Contingency and Continuity

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  • Definition one: animal passive, learning= behavior. Reflexive (S-R learning later in class) Do you learn automatically? Definition 2: does not mention the behavior, can you learn something that does not show up in behavior? Views animal as an information processor S-S vs. S-R Hull Tolman
  • e.g. Colwill & Rescorla (1985) Pressing a lever allowed rats to obtain food pellets Pulling a chain gave access to sugar water. One group was given free access to food pellets then made ill When both the lever and chain were present (without reinforcement) this group made few lever presses but continued to pull the chain. Illness after drinking sugar water had the opposite effect. Operant responses are produced because they are associated with their consequence
  • Contingency and Continuity

    1. 1. Operant Conditioning: Causal Factors and Explanations Contingency and Continuity
    2. 2. Conditioning and Learning  Conditioning is the process by which an activity originates or is changed through reacting to an encountered situation provided that the change in activity can not be explained on the basis or native tendencies, maturation or temporary states. Hilgard (1956)  Conditioning is the learning of relations among events so as to allow the organism to represent its environment. Rescorla (1988) S-R S-S
    3. 3. WHAT PRODUCES CONDITIONING: CONTIGUITY OR CONTINGENCY?  Power of reinforcement to shape and sustain operant behavior is pervasive.  So, too, is its potential as a tool in a wide range of practical applications.  But, what is it about response-reinforcer relation that produces conditioning?
    4. 4. Operant Conditioning S+ R O*
    5. 5. WHAT PRODUCES CONDITIONING: CONTIGUITY OR CONTINGENCY?  Two answers have been offered:  Contiguity – Temporal proximity between response and reinforcer  Contingency – Probabilistic relation with reinforcement of responding and not responding  temporal relationship; temporal contiguity refers to the delivery of the reinforcer immediately after the response  causal relationship; response-reinforcer contingency refers to the extent to which the response is necessary and sufficient for the occurrence of the reinforcer
    6. 6. Evidence for Contiguity  Generally, as delay between response and reinforcer increases, rate of operant responding decreases.
    7. 7. Evidence for Contiguity  Generally, as delay between response and reinforcer increases, rate of operant responding decreases.
    8. 8. Evidence for Contiguity  Generally, as delay between response and reinforcer increases, rate of operant responding decreases.  Temporal contiguity is thus necessary for conditioning to occur.  But, is temporal contiguity also sufficient?  Can’t tell because most studies require responses to produce reinforcers.
    9. 9. Evidence for Contiguity  Skinner’s 1948 superstition project :  Studied 8 hungry pigeons.  Food given every 15 sec regardless of pigeon’s behavior.  6/8 pigeons performed idiosyncratic patterns of unnecessary behavior.  Responding rose as time to food approached.  Why did all of this happen?
    10. 10. Evidence for Contiguity  Food happened to follow something each pigeon was doing.  Different behaviors were strengthened for different pigeons.  Higher the rate of response, the more likely food would again follow response.  Responding rose as time to food neared because P of response-food pairing rose the longer the time since last food.
    11. 11. Evidence for Contiguity  Skinner thus concluded that necessary and sufficient condition for operant conditioning was that a reinforcer closely follow a response.  Why is response-reinforcer contingency so effective?  It guarantees response-reinforcer contiguity.
    12. 12. Evidence for Contiguity  Skinner’s results and conclusions have been questioned.  His results may be difficult to replicate.  His conclusions may not be general.  But, beyond superstition experiment, there may be good evidence to support importance of response-reinforcer contiguity.
    13. 13. What leads to conditioning?  Contiguity – Stimuli that are close to one another in time and in space become associated  Co-occurrence – Proximity critical  Contingency – When one stimulus depends on the other, they will become associated  Information – Predictive value critical
    14. 14. Evidence for Contiguity  Thomas (1981) study on contiguity- promoting schedules.  P(Food|Press) = P(Food|No Press)
    15. 15. Trial 1 Trial 2 Trial 1 Trial 2 20s No Response: Subject Responds: Reward S* Reward S* Reward S* Reward S* Bar press R Bar press R
    16. 16. Thomas Schedule p p pp ----/----/----/---- f f f f
    17. 17. Evidence for Contiguity  Thomas (1981) study on contiguity- promoting schedules.  P(Food|Press) = P(Food|No Press)  No press-food contingency.  But, response-food contiguity was promoted by novel schedule.  So too was lever pressing. Rats increased lever pressing
    18. 18. Evidence for Contiguity  Extra wrinkle of Thomas (1981) study:  P(Food|Press) < P(Food|No Press)  Thus, negative press-food contingency.
