Principles of Behavior Sixth Edition

1. Principles of BehaviorSixth Edition Richard W. Malott Western Michigan University Power Point by Nikki Hoffmeister

2. Chapter 17 Ratio Schedules

3. What is a Schedule of Reinforcement? Schedule of Reinforcement: • The way reinforcement occurs • because of the number of responses, • time between responses, • and stimulus conditions.

4. What is Continuous Reinforcement? Continuous Reinforcement (CRF): • A reinforcer follows each response. • Intermittent Reinforcement: • Reinforcement occurs, but not after each response.

5. When should you use CRF? • Continuous reinforcement is usually best for shaping or maintaining difficult behavior. • Shaping vocal responses

6. What is a Fixed-Ratio Schedule? Fixed-Ratio (FR) Schedule of Reinforcement: • A reinforcer follows • a fixed number of responses.

7. What kind of responding does a fixed-ratio schedule produce? Fixed-Ratio Responding: • After a response is reinforced, • no responding occurs for a period of time, • then responding occurs at a high, steady rate • until the next reinforcer is delivered.

8. Non-Cumulative Graph

9. Non-Cumulative Graph • The horizontal line (x-axis) indicates the passage of time • Each vertical line indicates a response • At the end of each ratio of 8 responses a reinforcer is delivered (indicated by star) • After each star, the line is flat, indicating no response occurs for a while • Post-reinforcement pause

10. Post-Reinforcement Pause • Characteristic of fixed-ratio-maintained behavior • The length of the pause is proportional to the size of the ratio

11. High Ratios • If you wish to establish a high ratio requirement, • you need to do so gradually, • raising the ratio from 2 to 4 to 6 responses and up. • Otherwise the response may extinguish.

12. What is the general rule for establishing intermittently reinforced behavior? • First, use continuous reinforcement • and gradually increase the intermittency of reinforcement • as responding stabilizes at a high rate.

13. The Cumulative Graph

14. Cumulative Graph • Behavior analysts often use this type of graph when studying schedules of reinforcement. • The vertical axis (ordinate) is labeled cumulative frequency of responses as opposed to a non-cumulative graph in which the ordinate is labeled responses. • The post-reinforcement pause is where the slope of the line is zero.

15. What is a Variable Ratio Schedule? Variable-Ratio (VR) Schedule of Reinforcement: • A reinforcer follows • after a variable number of responses.

16. What type of responding does a VR schedule produce? Variable-Ratio Responding: • Variable-ratio schedules produce • a high rate of responding, • with almost no post-reinforcement pausing.

17. VR Schedules • VR 50 • This means that a reinforcer is delivered after an average of 50 responses • An FR 50 means the reinforcer is delivered after exactly 50 responses • Intermittent Reinforcement: • Generic term that includes both fixed and variable ratio schedules

18. Reinforcer vs. Reinforcement • What is a specific pellet of food for a deprived rat? • A reinforcer • Reinforcement • The immediate delivery of a pellet contingent on a deprived rat’s lever press with a resulting increased rate of pressing? • Reinforcer • Reinforcement

19. Reinforcer vs. Reinforcement • What is a quarter for a deprived professor? • Reinforcer • Reinforcement • What is the immediate delivery of a quarter, contingent on a deprived prof’s pleading for a raise, with a resulting increased rate of pleading? • Reinforcer • Reinforcement

20. Ratio Schedules in Everyday Life • Are slot machines in casinos examples of everyday VR schedules? • No; there are 5 reasons why

21. 4 Reasons Why Slot Machines are Not VR Schedules • It’s loaded with learned reinforcers in addition to the silver dollars • Like those fruits that appear in the window, one after the other • You get 2 cherries in a row…a big reinforcer

22. 4 Reasons Why Slot Machines are Not VR Schedules • The variable amount of the reinforcer you get at the end of the so-called VR • Sometimes you get only one silver dollar • Sometimes it’s 10, 18, so on • None of that’s like the ratios the behavior analysts study in the Skinner box

23. 4 Reasons Why Slot Machines are Not VR Schedules • The size of the ratio is much smaller than is typical in the Skinner box of the professional research lab • Like a VR 100 • In a casino, people would not play if machines had ratios of 100

24. 4 Reasons Why Slot Machines are Not VR Schedules • The emotional reaction is itself reinforcing • Near misses are reinforcing

25. Intermediate Enrichment • Free-operant procedures • Most Skinner-box research involves free-operant responding • The animal is free to respond at various frequencies (1 lever press per minute to 100 lever presses per minute) • There is no S∆ after each response, so there is no inter-trial interval between each response and the next SD

26. Discrete-Trial Procedure • There is an SD, • a single response, • and an outcome, • followed by an S∆ (intertrial interval); • then the next trial starts.

27. In the Classroom:Discrete-Trial Procedure SD: Sue says, “Jimmy point to the horse.” Response: Jimmy points to the horse. Outcome: Sue says, “Good boy, Jimmy.” (a learned reinforcer for Jimmy) S∆ (Inter-trial Interval): Sue says nothing

28. In the Classroom:Free-Operant Procedure SD: Sue and Jimmy at the snack table. Response 1: Jimmy says, “Juice please.” Outcome: Sue gives him a sip of juice. Response 2: Jimmy says, “Juice, please.” Outcome: Again, Sue gives him a sip of juice. S∆: Sue and Jimmy leave the snack table.

29. Discrete Trial vs. Free Operant

30. Advanced Enrichment • Hybrid Discrete-Trial/Free-Operant Procedure • Each free-operant response, itself, consists of a discrete trial.

31. Example • Sue and Jimmy are in the structured-play area Response 1: Jimmy picks up a piece of the puzzle and puts it in the puzzle form Response 2: Jimmy picks up a 2nd piece and puts it in the puzzle form Response 3: Jimmy picks up a 3rd, final piece, and puts it in the form Outcome: Jimmy has completed the puzzle and sees a picture of Barney. Sue says, “Good job.”

32. Why Hybrid? • This is an example of a discrete trial, because each piece Jimmy puts in the puzzle is an SD for the next response. • It is also an example of free operant because Jimmy is free to place each puzzle piece as fast as he “wants,” and… • A measure of his behavior would be a rate measure (e.g., 8 pieces per minute).

33. On DickMalott.com • Chapter 17 Advanced Enrichment Section • In Search of the Everyday Variable Ratio

34. Join us for Chapter 18:Interval Schedules