Download Chapter 5

Psychology: Brain, Mind,
and Culture, 2e
by
Drew Westen
Paul J. Wellman
Texas A&M University
John Wiley and Sons, Inc.
PowerPoint  Presentation: Chapter 5
Learning
Lecture Outline

Learning
 Classical Conditioning
• Acquisition
• Generalization versus discrimination
• Issues in classical conditioning
 Operant Conditioning
• Positive versus negative reinforcement
• Schedules of reinforcement
 Cognitive-social theory
• Expectancies and learning
© 1999 John Wiley and Sons, Inc.
Learning

Learning: Refers to an enduring change
in the way an organism responds based
on its experience
• Distinct from
– Drug effects (caffeine-iinduced jitters are not learning)
– Fatigue or illness

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
© 1999 John Wiley and Sons, Inc.
Classical Conditioning

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)
© 1999 John Wiley and Sons, Inc.
Pavlov’s Experiment
© 1999 John Wiley and Sons, Inc.
Conditioned Taste Aversion
 If a flavor is followed by an illness experience,
animals will not consume the flavor in the
future
CS
Taste
+
CS ----->
Flavor
UCS ----------> UCR
Toxic event
Nausea
CR
Nausea
© 1999 John Wiley and Sons, Inc.
Are These Examples of Classical
Conditioning?
 People smile to camera lights...
 A man listening to the radio feels a rush when
he hears a song that he and his fiance
listened to on a number of occasions...
 A cat runs into the kitchen when the can
opener is turning...
 A veteran dives to the street upon hearing a
car backfire...
 The smell of a steak produces salivation...
© 1999 John Wiley and Sons, Inc.
Stimulus
Generalization/Discrimination

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)
© 1999 John Wiley and Sons, Inc.
Hovland Results:
Stimulus Generalization
(Figure adapted from Hovland, 1937)
© 1999 John Wiley and Sons, Inc.
Acquisition and Extinction

Acquisition of classical conditioning:
• Requires pairing of CS and UCS

Extinction: Refers to the weakening of
conditioning evident when the CS is
presented repeatedly without the UCS (is
diminished but not lost)
 Spontaneous recovery: Refers to the
reemergence of a previously extinguished CR
© 1999 John Wiley and Sons, Inc.
Classical Conditioning Issues

Temporal order of CS and UCS is
important
• Best conditioning: CS precedes UCS (forward)
• Worst conditioning: UCS precedes CS
(backward)
© 1999 John Wiley and Sons, Inc.
Classical Conditioning Issues

Interstimulus Interval between CS and
UCS
• ISI’s longer than 2 sec produce poor conditioning

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
© 1999 John Wiley and Sons, Inc.
Biological Preparedness: The
Garcia Experiment
(Figure adapted from Garcia & Koelling, 1966)
© 1999 John Wiley and Sons, Inc.
Operant Conditioning

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

Operant conditioning and instrumental
conditioning: Responses operate on the
environment and are instrumental in
receiving reward
© 1999 John Wiley and Sons, Inc.
Are These Examples of Operant
Conditioning?
 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…
© 1999 John Wiley and Sons, Inc.
Positive Reinforcement

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
© 1999 John Wiley and Sons, Inc.
Issues in Negative Reinforcement

Negative reinforcement assumes that 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
© 1999 John Wiley and Sons, Inc.
Punishment

Punishment decreases the likelihood that
a response will occur
 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...
© 1999 John Wiley and Sons, Inc.
Difficulties in Punishment





Learner may not understand which operant
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 leads to future
aggression
© 1999 John Wiley and Sons, Inc.
Overview Of Conditioning
Schedules of Reinforcement

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
© 1999 John Wiley and Sons, Inc.
Impact of Schedules of
Reinforcement on Behavior
© 1999 John Wiley and Sons, Inc.
Scallop Pattern in Humans
(Figure adapted from Weisberg & Waldrop, 1972, p. 23)
© 1999 John Wiley and Sons, Inc.
Tolman’s Study on Latent Learning
(Figure adapted from Tolman & Honzik, 1930, p. 267)
© 1999 John Wiley and Sons, Inc.
Expectancies and Conditioning
 Cognitive-social theory argues that we form
expectancies about the consequences of our
behaviors
• These expectancies determine what is rewarding
 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
© 1999 John Wiley and Sons, Inc.
Locus of Control Scale
(Figure adapted from Rotter, 1971)
© 1999 John Wiley and Sons, Inc.
Copyright
Copyright 1999 by John Wiley and Sons, 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.
© 1999 John Wiley and Sons, Inc.