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Limitations to Classical Conditioning

Overshadowing. When conditioning involves a compound stimulus, one stimulus may acquire more stimulus control than the otherCompound stimulus = at least 2 elements or simple stimuli (e.g., Clicker Flashing Light)The more salient stimulus of a compound is more readily learned, so it will interfer

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Limitations to Classical Conditioning

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    1. Limitations to Classical Conditioning Overshadowing Blocking Latent Inhibition

    2. Overshadowing When conditioning involves a compound stimulus, one stimulus may acquire more stimulus control than the other Compound stimulus = at least 2 elements or simple stimuli (e.g., Clicker + Flashing Light) The more salient stimulus of a compound is more readily learned, so it will interfere with conditioning to the less salient one

    3. Overshadowing Grice & Hunter, 1964 Human eyeblink conditioning 3 Groups: 100 trials w / CS (loud tone) 100 trials w / CS (soft tone) 50 trials w / CS(loud tone) & 50 trials w / CS (soft tone)

    4. Blocking Phase 1: Pair CS1 ? UCS Phase 2: Pair compound stimulus with UCS: CS1CS2 ? UCS Phase 3: Test element stimuli alone to determine amount of conditioning Conditioning to CS1 will be strong, but conditioning to CS2 will be weak: Blocking

    5. Kamin (1968) Acquisition (?Shock) Phase 1 Phase 2 Group 16 Trials 8 Trials NL -- NL N-NL N NL N only N N Test 4 trials Results Nonreinforced Supp. Ratio L .05 L .45 L .44

    6. Contiguity or Contingency? Contiguity = Pair 2 or more stimuli and an association will form Although 2 CSs were both paired with a UCS in the Blocking procedure, no learning occurred to one of the CSs Contingency = when one stimulus is dependent upon another

    7. Contingency p (UCS / CS) + p (UCS / No CS) In other words, a CS is only good as a predictor if the UCS occurs fairly often in the presence of the CS but not very often in its absence

    8. Contingency Kamin’s study: Group N-NL received 24 shocks during acquisition; p(shock / Noise) = 24 / 24 = 1.0 and p(shock / No Noise) = 0 / 24 = 0 Group NL received 8 shocks during acquisition; p(shock / Noise) = 8 / 8 = 1.0 and p(shock / No Noise) = 0 / 8 = 0 N for both groups is a great predictor

    9. Contingency Kamin’s study: Group N-NL received 24 shocks during acquisition; p(shock / Light) = 8 / 24 = .33 and p(shock / No Light) = 16 / 24 = .67 Group NL received 8 shocks during acquisition; p(shock / Light) = 8 / 8 = 1.0 and p(shock / No Light) = 0 / 8 = 0 L for Group NL is a great predictor, but L for Group N-NL is a poor predictor; Therefore, little learning occurred to the Light = Blocking in the N-NL group

    10. Kamin’s (1968) Blocking Study

    11. Unblocking & Contingency Kamin’s 1969 study showed that he could block blocking by changing the UCS during the 2nd Phase: Phase 1: N-NL group gets a double shock as the UCS (16 trials N --> Shock Shock) Phase 2: All groups get a single shock as the UCS (8 trials NL --> Shock) Test Phase: Present L alone and now both the NL and the N-NL groups show strong suppression

    12. Latent Inhibition Phase 1: Present CS alone for several trials Phase 2: CS ? UCS for a limited # of trials Test Phase: CS ? ____ to see if conditioning occurred to the CS

    13. Latent Inhibition From Hall & Minor, 1984 CER Procedure: Phase 1: Train thirsty rats to drink from tube Phase 2: Separately present Tone during 3 Sessions; Controls had no Tone while in box Phase 3: All rats had Tone? Shock pairings Test Phase: Present Tone while rats were drinking from water tube

    14. Additional Phenomena In Classical Conditioning

    15. Temporal Conditioning Temporal conditioning is a form of classical conditioning in which the CS is the passage of time 5 minutes ---> UCS One example is called Sidman Avoidance; Rescorla (1966) used the procedure to test the effects of contingency

    16. Temporal Conditioning & Contingency Rescorla (1966) had dogs on a Sidman Avoidance task (not pure CC) in a 2-compartment chamber At the end of 10 seconds (the CS) shock would occur unless the dog jumped over the barrier, which canceled the shock for 30 seconds Separately, 3 groups of dogs were given a 5 sec tone as a CS: Group Pos had a positive contingency (CS-->Shock) Group Neg had a negative contingency (CS-->__; __-->Shock) Group Rand had a random contingency (CS-->__; CS-->Shock)

    17. From Rescorla (1966)

    18. Pseudoconditioning Pseudoconditioning has occurred when the CRs that are occurring to the CS are due to effects of sensitization rather than conditioning How does the experimenter know that the increase in CRs is due to learning and not some other factor like sensitization?

    19. Control Groups CS only - controls for effects of sensitization (where repeated presentations of a CS cause increased responsivity) UCS only - controls for effects of sensitization caused by the UCS: Pseudoconditioning Unpaired control - controls for the interaction effect of receiving CSs and UCSs which may produce sensitization. Problem is the negative contingency in this one produces inhibition Random control - controls for sensitization and does not produce inhibitory learning

    20. Control Groups Unpaired Control Group: The best for controlling for the effects of contiguity Random Control Group: The best for controlling for the effects of contingency

    21. Occasion Setting Acquisition: CS1(Blue Key) ? CS2(X on White) ? UCS (Food) CS2(X on White) ? ___ (No food) The Light becomes an occasion setter which is a stimulus that signals that another CS is likely to be followed by a UCS Test Phase: Present CS1(Blue Key) alone Present CS2(X on White) alone Present CS1(Blue Key) ? CS2(X on White) together

    22. Occasion Setting From Rescorla, 1985 Autoshaping procedure with pigeons: CS = X on White Key OS = Blue Key UCS = Food 12 Trials w/CS alone & 12 w/OS & CS per session Test Trials interspersed

    23. UCS Revaluation Following acquisition the UCS is presented at a stronger or weaker intensity, which then alters the strength of the response to the previously trained CS Phase 1: Pair a Lit Key (CS) with tasty water (UCS) in pigeons (autoshaping) Phase 2: In a separate location, pair the tasty water with illness Test Phase: Put pigeon back in operant chamber with Lit Key. Pigeon will stop pecking the Key and stop drinking the water

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