What schedule of reinforcement is characterized by varying intervals for reinforcement delivery?

The variable interval schedule is characterized by reinforcement that is provided after an inconsistent amount of time has passed. This means that rewards are given at unpredictable intervals, which encourages consistent responses because the individual does not know exactly when the next reinforcement will be available. This schedule can lead to a high rate of response, as the individual continues to engage in the behavior, hoping to receive reinforcement at any moment.

In contrast, a fixed interval schedule offers reinforcement after a specific, consistent period has elapsed, leading to a predictable pattern of responses. Continuous reinforcement involves providing a reward every time the behavior occurs, which can lead to rapid learning but is not sustainable long-term. A fixed ratio schedule gives reinforcement after a certain number of responses have been made, also providing a predictable pattern but based on the number of actions rather than the passage of time. The variable interval schedule stands out for its unpredictability, which effectively encourages a steady response rate.