Chapter 3: Classical Conditioning

1. PSY 445: Learning & Memory Chapter 3: Classical Conditioning

2. Pavlovian Conditioning • Pavlov was a research physiologist, not a psychologist • At age 33, earns MD • Spends next 20 years studying the digestive system • Russia’s first Nobel Prize winner in 1904 • Novel work done over the final 30 years of his life that earns him his place in scientific history Ivan Pavlov (1849-1936)

3. Definition of Classical Conditioning • In classical conditioning, the organism learns a connection between two stimuli • In other words, the organism learns that one stimulus predicts another stimulus • Aform of associative learning • Learning in which connections are formed between internal representations of events (e.g., stimuli and responses) during learning. • Procedure • Classical conditioning is the presentation of two or more events in an experimentally determined temporal relationship • Any change in responding to one of the events is seen as evidence of a learned association

4. Definition of Classical Conditioning • Unconditioned stimulus (US) • In classical conditioning, this is the stimulus that elicits the unconditioned response (UR) without conditioning • 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 (UR) • 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

5. Pavlov’s Paradigm Pavlov’s Participants 

6. Methods of Studying Classical Conditioning Eyeblink Conditioning Skin Conductance Response Conditioned Taste Aversion Evaluative Conditioning

7. Eyeblink Conditioning The procedure is relatively simple and usually consists of pairing an auditory or visual stimulus (CS) with an eyeblink-eliciting US • For example, light might be paired with a mild puff of air to the cornea or a mild shock After many CS-US pairings, an association is formed such that a learned blink, CR, occurs and precedes US onset • The magnitude of learning is generally gauged by the percentage of all paired CS-US trials that result in a CR In this video clip, experimenter paired puff of air with pencil tap 

8. Skin Conductance Response (SCR) • Electrodes put on the arm or palm • A loud unexpected noise or mild shock (US) will usually cause this response (OR) • Soft tone or light may be presented before the US • Several pairings • Just the tone or light (CS) will produce the SCR (CR) Electrodes will be put on participants prior to presentation of CS-US pairings 

9. Conditioned Taste Aversion Typical Procedure • Rats are given novel taste (saccharin-flavored water) is followed by an illness-producing drug • Gastrointestinal distress • Flavored water is again presented Typical Results • Decrease or complete avoidance of the flavored water (CS)

10. Evaluative Conditioning Achange in liking, which occurs due to an association with a positive or negative stimulus • Neutral stimulus is paired with something one likes or dislikes • Is not reflex-evoking After these movies came out in 1980s, the hockey mask was never the same 

11. Evaluative Conditioning Typical Procedure • An affectively neutral stimulus is presented along with another stimulus that already evokes some type of affective evaluation • For example, a word (NS) is paired with an bad odor (US) Typical Results • Emotional tone of the neutral stimulus will change to correspond to the US • The word (CS) will come to evoke a negative feeling (CR) from the person who has gone through this type of conditioning

12. Evaluative Conditioning Hammerl, Bloch, & Silverthorne (1997) Procedure • Scenic pictures were pre-rated • Pictures that were originally rated as neutral (NS) were then paired (five trials) with either pictures that were rated low or rated high (US) Results • When paired with the high-ranked pictures, the neutral pictures received more positive ratings then before; when paired with the low-ranking pictures they received less positive ratings then before • Thus, the originally neutral pictures become the CS and the resultant ratings of these pictures become the CR

13. Evaluative Conditioning • Limitations • Doesn’t fit classical conditioning pardigm completely • Reliance just on verbal reports is questionable • Some believe the changed preferences are based on conscious knowledge; not automatic responses

14. What stimuli can serve as CSs? Exteroceptive Stimuli • Stimuli involving events outside the body that stimulate the sensory receptors • Examples of exteroceptive stimuli include sounds, sights, smells, touch sensations, tastes, and the like Interoceptive Stimuli • Stimuli inside the body that reflect some change in an internal state • Examples of interoceptive stimuli include body sensations such as a full bladder or empty stomach

