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PSY402
Theories of Learning
Chapter 3 (Cont.)
Indirect Conditioning
Applications of Conditioning
Midterm Results
Contemporary Theories

Classical Conditioning:
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Nature of the CR – stimulus
substitution theory, SOP and AESOP
theory
Predictiveness of the CS – RescorlaWagner associative model, comparator
theory, attentional theory,
retrospective processing approach.
Stimulus-Substitution Theory
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What is the nature of the CR – is it
just the UCR or is it different?
Pavlov – stimulus-substitution
theory:
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The CS stimulates the same areas of
the brain as the UCS, producing the
same response.
Activation of CS with UCS establishes
neural connection between brain areas.
Conditioned Opponent Response

The CR and UCR are often different:

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CR of fear is different than UCR of pain.
Siegel – best evidence of difference:
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Morphine (UCS) produced analgesia,
reduced pain (UCR)
Light or tone (CS) produced
hyperalgesia, increased pain (CR).
Rats remove paws from heat quickly
with CS, slowly with UCS.
Insulin (glycemia) works the same way
Drug Tolerance Overdoses

Elimination of a CS results in a
stronger response to the UCS, drug.


Extinction of responding to environmental cues strengthens drug response
Changing the context in which a
drug is administered increases
response to the drug.

Novel environment does not elicit an
opponent CR.
SOP Theory

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Sometimes Opponent-Process
theory (SOP) – explains why CR
varies.
UCS elicits primary A1 (fast) and
secondary A2 (longer) responses.

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A1 & A2 can be same or different.
Conditioning only occurs to A2 – the
CR is always an A2 response.

When A1 & A2 differ, UCR & CR differ.
SOP Explains Timing Effects
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None of the previous models explain
why the timing of CS-US matters.
SOP model requires that both CS
and UCS be in the A1 stage for
learning to occur.

With delay more elements of CS decay
from A1, becoming A2.
Activation of a memory node in SOP theory
Conditions during delay conditioning
Learning occurs only for
the elements whose A1
stages overlap
Conditions during trace conditioning
Without overlap, no
conditioning occurs
Conditions during backward conditioning
Inhibition is
conditioned
because the CS
A1 overlaps US
A2 stage
CS comes
after the US
Two-Phase Reactions

Shock – results in:
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A1 -- Initial agitated hyperactivity
A2 -- Long-lasting hypoactivity
(freezing)
CER (fear) elicited by CS is A2
Morphine – results in:

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A1 – sedation, analgesia & hypoactivity
A2 – hyperactivity two hours later &
hyperalgesia (greater pain sensitivity)
CR elicited by CS is A2 (hyper)
Affective Extension of SOP Theory

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Why do different A2 responses have
different optimal CS-UCS intervals?
Two distinct UCR sequences activate
distinct A1 & A2 sequences:



Sensory
Emotive
These distinct sequences can have
different strengths, time scales
(latencies), or eliciting CS’s.
Faster
Slower
Rescorla-Wagner Theory

There is a maximum associative
strength between CS and UCS.

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Strength gained on each training
trial depends on prior training.

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UCS determines the limit
More learning early, less later on
Rate of conditioning varies.
Conditioning of a CS depends on
prior conditioning to other stimuli.
UCS Preexposure Effect

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If the UCS is encountered without
the CS prior to pairing of the two,
less learning occurs.
UCS becomes associated with other
environmental stimuli (without CS).
Since there is a limit to association
strength, some is drained off by
such prior associations.

CS-UCS association is weakened.
Problems with Rescorla-Wagner

Overshadowing – salient cues have
more associative strength.
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Sometimes a salient cue potentiates
another cue instead of overshadowing.
Garcia says cues are indexed.
R-W says cues are seen as unitary
stimulus.
Unclear which explanation is
correct.
More Problems

CS preexposure effect – appearance
of CS without UCS prior to learning
weakens learning.

