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Learning

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					Learning

Chapter 5
                    Learning
• A relatively permanent change in behavior
  brought about by experience.
  – Classical Conditioning
  – Operant Conditioning
            Pavlov’s Discovery
• Pavlov was not a psychologist but was a
  physiologist who studied the digestive system of
  dogs.
• He began to notice that the dogs he was studying
  would salivate when they saw the research
  assistant, who normally fed them, even when he
  had no food and was not feeding them.
• Pavlov became curious and devised an
  experiment.
            Classical Conditioning
 A type of learning in which a neutral stimulus comes to
  bring about a response after it is paired with a stimulus that
  naturally brings about that response.
   Neutral Stimulus: A stimulus, that before conditioning, does not
    naturally bring about the response of interest.
   Unconditioned Stimulus: A stimulus that naturally brings about a
    particular response without having been learned.
   Unconditioned Response: A response that is natural and needs
    no training.
   Conditioned Stimulus: A once-neutral stimulus that has been
    paired with an unconditioned stimulus to bring about a response
    formerly caused only by the unconditioned stimulus.
   Conditioned Response: A response that after conditioning,
    follows a previously neutral stimulus.
The Classical Conditioning Process
        and Pavlov’s Dogs
• Pavlov began by performing an operation on the
  dogs which would divert the saliva from their
  mouth to a container for measuring.
• Phase 1: Pavlov placed meat powder in the dogs
  mouth and confirmed the dogs automatic
  salivation. Pavlov then confirmed no salivation
  when the dog only heard a musical tone.
  – The two basic components of Pavlov’s experiment.
     • Reflex: a quick automatic response
     • Neutral Stimulus: does not trigger a reflex
• Phase 2: The musical tone (Neutral Stimulus) was
  sounded and then the meat powder
  (Unconditioned Stimulus) was placed in the dogs
  mouth. Result= salivation (Unconditioned
  Response) This process was repeated several
  times.
• Phase 3: The tone was sounded but no meat
  powder was given. Result= salivation
  – Tone (Conditioned Stimulus)>>>>Salivation
    (Conditioned Response)