15. What stimuli can serve as CSs? • Contextual Stimuli • The place or environment where training occurs are readily conditioned • Fear of dentist’s office • Temporal Stimuli • The passage of time since the last US serves as the CS for the next US • Marquis (1941) delayed feeding of infants from usual 3-hour interval • Circadian Stimuli • Conditioning of time of day can lead to different CRs

16. What stimuli can serve as USs? • Stimuli that have either biological significance or acquired significance work effectively as a US

17. Basic Phenomena of Conditioning • Acquisition • Extinction • Spontaneous Recovery • Generalization • Discrimination

18. Basic Phenomena of Conditioning Acquisition • When the organism first learns the connection between the CS and the US, it is said to be in the stage of acquisition • The initial gain in response strength is large on each trial, and then it levels out at the end of the acquisition period. See graph 

19. Basic Phenomena of Conditioning Acquisition • Control Procedures – its important to employ these conditions to protect against confounding variables Unpaired Control • Experimental group gets paired CS-US; control gets CS and US separately Truly Random Control • CS and US are each separately programmed to occur randomly in time during the experimental sessions along with the usual pairing of CS-US

20. Basic Phenomena of Conditioning • Extinction • The decline or disappearance of the CR in the absence of the US • Presentation of CS alone

21. Basic Phenomena of Conditioning: Extinction US ----------------------------------------------UR NS -----------------------------------------------NO RESPONSE NS + US -------------------------------------- UR * This is repeated several times CS ------------------------------------------------CR • Extinction process is initiated: CS ----------------------------------------------- CR CS -----------------------------------------------CR (less response than before) CS -----------------------------------------------CR (less response than before) CS -----------------------------------------------CR (less response than before) • Eventually we get……….. NS ---------------------------------------------NO RESPONSE (bell) (no salivation)

22. Basic Phenomena of 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 • Apparently, extinction does not eliminate the CS-US association; just suppresses it Trial 11 represents a two-week rest period 

23. Spontaneous Recovery What happens next? Extinction continues CS-US pairing

24. Basic Phenomena of Conditioning Generalization • After a CR is acquired, stimuli that are similar but not identical to the CS also will elicit the response • The greater the similarity between a new stimulus and the CS the stronger the CR will be • Conditioned to tone of F 

25. Basic Phenomena of ConditioningDiscrimination • Organisms can be conditioned to learn to differentiate among similar stimuli • Even a similar tone will not produce a response in certain situations • For instance, if two tones are continuously presented but only Tone 1 is paired with the US then CR will only appear when Tone 1 is presented

26. The Role of Contiguity This is the belief that the critical factor in determining whether or not classical conditioning would occur was timing • The most important thing to control in a classical conditioning experiment was that the CS and the US should be close together in time

27. Does the sequence matter? • Forward Pairing • CS-US • Strong conditioning • Simultaneous Pairing • CS/US • No conditioning • Backward Pairing • US-CS • Weak conditioning

28. Other factors effecting conditioning • Prior Exposure • Latent inhibition reduces conditioning effect • Compound CSs • Usually weaker conditioning to two CSs conditioned together than when done one at a time • Surprise • The Blocking Effect See next slide 

29. The Blocking Effect Kamin (1969) • Experiment 1: Phase 1 Phase 2 Phase 3 Tone ---- Shock Tone/Light ----Shock AM: Tone---? * This is repeated several times PM: Light---?

