Palatability Shifts in Taste and Flavour Preference Conditioning

TLDR

The study examined how flavour preference conditioning alters the palatability of tastes and flavours. Rats were subjected to reverse‑order differential conditioning with glucose or flavour CSs, and hungry rats received long‑exposure conditioning pairing flavour CSs with caloric or sweet reinforcers to assess preference and palatability changes. Rats acquired conditioned preferences for CS+ in reverse‑order conditioning, showing hedonic responses and palatability shifts when paired with glucose or flavours, but forward conditioning produced preference without palatability change, and in hungry rats CS+ was preferred regardless of association yet palatability increased only after flavour‑calorie pairing, indicating that flavour preference acquisition does not always coincide with palatability enhancement.

Abstract

Changes in palatability of tastes and flavours as a result of flavour preference conditioning were examined. In Experiment 1, when tastes were paired with glucose in a reverse-order differential conditioning paradigm, rats acquired conditioned preferences for CS + and displayed more hedonic responses to CS + than to CS − in a postconditioning taste reactivity test. In Experiment 2, rats that received oral infusions of flavours as CSs during a reverse-order conditioning procedure expressed both palatability shifts and conditioned preferences for CS + . Rats that received a forward conditioning procedure acquired a preference for CS + , but the palatability of CS + was unchanged. In Experiment 3, hungry rats drank mixtures of a flavour CS and a calorific or sweet tasting reinforcer in a long-exposure conditioning paradigm. When tested hungry, rats preferred CS + whether they had acquired flavour-calorie or flavour-taste associations. However, CS + became more palatable only for rats that acquired flavour-calorie associations. These results suggest that acquisition of flavour preferences, as measured by 2-bottle tests, may not always be accompanied by enhanced palatability.