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Example: “Bell” and Food CS US URCR Later Trials CS US UR First Few Trials Time CS = bell US = food UR = salivation CR = salivation 3
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PRINCIPLES AND APPLICATIONS OF CLASSICAL CONDITIONING
Chapter 4
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Example: “Bell” and Food
CS
US
URCR
Later Trials
CS
US
UR
First Few Trials
TimeCS = bellUS = foodUR = salivation
CR = salivation
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Central Players
Conditioned Stimulus (CS)
Unconditioned Stimulus (US or UCS)Initially “potent” – Initially elicits a response (inside or outside)
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
Food USHunger (inside and hidden)Salivation (outside and observable)
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1.What are the CS and US?
A pigeon pecks a light that signals the presentation of food
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Form of the CR
From Jenkins & Moore, 1973
US = Water (note the closed beak)
US = Food (note the open beak)
video
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Autoshaping (Sign Tracking)
When a localized CS and an “appetitive” US are paired, a CR is sometimes directed at the CS .
PigeonsCR: peck key light CS
Rats
key light CS food US
insert lever CS food USCR: lick lever
• Long-box autoshaping• Omission training
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Goal TrackingWhen a localized CS and a “appetitive” US are paired, a CR is sometimes directed at the site of the US.
Rats tone CS food USCR: check food magazine
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Conditioning of Hunger9
UCS: taste and smell of food UCR: internal physiological changes that
prepare us to digest and metabolize food e.g., secretion of saliva, gastric juices, insulin
Important: insulin lowers blood sugar, which stimulates hunger, which motivates eating
CS: Kitchen, refrigerator, sight of food, Tim Horton sign
CR: Hunger as a conditioned response
Conclusions
1. Conditioned behaviour is “evoked” by the CS, it is not “chosen” by the organism
2. The situation, species, and procedures used can affect whether animals what the animal does.
3. Internal states can cause approach to the CS or the US in appetitive conditioning.
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The Conditioning of Fear11
Conditioning of internal states motivate avoidance of the CS or the US in aversive conditioning
Escape FreezeFlight/Flinch
USCS
Some Specific Conditioned Responses
Time
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Conditioned emotional response Stage 1: Animal must first learn to bar
press for reward Stage 2: A neutral stimulus (CS) is paired
with an aversive stimulus (UCS) Stage 3: The CS is presented during
operant responding Conditioned fear, and specific conditioned
responses, such as freezing, will cause the animal will reduce or stop responding
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The level of fear is assessed with a suppression ratio Suppression ratio =
CS responding/(CS responding + Pre-CS responding)
Interpretation of a suppression ratio Values can range from 0 to 0.5 0.5 means that fear conditioning has not
occurred 0 indicates total conditioning
Conclusions 4. Conditioning of internal states
motivates avoidance of the CS or the US in aversive conditioning
5. Form of CR changes with ISI (This is why conditioned suppression catches them all)
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2. What are the CS and US?16
Garcia Effect17
The classic Flavor Aversion Experiments were conducted by Garcia et al. (1957) Although rats generally like saccharin very
much, they found that rats would not consume saccharin if illness followed its consumption
The illness did not result from the saccharin, though, but rather from either high doses of irradiation or from doses of Lithium Chloride
Taste Aversion18
Flavor Aversion Learning19
Flavor aversion: avoidance of a flavor that precedes an illness experience
Flavor aversion develops rapidly Often after one pairing of flavor and illness May occur even if there is a long time
interval between the flavor and the illness
Aversion as CR Negative state Not conditioned illness May involve a conditioned disgust
reaction
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Conclusions
6. What constitutes a “pairing” depends on the response system (There is no “optimal ISI”)
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3. What are the CS and US?22
Eye Blink Conditioning23
Procedure: CS: tone UCS: puff of air/paraorbital shock CR: blink UCR: blink
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Noteworthy characteristics: UCR and CR differ slightly
UCS elicits a rapid eyeblink response CS produces a slow, gradual closure of the eye
Eyeblink conditioning is slow It may take up to 100 CS-UCS pairings to
produce responding on 50% of trials
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Diagnostic tool27
4. What are the CS and US?
An addict goes into severe withdrawal after seeing the dealer’s door
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Trial 1
Euphoria
Dealer, copping corner, corner syringes, needles, cotton balls, lighters, rubber tying-off cords and stainless-steel spoons
Pre-Drug CSs Drug US
heroin
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Trial 5
heroinEuphoria
Pre-Drug CSs
Dealer, copping corner, corner syringes, needles, cotton balls, lighters, rubber tying-off cords and stainless-steel spoons
Pre-Drug CSs Drug US
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Trial 10
heroin
Dealer, copping corner, corner syringes, needles, cotton balls, lighters, rubber tying-off cords and stainless-steel spoons
Pre-Drug CSs Drug US
No Euphoria (Withdrawal Eliminated)
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Opiate AddictionAdministration Decreased Blood Pressure Skin Flushed and Warm Meiosis Drying of Secretions Respiratory Depression Antitussive Relaxation Hyperthermia
Withdrawal Increased Blood Pressure Chilliness and Gooseflesh Mydriasis Lacrimination Yawning and Panting Sneezing Restlessness Hypothermia
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Mydriasis33
Some Controlled Experiments Mor-ROOM/Sal-CAGE
Morphine in a distinctive room Saline in the home cage
Mor-CAGE/Sal-ROOM morphine in the home cage saline in a distinctive room
Saline saline in both environments
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Test Day: No DRUG in ROOM
Conditioning Trials
• Acquisition curve• Non-linear• Asymptote
Conditioning Trials
CR
Stre
ngth
asymptote
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Conditioning Occurs Over Trials
(S) Saline in Room
(M-HP) Mor in Room
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Extinction
Trials/Time
Stre
ngth
of C
RAcquisition Extinction
CS&US CS alone
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Extinction of Tolerance
Acquisition Extinction Test 3 Mor in Room 9 Placebo in RoomGroup Extinction (M-P-M)
6 Mor in Room 9 Rest in home CageGroup No Extinction (M-rest-M)
Mor in Room
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Rested animals show a CR (tolerant)
Extinguished animals(tolerance is undone)
Applications: Absence of Pre-Drug CSs42
Heroin Overdose Death 43
Overdose and Death
heroinNew Context
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Conclusions
7. Conditioned responses can be “compensatory”, bringing the organism back to homeostasis
8. Contexts can be conditioned (Best treatment for addiction is the original context).
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