1 / 58

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

fauna
Télécharger la présentation

Extinction of Conditioned Behaviour

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  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

More Related