Classical and Instrumental Conditioning
Lecture 8
1 Basic Procedure for Classical Conditioning
CS US (Bell) (Meat Powder)
CR UR (Salivation) (Salivation)
2 Major Phenomena of Classical Conditioning • Acquisition – CR to CS Reinforced by US – Response Gains Strength • Magnitude of CR • Probability of CR
3 Acquisition: Trial 1
CS Bell
Food US Drops of CR Saliva
Time
4 Acquisition: Trial 5
CS Bell
Food US Drops of CR Saliva
Time
5 Acquisition: Trial 10
CS Bell
Food US Drops of CR Saliva
Time
6 Acquisition of a Conditioned Response CS ==> US
1
0.8 Positive 0.6 Acceleration Negative Acceleration 0.4
Probability Probability of CR 0.2 The “Sigmoidal” (S-Shaped) Learning Curve is Also Known as an Ogive 0 1 2 3 4 5 6 7 8 9 10 11 12
Trials
7 Two Shapes to the Learning Curve
Naïve Organism/ Experienced Organism/ Complex Behavior Simple Behavior Response Strength Response Strength
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Trials Trials
8 Major Phenomena of Classical Conditioning • Acquisition • Extinction – No Reinforcement – Response Loses Strength
9 Extinction: Trial 1
CS Bell
Food US Drops of CR Saliva
Time
10 Extinction: Trial 5
CS Bell
Food US Drops of CR Saliva
Time
11 Extinction: Trial 10
CS Bell
Food US Drops of CR Saliva
Time
12 Extinction of a Conditioned Response CS ==> No US 1
0.8
0.6
0.4
Probability Probability of CR 0.2
0 1 2 3 4 5 6 7 8 9 10 11 12
Trials
13 Major Phenomena of Classical Conditioning • Acquisition • Extinction • Spontaneous Recovery – Rest After Extinction – Retest CS alone
14 Spontaneous Recovery After Extinction CS ==> No US
Acquisition Extinction 1
0.8 Spontaneous 0.6 Recovery
0.4 Further Probability CR of Probability Extinction 0.2 (Rest) 0
Trials 15 Re-Acquisition of Extinguished Response CS ==> US
Acquisition Extinction Re-Acquisition 1
0.8 Savings in Relearning 0.6
0.4 Spontaneous
Probability of CR Recovery 0.2 (Rest) 0
Trials
16 Extinction Below Zero
• Extinction Trials Continued After CR Disappears Entirely • Reduced Spontaneous Recovery • Less Savings in Relearning – Slower Reacquisition
17 Major Phenomena of Classical Conditioning • Acquisition • Extinction – Extinction Below Zero • Spontaneous Recovery • Re-Acquisition – CS Reinforced by US – Savings in Relearning
18 Implications of Savings and 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
19 Major Phenomena of Classical Conditioning • Acquisition • Extinction • Spontaneous Recovery • Re-Acquisition • Generalization
– CS0 vs. CS1…CSn – Generalization Gradient
20 The Generalization Gradient
250cps 1 0.9 0.8 200cps 300cps 0.7 Lower 0.6 Higher 0.5 0.4 150cps Original 350cps 0.3 CS Probability Probability of CR 0.2 0.1 0 -5 -4 -3 -2 -1 0 1 2 3 4 5
Test Stimulus
21 Major Phenomena of Classical Conditioning • Acquisition • Extinction • Spontaneous Recovery • Re-Acquisition • Generalization • Discrimination – CS+ (Reinforced) – CS- (Unreinforced)
22 Discrimination Learning CS+ ==> US CS- ==> No US
1 250 cps 0.8
0.6 CS+
0.4 CS- 200 cps Probability Probability of CR 0.2
0 1 2 3 4 5 6 7 8 9 10 11 12
Trials
23 Review of Classical Conditioning
• Vocabulary • Phenomena – Unconditioned Stimulus – Acquisition – Unconditioned Response • Reinforcement – Conditioned Stimulus – Extinction – Conditioned Response – Spontaneous Recovery – Savings in Relearning – Generalization • Generalization Gradient – Discrimination
24 Sensory Preconditioning
CS1 Light 1 CS2 Bell
CS2 Bell 2 US Food CR Saliva
CS1 Light 3 CR Saliva25 Higher-Order Conditioning
CS1 Bell 1 US Food CR Saliva
CS2 Light 2 CS1 Bell
CS2 Light 3 CR Saliva26 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
27 Thorndike’s Puzzle Box
28 Thorndike’s Results
29 Thorndike’s Laws of Learning
Law of Readiness
Law of Effect
Law of Exercise
30 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
31 B.F. Skinner’s Operant Chamber
32 Instrumental Conditioning Procedure
• Phase 1: Baseline Behavior • Phase 2: Acquisition Phase • Phase 3: Discrimination Learning • Phase 4: Extinction
33 Vocabulary of Instrumental Conditioning
• Conditioned Response (No URs) • Conditioned Stimulus (No USs) • Reinforcement – Positive – Negative (Not Punishment) • Acquisition • Extinction • Generalization
• Discrimination 34 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) 35 Intermittent Reinforcement
36 The Matching Law Herrnstein (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 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 38