Outline. History of Learning Theory. Pavlov s Experiment: Step 1. Associative learning 9/26/2012. Nature or Nurture

Transcription

1 Outline What is learning? Associative Learning Classical Conditioning Operant Conditioning Observational Learning History of Learning Theory Nature or Nurture BEHAVIORISM Tabula Rasa Learning: Systematic, relatively permanent change in behavior as a result of Associative learning Learning about relationships between events Classical Conditioning Passive Reflexive behavior Pavlov s Experiment: Step 1 Natural Response: Unconditioned stimulus (UCS) automatically elicits the unconditioned response (UCR) Operant Conditioning Active participation of learner Consequences 1

2 Pavlov s Experiment: Step 2 Acquisition Phase: Repeatedly pair neutral stimulus with unconditioned stimulus (UCS) Pavlov s Experiment: Step 3 Successful Learning: Conditioned stimulus (CS) alone elicits the conditioned Classical Conditioning Acquisition A neutral stimulus elicits a reflexive response due to its association with a stimulus that naturally elicits the response Unconditioned = Reflex, automatic Conditioned = AFTER pairing of stimuli Example: The Office clip 2

3 Extinction Spontaneous Recovery Stimulus Discrimination Differentiating among stimuli Stimulus must be perceived as different Stimulus Generalization Stimuli similar to conditioned stimulus (CS) can elicit the conditioned response (CR) 3

4 Behaviorism Fear Conditioning John B. Watson ( ) Study of directly observable behaviors only Reflect psychological activity Explain all behavior through learning (experience) Little Albert Conducted by John B. Watson 1920 Fear Conditioning Sytematic Desensitization Little Albert Learned Response Rat Fear Step 1: Natural Response Step 2: Acquisition Rat (neutral) Loud Noise (UCS) + Loud Noise (UCS) Fear (UCR) Fear Automatic Response Rat + Meditation Loud Noise Relaxation Fear Step 3: Learned Response Rat (CS) Fear (CR) Rat + Meditation Relaxation Rat Relaxation Generalization: to all furry objects 4

5 Conditioned Taste Aversion (Seligman) Associative learning Classical Conditioning Process Only once is necessary May never become extinct Adaptive! Learning about relationships between events Classical Conditioning Passive Reflexive behavior Operant Conditioning Active participation of learner Consequences Thorndike s Puzzle Box B.F. Skinner: Operant Conditioning Instrumental Conditioning Law of Effect Stimulus Behavioral Response Consequence (box-string-freedom/food) Satisfying responses strengthened Discomforting responses weakened Behavioral Response Consequence (lever-food) Operant response Reinforcement 5

6 How do you get the response you want? Shaping Reinforce successive approximations Types of Consequences 1. Change in response rate Reinforcement: increase response Punishment: decrease response 2. Change in stimulus presence Positive: add stimulus Negative: subtract stimulus Types of Consequences Classes of Reinforcers Primary reinforcers Innately rewarding Secondary reinforcers Through classical conditioning Study Hard Get an A Brush cat Get bitten Break curfew Grounded (loss of privileges) Take Aspirin Remove headache 6

7 What makes an effective reinforcer? You must be hungry for the reinforcer e.g., If you have just eaten, you will no longer perform for food Immediate consequences are more effective than delayed consequences Contingent - a reinforcer that always follows the behavior Worth the effort - the reinforcer must be big enough to be worth the behavior Problems with Punishment Association with punisher Fear Learn not to get caught Ambiguity of punishment Does not teach appropriate behavior Aggression/Abuse Imitation What makes an effective punisher? Schedules of Reinforcement Apply immediately after unwanted behavior Apply consistently and only to unwanted behavior Greater than inherent reward of unwanted behavior Continuous reinforcement Reinforcement occurs after every response Partial reinforcement Intermittent Example: Only bring candy sometimes Followed by reinforcement of desired behavior 7

8 Partial Reinforcement Schedules Schedules and Response Patterns Acquisition and Extinction Classical vs. Operant Conditioning Continuous reinforcement schedules Easiest to acquire and extinguish Partial reinforcement schedules Hardest to extinguish Classical Reflexive Passive Inescapable for learner No motivation required Operant Consequences Active Learner must do something Motivation required 8

9 Operant Conditioning Gone Wrong Superstitious behavior Biological Preparedness and Classical Conditioning An evolutionary predisposition to form certain learned associations Learning thus far Cognitive Models of Learning Behaviorism Study directly observable behaviors only All behavior results from learning (environment!) Classical and Operant Conditioning But: Can we always see learning happening? Can we learn without reinforcement? How does thinking influence learning? Latent Learning Observational Learning Insight Learning 9

10 Latent Learning Observational Learning Learning that takes place in the absence of reinforcement: Practice makes perfect! Tolman (1948) Cognitive Maps: Mental representation of the physical features of the environment Learning by watching the actions of others Modeling other s behavior Social settings Kids are especially influenced Albert Bandura (1965) Bobo Doll study Video Bobo Doll Study Direct reinforcement not required Aggression and violence can be learned by watching others Imitation of specific acts Does watching violence on TV promote aggressive behavior? Possibly Study limitations: Correlation Causation Imitation of general intent but with novel acts Example: gun 10

11 Mirror Neurons Insight Learning Neurons active when an individual makes an action observes another performing the same action The Aha! experience Wolfgang Kohler (chimps) Basis for imitation learning Interpret behavior of others Study Strategies Classical conditioning Create or seek a positive environment or mood for studying Reinforcement schedules Regularly reinforce short bouts of studying Social learning Watch others demonstrate their knowledge in class or in study groups 11