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Extinction of Conditioned Behaviour

Extinction of Conditioned Behaviour. Extinction. CS without US Response without outcome Not simply a reversal of acquisition Not the same as forgetting New learning An “inhibitory relationship”. Real Life. Common (and necessary!) occurrence Adaptation to changed conditions

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Extinction of Conditioned Behaviour

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  1. Extinction of Conditioned Behaviour

  2. Extinction • CS without US • Response without outcome • Not simply a reversal of acquisition • Not the same as forgetting • New learning • An “inhibitory relationship”

  3. Real Life • Common (and necessary!) occurrence • Adaptation to changed conditions • E.g., Stop calling a friend after they stop returning calls

  4. Effects of Extinction • Continue original behaviour for a time • Increase behaviour • Vary behaviour • E.g., Call friend more; wait for friend after work.

  5. Neuringer et al. (2001) • Rats, operant chamber • Two levers and a key • Three responses in a row to receive food • Group 1: had to vary response pattern • Group 2: no variation required (yoked) • Acquisition phase • Put on extinction

  6. Results • Variation in behaviour • Change in response rate

  7. Emotional Effects • Frustration • Emotional reaction induced by withdrawal of expected reinforcer • Intensifies behaviour • Aggression

  8. Tomie et al. (1993) • Rats • Water deprived • 3 min. VT-30sec delivery of water • 3 min. no water (ext.), signaled by tone (S-) • Target bite bar (plexiglass wrapped in tape) • Target biting a sign of frustration in rats; readily produced by delivering aversive stimulus (e.g., Azrin et al. 1968)

  9. Results

  10. Azrin et al. (1966) • Pigeons • Conditioned to peck key under alternating periods of food reinforcement and extinction • Restrained pigeon or stuffed pigeon model in chamber attacked during extinction

  11. Design

  12. Attack Behaviour • Cumulative records of 3 pigeons • Pen stepped up for each 1 sec. of attack

  13. Length of Attacks • Average duration of attack post termination of food reinforcement for different pigeons

  14. Stuffed Model • Remarkably similar behaviour

  15. Number of Food Deliveries • Number of food reinforcements before extinction implemented • 0, 1, 3, 5, 10, or 30 food deliveries • Stuffed pigeon • Positive correlation between amount of food and attack duration

  16. Data

  17. Implications for Therapy • Extinction acts as aversive • Aversives create frustration • Frustration can produce aggressive behaviour • Directed against: therapist, anyone in proximity, self

  18. Extinction and Original Learning • Not a reversal • Forgetting a different underlying process • Actually a new acquisition of learning

  19. Disinhibition • Fully condition CS with US • Impose extinction protocol • Present novel stimulus along with extinguished CS • CR will reoccur

  20. Why “Disinhibition”? • Pavlov’s terminology • Excitatory conditioning • Increase in excitatory strength • Extinction • Inhibition of excitatory conditioning • Net sum effect • Full extinction = excitation + inhibition = 0

  21. Disinhibition inhibits the “extinction inhibition” • Temporarily reduces strength of inhibition • Excitation + (inhibition + disinhibition) > 0 • A temporary effect

  22. Parallels Dishabituation • Temporary return of habituated response without rest period • Three ways • New stimulus presented with habituated stimulus (e.g., Graves & Thompson, 1970) • Change habituated stimulus (e.g., Fisher, 1962 with the Coolidge effect) • Change context of habituation (e.g., Schein & Hale, 1974) • Temporary sensitization process superimposed over habituation process

  23. Spontaneous Recovery: Classical • Fully condition CS-US • Fully extinguish CS • Let some time pass • Present CS • Will get return of CR

  24. Rescorla (1997) • Goal tracking for two different CSs • Full conditioning for all groups followed by full extinction • CS-Rest: test session 8 days after extinction • CS-No Rest: test session immediately after extinction • Pre-CS: control group

  25. Results

  26. Spontaneous Recovery: Operant • Condition three term contingency • Extinguish response • Allow time to pass • Response will return in presence of SD

  27. Rescorla (1996) • Rats • Responses (lever press or nose poke) acquired, then extinguished • R-Rest: tested 7 days post-extinction • R-No rest: tested shortly after extinction

  28. Results

  29. Renewal • Recovery of acquisition of performance when context cues present during extinction are changed • If extinction is learning another three term contingency, then changing the cues eliminates the SD for extinction • Think of this in terms of stimulus control

