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LEARNING Chapter 8 Daisy, daisy, who shall it be? Who shall it be who will marry me? Rich man, poor man, beggarman, thief, Doctor, lawyer, merchant, chief, Tinker, tailor, soldier, sailor, Who shall it be who will marry me? (Old children’s nursery rhyme) What is NOT Learning? • Reflexes • Instincts • Imprinting (certain animals form attachments during a critical period early in life) Researched by Konrad Lorenz What is Learning? •Any relatively permanent change in behaviour potential that occurs because of experience •We learn by association •Conditioning - basic kind of learning Ivan Petrovich Pavlov, 1849-1936 • “What the hell difference does a revolution make. . .when you’ve got work to do in the lab?” • Classical or Pavlovian Conditioning Classical Conditioning •Studied digestion •Noticed salivation sec Components of Classical conditioning •Environmental conditioning of involuntary behaviour –Unconditioned stimulus (UCS, US) –Unconditioned response (UCR, UR) •unconditioned = unlearned –Conditioned stimulus (CS) –Conditioned response (CR) Processes of Conditioning •Acquisition •best learned when CS presented 1/2 sec prior to UCS Processes of Conditioning •Extinction Processes of Conditioning •Spontaneous Recovery How Long Does it Take? • John Garcia’s experiments found that it can take one instance • The Garcia effect: when you experience nausea after eating a food, that food becomes a CS to provoke nausea as a CR. The Study of Learning •Behaviourism –approach to psychology, U.S., 20th century –led by John Watson, carried further by B.F. Skinner –Emphasized observable behaviour, NOT the unconscious (like Freud). John Broadus Watson, 1878-1958 •1913 – He declared psychology a failure •“failed to establish itself as a natural science” •“should be a purely objective experimental branch of natural science” failur Environmental Determinism •“Give me a dozen healthy infants well formed and my own specified world to bring them up in and I’ll guarantee to take any one at random and train him to become any type of specialist I might select - doctor, lawyer, artist, merchant, chief, and yes, even beggarman and thief regardless of the talents, tendencies, abilities, vocations, and race of his ancestors.” –1925 Fear conditioning •Pairing of a NS with a fear-provoking object –very powerful –resistant to extinction –can occur after only 1 pairing –model for phobias –Little Albert (Watson/Rayner) Fear conditioning Generalization vs. Discrimination • Generalization: Responding to a similar stimulus • Discrimination: Responding ONLY to the exact stimulus Other applications Instrumental Conditioning •Edward Thorndike (1874-1949) – The Law of Effect “Behavior that is rewarded will be repeated” Burrhus Frederic Skinner, 1904-1990 Radical Behaviourism Operant Conditioning (Skinner) •Conditioning or learning of voluntary behaviors Operant Conditioning • Terminology – Reinforcement: a consequence that INCREASES the likelihood of the behavior – Punishment: a consequence that DECREASES the likelihood of the behavior Operant Conditioning Operant Conditioning •Negative Reinforcement: Two variations –Avoidant Behavior/Conditioning: behaving so that an unpleasant consequence is avoided—never starts –Escape Behavior/Conditioning: behaving so that an unpleasant consequence stops Schedules of Reinforcement •Continuous Reinforcement—consequence occurs for every target behavior •Partial or Intermittent Reinforcement— consequence does NOT occur for every behavior, but for some •*Actually better for getting desired behavior* Continuous vs Partial Reinforcement •Partial reinforcement –slower acquisition, but –MORE resistant to extinction –Skinner’s findings: –A pigeon on a schedule of continuous reinforcement may peck a key 50 to 100 times after reinforcement has been cut off –after some types of intermittent reinforcement, the bird will peck from 4000 to 10,000 times before responding extinguishes Continuous vs Partial Reinforcement • Partial Reinforcement Effect • -parents often learn this the hard way! – “I want candy.” “No.” “I want candy.” “No.” “I want candy.” “No.” “I want candy.” “Well, okay, just this once.” – The demanding has just been REINFORCED! Schedules of Reinforcement •Ratio = reinforcing according to the number of responses/behaviors •Interval = reinforcing according to time elapsed •Different combinations: •Fixed-Ratio (FR) getting paid by the piece •Variable-Ratio (VR) slot machines •Fixed-Interval (FI) candy on Fridays •Variable-Interval (VI) a realtor sells a house Reinforcers • Primary – Rewards that have biological or “natural” value (food) – Vs. – Secondary – Rewards that we must learn to value (money, approval from others) Reinforcers • Immediate: follow directly after the behavior (cookie for picking up toys) • Vs. • Delayed: a period of time passes (paychecks) Motivation • Skinner would object to discussing this: not observable! • Extrinsic Motivation – – – – For rewards that originate from outside vs. Intrinsic Motivation For rewards that bring personal satisfaction Motivation • Overjustification • When extrinsic rewards are emphasized too greatly, it can short circuit the development of intrinsic motivation Shaping •Rewarding successive approximations • • • • (“baby steps”) toward the overall desired behavior Biological Predispositions •Skinner underestimated importance of biology •Conditioning principles are constrained by biological predispositions of each species •(what animals can and can’t do, no matter how rewarding your reinforcement) •“Never try to teach a pig to sing. It wastes your time and annoys the pig.” Mark Twain Observational Learning Observational Learning •Bandura - Social Learning Theory –we learn by watching what others do and what happens to them for doing it –vicarious learning –vicarious reinforcement –vicarious punishment •Imitation: children tend to imitate adult models –classic Bobo doll study Observational Learning •people may learn anti-social behavior simply by observing it on tv