Differential effects of omission contingencies on various components of Pavlovian appetitive conditioned responding in rats

Five experiments with a total of 120 male Sprague-Dawley rats investigated the effects of omission and partial reinforcement contingencies on 5 individual behaviors (rearing, magazine, perambulation, head jerk, and startle) evoked by visual and auditory CSs paired with a food UCS. The effects of omission depended on the behavior on which that contingency was placed: One behavior was eliminated, one was unaffected, and 3 were reduced relative to the performance of yoked controls. Partial reinforcement resulted in lower frequencies of 3 behaviors and higher frequencies of 2 behaviors, compared with performance under consistent reinforcement. A partial reinforcement extinction effect was noted with one behavior but not with the others. These results are related to the possible role of instrumental conditioning contingencies in generating conditioned behavior in this appetitive conditioning preparation and to the independence of individual components of a complex CR. (PsycINFO Database Record (c) 2006 APA, all rights reserved).