What is a Variable Ratio (VR)?

Variable Ratio (VR) means reinforcement is delivered after an average number of responses. The number changes (varies) from trial to trial, but averages out to the target.

VR5: You might reinforce after 3, then 7, then 5, then 2. The average is 5.

Characteristics

VR is the Strongest Basic Schedule.
- Creates a steep, steady line on a graph.
- NO Post-Reinforcement Pause. Why? Because the very next response might be the winner. The learner never knows, so they keep working.

RBT Practice Exam Scenario

Question: "Playing a Slot Machine is an example of what schedule?"
Answer: Variable Ratio (VR). You put coins in (Responses) and you win sometimes, but you never know when. This keeps you playing for hours.

Frequently Asked Questions About VR

Why is VR the "strongest" schedule?

It is the most resistant to extinction. Even if you don't win for a while, you keep going because "the next one could be it."

Does it have a pause?

No. The unpredictability keeps the learner engaged constantly.

How do I calculate the VR number?

Add up all the responses required and divide by the number of reinforcements. (e.g., 3+7+5 = 15. 15 / 3 rewards = VR5).