    19. 19. Trial 1 Trial 2 Trial 1 Trial 2 20s No Response: Subject Responds: Reward S* NO S* Reward S* Reward S* Bar press R Bar press R Rewarded response causes next 20s trial to be unrewarded Trial 4Trial 3
    20. 20. Second Thomas Schedule p p pp ----/----/----/---- f f f
    21. 21. Evidence for Contiguity  Extra wrinkle of Thomas (1981) study:  P(Food|Press) < P(Food|No Press)  Thus, negative press-food contingency.  Response-food contiguity was still promoted by second schedule.  So too was lever pressing. Rats increased lever pressing  Power of contiguity is very strong; can even override effects of contingency.
    22. 22. What leads to conditioning?  Contiguity – Stimuli that are close to one another in time and in space become associated  Co-occurrence – Proximity critical  Contingency – When one stimulus depends on the other, they will become associated  Information – Predictive value critical
    23. 23. Operant Conditioning: Contiguity S+ R O* O* stamps in S+- R relationship Pavlov Hull Skinner
    24. 24. CONTINGENCY LEARNING  Attempts to assess contingency learning in operant conditioning parallel studies in Pavlovian conditioning.  Operant studies suggest that organisms can distinguish dependence from independence between response and reinforcer. Cause and effect
    25. 25. What leads to conditioning?  Contiguity – Stimuli that are close to one another in time and in space become associated  Co-occurrence – Proximity critical  Contingency – When one stimulus depends on the other, they will become associated  Information – Predictive value critical
    26. 26. CONTINGENCY LEARNING  Figure 8.4
    27. 27. Contiguity without Contingency 10 20 20 40 airplane no plane no S* 2 S* 2 a b c d S+ 1 No S+ 1 bird and plane are paired A quick test for contingency a·d > c·b then positive a·d = c·b zero contingency a·d < c·b then negative no bird bird prob. (birdplane) = .33 prob. (birdno plane) = .33 10/30 20/60
    28. 28. You can have a positive contingency even when pairing is the least frequent possibility Example: can you learn that and “cat” are associated? “cat” no “cat” 100 900 1,000 200 9,800 10,000 see no p (“cat” ) = .10 p (“cat”no ) = .02 hear positive contingency Learning: Seeking cause and effect relationships
    29. 29. CONTINGENCY LEARNING  Head turn, mobile, infants given positive contingency procedure (Watson, 1967): – Infants’ head turning increased, plus they smiled when mobile moved  Infants put on zero contingency procedure: – Infants’ head turning did not increase, plus they stopped smiling when mobile moved Apple martinis
    30. 30. Carolyn Rovee-Collier 445-3364
    31. 31. CONTINGENCY LEARNING  Infants discriminate response- dependent from response-independent reinforcement: shown by head turning.  Infants differentially enjoy response- dependent and response-independent reinforcers: shown by smiling and cooing.  Both cognition and affect may be changed by control by consequence. Cause and effect
    32. 32. Learned Helplessness (Seligman)
    33. 33. panel Learned Helplessness (Seligman) Phase I - Learning to Escape Control Dogs Yoked Dogs Shock •A long lasting shock is given to both groups every once in a while •Control dogs can turn shock off by pushing a panel •Yoked dogs’ shock turns off too, when control dog pushes panel •Yoked dogs can do nothing themselves to escape shock
    34. 34. Contiguity or Contingency? Spot  Periodically shocked  Can terminate shock by pressing lever with his nose Lassie  Periodically shocked  Has no control over shocks, but when Spot’s shock is terminated, so is Lassie’s
    35. 35. Phase 2 - Avoidance Learning •shock delivered to one side of box •if dog jumps hurdle to other side there is no shock Control dogs learn to avoid shock Yoked dogs don’t Yoked dogs have learned that they can’t stop shock They have learned to be helpless hurdle
    36. 36. Learned Helplessness  Yoked dog seems to have learned that its behavior does not matter: – It not only fails to learn – It stops reacting to shock  Phenomenon of learned helplessness strongly suggests that organisms can discriminate response-dependent from response-independent events.
