Which is an example of a fixed ratio schedule?

A fixed ratio schedule refers to a reinforcement strategy where a reward is delivered after a predetermined number of responses. This means that the subject must exhibit a specific behavior a set number of times before receiving reinforcement. In this case, "reinforcing behavior after every 3 responses" demonstrates a fixed ratio schedule because it ties the reinforcement directly to a defined number of responses, which is three.

This approach is effective because it establishes a clear expectation for the subject, leading to consistent performance and often a high rate of responding as the individual works towards the reward. The predictability of this schedule can encourage the behavior to be repeated, as the individual knows exactly what is required to obtain the reinforcement.

The other options describe different reinforcement schedules. Reinforcing behavior every 5 minutes represents a fixed interval schedule, where the time between reinforcements remains constant regardless of the number of responses. Reinforcing behavior randomly aligns more with a variable interval schedule, where reinforcements are given at unpredictable times. Lastly, the variable time intervals involve changing the duration between reinforcements, making it another form of a variable schedule. Each of these alternatives fundamentally differs from the concept of a fixed ratio schedule, highlighting the importance of consistency in reinforcement tied to the number of responses.