Which reinforcement schedule is characterized by delivering rewards after an unpredictable number of responses?

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

Answer: (C)

How rewards are given after an unpredictable number of responses shapes a very persistent, high-rate pattern of behavior. When reinforcement comes after a variable number of responses, the next reward could show up at any moment, so the learner keeps responding quickly to try to obtain it. This is the hallmark of a variable ratio schedule.

Think of situations like gambling or sales commissions where rewards don’t come after a fixed count of actions. The uncertainty keeps the effort up, because you never know when the next action will pay off.

If the reward were after a fixed number of responses, you'd see bursts of activity followed by brief pauses (fixed ratio). If reinforcement happened after every response, it would be continuous reinforcement, not unpredictable. If rewards were tied to time (fixed interval), responses would rise near the end of the interval rather than being tied to the number of responses.