In the ABCs of learning, what does SD stand for?

• A. Discriminative stimulus
• B. Stimulus for desire
• C. Subsequent determinant
• D. Standard difference

Answer: (A)

The discriminative stimulus is the cue in the antecedent that signals reinforcement is available for a specific behavior. In the ABCs of learning—Antecedent, Behavior, Consequence—this cue sets the occasion for the response because the animal has learned that performing the behavior when this cue is present will be followed by a reward. For example, when a trainer presents treats and uses a clear cue like “sit,” that setup becomes the discriminative stimulus for the dog to sit in order to receive reinforcement. Outside of that cue, reinforcement is unlikely, so the behavior is less likely to occur. This is why the standard term Discriminative Stimulus best fits the concept.