What is a Variable Interval (VI)?
Variable Interval (VI) means reinforcement is delivered for the first response after an average amount of time has passed. The time changes.
VI 10-min: You wait 5 mins, then 15 mins, then 10 mins. On average, it is every 10 minutes.
Characteristics
- Produces a steady, constant rate of responding (low to moderate).
- No pauses, no scallops. Just steady work.
RBT Practice Exam Scenario
Question: "Checking your email or text messages is an example of what schedule?"
Answer: Variable Interval (VI). You don't know when the message will arrive (Time Varies). You check steadily throughout the day.
If you check 100 times in 1 minute, it won't make the email arrive faster. That is why the rate is moderate, not high.
Frequently Asked Questions About VI
How does it differ from FI?
FI creates a scallop (pause-and-sprint). VI creates a straight, steady line because you never know when the time is up.
How does it differ from VR?
VR is based on Count (Work harder = get paid faster). VI is based on Time (Work harder = wait anyway). VR produces high rates; VI produces moderate rates.
Who are Pop Quizzes?
Variable Interval. You don't know when they are coming (Time varies), so you must study a little bit every night (Steady rate).