Food deprivation and conditioned flavor preferences based on sweetened and unsweetened foods

In four experiments, rats' preferences for flavors consumed under high deprivation versus low deprivation were measured. In Experiment 1, rats preferred flavors received in unsweetened food under high deprivation to flavors received in unsweetened food under low deprivation. This preference did not vary with amount of food used to deliver the flavors (1-g vs. 16-g wet mash). Sweetening the food (0.10% saccharin) eliminated this preference when 16 g of mash was received, but not when 1 g of mash was received (Experiments 2 and 3). Sweetening the mash even more (0.15% saccharin) eliminated the preference when 1 g of mash was received, as well as when 20 g of mash was received. We suggested that the reinforcing value of sweetness is reduced by increasing deprivation level.