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Classical Conditioning

Classical Conditioning. Learning: What does it mean to learn?. Learning is the single largest area of Psychology second only to clinical psychology. I. Classical Conditioning – learning through association. Philosophical roots: English Empiricists

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Classical Conditioning

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  1. Classical Conditioning

  2. Learning: What does it mean to learn? • Learning is the single largest area of Psychology second only to clinical psychology

  3. I. Classical Conditioning – learning through association • Philosophical roots: English Empiricists • John Locke – Primary and Secondary Qualities • David Hume – Reflection , Cause and Effect

  4. Ideas • Anything that stimulates the CNS

  5. 1. Pavlov and the conditioned reflex • The procedure is what distinguishes classical conditioning from other modes of learning

  6. Classical Conditioning in America was Stated by Watson and Rayner (1920) • Albert was set on a rug, held by Rayner and presented with a fuzzy rabbit. • Watson slammed two sticks together behind Albert as he reached for the animal. • After several trials Albert began to cry when the rabbit was presented

  7. Watson, Rayner and Little Albert

  8. The Three Phase Process of Classical Conditioning

  9. Habituation • Works at the neuron level to organismic level. • Habituation decreases the responses over time both for magnitude and frequency per unit time. • The most basic level of learning. Requires no reinforcement.

  10. Habituation (cont.) • Habituation allows the organism to ignore irrelevant stimuli. • Dishabituation is the stopping of habituation to an attended stimuli

  11. Condition Stimulus (CS) • A neutral stimulus, can be sound, light or internal craving.

  12. Uncondition Stimulus (UCS) • The natural stimulus that drives the CNS to elicit the reflex. • In the vernacular of instrumental learning this hookup of the UCS-UCR is known as the reinforcement.

  13. Uncondition response (UCR) • The basic reflex that is become controlled by procedure.

  14. Reinforcement vs Reward • One reinforces a response! • One rewards the animal!

  15. Condition Response (CR) • The response when driven by the Condition Stimulus

  16. 2. Major phenomena of classical • Two types of “effective” procedures that lead the animal to predict up coming events.

  17. Delay Conditioning: requires only recognition

  18. Critical Measures: ½ mm movement is a response, Latency to onset of movement, Latency to peak of response.

  19. 3 Characteristics of Delay Conditioning • The CS starts before the UCS

  20. There is a time period between when the CS in On and the start of the UCS – known as the Inter-Stimulus-Interval (ISI).

  21. Both the CS and the UCS co-terminate.

  22. The association • The explicit pairing of the CS with the UCS • (in eye-blink, if tone and then air-puff) sets up the contingency that leads the animal to predict what is to come. • This analysis of expectation was put forth by Rescorla.

  23. Trace Conditioning: requires memory

  24. 3 Characteristics of Trace Conditioning • The CS starts before the UCS

  25. The CS turns “OFF” before the UCS comes “ON”.

  26. The time period between the CS turns “Off” and the UCS comes “On” is the trace interval (the inter – stimulus – interval).

  27. The animal must remember to delay its response, and respond only at the end of the trace interval.

  28. Backward Conditioning

  29. Backward Conditioning (cont) • UCS comes “ON” before the CS. • UCS goes “OFF” with “ON- set” of CS • Ineffective for producing a conditioned response.

  30. Simultaneous Conditioning: very hard to show.

  31. Formal Classical Conditioning is a Three Stage Process • Habituation – Paired Training - Extinction

  32. Pavlov’s study • Condition stimulus, CS, was the sound of a metronome (will become the condition reinforcer)

  33. The Uncondition Stimulus (UCS) was meat powder (the reinforcer).

  34. The uncondition response was drops of salivation.

  35. Condition response was salivation.

  36. Trial - By - Trial Presentation • Trials are presented singularly and continues until some criterion is met or a fixed number of trials completed.

  37. Paired trials • When both the CS and the UCS are presented in a fixed order and time frame • (an explicitly paired trial).

  38. CS Alone Trials • Periodically only the CS is presented • Known as CS alone trials. • Measure the effectiveness of the CS to drive the behavior

  39. Statistics • Mean and SD change in the timing or magnitude of the paired trials. • Mean and SD of the CS alone trials

  40. Results • In the beginning trials the CS does not elicit the CR

  41. Across trials there is a change in the ability of the CS to drive the CR. The change increase as the trials progress. • The CR looks like the UCR, but micro analysis of the two behaviors will show clear difference

  42. Results of Explicit Pairing CS-UCS • By the end of the trials, both for paired and CS alone trials, the CS is able to elicit the CR. • Magnitude increases, time shortens or frequency changes for the behavior

  43. How does one know that one has stimulus control? • Use Extinction trials.

  44. Present the trials in the manner of Habituation (but is not habituation) • Repeated presentation of the CS alone will drive the changes that were learned during CS presentation to zero.

  45. EXTINCTION • Note at the beginning of day 2, the first response is larger than last response on day one. Called spontaneous recovery.

  46. Generalization vs discrimination • Generalization is the tendency to respond to like stimuli the same way. • If a rabbit is trained on a 1200Hz tones, to a critiereon, his percent correct for a 800, or a 1600Hz tone will be less than the 1000Hz tones • See next slide

  47. Generalization gradient

  48. Discrimination training • The correct stimulus is explicitly paired with a given reinforcement (see Mauk and Ruiz slides 65- 71 below). • Or two different responses are paired with two explicitly different stimuli.

  49. The vast array of stimuli and condition responses

  50. Eyeblink Studies • First done by Ernest Hilgard in humans, dogs and monkeys 1928 – 1936).

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