Final answer:
Teaching assistants receiving a monthly pay demonstrate a fixed interval reinforcement schedule, where payment is not tied to the amount or quality of work but rather occurs at regular, predictable intervals.
Step-by-step explanation:
The payment plan for teaching assistants, where they receive a set amount of money once a month regardless of their performance, is an example of a fixed interval reinforcement schedule.
This reinforcement schedule rewards behavior after a set amount of time has elapsed, rather than being dependent on the number of responses or the quality of the work.
In this case, the fact that teaching assistants get paid monthly for their work is analogous to June receiving pain medication on a fixed schedule post-surgery, as described in the provided information.