Transcript Document

General Psychology 1
Learning:
Classical Conditioning – Module 20
March 17, 2005
Class #16
What is Learning?
 Learning is a relatively permanent change in
behavior due to experience
 We learn primarily by identifying relationships
between events and noting regularity of
patterns in our world
Ivan Pavlov (1849-1936)
 Was a research physiologist, not a
psychologist
 At age 33, earns MD degree
 Spends next 20 years studying
the digestive system
 Russia’s first Nobel Prize winner
in 1904
 Very impressive stuff but not what
he’s remembered for…
 Rather its his novel work done
over the final 30 years of his life
that earns him his place in
scientific history
Sometimes its just better to be
lucky…
 Pavlov serendipitously discovers the
conditioning response
 He’s working on digestive system and is
measuring the amount of saliva his dogs
were producing when food was presented to
them…
 But then “psychic secretions” start messing
up his experiments
Ivan Pavlov
 First, considered them as an annoyance
but then realized he had stumbled onto
something of even greater importance…

Devotes rest of life until his death at age 86
exclusively to the study of learning
Classical Conditioning
Important Terms
 Acquisition
 Initial learning of the stimulus-response
relationship
 Neutral stimulus (NS)
 In classical conditioning, the NS does not initially elicit
the response that is being studied
 Unconditioned stimulus (UCS)
 In classical conditioning, this is the stimulus that elicits
the unconditioned response (UR) without conditioning
Classical Conditioning
Important Terms
 Conditioned stimulus (CS)
 In classical conditioning, this is the stimulus which
comes to elicit a new response by virtue of pairings
with the unconditioned stimulus
 Unconditioned response (UCR)
 In classical conditioning, the automatic (involuntary),
unlearned reaction to a stimulus
 Conditioned response (CR)
 A learned response elicited as a result of pairings
between that NS and an UCS
Classical Conditioning
 Also, keep in mind the influences of such things
as timing, predictability (expectancy), signal
strength and attention…
Classical Conditioning
 A form of learning in which a neutral stimulus
(NS), is paired with an unconditioned stimulus
(US)…

In effect, what has to be learned is the relation between these
two stimuli
 Eventually, through this learning process the NS
evokes a response which once it did not thus
making it a conditioned stimulus (CS)…

This is accomplished by repeatedly pairing a neutral stimulus
with a stimulus that already triggered a reflexive response until
the NS alone is evoking that same reflexive response
Classical Conditioning
 Behaviors that are classically conditioned are
those which involve the learning of involuntary
(reflexive) responses -- responses over which
the learner has no control and to which he or she
responds reflexively or "automatically“

Examples include a dog salivating at the sound of the
dinner bell, a horse flinching or shying away at a
blowing piece of paper, someone becoming nauseous
at sight of "creamy-looking" food when mayonnaise
once made them ill, etc.
Pavlov’s Classical
Conditioning Experiments
 UCS ------------------------------------------- UCR
(food)
(salivation)
 NS -------------------------------------------- NO RESPONSE
(tone)
(no salivation)
 NS + UCS ----------------------------------- UCR
(tone) (food)
(salivation)
* This is repeated several times…

CS --------------------------------------------- CR
(tone)
(salivation)
Classical Conditioning:
Extinction
 The decline or disappearance of the CR in
the absence of the UCS
Classical Conditioning
Extinction
UCS ---------------------------------------------- UCR
NS ----------------------------------------------- NO RESPONSE
NS + UCS -------------------------------------- UCR
*Repeated several times
CS ------------------------------------------------ CR

Extinction process is initiated:
CS -----------------------------------------------
CS -----------------------------------------------
CS -----------------------------------------------
CS -----------------------------------------------

CR
CR
CR
CR
Eventually we get………..
NS --------------------------------------------- NO RESPONSE
(tone)
(no salivation)
Classical Conditioning:
Reconditioning
 Quick relearning of conditioned response after
the extinction trials
Classical Conditioning
Reconditioning
UCS ----------------------------------------------------- UCR
NS ------------------------------------------------------ NO RESPONSE
NS + UCS --------------------------------------------- UCR
* Repeated several times
CS ------------------------------------------------------
CS ------------------------------------------------------
CS ------------------------------------------------------
CS ------------------------------------------------------
CR
CR
CR
CR
NS ----------------------------------------------------- NO RESPONSE

