Stimulus shaping
Gradually changing the shape or form of a stimulus, step by step, from one that already evokes the correct response into the target stimulus.
In stimulus shaping, the teaching starts with a stimulus the learner already responds to correctly, and its form (topography) is changed in small steps until it becomes the target stimulus. For example, to teach reading the word "apple," a drawing of an apple might gradually be redrawn over several steps until only the printed letters remain. At each step the learner continues to respond correctly.
Stimulus shaping is closely related to stimulus fading. The difference is that stimulus fading reduces an added or exaggerated feature, such as size, color or brightness, while stimulus shaping changes the configuration of the stimulus itself. Both are errorless methods for transferring stimulus control and are used to remove stimulus prompts.
Stimulus shaping requires careful preparation of materials, so the supervisor or the program designer usually creates the series of stimuli in advance. The RBT presents the stimulus for the current step, reinforces correct responses and records data, moving between steps only according to the plan.
Stimulus shaping is different from shaping (C.10). Shaping reinforces successive approximations of a response; stimulus shaping changes the antecedent stimulus.
Example and non-example
| Example | To teach a client to recognize the numeral 1, the program starts with a picture of one candle and changes the drawing across steps until it becomes the numeral 1. The client says "one" at every step. |
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| Non-example | The numeral 1 is printed in bright red and the red slowly fades to black over sessions. Reducing the color highlight is stimulus fading. |
Don't confuse it with
| Stimulus fading | Stimulus fading reduces an added feature such as color or size; stimulus shaping changes the form of the stimulus. |
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| Shaping | Shaping changes the learner's response through successive approximations; stimulus shaping changes the antecedent stimulus. |
Test yourself
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Question 1To teach a child to read the word "sun," a plan starts with a drawing of a sun built into the printed word. Across steps, the drawing's outline is gradually changed until only the plain printed word "sun" remains. What is this procedure called?
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D: Stimulus shaping. Stimulus shaping gradually changes the form (topography) of a stimulus, here a picture that changes step by step into the printed word. Like stimulus fading, it is a way to move control from added cues to the natural stimulus.
- A: Graduated guidance is physical help adjusted during the response; this procedure changes the printed materials.
- B: Progressive time delay changes the wait before a prompt, not the shape of the materials.
- C: Backward chaining teaches the last step of a chain first; reading one word is not taught as a chain here.
Task C.7 · 40-hour curriculum section E
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Question 2A client writes letters too large for the lines on the page. The RBT reinforces letters that fit within the lines slightly better than before, using the same plain lined paper throughout. Which procedure is this?
Show answer
B: Shaping. The RBT is reinforcing responses (the written letters) that come closer to the target size. The paper does not change, so it is shaping of the response.
- A: Stimulus shaping changes the form of an antecedent stimulus, but the paper stays the same.
- C: Total task chaining teaches all steps of a sequence each time; writing letters smaller is not a chain of steps.
- D: Graduated guidance is a physical prompting procedure, and no physical prompting is described.
Task C.10 · 40-hour curriculum section E
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On the RBT exam
This term belongs to task C.7 Prompting and prompt fading in content area C, Behavior Acquisition, which is 19 of the 75 scored questions.