Flavour-Odour Compound Conditioning: Odour-Potentiation and Flavour-Attenuation

Abstract

Five experiments employed a toxiphobia conditioning paradigm to examine the strengths of odour and flavour aversions when conditioned separately and in compound. When conditioned in compound, odour aversions were stronger than when conditioned separately, i.e., the flavour potentiated the odour (Experiment Ia), but flavour aversions were weaker than when conditioned separately, i.e., the odour attenuated the flavour (Experiment Ib). The duration of exposure to the reinforced compound governed the nature of the interaction between the components: at a brief exposure, the flavour overshadowed the odour; at a long exposure, the flavour potentiated the odour (Experiment II). The remaining experiments examined the mechanism subserving the potentiation effect. Experiment III demonstrated that extinction of the flavour associate of the odour attenuated the odour aversion but further conditioning of the flavour did not strengthen the odour aversion. Experiment IV confirmed this effect of extinction but also found a comparable attenuation of the odour aversion from extinction of a separately conditioned flavour. Experiment V examined the previous failure to influence the strength of the odour aversion by strengthening the flavour aversion. In this experiment, conditioning the flavour associate or a separately conditioned flavour with a more potent US augmented the strength of the odour aversion. The results did not provide support for the idea that the potentiation phenomenon reflects the formation of within-compound associations but did indicate that a potentiated odour aversion could be modulated by manipulations designed to alter the US representation.