learning by xiangpeng

VIEWS: 11 PAGES: 44

									Behavioral Development and
         Learning
              Notes p. 3




  AU Luescher DVM PhD Dipl ACVB
   Director, Animal Behavior Clinic
             Learning in Animals
• Learning through
  exposure (early
  experience learning)
• Conditioning
   – Modifying responses
     to stimuli
   – Forming associations
     between stimuli
   – Forming associations
     between stimuli and
     responses
     Early Experience Learning
• Complexity of early
  environment
• Management of young
  animal
• Effect of early stress
• Critical Periods
• Sensitive Periods
   – Imprinting
   – Socialization
      Early Experience Learning:
      Environmental Complexity
• Effect on sensory
  abilities:
  – Kittens reared in darkness
    and put into cylinder with
    only horizontal or vertical
    stripes: respond only to
    vertical or horizontal
    objects: deficit in visual
    cortex.
        Early Experience Learning:
        Environmental Complexity
• Effect on
  learning ability:
   – Rats selected for
     maze
     brightness/dullne
     ss are equally
     bright or dull if
     reared in an
     enriched or
     restricted
     environment,
     respectively
                       Early Stress
• Early stress “primes” the
  HHA axis
• May have beneficial
  effects
• Stress needs to be applied
  during development of
  HHA axis
   – Chicks 3rd week of
     incubation
   – Piglet from day 104 of
     gestation
   – Altricial animals first days
     after birth
                    Early Stress
Animals that experienced
  early stress
• React more strongly
  endocrinologically to
  acute stressors
• React less strongly
  endocrinologically to
  chronic stressors
   – less deleterious effects
     such as immune
     suppression
                   Early Stress
Neonatal stress may have
  beneficial effects on the
  development of altricial
  animals:
• Kittens open eyes
  sooner, leave nest
  sooner
• Siamese kittens develop
  color points sooner
• Decreased emotionality
• Increased resistance to
  some diseases
              Sensitive Periods
• Period during
  development in
  which certain
  experiences need to
  be made for normal
  development. Lack
  of that experience
  during critical
  period has lifelong
  effects that are
  difficult to reverse.
• Periods phase in and
  out
Socialization
• Need for exposure in
  sensitive period
• Exposure needs to be
  continued after
  sensitive period
• Reduces fear and
  aggression
• Reduces predatory
  behavior
  Problems with
   Socialization
• Separation form own
  species results in fear
  of that species
• Lack of human contact
  results in fear of
  humans
• Lack of socialization
  to children leads to
  fear of or aggression
  to children
  Early Environmental Exposure
• Habituation to stimuli
  begins with
  development of senses
• Habituation is easiest
  before fear develops
• Lack of exposure to
  stimuli results in fear
  of these stimuli
  (“kennellosis” in dogs)
           Types of Conditioning
• Habituation
  – Modifying responses
    to stimuli
• Classical
  conditioning
  – Forming associations
    between stimuli
• Operant conditioning
  – Forming associations
    between stimuli and
    responses
 Cognitive Abilities of Domestic
            Animals
• Do animals reason?
   – They can form simple abstract
     concepts)
• Do animals act out of spite?
• Can animals be jealous?
   – These concepts involve
     rationalization of behavior and
     moral judgment
• Can animals be bored?
   – Boredom is a poor explanatory
     concept in most cases
                Habituation
• The animal stops
  reacting to a neutral
  stimulus
• The animal learns that
  a stimulus has no
  consequence (the
  stimulus doesn’t mean
  or predict anything)
• Active learning
  process vs forgetting
            Habituation-
        Spontaneous Recovery
• If a stimulus to which
  the animal was
  habituated is not
  presented until a long
  time has passed, the
  animal will react to it
  again.
       Classical Conditioning
            (IP Pavlov)
• Forming associations between stimuli
        Classical Conditioning
             (IP Pavlov)
• A previously neutral stimulus attains a
  meaning/becomes a predictor (i.e., a
  conditioned stimulus) for something after it
  was paired with an unconditioned (inherently
  meaningful) stimulus
• A conditioned response is shown to the
  conditioned stimulus that resembles the
  response to the unconditioned stimulus
   Classical Conditioning: Examples
• Can opener or food dish
            food
• Door Bell       Person at
  door
• “Walk”, “car”
        excitement
• Drive to obedience practice
         excitement or stress
• Command         prompt
• Clicker         food
           Classical Conditioning
• Classical conditioning
  always occurs, not just if
  it is the trainer’s intention
• Dogs will associate a
  situation with the
  experience they made
  (e.g., training, veterinary
  office)
• Classical conditioning can
  interfere with operant
  conditioning
          Extinction of Classically
           Conditioned Response
• If the CS is presented
  repeatedly without US,
  the animal learns that the
  CS has no meaning (it
  habituates to the CS)
• E.g. obedience
  commands that are not
  followed by any action
  (prompt)
• E.g. clicker not followed
  by food
         Operant Conditioning
            (BF Skinner)
• Association between
  stimulus and response
• Learning that a
  particular response has
  a particular
  consequence
           Law of Effect
            Pleasant    Strengthened
            consequence
Behavior


