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Learning

Learning
 relatively
permanent
change in an
organism’s
behavior due
to experience
1
How Do We Learn?
We learn by association. Our minds
naturally connect events that occur in
sequence.
2000 years ago, Aristotle suggested this law
of association. Then 200 years ago Locke
and Hume reiterated this law.
2
Association
 We learn by association
 Our minds naturally connect events that occur
in sequence
 Aristotle 2000 years ago
 John Locke and David Hume 200 years ago
 Associative Learning
 learning that two events occur together
 two stimuli
 a response and its consequences
3
Association
Event 1
Event 2
 Learning to
associate
two events
Sea snail associates splash with a tail shock
Seal learns to expect a snack for its showy antics
4
Classical or Pavlovian
Conditioning
 We learn
to
associate
two stimuli
5
Operant Conditioning
 We learn to
associate a
response and
its
consequence
6
Classical Conditioning
 Classical Conditioning
 organism comes to associate two
stimuli
 a neutral stimulus that signals an
unconditioned stimulus begins to
produce a response that anticipates and
prepares for the unconditioned stimulus
7
Classical Conditioning
Sovfoto
Ideas of classical conditioning originate from old
philosophical theories. However, it was the Russian
physiologist Ivan Pavlov who elucidated classical
conditioning. His work provided a basis for later
behaviorists like John Watson and B. F. Skinner.
Ivan Pavlov (1849-1936)
8
Ivan Pavlov
 Classical conditioning
 Experiments on dogs
9
Classical Conditioning and
Pavlov’s Dogs: Hypothesis
• Dogs salivate when
food is placed in their
mouths
• Dogs salivate at mere
sight of food
• Hypothesis: Dogs can
be trained, or
conditioned, to salivate
when exposed to an
external stimulus
10
Pavlov’s Experiments
Before conditioning, food (Unconditioned
Stimulus, US) produces salivation (Unconditioned
Response, UR). However, the tone (neutral
stimulus) does not.
11
Pavlov’s Experiments
During conditioning, the neutral stimulus (tone)
and the US (food) are paired, resulting in
salivation (UR). After conditioning, the neutral
stimulus (now Conditioned Stimulus, CS) elicits
salivation (now Conditioned Response, CR)
12
Pavlov’s Methodology
and Results
 Harness dog and
place tube to
collect saliva
 Present external
stimulus (bell)
immediately before
giving food
 Results: After a few
trials, the dog
salivates upon
hearing the bell
 Works with other
stimuli as well
13
Pavlov’s Conclusions
Unconditioned Unconditioned
Stimulus
Response
(UCS)
(UCR)
because of
Conditioned
Response
(CR)
Conditioned
Stimulus
(CS)
because of
14
Pavlov’s Classic Experiment
Before Conditioning
UCS (food
in mouth)
UCR
(salivation)
During Conditioning
Neutral
stimulus
(tone)
No
salivation
After Conditioning
UCS (food
in mouth)
Neutral
stimulus
(tone)
UCR
(salivation)
CS
(tone)
CR (salivation)
15
16
Classical Conditioning
NEUTRAL STIMULUS
will
elicit
NO REACTION
UNCONDITIONED STIMULUS
will
elicit a
REFLEX ACTION
will
elicit a
REFLEX ACTION
will
elicit a
CONDITIONED
RESPONSE17
UNCONDITIONED STIMULUS
NEUTRAL STIMULUS
CONDITIONED
CONDITIONEDSTIMULUS
STIMULUS
18
Classical Conditioning
 Unconditioned Stimulus (UCS)
 stimulus that unconditionally--automatically
and naturally--triggers a response
 Unconditioned Response (UCR)
 unlearned, naturally occurring response to the
unconditioned stimulus
 salivation when food is in the mouth
19
Classical
Conditioning
 Conditioned Stimulus (CS)
 originally irrelevant stimulus that, after
association with an unconditioned stimulus,
comes to trigger a conditioned response
 Conditioned Response (CR)
 learned response to a previously neutral
conditioned stimulus
20
21
22
Continuing Pavlov’s
Experiment
Other Aspects of Classical Conditioning
 Acquisition
 Extinction
 Spontaneous Recovery
 Generalization
 Discrimination
23
Classical Conditioning
 Acquisition
 the initial stage in classical conditioning
 the phase associating a neutral stimulus with
an unconditioned stimulus so that the neutral
stimulus comes to elicit a conditioned
response
 in operant conditioning, the strengthening of a
reinforced response
24
Acquisition
Acquisition is the initial stage in classical
conditioning in which an association between a
neutral stimulus and an unconditioned stimulus
takes place.
