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

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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