  30. Bouton & King (1983) • Rats press lever for food • Tone (CS) paired with footshock • Training in two chambers • Post training, 20 extinction trials • Group 1 in original (A) chamber • Group 2 in novel (B) chamber • Group 3 had no extinction (control) • All groups tested for response in chamber A

  31. Results

  32. Renewal Also In: • Classical appetitive conditioning • Conditioned inhibition • Instrumental conditioning • Physiological states, such as from drugs can also act as the SD for extinction that can be renewed (e.g., Bouton et al., 1990)

  33. Reinstatement • Recovery of the excitatory responding to an extinguished stimulus produced by exposure to the US • Example: fear of flying • Extinguish fear through therapy • Have one frightening flying experience • Phobia re-established to high level

  34. Bouton (1984) • Conditioned suppression in rats • US = shock • Boulton suggests reinstatement may be subset of renewal (US activates context cues)

  35. Sensitivity to US Devaluation • Utilize US devaluation to determine if CS-US association persists through extinction • Show S-R and R-O association maintained post-extinction

  36. Study Design • Two CS (light, tone), two US (food, sucrose) • Counterbalanced across subjects • US devaluation via LiCl • Note: need to recondition extinguished CSs to different US to get measurable CR in test

  37. Results NotDev • Extinguished group shows weaker CR • Within groups, devalued stimulus shows even weaker CR; pre-extinguished CS-US association still affected NotDev Dev Light CR Strength Tone Dev Extinguished Not extinguished

  38. Study Design • Different responses, different outcomes • Note: recondition R1 & R2 to new O pre-devaluation

  39. Results NotDev. NotDev. O2 Resposnes O1 Dev. Dev. Extinguished Not Extinguished

  40. Enhancing Extinction • So extinction doesn’t actually eliminate prior learning • Sometimes extinguished response comes back • Techniques to minimize return of extinguished learning

  41. Number & Timing • More extinction trials! • Space extinction trials closer together (massed) rather than spread out (spaced) • Works with aversive conditioning; don’t really know about appetitive conditioning yet

  42. Reducing Spontaneous Recovery • Repeat periods of rest and testing • Less recovery with each successive cycle • Manipulating interval between acquisition and extinction • Fear conditioning study found less spontaneous recovery with shorter interval • Appetitive conditioning study found the opposite • Present cues associated with extinction • Reactivates extinction performance

  43. Reducing Renewal • Conduct extinction in multiple settings • Increases stimulus generalization • Present SD for extinction during renewal

  44. Compound Extinction Stimuli • Present two stimuli undergoing extinction simultaneously

  45. Rescorla (2006) • Rats • Three stimlui: Light, Noise, Tone • Acquisition of lever pressing (VI30 sec.) in presence of stimuli • Extinguish each of the stimuli • Compound extinction phase • Light with one of auditory stimuli; other auditory alone

  46. Elevated responding (summation of subthreshold responding remaining to L & A1) Substantial spontaneous recovery of A2 No recovery of A1; compound extinction increased A1’s extinction Results Response Rate Extinction Compound extinction Test (6 days later) Auditory 1 Light Auditory 2 Light & Auditory 1

  47. What is Learned in Extinction • S-O and R-O associations not eliminated • Current research suggests an inhibitory S-R association • Extinction effects will be highly specific to the context in which the response was extinguished • E.g., if you never got birthday presents on your birthday as a kid, you won’t be disappointed if you don’t get presents as an adult

  48. Rescorla (1993) • 1. Discrimination training (nose poke --> food) whenever Light or Noise present • 2. Lever press & chain pull (R1 & R2) --> food • No S-R association b/t L or N with R1 or R2 • 3. Extinction of N:R1 and L:R2 • Establishes inhibitory S-R associations • 4. Test • N: R1 vs. R2… more R2 responding • L: R1 vs. R2… more R1 responding • Can’t be due to S-O or R-O effects; has to be S-R

  49. S-R • Think back to our discussion of Central Emotional States • Decline in responding in extinction linked to frustration due to not getting what you expected • Leads to some seemingly odd effects

  50. Overtraining Extinction Effect • The more acquisition trials, the greater the expectancy of reward, hence the greater the frustration when extinction introduced • Produces more rapid extinction • Odd, because you’d expect that more training results in a stronger response that is more resistant to extinction

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