1. In most cases, for conditioning to occur, the
neutral stimulus needs to come before the
unconditioned stimulus.
2. The time in between the two stimuli should
be about half a second.
25
Acquisition
The CS needs to come half a second before
the US for acquisition to occur.
26
Classical Conditioning
 Extinction
 diminishing of a CR
 in classical conditioning, when a
UCS does not follow a CS
 in operant conditioning, when a
response is no longer reinforced
27
Extinction
When the US (food) does not follow the CS
(tone), CR (salivation) begins to decrease and
eventually causes extinction.
28
Spontaneous Recovery
After a rest period, an extinguished CR (salivation)
spontaneously recovers, but if the CS (tone) persists
alone, the CR becomes extinct again.
29
Stimulus Generalization
Tendency to respond to
stimuli similar to the CS is
called generalization. Pavlov
conditioned the dog’s
salivation (CR) by using
miniature vibrators (CS) on
the thigh. When he
subsequently stimulated
other parts of the dog’s
body, salivation dropped.
30
Stimulus Discrimination
Discrimination is the learned ability to distinguish
between a conditioned stimulus and other stimuli that
do not signal an unconditioned stimulus.
31
Extending Pavlov’s Understanding
Pavlov and Watson considered consciousness,
or mind, unfit for the scientific study of
psychology. However, they underestimated the
importance of cognitive processes and
biological constraints.
32
Cognitive Processes
Early behaviorists believed that learned
behaviors of various animals could be reduced
to mindless mechanisms.
However, later behaviorists suggested that
animals learn the predictability of a stimulus,
meaning they learn expectancy or awareness
of a stimulus (Rescorla, 1988).
33
Biological Predispositions
Pavlov and Watson believed that laws of
learning were similar for all animals. Therefore,
a pigeon and a person do not differ in their
learning.
However, behaviorists later suggested that
learning is constrained by an animal’s biology.
34
Biological Predispositions
Courtesy of John Garcia
Garcia showed that the duration
between the CS and the US may be
long (hours), but yet result in
conditioning. A biologically adaptive
CS (taste) led to conditioning and not
to others (light or sound).
John Garcia
35
Biological Predispositions
John Garcia
Conditioned taste aversions
 Not all neutral stimuli can become
conditioned stimuli.
 Internal stimuli—associate better with taste
 External stimuli—associate better with pain
 Biological preparedness

36
Cognitive Processes
Conditioning occurs best when the CS and
UCS have just the sort of relationship that
would lead a scientist to conclude that the
CS causes the UCS. — even in classical
conditioning, it is not only the simple
stimulus-response association but also the
thought that counts.
 Conditioning in advertising
37
Nausea Conditioning in Cancer Patients
UCS
(drug)
UCR
(nausea)
CS
(waiting
room)
UCS
(drug)
UCR
(nausea)
CS
(waiting
room)
CR
(nausea)
38
Pavlov’s Legacy
Pavlov’s greatest contribution
to psychology is isolating
elementary behaviors from
more complex ones through
objective scientific
procedures.
Ivan Pavlov
(1849-1936)
39
Applications of Classical Conditioning
Brown Brothers
Watson used classical
conditioning procedures to
develop advertising
campaigns for a number of
organizations, including
Maxwell House, making the
“coffee break” an American
custom.
John B. Watson
40
Applications of Classical Conditioning
1.
2.
Alcoholics may be conditioned (aversively)
by reversing their positive-associations with
alcohol.
Through classical conditioning, a drug (plus
its taste) that affects the immune response
may cause the taste of the drug to invoke
the immune response.
41
Operant & Classical Conditioning
1. Classical conditioning
forms associations
between stimuli (CS
and US). Operant
conditioning, on the
other hand, forms an
association between
behaviors and the
resulting events.
