Augmentation's boundary conditions? Investigation of spatial contiguity, temporal contiguity, and target flavor familiarity

When a preconditioned flavor (A) is conditioned in compound with a novel target flavor (X), the aversion to the target X is increased; this enhanced aversion to X is called augmentation. In 6 experiments with rat subjects, we manipulated the spatial contiguity of cues during compound conditioning (AX+), the temporal contiguity of cues during compound conditioning (AX+), and the familiarity of the target. In all 6 studies, augmentation was recorded with spatially separated flavors. In Experiments 2-4, augmentation was not detected if the two flavors were temporally discontiguous, but augmentation still occurred if the cues were partially contiguous (i.e., the flavors co-occurred for 2 min of a 4-min exposure). Even though stimulus preexposure can often weaken subsequent conditioning, augmentation was observed following 1 or 4 preexposures to the target taste (Experiment 5A) or target odor (Experiment 5B). In sum, manipulations that should weaken, but not eliminate, the within-compound association formed during AX+ conditioning did not prevent augmentation, suggesting the robustness of the within-compound association when one of the elements is a preconditioned flavor.