Which schedule is characterized by reinforcement following a varying number of responses, leading to high and stable response rates?

• A. VARIABLE RATIO
• B. VARIABLE INTERVAL
• C. VARIABILITY
• D. TRIAL TO CRITERION

Answer: (A)

Reinforcement schedules that depend on the number of responses shape how often a behavior is performed. A variable ratio schedule delivers reinforcement after an unpredictable number of responses, with reinforcement occurring on average after a certain number of responses. Because the exact number needed is unknown, the learner can’t predict when reinforcement will come, so they respond at a high and steady rate to maximize the chance of getting reinforced. There’s usually little to no post-reinforcement pause, and the rate remains consistently high until reinforcement occurs.

As a contrast, a variable interval schedule reinforces after varying time intervals, so the response rate tends to be steady but more moderate and includes occasional pauses. A fixed ratio would produce a high response rate but typically a clear post-reinforcement pause after each reinforcement. Trial to criterion isn’t a reinforcement schedule at all; it’s a measure of how many trials are needed to meet a performance criterion.