42
Operant & Classical Conditioning
2.
Classical conditioning involves respondent
behavior that occurs as an automatic
response to a certain stimulus. Operant
conditioning involves operant behavior, a
behavior that operates on the environment,
producing rewarding or punishing stimuli.
43
Behaviorism
 John B. Watson
 viewed psychology as
objective science
 generally agreed-upon
consensus today
 recommended study of
behavior without reference
to unobservable mental
processes
 not universally accepted by all
schools of thought today
44
John Watson and Rosalie Rayner:
Hypothesis, Methodology, Results
 Conditioned fear into
an infant
 Presented a rat
immediately followed
by a loud noise,
startling the baby
 After a few tries,
Albert was afraid of
the rat
 Albert generalized his
fears to other furry
objects
+
=
45
Watson took a a baby named Albert and conditioned him to be
afraid of white furry objects using Pavlov’s techniques.
Watson & Raynor with Little Albert
46
47
Conditional Training:
Albert and Peter
Conditioned fear
experiments such as
Albert’s experience
would never occur
today because of the
existing ethical
standards.
48
Mary Cover Jones
• In 1925, Mary Cover Jones (a colleague of Watson) hypothesized
that she would be able to decondition a three-year-old boy named
Peter from some of his fears, which included feathers, cotton, frogs,
fish, rats, rabbits, and mechanical toys. She began by bringing a
caged rabbit into the same room where Peter was having a snack in
his highchair. The rabbit was far enough away that it did not bother
Peter. The next day, she brought the rabbit increasingly closer to
Peter until he began to become disturbed. On subsequent days, the
rabbit was moved closer and closer to Peter’s highchair only to the
point at which Peter became afraid, at which time they’d end the
experiment for the day. Eventually, Peter was able to pet the rabbit,
having been deconditioned from his fear. Jones was able to
decondition most of Peter’s other fears in this manner.
• Watson and Rayner’s experiment with Little Albert showed that
people can be conditioned to fear specific types of objects.
Conversely, Jones suggested that people could be deconditioned
from their fears. Similar methods are used today to help people
overcome phobias.
49
Mary Cover Jones
Mary Cover Jones used an
early form of desensitization
to prove that fears (phobias)
could be unlearned.
Peter, a young boy, had an extreme
fear of rabbits. Jones gave Peter his
favorite food while slowly bringing the
rabbit closer and closer. Eventually
Peter no longer panicked around
rabbits.
50
Mary Cover Jones
• Colleague of Watson
• Deconditioned 3-year-old Peter from his fears by
gradually moving a rabbit (and other things) closer to
him while he was eating
DAY 1
DAY 2
DAY 3
51
Operant Conditioning
 Operant Conditioning
 type of learning in which behavior is
strengthened if followed by reinforcement or
diminished if followed by punishment
 Law of Effect
 Thorndike’s principle that behaviors followed
by favorable consequences become more
likely, and behaviors followed by unfavorable
consequences become less likely
52
Operant Conditioning
 Operant Behavior
 operates (acts) on environment
 produces consequences
 Respondent Behavior
 occurs as an automatic response to
stimulus
 behavior learned through classical
conditioning
53
Early Operant Conditioning
E. L. Thorndike (1898)
Puzzle boxes and cats
First Trial
Scratch at bars
After Many
Scratch at bars
in Box
Push at ceiling
Trials in Box
Push at ceiling
Situation:
stimuli
inside of
puzzle box
Dig at floor
Howl
Etc.
Situation:
stimuli
inside of
puzzle box
Dig at floor
Howl
Etc.
Etc.
Etc.
Press lever
Press lever
54
Edward L. Thorndike ( 1874–1949)
55
Skinner’s Experiments
Skinner’s experiments extend Thorndike’s
thinking, especially his law of effect. This law
states that rewarded behavior is likely to occur
again.
Yale University Library
56
Using Thorndike's law of effect as a starting
point, Skinner developed the Operant chamber,
or the Skinner box, to study operant
conditioning.
Walter Dawn/ Photo Researchers, Inc.
