negative reinforcement - escape
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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. - PowerPoint PPT PresentationTRANSCRIPT
Negative Reinforcement - Escape
Negative reinforcement - Avoidance
Avoidance: Experimental Paradigm
The shuttle box
Light = CS
Light Shock
Shuttling stops shock
Two-Process Theory of Avoidance
Light Shock ( = Pavlovian Conditioning)
-Light elicits fear
Shuttling Reduction of Fear (= negative reinforcement)
Now, what happens with continued training?
Learned Helplessness Paradigm“Triadic” Design
Group A: Escapable Shock
Group B: Yoked Inescapable Shock
Group C: Exposure to apparatus only
Phase 1 Phase 2
Escape/Avoidance training
(For Group A shock can be terminated by rotating a wheel.)
Phase 2 Results
Inescapable shock
Inescapable shock
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
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.
LH in Humans
LH produced by…
insoluble logic problems
living in a crowded dorm
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.
Extinction
ExtinctionSession 1 Session 2 Session 3
Spontaneous recovery occurs as a function of time
8-day break
no breakno CS
Theories of Extinction
• Forgetting?
• Associative loss? (= “reverse acquisition”)
Extinction Associative Loss“Renewal”
Train Extinguish Test
Tone Shock
Context A
Context B
Tone -
Tone -
Tone: CRTone: CR
Bouton & King (1983)
In contrast, acquisition is not context-specific
Train Test
Tone Shock
Context A
Context B
Tone: CR
Tone: CR
Extinction Associative Loss“Reinstatement”
Train Extinguish Reinstatement Test
ToneShock Tone -Shock alone
--
Tone: CR
Tone: CR
Extinction Associative LossPost-extinction sensitivity to outcome devaluation
Rescorla 1996
So, what is learned in extinction?An inhibitory SR association?
S R
Context
Inhibitory SR 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?
Inhibitory SR Associations
• Summation test
• Retardation test
Does extinction produce them?
Train Ext Test
A+/B+ A- Test: AB
Train Ext Train
A+ A- AB+
Does A inhibit responding to B?
Does A inhibit acquisition to B?
So, what is learned in extinction?An inhibitory SR association?
S R
Context
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)
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.