Conditioned flavor preferences: evaluating postingestive reinforcement by nutrients.

The acceptance of food and the expression of preferences for particular foods have both innate and learned components. To determine the mechanism(s) responsible for the acquisition of learned preferences and the enhancement of inborn taste preferences, it is important to separate the component stimuli: the oral flavor cues and the postingestive nutrient cues that are associated with the flavors. Unambiguous analysis of postingestive reinforcement of a nutrient requires post-oral presentation of the nutrient during or after oral intake of the flavor stimulus. This protocol concentrates on controlling stimulus presentation in associative conditioning, pairing a flavor with positive postingestive effects.