    37. 37. Learned Helplessness  Animals must learn to jump barrier to avoid shock  Results – Spot learns, Lassie yelps but eventually becomes passive and accepts shocks  Contingency – Spot learns his actions matter – Lassie learned that it was helpless  Contiguity – Spot learned to press lever – Lassie learned to act passively
    38. 38. Seligman’s Learned Helplessness Study  Two groups of dogs are exposed to shock – control group could escape shock – “no escape” group could NOT escape shock  Later, when escape was possible, “no escape” dogs didn’t even try  Learned that they had NO CONTROL
    39. 39. OPERANT CONDITIONING: WHAT IS LEARNED?  In any operant conditioning study, three events need to be considered: – Response (R) – Reinforcer or punisher it produces (O*) – Stimulus situation in which response occurs (S) – Three occur in S-R-S* sequence  What associations among three elements are formed when animal learns to make operant response?
    40. 40. OPERANT CONDITIONING: WHAT IS LEARNED?  R-O* association  Seems to require foresight: acting in accord with future consequences.  Thorndike famously denied that animals know what consequence of their behavior will be.  Law of effect thus emphasized past consequences.
    41. 41. Operant Conditioning S+ (R O*)
    42. 42. OPERANT CONDITIONING: WHAT IS LEARNED?  S+ -R association  Thorndike’s idea  Situation evokes behavior (S-R).  Reinforcers strengthen S-R bond.  S+ becomes more likely to evoke R.
    43. 43. Operant Conditioning: Contiguity S+ R O* O* stamps in S+- R relationship Pavlov Hull Skinner
    44. 44. OPERANT CONDITIONING: WHAT IS LEARNED?  Two-process theory: – S-R association (operant) – S-O* association (Pavlovian)  Sight of lever not only triggers lever pressing, but it also makes animal “think” about upcoming food.  Anticipation of reinforcer motivates operant response.
    45. 45. OPERANT CONDITIONING: R-S* Learning  Strongest evidence comes from studies using devaluation procedure (Colwill & Rescorla, 1985).  Chain Pull→Sugar Water  Lever Press→Food Pellet  Food Pellet→Illness (Devaluation)  Choice: chain pull versus lever press  Rats pull chain much more than press lever.
    46. 46. R-O* association Colwill & Rescorla (1985) Training Devaluation Test R1 O1 R2 O2 O1 LiCL O2 nothing R1 and R2 1 2 3 4 5 6 7 Mean resp/min R1 -outcome was devalued Time R2 -outcome not devalued
    47. 47. OPERANT CONDITIONING: R-O* Learning  Association of food with illness does not change stimulus aspects of situation that might generate responses.  Lever press does not occur because it is associated with chamber (S-R), but because it is associated with reinforcer (R-S*).  When value of reinforcer is eliminated, so too is impetus for response.
    48. 48. OPERANT CONDITIONING: R-O* Learning  Operant conditioning involves learning to expect responses to produce reward.  Rats not only expect reward, but a particular kind of reward.  Devaluation procedure could not work unless rats had specifically remembered that one response produced food pellets and other produced sugar water.
    49. 49. Operant Conditioning (S+ ) R (O*)
    50. 50. OPERANT CONDITIONING: S-O* Learning  Rats trained to panel press.  A light or noise was always present.  S1 = sugar water and S2 = food pellets.  Lever press = sugar water and chain pull = food pellets.  S1 increased lever pressing, but not chain pulling.  S2 increased chain pulling, but not lever pressing.
    51. 51. S-O* Learning
    52. 52. OPERANT CONDITIONING: S-O* Learning  For rat to show these selective increases in responding, it must have learned which stimulus was associated with which reward.  Therefore, this study provides evidence of S-O* associations in operant conditioning (Colwill & Rescorla, 1988).
    53. 53. S-O association Colwill & Rescorla (1988) Sd training Response training Test S1 R1 O1 S2 R2 O2 R3 O1 R4 O2 S1: R3 vs R4 S2: R3 vs R4 2 4 6 10 Mean resp/min Different outcome Trials Same outcome 8
    54. 54. OPERANT CONDITIONING: S-R Learning  Devaluation studies find a reduction in response that leads to devalued reward.  But, response is rarely eliminated.  Residual responding may represent behavior triggered by stimulus situation in which responding was rewarded.
    55. 55. OPERANT CONDITIONING: WHAT IS LEARNED?  Summary statement:  Research suggests organisms learn associations between response and reinforcer (R-O*), environmental stimuli and reinforcer (S-O*), and stimuli and response (S-R).  The “simple” process of operant conditioning is not so simple after all.

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