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Psyc 2330 Final > Lecture 3 > Flashcards

Lecture 3 Flashcards

1
Q

What is the rescorla-wagner model?

A

mathematical expression of surprise
- learning will occur only when the subject is surprised - that is, when what happens is different from what the subject expected to happen

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2
Q

What is blocking?

A

Participants are not surprised because they’ve already learned that the light predicts the shock
- doesn’t produce a stronger conditioned stimuli but refers to the lack of responses to the second stimulus in phase 2

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3
Q

Explain the steps involved in blocking

A

Phase 1.
Blocking: L–> US
Control: nothing

Phase 2.
Blocking: L & T –> US
Control: L & T –> US

TEST:
Blocking: no CR
Control: CR

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4
Q

Why is the blocking experiment important?

A

Shows that:

  • conditioning is not an automatic result of CS-US pairings
  • for conditioning to occur, the CS must be informative and US surprising
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5
Q

What can we use to quantify the level of surprise?

A

deltaV = Vmax - Vn
where:
V = associative strength between CS and US
Vmax = maximum associative strength
delta V = change in associative strength on each conditioning trial

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6
Q

When does the most amount of learning occur?

A

delta V

  • at the beginning of conditioning
  • -> more surprised by the US at this time
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7
Q

Why do we care how surprising the US is?

A

So we can predict what is biologically meaningful

- and we can learn to avoid or work for these

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8
Q

Learning curves differ in terms of?

A

Vmax and rate of acquisition

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9
Q

How does Vmax differ in learning curves?

A
  • asymptote level can change - determined by magnitude of US

- more incentive = higher Vmax

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10
Q

How does rate of acquisition vary between learning curves?

A
  • gradual = little learning over certain amount of time

- steep = learning is almost immediate (e.g. food avoidance)

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11
Q

What is alpha related to?

A

the importance of the CS

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12
Q

What is beta related to?

A

the importance of the US

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13
Q

Which values change with conditioning?

A

Vn and deltaV

  • Vn gets bigger
  • delta V gets smaller
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14
Q

Formula for acquisition of a conditioned response

A

deltaVn = alphabeta(Vmax-sumofVn)

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15
Q

What is the extinction of a conditioned response

A

the weakening of a conditioned response when a CS is presented by itself
- Vmax = 0

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16
Q

What type of associative strength do conditioned inhibitors have?

A

negative

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17
Q

Explain blocking using Rescorla-wagner model

A
  • when 2 CSs are used, the association or expectation at the beginning of the trial would be the sum the strengths of each stimuli present
  • therefore the amount of conditioning on a compound trial in which A and B occur together would be:

= alphabeta(Vmax-sumVofA&B)

  • the shock stays the same, therefore so does Vmax in compound conditioning (V= sum of light and tone = 1)
  • change in learning as a result of extra conditioning trial with new tone but same light, new learning = 0
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18
Q

In blocking - what if the US is different in compound conditioning?

A

Then learning would happen - if US is bigger = Vmax will be bigger

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19
Q

Explain the over-expectation effect

A
  1. tone –> shock
  2. light –> shock
  3. tone + light –> shock
  • US doesn’t change, animal will predict something that doesn’t happen (over-expected shock to occur)
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20
Q

Assume only a few trials were given before the compound trial, what is the result?

A

the model predicts an increase in associative strength for both T and L when presented during the compound trial

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21
Q

What if there is extensive training prior to the compound trial?

A

the model predicts a decrease in associative strength for both T and L when presented during the compound trial

22
Q

Explain compound training in rats (tone and light –> shock)

A

Phase 1.
experimental group: tone + light –> shock
control: nothing

Phase 2.
both groups: tone –> shock; light –> shock

= much more fear associated with light

23
Q

Why is there more fear associated with shock and light rather than shock and tone?

A

More natural to associated foot shock with a light

24
Q

What would the result be in the US is not contingent with the CS?

A

conditioning will be strong to contextual cues but not to the CS

25
Q

Explain contextual association

A

trial 1. CS + context –> US = positive associative strength to compound
trial 2. context alone –> US = positive associative strength to context
trial 20. CS + context –> US = negative associative strength to compound
trial 21. context alone –> US = positive associative strength to context

= at first, fear to both but as conditioning continues, fear to CS decreases and fear to context increases to Vmax
- CS becomes a poor predictor of US

26
Q

Some problems with Rescorla-Wagner Model:

A
  1. exclusive focus on the “surprisingness” of the US

2. the conclusion that extinction removes the original learning

27
Q

What is spontaneous recovery?

A

the reappearance of a CR to a CS after a period of time following the last extinction trial

28
Q

What is renewal?

A

the reappearance of a CR to a CS due to the return of the training environment, instead of the environment used during extinction

29
Q

What is reinstatement?

A

the reappearance of a CR to a CS due to a brief presentation of the US
- potato chip effect (just a little taste)

30
Q

What is rapid reacquisition?

A

rapid return of a CR to a previously extinguished CS (reason associated with relapse)
- something that is learned initially comes back so much faster the second time around

31
Q

What is prediction error?

A

Learning

- gets smaller with conditioning trials

32
Q

What is dopamine?

A

a neurotransmitter involved in learning motivation and a variety of psychobiological functions

33
Q

Dopamine agonist

A

blocks the reuptake of dopamine –> enhance effects

- “more”

34
Q

Dopamine antagonist

A

blocks the effect of dopamine –> removal of dopamine effects
- “less”

35
Q

Who studied stimulation of the VTA in chimps?

A

Wolfram Schultz

36
Q

Prior to CS-US conditioning:

A

no prediction; reward occurs

37
Q

After CS-US conditioning:

A

reward predicted; reward occurs

- no response at reward, but shifts to CS

38
Q

During extinction:

A

reward predicted; reward does not occur

- silencing of herons = computing prediction error

39
Q

What is auto-shaping?

A

CS associated with the delivery of a US

  • Sign tracking
  • goal tracking
40
Q

Explain sign tracking

A
  • pays attention to CS
  • response towards US declines
  • dopamine shifts activity (US –> CS)
    E.g. rat goes toward light
41
Q

Explain goal tracking

A
  • not learning predictor of US
  • fails to respond to CS
    E.g. rat going towards where food is delivered
42
Q

Response of dopamine - when is a stimulus pleasurable?

A

Only when it isn’t predicted

43
Q

Dopamine acts as the?

A

learning signal

- not the actual learning

44
Q

What region receives dopamine from VTA?

A

nucleus accumbens

45
Q

Which of the following about dopamine is false?

  • it plays a role in the acquisition of CS-US associations
  • it encodes prediction error
  • it is increased by pleasurable stimuli
  • it is released in the nucleus accumbent during CS-US learning
A

it is increased by pleasurable stimuli

46
Q

In autoshaping?

A

the CS is associated with the delivery of the US

47
Q

Activity of dopaminergic neurons in the ventral segmental area should increase when a:

A

a well conditioned CS is present

48
Q

Extinction is?

A

the acquisition of competing or alternative learning

49
Q

Rats in the random group described by Rescorla:

A

associate the US with background/contextual cues

50
Q

Assuming alpha/beta = 1 and V5 = 1, the value of deltaV after the first extinction trial is?

A

-1

51
Q

According to the rescorla-wagner model, whether conditioning will occur or not depends on the relationship between?

A

Vn and Vmax

52
Q

The blocking phenomenon is said to occur when?

A

nothing is learned about a novel stimulus despite compound training with an established excitatory CS

Psyc 2330 Final (11 decks)

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