StimulusStimulus is defined as any change in the environment or... Discrimination refers to the ability to differentiate between different stimuli and respond appropriately to each. It occurs when a behaviorBehavior refers to any activity or action that living o... is reinforced in the presence of one stimulus (discriminative stimulus, or SD) but not in the presence of other stimuli (S-deltas), leading the learner to respond only when the correct stimulus is present.
Example
A child learns to say “dog” when shown a picture of a dog (SD), but does not say “dog” when shown a picture of a cat (S-delta). The child has developed stimulus discrimination because they can distinguish between the two different stimuli and respond only to the appropriate one (the picture of the dog).