How food preferences are learned: laboratory animal models

Abstract

Food selection represents a major challenge for omnivorous species. Faced with a variety of potential foodstuffs, many beneficial and some deleterious, the omnivore must decide which to eat and which to reject. The select-reject decision process involves an evaluation of the sensory characteristics of the foodstuff, particularly its flavour (i.e. taste, odour and texture). Innate predispositions such as a sweet-taste preference and bitter-taste aversion influence this process. With experience, animals refine their preferences as they associate the flavours of specific foods with the foods' post-ingestive consequences. Social interactions also contribute to the food choices of many animal species. Until recently, most research has focused on conditioned food aversions which readily develop when animals experience gastrointestinal malaise after eating a new food (Braveman & Bronstein, 1985). It is now well documented that strong food preferences can also be learned as animals experience the positive nutritive effects of foods. As reviewed below, a variety of models have been developed using laboratory rats to reveal the intricacies of food-preference learning. C O N D I T I O N E D F L A V O U R -P R E F E R E N C E PARADIGMSThe most common procedure used in the experimental study of acquired food preferences is the conditioned flavour-preference (CFP) paradigm. In one version of this paradigm different cue flavours (e.g. cherry and grape) are added to an energy food and a non-energy 'food' which can be in liquid or solid form. (To control for possible unlearned preferences for the specific cue flavours, the flavours paired with the energy and non-energy foods are counterbalanced across animals.) Rats are trained to consume the two flavoured foods during separate sessions to facilitate their associating the cue flavours with the post-ingestive consequences of the foods. Flavour-preference learning is then assessed in a two-choice test. In this test, the two flavours are presented in otherwise identical foods (e.g. a mixture of the energy and non-energy foods) so that any differential intakes can be attributed to a learned response to the two cue flavours. This training procedure is typically considered to be a form of Pavlovian conditioning with the nutrient being the unconditioned stimulus (US) and its associated cue flavour, the https://www.cambridge.org/core/terms. https://doi

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