Operant Conditioning

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Operant Conditioning

• Thomas G. Bowers, Ph.D.
• Penn State Harrisburg

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Operant Conditioning

• Thought to operate upon the environment
• So-called voluntary behavior
• Thorndike aimed to explain goal directed behavior
• Developed Law of Effect

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Law of Effect

• Behavior is sensitive to its consequences
• Positive reinforcement - Pleasurable consequences
  stamp in the behavior
• Punishment - Unpleasant events stamp out the
  behavior

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Behavior-consequence Relationship

• Positive reinforcement acts to increase the
  probability of behavior
• Punishment acts to decrease the probability of
  behavior

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Behavior-consequence Relationship

• Negative reinforcement (or escape) acts to
  increase behavior which eliminates or removes the
  negative stimulus
• Omission removal of a positive stimulus decreases
  behavior

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Response-consequence Relationships
Stimulus
Response
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Conditioning and Extinction

• Responses are developed by a shaping process of
  successive approximations
• Extinction refers to the cessation of
  reinforcement

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Behavioral Units

• Acquisition

Extinction
Response/Min
Time
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Contingency Learning
1.0
P(Sr/R)
.0
P(Sr/No Res)
1.0
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Operant Contingency Space

• Reinforcement has a contingent effect, increasing
  behavior, while punishment or even
  non-reinforcement will decrease behavior
• When reinforcement and responses are independent,
  or noncontingent, then learned helplessness
  results

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Operant Contingency Space

• Learned helplessness resembles depression
• Seligman developed the paradigm
• Leads to a global failure to initiate behavior
• Associated with depletion of monoamine
  neurotransmitters

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Operant Conditioning

• What is learned?
• R - S relationship?
• How can something temporally remote (i.e.
  following) cause an event?
• Some theorists emphasize S - R relationships

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Avoidance Behavior

• Much of our day to day behavior may serve to
  avoid negative or aversive stimuli or
  consequences
• Signaled avoidance trials
• Early training does not avoidance, but escapes
  the stimulus
• Latency tends to decrease

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Avoidance Behavior

• Shock postponement procedure
• Also called free-operant avoidance
• Sidman avoidance
• Most animals manage to learn this well, with few
  actual shocks experienced

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Theories of Avoidance

• Does the animal know?

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Theories of Avoidance

• Two factor theory - Mowrer
• Initial learning by reinforcement of escape
  behavior
• Classical conditioning also occurring, and CS
  acquires fear eliciting properties
• Response here is reinforced by fear (CS) removal
• Avoidance behavior results

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Theories of Avoidance

• Tests to inhibitory procedures appear to confirm
  predictions
• Some problems, though
• animals will respond reliably even if only a
  reduction of shock frequency is the contingency
• there is little evidence of conditioned fear in
  well-trained animals

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Theories of Avoidance

• Some problems, though
• avoidance of extinction
• avoidance can be extinguished, but by response
  blocking

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Cognitive Theories

• Expectancy theory
• Organism prefers no shock to shock
• Organism expects if it responds, no shock will
  occur
• Organism expects if it does not respond, shock
  will occur
• Expectancies are strengthened when confirmed,
  weakened when disconfirmed

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Cognitive Theories

• Expectancy theory
• Probability of avoidance increases as the degree
  of confirmation increases

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Biological Theories

• Bolles emphasized the adaptive significance to
  persistent avoidance learning
• Described a repertoire of defensive reactions
• Species-specific defensive reactions (SSDR)

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Biological Theories

• Hierarchical organization
• Some patterns of responses are much easier to
  acquire than others

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Conditioned Reinforcement

• Neutral stimuli can also become a conditioned
  reinforcer
• Predictiveness, informativeness is important to
  becoming a secondary reinforcer
• Animals will respond for the opportunity to gain
  informative stimulus conditions

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Applications of Secondary Reinforcement

• Token economies
• Common in our environment
• Generalized secondary reinforcers
• Functions
• Provide feedback
• Provide information about what to do next
• Serve to bridge long gaps in reinforcement
• Economies now build in inflation