Which schedule is known for unpredictable timing and tends to make the subject persist in seeking rewards?

• A. Variable Interval Reward Schedule
• B. Fixed Interval Reward Schedule
• C. Fixed Ratio Reward Schedule
• D. Continuous Reward Schedule

Answer: (A)

This item tests how unpredictable reinforcement timing affects persistence of seeking rewards. When rewards are delivered after varying, unpredictable intervals, the subject never knows when the next reward might come, so they keep responding steadily in the hope that a reward is soon. That uncertainty creates strong persistence and a high resistance to extinction—the behavior tends to continue even if rewards become less frequent.

This contrasts with other patterns: a fixed interval schedule produces responses that speed up as the interval nears its end, then pause after a reward, because the timing is predictable. A fixed ratio schedule rewards after a set number of responses, driving high response rates but linking behavior to the amount of work rather than timing. A continuous schedule gives a reward for every response, leading to rapid learning but poor persistence once rewards stop, since there’s no uncertainty to drive continued seeking.