  The conditioning process has now occurred. The tone
    has now changed from a neutral stimulus to give a
    conditioned response of salivation.
•   What would happen if you continued to sound the tone repeatedly without pairing it
    with the meat powder? Extinction: The gradual disappearance of a conditioned
    response. A basic phenomenon of learning that occurs when a previously conditioned
    response decreases in frequency and eventually disappears.
•   But the conditioning is not totally forgotten. After pairing the meat powder and the
    tone again for only one or two times the dog will began to salivate again. This is called
    reconditioning: the relearning of a conditioned response following extinction.
•   But sometimes the pairing may not be needed to get the conditioned response. The
    dog may hear a musical tone or similar sound months after extinction has occurred and
    salivate. This is called spontaneous recovery: the reemergence of an extinguished
    conditioned response after a period of rest and with no further conditioning.
•   Stimulus Generalization: occurs when a conditioned response follows a stimulus that is
    similar to the original conditioned stimulus. This is why if we get sick from drinking
    soured milk we will know to avoid any other dairy product that smells the same way as
    the soured milk.
•   Stimulus Discrimination: The process that occurs if two stimuli are sufficiently distinct
    from each other that one evokes a conditioned response but the other does not. This is
    why you may wake up when you hear your own child cry out for you in the middle of
    the night but not wake up when you have family visiting and your niece or another child
    begins to cry.
         Operant Conditioning
 Skinner noted that, during instrumental
  conditioning, an organism learns a response by
  operating on the environment.
 Operant Conditioning: Learning in which a
  voluntary response is strengthened or weakened,
  depending on its favorable or unfavorable
  consequences.
 To study operant conditioning Skinner developed
  the Skinner Box in which an animal would be
  either rewarded or punished for an action and
  then the results would be recorded.
• Unlike the classical conditioning process in which
  the salivation of the dog had no effect on
  whether the tone would be sounded or not
  operant conditioning is different.
• Reinforcer: any stimulus that increases the
  probability that a preceding behavior will occur
  again.
   – Positive Reinforcer: A stimulus added to the
     environment that brings about an increase in a
     preceding response. Ex. Your child cleans their room
     and you give them $.
   – Negative Reinforcer: An unpleasant stimulus whose
     removal leads to an increase in the probability that a
     preceding response will be repeated in the future. Ex.
     If you have a headache this is an unpleasant stimuli so
     you take Tylenol, a neg. reinforcer, to take away the
     pain.
• Punishment: A stimulus that decreases the
  probability that a previous behavior will occur
  again.
  – Ex 1. A child is spanked after hitting his brother.
  – Ex 2. A child is put in time out after lying.
  – Ex 3. A child is not allowed to spend the night with
    a friend after refusing to clean their room.
  – Ex 4. A child has their DS game taken away after
    talking back to their father.
• Schedules of Reinforcement:
  – Reinforcement is based on a number of responses
     • Fixed Ratio Schedule: A schedule of reinforcement that
       is given only after a specific number of responses are
       made. Ex. A rat presses a bar and is only rewarded with
       a pellet after 10 bar presses.
     • Variable Ratio Schedule: A schedule by which
       reinforcement occurs after a varying number of
       responses rather than after a fixed number. Ex. A rat
       presses a bar and is rewarded with a pellet after the
       10th bar press one time and then after the 25th bar
       press and then the 100th bar press. The reward for the
       bar press is still there but it varies and will average out
       to be a VR of 30. Gambling is another example of
       unpredictable lever pulls and rewards for them.
• Continued
  – Reinforcement is based on a length of time.
     • Fixed Interval Schedule: A schedule that provides
       reinforcement for a response only if a fixed time period
       had elapsed. Ex. A rat is rewarded for his first response
       after 10 minutes has past from his last response no
       matter how many times he presses the bar.
     • Variable Interval Schedule: A schedule by which the
       time between reinforcements varies around some
       average rather than being fixed. Ex. The rat is rewarded
       with a pellet after 10 seconds, 60 seconds or 2 minutes
       no matter how many times he presses the bar. The
       reward times vary but may have an average of 30
       seconds.
 Forming and Strengthening Operant Behavior.
 Shaping: The process of teaching a complex
  behavior by rewarding closer and closer
  approximations of the desired behavior. Ex.
    Give dog a treat when he sits down
    Give dog treat when he sits and then partially lifts his
     paw
    Then only reinforce with a treat when the dog sits and
     completely lifts his paw.
    Finally the dog will only get a treat when he sits and
     lifts his paw and then shakes your hand.
 Behavior Modification: A formalized technique for
  promoting the frequency of desirable behaviors and
  decreasing the incidence of unwanted ones.
  Cognitive Processes in Learning
• Learned Helplessness: A process in which a
  person or animal stops trying to exert control
  after experience suggests that no control is
  possible.
• A tendency to give up on efforts to control our
  environment.
• Ex. Battered women.
 Cognitive Approaches to Learning
• Latent Learning: Learning in which a new
  behavior is acquired but is not demonstrated
  until some incentive is provided for displaying it.
   – Ex. Never having gone to Kings Pharmacy on a
     Saturday but yet you are able to tell your mother it is
     closed on Saturdays when she mentions she needs to
     go get her medicine.
• Cognitive Map: A mental representation of
  spatial locations and directions. (some physical
  arrangement).
   – Ex. When a visitor to your school asks you how to get
     to the library you can tell them where to go.
• Observational Learning (Social Learning):
  Learning by observing the behavior of another
  person or model.
  – Ex 1. We learn not to touch the hot stove when we
    see someone else get burned.
     • Vicarious Conditioning: A kind of observational learning
       through which a person is influenced by watching or hearing
       about the consequences of other’s behavior.
        – Ex. Bandura found that children who saw an adult rewarded for
          aggressive acts showed the most aggressive acts themselves
          when involved in play activities.

				
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posted:7/30/2012
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