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PSYCHOLOGY
Third Edition
by
Drew Westen
PowerPoint  Presentation
Chapter 5
LEARNING
John Wiley & Sons, Inc.
Lecture Outline
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Learning
Classical Conditioning
Operant Conditioning
Cognitive-social theory
© 2002 John Wiley & Sons, Inc.
Learning
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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
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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
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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
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Conditioned Taste Aversion
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If a flavor is followed by an illness
experience, animals will avoid the flavor in
the future
CS
Taste
+
CS ----->
Flavor
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UCS ----------> UCR
Toxic event
Nausea
CR
Nausea
Are These Examples of Classical
Conditioning?
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A man listening to the radio feels a rush when
he hears a song that was popular when he was
using cocaine...
A cat runs into the kitchen when the can opener
is turning...
A war veteran dives to the street upon hearing a
car backfire...
The smell of a steak produces salivation...
A student feels nauseated when entering a
classroom in which they earlier took a difficult
exam
© 2002 John Wiley & Sons, Inc.
Stimulus
Generalization/Discrimination
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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
Tone
+
UCS ----------> UCR
Shock
Pain
CS alone produced changes in GSR (associated with
anxiety)
© 2002 John Wiley & Sons, Inc.
Stimulus Generalization
Stimuli that are similar to the
training CS elicit similar
magnitude responses
(Figure adapted from Hovland, 1937)
© 2002 John Wiley & Sons, Inc.
Acquisition and Extinction
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Acquisition of classical
conditioning:
 Repeated pairings of CS and
UCS
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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
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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
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Interstimulus interval (ISI) between CS and UCS
is important for conditioning
• ISI’s longer than 2 sec produce poor conditioning
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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
Some associations are more easily learned than others
(Figure adapted from Garcia & Koelling, 1966)
© 2002 John Wiley & Sons, Inc.
Neural Bases of Classical
Conditioning
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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)
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Damage to the hippocampus impairs
contextual learning
© 2002 John Wiley & Sons, Inc
Operant Conditioning
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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
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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?
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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...
Drug addict injects heroin into a vein…
Rat presses a lever to obtain food…
Woman pays $42.00 for groceries…
Man turns off television that was blaring an MTV
video…
Student comes to class every day in order to take
notes…
© 2002 John Wiley & Sons, Inc.
Positive Reinforcement
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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
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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
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Punishment decreases the likelihood that a
response will occur
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
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Learner may not understand which operant
behavior is being punished
Learner may come to fear the teacher, rather
than learn an association between the action
and punishment (then avoids the teacher)
Punishment may not undo existing rewards
for a behavior
Using punishment when the teacher is angry
Punitive aggression may lead to future
aggression
© 2002 John Wiley & Sons, Inc.
Overview Of Conditioning
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Schedules of Reinforcement
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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
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Tolman’s Study on Latent Learning
(Figure adapted from Tolman & Honzik, 1930, p. 267)
© 2002 John Wiley & Sons, Inc.
Expectancies and Conditioning
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Cognitive-social theory argues that we form
expectancies about the consequences of our
behaviors
 These expectancies determine what is rewarding
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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)
© 2002 John Wiley & Sons, Inc.
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.