From The Essentials of Conditioning and Learning, 3rd
Edition by Michael P. Domjan, 2005. Used with permission
by Thomson Learning, Wadsworth Division
Operant Chamber
57
B.F. Skinner
and Operant
Conditioning


Classical conditioning involves an automatic
response to a stimulus
Operant conditioning involves learning how to control
one’s response to elicit a reward or avoid a
punishment
58
Operant Conditioning
 B.F. Skinner
(1904-1990)
 elaborated
Thorndike’s Law
of Effect
 developed
behavioral
technology
59
B. F. Skinner (1904–1990)
60
The “Skinner Box”: Skinner’s
Hypothesis, Methodology, and
Results




Rats placed in
“Skinner boxes”
Shaped to get
closer and closer to
the bar in order to
receive food
Eventually required
to press the bar to
receive food
Food is a reinforcer
61
Operant Chamber
The operant chamber,
or Skinner box, comes
with a bar or key that
an animal manipulates
to obtain a reinforcer
like food or water. The
bar or key is connected
to devices that record
the animal’s response.
62
Shaping
Shaping is the operant conditioning procedure in
which reinforcers guide behavior towards the
desired target behavior through successive
approximations.
Fred Bavendam/ Peter Arnold, Inc.
Khamis Ramadhan/ Panapress/ Getty Images
A rat shaped to sniff mines. A manatee shaped to discriminate
objects of different shapes, colors and sizes.
63
64
p. 228
65
p. 228
Types of Reinforcers
Any event that strengthens the behavior it
follows. A heat lamp positively reinforces a
meerkat’s behavior in the cold.
Reuters/ Corbis
66
Operant Conditioning
 Positive Reinforcement
 any event that
strengthens the
behavior it follows
 Negative Reinforcement
 The removal of a punishment or an
aversive stimulus
 It STRENGTHENS behavior
67
Negative Reinforcement
and Punishment
Negative reinforcement:
Removing an unpleasant
stimulus
1. Unpleasant stimulus
Punishment
1. Introducing
an unpleasant
stimulus
=
2. Removal of unpleasant stimulus
2. Withholding
a pleasant
stimulus
=
68
69
Figure 6.18 Positive reinforcement versus negative reinforcement
70
Figure 6.20 Comparison of negative reinforcement and punishment
71
Operant Conditioning
72
73
74
Primary & Secondary Reinforcers
1. Primary Reinforcer: An innately reinforcing
stimulus like food or drink.
2. Conditioned Reinforcer (secondary
reinforcer): A learned reinforcer that gets its
reinforcing power through association with
the primary reinforcer.
75
Immediate & Delayed Reinforcers
1. Immediate Reinforcer: A reinforcer that
occurs instantly after a behavior. A rat gets
a food pellet for a bar press.
2. Delayed Reinforcer: A reinforcer that is
delayed in time for a certain behavior. A
paycheck that comes at the end of a week.
We may be inclined to engage in small immediate
reinforcers (watching TV) rather than large delayed
reinforcers (getting an A in a course) which require
consistent study.
76
Reinforcement Schedules
1. Continuous Reinforcement: Reinforces the
desired response each time it occurs.
2. Partial Reinforcement: Reinforces a
response only part of the time. Though this
results in slower acquisition in the
beginning, it shows greater resistance to
extinction later on.
77
Rates and Types of
Reinforcement:
Additional Experiments
Fixed-ratio: food given after a fixed number
of responses
Variable-ratio: number of responses
required to get food changes each time
Fixed-interval: food given after a certain
amount of time elapses
Variable-interval: amount of time
required to get food changes each time
78
Schedules of Reinforcement
 Fixed Ratio (FR)
 reinforces a response only after a
specified number of responses
 faster you respond the more rewards you
get
 different ratios
 very high rate of responding
 like piecework pay
79
Schedules of Reinforcement
 Variable Ratio (VR)
 reinforces a response after an
unpredictable number of responses
 average ratios
 like gambling, fishing
 very hard to extinguish because of
unpredictability
80
Schedules of Reinforcement
 Fixed Interval (FI)
 reinforces a response only after a
specified time has elapsed
 response occurs more frequently as
the anticipated time for reward
draws near
81
Schedules of Reinforcement
 Variable Interval (VI)
 reinforces a response at unpredictable
time intervals
 produces slow steady responding
 like pop quiz
82
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
83
Punishment
 Punishment
 aversive event that decreases the
behavior that it follows
 powerful controller of unwanted
behavior
84
Punishment
An aversive event that decreases the behavior
it follows.
