Final answer:
Variable ratio of 7 (VR7) is a type of reinforcement schedule where the number of responses needed for a reward varies. It is commonly observed in activities like gambling where the reward is given after an unpredictable number of actions.
Step-by-step explanation:
Variable ratio of 7 (VR7) is a type of reinforcement schedule where the number of responses needed for a reward varies. In this schedule, the reinforcement is delivered after a random and unpredictable number of responses, typically around 7. An example of VR7 is a slot machine that rewards gamblers after an unpredictable number of pulls on the lever.