Which schedule of reinforcement is described as delivering reinforcement after a response occurs if a minimum interresponse time has elapsed?

• A. DRD
• B. DRL
• C. DRH
• D. FR

Answer: (B)

Reinforcement that depends on spacing between responses is the idea here. In a differential reinforcement of low rate (DRL) schedule, reinforcement is given only if the time since the previous response meets or exceeds a set minimum interresponse time. That means you have to pause long enough between responses for another response to be reinforced, which slows overall responding. The other schedules don’t fit: a high-rate schedule reinforces only when responses occur quickly or at a high frequency, a fixed-r ratio reinforces after a fixed number of responses regardless of timing, and diminishing rate (DRD) reinforces reductions in overall rate but not by enforcing a specific minimum pause after every response.