85
Punishment
Although there may be some justification for
occasional punishment (Larzelaere & Baumrind,
2002), it usually leads to negative effects.
1.
2.
3.
4.
Results in unwanted fears.
Conveys no information to the organism.
Justifies pain to others.
Causes unwanted behaviors to reappear in its
absence.
5. Causes aggression towards the agent.
6. Causes one unwanted behavior to appear in
place of another.
86
Updating Skinner’s Understanding
Skinner’s emphasis on external control of
behavior made him an influential, but
controversial figure. Many psychologists
criticized Skinner for underestimating the
importance of cognitive and biological
constraints.
87
88
Cognition & Operant Conditioning
Evidence of cognitive processes during operant
learning comes from rats during a maze
exploration in which they navigate the maze
without an obvious reward. Rats seem to
develop cognitive maps (E.C. Tolman), or mental
representations, of the layout of the maze
(environment).
89
Cognitive Approach
This approach emphasizes abstract and subtle learning
that could not be achieved through conditioning or
social learning alone.
Some learning is not intentional, but occurs almost
accidentally—a situation called latent learning.
Learning that occurs, but is not apparent until there is
an incentive to demonstrate it
Expectancies are beliefs about our ability to perform an
action and to get the desired reward. Expectancies
affect learning.
90
Latent Learning
Such cognitive maps are based on latent
learning, which becomes apparent when an
incentive is given (Tolman & Honzik, 1930).
91
Cognition and Operant
Conditioning
 Overjustification Effect
 the effect of promising a reward for
doing what one already likes to do
 the person may now see the reward,
rather than intrinsic interest, as the
motivation for performing the task
92
Motivation
Intrinsic Motivation: The
desire to perform a
behavior for its own
sake.
Extrinsic Motivation:
The desire to perform a
behavior due to
promised rewards or
threats of punishments.
93
Biological Predisposition
Photo: Bob Bailey
Biological constraints
predispose organisms to
learn associations that
are naturally adaptive.
Breland and Breland
(1961) showed that
animals drift towards
their biologically
predisposed instinctive
behaviors.
Marian Breland Bailey
94
Skinner’s Legacy
Skinner argued that behaviors were shaped by
external influences instead of inner thoughts and
feelings. Critics argued that Skinner
dehumanized people by neglecting their free will.
.
Falk/ Photo Researchers,
Inc
95
Skinner’s Importance
Education: programmed
instruction
Work
Parenting
Personal
goals
96
Applications of Operant Conditioning
Skinner introduced the concept of teaching
machines that shape learning in small steps and
provide reinforcements for correct rewards.
LWA-JDL/ Corbis
In School
97
Applications of Operant Conditioning
Reinforcement principles can
enhance athletic performance.
In Sports
98
Applications of Operant Conditioning
Reinforcers affect productivity. Many companies
now allow employees to share profits and
participate in company ownership.
At work
99
Applications of Operant Conditioning
In children, reinforcing good behavior increases
the occurrence of these behaviors. Ignoring
unwanted behavior decreases their occurrence.
100
Operant vs. Classical Conditioning
101
Observational Learning
 Observational Learning (Albert Bandura)
 learning by observing and imitating others
 Modeling
 process of observing and imitating a
specific behavior
 Prosocial Behavior
 positive, constructive, helpful behavior
 opposite of antisocial behavior
102
Bandura's Bobo doll
study (1961) indicated
that individuals
(children) learn through
imitating others who
receive rewards and
punishments.
