Download Classical Conditioning

The World of Psychology
Wood and Wood
Learning
Chapter 5
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Copyright © Allyn & Bacon 2002
Learning

When people think about academic
Psychology this is usually what they picture.
A lot of the first “real” scientific Psychology
was done on learning.
Probably the topic that moved Psychology
from a branch of Philosophy to a branch of
Physical Science.
Copyright © Allyn & Bacon 2002
Learning: Modern Definition

Learning may be defined as a relatively
permanent change in behavior, knowledge,
capability, or attitude that is acquired through
experience and cannot be attributed to illness,
injury, or maturation.
Copyright © Allyn & Bacon 2002
Measuring Learning: Problem Statement

Psychologists cannot observe learning
directly but must infer that it has occurred.
They draw inferences from changes in
observable behavior or in measurable
capabilities and attitudes.
Copyright © Allyn & Bacon 2002
More Learning
Learning does not always result in an
observable change in behavior. *
Motivation – we “want” to
Context – Only “fits in” occasionally
Capability – Requires external conditions
* Note difference with textbook
Copyright © Allyn & Bacon 2002
1
How do organisms learn?

 Through many different avenues.
 Habituation
 Classical conditioning
 Instrumental or operant conditioning
 Cognitive learning
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2
How do organisms learn?
We will discuss
three basic forms of learning:
1. Classical conditioning
2. Operant conditioning
3. Observational learning
(a type of cognitive learning).
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Classical Conditioning

Pavlov
Conditioned Stimulus
Unconditioned Stimulus
Unconditioned Response
Conditioned Response
DR. IVAN PAVLOV
(1849-1936)
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Pavlov

Ivan Pavlov (1849–1936)

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organized and directed research in physiology
at the Institute of Experimental Medicine in
St. Petersburg, Russia
from 1891 until his death 45 years later.
Conducted experiments on
the physiology of digestion
He won a Nobel Prize in 1904
First time Nobel Prize won by a Russian.
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Careful Research

 Experimental apparatus eliminated:
 Vibration, noise, temperature extremes, odors, drafts
 Nothing could influence the animals except the
conditioning stimuli to which they were exposed.
(Schultz, 1975, pp. 187–188)
 Dogs were isolated inside soundproof cubicles
 Dogs were put in harnesses to restrain their movements.
 Experimenters were in an adjoining cubicle
 Dogs were observed through a one-way mirror.
 Dogs were presented with food by remote control,
 Other conditioning stimuli also presented by remote control
 A tube carried the saliva from the dog’s mouth to a container where
it was measured.
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The Apparatus
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Definitions Related to
Classical Conditioning

 Classical conditioning: A learning process through which
one stimulus comes to predict the occurrence of another
stimulus and to elicit a response similar to or related to the
response evoked by that stimulus.
 Classical conditioning is sometimes referred to as
 respondent conditioning
 Pavlovian conditioning
 Stimulus (STIM-yu-lus): Any event or object in the
environment to which organism responds
plural is stimuli.
 Reflex is an involuntary response to a particular stimulus.
 Reflexes are made up of both a stimulus and a response.
Copyright © Allyn & Bacon 2002
Unconditioned Stimulus

Unconditioned means “not learned.”*
 Any stimulus that without learning will automatically
cause an unconditioned response is called an
unconditioned stimulus (US).
 Salivation in response to food is an unconditioned reflex
because it is

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inborn,
automatic,
unlearned response to a
 Unconditioned
reflexes are “built into” NS
* Differs from textbook
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Examples of
Unconditioned Stimuli

 loud noise
 light in eye
 puff of air in
 touching hot stove
startle
pupil contraction
eye blink
hand withdrawal
 Is Chinese startle response learned?
 Others?
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Unconditioned Response

Unconditioned Response (UR):
A response that is invariably elicited by the
unconditioned stimulus without prior
learning.
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Conditioned Reflex/Response

Conditioned Reflex:
A learned reflex rather than a
naturally occurring one.
 This terminology is confusing!
 I prefer Conditioned Response.
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Classical Conditioning Cont.

