Abstract

Taste-aversion learning has been a popular paradigm for examining associative processes because it often produces outcomes that are different from those observed in other classical conditioning paradigms. One such outcome is taste-mediated odor potentiation in which aversion conditioning with a weak odor and a strong taste results in increased or synergistic conditioning to the odor. Because this strengthened odor aversion was not anticipated by formal models of learning, investigation of taste-mediated odor potentiation was a hot topic in the 1980s. The present manuscript reviews the history of potentiation research with particular focus given to the stimuli that produce potentiation, the conditions that produce potentiation, the possible mechanism of this phenomenon, and possible reasons for the decline of research in this area. Although the number of published reports of potentiation has decreased since the 1980s, recent physiological and behavioral assessments have advanced the field considerably, and the opportunities for future research are bountiful. Recent physiological experiments, for example, have identified the basolateral nucleus of the amygdala as the key brain region to produce taste-mediated odor potentiation (e.g., Hatfield andGallagher, 1995). Also, recent behavioral experiments have extended the generality of synergistic conditioning effects. Studies have shown that odor can potentiate responding to taste (Slotnick, Westbrook and Darling, 1997) and that augmented responding can be produced in the A+/AX+blocking design (e.g., Batsell and Batson, 1999). With the current understanding of where synergistic conditioning may occur in the brain and the new tools to explore synergistic conditioning, we propose various directions for future research to determine whether taste-aversion learning and synergistic conditioning require unique explanations