L11 - Extinction

Question 1

What happens when the CS is no longer paired with the US?

Answer 1

Extinction - the conditioned response (CR) stops

Question 2

What does the R-W model assume the value of lambda is for non-reinforcement?

Answer 2

0

Question 3

What happens according to the R-W model, when the CS is presented without the US?

Answer 3

It generates a -ve discrepancy (US is expected but absent)

Lambda = 0, sigmaV = 1 
(0-1) = error term

Question 4

When the CS is presented without the US, what happens to deltaV and V?

Answer 4

DeltaV is -ve and V begins to decrease

Question 5

Why does lambda normally equal 1 in examples?

Answer 5

Due to convenience and ease of the model

Question 6

How do you work out the true value of lambda when presented with a graph?

Answer 6

Find the asymptote
e.g. if asymptote = 17, then lambda = 17

We take the value of 1 in examples for convenience

Question 7

Does the R-W model predict extinction?

Answer 7

Yes

Learning (V) decreases as CS-US pairing is extinguished

Question 8

What is a partial reinforcement schedule?

Answer 8

The CS and the US are not always followed by each other - only partially reinforced

Under reinforcement schedule of 100% - every time CS is presented, followed by US

Under partial rft schedule of 50% - on 50% of time CS is presented, followed by US

Question 9

Does the R-W model predict partial reinforcement schedules well?

Answer 9

Yes - the way it accounts for it is similar to extinction

Question 10

Explain how the R-W model predicts partial reinforcement learning

Answer 10

R-W predicts a reduction in associative strength similar to extinction when the CS is not always followed by the US - this is because deltaV is -ve

Partial reinforcement schedules show a lower asymptote for learning

Question 11

What does the R-W model predict for different learning schedules when they are being extinguished?

Answer 11

It predicts the highest asymptote takes the longest to decrease (i.e. continuous takes longer than partial because 100% is higher than 50%).

This is incorrect

Question 12

What is the partial reinforcement effect?

Answer 12

Using a partial reinforcement schedule results in resistance to extinction - the R-W model does not account for this

Question 13

How does the R-W model explain extinction and what are the 4 contradictions of this?

Answer 13

Explains it as unlearning the CS-US pairing, as if we are erasing the link

However, there are conditions that produce a recovery in responding following extinction:

Spontaneous recovery
Rapid reacquisition
Renewal
reinstatement of responding

Question 14

What is spontaneous recovery?

Answer 14

Responding recovers to the CS simply by the passage of time

Question 15

What is rapid reacquisition?

Answer 15

After extinction, conditioned responding to the CS is reacquired faster than before

Demonstrates that the CS-US link has not been completely erased

Question 16

What is renewal?

Answer 16

After extinction of responding in one context, responding can be renewed if the CS is presented in a different context

Question 17

What are the 3 different groups in the experiment that shows evidence for renewal?

Bouton and King (1983)

Answer 17

3 groups: All conditioned by a CS to a US

All learn in context A

First group: CS is extinguished in context A

Second group: CS is extinguished in context B

Control: not extinguished at all but is presented in context B

1-2 different in context
2-3 different in extinction

Question 18

What are the results for the different groups in the renewal experiment?

Answer 18

After the initial conditioning suppression is high after the tone.

Gradually throughout extinction group A become less scared

Group B: RECOVERY OF FEAR IN CONTEXT WHERE IT WASN’T EXTINGUISHED

Control scared the whole time

Question 19

What is reinstatement?

Answer 19

After extinction, responding can be reinstated if the US is presented alone

Reminder of the shock is enough to scare the CS

Question 20

What is the explanation for extinction referring to “masking”?

Answer 20

Extinction is new learning about the CS that masks the original learning (but otherwise leaves it intact)

Question 21

How does Bouton explain extinction?

Answer 21

Suggests animals acquire memories of the CS, not just a single memory but MULTIPLE

Question 22

What is the key difference between Bouton’s explanation for extinction and the R-W model?

Answer 22

RW see it as single, Bouton sees it as different associations

After extinction, animals have 2 different memories with conflicting context

1. memory of CS-US
2. memory of CS alone (enters unambiguous state - remember second memory in that context)

Question 23

What do animals use to decide which memory to retrieve (Bouton)?

Answer 23

They remember the second memory in that context.

The animals are using temporal and visual cues to decide which memory to retrieve

Question 24

Are memories from extinction episodes situation specific according to Bouton?

Answer 24

Yes, they rely on the time and environment.

Under different context you will retrieve appropriate memory.