Variable ratio
A variable ratio (VR) schedule delivers reinforcement after a number of responses that changes unpredictably around an average, such as an average of every 5th response on VR 5.
On a variable ratio schedule, the number of responses required for each reinforcer varies from one reinforcer to the next, but averages a set value. On a VR 5 schedule, reinforcement might come after 3 responses, then 8, then 4, then 5, then 5, which averages 5. The learner cannot predict which response will be reinforced.
VR schedules typically produce high, steady rates of responding with little or no pause after reinforcement. Behavior maintained on a VR schedule is also very resistant to extinction, because long runs without reinforcement are part of the schedule. Gambling on slot machines is a common everyday example. Reinforcement in everyday life is usually intermittent and unpredictable, which is one reason supervisors thin to variable schedules to help skills maintain outside sessions.
The same features explain why problem behavior that is reinforced only now and then can be so persistent. If a caregiver gives in to whining every few times, unpredictably, whining is on an intermittent schedule similar to VR and may become harder to reduce. For RBTs, implementing a VR schedule usually means following a list or app that tells them which response to reinforce, so that the average matches the plan.
Example and non-example
| Example | On a VR 3 schedule, an RBT praises a client after the 2nd, 5th, 8th and 12th correct responses, following a prepared sequence that averages 3 responses per reinforcer. |
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| Non-example | Praising after exactly every 3rd correct response is a fixed ratio 3 schedule. |
Don't confuse it with
| Fixed ratio | Variable ratio requires a changing number of responses around an average; fixed ratio requires the same number every time. |
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| Variable interval | Variable ratio depends on the number of responses; variable interval depends on varying amounts of time passing. |
Test yourself
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Question 1A plan says to reinforce correct responses after an unpredictable number of them: sometimes after 2, sometimes after 8, and on average after 5. Which schedule is this?
Show answer
C: Variable ratio 5. Reinforcement depends on the number of responses, and that number changes around an average of 5. That is a variable ratio (VR 5) schedule.
- A: A fixed ratio 5 would reinforce after exactly 5 responses every time.
- B: A variable interval schedule depends on time passing, not on a count of responses.
- D: A variable-time schedule delivers reinforcement after varying amounts of time regardless of behavior.
Task C.1 · 40-hour curriculum section A
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Question 2Which schedule of reinforcement typically produces high, steady rates of responding with little pausing after each reinforcer?
Show answer
C: Variable ratio. Because the next reinforcer could come after any response, variable ratio schedules typically produce high, steady response rates with little or no pause after reinforcement.
- A: Fixed interval schedules typically produce a pause after reinforcement and speeding up near the end of the interval.
- B: Fixed ratio schedules typically produce a pause after reinforcement before responding resumes.
- D: Variable interval schedules typically produce moderate, steady rates rather than high rates.
Task C.1 · 40-hour curriculum section A
Answer every question to see your score.
On the RBT exam
This term belongs to task C.1 Positive and negative reinforcement in content area C, Behavior Acquisition, which is 19 of the 75 scored questions.