6.11 Study Notes on Schedules of Reinforcement

Reinforcement Schedules

Overview of Schedules of Reinforcement

  • Definition: Schedules of reinforcement refer to the rules that determine when reinforcement (rewards) becomes available.
  • Key Question: When do we expect a reward?
  • Main Types:
    • Continuous Reinforcement
    • Partial Reinforcement

Continuous vs. Partial Reinforcement

  • Continuous Reinforcement:

    • Definition: Reinforcement occurs every single time a behavior is performed.
    • Example: Vending machines that dispense a product every time money is inserted and a selection is made, given the machine is functional.

  • Partial Reinforcement:

    • Definition: Reinforcement occurs after an intermittent number of behaviors or after an intermittent amount of time.
    • Example: Slot machines or video lottery terminals (VLTs) operate under partial reinforcement schedules, where payouts are not guaranteed on every attempt, perhaps occurring on every 100th or 1000th attempt.

Types of Partial Reinforcement Schedules

  • Ratio Schedules:
    • Defined by the number of behaviors required to receive reinforcement.
  • Interval Schedules:
    • Defined by the amount of time that must pass before reinforcement becomes available.
  • Fixed vs. Variable Schedules:
    • Fixed: More predictable schedules of reinforcement.
    • Variable: Less predictable, more fluctuating schedules.

Fixed Schedules Explained

  • Fixed Ratio Schedule:

    • Definition: Reinforcement is delivered after a predictable, specified number of behaviors are performed.
    • Example:
    • In an operant chamber, a rat is placed on a fixed ratio schedule of 10. The rat must press the lever 10 times to receive food reinforcement.
    • After each cycle of 10 presses, the rat will have to press another 10 times for additional reinforcement, leading to a steady state of responding.
    • Real World Example: Loyalty cards in stores that offer a free item (like a meal or drink) after a number of purchases (e.g., buy 9 items, get the 10th free).

  • Fixed Interval Schedule:

    • Definition: Reinforcement is available after a predictable period of time has passed.
    • Example:
    • If the rat is on a fixed interval schedule of 100 seconds, it must wait 100 seconds before being able to press the lever to receive food. After each interval, another 100 seconds must pass before the next reinforcement is available.
    • Response Pattern:
    • This schedule produces a scalloped pattern of responding where the rat increases its responses as the next reinforcer becomes available, with slow responses following reinforcement periods.
    • Real World Example:
    • Mobile games, such as Pokemon Go, where players can collect items only after a certain interval (e.g., spin a Pokestop every 5 minutes).
    • Student Behavior:
      • Similar to study habits, where students often study more as exams approach, leading to a pattern of increased study behavior as deadlines near, correlating to the scalloped pattern observed in fixed interval schedules.