The present study explored bidirectional excitatory conditioning using
the behavior systems assumption that conditioned responding is relate
d to a sequence of search modes preceding and following the unconditio
ned stimulus. In Experiment 1a, rats were initially trained with eithe
r 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-BC
SI-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 fol
lowed 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 fo
r expression with lever-directed responding in the compound condition.
The results suggested several advantages of analyzing Pavlovian condi
tioning within a behavior systems framework. (C) 1996 Academic Press,
Inc.