A schedule where reinforcement occurs after an unpredictable number of responses is called?

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

Answer: (C)

This is about how reinforcement is scheduled based on the number of responses. An unpredictable number of responses before reinforcement points to a variable-ratio schedule. Since the exact number of responses needed changes each time, the learner can’t predict when the next reinforcement will come, so they tend to respond at a high, steady rate with little pause after reinforcement. This unpredictability in how many responses are required keeps the motivation high because the reward could come at any moment.

Why the others don’t fit: a fixed-ratio schedule reinforces after a set number of responses, so the pattern is predictable and often followed by a brief pause after reinforcement. An interval schedule depends on time rather than the number of responses, with fixed-interval showing a clear waiting pattern and a post-reinforcement lull; variable-interval makes timing unpredictable but isn’t tied to a specific count of responses. The defining feature here is the unpredictable number of responses required, which points to the variable-ratio schedule.