Final answer:
Peter is on a fixed ratio reinforcement schedule since he receives payment after a set number of calls, which is a predictable and consistent reinforcement pattern.
Step-by-step explanation:
Peter experiences a fixed ratio reinforcement schedule in which there are a set number of responses that must occur before the behavior is rewarded. Specifically, Peter is paid $1.00 for every five calls he makes, which aligns with this type of reinforcement schedule because a certain number of actions (telephone calls) leads to a consistent reward (payment). Unlike variable schedules, which are unpredictable, Peter's reinforcement schedule is predictable as it is based on a specific number of responses.