Classical Conditioning

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Classical Conditioning

• Who discovered it?
• Two people
• Ivan Pavlov
• Edwin B. Twitmyer
• Pavlov is more famous.
• Twitmyer - discovered it by chance. But, did not
  follow it up.

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Basic Procedure

• Before conditioning
• CS
• UCS
• During conditioning
• CS - UCS
• Contiguous relationship
• After conditioning
• CS - CR

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Responses used to study conditioning

• Theoretically any response can be conditioned.
• But, in laboratory, we use a limited number of
  responses
• GSR/EDR - Galvanic Skin Responses
• Heart Rate
• Reflexive withdraw of finger

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• Eyeblink
• .Nictitating membrane - Rabbit
• .Conditioned emotional response (CER)
• Taste aversion
• Autoshaping

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CER

• Emotional response
• First studied by Watson
• Little Albert
• CS - white rat
• UCS - Banging of two steel pipe
• Response - Fear
• Is this like phobia? Dont know.

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CER with rats

• Phase I - Train a rat in Skinner box
• Phase II - Pavlovian fear conditioning
• CS (Buzzer) - UCS (Shock) - UCR (Fear)
• But, UCR is hypothetical.
• Phase III
• Present CS while the rat is pressing a bar in
  Skinner box.
• Rats will - Freeze in place

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Suppression Ratio

• Response during CS
• S.R.
• Response before CS during CS
• If conditioning is strong - SR should be 0
• Greater the number - Weaker the conditioning.

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Taste Aversion

• CS - Taste (saccharin)
• UCS - Chemical / X-ray radiation
• UCR - Sickness
• Result - Rats will avoid CS.
• Similar - too much alcohol.
• Unique conditioning situaiton

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Distinctive Features

• Easy to establish
• Other conditioning - Need to repeat CS - UCS
• Taste aversion - often one trial is needed.
• Long CS-UCS interval
• Other conditioning - short interval or else
• Taste aversion - even after 12 hours
• Strong associative effect
• Some stimuli are better combination.

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Associative effect

• Taste Audio/visual
• Sickness
• Electric Shock

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Autoshaping

• Often used with pigeons.
• CS - lighted circular disc
• UCS - food
• UCR - pecking
• Although pigeons do not have to do anything, they
  start to peck the disc
• CS - pecking disc

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How do we learn association?

• Neural mechanism is pretty complex
• Two pathways
• Long and short
• UCS is connected to both
• CS is connected to long
• After CS-UCS presentation, CS affects Purkinje
  cell that is connected to response

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What do we associate?

• Two theories
• S - S (CS - UCS)
• S - R (CS - UCR/CR)
• Which one is correct?
• A number of techniques

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Response prevention

• If we learn S - R association, then what would
  happen if you cannot make a response.
• CS - UCS - No response
• Stimulus is there, but no response there to be
  connected with.

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Experiment

• Damage spinal motor nerve of a dog.
• Shock a paw - cannot withdraw without motor
  nerve.
• CS - UCS - no response
• And, wait till the dog recovers from the damage.
  Then, present CS.
• Does it activate a response? Yes.

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But,

• It is too simplistic.
• Mere prevention of motor movement would not
  prevent the activation of nerve connection that
  is used to activate the response.

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Devaluation procedure

• After conditioning is established
• CS - CR
• Devalue UCS
• saturate animals with food
• induce radiation sickness
• Now present CS. What will happen?

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Assumptions

• S - S
• To respond CS will first activate memory of UCS.
• Memory of UCS then activate anticipatory
  response.
• S - R
• Stimulus directly activate response.
• After association is formed, UCS has nothing to
  do with activation of response.

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Results

• Devaluation of UCS decreased the amount of
  responding.
• UCS is a part of association you learn.

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Sensory Preconditioning

• Association can be formed between two neutral
  stimuli.
• Phase I
• CS1(snake) - CS2 (spider)
• Phase II
• CS2 (spider) - UCS (bitten) - UCR (Fear)
• Phase II
• CS1 activates CR (fear)

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Second Order Conditioning

• Similar situation
• Phase I
• CS1 - UCS
• Phase II
• CS2 - CS1
• Phase III
• CS2 activates CR

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Is it based on S-R or S-S?

• Rescorla - Devalued UCS
• Two possibilities
• S-R - CS2 is directly connected to the response.
  Devaluation of UCS should not affect response.
• S-S - CS2 will activate CS1 which will activate
  UCS which will activate an anticipatory response.
  Devaluation should affect response.
• Found - No effect of devaluation

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Why?

• It all depends on salience.
• Normal first order conditioning
• CS (buzzer) - UCS (shock)
• UCS is more salient - (S-S is formed)
• Second order
• CS2 (tone) - CS1(buzzer) - Response (fear)
• Response is more salient - (S-R is formed)

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Conclusion

• Learning is more flexible than expected by Pavlov
  and others.
• We can form either S-S or S-R or maybe both.