skinner’s “theory” of instrumental conditioning two-term contingency: r s r nature of...
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SKINNER’S “THEORY” OF INSTRUMENTAL CONDITIONING
• Two-term contingency: R SR
• Nature of reinforcer can vary: R S [SR, Sr, S-R, S-r].
• 3-term contingency (Discriminative operant)
SD : R SR (light: bar press food)
S : R SR (no light: bar press food)
• Chaining of discriminative operants:
• Nature of discriminative stimulus can vary: [exteroceptive, interoceptive, proprioceptive].
SKINNER’S “THEORY” (con’t.)
• Contingency of reinforcement can vary: Rn/t SR
• Schedule of reinforcement can vary: R SR
– subject must emit n responses within a particular time frame t.
• Verbal Behavior. Behavior that is reinforced by a member of one’s verbal community.
• Private events. Discriminative responding to proprioceptive or interoceptive stimuli (stimuli under our skin, Sd : r Sr)
Behaviorist Approach• All learned behavior (human and
animal) can be explained by the principles of classical and instrumental learning theory (2-factor learning theory).
• Classical conditioning:– assumes that CS’s and US’s can be paired arbitrarily.– assumes that temporal contiguity of CS and US is
necessary and sufficient for establishing CR.
• Instrumental conditioning:– assumes that responses selected for reinforcement
are arbitrary.
• No need to postulate mental processes.
EVIDENCE THAT QUESTIONED
BEHAVIORISTS’ ASSUMPTIONS• “Misbehavior” of organisms
• Garcia’s experiment on taste aversion
• Autoshaping and omission training
• Blocking
• Rescorla’s experiment on predictiveness of US.
• Experiments on animal cognition
– Hunter’s definition of representation– Radial maze– Matching-to-sample
GARCIA EXPERIMENT ON TASTE AVERSION
• Rats signalled about two types of noxious stimuli (nausea and shock) by two types of CS (taste and sound).– taste: liquid sweetened with saccharine– nausea: induced by lithium chloride
• Group I: Compound CS [taste & sound] Shock
• Group II: Compound CS [taste & sound] Nausea
• Effect of CS evaluated in 2-bottle choice test:– Bottle 1: saccharine flavored water– Bottle 2: water
• Group I: preferred sweet drink (natural preference)
• Group II: preferred water (avoid natural preference)
Blocking experiment (Kamin)
• Training: CS1 Shock:
CS1 + CS2 Shock
• Test: CS1 fear
CS2 no fear
Predictable and Unpredictable Occurrences
of FoodKey
Light
Food
KeyLight
Food
_______p(Food/Key Light) > p(Food/Key Light)
Predictable:
CS:
US:
_______p(Food/Key Light) =p(Food/Key Light)
Unpredictable:
CS:
US:
Omission Training
SD (Key light):
R (Peck):
SR (Food):
EVIDENCE THAT QUESTIONED
BEHAVIORISTS’ ASSUMPTIONS• “Misbehavior” of organisms
• Garcia’s experiment on taste aversion
• Autoshaping and omission training
• Blocking
• Rescorla’s experiment on predictiveness of US.
• Experiments on animal cognition
– Hunter’s definition of representation– Radial maze– Matching-to-sample
HUNTER ON “REPRESENTATIONS”
...If comparative psychology is to postulate a representative fact, ...it is necessary that the stimulus represented be absent at the moment of the response. If it is not absent, the reaction may be stated in sensory-motor term (Hunter, 1913, p. 21).
MATCHING-TO-SAMPLE
Peck Peck (food) Peck (no food)
Peck Peck (no food) Peck (food)
R R G
R R G
A. Matching-to-Sample
B. Oddity
A. Matching-to-Sample
Peck
RADIAL MAZE