Under what conditions is a response reinforced in a fixed interval reinforcement schedule?

In a fixed interval reinforcement schedule, a response is reinforced after a specific amount of time has elapsed. This means that reinforcement is delivered following the completion of a designated time period, regardless of the number of responses made during that interval. For example, if a reinforcement is set to occur every 5 minutes, a behavior will only be reinforced after that 5-minute time period has passed, regardless of how many times the behavior occurred within that timeframe. This creates a pattern where responses tend to increase as the time for reinforcement approaches, leading to what is often described as a "scalloped" pattern in behavior.