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General Psychology 1

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

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General Psychology 1

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  1. General Psychology 1 Learning: Classical Conditioning – Module 20 March 17, 2005 Class #16

  2. 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

  3. 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

  4. 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

  5. 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

  6. 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

  7. 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

  8. Classical Conditioning • Also, keep in mind the influences of such things as timing, predictability (expectancy), signal strength and attention…

  9. 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

  10. 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.

  11. 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)

  12. Classical Conditioning:Extinction • The decline or disappearance of the CR in the absence of the UCS

  13. Classical ConditioningExtinction UCS ----------------------------------------------UCR NS -----------------------------------------------NO RESPONSE NS + UCS -------------------------------------- UCR *Repeated several times CS ------------------------------------------------CR • Extinction process is initiated: CS ----------------------------------------------- CR CS -----------------------------------------------CR CS -----------------------------------------------CR CS -----------------------------------------------CR • Eventually we get……….. NS ---------------------------------------------NO RESPONSE (tone) (no salivation)

  14. Classical Conditioning:Reconditioning • Quick relearning of conditioned response after the extinction trials

  15. Classical ConditioningReconditioning UCS -----------------------------------------------------UCR NS ------------------------------------------------------NO RESPONSE NS + UCS ---------------------------------------------UCR * Repeated several times CS ------------------------------------------------------ CR CS ------------------------------------------------------ CR CS ------------------------------------------------------ CR CS ------------------------------------------------------ CR NS ----------------------------------------------------- NO RESPONSE • Reconditioning process is initiated: NS + UCS -------------------------------------------- UCR CS ----------------------------------------------------- CR

  16. 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

  17. 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

  18. 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

  19. Classical Conditioning Generalization • CS ---------------------------------------------CR (high tone) (salivation) • CS --------------------------------------------CR (low tone) (salivation) • CS --------------------------------------------CR (medium tone) (salivation)

  20. 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

  21. 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

  22. 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)

  23. Kamin (1969) • Experiment 1: Phase 1 Phase 2 Phase 3 Tone ---- Shock Tone/Light ----Shock Tone---??? Light---???

  24. Kamin (1969) Experiment 2: Phase 1 Phase 2 Phase 3 Eliminated Tone/Light ----Shock Tone---??? Light---???

  25. Classical Conditioning: Second-order conditioning Phase 1: UCS (Food)  UCR (salivation) NS1 (Tone)  NO RESPONSE NS1+ UCS (Tone/Food)  UCR (salivation) * Repeated several times CS (Tone)  CR (salivation) Phase 2: NS2/CS (Light/Tone)  CR (salivation) * Repeated several times Phase 3: NS2 (Light) What do you think happens?

  26. 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

  27. Rescorla (1987):Second-order conditioning Phase 1: UCS (Food)  UCR (salivation) NS  NO RESPONSE NS + UCS (Tone/Food)  UCR (salivation) * Repeated several times CS (Tone)  CR (salivation) Phase 2: UCS (Food/Poison)  CR (salivation) Phase 3: CS (Tone)What do you think happens?

  28. 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???

  29. 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

  30. Drug Tolerance • Siegel et al. (1982) • Demonstrated that classical conditioning principles might be in effect during drug-injecting episodes… • Possible reason for overdoses???

  31. 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)

  32. 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

  33. Compensatory reaction opposing drug effects UCR Effects of drug on neurons UCS Compensatory reactions. Resemble withdrawal effects in the absence of the drug. CR Siegel’s Model Initial Exposure Sight of needle, taste of beer, etc. Neutral Stimuli Later Effects Sight of drug-associated stimuli CS

  34. 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

  35. 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)

  36. 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

  37. 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%)

  38. 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

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