30. Rescorla-Wagner Model This model explains the Blocking Effect

31. Other factors effecting conditioning CS-US Relevance • Belongingness – the idea that certain CSs and USs seem to belong together

32. Belongingness Procedure • Rats drink flavored water from tubes that flashed light and made noise when the tubes were licked… • Group 1: • Rats were given electric shocks to their feet two seconds after beginning to drink • Group 2: • Rats were exposed to X rays (which made them sick) while they drank • Later, both groups were tested with: • A tube of unflavored water producing lights and noise • A tube of flavored water that was not producing lights and noise • Rats are basically given a choice between these two tubes to drink from Garcia & Koelling (1966)

33. Belongingness Garcia & Koelling (1966) Results • Group 1 (rats that had been shocked) avoided the tube producing the lights and noise while Group 2 (rats that had been made sick) avoided only the flavored water Interpretation • Evidently, rats (and other species) have a built-in predisposition to associate illness mostly with what they have eaten or drunk (Group 2 rats) and to associate skin pain mostly with what they have seen or heard (Group 1 rats) • This is an example of preparedness

34. Conditioned Inhibition A CS becomes associated with the absence of the US • For example, knowing when food is NOT available

35. Second-Order Conditioning A new NS can become a new CS

36. Sensory Preconditioning • Two CSs are paired in first phase with no US • For example, tone and light • One of the CSs is paired with food in the second phase • For example, tone and food • In third phase, the other CS (the one never paired with the US) is tested • For example, light • CR is witnessed

37. Difference between higher order and sensory preconditioning The difference is when the two CSs are paired • In higher-order conditioning, the CS2-CS1 pairing happens AFTER the US has been paired with the CS1 • In sensory preconditioning, the CS2-CS1pairing happens BEFORE the US has been paired with the CS1

38. Preparatory Response A theory of learning that a different form of conditioning, instrumental conditioning, controls the acquisition and performance of conditioned responses • CR are rewarded (a reinforcement theory)

39. Learning in the Brain Cerebellum appears to have the key function related to the conditioning process • Considered the final destination for association to take place • Lesions in this area of the brain prevent tone-to-eyeblink conditioning

40. The Role of Awareness in Conditioning • Early Pavlovian ideas would say awareness was not necessary for conditioning • Automatic processes • Conflicting studies • Some reports of CS-US contingency suggest that awareness can be a factor • Secondary tasks are often employed • Sometimes participants in these experiments report they are aware of CS-US connections • But this does not correlate with the conditioning that is actually taking place

41. Extensions of Conditioning 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

42. Extensions of Conditioning Siegel, Hinson, Krank, & McCully (1982) • Demonstrated that classical conditioning principles might be in effect during drug-injecting episodes • Possible reason for overdoses?

43. Extensions of Conditioning Siegel’s theory… • US ----------------------------------------------UR (drug) (anti-drug defenses) • NS -----------------------------------------------NO RESPONSE (injection ritual) (no defenses) • NS + US --------------------------------------UR (injection ritual) + (drug) (anti-drug defenses) * Repeated several times • CS -----------------------------------------------CR (injection ritual) (anti-drug defenses) Siegel et al. (1982)

44. Extensions of Conditioning • 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 et al. (1982)

45. Extensions of Conditioning • 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 Siegel et al. (1982)

46. 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) Siegel et al. (1982)

47. 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… • On Day 31: • Group 1Awere 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 • Where they had no previous injections of heroin • Group 3B were injected with heroin in the Noisy room • Where they had no previous injections of heroin Siegel et al. (1982)

48. 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%) Siegel et al. (1982)

49. Results: Death Rate • Results • 50% increase in death rate in new room • Rats show "room-specific" tolerance • Siegel (1984) • In a follow-up study, overdose victims who had survived were interviewed and 70% reported they had changed environmental conditions Siegel et al. (1982)

50. Conditioning with Drug USs Siegel (1991) • Reviewed studies that tested conditioning after drug exposure by replacing the drug with a placebo injection • Monitoring of body’s conditioned response to the injection procedure (CS) in the absence of the drug (US) • Physiological reactions are sometimes opposite of what you would expect from receiving the drug • For example, morphine raises body temperature, placebo lowers it; morphine reduces pain, placebo increases pain sensitivity • This leads to speculation that conditioning can lead to the development of conditioned responses that are the opposite of unconditioned responses