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General Psychology 1
Learning: Classical Conditioning – Module 20
March 17, 2005Class #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 ConditioningExtinction
UCS ---------------------------------------------- UCR NS ----------------------------------------------- NO RESPONSE
NS + UCS -------------------------------------- UCR*Repeated several timesCS ------------------------------------------------ CR
Extinction process is initiated:
CS ----------------------------------------------- CRCS ----------------------------------------------- CRCS ----------------------------------------------- CRCS ----------------------------------------------- CR
Eventually we get………..
NS --------------------------------------------- NO RESPONSE (tone) (no salivation)
Classical Conditioning:Reconditioning
Quick relearning of conditioned response after the extinction trials
Classical ConditioningReconditioning
UCS ----------------------------------------------------- UCRNS ------------------------------------------------------ NO RESPONSE NS + UCS --------------------------------------------- UCR
* Repeated several times
CS ------------------------------------------------------ CRCS ------------------------------------------------------ CRCS ------------------------------------------------------ CRCS ------------------------------------------------------ CR
NS ----------------------------------------------------- NO RESPONSE
Reconditioning process is initiated:
NS + UCS -------------------------------------------- UCRCS ----------------------------------------------------- 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) (salivation)* Repeated several times
NS + UCS ------------------------------------- UCR(medium tone) (food) (salivation)*Repeated several times
NS + UCS ------------------------------------- UCR(high tone) (food) (salivation)* Repeated several times
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 ConditioningDiscrimination
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) UCR (salivation)NS1 (Tone) NO RESPONSE NS1+ UCS (Tone/Food) UCR (salivation)
* Repeated several timesCS (Tone) CR (salivation)
Phase 2:NS2/CS (Light/Tone) CR (salivation)
* Repeated several times
Phase 3:NS2 (Light) What do you think
happens?
Second-order conditioning
Here’s a summary of previous slide:
Phase 1 Phase 2 Phase 3
Tone Food Light Tone Light
(salivation) (salivation) (?????)
Here, a CS that has previously been conditioned is now used to condition another NS
Rescorla (1987): Second-order conditioning
Phase 1:UCS (Food) UCR (salivation)NS NO RESPONSE NS + UCS (Tone/Food) UCR (salivation)* Repeated several timesCS (Tone) 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 Phase 2 Phase 3
Tone Food Food (Poison) Tone
(salivation) (salivation) (?????)
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
Effects of drug on neurons
UCS
Compensatory reaction opposing drug effects
UCR
Later Effects
Sight of drug-associated stimuli
CS
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