Reconditioning process is initiated:
NS + UCS -------------------------------------------- UCR
CS ----------------------------------------------------- CR
Classical Conditioning:
Spontaneous Recovery
 An extinguished CR will temporarily reappear if
after a time delay the CS is presented again
even without the UCS
 This is a reappearance of a CR after extinction
despite no further CS-UCS pairings
Classical Conditioning:
Stimulus Generalization
 After a CR is acquired, stimuli that are similar
but not identical to the CS also will elicit the
response – but to a lesser degree
 The greater the similarity between a new
stimulus and the CS the stronger the CR will
be
Classical Conditioning
Generalization
 UCS --------------------------------------------- UCR
(food)
(salivation)
 NS + UCS ------------------------------------  UCR
(low tone) (food)
* Repeated several times
(salivation)
 NS + UCS ------------------------------------- UCR
(medium tone) (food)
*Repeated several times
(salivation)
 NS + UCS ------------------------------------- UCR
(high tone) (food)
* Repeated several times
(salivation)
Classical Conditioning
Generalization
 CS --------------------------------------------- CR
(high tone)
(salivation)
 CS -------------------------------------------- CR
(low tone)
(salivation)
 CS -------------------------------------------- CR
(medium tone)
(salivation)
Classical Conditioning:
Stimulus Discrimination
 Organisms learn to differentiate among similar
stimuli
 In Pavlov's early experiments he could get
dogs to discriminate between the pitches of
certain tones
Classical Conditioning:
Discrimination

UCS ------------------------------------------------------ UCR
(food)
(salivation)

NS ------------------------------------------------------- NO RESPONSE
(low tone)
(no salivation)

NS ------------------------------------------------------ NO RESPONSE
(medium tone)
(no salivation)

NS ----------------------------------------------------- NO RESPONSE
(high tone)
(no salivation)

NS + UCS -------------------------------------------- UCR
(high tone) (food)
(salivation)
* Repeated several times
Classical Conditioning
Discrimination
 CS ------------------------------------------------------ CR
(high tone)
(salivation)
 NS ----------------------------------------------------- NO RESPONSE
(low tone)
(no salivation)
 NS ---------------------------------------------------- NO RESPONSE
(medium tone)
(no salivation)
 CS ----------------------------------------------------- CR
(high tone)
(salivation)
Kamin (1969)
 Experiment 1:
Phase 1
Phase 2
Phase 3
Tone ---- Shock
Tone/Light ----Shock
Tone---???
Light---???
Kamin (1969)
Experiment 2:
Phase 1
Phase 2
Phase 3
Eliminated
Tone/Light ----Shock
Tone---???
Light---???
Classical Conditioning:
Second-order conditioning
Phase 1:
UCS (Food)

NS1 (Tone)

NS1+ UCS (Tone/Food)

* Repeated several times
CS (Tone)

Phase 2:
NS2/CS (Light/Tone)

* Repeated several times
Phase 3:
NS2 (Light)

UCR (salivation)
NO RESPONSE
UCR (salivation)
CR (salivation)
CR (salivation)
What do you think
happens?
Second-order conditioning
Here’s a summary of previous slide:
Phase 1
Tone  Food
(salivation)
Phase 2
Light Tone
(salivation)
Phase 3
Light
(?????)
 Here, a CS that has previously been
conditioned is now used to condition
another NS
Rescorla (1987):
Second-order conditioning
Phase 1:
UCS (Food)
NS
NS + UCS (Tone/Food)
* Repeated several times
CS (Tone)



UCR (salivation)
NO RESPONSE
UCR (salivation)

CR (salivation)
Phase 2:
UCS (Food/Poison)

CR (salivation)
Phase 3:
CS (Tone)

