# What is variable interval schedule?

Reinforcement is delivered for the frist response after a variable interval of time??

Relevance

It might be easier to compare Fixed Interval and Variable Interval in order to answer your question.

Fixed Interval - set amount of time (bird gets a cracker every 10 minutes if it pushed the lever.)

Variable Interval - no average time set (bird gets a cracker at some point after it pushes the lever, but the time varies)

Bird pushes lever = cracker in 20 minutes

Bird pushes lever = cracker in 7 minutes

Bird pushes lever = cracker in 11 minutes

Variable interval (VI) schedules deliver reinforcement for the first response after a random average length of time passes since the last reinforcement.

Example: VI3" = reinforcement is provided for the first response after an average of 3 seconds since the last reinforcement.

Lab example: VI10" = a rat is reinforced for the first bar press after an average of 10 seconds passes since the last reinforcement.

Real world example: a predator can expect to come across a prey on a variable interval schedule

• cat
Lv 5