What is the basis of a variable-interval schedule?

The basis of a variable-interval schedule is that reinforcement is provided at unpredictable time intervals. This means that the exact timing of the reinforcement varies, making it difficult for the individual to anticipate when the next reward will come. This unpredictability often leads to a steady rate of responding, as the subject is motivated to continue performing the behavior in hopes of receiving reinforcement at some point.

Variable-interval schedules are particularly effective in maintaining behavior over time because they create a sense of uncertainty and the potential for receiving reinforcement unexpectedly, which can enhance persistence in the behavior. For example, checking for a text message or email is commonly associated with a variable-interval schedule, as the sender may respond at any time, leading individuals to check their devices repeatedly.