Important Terms:
 Extinction
 Spontaneous Recovery
 Generalization
 Discrimination
 Higher-Order Conditioning
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Conditioned Stimulus
 Conditioned means “learned.”*
Any stimulus that comes to elicit a conditioned response
through Classical Conditioning is called a conditioned stimulus
(US).
Salivation in response to food is an unconditioned reflex
because it is
 inborn,
 automatic,
 unlearned response to a
Unconditioned reflexes are “built into” NS
Copyright © Allyn & Bacon 2002
Classical Conditioning Simplified
Pictorial View
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Classical Conditioning:
the Contemporary View
 The Cognitive Perspective:
Prediction is the critical element
 Biological Predispositions:
Their role in classical conditioning
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Factors Influencing Classical
Conditioning

 How reliably the CS predicts the US
 The number of pairings of the CS and the US
 The intensity of the US
 The temporal relationship between
the CS and the US
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Classical Conditioning:
The Diagram

Event or Object
Organism responds to.
Unconditioned
S2
Reflex
Evoked
S1
Event or Object
Organism Perceives.
Conditioned
S2
CS
R2
CR
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R1
UR
US
Elicited
Prediction
End 5a
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Higher-Order Conditioning

 Classical conditioning is not limited to just two procedures:
 (1) by the pairing of a conditioned stimulus with an unconditioned stimulus
 (2) through generalization.
 Classical conditioning can occur in another way:
 Higher-order conditioning.
 Higher-order conditioning takes place when:
 a neutral stimulus is paired with an existing conditioned stimulus
 a neutral stimulus becomes associated with an existing conditioned stimulus
 a neutral stimulus gains the power to elicit the same conditioned response.
 Higher-order conditioning can account for many of the positive and
negative feelings toward stimuli that people associate with other people or
situations.
Copyright © Allyn & Bacon 2002
Important Definitions
 spontaneous recovery:
The reappearance of an extinguished response (in a weaker form) when an
organism is exposed to the original conditioned stimulus following a rest
period.
 generalization:
In classical conditioning, the tendency to make a conditioned response to a
stimulus similar to the original conditioned stimulus.
 discrimination:
The learned ability to distinguish between similar stimuli so that the
conditioned response occurs only to the original conditioned stimulus but
not to similar stimuli.
 higher-order conditioning:
Conditioning that occurs when a neutral stimulus is paired with an existing
conditioned stimulus, becomes associated with it, and gains the power to
elicit the same conditioned response.
Copyright © Allyn & Bacon 2002
Watson, Little Albert, and Peter
Or Learning to Fear

Why we learned to dislike Watson.
 In the laboratory, Rayner presented Little Albert with a white rat.
 As Albert reached for the rat, Watson struck the steel bar with a
hammer just behind Albert’s head.
 This procedure was repeated, and Albert “jumped violently, fell
forward and began to whimper” (Watson & Rayner, 1920, p. 4).
 A week later, Watson continued the experiment, pairing the rat
with the loud noise five more times.
 Then at the sight of the white rat alone, Albert began to cry.
Copyright © Allyn & Bacon 2002
Watson, Little Albert, and Peter
Or Learning to Fear
Why we learned to dislike Watson.
When Albert returned to the laboratory 5 days
later, the fear had generalized to:
a rabbit
somewhat less, to a dog, a seal coat, Watson’s hair,
and a Santa Claus mask.
After 30 days Albert’s fears were still evident,
although less intense.
Albert moved away still afraid of fuzzy things
Copyright © Allyn & Bacon 2002
Other Considerations