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Shouldn’t have any effect according to
Rescorla-Wagner theory, but it does.
Cue-deflation effect – extinction of a
more salient cue enhances learning
for the less salient cue.

Should be no change according to R-W.
Comparator Theory

If two CS’s are associated,
extinction of one should reduce
responding to the other.
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Sometimes true, other times not.
CS-UCS associations exist for many
stimuli but are exhibited only for
the strongest.

Comparator theory says the CS’s are
judged in relation to each other.
Organisms might learn about elemental or
configural CS nodes
Wagner & Brandon
Pearce
Attentional View
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Mackintosh – learned irrelevance
occurs during preexposure of CS.
Animals exposed to a novel stimulus
exhibit an orienting response.
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No orienting with preexposure.
Habituation results in failure of
conditioning – no attention is paid to a
habituated stimulus.
Pairing of CS/UCS in novel context
results in learning.
Retrospective Processing
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Most theories assume the level of
responding will be constant after
learning.
Baker & Mercier suggest association
can change after learning.
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Retrospective processing – CS-UCS
contingency reevaluated after learning.
Backward blocking – support for theory
Suggests animals have mental
representations, memory for events.
Applications of Conditioning

Treatment of phobias
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Treatment of addictions
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Systematic desensitization
Elimination of conditioned withdrawal
reactions
Enhancement of drugs used to treat
immune system disorders

Lupus, AIDS
How a Phobia Works
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A phobia is an unrealistic fear.
A learning experience causes fear to
become associated with a neutral
stimulus.
Avoidance prevents extinction.
The stimulus is generalized.
Eventually, too many experiences
must be avoided and a person’s
functioning is impaired.
Systematic Desensitization

Wolpe applied ideas from classical
conditioning to treatment of phobia.
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Reciprocal inhibition – an organism can
only feel one emotion at a time.
Mary Cover Jones – used
counterconditioning to extinguish fear.
Cats could be counterconditioned using
food.
Clinical Procedure
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Construct an anxiety hierarchy.
Teach a relaxation response.
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Cue-controlled relaxation.
Counterconditioning – pairing of
relaxation with imagined feared
stimuli, starting with least scary.
Assessment of whether the
treatment worked – interacting with
the feared stimulus.
Effectiveness of Desensitization
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Wolpe reported 90% success rate,
compared to 60% for
psychoanalysis.
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12-29 sessions
Relapse after 1-3 yrs easily treated.
Works with a wide range of fears.
Can also be used with anxiety
disorders.
Limitations on Desensitization
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The client must be able to vividly
imagine the feared stimulus.
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10% cannot do this.
Confrontation of a real rather than
an imagined object is more
effective.
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Difficult for the client to endure the
anxiety associated with this.
Virtual Reality Desensitization
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Graded height-related stimuli
presented via virtual reality were
effective in treating acrophobia.
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Subjects were able to endure real
stimuli after virtual treatment.
Successful in treating spider phobia.
Treatment of Withdrawal
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Conditioned withdrawal reaction –
environmental cues become
associated with withdrawal stage.
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Exposure to cues triggers symptoms.
Withdrawal motivates substance use.
Extinction by exposure to
environmental cues is needed.
Virtual reality also used to treat
addictions.
Treatment of Immune Disorders
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Lupus, AIDS are immune system
disorders.
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Treated using drugs that either boost
or suppress immune system response.
Classical conditioning can be used
to produce the results of such drugs
without the side effects or cost.
Immune System Conditioning
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Cyclophosphamide used to induce
nausea during flavor-aversion
learning also immunosuppressant.
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The saccharin-flavored water used as a
CS caused several rats to die.
The drug reaction occurred without
the drug – the CS evoked immune
system suppression.
Also works with other drugs.
Treatment of Lupus & AIDS
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Rats given saccharin paired with
cyclophosphamide had slower lupus
progression and lower mortality.
A girl treated for lupus was able to
use half as much drug when paired
with a distinctive taste and smell.
Sherbet paired with adrenaline
enhances immune functioning for
AIDS treatment.