classical and instrumental conditioningjfkihlstrom/introductionweb...thorndike’s laws of learning...
TRANSCRIPT
1
Classical and InstrumentalConditioning
Lecture 8
2
Basic Procedure for Classical Conditioning
CS(Bell)
US(Meat Powder)
UR(Salivation)
CR(Salivation)
3
Major Phenomena ofClassical Conditioning
• Acquisition– CR to CS Reinforced by US– Response Gains Strength
• Magnitude of CR• Probability of CR
4
Acquisition: Trial 1
CS
US
CR
Bell
Food
Drops ofSaliva
Time
5
Acquisition: Trial 5
CS
US
CR
Bell
Food
Drops ofSaliva
Time
6
Acquisition: Trial 10
CS
US
CR
Bell
Food
Drops ofSaliva
Time
Acquisition of a Conditioned ResponseCS ==> US
0
0.2
0.4
0.6
0.8
1
1 2 3 4 5 6 7 8 9 10 11 12
Prob
abili
ty o
f CR
Trials
Negative Acceleration
Positive Acceleration
The “Sigmoidal” (S-Shaped) Learning Curve is Also Known as an Ogive
7
Two Shapes to the Learning Curve
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
Res
pons
e S
treng
th
Trials
Naïve Organism/Complex Behavior
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
Res
pons
e S
treng
th
Trials
Experienced Organism/Simple Behavior
8
9
Major Phenomena ofClassical Conditioning
• Acquisition• Extinction
– No Reinforcement– Response Loses Strength
10
Extinction: Trial 1
CS
US
CR
Bell
Food
Drops ofSaliva
Time
11
Extinction: Trial 5
CS
US
CR
Bell
Food
Drops ofSaliva
Time
12
Extinction: Trial 10
CS
US
CR
Bell
Food
Drops ofSaliva
Time
13
Extinction of a Conditioned ResponseCS ==> No US
0
0.2
0.4
0.6
0.8
1
1 2 3 4 5 6 7 8 9 10 11 12
Prob
abili
ty o
f CR
Trials
14
Major Phenomena ofClassical Conditioning
• Acquisition• Extinction• Spontaneous Recovery
– Rest After Extinction– Retest CS alone
15
Spontaneous Recovery After ExtinctionCS ==> No US
0
0.2
0.4
0.6
0.8
1
Prob
abili
ty o
f CR
Trials
Acquisition Extinction
SpontaneousRecovery
(Rest)
FurtherExtinction
16
Re-Acquisition of Extinguished ResponseCS ==> US
0
0.2
0.4
0.6
0.8
1
Prob
abili
ty o
f CR
Trials
Acquisition Extinction Re-Acquisition
SpontaneousRecovery
Savings inRelearning
(Rest)
17
Extinction Below Zero
• Extinction Trials Continued After CR Disappears Entirely
• Reduced Spontaneous Recovery• Less Savings in Relearning
– Slower Reacquisition
18
Major Phenomena ofClassical Conditioning
• Acquisition• Extinction
– Extinction Below Zero• Spontaneous Recovery• Re-Acquisition
– CS Reinforced by US– Savings in Relearning
19
Implications of Savingsand Spontaneous Recovery
• Conditioned Response Not “Lost”• Rather, Inhibited or Suppressed
– In Line with Changing Circumstances• Conditioned Stimulus No Longer Reinforced
• CR Can be Disinhibited– In Line with Changing Circumstances
• CS Reinforced Once Again
20
Major Phenomena ofClassical Conditioning
• Acquisition• Extinction• Spontaneous Recovery• Re-Acquisition• Generalization
– CS0 vs. CS1…CSn
– Generalization Gradient
21
The Generalization Gradient
00.10.20.30.40.50.60.70.80.9
1
-5 -4 -3 -2 -1 0 1 2 3 4 5
Prob
abili
ty o
f CR
Test Stimulus
OriginalCS
Lower Higher
250cps
200cps 300cps
350cps150cps
22
Major Phenomena ofClassical Conditioning
• Acquisition• Extinction• Spontaneous Recovery• Re-Acquisition• Generalization• Discrimination
– CS+ (Reinforced)– CS- (Unreinforced)
23
Discrimination LearningCS+ ==> US
CS- ==> No US
0
0.2
0.4
0.6
0.8
1
1 2 3 4 5 6 7 8 9 10 11 12
Prob
abili
ty o
f CR
Trials
CS+CS-
250 cps
200 cps
24
Review of Classical Conditioning
• Vocabulary– Unconditioned Stimulus– Unconditioned Response– Conditioned Stimulus– Conditioned Response
• Phenomena– Acquisition
• Reinforcement– Extinction– Spontaneous Recovery– Savings in Relearning– Generalization
• Generalization Gradient– Discrimination
25
Sensory Preconditioning
CS2
US
CR
Bell
Food
Saliva
Light
CS2
CS1
Bell
Saliva
LightCS1
CR
1
2
3
26
Higher-Order Conditioning
CS1
US
CR
Bell
Food
Saliva
Light
CS1
CS2
Bell
Saliva
LightCS2
CR
1
2
3
27
Significance of Classical Conditioning
• Extends Control of Reflexes to Other Environmental Events– Associations between Events
• Ubiquitous (Nervous System)• Pavlov: All Learning is Classical
Conditioning (?)• Laws of Classical Conditioning are the
Laws of Emotional Life
28
Thorndike’s Puzzle Box
29
Thorndike’s Results
30
Thorndike’s Laws of Learning
Law of Readiness
Law of Effect
Law of Exercise
31
Instrumental Conditioning(Operant Conditioning)
• Learn Adaptive Behavior– Through Experience of Success, Failure
• Organism Operates on Environment– Behavior Changes Environment
• Behavior Instrumental– Obtains Desired State of Affairs
• Associations between Behaviors and Outcomes
32
B.F. Skinner’s Operant Chamber
33
Instrumental Conditioning Procedure
• Phase 1: Baseline Behavior• Phase 2: Acquisition Phase• Phase 3: Discrimination Learning• Phase 4: Extinction
34
Vocabulary of Instrumental Conditioning
• Conditioned Response (No URs)• Conditioned Stimulus (No USs)• Reinforcement
– Positive– Negative (Not Punishment)
• Acquisition• Extinction• Generalization• Discrimination
35
Schedules of Reinforcement• Continuous• Partial• Intermittent
– Fixed Ratio (FR)– Variable Ratio (VR)– Fixed Interval (FI)– Variable Interval (VI)
• Differential Reinforcement– Of Low Rates (DRL)– Of High Rates (DRH)
36
Intermittent Reinforcement
The Matching LawHerrnstein (1970)
• Concurrent VI Schedules– Give Organism a Choice
• Key A: VI3 • Key B: VI1
• Response Rate is Proportional to the Frequency of Reinforcement– Also Magnitude, Delay of Reinforcement
• Basic Principle of Microeconomics– Supply and Demand
• Relative Value of Reinforcers 37
38
Significance of Instrumental Conditioning
• Voluntary Behaviors Come Under Control of Environmental Events– Behavior-Outcome Associations
• Ubiquitous (Vertebrates)• Thorndike, Skinner: All Learning is
Instrumental/Operant Conditioning (?)• Laws of Instrumental Conditioning Are
the Laws of Adaptive Behavior– Habits– Incentives