The ideal time between conditioned and unconditioned
stimuli is about 1/2 second
 varies according to the type of response being conditioned
 the nature and intensity of the conditioned stimulus
 the nature and intensity of the unconditioned stimulus
Some studies indicate that the age of the subject may
also be a variable affecting the optimal time interval
If the conditioned stimulus occurs too long before the
unconditioned stimulus, an association will not form.
The one notable exception to this general principle is
conditioning of taste aversions.
Copyright © Allyn & Bacon 2002
Operant Conditioning

Thorndike’s Law of Effect
Reinforcement
Shaping
Extinction
Generalization and Discrimination
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Thorndike and the Puzzle Box

American psychologist Edward Thorndike
Preceded Pavlov
designed and conducted experiments to study animal
intelligence.
attempted to answer questions about the nature of learning
across animal species.
investigated trial-and-error learning in cats, dogs,
chicks, and monkeys.
best-known experiments placed a hungry cat in a wooden
box with slats called a puzzle box.
After many trials, the cat learned through trial and error to open
the door almost immediately after being placed in the box.
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Thorndike’s Puzzle Box
http://fates.cns.muskingum.edu/~psych/psycweb/history/thorndike.htm#Theory
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Thorndike’s law of effect

The consequence, or effect, of a response will
determine whether the tendency to respond in the
same way in the future will be strengthened or
weakened.
Responses closely followed by satisfying
consequences are more likely to be repeated.
Connections between a stimulus and a response will
be strengthened if the response is followed by a
satisfying consequence and weakened if the response
is followed by discomfort.
Copyright © Allyn & Bacon 2002
Thorndike builds a Foundation
Thorndike (1898) insisted that it was
“unnecessary to invoke reasoning” to explain
how the learning took place.
Thorndike’s law of effect formed the
conceptual starting point for B. F. Skinner’s
work in operant conditioning.
Copyright © Allyn & Bacon 2002
Operant Conditioning

A type of learning in which the consequences
of behavior are manipulated in order to
increase or decrease that behavior
Copyright © Allyn & Bacon 2002
Operant Vs Classical Conditioning
In classical conditioning

Organism does not learn a new response
O learns to make an old or existing response to a new stimulus.
O cannot help but respond in expected ways.
Classically conditioned responses are involuntary or reflexive
Process begins with stimulus to evoke a reflexive response.
 In operant conditioning
O learns a new response
O learns to apply voluntary responses.
 Response comes first, the consequence that follows tends to
modify this response in the future.
Consequences of behavior manipulated to increase or decrease
response frequency or to shape an entirely new response.
Behavior that is reinforced tends to be repeated.
Process does not begin with a stimulus to elicit a response.
Copyright © Allyn & Bacon 2002
Operant Terms Definitions

A reinforcer is anything that strengthens or increases
the probability of the response it follows. Behavior
that is ignored or punished is less likely to be
repeated.
shaping: An operant conditioning technique that
consists of gradually molding a desired behavior
(response) by reinforcing responses that become
progressively closer to it.
Skinner box: A soundproof chamber with a device
for delivering food and detecting behavior - usually
automatically.
Copyright © Allyn & Bacon 2002
Reinforcement
One Dichotomy +/-

Positive - a reward that follows a response and increases
the probability that the response will be repeated.
Negative - the termination of an unpleasant stimulus
after a response that increases the probability that the
response will be repeated.
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Reinforcement
another Dichotomy

Primary - fulfills basic physical need for survival
Secondary - NS that becomes reinforcing after
repeated pairings with other reinforcers.
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Reinforcement Schedules
(Partial Reinforcement)

Fixed-Ratio - reinforcer is given after a fixed
number of correct responses
Variable-Ratio - reinforcer is given after a variable
number of correct responses
Fixed-Interval - reinforcer is give after first correct
response after passage of fixed interval of time
Variable-Interval - reinforcer is given after first
correct response following a variable interval of
time
Copyright © Allyn & Bacon 2002
Reinforcement Schedules
http://www.fiu.edu/orgs/psych/eab_3002/interact/schedule.htm
Copyright © Allyn & Bacon 2002
Shaping Just a Bit at a Time

