Chapter 3

1. Chapter 3 Classical Conditioning

2. Ivan Petrovich Pavlov (1849-1936) • Classical (Pavlovian) conditioning • Medical physiologist • Digestion • Human/animal differences • Conditioned reflexes en.wikipedia.org/wiki/File:Ivan_Pavlov_(Nobel).png en.wikipedia.org/wiki/File:One_of_Pavlov%27s_dogs.jpg

3. Terminology • Unconditional stimulus (US) • Stimulus that elicits the innate reflex (e.g., food) • Unconditional response (UR) • Reflex action that occurs in response to US (e.g., salivation) • Conditional stimulus (CS) • Any stimulus that doesn’t originally elicit the UR (e.g., bell) • Conditional response (CR) • The action elicited by the CS (e.g., salivation)

4. Conditioning and Awareness • Awareness of conditioning not required for learning

5. Innate • US-UR is an innate stimulus-behaviour • “Reflex” • Hardwired • Stereotypic pattern of behaviour

6. Later Trials First Few Trials CS CS US US UR CR UR Time Example: Bell and Food CS = bell US = food UR = salivation CR = salivation

7. Processes • Acquisition • Acquiring a CR • E.g., pair CS with US • Extinction • Reduce/eliminate a CR • E.g., present CS without US

8. Measuring Conditioning • Sometimes difficult to measure CR • e.g., if CS & US close together, CR & UR can overlap • Test trial (probe trial) • Give CS alone • Intensity • Does CR intensity increase with experience?

9. UR (blink) US (airpuff) CR (blink) Example: Eyeblink Conditioning CS (tone) • Airpuff on eye • Blink • UR vs. CR eyeblinks • UR blink faster than CR blink

10. Example: Taste Aversion • Very strong • Very persistent • Usually conditioned after one presentation • Experiment • Rats fed novel food (CS) • Injected with lithium chloride (US) • Choice: novel food or regular food • Chose regular food

11. Higher-Order Conditioning • CSs and USs can be associated (First-order) • CSs can be associated with other CSs • Second-order conditioning

12. first-order tone (CS1) food (US) First-Order Conditioning salivation (CR)

13. second-order light (CS2) tone (CS1) tone (CS1) food (US) salivation (CR) Second-Order Conditioning salivation (CR) Risk of extinction?

14. CS+ and CS- • CS+ (excitatory CS) • CS predicts occurrence of US • Activates behaviour related to US • CS- (inhibitory CS) • CS predicts non-occurrence of US • Suppresses behaviour related to US

15. PAVLOV’S PROCEDURE Trial Type A Trial Type B CS+ CS- US • Randomize trial type presentation NEGATIVE CONTINGENCY PROTOCOL CS- US • Context cues serve as CS+

16. CS- produces absence of CR No CR You’ve produced CS- Haven’t learned anything How to measure nothing… Summation test Measure CR with CS+ Compound stimulus of CS+ & CS-; measure CR Retardation of acquisition Trained CS- and novel stimulus; pair both with novel US for same number of trials Measure CR for both Prior learning of CS- inhibits learning new association Testing for CS-

17. or Short Delay Conditioning • Strongest and most rapid • Simple autonomic responses: 5-30 seconds • Quick skeletal responses: 0.5 seconds CS US

18. or Long Delay Conditioning • Other distracting stimuli? • Timing estimation required CS US

19. trace interval Trace Conditioning • From “memory trace” • Must remember CS • Other stimuli interfere CS US

20. Simultaneous Conditioning • Weaker than short delay • CS can’t signal onset of US • Not predictive CS US

21. Backward Conditioning • Ignores order; US comes first • CS has no predictiveness • Might become CS- CS US

22. Influences in Classical Conditioning

23. CS-US Contiguity • Closeness together in time and/or space • Usually, more learning if greater contiguity between CS & US • Type of conditioning may influence this • e.g., eyeblink vs. taste aversion

