1 / 35

Classical Conditioning II

Classical Conditioning II. What are the necessary conditions for classical conditioning?. Delay. CS. US. Weaker conditioned responding. Trace. CS. US. Explicitly Unpaired. minutes. CS. CS. US. Is contiguity necessary?. Conditioned taste aversion methodology. Distinctive flavor.

caressa
Télécharger la présentation

Classical Conditioning II

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Classical Conditioning II

  2. What are the necessary conditions for classical conditioning?

  3. Delay CS US Weaker conditioned responding Trace CS US Explicitly Unpaired minutes CS CS US

  4. Is contiguity necessary?

  5. Conditioned taste aversion methodology Distinctive flavor LiCl injection

  6. Choice Test ? vs

  7. Is contiguity sufficient?

  8. CS-US belongingness From Garcia & Koelling, 1966

  9. Conclusion thus far: • Forward pairings (contiguity) neither necessary nor sufficient. • Something more is required • Belongingness • Kamin: Surprise

  10. Leon Kamin: Blocking US has to be “surprising” to the animal for learning of the CS-US association to occur. Group Phase 1 Phase 2 Test Block AUS AXUS X? Control BUS AXUS X? Because A already predicts the US in the Blocking group, the US is not surprising during Phase 2 trials.

  11. Conclusion thus far: • Forward pairings (contiguity) neither necessary nor sufficient. • Something more is required • Belongingness • Kamin: Surprise • Relative salience

  12. Salience effects Overshadowing – in compound conditioning, the more salient CS wins Group Treatment Test x Overshadow Ax+ cr Control x+ CR

  13. Conclusion thus far: • Forward pairings (contiguity) neither necessary nor sufficient. • Something more is required • Belongingness • Kamin: Surprise • Contingency • Relative salience • Contingency

  14. CS US CS US Rescorla’s contingency experiment Correlated Group Rate of US Occurrence: 0.1US/sec during CS; 0US/sec outside of CS Uncorrelated Group Rate of US Occurrence: 0.1US/sec during CS; 0.1US/sec outside of CS

  15. Rescorla’s contingency experiment CS Correlated Group US Rate of US Occurrence: 0.1US/sec during CS; 0US/sec outside of CS CS Uncorrelated Group US Rate of US Occurrence: 0.1US/sec during CS; 0.1US/sec outside of CS

  16. CS US CS US Rescorla’s contingency experiment Correlated Group Uncorrelated Group P (US|CS) = 0.5 P(US|noCS) = 0.5

  17. P(US | CS) P(US | ~CS))

  18. P(US | CS) = .4 for all groups CR 0 .1 .2 .4 P(US | noCS) Results of Rescorla’s (1968) Contingency Experiment

  19. It’s a little like… Animals are scientists, trying to make causal predictions. …trying to determine whether the US is contingent on the CS

  20. Other Contingency Phenomena US preexposure effect: Presenting the US repeatedly prior to CS-US trials retards acquisition. CS preexposure effect: Presenting the CS repeatedly prior to CS-US trials retards acquisition. (a.k.a. Latent Inhibition)

  21. US and CS preexposure designs US preexposure Group Phase 1 Phase 2 Test CS Experimental US CSUS cr Control ---- CSUS CR CS preexposure Group Phase 1 Phase 2 Test CS Experimental CS- CSUS cr Control ---- CSUS CR

  22. Factors That Affect Conditioning Contiguity: The closer two stimuli are in space and time, the stronger can be the association between them. “Belongingness”: The “fit” between CS and US Contingency: “Information value.” The higher the correlation between two stimuli, the stronger the conditioned response. Salience: More intense or noticeable stimuli condition more rapidly.

  23. Other conditioning phenomena discovered by Pavlov Conditioned inhibition: A stimulus predicts the absence of the US. Second-order conditioning: Pairing a neutral stimulus with a CS confers associative strength upon the neutral stimulus

  24. X A A A A A A US US US US US US A X A X A Conditioned Inhibition

  25. Second-Order Conditioning • A+/AX- training. Look familiar? • However, number of AX- trials is critical • Few AX- trials leads to SOC • Many AX- trials leads to conditioned inhibition • also, SOC typically produced in two phases. • - A+ training followed by AX+ training.

  26. Design of Conditioned Inhibition Phase 1 Test X A+/AX- CI (Many AX- trials -- tens to hundreds) Design of Second-Order Conditioning Phase 1 Phase 2 Test X A+ AX- CR (Few AX- trials -- typically not more than 8-10)

  27. Classical Conditioning Simulator

  28. The Rescorla-Wagner Model (1972) ∆VCS = αβ(λ-VSUM) ∆VCS = change in associative strength of CS VCS = associative strength of CS λ = Asymptote of learning Learning rate parameters α = CS salience (0-1; 0 = no CS) β = US salience (0-1; 0 = no US)

  29. Phase 2 Group Ph. 1 Ph. 2 λ VA Block A+AX+ 1 1 Acq B+ AX+ 1 0 R-W and Blocking ∆VCS = αβ(λ-VSUM) Blocking group ∆VX = αβ(λ -VA+X) ∆VX = 1(1 –[1+0]) = 0 Acq group ∆VX = αβ(λ -VA+X) ∆VX = 1(1 – [0+0]) = 0

  30. Rescorla-Wagner Spreadsheet

  31. R-W model accounts for: Blocking (Kamin) Overshadowing (Pavlov) Ax+, A-US association develops faster than X-US CSs have unequal learning rate parameters. Conditioned inhibition (Pavlov) A+/AX-, (λ-VA+X) = (0-[1+0]) = -1 X develops negative associative strength!

  32. Overexpectation Effect Group Ph. 1 Ph. 2 Test X Experimental A+/X+ AX+ cr Control A+/X+ --- CR

  33. CS CS US US UR UR What is learned in CC? Clark Hull (S-R theory) Pavlov (S-S theory)

  34. Test – Devaluation Experiment Holland & Straub (1979) Train Devaluation Test TonePellet PelletRotation ToneCR Pellet | Rotation Tone CR

More Related