B. F. Skinner developed this technique
Particularly effective in conditioning complex behaviors.
Process:
 Don’t wait for desired response and then reinforcing it
 Reinforce any movement in the direction of desired response
 Gradually guide responses closer and closer to the goal.
Copyright © Allyn & Bacon 2002
The Textbook’s Skinner Box Bull
Skinner designed a soundproof apparatus, commonly
called a Skinner box, with which he conducted his
experiments in operant conditioning. One type of box
is equipped with a lever, or bar, that a rat presses to
gain a reward of food pellets or water from a
dispenser. A record of the animal’s bar-pressing is
registered on a device called a cumulative recorder,
also invented by Skinner. Through the use of shaping,
a rat in a Skinner box is conditioned to press a bar for
rewards. It may be rewarded first for simply turning
toward the bar. The next reward comes only when the
rat moves closer to the bar. Each step closer to the bar
is rewarded. Next the rat must touch the bar to
receive a reward; finally, it is rewarded only when it
presses the bar.
Copyright © Allyn & Bacon 2002
Skinner Box
http://www.biozentrum.uni-wuerzburg.de/genetics/behavior/learning/SkinnerBox.html
Click for
German
Skinner Box
Photos
http://www.nici.kun.nl/~voogd/skinner/index.html
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Skinner’s Version
One pleasant Saturday afternoon I surveyed my supply of dry pellets and, appealing to certain elemental theorems in arithmetic, deduced
that unless I spent the rest of that afternoon and evening at the pill machine, the supply would be exhausted by ten-thirty Monday morning.
Since I do not wish to deprecate the hypothetico-deductive method, I am glad to testify here to its usefulness. It led me to apply our second
principle of unformalized scientific method and to ask myself why every press of the lever had to be reinforced. I was not then aware of
what had happened at the Brown Laboratories, as Harold Schlosberg later told the story. A graduate student had been given the task of
running a cat through a cat through a difficult discrimination experiment. One Sunday, the student found the supply of cat food exhausted.
The stores were closed, and so, with a beautiful faith in the frequency-theory of learning, he ran the cat as usual and took it back to its
living cage unrewarded. Schlosberg reports that the cat howled its protest continuously for nearly forty eight hours. Unaware of this, I
decided to reinforce a response only once every minute and to allow all other responses to go unreinforced There were two results: (a) my
supply of pellets lasted almost indefinitely, and (b) each rat stabilized at a fairly constant rate of responding.
Now, a steady state was something I was familiar with from physical chemistry, and I therefore embarked upon the study of periodic
reinforcement. I soon found that the constant rate at which the rat stabilized depended upon how hungry it was. Hungry rat, high rate; less
hungry rat, lower rate. At that time I was bothered by the practical problem of controlling food deprivation. I was working half time at the
Medical School (on chronaxie of subordinations) and could not maintain a good schedule in working with the rats. The rate of responding
under periodic reinforcement suggested a scheme for keeping a rat at a constant level of deprivation. The argument went like this:
Suppose you reinforce the rat, not at the end of a given period, but when it has completed the number of responses ordinarily emitted in
that period. And suppose you use substantial pellets of food and give the rat continuous access to the lever. Except for periods when the rat
sleeps, it should operate the lever at a constant rate around the clock. For, whenever it grows hungrier, it will work faster, get food faster,
and become less hungry, while whenever it grows slightly less hungry, it will respond at a lower rate, get less food, and grow hungrier. By
setting the reinforcement at a given number of responses, it should even be possible to hold the rat at any given level of deprivation. I
visualized a machine with a dial which one could set to make available, at any time of day or night, a rat in a given state of deprivation.
Of course, nothing of the sort happens. This is fixed-ratio rather than fixed- interval' reinforcement and, as I soon found out, it produces a
very different type of performance. This is an example of a fifth unformalized principle of scientific c practice, but one which has at least
been named. Walter Cannon described it with a word invented by Horace Walpole:serendipity the art of finding one thing while looking
for something else.
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Superstitious Behavior

