P S Y C H O L O G Y T h i r d E d i t i o n by Drew Westen PowerPoint  Presentation C h a p t e r 5 L E A R N I N G John Wiley & Sons, Inc.

Lecture Outline n Learning n Classical Conditioning n Operant Conditioning n Cognitive-social theory © 2002 John Wiley & Sons, Inc.

Learning n Learning refers to an enduring change in the way an organism responds based on its experience  Distinct from Drug effects (caffeine-induced jitters are not learning) Fatigue or illness n Three assumptions of learning theories  Responses are learned rather than innate  Learning is adaptive  Our experiments can uncover the laws of learning These laws will apply to animals and to humans © 2002 John Wiley & Sons, Inc.

Classical Conditioning n The Russian physiologist Pavlov noted that reflexive salivation in dogs could be elicited by stimuli associated with feeding  Reflex: Response that is reliably elicited by a stimulus Food elicits salivation Air puff elicits eye blink  Reflexive stimulus and response are unconditioned  Neutral stimulus is referred to as the conditioned stimulus (CS)  CS is paired with the UCS over many trials  Eventually comes to elicit a conditioned response (CR: resembles the UCR) © 2002 John Wiley & Sons, Inc.

Pavlov’s Experiment © 2002 John Wiley & Sons, Inc.

Conditioned Taste Aversion n If a flavor is followed by an illness experience, animals will avoid the flavor in the future CS + UCS > UCR Taste Toxic event Nausea CS -----> CR FlavorNausea © 2002 John Wiley & Sons, Inc.

Are These Examples of Classical Conditioning? n A man listening to the radio feels a rush when he hears a song that was popular when he was using cocaine... n A cat runs into the kitchen when the can opener is turning... n A war veteran dives to the street upon hearing a car backfire... n The smell of a steak produces salivation... n A student feels nauseated when entering a classroom in which they earlier took a difficult exam © 2002 John Wiley & Sons, Inc.

Stimulus Generalization/Discrimination n Generalization: If a response is conditioned to one stimulus, the organism may also respond to a similar stimulus, but not to a dissimilar stimulus (discrimination)  Hovland study: CS + UCS > UCR Tone Shock Pain CS alone produced changes in GSR (associated with anxiety) © 2002 John Wiley & Sons, Inc.

Stimulus Generalization © 2002 John Wiley & Sons, Inc. (Figure adapted from Hovland, 1937) Stimuli that are similar to the training CS elicit similar magnitude responses

Acquisition and Extinction n Acquisition of classical conditioning:  Repeated pairings of CS and UCS n Extinction: Refers to the weakening of conditioning evident when the CS is presented repeatedly without the UCS  Spontaneous recovery: Refers to the reemergence of a previously extinguished CR © 2002 John Wiley & Sons, Inc.

Classical Conditioning Issues n Temporal order of presentation of CS and UCS is important  Best conditioning: CS precedes UCS (forward)  Worst conditioning: UCS precedes CS (backward) © 2002 John Wiley & Sons, Inc.

Classical Conditioning Issues n Interstimulus interval (ISI) between CS and UCS is important for conditioning ISI’s longer than 2 sec produce poor conditioning n Prior conditioning history is important  Latent Inhibition: Repeated exposure to a neutral stimulus alone (no UCS) makes it more difficult to use the stimulus as a CS in the future Familiar ice cream taste is less likely to produce a CTA than a novel flavor  Blocking is the failure of a stimulus (light) to elicit a CR (salivation) when it is combined with a stimulus (bell) that already elicits the response (UCS is food) © 2002 John Wiley & Sons, Inc.

