How can we identify a variable interval reinforcement schedule?

How can we identify a variable interval reinforcement schedule?

• A. Reinforcement after a fixed period of time
• B. Reinforcement after a fixed number of responses
• C. Reinforcement, on the average, after every nth minute
• D. Reinforcement after a variable number of responses

Answer: (C)

Variable interval schedules deliver reinforcement after varying time intervals, so the exact moment of reinforcement changes and isn’t predictable in advance. The key is that the interval length is not fixed; it averages to a set duration, but actual intervals fluctuate around that average. This leads to steady, moderate responding because the subject can’t predict when reinforcement will occur. Describing it as reinforcement, on the average, after every n minutes captures this idea: the time until reinforcement varies around a mean of n minutes rather than being a fixed delay. In contrast, a fixed-interval schedule gives reinforcement after a precise amount of time, a fixed-ratio schedule after a set number of responses, and a variable-ratio schedule after a changing number of responses.

Variable interval schedules deliver reinforcement after varying time intervals, so the exact moment of reinforcement changes and isn’t predictable in advance. The key is that the interval length is not fixed; it averages to a set duration, but actual intervals fluctuate around that average. This leads to steady, moderate responding because the subject can’t predict when reinforcement will occur. Describing it as reinforcement, on the average, after every n minutes captures this idea: the time until reinforcement varies around a mean of n minutes rather than being a fixed delay. In contrast, a fixed-interval schedule gives reinforcement after a precise amount of time, a fixed-ratio schedule after a set number of responses, and a variable-ratio schedule after a changing number of responses.