The role of olfactory cues and their effects on food choice and acceptability
Food intake in humans is guided by a variety of factors, which include physiological, cultural, economic and environmental influences. The sensory attributes of food itself play a prominent role in dietary behaviour, and the roles of visual, auditory, gustatory and tactile stimuli have been extensively researched. Other than in the context of flavour, however, olfaction has received comparatively little attention in the field of food acceptability. The investigation was designed to test the hypothesis that olfactory cues, in isolation of other sensory cues, play a functional role in food choice and acceptability. Empirical studies were conducted to investigate: the effects of exposure to food odours on hunger perception; the effects of exposure to food odours with both high and low hedonic ratings on food choice, consumption and acceptability; and the application of odour exposure in a restaurant environment. Results from these studies indicated that exposure to the food odours led to a conscious perception of a shift in hunger, the direction and magnitude of which was dependent on the hedonic response to the odour. Exposure to a food odour with a high hedonic rating prior to a meal significantly increased consumption and acceptability (p<0.05), and exposure to a food odour with a low hedonic rating had no significant effect (p>0.05). When applied to a restaurant environment, exposure to a food odour with a high hedonic rating significantly influenced food choice and acceptability (p<0.05). Subject and stimulus variables, contributing to the role of olfactory cues, were identified from the results, facilitating the development of a conceptual olfactory cueing model. The model demonstrates how a series of independent variables, relating to odour exposure, may lead to either an enhancement of dietary patterns or suppression of food intake. The application and implications of the model are discussed. As such this research establishes direct links between stimulus and response in an ecologically valid environment.