Biological Preparedness: The Garcia Experiment © 2002 John Wiley & Sons, Inc. (Figure adapted from Garcia & Koelling, 1966) Some associations are more easily learned than others

Neural Bases of Classical Conditioning n Stimuli produce changes in the nervous system which result in learning  Aplysia studies reveal changes in activity of individual neurons during learning  Bursts of electrical stimulation applied to the hippocampus of rats results in a tendency for these cells to fire more rapidly in the future (long-term potentiation) n Damage to the hippocampus impairs contextual learning © 2002 John Wiley & Sons, Inc

Operant Conditioning n Law of Effect: Behavior is controlled by its consequences  Thorndike experiment: Hungry cat learned to pull a string in order to leave a box and eat food from a bowl placed just outside the box n Operant conditioning and instrumental conditioning:  Responses operate on the environment and are instrumental in receiving reward © 2002 John Wiley & Sons, Inc.

Are These Examples of Operant Conditioning? n Woman inserts coins into a coke machine, presses the third button and receives five cans of soda. For the next week, she presses the third button on every coke machine she encounters... n Drug addict injects heroin into a vein… n Rat presses a lever to obtain food… n Woman pays $42.00 for groceries… n Man turns off television that was blaring an MTV video… n Student comes to class every day in order to take notes… © 2002 John Wiley & Sons, Inc.

Positive Reinforcement n Reinforcer: An environmental stimulus that occurs after the response and increases the likelihood that the response will occur in the future  Positive reinforcement: Process by which presentation of a stimulus after a response makes the response more likely to occur in the future  Negative reinforcement: Termination of an aversive event makes a behavior more likely to occur in the future © 2002 John Wiley & Sons, Inc.

Issues in Negative Reinforcement n Negative reinforcement involves a situation in which a response that terminates an aversive stimulus will strengthen that response  Taking an aspirin will reduce the headache and strengthen the behavior of aspirin-taking (sometimes referred to as escape-learning)  Avoidance learning: A response prevents a potentially aversive event from occurring Child cleans his room to avoid parental nagging © 2002 John Wiley & Sons, Inc.

Punishment n Punishment decreases the likelihood that a response will occur n Examples of punishing situations  Presentation of an aversive stimulus (Positive) Parent spanks a child for taking candy... Owner swats a dog who has chewed her slippers...  Removal of a reward (Negative) Teenager who stays out past curfew is not allowed to drive the family car for 2 weeks... Husband who forgets anniversary sleeps on couch for a week... © 2002 John Wiley & Sons, Inc.

Difficulties in Punishment n Learner may not understand which operant behavior is being punished n Learner may come to fear the teacher, rather than learn an association between the action and punishment (then avoids the teacher) n Punishment may not undo existing rewards for a behavior n Using punishment when the teacher is angry n Punitive aggression may lead to future aggression © 2002 John Wiley & Sons, Inc.

Overview Of Conditioning © 2002 John Wiley & Sons, Inc

Schedules of Reinforcement n Continuous reinforcement: Reinforcer is obtained for every response  Intermittent schedules: Reinforcer is not obtained for every response Ratio Schedules –Fixed Ratio: Every Nth response –Variable Ratio: The average is every Nth response Interval Schedules: –Fixed Interval: After the elapse of N minutes –Variable Interval: On average, after N minutes © 2002 John Wiley & Sons, Inc.

Impact of Schedules of Reinforcement on Behavior © 2002 John Wiley & Sons, Inc.

Tolman’s Study on Latent Learning © 2002 John Wiley & Sons, Inc. (Figure adapted from Tolman & Honzik, 1930, p. 267)

Expectancies and Conditioning n Cognitive-social theory argues that we form expectancies about the consequences of our behaviors  These expectancies determine what is rewarding n Locus of control: Refers to general expectancy as to whether fate does or not determine outcomes in life  Internal locus: Believe that their actions determine their fate  External locus: Believe that their lives are governed by forces outside their control © 2002 John Wiley & Sons, Inc.

Locus of Control Scale (Figure adapted from Rotter, 1971)

Copyright Copyright 2002 by John Wiley & Sons, Inc., New York, NY. All rights reserved. No part of the material protected by this copyright may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying, recording, or by any information storage and retrieval system, without written permission of the copyright owner. © 2002 John Wiley & Sons, Inc.