A BEHAVIOR SYSTEMS-APPROACH TO THE EXPRESSION OF BACKWARD ASSOCIATIONS

In the first phase of Experiment 1 rats were trained with a backward s erial conditioned stimulus (CS) with three 8-s elements (Food-Near-lnt ermediate-Far, where the name of the element denotes its temporal prox imity to food). In the second phase of this experiment, different grou ps received a novel lever presented in compound with a different CS el ement. In the first phase of Experiment 2, rats were also trained with a similar backward serial CS; but, in the second phase, the entire se rial CS was shifted to a forward pairing (Far-Intermediate-Near-Food), and again different groups received a novel lever in compound with a different CS element. In the first phase of Experiment 3, a serial CS was explicitly unpaired with food. The second phase of this experiment was identical to that of Experiment 2. The results showed that lever contact was lowest during the Near element in Experiment 1, highest du ring the same element in Experiment 2, and indistinguishable among all the elements in Experiment 3. These outcomes support the behavior sys tems hypothesis that backward CSs come to control a sequence of post-f ood search modes that can influence subsequent pre-food search. (C) 19 98 Academic Press.