Sometimes a reward follows a response but
the two are not related.
Superstitious behavior occurs if an individual
falsely “believes” that a connection exists
between an act and its consequences.
Copyright © Allyn & Bacon 2002
Extinction

Responses followed by reinforcers tend to be
repeated and responses no longer followed by
reinforcers will occur less and less frequently
and eventually die out.
In operant conditioning, extinction occurs
when reinforcers are withheld.
Spontaneous recovery also occurs in operant
conditioning.
Copyright © Allyn & Bacon 2002
Generalization and Discrimination
Generalization occurs in operant conditioning.
Generalization occurs when a reinforced stimuli causes
response to non reinforced stimuli which have common
characteristics.
Discrimination in operant conditioning involves
learning to distinguish between a stimulus that has been
reinforced and other stimuli that may be very similar.
Discrimination is learned when the response to the
original stimulus is reinforced but responses to similar
stimuli are not reinforced.
Copyright © Allyn & Bacon 2002
Factors Influencing Operant
Conditioning

The magnitude of
reinforcement
The immediacy of
reinforcement
The level of motivation
of the learner
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Other Issues in Operant
Conditioning

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Punishment
Escape Learning
Avoidance Learning
Learned Helplessness
Biofeedback
Behavior Modification
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Comparison
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Cognitive Learning

Insight
Latent Learning
Cognitive Maps
Observational Learning
 Learning Aggression
Copyright © Allyn & Bacon 2002
Post Pavlov and Skinner
A growing number of psychologists
stress the role of mental processes.
 broaden the study of learning to include such
cognitive processes as:
thinking,
knowing,
problem solving,
remembering,
 forming mental representations.
According to cognitive theorists, these processes are
critically important in a more complete, more
comprehensive view of learning.
Copyright © Allyn & Bacon 2002
Insight

The sudden realization of the relationship
between elements in a problem situation,
which makes the solution apparent.
http://sun.science.wayne.edu/~wpoff/cor/mem/cogninst.html
http://www.ship.edu/~cgboeree/insight.html (Gestalt View of Insight)
Copyright © Allyn & Bacon 2002
Latent Learning

Learning that occurs without apparent
reinforcement but that is not demonstrated
until sufficient reinforcement is provided.
http://website.lineone.net/~nene/learning.htm
http://sun.science.wayne.edu/~wpoff/cor/mem/cognlatn.html
A NEW FORMULA FOR BEHAVIORISM [1]
Edward Chace Tolman (1922)
First published in Psychological Review, 29, 44-53.
Copyright © Allyn & Bacon 2002
Cognitive Maps
A mental representation of a spatial
arrangement such as a maze.
http://www.cogs.susx.ac.uk/lab/nlp/gazdar/teach/atc/1999/web/verenah/
http://www.alleydog.com/cognotes/cogmap.html
http://www.people.memphis.edu/~kshawes/cogmap/1
COGNITIVE MAPS IN RATS AND MEN[1]
Edward C. Tolman (1948)
First published in The Psychological Review, 55(4), 189-208.
Copyright © Allyn & Bacon 2002
Observational Learning

Learning by observing the behavior of others and
the consequences of that behavior; learning by
imitation.
Another name for observational learning: modeling
Also called Social Learning Theory
Occurs when an observer's behavior changes after
viewing the behavior of a model.
http://www.funderstanding.com/observational_learning.cfm
http://mentalhelp.net/psyhelp/chap4/chap4g.htm
Copyright © Allyn & Bacon 2002
Observational Learning 2
Model: The individual who demonstrates a
behavior or serves as an example in observational
learning.
Note: Models may also be physical constructs that
demonstrate a behavior, process, method, or result.
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End Chapter 5
Copyright © Allyn & Bacon 2002