CHAPTER 6

1. CHAPTER 6 Pavlovian Conditioning: Storage and Response Output

2. WHAT IS LEARNED IN CONDITIONING? • Dog receives Pavlovian training trials. • E.g., tone CS paired with food US. • Dog now salivates to tone. • What does dog learn? • How is dog changed?

3. Two Possibilities: • Dog associates CS with UR: tone with salivation. • Dog associates CS with US: tone with food.

4. S-R Learning: CS US UR

5. S-S Learning: CS US UR

6. Is Learning S-S or S-R? • Evidence supports both S-R and S-S views of conditioning process. • We cannot now resolve the issue. • But, we can discuss evidence that has accumulated to support each view.

7. Paradigms to Distinguish S-S from S-R Learning • Sensory Preconditioning • Second-Order Conditioning • US Devaluation

8. Sensory Preconditioning • Dog receives trials in which buzzer is paired with light. • No food USs are presented. • After initial training, light is paired with food, which produces salivation. • After a number of trials, light comes to elicit anticipatory salivation. • Finally, buzzer is sounded. • Buzzer alone elicits salivation.

9. Sensory Preconditioning • Phenomenon is called sensory preconditioning. • Sensory conditioning (between CSs, like buzzer and light) occurs prior to any conditioning of either CS with US. • Looks like S-S learning. • No salivation response is elicited during pairing of buzzer and light.

10. Sensory Preconditioning • Steps in sensory preconditioning: • CS2CS1 • CS1US • CS2CR?

11. Second-Order Conditioning • Light is paired with food, which produces salivation. • After a number of trials, light comes to elicit anticipatory salivation. • Dog now receives trials in which buzzer is paired with light. • No food USs are presented. • Buzzer alone elicits salivation.

12. Second-Order Conditioning • Steps in second-order conditioning: • CS1US • CS2CS1 • CS2CR?

13. Sensory Preconditioning vs Second-Order Conditioning • Steps in sensory preconditioning: • CS2CS1 • CS1US • CS2CR? • Steps in second-order conditioning: • CS1US • CS2CS1 • CS2CR?

14. CS1 UR1 US1 CS2 CR1 CS1 CS1 UR2 US2 S-R Learning: Special Predictions CS2CR1

15. CS1 UR1 US1 CS2 CR1 CS1 CS1 UR2 US2 S-S Learning: Special Predictions CS2CR2

16. Second-Order Conditioning: A Special Test • Light is paired with food. • After a number of trials, light comes to elicit anticipatory salivation. • Dog now receives trials in which buzzer is paired with light. • Buzzer alone elicits salivation. • Light is finally paired with foot shock, which elicits leg flexion. • What does buzzer alone produce? • Salivation: S-R learning.

17. Second-Order Conditioning: An Autoshaping Test • If pigeons receive tone-food pairings, then they show no sign of conditioning to tone. • Pigeons do not approach and peck at sound source in same way they approach and peck at key light CS paired with food. • Yet, if pigeons later receive second-order conditioning trials of key light followed by tone, then they start key pecking. • So, tone CS can be used as a US to produce Pavlovian key pecking.

18. Second-Order Conditioning: An Autoshaping Test • Result indicates that, during tone-food pairings, pigeons do form an association, so that tone evokes a representation of food. • When key light is later paired with tone, it is paired with representation of food produced by tone. • Conditioned key pecking results, even though key light and food (or pecking) have never themselves been paired: S-S learning.

19. US Devaluation • CS-US pairings • CS?CR • US devaluation • CS?CR • Reduced CRs after US devaluation imply S-S learning.

20. US Devaluation • Conditioning involves association between representations of CS and US. • Initially, US is represented as potent, so strong conditioned responding occurs. • Then, US is devalued and new representation of less potent US is formed. • When CS is later presented, it activates this less potent representation. • Result is weaker conditioned responding.

21. Aversive US Devaluation • CS-US (noise) pairings • CSfear • US devaluation (habituation to noise) • CSreduced fear

22. Appetitive US Devaluation • CS-US (food) pairings • CSsalivation • US devaluation (satiation to food) • CSreduced salivation

23. Is Learning S-S or S-R? • Organisms can learn both types of associations. • Processes of association formation are more varied and flexible than Pavlov might have imagined. • Conclusion holds for both excitatory and inhibitory conditioning.

24. ADAPTIVE FUNCTION OF CONDITIONED RESPONSE • What determines kinds of CRs that pairings of CSs and USs will produce? • In studies of Pavlovian conditioning, one cannot arbitrarily choose CRs. • Pavlov believed CR resembled UR. • So, if food produces salivation, then CS too should produce salivation. • If shock increases heart rate, then CS too should increase heart rate.

25. ADAPTIVE FUNCTION OF CONDITIONED RESPONSE • Later research suggests that CR determination is not so simple. • Although CRs sometimes mimic URs, they often do not. • Form of CRs can be influenced by many factors.

26. ADAPTIVE FUNCTION OF CONDITIONED RESPONSE • In last 20 years, considerable work has been done on nature of Pavlovian CRs. • At present, no single, general principle can account for all findings. • But, while seeking such a general principle, researchers have discovered many extremely exciting phenomena.

