Fedorchak P M, Bolles R C
J Exp Psychol Anim Behav Process. 1987 Jan;13(1):73-9.
Rats learned to associate one flavor conditioned stimulus (CS; grape or orange) with an ethanol (caloric) or saccharin (sweet but noncaloric) solution unconditioned stimulus (US), and the other flavor CS with either the other US or plain tap water. They were then given two-bottle choice tests between the flavor CSs apart from the USs. Flavors associated with 5% ethanol were preferred over saccharin-paired and water-paired flavors by sated rats, and food deprivation during the choice test enhanced this preference. The ethanol-paired flavor preference was not affected by feeding conditions (deprived vs. ad lib) during CS-US conditioning. Flavors associated with 8% sucrose (caloric + sweet tasting) were preferred over water-paired flavors during ad lib testing, and this preferences was also enhanced by food deprivation. Flavors associated with 0.028% or 0.25% saccharin were preferred over flavors paired with water; however, these preferences were not enhanced by deprivation at test time. In all cases, calorie-mediated preferences, at their highest levels, were stronger than taste-mediated preferences. These experiments indicate that preferences for flavors associated with caloric substances are positively related to hunger level at test time, but preferences mediated by a prior preferred taste are independent of test-time hunger level.
大鼠学会将一种味道条件刺激（CS；葡萄味或橙子味）与乙醇（含热量）或糖精（甜但不含热量）溶液非条件刺激（US）联系起来，另一种味道CS则与另一种US或普通自来水联系起来。然后，在不提供US的情况下，让它们在两种味道CS之间进行双瓶选择测试。饱腹的大鼠更喜欢与5%乙醇相关的味道，而不是与糖精配对和与水配对的味道，并且在选择测试期间的食物剥夺增强了这种偏好。在CS-US条件反射期间，与乙醇配对的味道偏好不受进食条件（剥夺与自由进食）的影响。在自由进食测试期间，与8%蔗糖（含热量+甜味）相关的味道比与水配对的味道更受青睐，并且这种偏好也因食物剥夺而增强。与0.028%或0.25%糖精相关的味道比与水配对的味道更受青睐；然而，这些偏好在测试时不会因剥夺而增强。在所有情况下，热量介导的偏好，在其最高水平时，比味道介导的偏好更强。这些实验表明，对与含热量物质相关味道的偏好与测试时的饥饿水平呈正相关，但由先前偏好的味道介导的偏好与测试时的饥饿水平无关。
