Which schedule of reinforcement is most resistant to extinction?

• A. Fixed Interval
• B. Fixed Ratio
• C. Variable Interval
• D. Variable Ratio

Answer: (D)

Understanding extinction resistance comes down to how predictable the reinforcement is. In a variable ratio schedule, rewards occur after an unpredictable number of responses, so there isn’t a reliable signal that the next reward is due. This uncertainty keeps the subject responding vigorously because any response could be reinforced, making extinction slow to take hold once rewards stop. That persistence is why variable ratio is the most resistant to extinction.

By contrast, other schedules provide more predictable cues: a fixed ratio rewards after a set number of responses and often produces a pattern of rapid bursts followed by pauses; a fixed interval signals reinforcement after a fixed amount of time, leading to a scalloped pattern and faster drops when reinforcement ends; a variable interval offers unpredictable timing but generally yields less persistent responding than variable ratio.