Overshadowing and Blocking

Question 1

What is successful conditioning dependent on?

Answer 1

The US mattering to the individual

The CS receiving attention

Question 2

What is the name of the model associated with CS/US pairing strength?

Answer 2

Rescorla-Wagner Model

Question 3

Is the Rescorla-Wagner model based on neural activity?

Answer 3

No - just descriptive, reflecting occurrences in empirical data.

Question 4

Describe the Rescorla-Wagner model.

Answer 4

Repeated parring of an US and CS -> gradual increase in strength of association
Growth continues until associative strength is equal to the magnitude of the value of US
Rate of growth is determined by difference between current associative strength of CS and maximum possible based on US value - difference will be large to begin but gradually decrease

Question 5

What is the equation of the Rescorla-Wagner Model?

Answer 5

Difference in V = a (L-V)
Where V = current CS-US association strength
Difference in V = change in strength on a given trial
Lamba = set by magnitude of US - reflects maximum strength CS-US association can achieve
Alpha = salience of CS (0->1)

Question 6

What is the value of V on the first experience of an US?

Answer 6

0

Question 7

What is overshadowing. When does it occur?

Answer 7

Occurs when 2 stimuli are presented together rather than sequentially
Conditioning will cease when the combined associative strength = Lambda
Therefore the presence of one CS overshadows learning the meaning of the other, and response shown to one element on its own will not be as strong.

Question 8

What is blocking? Give an eg. of a study.

Answer 8

Association already formed (Lambda = 100) so providing an additional CS does not get learned.
eg. Kamin 1969
Group 1 learns Noise predicts Shock, then presented with Light and Noise, then Light alone
Group 2 learns Light and noise predict shock, then light alone.
Only Group 2 show suppression of behaviour to avoid the shock

Question 9

What is another term for conditioned suppression?

Answer 9

Conditioned Emotional Response

Question 10

What is conditioned suppression?

Answer 10

Animal trained to perform operant response to obtain food - Pair a stimulus with onset of shock

Question 11

What is the suppression ratio?

Answer 11

a/(a+b)
where a = rate of level pressing during CS (warning tone etc.)
b = rate of level pressing prior to CS
SO ratio of 0.5 indicates no suppression (continuation of normal behaviour)

Question 12

What is most important in pairing US and CS?

Answer 12

Contingency NOT contiguity