factors influencing conditioning cs and us intensity, and attention to the cs temporal...
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Factors Influencing Conditioning
CS and US Intensity, and Attention to the CS
Temporal relationship Predictiveness Preparedness Redundancy
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CS Intensity Affects Rate
cs US
CS US
Weak CS
Strong CS
2
Suppression and CS Intensity
3
Another CS Intensity Effect
Overshadowing – the more salient CS wins if two CS are trained in compound
Group Stage 1 TestOvershadow Ax US crControl ax US CR
Note: Undercase letters stand for weak intensity CSs
4
CS Attention and Latent Inhibition
Group Phase 1 Phase 2 Test Experimental X,X,X… XUS cr Control ---- XUS CR
Because the CS is a benign stimulus it will lose the capacity to command ATTENTION if preexposed
Little “x” will eventually produce a robust CR
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The Influence of Intensity6
Exception: The effect of the CS on the intensity of the CR is sometimes seen when the subject is exposed to both the high and the low intensity CSs which are individually paired with the US on separate trials.
US Intensity Affects Rate and Asymptote
CS us
CS US
Weak US
Strong US7
Suppression and US Intensity
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CS
USDelay
CSUS
Trace
US
Explicitly Unpaired
Wea
ker
cond
itio
ned
resp
ondi
ng
Temporal Relationship
CS
CS
US
Simultaneous
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Time Conditioning10
No distinctive CS UCS is presented at regular intervals The passage of time is CS To determine whether conditioning has
occurred, the UCS is omitted and the strength of the CR is assessed
Indirect Conditioning11
Many stimuli develop the ability to elicit a CR “indirectly” i.e., a stimulus that is never itself paired
with a UCS comes to elicit the CR Two important ways for this to happen
are Higher-order conditioning Sensory preconditioning
Higher-Order Conditioning
Group Stage 1 Stage 2 Test ResultHOC AUS BA B? crControl CUS BA B? ziltch
HOC: A modest CR develops to B because if signals a “reminder” for the US, namely, the already conditioned A.
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Sensory Preconditioning
Group Stage 1 Stage 2 Test ResultSPC BA AUS B? crControl BA CUS B? ziltch
SPC: A modest CR occurs to B at test, because it signals the A, which is now a “reminder” for the US.
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CS-US Preparedness
From Garcia & Koelling, 1966 Back
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Are forward pairings enough to generate a CR? No!!!!!!!!
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Predictiveness of the CS
Predictiveness of the CS16
Predictiveness: the consistency with which the CS is experienced with the UCS, which influences the strength of conditioning.
The pairing of a CS and UCS does not automatically ensure that conditioning will occur.
A Contingency Experiment
Positively Correlated
CS
US
Chance of US per CS = 2/4 = .5
Chance of US outside CS = 0/10 = 0
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A Contingency Experiment
Uncorrelated
CS
US
Chance of US per CS = 2/4 = .5
Chance of US outside CS = 5/10 = .5
18
2/4 = .50/4 = .0
A Contingency Experiment
Negatively Correlated
CS
US
Chance of US per CS =
Chance of US outside CS = 5/10 = .5
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It’s a little like…
Animals are scientists, trying to make cause->effect predictions.
…trying to determine whether the US is contingent on the CS…lots of pairings in the zero contingency group
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Quantifying
p(US|CS) = proportion of CS trials with a US
p(US|no CS) = proportion of “background” only trials with a US
p = p(US|CS) - p(US|no CS)
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Some Examples
p(US|CS)
20/20 = 1.0
15/20 = .75
10/20 = .50
10/20 = .50
0/20 = 0
p(US|no CS)
0/60 = 0
6/60 = .10
30/60 = .5
45/60 = .75
60/60 = 1.0
p
1
2
3
4
5
• 1.0
• .65
• 0
• -.25
• -1.0
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P(US/no CS)
P(U
S/ C
S)
0 1.0
1.0
Negative
Positive
1
2
3 4
5
+1.0+.65
-.25
-1.0
Redundancy
Group Stage 1 Stage 2 Test ResultBlocking AUS ABUS B? crControl ABUS B? CR
Blocking: Limited or no acquisition of a CR to a second conditioned stimulus, B, when it is introduced alongside an already conditioned first conditioned stimulus , A.
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Extinction Paradigm25
Extinction of a conditioned response: when the conditioned stimulus does not elicit the conditioned response because the unconditioned stimulus no longer follows the conditioned stimulus
Loss of the CRs26
Hull considered the extinction process to be a mirror image of the acquisition. It is not. One reason for faster extinction than
acquisition is that extinction alters the motivation level via omission of the UCS.
Decline is also caused by the development of inhibition rather than erasing the first-learned CS-US association.
So, the CS is part “excitatory” and part “inhibitory” after the end of the last extinction trial
Evidence for new learning27
A rest period after the last extinction trial can produce spontaneous recovery. More rest causes more spontaneous recovery.
If extinction takes place in a different context than acquisition, a return to the original context of acquisition causes the immediate return of the CR (called ABA renewal).
Duration of CS Exposure28
As the duration of CS-alone exposure increases, the strength of the CR weakens Shipley found total duration of CS alone
exposure, not number of extinction trials is critical, but subsequent research has not always confirmed his result.
Exposure Therapy29
To increase sustained abstinence, some therapists have used a technique that involves exposing the addict to as many drug related cues as possible during extinction.
Withdrawal responses and drug cravings decrease as a result of exposure to drug-related cues.
Systematic Desensitization30
Developed by Joseph Wolpe Used to inhibit fear and suppress phobic
behavior SD uses counterconditioning and Wolpe
based it on three lines of evidence
Systematic desensitization31
Involves performing deep muscle relaxation techniques while first imagining, and then experiencing, anxiety-inducing scenes Relaxation involves cue-controlled
relaxation, a conditioned relaxation response that enables a word cue (e.g., “calm”) to elicit relaxation promptly
Stages32
Systematic desensitization consists of four separate stages: 1) construction of the anxiety hierarchy 2) relaxation training 3) counterconditioning – the pairing of
relaxation with the feared stimulus and exposure therapy
4) assessment of whether the patient can successfully interact with the phobic object
Hierarchies33
Hierarchies may be either Thematic: scenes all related to a basic
theme Spatial-temporal: based on phobic behavior
in which the intensity of the fear is determined by distance – either physical or temporal