Pavlovian or Classical
Conditioning
Psychology 3306
Introduction
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Pavlov was working
on digestion, the rest
is history!
Figured that lots of
dogs’ behaviour may
have involved this
conditional redirection
of reflexes
Called the
phenomenon
‘Conditional Reflexes’
Conditional?
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Yes conditional
Was mistranslated
and ‘conditioned’!!!
So that is where we
get the term
conditioning from
Key terms
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Unconditioned Stimulus (UCS or US)
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Biologically relevant stimulus, that without
prior learning elicits an….
Unconditioned Response (UR or UCR)
 Conditioned Stimulus (CS)
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Neutral stimulus that with many CS – US
pairing elicits a
Conditioned Response (CR)
Cool conditioning stuff
Seems that pretty much any reflex can be
hooked up
 Today we concentrate on a few different
preparations
 Human eyeblink (rabbits too)
 CER (Conditioned emotional response) or
suppression
 SCR (Skin conductivity response)
 Taste aversion or food aversion
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Early theoretical ideas
Pavlov and stimulus substitution
 US replaced by CS
 However the CR is not always the same
as the UR
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Sign tracking takes this idea into account
actually
Weak, but intuitively pleasing
Perhaps physiology?
Pavlov thought there were CS and US
centres in the brain
 Hmmm, don’t seem to be, though some
responses are hooked up to specific brain
regions
 What is the connection though is it S – S
or S – R?
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S-S and S-R
US
CS
UR
If we could just get rid of that US –
UR bond…..
US
CS
UR
Rescrola (1973)
So, how do you get rid of a response that
is hard wired to a stimulus?
 Well, if you use CER, then your response
is startle right?
 How do you get rid of a startle reflex?
 Habituation!!
 (Bob is a smart man)
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Design
Group
Phase 1
Phase 2
Test
Habituation L -> N
Noise
Light
Control
Nothing
Light
L -> N
Results
Less suppression in Habituation group
 (In other words, more responding)
 Therefore, the connection MUST be S – S
 WOW!
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Some important properties of
Pavlovian conditioning
Acquisition
 Asymptote
 Extinction
 Spontaneous recovery
 Disinhibition
 Rapid Reacquisition
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Conditioned Inhibition
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Summation Test
B+
 A AB
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Retardation Test
A AB
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Generalization
So you will get a response (CR) to a given
CS.
 Just like with habituation, you will get
generalization
 Just like with habituation the less similar
the new CS is to the original, the less CR
you get
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Discrimination
Sort of the opposite of Generalization
 CS+ and CS Animal responds (CR) to S+ not to S Discrimination gets too hard you get
‘neuroses’
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Temporal Relationships
Simultaneous conditioning
 Short delay
 Long delay
 Trace conditioning
 Backwards
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Again, contiguity alone does not do the trick,
no surprise here
Correlation of events
CS- CSCSCSold control group, animal learns what?
CS + CSCS+
Rescorla Control
CS-
CS+
CS+
CS+
CS+
CS+
CS+
CS-
Conditional probability
The animal basically compares p(US | CS)
with p(US | no CS)
 The greater the difference the greater the
conditioning
 Long term more than short term
 Whole new take on learning
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Other paradigms
Higher order conditioning
 Sensory preconditioning
 Outside the lab too!
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Daily life
 Systematic desensitization
 Aversive counterconditioning
 Flooding
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