When a behavior is reinforced only in the presence of a particular stimulus in operant conditioning, which concept is being applied?

The correct answer is the concept of a discriminative stimulus. In operant conditioning, a discriminative stimulus signals the availability of reinforcement in the presence of that specific stimulus. When a behavior is reinforced only when a particular stimulus is present, it helps the individual learn to associate that stimulus with the opportunity for reinforcement. This allows them to distinguish between situations where the behavior will or will not be rewarded.

In contrast, stimulus generalization refers to the tendency for a behavior to occur in the presence of stimuli similar to the original stimulus, without the specific reinforcement. Operant conditioning is a broader term that encompasses various learning processes involving reinforcement and punishment, but it does not specifically capture the idea of a stimulus indicating reinforcement. Stimulus discrimination, on the other hand, refers to the ability to differentiate between similar stimuli but doesn't emphasize the signal that a behavior will be reinforced, which is the focus of the discriminative stimulus.