PSY402 Theories of Learning

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PSY402Theories of Learning

• Wednesday
• January 15, 2003

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Examples of Conditioning

• Popcorn at the movies.
• Fear of flying -- stronger with more turbulence
  (a stronger UCS).
• An antelope shying away from low tree branches.
• Nausea at the smell of alcohol after a hangover.

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Conditioning Situations

• Sign-tracking (autoshaping) animals must
  recognize signs of food (UCS) and respond (UCR).
• Pigeons pecking at key.
• UCR, not an operant response, because behavior is
  specific to the stimulus.
• Eyeblink conditioning
• UCR is rapid, CR is slow.
• Many trials are needed (100 pairings)

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Fear Conditioning

• Avoidance is not a good measure of fear.
• Suppression of an operant behavior occurs with a
  feared stimulus.
• First an operant behavior is learned.
• Second a CS is paired with an aversive UCS.
• Third the CS is presented in the operant
  chamber.

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Suppression Ratio

• During CS
• SuppressionRatio During CS Without CS
• The amount of time during and without the CS is
  equal.
• The more fear, the lower the suppression ratio.
• Ratios typically fall between 0 and .5

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Flavor Aversion Learning

• Garcia rats will not drink water with saccharin
  if they get ill after drinking.
• Significant avoidance occurs after just one
  trial.
• Human food aversions are related to illness
  (89).
• Even if illness occurs hours later it is linked
  to the previous meal.
• Not cognitive know food not to blame

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Conditioning Paradigms

• Delayed conditioning the CS onset precedes the
  UCS onset.
• Trace conditioning the CS starts and ends
  before the UCS onset.
• Simultaneous conditioning the CS and UCS occur
  together.
• Backward conditioning the UCS starts and ends
  before the CS onset.

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Temporal Conditioning

• No CS is presented.
• The UCS occurs at regular intervals.
• A CR eventually occurs just before the UCS.
• Mechanism a biological state typically provides
  the CS.
• Waking up just before the alarm goes off.

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Importance of Timing

• A cue (CS) needs to be a good predictor of the
  UCS.
• Optimal inter-stimulus-interval (ISI) varies with
  the kind of response.
• The latency to respond is different for different
  reflexes (saliva, heart rate)
• Too long or too short intervals result in weaker
  conditioning.
• Intermediate CSs form a bridge.

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Importance of CS Strength

• CS intensity affects CR strength only when the CS
  intensity varies.
• If the CS strength is always the same, then the
  CS strength doesnt affect the size of the CR.
• Both dogs must bite in order for their size to
  matter.
• In order for CS intensity to matter, it must
  signal something.

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Importance of UCS Strength

• Strength of the CR increases with strength of the
  UCS.
• The more intense the air puff, the stronger the
  eyeblink CR.

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Salience of the CS

• Salience refers to how noticeable a stimulus is
  how likely an organism is to notice it in the
  environment.
• Preparedness (evolutionary predisposition) makes
  some CS more salient than others.
• The more salient the CS, the stronger the CR and
  faster learning.

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Predictiveness of the CS

• Predictiveness refers to how reliably the CS is
  associated with the UCS.
• When two or more CSs are present, only the most
  reliable elicits a CR.
• When the CS occurs with the UCS more often than
  the UCS occurs alone, conditioning occurs.
• A CS alone weakens conditioning.

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Blocking

• Presence of a previously conditioned CS (existing
  predictive cue) prevents conditioning of a new
  CS.
• Parent threats presence of fear of the parent
  prevents acquisition of fear to another stimulus.

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Implications for Parenting

• Threats (CS) should reliably be accompanied by
  punishment (UCS) or they will be ignored.
• Timing of threat (CS) and punishment (UCS) should
  be close together not wait until Dad gets home.
• Fear of parents (CER) may block conditioning of
  any other CS.