Second-order excitation mediated by a backward conditioned inhibitor.
Conditioned suppression studies with rats explored the informational content of a backward conditioned inhibitor. Pairings of an unconditioned stimulus (US) and Stimulus 1 (US-->S1) established S1 as an inhibitor in Experiment 1. Pairing the inhibitor S1 with a novel S2 (S2-->S1) promoted excitatory second-order conditioning (SOC) to S2, which suggested S1 was well associated with the US. Degrading presumed S1-US associations in Experiment 2 by S1- (extinction) treatment eliminated S2's excitation while preserving S1's inhibition. Experiments 3 and 4 converged in showing that S2 was not an excitor when Pavlovian conditioned inhibition (CI) was the inhibitory treatment prior to the SOC phase, but instead acted as a second-order inhibitor. Results are discussed in relation to the temporal coding hypothesis, the SOP ("sometimes opponent process") and Rescorla-Wagner models of conditioning, and the associative structure of SOC. Also, the data suggest that backward inhibition is special and that not all forms of CI are equal.
Barnet
R C
RC
Department of Psychology, Dalhousie University, Halifax, Nova Scotia, Canada.
Miller
R R
RR
D000818:Animals; D001245:Association Learning; D003214:Conditioning, Classical; D005108:Extinction, Psychological; D005260:Female; D007266:Inhibition, Psychological; D008297:Male; D011939:Mental Recall; D051381:Rats; D017207:Rats, Sprague-Dawley