Courtesy of Albert Bandura, Stanford University
Bandura's Experiments
103
Albert Bandura: Hypothesis
=
• Believed we learn through observation and imitation
• Hypothesized that children would imitate aggressive
behavior they observed
104
Bandura’s Methodology
• Children watched films of adults beating Bobo dolls
• Three groups: aggression-rewarded, aggressionpunished, no consequences
• Children went into rooms with toys that they were told
not to play with
105
Bandura’s Results
EFFECT OF OBSERVED CONSEQUENCE ON
IMITATIVE BEHAVIOR
4
3.5
3
2.5
2
GIRLS
BOYS
1.5
1
0.5
0
MODEL
REWARDED
MODEL
PUNISHED
NO
CONSEQUENCES
• Children in the aggression-punished group expressed the
fewest aggressive behaviors toward the Bobo dolls
• Children in the other two groups expressed an equal
number of aggressive behaviors and were more
aggressive than children in the aggression-punished
106
group
Bandura’s Experiment
+
Viewing aggressive
behavior
=
Rewards for imitation
Aggressive behavior
• Children promised rewards for imitating the adult in the
film
• Now, all three groups were equally aggressive
• Children had learned the aggressive behavior from the
film, but those who saw the adults being punished were
107
less likely to act aggressively
Bandura’s Social
Learning Theory
• Relates to effects of violence and other images on TV
and in the movies
• Children imitate good and neutral behaviors as well
as bad ones
108
This series of photographs shows children
observing and modeling aggressive behavior.
Albert Bandura’s Bobo Doll Experiment
109
110
p. 244
Positive Observational Learning
Bob Daemmrich/ The Image Works
Fortunately, prosocial (positive, helpful) models
may have prosocial effects.
111
Applications of Observational Learning
Unfortunately,
Bandura’s studies
show that antisocial
models (family,
neighborhood or TV)
may have antisocial
effects.
112
Learning by Observation
© Herb Terrace
Higher animals,
especially humans,
learn through observing
and imitating others.
©Herb Terrace
The monkey on the right
imitates the monkey on
the left in touching the
pictures in a certain
order to obtain a
reward.
113
Reprinted with permission from the American
Association for the Advancement of Science,
Subiaul et al., Science 305: 407-410 (2004)
© 2004 AAAS.
Mirror Neurons
Neuroscientists discovered mirror neurons in the
brains of animals and humans that are active
during observational learning.
114
Learning by observation
begins early in life. This
14-month-old child
imitates the adult on TV
in pulling a toy apart.
Meltzoff, A.N. (1998). Imitation of televised models by infants.
Child Development, 59 1221-1229. Photos Courtesy of A.N. Meltzoff and M. Hanuk.
Imitation Onset
115
Gentile et al., (2004)
shows that children in
elementary school who
are exposed to violent
television, videos, and
video games express
increased aggression.
Ron Chapple/ Taxi/ Getty Images
Television and Observational Learning
116
Modeling Violence
Children modeling after pro wrestlers
Glassman/ The Image Works
Bob Daemmrich/ The Image Works
Research shows that viewing media violence
leads to an increased expression of aggression.
117
118
Famous last words???
Do what I say, not what I do—
This will teach you to hit your
brother—
Why do you do that, you know
you get in trouble for it—
119
CHRISTMAS CAROLS FOR THE PSYCHIATRICALLY CHALLENGED
Schizophrenia: Do You Hear What I Hear?
Multiple Personality Disorder: We Three Queens
Disoriented Are
Amnesia: I Don't Know if I'll be Home for Christmas
Narcissistic: Hark the Herald Angels Sing About Me
Manic: Deck the Halls and Walls and House and Lawn and
Streets and Stores and Office and Town and Cars and
Buses and Trucks and Trees and Fire Hydrants and ...
Paranoid: Santa Claus is Coming to Get Me
Borderline Personality Disorder: Thoughts of Roasting
on an Open Fire
Personality Disorder: You Better Watch Out, I'm Gonna
Cry, I'm Gonna Pout, Maybe I'll tell You Why
Obsessive Compulsive Disorder: Jingle Bells, Jingle
Bells, Jingle Bells, Jingle Bells, Jingle Bells,
Jingle Bells, Jingle Bells, Jingle Bells, Jingle Bells
...
Agoraphobia: I Heard the Bells on Christmas Day But
Wouldn't Leave My House
Autistic: Jingle Bell Rock and Rock and Rock and Rock
...
Senile Dementia: Walking in a Winter Wonderland Miles
From My House in My Slippers and Robe
Oppositional Defiant Disorder: I Saw Mommy Kissing
Santa Claus So I Burned Down the House
Social Anxiety Disorder: Have Yourself a Merry Little
Christmas While I Sit Here and Hyperventilate
120