Associative history, not familiarity, determines strength of taste-aversion conditioning in thiamine-deficient rats

Abstract

Two groups of rats (the recovery groups) were fed on a synthetic thiamine-deficient diet, and another group (the supplemented group) was fed on the same diet but received supplemental thiamine in their water so as not to become deficient. Following a 6-day recovery period during which all rats were given a novel-flavored thiamine-enriched diet, one recovery group and the supplemented group received injections of lithium chloride, and the remaining recovery group received injections of saline. Although all groups consumed similar amounts of the chocolate-enriched diet during the recovery period (i.e., all groups were approximately equally familiar with the enriched diet), only the supplemented/poisoned rats showed a marked taste aversion. These results confirm the existence of a “familiar-positive” class of foods and suggest that the context in which a rat is made familiar with dietary choice may overshadow the role of familarity per se as the determining factor in the development of food aversions and preferences.