6.1 Extinction Flashcards
What happens when the CS is no longer paired with the US?
Extinction - the conditioned response (CR) stops
What does the R-W model assume the value of lambda is for non-reinforcement?
0
What happens according to the R-W model, when the CS is presented without the US?
It generates a -ve discrepancy (US is expected but absent)
Lambda = 0, sigmaV = 1 (0-1) = error term
When the CS is presented without the US, what happens to deltaV and V?
DeltaV is -ve and V begins to decrease
Why does lambda normally equal 1 in examples?
Due to convenience and ease of the model
How do you work out the true value of lambda when presented with a graph?
Find the asymptote
e.g. if asymptote = 17, then lambda = 17
We take the value of 1 in examples for convenience
Does the R-W model predict extinction?
Yes
Learning (V) decreases as CS-US pairing is extinguished
What is a partial reinforcement schedule?
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
Does the R-W model predict partial reinforcement schedules well?
Yes - the way it accounts for it is similar to extinction
Explain how the R-W model predicts partial reinforcement learning
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
What does the R-W model predict for different learning schedules when they are being extinguished?
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
What is the partial reinforcement effect?
Using a partial reinforcement schedule results in resistance to extinction - the R-W model does not account for this
How does the R-W model explain extinction and what are the 3 contradictions of this?
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 and reinstatement of responding
What is spontaneous recovery?
Responding recovers to the CS simply by the passage of time
What is rapid reacquisition?
After extinction, conditioned responding to the CS is reacquired faster than before
Demonstrates that the CS-US link has not been completely erased
What is renewal?
After extinction of responding in one context, responding can be renewed if the CS is presented in a different context
What are the 3 different groups in the experiment that shows evidence for renewal?
All groups get conditioning of CS-US pairing in context A
Group 1: CS is extinguished in context A
Group 2: CS is extinguished in context B
Group 3: no extinction but presented in context B (control)
The groups are then tested in context A
What are the results for the different groups in the renewal experiment?
Group 1 are less scared of CS as it was extinguished in the context it is being tested in
Group 2 show a renewal of the fear to CS when tested in context A - CS was extinguished in B
Control still show fear as never underwent extinction
Discuss a flaw in exposure therapy related to extinction and renewal
Exposure therapy happens in the context of clinical setting and reductions in fear happen well
But when you go back to the real world, the context is diff and fear may not decrease
Good to do exposure therapy in diff environments to avoid renewal
What is reinstatement?
After extinction, responding can be reinstated if the US is presented alone
What is the explanation for extinction referring to “masking”?
Extinction is masking the original learning such that there are still some scenarios where original learning will dominate
How does Bouton explain extinction?
Bouton suggests animals acquire multiple memories of the CS
After conditioning, only memory is CS –> US
After extinction, animals have 2 different memories with conflicting content:
- memory of CS –> US
- memory of CS alone
CR is determined by which type of memory is retrieved on test
What is the key difference between Bouton’s explanation for extinction and the R-W model?
R-W model thinks of a single link between CS-US
Bouton thinks of 2 different associations: CS-US that strengthens and CS-US that weakens
What do animals use to decide which memory to retrieve (Bouton)?
Temporal and physical cues
Are memories from extinction episodes situation specific according to Bouton?
Yes - animal retrieves memories when tested in similar situation, but fails to retrieve them in different contexts or after a long time
This is why spontaneous recovery, renewal and reinstatement can occur
