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Classical Conditioning I. Classical Conditioning. Classical or Pavlovian conditioning. Unconditioned Stimulus (US). Automatically elicits a response (reflex) Unconditioned Response (UR). Food, Water, Sex, Pain, etc. Conditioned Stimulus (CS).
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Classical or Pavlovian conditioning Unconditioned Stimulus (US) Automatically elicits a response (reflex) Unconditioned Response (UR) Food, Water, Sex, Pain, etc. Conditioned Stimulus (CS) Initially “neutral” – Does not initially trigger same response as does the US lights, sounds, tastes, odors, etc. After pairings with the US, elicits a conditioned response
Some response systems that participate in classical conditioning • Endorphins and analgesia • Sexual arousal • Immune suppression/enhancement • Fear
heroin Siegel Ave. C Buddy Jimmy Favorite belt Etc. Euphoria Big departure from homeostasis
heroin Siegel Ave. C Buddy Jimmy Favorite belt Etc. Euphoria Smaller departure from homeostasis Compensatory Response
heroin Siegel Ave. C Buddy Jimmy Favorite belt Etc. Euphoria Even smaller departure from homeostasis Compensatory Response
heroin Siegel Ave. C Buddy Jimmy Favorite belt Etc. Euphoria Departure from homeostasis Compensatory Response
heroin Siegel New Context Euphoria Departure from homeostasis Compensatory Response
CS US Siegel Conc. Of drug in Brain Time since admin.
Montaigne: “My appetite comes to me while eating” -Of Vanity (1500-ish)
Autoshaping When there is a contingency between a tangible CS and a pleasurable US, the CR is directed at the CS. Sign tracking (cf. Goal tracking) Pigeons key light CS food US response: peck key light CS Rats insert lever CS food US response: lick lever ball bearing CS food US response: handle ball bearing
Autoshaping Movies Long-box autshaping Omission training
Fear Conditioning (tone) Notation: Tone + Or ToneShock (shock)
(CR’s) Blood pressure Heart Rate Stress Hormones Freezing After one or two pairings… (CS)
a a + b Suppression Ratio a = responses during the CS b = responses prior to the CS On first Tone-Shock trial: a = 30; b = 30. 30/(30+30) = 0.50 After 10 Tone-Shock trials: a = 3; b = 20. 3/(3+20) = 0.13
Tone Shock Fear-Potentiated Startle (Davis) Train: Test: Startle Stimulus (Loud Noise) Alone Vs. Startle Stimulus + Tone DV: How high do they jump?
Feed-forward vs. Feedback
Generalization Trained frequency CR’s Tone frequency
What determines the form of the CR? Stimulus Substitution Behavior Systems Opponent Processes
Stimulus Substitution (the CS takes the place of the US) • Pavlov: UR = Salivation, CR = Salivation • Cocaine: UR = Activity, CR = Activity • Cyclophosamide: UR & CR = immune suppression. • Autoshaping: CR for water = Closed beak, CR for grain = Open beak
Form of the CR in Sign Tracking UCS = Water (note the closed beak) UCS = Food (note the open beak) video From Jenkins & Moore, 1973
However… • Fear conditioning: CR = freezing, UR = activity • CS can determine form of CR
However… • Fear conditioning: CR = freezing, UR = activity • CS can determine form of CR • Interval between CS and US matters • Long delay: General search CR • Short delay: Focal search CR
Behavior Systems Theory • Holland (1984); Timberlake & Silva; Akins The CS and US engage the same “behavior system” – e.g., appetitive, sexual, defensive. The form of the CR depends on the length of the delay between CS and US. Overt CR is flexible – depends on situation