27. ADAPTIVE FUNCTION OF CONDITIONED RESPONSE • Phenomena suggest that CRs take a form that serves organism’s needs. • CRs help organisms adapt to whatever challenge US poses. • Sometimes, it is adaptive for CRs to resemble URs. • But, it may be more adaptive for CRs to be different from URs. • Indeed, it is sometimes adaptive for CRs to be the opposite of URs.

28. ADAPTIVE FUNCTION OF CONDITIONED RESPONSE • Would Pavlovian conditioning have evolved if it did not importantly contribute to organism’s well-being? • Probably not. • What might that contribution be? • It allows organisms to anticipate and respond to upcoming events of importance like food or danger. • Pavlov called this “signalization.”

29. ADAPTIVE FUNCTION OF CONDITIONED RESPONSE • Whether such anticipation truly helps survival depends on what organism does when Pavlovian CSs occur. • If organism learns that a tone reliably precedes shock, but it does nothing with that information, then Pavlovian conditioning would be useless. • But, organisms not only learn Pavlovian CS-US relations, they develop CRs that do have adaptive consequences.

30. ADAPTIVE CONDITIONED RESPONSES: EXAMPLES • Take study of conditioned salivation. • Saliva begins digestive process. • Ordinarily, food in mouth triggers salivation. • But, digestion is facilitated if saliva is already present before food is ingested. • Conditioned salivation produces this beneficial result.

31. ADAPTIVE CONDITIONED RESPONSES: EXAMPLES • Take study of conditioned sexual arousal. • Male rats could mate with receptive females. • In some cases, copulation was preceded by distinctive CSs; in other cases, it was not. • CSs facilitated sexual performance by shortening male’s latency to copulate and by decreasing male’s time to ejaculate. • Adaptiveness of speeding up reproduction is obvious when one considers how vulnerable to predation rats are while mating.

32. ADAPTIVE CONDITIONED RESPONSES: EXAMPLES • Take study of release of brain chemicals called endorphins. • Endorphins are endogenous morphine-like substances that work like morphine to reduce sensitivity to pain. • When animals are exposed to Pavlovian conditioning with shock US, their sensitivity to shock decreases in CS. • CS appears to trigger endorphin release.

33. CRs THAT OPPOSE URs • Data for adaptiveness of CRs also comes from cases where CR is opposite of UR. • Typical UR to shock is increase in heart rate. • Increased heart rate is useful because it is part of a general arousal state that mobilizes responses to danger. • But, CR to CS for shock is a decrease in heart rate. Antagonistic CR may be useful by reducing physiological damage produced by long periods of high cardiovascular output.

34. CRs THAT OPPOSE URs • A dramatic example of CR-UR antagonism comes from studies in which morphine is US. • Morphine produces analgesia; it reduces pain sensitivity. • One can measure analgesic effect by placing a rat’s paw on a hotplate and seeing how long it takes for rat to withdraw its paw. • Under influence of morphine analgesia, paw withdrawal is slowed, presumably because morphine makes heat less painful.

35. CRs THAT OPPOSE URs • If injection itself serves as CS and morphine is US, then what is CR to injection? • We test by giving rat an injection of neutral salt water and placing its paw on hotplate. • Conditioned rat removes its paw even faster than rat without morphine conditioning. • After conditioning, heat seems to hurt more to injection procedure alone. • CR to injection is increase in pain sensitivity, whereas UR to morphine is decrease in pain sensitivity.

36. Conditioning and Tolerance • People’s responses to many drugs change as they continue to use them. • A given dose becomes less effective as a person’s experience with it continues. • We say the person has developed tolerance to drug. • To produce an effect of a fixed magnitude, larger doses of drug must be administered.

37. Conditioning and Tolerance • Tolerance has traditionally been considered to result from a physiological process, like habituation. • Although this physiological process may partly account for tolerance, recent studies suggest that tolerance may also result from Pavlovian conditioning. • If Pavlovian CRs grow and are opposite in sign from URs, then net response to morphine injections will become smaller.

38. OPPONENT PROCESS THEORY • Examples of CRs that are opposite of URs prompted a theory of motivation that is quite broad in scope and has been extremely influential. • Opponent process theory. • Details of theory rest on hypothesized states that accompany and follow powerful USs. • Other theories have also been proposed.

39. USING CONDITIONING PRINCIPLES TO TREAT ADDICTION • Regardless of merits of specific theories, conditioning principles can importantly elucidate drug use and abuse. • Specific therapeutic techniques have emanated from Pavlovian laboratories: • Extinction: Repeated presentations of CS without US. • Counterconditioning: Associate US with other, noxious US.

40. Pavlovian CRs: Final Summary • Every instance of Pavlovian conditioning reflects development of an association between CS and some aspect of US. • Discovering laws to describe development of these associations, no matter how they may be shown in behavior, has been of concern to researchers in Pavlovian conditioning.

41. Pavlovian CRs: Final Summary • Nevertheless, understanding translation of learning into performance is also an important objective. • Such understanding may help illuminate adaptive significance of Pavlovian conditioning.