Potentiation rather than overshadowing in flavor-aversion learning: an analysis in terms of within-compound associations.

Five experiments investigated the development of aversions to stimuli with strong odor components. Those odors were presented simultaneously with tastes are followed by lithium chloride. Contrary to expectations derived from previous investigations of compound conditioning, the presence of a taste stimulus at the time of conditioning was found to potentiate rather than overshadow the resulting odor aversions. Explanations in terms of either the taste's unconditioned aversiveness or nonassociative effects were found to be inadequate. An alternative interpretation attributing potentiation to the summed effects of within-compound odor-taste associations and odor-unconditioned stimulus associations was suggested. In agreement with such an interpretation, evidence of odor-taste associations was found in this situation. Furthermore, continued aversiveness of the taste was necessary for potentiation of the odor aversion to occur. An account of potentiation in terms of within-compound associations makes the phenomenon compatible with modern theories of Pavlovian associations.