What is the primary function of a discriminative stimulus in operant conditioning?

• A. To signal that reinforcement is available for a response
• B. To signal punishment is available
• C. To extinguish a response
• D. To generalize responses

Answer: (A)

The discriminative stimulus is a cue that signals reinforcement is available for a given response. It sets the occasion for the behavior to occur by indicating that in this situation, performing the response is likely to be rewarded. For example, in a Skinner box, a light turning on may signal that lever presses will be reinforced with food; when the light is off, lever pressing yields no reinforcement, so the animal is less likely to respond. The stimulus itself isn’t the reinforcer; it controls behavior by signaling when reinforcement can happen. This is different from a cue that signals punishment, which would indicate an aversive outcome following the response. It’s also not about extinguishing the response or generalizing responses, which are separate processes.