Which schedule of reinforcement involves reinforcement following each occurrence of the target behavior that is separated from the previous response by a minimum interresponse time, or is contingent on the number of responses within a period not exceeding a predetermined criterion?

• A. DRL
• B. DRH
• C. DRD
• D. FR

Answer: (A)

Differential Reinforcement of Low Rates reinforces the target behavior only when it occurs at a slower pace than a specified criterion. This is done by setting a minimum interval between responses (a minimum interresponse time), so a response earns reinforcement only if enough time has passed since the previous one. Some formulations describe it as a maximum number of responses in a given period: as long as the count stays at or below that ceiling, each qualifying response is reinforced. The effect is to reduce how often the behavior happens without eliminating it entirely, which is useful when you want to curb a behavior but still allow occasional occurrences. This differs from reinforcing higher rates (which would make the behavior occur more often), from DRD (which reinforces for producing fewer responses than a pre-set criterion over a period), and from a fixed-ratio schedule (which reinforces after a specific number of responses regardless of timing).