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Negative Reinforcement - Escape

Negative Reinforcement - Escape. Negative reinforcement - Avoidance. Avoidance: Experimental Paradigm. Light = CS. Light  Shock. Shuttling stops shock. The shuttle box. Two-Process Theory of Avoidance. Light  Shock ( = Pavlovian Conditioning). -Light elicits fear.

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Negative Reinforcement - Escape

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  1. Negative Reinforcement - Escape

  2. Negative reinforcement - Avoidance

  3. Avoidance: Experimental Paradigm Light = CS Light  Shock Shuttling stops shock The shuttle box

  4. Two-Process Theory of Avoidance Light  Shock ( = Pavlovian Conditioning) -Light elicits fear Shuttling  Reduction of Fear (= negative reinforcement) Now, what happens with continued training?

  5. Learned Helplessness Paradigm “Triadic” Design Phase 1 Phase 2 Group A: Escapable Shock Group B: Yoked Inescapable Shock Group C: Exposure to apparatus only Escape/Avoidance training (For Group A shock can be terminated by rotating a wheel.)

  6. Phase 2 Results Inescapable shock Inescapable shock

  7. Possible Explanations • Learned Helplessness: Organisms learn that their behavior is ineffectual • Poverty of activity: inescapable shock reduces the variability in behavior that is so crucial for operant conditioning • Inattention: animals stop attending to their own behavior

  8. LH in the Spinal Cord • Recall: many reflexes are mediated within the spinal cord. • Operant conditioning can occur within SC (escape/avoidance of leg shock after SC transection) • Grau: Experience with inescapable legshock will prevent subsequent avoidance learning.

  9. LH in Humans LH produced by… insoluble logic problems living in a crowded dorm

  10. LH in the Spinal Cord • Recall: many reflexes are mediated within the spinal cord. • Operant conditioning can occur within SC (escape/avoidance of leg shock after SC transection) • Grau: Experience with inescapable legshock will prevent subsequent avoidance learning.

  11. Extinction

  12. Extinction Session 1 Session 2 Session 3

  13. 8-day break no break no CS Spontaneous recovery occurs as a function of time

  14. Theories of Extinction • Forgetting? • Associative loss? (= “reverse acquisition”)

  15. Extinction  Associative Loss “Renewal” Train Extinguish Test Tone: CR Tone - Tone  Shock Tone: CR Tone - Context A Context B Bouton & King (1983)

  16. In contrast, acquisition is not context-specific Train Test Tone: CR Tone  Shock Tone: CR Context A Context B

  17. Extinction  Associative Loss “Reinstatement” Train Extinguish Reinstatement Test Tone: CR Shock alone ToneShock Tone - -- Tone: CR

  18. Extinction  Associative Loss Post-extinction sensitivity to outcome devaluation Rescorla 1996

  19. Context S R So, what is learned in extinction? An inhibitory SR association?

  20. Inhibitory SR Associations Theory • In extinction, the context effectively becomes a conditioned inhibitor. • Why? Just like in normal CI, there is the violation of expectations of reinforcement • But is this true?

  21. Inhibitory SR Associations Does extinction produce them? • Summation test • Retardation test Train Ext Test A+/B+ A- Test: AB Does A inhibit responding to B? Train Ext Train A+ A- AB+ Does A inhibit acquisition to B?

  22. Context S R So, what is learned in extinction? An inhibitory SR association?

  23. Paradoxical Effects of Reward • Overtraining extinction effect: more training leads to faster extinction • Reinforcement magnitude effect: Big rewards lead to faster extinction • And, of course, the partial reinforcement extinction effect (PREE)

  24. Paradoxical effects of reward: Why? • Frustration hypothesis (Amsel): animals learn to make response as a reaction to nonreward. • Discrimination hypothesis: Nonreinforcement is easier to detect after CRF than PRF. • Sequential theory (Capaldi): The memory of nonreinforcement becomes a cue that elicits responding.

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