L10 - Variations in processing the US

Question 1

What is the equation for the RWM

Answer 1

(triangle V) = a + B X (Lamda - Sum V)

Question 2

(Triangle V)

Answer 2

Amount of learning, change in the CS-US association

Question 3

Lamda

Answer 3

Experience of US presentation

How much learning can be supported to the US

Question 4

V

Answer 4

how much a subject know about relationship between CS and US

Question 5

Sum (V)

Answer 5

Expectation of US, based on total associated strength of all CSs present

How much can be predicted from what you know about all of the CSs present

Question 6

a

Answer 6

salience of CS

Question 7

B

Answer 7

salience of US

Question 8

a and B are

Answer 8

Parameters that regulate the rate of conditioning (otherwise all conditioning would be done in one trial)

Question 9

With Learning Sigma V and lamda are always what on the first trial?

Answer 9

0 and 1

Question 10

Why bother with a numerical formula?

Answer 10

• If we have a very clearly laid out model it allows us to make PREDICTIONS
• Can design experiments and see if empirical findings match predictions of the model
• It is testable

Question 11

What does reaches an asymptote mean?

Answer 11

closer to a value of 1

Question 12

Across trial what happens to associative strength and increments in V

Answer 12

Associative strength (V) increases but increments in V get ever smaller

Question 13

Overshadowing with RWM

Answer 13

Limited amount of learning possible, two CSs share V

The CS with the larger alpha takes larger lamda proportion per trial, leaving less for other CS

If one is more salient than the other, it will take more of “the pie”

Question 14

Blocking with RWM

Answer 14

Pre-trained CS starts with high V

Already large sigma V before C2 is added

Change in V is small on each trial with added CS

The pre-trained CS has already taken a large amount of the pie, so less available to be shared between it and the new CS

Question 15

Relative signal Validity with RWM

Answer 15

Extra conditioning trials with L alone means V of L increases faster and blocks conditioning to T

Question 16

RWM explaining the truly random design

Answer 16

How the RW model explains the truly random design

- We get good conditioning when US is followed by CS
- Very bad when extra random ones happen

It isn’t that rats learn nothing just they learn the context that predicts the occurrence of the shocks, not linked to US

Question 17

The role of context in conditioning

Answer 17

The context (i.e. physical chamber) can function as an ever-present CS.

I.e the animals believe I will get shocked because I am in this box

Question 18

What does it mean when the lamda - sigma V gets smaller?

Answer 18

The associative strength (V) increases across trials, but increments in V get even smaller, learning is decelerated

Question 19

Oding-Smee (1975) black box experiement

Answer 19

Showed that extra “unsignalled” US presentation caused considerable conditioning to context

Question 20

How to prevent the animal associating to the context?

Answer 20

Durlach’s (1983) demonstrated that signalling extra USs with another CS can rescue conditioning to target CS.

Plug in a different stimulus as well (e.g. tone and light) to prevent the animal relating it to the context as most of the attention will be focused on the light - you are restoring conditioning to the tone and light and diminishing what is learnt about the context.

Question 21

How do we quantify the no of magazine entries by the rat in a Skinner box?

Answer 21

Every time the rat pokes his head into the magazine, breaks the infra-red beam and quantifies the no of magazine entries

Can think about this as the amount of expectation the rat has about when food is going to be delivered

Question 22

What did Odling-Smee use in his experiment and why?

Answer 22

Place preference chamber
Rats like more time in the black chamber because they are nocturnal animals

Can treat this as a context
Design an experiment where we vary the contingency of the tone shock association in the black chamber

Allows us to reveal how much is learned to the tone and how much is learned to the context

Question 23

What did Odling-Smee do to 6/8 conditions in the experiment?

Answer 23

Varied the proportions of contingency between US and CS

Depending on the proportion results in how many times the CS-US pairing occurs in the black chamber

Question 24

What happened to the rats when they had high proportion of CS-US pairing?

Answer 24

High proportion of CS-US pairing, learn the tone predicts the CS and move out for the shock but still spend most time in black box

Do not associate the US with the context, associate it with the CS

Question 25

What happened to the rats who had more shocks delivered in the absence of the CS?

Answer 25

Appropriately, less time is spent in the black chamber indicating that the rats are learning that the context should be feared

The US’s are non-contingent on the tone

Question 26

What did Odling-Smee do to the control groups?

Answer 26

2 control groups
received either CSs
without USs, or
USs without CSs.