Which schedule is described as reinforcement delivered after an average interval that varies?

Which schedule is described as reinforcement delivered after an average interval that varies?

• A. Variable interval
• B. Fixed interval
• C. Variable ratio
• D. Fixed ratio

Answer: (A)

The concept being tested is how reinforcement timing defines the schedule. When reinforcement is delivered after an average interval that varies, it means the time since the last reinforcement is the trigger, and that interval fluctuates around a mean value. This makes the next reward unpredictable in time, so the behavior tends to stay steady rather than speeding up or waiting for a fixed moment. In this kind of schedule, responses aren’t tied to a specific number; instead, the reward comes after a varying amount of time, on average. That contrasts with a fixed interval, where the reward is guaranteed after a set time, producing bursts of activity near the end of each interval. It also differs from variable ratio, which ties reinforcement to an unpredictable number of responses rather than to time. Likewise, a fixed ratio delivers rewards after a fixed number of responses.

The concept being tested is how reinforcement timing defines the schedule. When reinforcement is delivered after an average interval that varies, it means the time since the last reinforcement is the trigger, and that interval fluctuates around a mean value. This makes the next reward unpredictable in time, so the behavior tends to stay steady rather than speeding up or waiting for a fixed moment.

In this kind of schedule, responses aren’t tied to a specific number; instead, the reward comes after a varying amount of time, on average. That contrasts with a fixed interval, where the reward is guaranteed after a set time, producing bursts of activity near the end of each interval. It also differs from variable ratio, which ties reinforcement to an unpredictable number of responses rather than to time. Likewise, a fixed ratio delivers rewards after a fixed number of responses.