            Unpleasant  weakened
            consequence
            Skinner Box - Rat
• Lever
• Chute for pellet
• metal grid
  (shock)
• Light

• Response is
  lever pressing
         Skinner Box - Pigeon

• Key/light
• Food hopper
• Metal grid (shock)
              Definitions

           Reinforcement   Punishment


Positive   Give Food       Inflict pain


Negative   Terminate       Remove
           shock           attention
                  Motivation
• Dog must be keen on
  getting the reward
  (don’t feed right before
  training with food
  rewards, withhold
  attention outside of
  training)
• Reward must be
  valuable (use treats
  that are much better
  than the dog’s regular
  food)
         Cue Arousal Principle
• Dog must be at proper
  level of arousal
• If dog is either sleepy
  or excited, cues need
  to be stronger
• Don’t “hype” dog up
  before training or s/he
  won’t learn
       Conditioning a Behavior
• Prompting and fading
• Rewarding spontaneous behavior
• Shaping (successive approximation)
• Continuous reinforcement (fast learning)
• Discrimination training (command)
• Intermittent reinforcement (persistent
  behavior)
• (Avoidance conditioning)
Prompting and Fading
          • A prompt is any
            (humane) way of
            inducing a behavior
          • A food lure is a type
            of prompt
          • Fading refers to
            gradually removing
            the prompt
       Rewarding Spontaneous
             Behavior
• Wait until a behavior
  that resembles the
  target behavior occurs,
  and reward
• Clicker training is
  particularly suited for
  that type of training
  Shaping
• Training by
  successive
  approximation
• Taking advantage
  of variability of
  behavior
• Becoming
  gradually more
  demanding
• Rewarding only the
  best behavior
     Continuous Reinforcement


• Every response that
  meets the criterion
  is rewarded
• Results in fast
  learning
      Discrimination Training
• Once a reinforceable behavior can be
  reliably prompted or predicted, put it on cue
• Only reward behavior when on cue
• In skinner box:
  Light      response       reinforcement
  No light   response       no reinforcement
     Intermittent Reinforcement
• Not every response is reinforced
• Makes behavior more persistent
  (more resistant to extinction)
• Makes response more sluggish
• Can impose stress (makes
  situation less predictable, and
  diminishes the degree of control
  the dog has over the situation)
        Conditioning with
      Negative Reinforcement
• Escape conditioning
  – Learning that a
    behavior can terminate
    an aversive stimulus
    (e.g., shock)
• Avoidance
  conditioning
  – Learning to perform a
    behavior to avoid an
    aversive stimulus
      Conditioning with Negative
            Reinforcement
• Shock collar
• Ear pinch?
• Choke chain?

• Fear aggression
• Escape behavior
               Extinction of
             Operant Response
• The animal learns that
  the response is no
  longer successful
• Rate of extinction
  depends on:
   – Duration of training
     (overlearning)
   – reinforcement
     schedule
   – Type of reinforcer
     (negative
     reinforcement)
              Extinction of
            Operant Response
Frustration effect or
  extinction burst:
Behavior becomes more
  intense
• Behavior becomes
  more variable
• Useful when come to a
  training plateau (need
  variability to shape
  behavior)
Principles and Use of
    Punishment




  AU Luescher DVM PhD DACVB
  Director, Animal Behavior Clinic
           Law of Effect
            Pleasant    Strengthened
            consequence
Behavior


            Unpleasant  weakened
            consequence
             Punishment
           Some Basic Facts
• Complex technique that is difficult to use
  and therefore often ineffective in practice
• If effective, it works within 3-4 times
• Punishment inhibits learning
• Punishment can have serious side effects
• Punishment does not teach appropriate
  behavior
• Punishment is not suitable for teaching
Effective Punishment

           •   Motivation strength
           •   Contingency
           •   Intensity
           •   Timing
           •   Alternative
     Alternatives to Punishment
• Do not reward            •Response substitution
• Reduce motivation        •Systematic desensitization
• Provide an alternative   •Counterconditioning

								
To top