Classical
conditioning
Forging connections between
formerly unrelated events
background
 It all started with Ivan Pavlov and his study
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of the digestive system
Research based on work with animals
Wildly successful – 1905 Nobel Prize
Studied the automatic connection between
food (meat) in the mouth and the flow of
digestive juices
UCS (meat in mouth) > UCR (saliva)
The big idea
 Start with an unconditioned reflex – an
automatic connection between a stimulus
and a response (meat>saliva)
 You can develop new automatic responses
by transferring responses from an UCS to
an originally neutral stimulus by
repetitively pairing them together
Let’s say that a
different way
 An air puff in the eye (UCS) will always
make us blink (UCR)
 Flashing a red card won’t
 But if we repetitively flash the red card,
shortly followed by the air puff, eventually,
 Just flashing the red card will make us
blink !
New terms
 The initially unremarkable red card is a
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neutral stimulus (NS)
The air puff is an UCS
The blink after just the puff is a UCR
The red card, once it causes a blink all by
itself, is a conditioned stimulus (CS)
The blink that follows just the red card is a
conditioned response (CR)
examples
 That particular corner at you high school
 The torturer’s black shoes
 The song from that certain summer that
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reminds you of …..
Pavlov’s assistants carrying the meat tray
The tone before the shock
The whistling of a V1 “shrieked”
Sexual fetishes
definitions
 Classical conditioning (CC) – process by
which an organism learns a new
association between two paired stimuli;
one of which was initially neutral the other
producing an unconditional reflex
 Unconditioned stimuli (UCS) – an event
that constantly and automatically elicits an
unconditioned response (UCR)
More definitions
 Unconditioned response (UCR) –
an action that an UCS elicits
 Conditioned response (CR) – action
that Conditioned Stimulus elicits; it
does not have to be identical to the
UCR
perspectives
 CC works across species, from the lowly
maggot to the most sophisticated human
being
 In habituation the UCS proved to be
meaningless and lost its power over
behavior
 In CC the initially meaningless CS
becomes crucial and works a heavy
influence on behavior
More perspectives
 CC prepares us for significant events by
identifying events that commonly predict
them
 Gives us advance warning of upcoming
threats and opportunities
 The more unfamiliar the CS or the more
powerful the UCS the faster the CR takes
Other aspects
 The process that establishes or
strengthens a CR is called
acquisition
 A CR can even be a thought
Unraveling the
connection
 Extinction – the decrease or
extinguishment of the conditioned
response
 In CC, extinction takes place when we
repeatedly present the CS without the
UCS following it
The return of the
cs>CR connection
 Extinction doesn’t erase the CS>CR
connection, it inhibits it
 Spontaneous recovery – the
temporary return of the extinguished
response after a delay
All together now
 First we build the CS>CR connection
through acquisition,
 Then we unravel it through
extinction,
 If we then stop presenting the CS for
a while, once we resume its use,
 The CR will return, but not for long,
unless it is again paired with the UCS
Extending the
connection
 The CR can occur even without
presentation of the exact CS which formed
it, if the new CS is similar enough
 Stimulus generalization – the extension
or broadening of a CR from the original CS
to another, similar stimulus
 The more similar the entire setting is, the
more likely the new connection will form
Narrowing
connections
 If differing stimuli, although quite
similar to the CS, are never, or rarely,
followed by the UCS, then the CR will
not emerge
 Stimulus generalization – differing
responses to differing stimuli that
have been followed by differing
events
What factor is key
to cc?
 What causes the connection to form?
 Pavlov thought that the most important
element in acquisition was how closely the
UCS followed the CS.
 We call it temporal contiguity or “nearness
is good”
 After all, the longer the break between the
CS and the UCS, the weaker the
connection.
Is it just timing?
 The concept of blocking.
 If a CS/CR link has been established,
pairing a new CS with the old CS will not
work.
 This is true even if the timing is perfect for
the new CS.
 So, nearness in time is not enough.
The power of
prediction
 It’s reliability that counts, the CS’
ability to accurately and consistently
predict the UCS.
 The UCS must be more likely to occur
after the CS.
The big picture
 CC involves visceral reactions involving
the sympathetic nervous system – you feel
it in your gut.
 It prepares us for important challenges
and threats.
 But it does not tell us what to do.
 For how we learn voluntary, planned
behaviors we turn to operant conditioning.