ClassicalPavlovian Conditioning

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Classical/Pavlovian Conditioning
Terminology
Unconditional Stimulus (US) a biologically
relevant event (food, sex, shock, etc)
Conditional Stimulus (CS) an event that
initially produces some orienting response, but
that has no strong biological consequences
(flashing lights, sounds, etc)
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Classical/Pavlovian Conditioning
Terminology
Unconditional Response (UR) the unlearned
reflexive response to the US (e.g., start
sweating when room gets too hot)
Conditional Response (CR) a learned response to
a CS that predicts a US (e.g., start salivating
at the smell of food)
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Classical/Pavlovian Conditioning
Pavlovs original experiment
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Classical/Pavlovian Conditioning
Pavlovs original experiment
CS (tone) initially has no effect on salivation
US (meat powder on tongue) unconditionally
elicits salivation (reflexive response)
CS and US paired on repeated trials
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Classical/Pavlovian Conditioning
Pavlovs original experiment
CS (tone) comes to elicit salivation when
presented by itself
CS has become associated with the US (it can
predict the US)
Associative learning allows for (for example)
anticipatory salivation, which makes eating a lot
easier
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Classical/Pavlovian Conditioning
Acquisition and Extinction
Learned associations must be acquired (i.e., they
have to be learned)
the learning curve
Increased amount of total learning over time
Decreased rate of learning over time
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Classical/Pavlovian Conditioning
Acquisition and Extinction
After sufficient conditioning, the association
will reach asymptote (maximum strength)
No further increases in associative strength,
regardless of number of additional trials
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Classical/Pavlovian Conditioning
Acquisition and Extinction
After an association between the CS and US has
been formed by pairing them repeatedly, what
happens if we start to present the CS by itself?
Extinction of the association CS no longer
elicits CR
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Classical/Pavlovian Conditioning
Acquisition and Extinction
What is extinction?
Not the unlearning of the association
- spontaneous recovery
- speed of reacquisition
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Classical/Pavlovian Conditioning
Acquisition and Extinction
Spontaneous Recovery
A previously extinguished CR may reappear at the
beginning of a subsequent conditioning session
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Classical/Pavlovian Conditioning
Acquisition and Extinction
Speed of Reacquisition
CR Strength
CR reaches asymptote faster on reacquisition than
during initial acquisition
Trial
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Classical/Pavlovian Conditioning
Acquisition and Extinction
Speed of Reacquisition
CR Strength
CR reaches asymptote faster on reacquisition than
during initial acquisition
Trial