Rescorla Wagner and Blocking Flashcards
what is a
learning rate parameter determined by the salience of CS;
what is B
learning rate parameter determined by the salience of the outcome
what is (upside done v with a tail)
asymptote of associative strength (V). it has a positive value on episodes when the outcome is US with its magnitude being determined by the effectiveness of US.
what is EV
sum of the associative strengths of all CSs present on the learning episode
what is (upside done v with a tail) - EV referred to as
prediction error
Bear in mind that associative strength as computed by Rescorla-Wagner does not necessarily translate directly into responding –but we usually assume that the relationship between the two is
monotonic
when does the CS perfectly predict behaviour?
Trial X= 0.5 (1-1)= 0
example of blocking
Blocking happens when you start conditioning with one US and CS pairing (e.g. above with noise and foot shock). In the second stage, a novel CS (light) is added. There will be little or no fear in response to the light alone. It has been blocked. The light does not acquire any predictive value
example of overshadowing
conditions start at the same time
what happens here:
First trial = 0.5(1-0+0)= 0.5 = each stimulus gets 0.5
On the next trial, there is no more learning. They both stay with their 0.5 predictive strengths.
what does Beckers et al experiment 1 show
Experiment 1 demonstrated that under circumstances that result in robust blocking after irrelevant pretraining treatment, explicit exposure to subadditivity during pretraining effectively abolishes blocking
what does Beckers et al experiment 3 show
Experiment 3 demonstrated that blocking is obtained more readily if the blocking procedure involves a shock intensity that is submaximal than if the blocking procedure involves the most intense shock intensity that animals have ever experienced, independent of the absolute intensity of the shock.
