Effect of US signal value on blocking of a CS-US association.
When an unconditioned stimulus (US) signals the delivery of a second US, there is poor conditioned responding to a conditioned stimulus (CS) that signals the second US. Using an appetitive conditioning preparation with rats, 3 experiments examined the factors that contribute to this poor conditioned responding. In Experiment 1, conditioned responding was improved when US-alone presentations came before, but not after, CS training. Experiment 2 showed that the effect in Experiment 1 was not due to context extinction, and Experiment 3 showed that context-US associations do not significantly contribute to responding in the US-US training procedure. The results show that poor conditioned responding is an acquisition deficit, arising from US, rather than context, signal value.
Goddard
M J
MJ
Department of Psychology, University of New Brunswick, Saint John, Canada.
D000818:Animals; D001070:Appetitive Behavior; D001245:Association Learning; D001288:Attention; D003214:Conditioning, Classical; D005260:Female; D011939:Mental Recall; D009042:Motivation; D051381:Rats; D017207:Rats, Sprague-Dawley