Which schedule delivers reinforcement at unpredictable time intervals, leading to persistent behavior?

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

Answer: (C)

The main idea is how the timing of reinforcement shapes ongoing behavior. A variable interval reinforcement schedule delivers rewards after varying, unpredictable time intervals. Because the exact moment a reward will come isn’t known, the subject keeps responding steadily to maximize chances of getting reinforcement, which leads to persistent, constant behavior even if rewards are sporadic or infrequent.

For contrast, a fixed interval schedule gives reinforcement after a set time, causing responses to cluster as the interval nears its end and then dip right after reinforcement. A continuous reinforcement schedule reinforces every response, which speeds learning but doesn’t promote persistence when reinforcement stops. A fixed ratio schedule reinforces after a fixed number of responses, producing high rates of responding with pauses after each reinforcement.