24. CS-US Contingency • If-then situation • X iff Y • Consistency of pairing CS and US • Greater contingency, greater learning

25. Stimulus Features • Nature of stimulus affects its conditioning ability • Intensity • Novelty

26. Compound Stimuli • Two+ simple CSs presented at the same time • Paired with US

27. Overshadowing • Salience • Exclusive regulation of CR by most salient CS in compound stimuli

28. Latent Inhibition • Repeatedly present neutral stimulus (N) • Pair N with US • Harder to condition N as CS • CS- or habituation

29. Blocking • CS1 -- US • CS1 and novel stimulus (CS2) with US • CS1 --> CR • CS2 --> no or very weak CR

30. Textbook Error: p. 77 • “But suppose we eat two foods, one spicy and the other bland. If we then become sick, thanks to blocking we are likely to develop an aversion to the spicy food -- even though it may have been the bland food that caused our illness.”

31. Sensory Preconditioing • Pair two neutral stimuli repeatedly • Pair one with US repeatedly until CR produced • Test other stimulus • CR produced

32. Number of CS-US Pairings • Acquisition curve • Non-linear • Asymptote asymptote CR Strength Conditioning Trials

33. Intertrial Interval • ITI • Time between each CS-US pairing (i.e., between trials) • Generally, around 30 seconds effective

34. Extinction of CR

35. Extinction • CS without US --> Extinction • Weakening and stopping of CR • Not forgetting • A type of conditioning • CS paired with absence of US

36. Spontaneous Recovery • After extinction, let time pass • Present CS again (no US) • Temporary, small return of CR • Shows extinction is not forgetting

37. Relearning/Reacquisition Effect • Extinguish CR • Recondition with CS-US pairing • Fewer trials required

38. Spontaneous Recovery Reacquisition Acquisition Extinction Putting it Together Strength of CR CS&US CS alone CS alone CS&US Trials/Time

39. Theories of Classical Conditioning Associationism, Stimulus Substitution, Preparedness, Rescorla-Wagner

40. Associationism • Linking together of: • Events • Memories • Actions and consequences • Contiguity, similarity, contrast • Central to study of learning and behaviour

41. Ebbinghaus’ Memory Experiments • 1880s • Nonsense syllables • E.g., ZOG, PAF, TOB • One subject • Recite from memory • Savings • E.g., if 10 trials initially, then after a delay 3 more trials, savings = (10-3)/10 = 7/10 = 70%

42. 100 75 Percent Savings 50 25 20min 1hr 8.8hr 1day 2days 6days 31days Time between study and relearning Major Findings Forgetting Curve • List length • Effects of repetition • Overlearning • Effects of time • Role of contiguity • Backwards associations

43. Classical Conditioning • Innate US-UR reflex pathway • CS is associated with the US • Through the associative process, CR is produced

44. Stimulus Substitution Theory • Pavlov • CR and UR produced by same neural region • CS takes on properties of US • Substitution • CR should be the same as UR

45. Example: Sign Tracking • Response not required • US often food • Stimulus (CS) indicates US availability • Subject “tracks” the sign more and more • CS takes on properties of US • Pigeon autoshaping • Longbox autoshaping F = CS F = US

46. Biological Predispositions Burns & Domjan (2000) Timberlake & Grant (1975)

47. Problems with SST • CS not a complete substitute for US • e.g., eyeblink differences • Magnitudes • CSs produce different responses • Omissions and additions • Compensatory conditional responses

48. Preparatory Response Theory • Learn responses that prepare organism for US occurrence • Sometimes CR same as UR, sometimes different

49. Example: Drug Tolerance • Neurophysiological dependencies • Siegel (1975) • Contextual stimuli act as CSs • Compensatory CR • Morphine

50. Contextual Stimuli Theory • Rats on hotplate • Between-groups study • Independent variables: • Morphine or placebo • Location of injection (Home or Injection room) • Dependent variable: time to lift feet