Quiz #3

1. Quiz #3 • Last class, we talked about 6 techniques for self-control. Name and briefly describe 2 of those techniques.

2. Chapter 10 Schedules of Reinforcement

3. Schedule of Reinforcement • Delivery of reinforcement • Continuous reinforcement (CRF) • Fairly consistent patterns of behaviour • Cumulative recorder

4. Cumulative Record • Use a cumulative recorder • No response: flat line • Response: slope • Cumulative record

5. roller roller Cumulative Recorder pen paper strip

6. Recording Responses

7. The Accumulation of the Cumulative Record VI-25

8. Schedules: • 4 Basic: • Fixed Ratio • Variable Ratio • Fixed Interval • Variable Interval • Others and mixes (concurrent)

9. reinforcement no responses responses “pen” resetting Fixed Ratio (FR) • N responses required; e.g., FR 25 • CRF = FR1 • Rise-and-run • Postreinforcement pause • Steady, rapid rate of response • Ration strain slope

10. Variable Ratio (VR) • Varies around mean number of responses; e.g., VR 25 • Rapid, steady rate of response • Short, if any postreinforcement pause • Longer schedule --> longer pause • Never know which response will be reinforced

11. Fixed Interval (FI) • Depends on time; e.g., FI 25 • Postreinforcement pause • Scalloping • Time estimation • Clock doesn’t start until reinforcer given

12. Variable Interval (VI) • Varies around mean time; e.g., VI 25 • Steady, moderate response rate • Don’t know when time has elapsed • Clock doesn’t start until reinforcer given

13. Response Rates

14. Duration Schedules • Continuous responding for some time period to receive reinforcement • Fixed duration (FD) • Period of duration is a set time period • Variable duration (VD) • Period of duration varies around a mean

15. Differential Rate Schedules • Differential reinforcement of low rates (DRL) • Reinforcement only if X amount of time has passed since last response • Sometimes “superstitious behaviours” occur • Differential reinforcement of high rates (DRH) • Reinforcement only if more than X responses in a set time • Or, reinforcement if less that X amount of time has passed since last response

16. Noncontingent Schedules • Reinforcement delivery not contingent upon a response, but on passage of time • Fixed time (FT) • Reinforcer given after set time elapses • Variable time (VT) • Reinforcer given after some time varying around a mean

17. Stretching the Ratio • Increasing the number of responses • e.g., FR 5 --> FR 50 • Extinction problem • Use shaping • Increase in gradual increments • e.g., FR 5, FR 8, FR 14, FR 21, FR 35, FR 50 • “Low” or “high” schedules

18. Extinction • CRF (FR 1) easiest to extinguish than intermittent schedules (anything but FR 1) • Partial reinforcement effect (PRE) • High schedules harder to extinguish than low • Variable schedules harder to extinguish than fixed

19. Discrimination Hypothesis • Difficult to discriminate between extinction and intermittent schedule • High schedules more like extinction than low schedules • e.g., CRF vs. FR 50

20. Frustration Hypothesis • Non-reinforcement for response is frustrating • On CRF every response reinforced, so no frustration • Frustration grows continually during extinction • Stop responding, stop frustration (neg. reinf.) • Any intermittent schedule always some non-reinforced responses • Responding leads to reinforcer (pos. reinf.) • Frustration = S+ for reinforcement

21. Sequential Hypothesis • Response followed by reinf. or nonreinf. • On intermittent schedules, nonreinforced responses are S+ for eventual delivery of reinforcer • High schedules increase resistance to extinction because many nonreinforced responses in a row leads to reinforced • Extinction similar to high schedule

22. Response Unit Hypothesis • Think in terms of behavioural “units” • FR1: 1 response = 1 unit --> reinforcement • FR2: 2 responses = 1 unit --> reinforcement • Not “response-failure, response-reinforcer” but “response-response-reinforcer” • Says PRE is an artifact

23. Mowrer & Jones (1945) 300 250 200 150 100 50 • Response unit hypothesis • More responses in extinction on higher schedules disappears when considered as behavioural units Number of responses/units during extinction FR1 FR2 FR3 FR4 absolute number of responses number of behavioural units

24. Complex Schedules • Multiple • Mixed • Chain • Tandem • cooperative

25. Choice • Two-key procedure • Concurrent schedules of reinforcement • Each key associated with separate schedule • Distribution of time and behaviour • The measure of choice and preference

26. Concurrent Ratio Schedules • Two ratio schedules • Schedule that gives most rapid reinforcement chosen exclusively • Rarely used in choice studies

27. Concurrent Interval Schedules • Maximize reinforcement • Must shift between alternatives • Allows for study of choice behaviour

28. Interval Schedules • FI-FI • Steady-state responding • Less useful/interesting • VI-VI • Not steady-state responding • Respond to both alternatives • Sensitive to rate of reinforcemenet • Most commonly used to study choice

29. Alternation and the Changeover Response • Maximize reinforcers from both alternatives • Frequent shifting becomes reinforcing • Simple alternation • Concurrent superstition

30. Changeover Delay • COD • Prevents rapid switching • Time delay after “changeover” before reinforcement possible

31. Herrnstein’s (1961) Experiment • Concurrent VI-VI schedules • Overall rates of reinforcement held constant • 40 reinforcers/hour between two alternatives

32. The Matching Law • The proportion of responses directed toward one alternative should equal the proportion of reinforcers delivered by that alternative.

33. Proportional Rate of Reinforcement Proportional Rate of Response R1 = reinf. on key 1 R2 = reinf. on key 2 B1 = resp. on key 1 B2 = resp. on key 2 B1 B1+B2 R1 R1+R2 20 20+20 = = = 0.5 Key 1 Key 2 VI-3min Rein/hour = 20 Resp/hour = 2000 VI-3min Rein/hour = 20 Resp/hour = 2000 2000 2000+2000 = 0.5 MATCH!!!

34. Proportional Rate of Reinforcement Proportional Rate of Response R1 = reinf. on key 1 R2 = reinf. on key 2 B1 = resp. on key 1 B2 = resp. on key 2 B1 B1+B2 R1 R1+R2 6.7 6.7+33.3 = = = 0.17 Key 1 Key 2 VI-9min Rein/hour = 6.7 Resp/hour = 250 VI-1.8min Rein/hour = 33.3 Resp/hour = 3000 250 250 + 3000 = 0.08 NO MATCH  (but close…)

35. Bias • Spend more time on one alternative than predicted • Side preferences • Biological predispositions • Quality and amount

36. Varying Quality of Reinforcers • Q1: quality of first reinforcer • Q2: quality of second reinforcer

37. Varying Amount of Reinforcers • A1: amount of first reinforcer • A2: amount of second reinforcer

38. Combining Qualities and Amounts

39. Applications • Gambling • Reinforcement history • Economics • Value of reinforcer and stretching the ratio • Malingering