PSY 402

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PSY 402

• Theories of Learning
• Chapter 3 Nuts and Bolts of Conditioning
• (Mechanisms of Classical Conditioning)
  

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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 you can know the food is not to
  blame and still feel an aversion to it.

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Factors Affecting Conditioning

• Timing how closely in time are the CS and UCS,
  and which occurs first.
• Novelty of the CS and UCS.
• Intensity (strength) of the CS and UCS.
• Consistency of the pairing between the CS and
  UCS.
• If one or the other appears alone then
  conditioning is weakened.

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Stimulus Presentation 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.
• These paradigms will be on the midterm

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3.8 Different ways to present CS and US in time
This works best
The longer the gap (trace interval) the worse
this works
This isnt as good as delayed
This doesnt work at all
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Massed vs Spaced Trials

• Better learning occurs when trials are spaced out
  over time (spaced), rather than bunched together
  (massed).
• Memory consolidation or rehearsal may be needed
  between trials.
• The ratio between the exposure to the CS and the
  time in-between is the important factor.
• If both are the same duration, learning is weaker.

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3.9 Trial spacing in Pavlovian conditioning
This works best
This doesnt work as well
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Importance of Novelty

• Preexposure to the CS (before it is paired with
  the UCS) reduces learning.
• Called latent inhibition because it inhibits
  learning of the CS-UCS association.
• The same thing happens with preexposure to the US
  (before it is paired with the CS).
• Called the US preexposure effect
• Other, more novel stimuli are more likely to
  become associated with the UCS.

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Stimulus Intensity (Strength)

• The stronger the US (UCS), the faster the
  learning and the stronger the association.
• The stronger the CS, the better the learning.
• Salience how attention-getting the stimulus is
  in relation to other stimuli in the environment.
• The most salient CS becomes associated with the
  UCS.
• An overpowering CS may elicit a response of its
  own, preventing learning.

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Pseudo-conditioning

• Responses to the CS may occur due to the strength
  of the UCS, not learning.
• Once air has been puffed at the eye, blinking may
  occur in response to any stimulus that comes
  next, without any learning.
• Sensitization resulting from an intense UCS may
  cause the response to a CS to be increased, even
  when there is not greater learning.
• A control group lets you tell the difference.

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3.10 Bernsteins experiment on taste aversion
learning
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Acquired Changes in Response

• Habituation response to a repeated stimulus
  decreases with non-threat experience.
• Sensitization response to a variety of stimuli
  increases with a single threat experience.
• Examples
• Ingestional neophobia, fear of new food
• Rats orient less toward light, startle decreases
• Chicks are less frightened by shadows flying
  overhead with repeated exposure.

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Factors Affecting Conditioning

• Timing how closely in time are the CS and UCS,
  and which occurs first.
• Novelty of the CS and UCS.
• Intensity (strength) of the CS and UCS.
• Consistency of the pairing between the CS and
  UCS.
• If one or the other appears alone then
  conditioning is weakened.

14
Stimulus Presentation 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.
• These paradigms will be on the midterm

15
3.8 Different ways to present CS and US in time
This works best
The longer the gap (trace interval) the worse
this works
This isnt as good as delayed
This doesnt work at all
16
Massed vs Spaced Trials

• Better learning occurs when trials are spaced out
  over time (spaced), rather than bunched together
  (massed).
• Memory consolidation or rehearsal may be needed
  between trials.
• The ratio between the exposure to the CS and the
  time in-between is the important factor.
• If both are the same duration, learning is weaker.

17
3.9 Trial spacing in Pavlovian conditioning
This works best
This doesnt work as well
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Importance of Novelty

• Preexposure to the CS (before it is paired with
  the UCS) reduces learning.
• Called latent inhibition because it inhibits
  learning of the CS-UCS association.
• The same thing happens with preexposure to the US
  (before it is paired with the CS).
• Called the US preexposure effect
• Other, more novel stimuli are more likely to
  become associated with the UCS.

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Stimulus Intensity (Strength)

• The stronger the US (UCS), the faster the
  learning and the stronger the association.
• The stronger the CS, the better the learning.
• Salience how attention-getting the stimulus is
  in relation to other stimuli in the environment.
• The most salient CS becomes associated with the
  UCS.
• An overpowering CS may elicit a response of its
  own, preventing learning.

20
Pseudo-conditioning

• Responses to the CS may occur due to the strength
  of the UCS, not learning.
• Once air has been puffed at the eye, blinking may
  occur in response to any stimulus that comes
  next, without any learning.
• Sensitization resulting from an intense UCS may
  cause the response to a CS to be increased, even
  when there is not greater learning.
• A control group lets you tell the difference.

21
3.10 Bernsteins experiment on taste aversion
learning
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Conditioned Inhibition

• A CS can signal the presence of a UCS.
• This is called excitation, CS
• A CS that never appears with the UCS signals the
  absence of the UCS. It becomes an all clear
  signal.
• This is called inhibition, CS-
• In fear conditioning an excitor produces anxiety,
  an inhibitor produces relief or safety.

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Detection of Conditioned Inhibition

• Summation test
• Step 1 Condition two stimuli as CS CS-
• Step 2 Present both together.
• Step 3 Present the CS alone, with a neutral
  stimulus, or with another CS.
• The results of Step 2 should be less than Step 3.
• Retardation of Acquisition test turning a CS-
  into a CS takes longer than creating a CS from
  a neutral stimulus.

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3.11 Hypothetical effects of an excitor alone,
with an inhibitor, and with another excitor
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3.12 Hypothetical effects of pairing an
inhibitor with a US
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Producing Conditioned Inhibition

• Differential (discriminative) inhibition
• Present two stimuli, one always with the UCS, the
  other always without the UCS.
• Conditioned inhibition procedure
• Present the CS with the UCS sometimes, but pair
  the CS with another stimulus (X) when the UCS is
  not present. The CS-X combination will produce
  inhibition.
• CS-X is called a compound CS

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More Inhibition Procedures

• Explicitly unpaired (negative correlation)
• The CS and UCS never appear together.
• Backward conditioning is a type of negative
  correlation because the CS always appears after
  the UCS.
• Inhibition of delay when the CS is lengthy
  (e.g., a very long tone or light), the CR will
  occur closer in time to the UCS with practice.

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Necessary Conditions for Inhibition

• The CS must occur without a UCS in a situation
  where a UCS is possible when it is otherwise
  expected.
• The CS then becomes a signal of the absence of
  the UCS.
• The CS is irrelevant and no attention is paid to
  it if there is no relation (contingency) between
  it and the UCS.

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3.13 Rescorlas experiments CS-US contingency
in conditioning
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Blocking and Unblocking

• Blocking studies what happens when there are two
  CSs and a single UCS.
• When two neutral stimuli are paired with a UCS,
  one becomes a CS associated with the UCS and the
  other does not it is blocked.
• The unattended stimulus is blocked because it
  provides no new information about the UCS.
• When it provides info about intensity it is
  unblocked.

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3.14 (A) Design and (B) Results of Kamins
blocking experiment
More learning
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3.15 (A) Design and (B) Results of Kamins
unblocking experiment
For group 2, L is paired with the larger shock.
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Relative Validity

• In a situation where differential stimuli vary
  with the presence of the UCS but a third stimulus
  does not, blocking occurs (correlated condition).
• In a situation where all stimuli appear with the
  UCS the same amount of time, all three will be
  conditioned (uncorrelated condition).
• There is no blocking of any stimulus.

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3.16 Design and results of the relative
validity experiment
Less learning
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3.17 Compounded CSs are probably always present
during conditioning