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Facebook Group:. The group is called: Psych281 Spring08 Available only to University of Alberta network Sorry to be rude but… Please don’t add me as a friend (avoiding any kind of favoritism, etc…). Chapter 3 Classical (Pavlovian) Conditioning. Ivan Petrovich Pavlov (1849-1936).

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  1. Facebook Group: • The group is called: • Psych281 Spring08 • Available only to University of Alberta network • Sorry to be rude but… • Please don’t add me as a friend (avoiding any kind of favoritism, etc…)

  2. Chapter 3Classical (Pavlovian) Conditioning

  3. Ivan Petrovich Pavlov (1849-1936) • Pavlovian (Classical) conditioning • Physiologist • Digestion • Dogs • Conditional redirection of reflexes  Conditional reflexes

  4. Conditional?? • Yes, conditional • Mistranslated to conditioned • For learning at least, this is where the term “conditioning” came from

  5. 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., buzzer) • Conditional response (CR) • The action elicited by the CS (e.g., salivation) • THIS IS LEARNED

  6. The Basics • Use behaviours that are already in place – Reflexes • Associate some new (neutral) stimulus with the stimulus that evokes the reflex • How? Present them together! • Buzzer-food (salivate) • Buzzer-food (salivate) • Buzzer-food (salivate) • Buzzer-? - CS-US  UR - CS-US  (CR) UR - CS-US  (CR) UR - CS  CR

  7. The Basics TIME on Conditional Stimulus off on Unconditional Stimulus off (after enough pairings) Conditional Response Unconditional Response

  8. Measuring Conditioning • Sometimes difficult to measure CR • e.g., if CS & US close together, CR & UR can overlap • Buzzer-food-saliva, buzzer-saliva-food? • How long is the separation between the buzzer and the food? • Intensity • Does CR intensity increase with experience? • Test trial (probe trial) • Give CS alone

  9. Probe (Test) Trials TIME on Conditional Stimulus off on Unconditional Stimulus off Conditional Response? No Unconditional Response without the US!

  10. Some notes & examples… • Awareness is NOT necessary • Eyeblink • Conditioned Suppression (Conditioned Emotional Response) • Suppression ratios • Another way of MEASURING conditioning • Taste Aversion • Tequila?

  11. S-S or S-R? • What kind of connection is being made? Response US CS

  12. Rescorla (1973) • So, how do you get rid of a response that is hard wired to a stimulus? • How can you get rid of a reflex? • Habituation

  13. Results • Less suppression in Habituation group • (In other words, more responding) • Therefore, the connection MUST be S – S

  14. second-order CS first-order CS tone (CS1) food (US) Higher Order Conditioning • S-S-S? • CSs and USs can be associated (First-order) • CSs can be associated with other CSs • Second-order conditioning Light (CS2) salivation (CR)

  15. Types of Conditioning

  16. Types of Conditioning • Delay • Short • Long • Trace • Simultaneous • Backwards • Inhibitory

  17. Delay Conditioning • CS and US overlap • Short • Usually the most effective • Long • timing

  18. Trace Condition • From “memory trace” • Must remember CS • Other stimuli interfere CS GAP US

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

  20. Backwards conditioning • Much more difficult • Ignores order CS US

  21. Conditioned Inhibition • CS- • Up until now, we’ve been talking about CS+ • CS signals the ABSENSE or NON-OCCURRENCE of US • Needs to be some expectation of the US for this to work CS- CS+ US

  22. Factors Affecting Conditioning

  23. Factors that affect conditioning • Contiguity • Contingency • Stimulus Features • Prior Experience • Number of Pairings • Intertrial Interval

  24. 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 • BUT, contiguity is not sufficient!

  25. Contingency • If-then situation • Consistency of pairing CS and US • Greater contingency, greater learning • informative

  26. Stimulus Features • Intensity of stimuli (CS & US) • Compound Stimuli • Two+ simple CSs presented at the same time • Paired with US • Overshadowing – if one CS is more salient, the other CS may be ignored • Nature of Stimuli (relevance or belongingness) • Loud & noisy water?

  27. Prior experience • Prior experience with CS and/or US affects conditioning • contingency • Latent inhibition • Prior experience with an neutral stimulus makes it harder for it to become a CS later • Novelty • Blocking • Introducing a new CS (CS2) in compound with an already trained CS (CS1) • CS2 won’t be learned about

  28. Sensory preconditioning • Pair two CSs • Pair one with a US • Unpaired CS still elicits CR • Phase 1 (CS1+CS2): • Light + Tone • Light + Tone • Light + Tone • Phase 2 (CS1+US): • Light + Food • Light + Food • Light + Food • Test (CS2?) • Tone? • (measure response)

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

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

  31. More conditioning stuff… Extinction, Spontaneous Recovery and Reacquisition

  32. Extinction • Continued pairing of CS with US maintains CR • CS without US --> Extinction • Weakening and stopping of CR • Not forgetting • A type of conditioning • Withhold responding • CS paired with absence of US

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

  34. Reacquisition • Extinguish CR • Recondition with CS-US pairing • Fewer trials required

  35. Spontaneous Recovery Reacquisition Acquisition Extinction All Together Now! Strength of CR CS&US CS alone CS alone CS&US Trials/Time

  36. Theories How does this all work?

  37. Stimulus Substitution Theory • Pavlov • CR and UR produced by same neural region • Response center • CS takes on properties of US • Substitution Response center US center CS center

  38. Sign Tracking Food

  39. Sign Tracking

  40. But… • CR should be the same as UR • e.g. signtracking, autoshaping • But it’s NOT!! • Intensity, magnitudes • Omissions & additions • Different CSs elicit different CRs • Compensatory responses

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

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