A behavior systems approach to bidirectional excitatory serial conditioning

The present study explored bidirectional excitatory conditioning using the behavior systems assumption that conditioned responding is related to a sequence of search modes preceding and following the unconditioned stimulus. In Experiment 1a, rats were initially trained with either a forward serial conditioned stimulus (CS) (FCSF-FCSI-FCSN-Food; the subscripts F, I, and N denote, respectively, elements temporally Far, Intermediate, and Near to food) or a backward serial CS (Food-BCSN-BCSI-BCSF). In Experiment 1b, all rats received one of the 8-s elements of the serial CS compounded with presentation of a novel lever and followed by food. Both forward and backward procedures produced evidence that the elements of the serial CS differentially controlled types of search mode. The forward but not the backward procedure also provided evidence for the conditioning of specific responses, which competed for expression with lever-directed responding in the compound condition. The results suggested several advantages of analyzing Pavlovian conditioning within a behavior systems framework. (C) 1996 Academic Press, Inc.