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Human LearningTopic 3: Part 3 Respondent Conditioning

Mechanisms and Function

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Contingency & Contiguity

Contingency is a major key!

the degree of prediction from the CS to the US effects the amount of conditioning

Rescorla – p(us/cs) and p(us/no cs) Vary these probabilities using a 2 minute tone at random intervals

.4 that the US would occur during a CS; .2 a US would occur during a no CS

Contiguity also plays a role

The shorter the ISI or TI the stronger the conditioning

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Compound Stimuli

Two or more stimuli occurring together (sound and sight - CR) then paired with a US

Can test the effects of this by presenting one of the CSs alone after pairings

Often you get conditioning to both

But not always

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Blocking

Kamin – conditioned suppression procedure (css = light, tone, light tone; cr = shock)

Two groups: blocking and control

One stimulus seems to block conditioning to the other – no new predictability.Group Phase 1 Phase 2 Test

PhaseResult

Blocking 1 Light Light/tone Tone Tone elicits no CR

Control ------- Light/tone Tone Tone elicits CR

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Overshadowing

Intensity of the CS effects conditioning trials

Loud CS and soft CS US = CR

Test with either CS

+CS = CR -CS ≠ CR

But you can then use the –CS by itself and get conditioning

One seems to overshadow the other

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Experience with the CS

Latent inhibition

Presence of a CS in the absence of the US Delays acquisition in

the future

Prediction is decreased

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AcquisitionStr

ength

of

CR

Number of trials

• CR is increasing in strength•Learn more on early trials than on later ones