Learning Through Reinforcement: Training Mice to Press Levers

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Certainly! Here’s a simple operant conditioning experiment that demonstrates the principles of reinforcement and shaping:

Title: Training a Mouse to Press a Lever

Objective: To demonstrate operant conditioning by training a mouse to press a lever using positive reinforcement.

Materials:

  1. A laboratory mouse
  2. A conditioning chamber (Skinner box)
  3. A lever or button inside the chamber
  4. Food pellets (reinforcer)
  5. Recording equipment (optional)

Procedure:

  1. Setting up the Skinner Box:
    • Place the mouse inside the conditioning chamber.
    • Ensure the lever or button is accessible to the mouse.
  2. Baseline Observation:
    • Allow the mouse to explore the chamber.
    • Observe whether the mouse naturally interacts with the lever/button. This establishes a baseline for behavior.
  3. Initial Training:
    • When the mouse interacts with the lever/button (even accidentally), immediately dispense a food pellet into the chamber.
    • Repeat this process until the mouse associates pressing the lever/button with receiving a food pellet.
  4. Reinforcement Schedule:
    • Initially, reinforce the behavior (lever/button pressing) consistently every time it occurs (continuous reinforcement).
    • As the behavior becomes more consistent, gradually switch to a variable ratio reinforcement schedule. For example, reinforce every 2nd, 3rd, or 5th lever press.
  5. Shaping Behavior:
    • If the mouse does not interact with the lever/button naturally, use shaping techniques. This involves reinforcing successive approximations of the desired behavior.
    • For instance, if the mouse shows interest in the lever but doesn’t press it, reinforce any movement toward the lever, then only reinforce when it touches the lever, and finally only reinforce when it presses the lever.
  6. Recording Data (Optional):
    • Record the number of lever/button presses over each session to track the progress of the conditioning.
    • Note any variations in behavior and reinforcement schedule.
  7. Testing:
    • Once the mouse reliably presses the lever/button, test whether it maintains the behavior without continuous reinforcement.
    • Introduce occasional reinforcement to maintain the behavior over time.
  8. Extinction:
    • To demonstrate extinction, stop reinforcing the behavior (stop dispensing food pellets).
    • Observe how the frequency of lever/button presses decreases over time when the reinforcement is removed.

Results:

  • The mouse learns to press the lever/button to receive food pellets.
  • The frequency of lever/button presses increases over successive training sessions.
  • The behavior is maintained through intermittent reinforcement.
  • Extinction results in a decrease in lever/button presses when reinforcement is removed.

Conclusion: This experiment demonstrates the principles of operant conditioning, including reinforcement, shaping, reinforcement schedules, and extinction. It illustrates how behaviors can be learned, strengthened, maintained, and extinguished through the manipulation of consequences.

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