Within-compound associations mediate augmented flavor aversions

Five experiments with rat subjects explored flavor-aversion conditioning in the A+/AX+ design. In Experiment 1, odor preconditioning prior to taste+odor compound conditioning significantly strengthened a taste aversion, and taste preconditioning prior to taste+odor conditioning significantly augmented an odor aversion. Experiments 2A and 2B eliminated the alternative explanation that the augmentation effect was produced by differential exposure to the compound during conditioning. Next, we examined a possible mechanism of these augmentation effects by employing post-conditioning extinction of the augmenting stimulus (CS A); previous research had also used this technique to explore augmentation, but those studies yielded conflicting results. In both Experiments 3A and 3B, post-conditioning extinction of CS A led to a significant decrease in the strength of the augmented aversion to CS X, regardless of stimulus modality or stimulus salience. Collectively, these results suggest augmented flavor aversions are produced via within-compound associations between CS A and CS X.