with no screen and no belt. On her first visit, she watched a vendor bag her tomatoes, took out her card, looked at it, took out a bill and handed it over. She paid independently at four of five stalls that day; at the fifth, a vendor who took cards only, she asked a staff member what to do, which was exactly the right response.

Avoiding Overgeneralization

Broadening stimulus control carries its own risk. If Dolores learned to hand money to anyone who looked at her after handling her items, she might pay at the wrong moment, such as when a pharmacist hands her a prescription bag to check, or hand money to a stranger. The redesigned training addressed this by including situations where paying was not appropriate. At the pharmacy, staff practiced picking up a prescription that had already been paid for by insurance, and Dolores learned to look at the screen or ask, "Do I owe anything?" before opening her wallet. The goal was not that she pays whenever someone looks at her, but that paying comes under control of the features that actually matter: items finished, a total shown or spoken, and a person waiting to be paid.

What the Case Teaches

The case shows that a skill can appear mastered while being controlled by the wrong stimuli. The data from the original training looked excellent, eight independent trips in a row, because they were collected only in the training setting. Generalization probes, brief tests in new settings without teaching, would have exposed the problem sooner. Our team now builds probes into every community skill program, scheduling a test in an untrained setting every two weeks and treating a failed probe as information about the training rather than about the resident.

Conclusion

Dolores's payment skill was under narrow stimulus control, cued by one cashier's phrase rather than by the end of scanning, because her training followed train and hope. Stokes and Baer's strategies, multiple exemplars, loose training, a common stimulus she carries and natural contingencies, broadened that control until she could pay at a farmers market she had never visited. The lesson for staff is to plan for generalization from the first day of teaching.

References

Baer, D. M., Wolf, M. M., & Risley, T. R. (1968). Some current dimensions of applied behavior analysis. Journal of Applied Behavior Analysis, 1(1), 91-97. https://doi.org/10.1901/jaba.1968.1-91

Cooper, J. O., Heron, T. E., & Heward, W. L. (2020). Applied behavior analysis (3rd ed.). Pearson.

Stokes, T. F., & Baer, D. M. (1977). An implicit technology of generalization. Journal of Applied Behavior Analysis, 10(2), 349-367. https://doi.org/10.1901/jaba.1977.10-349