Lecture on Partial Reinforcement Schedules

Definition of Partial Reinforcement

• Partial reinforcement: Behavior reinforced only some of the time
• More resistant to extinction than continuous reinforcement
• Shapes behavior through continuous reinforcement of successive approximations

Importance of Partial Reinforcement Schedules

• Continuous reinforcement becomes less effective over time
• Partial schedules vary in ability to maintain learned behaviors
• Discovered by B.F. Skinner
• Apply to both animals and humans

Four Schedules of Partial Reinforcement

1. Ratio (Amount of Responses) vs. Interval (Time)
   • Ratio: Reinforcement based on the amount of responses (e.g., ration of food)
   • Interval: Reinforcement based on time elapsed
2. Fixed vs. Variable
   • Fixed: Consistent reinforcement
   • Variable: Reinforcement varies

Fixed Ratio Schedule

• Definition: Reinforcement after a fixed number of responses
• Example: Car salesman gets a bonus for every 5 cars sold
• Characteristics:
  • High rate of behavior
  • Common in fast-paced jobs (e.g., factory workers, fruit pickers)

Fixed Interval Schedule

• Definition: Reinforcement after a consistent amount of time
• Example: Car salesman receives paycheck every 2 weeks regardless of number of cars sold
• Characteristics:
  • Slower rate of responding compared to fixed ratio

Variable Ratio Schedule

• Definition: Reinforcement after an average number of correct responses
• Example: Car salesman's bonus varies; may need to sell 5, then 3, then 7 cars, etc.
• Characteristics:
  • Uncertainty in reinforcement
  • High rate of behavior due to unpredictability (e.g., slot machines)

Variable Interval Schedule

• Definition: Responses reinforced after a variable amount of time
• Example: Supervisor gives car salesman a bonus randomly as long as he's engaging with customers
• Characteristics:
  • More regular rate of response than fixed interval

Summary

• Each schedule has a different impact on behavior
• Understanding these can help identify patterns in daily life