Ch6_Learning
Learning Chapter 6 • Learning refers to a relatively durable change in behavior or knowledge that is due to experience • Conditioning involves learning associations between events that occur in an organism’s environment Classical Conditioning • Pavlov’s conditioning experiments –Salivary responses in dogs –Pairing of stimuli over time Elements of Classical Conditioning • Unconditioned Stimulus (UCS) • Unconditioned Response (UCR) • Conditioned Stimulus (CS) • Conditioned Response (CR) • Suzy goes outside to play in her tree house. A swarm of bees has nested near her tree house, and she gets stung when she climbs up to the tree house. This happens three times in a week. Suzy becomes afraid to go near the tree and cries violently when her dad tries to get her to climb up to the tree house. – – – – US UR CS CR bee sting, which causes pain escape from painful stimulus tree house avoidance of tree house • A couple goes to a movie on their first date and they have a wonderful time, eventually getting married. Whenever they see this movie on the late night show, they get a tender feeling and think about each other. – – – – US UR CS CR feelings for spouse love movie tender feeling, thinking of spouse • A student survives a plane crash that occurred because of a thunderstorm. Now, whenever the student hears thunder, he gets anxious. – US plane crash (caused by storm) – UR fear – CS thunderstorm – CR anxiety Establishing a Classically Conditioned Response • Repeated pairings, with close temporal spacing leads to establishing a response Classical Conditioning in Humans • Conditioned fear and anxiety – Phobias traced back to experiences involving classical conditioning • Bridge example – Everyday anxiety responses may also be products of classical conditioning • Dentist’s drill example Classical Conditioning UCS (passionate kiss) CS (onion breath) CS (onion breath) UCR (“butterflies”) UCS (passionate Kiss) CR (“butterflies”) UCR (sexual arousal) Classical Conditioning Strength of CR Acquisition (CS+UCS) Extinction (CS alone) Spontaneous recovery of CR Extinction (CS alone) Pause Nausea Conditioning in Cancer Patients UCS (drug) UCR (nausea) CS (waiting room) UCS (drug) UCR (nausea) CS (waiting room) CR (nausea) Classical Conditioning Operant Conditioning Elements of Operant Conditioning • Rats in a Skinner box: Speed of correct response increases over trials • Law of Effect = Principle of Reinforcement • Punishment does not equal Reinforcement A Closer Look at Reinforcement • Positive and Negative Reinforcement – Positive reinforces add something rewarding to the situation – Negative reinforcers remove an unpleasant stimulus • Continuous reinforcement • Intermittent (partial) reinforcement Schedules of Reinforcement • Fixed-Ratio: reinforcer given after a fixed # of nonreinforced responses – A student receives a gold star for every 5th correct answer • Variable-Ratio: reinforcer given after a variable # of nonreinforced responses – a slot machine pays out once every ten tries on the average • Fixed-Interval: reinforcer given for 1st response that occurs after a fixed time interval has elapsed – Checking the refrigerator to see if the JELL-O is ready • Variable-Interval: reinforcer is given for the 1st response after a variable time interval has elapsed. – A person refrains from drugs for fear of random drug testing Schedules of Reinforcement Number of responses 1000 Fixed Ratio Variable Ratio Fixed Interval 750 Rapid responding near time for reinforcement 500 Variable Interval 250 Steady responding 0 10 20 30 40 50 Time (minutes) 60 70 80 • Getting a pay check every other week – Fixed Interval • Pop Quizzes – Variable Interval • Slot machines at gambling casinos – Variable Ratio • A factory worker who is paid on piecework – Fixed Ratio • Watching for shooting stars – Variable Interval • Buying lottery tickets – Variable Ratio • Looking at your watch during a lecture until the end of lecture – Fixed Interval • Frequent flyer program: rewards after flying X amount of miles – Fixed Ratio • 1. Provide a word or term that means the same thing as negative reinforcement: 2. Negative reinforcement… • – – – • a. increases behavior. b. decreases behavior. c. has no effect on behavior. 3. If you were about to receive a negative reinforcement, would you look forward to it? – – • a. Yes b. No 4. Would you use positive reinforcement with a child? – – • a. Yes b. No 5. Would you use negative reinforcement with a child? – – a. Yes b. No A Closer Look at Punishment • Decreases the likelihood that ongoing behavior will recur • Should be swift, sufficient, certain • Generally not as effective as skillful application of reinforcement • Avoidance training is an alternative strategy (negative reinforcement) Behavioral Probability or Rate Action Increases Decreases Present Stimulus Positive Reinforcement Positive Punishment Remove Stimulus Negative Reinforcement Negative Punishment (Omission, timeout) Factors Shared by Classical and Operant Conditioning The Importance of Contingencies • Contingencies in classical conditioning – a reliable “if-then” relationship must be established between the CS and US • Contingencies in operant conditioning – Schedules of Reinforcement • Fixed interval, fixed-ratio, variable-interval, variable-ratio New Learning Based on Original Learning • Higher-order conditioning – An earlier CS becomes the US for further learning • Secondary reinforcers – Primary reinforcers: reinforcement rewarding in and of itself (food, water, warmth, affection) – Secondary reinforcers: value is learned through association ($, good grades, attention, flattery, praise, applause) Summing Up • Classical and Operant Conditioning both involve: –forming associations between stimuli and responses –perceiving contingencies between one event and another Summing Up • Main Difference is in CC the learner is passive and behavior is involuntary, whereas in OC, the learner is active and behavior involved is voluntary Biological constraints on learning • Instinctive drift – Innate response tendencies interfere with conditioning processes – Ex. Raccoons and coins • Conditioned taste aversion – Natural selection favors organisms that quickly learn what not to eat Learning by Observing • Social learning theory describes learning by watching – We are conditioned indirectly by observing others – Vicarious learning, reinforcement, punishment • Must have attention, retention, reproduction, and motivation for observational learning to be effective • Bandura’s study is a classic example-“BoBo dolls”
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