Stimulus discrimination
Responding differently in the presence of different stimuli, for example making a response when the SD is present but not when another stimulus is present.
Stimulus discrimination is the outcome of discrimination training. A learner shows stimulus discrimination when their behavior changes depending on which stimulus is present: they say "cat" when shown a cat and "dog" when shown a dog, or they say "Hi" to familiar people but not to strangers in a store. The learner is responding to the differences between stimuli.
It is the opposite of stimulus generalization, in which the same response occurs in the presence of different but similar stimuli. Both are needed. A learner should call all kinds of dogs "dog" (generalization) but should not call cats "dog" (discrimination). The supervisor's plan balances the two by teaching with varied examples of the target and including non-examples.
Errors that show weak discrimination include choosing the same position every time, saying the same word to every picture, or responding to the last item named rather than the current one. An RBT who notices patterns like these in the data should report them, because they suggest the response is not yet under the intended stimulus control.
Stimulus discrimination is measured with data on correct and incorrect responses across trials with different stimuli.
Example and non-example
| Example | A child who has learned to tell coins apart picks out the quarter when asked and the dime when asked, across many mixed trials. |
|---|---|
| Non-example | A child who calls every four-legged animal "dog" is showing stimulus generalization that is too broad, not discrimination. |
Don't confuse it with
| Stimulus generalization | Generalization is responding the same way to similar stimuli; discrimination is responding differently to different stimuli. |
|---|---|
| Discrimination training | Discrimination training is the procedure; stimulus discrimination is the resulting behavior. |
Test yourself
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Question 1At an adult day program, an RBT runs a coin-identification program: three coins are on the table and the instruction is "Point to the quarter." The client points to the quarter. What should the RBT do before the next trial?
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D: Change the positions of the coins as the plan directs. Rotating the positions of items in the array between trials makes sure the client responds to the target itself and not to where it sits on the table.
- A: Leaving coins in place lets the client respond by location instead of by coin.
- B: Removing the other coins takes away the discrimination the program is teaching.
- C: Changing the reinforcement requirement is a plan change for the supervisor to make.
Task C.3 · 40-hour curriculum section E
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Question 2Which statement best describes the difference between stimulus generalization and stimulus discrimination?
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B: Generalization is responding the same way to similar stimuli; discrimination is responding differently to different stimuli. In stimulus generalization, a response learned with one stimulus also occurs with similar stimuli. In stimulus discrimination, the response occurs in the presence of some stimuli and not others. Teaching usually needs both: enough generalization to new examples and enough discrimination to avoid non-examples.
- A: Both are defined by how responding relates to stimuli, and both can occur in any setting.
- C: Discrimination is built through differential reinforcement (reinforcement in the presence of the SD, none in the presence of the S-delta), not punishment.
- D: A change in response form describes response generalization; stimulus discrimination is about which stimuli occasion the response.
Task C.6 · 40-hour curriculum section E
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Question 3A client has a cup, a shoe and a ball on the table. On some trials the RBT says "Touch cup" and on others "Touch ball," so which item is correct depends on what the RBT says. What kind of discrimination is this?
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A: A conditional discrimination. In a conditional discrimination, which stimulus is correct depends on another stimulus, here the spoken instruction. Receptive identification with an array of items is a common conditional discrimination.
- B: In a simple discrimination the same stimulus is always correct; here the correct item changes with the instruction.
- C: Generalization is responding in the same way to similar stimuli, not choosing an item based on an instruction.
- D: A behavior chain is a sequence of linked responses; here each trial calls for one response.
Task C.6 · 40-hour curriculum section E
Answer every question to see your score.
On the RBT exam
This term belongs to task C.6 Discrimination training in content area C, Behavior Acquisition, which is 19 of the 75 scored questions.