What do you think
happens?
Rescorla (1987)
Here’s a summary of previous slide:
Phase 1
Tone  Food
(salivation)
Phase 2
Food (Poison)
(salivation)
Phase 3
Tone
(?????)
 What do you think happened???
Classical Conditioning:
Drug Tolerance Example
 Drug Tolerance



Drugs have less of an effect when taken repeatedly
(less of a high)
Drug users crave more of the drug despite its
lessening effects
It appears that certain drugs trigger our body to call
upon its defenses against the effects of the drug
Drug Tolerance
 Siegel et al. (1982)


Demonstrated that classical conditioning principles
might be in effect during drug-injecting episodes…
Possible reason for overdoses???
Siegel’s theory…

UCS ---------------------------------------------- UCR
(drug)
(anti-drug defenses)

NS ----------------------------------------------- NO RESPONSE
(injection ritual)
(no defenses)

NS + UCS -------------------------------------- UCR
(injection ritual) + (drug)
(anti-drug defenses)
* Repeated several times

CS ----------------------------------------------- CR
(injection ritual)
(anti-drug defenses)
Siegel’s theory…
 Familiar setting----------------------- anti-drug defenses
(usual time, place, etc)
(body reacts)
 New setting ---------------------------- no defenses
(place, time are different)
(body doesn't react)
 The same dosage now becomes an overdose –
they get too high as their bodies have been
fooled by the new procedure
Siegel’s Model
Initial Exposure
Sight of
needle, taste
of beer, etc.
Neutral Stimuli
Later Effects
Sight of drugassociated
stimuli
CS
Effects of
drug on
neurons
Compensatory
reaction
opposing drug
effects
UCS
UCR
Compensatory
reactions. Resemble
withdrawal effects in
the absence of the
drug.
CR
Siegel, Hinson, Krank, & McCully
(1982)
 In this experiment laboratory rats were
preconditioned to a tolerance of large doses of
heroin…

Procedure:
 Lab
rats given daily intravenous injections for 30 days
 Placebo or heroin given either in “animal colony” or alone
in “white noise” room on alternate days
 Counterbalance of treatment:



For some rats: heroin in WN; placebo in AC
For others: heroin in AC; placebo in WN
Control group received only placebo in different rooms on
alternate days
So this then gives us 3 main
Groups:
 Group 1:
 Received heroin in the Colony room (their normal living quarters)
and placebo in the Noisy room the next day
 Group 2:
 Received placebo in the Colony room (their normal living quarters)
and heroin in the Noisy room the next day
 Group 3:
 Received placebo in the Colony room (their normal living quarters)
and placebo in the Noisy room the next day
 All rats were then injected with a large dose of heroin (15
mg/kg)
But does it depend on the
room???
 But the room in which this potentially lethal dose of heroin was
administered was varied between subgroups of rats…






Group 1A were injected with heroin in the Colony room - where they
had received all their previous injections of heroin
Group 1B were injected with heroin in the Noisy room - where they
had never received any previous injections of heroin
Group 2A were injected with heroin in the Noisy room - where they
had received all their previous injections of heroin
Group 2B were injected with heroin in the Colony room - where they
had never received any previous injections of heroin
Group 3A were injected with heroin in the Colony room - they had
no previous injections of heroin
Group 3B were injected with heroin in the Noisy room - they had no
previous injections of heroin
Results: Death Rate
 Group 3 showed substantial
mortality (96%)
 A group with prior exposure in
the same cage showed
tolerance (only 32% died)
 A group with the same history
of exposure, but tested in an
environment not previously
associated with heroin showed
higher mortality (64%)
Results: Death Rate
 Results:
50% increase in death rate in new room
 Rats show "room-specific" tolerance


Information contained on slides #36-39 taken from following website:


http://salmon.psy.plym.ac.uk/year3/DrugAbuse/drugtolerance.htm
Slide # 35 prepared by Keith Clements and taken from his website:

http://ibs.derby.ac.uk/~keith/b&b/tolerance.ppt