Bauman R A, Raslear T G, Hursh S R, Shurtleff D, Simmons L
Department of Neurobehavioral Assessment, Walter Reed Army Institute of Research, Washington, DC 20307-5100, USA.
J Exp Anal Behav. 1996 Mar;65(2):401-22. doi: 10.1901/jeab.1996.65-401.
Three experiments were conducted to study the effect of an imperfect substitute for food on demand for food in a closed economy. In Experiments 1 and 2, rats pressed a lever for their entire daily food ration, and a fixed ratio of presses was required for each food pellet. In both experiments, the fixed ratio was held constant during a daily session but was increased between sessions. The fixed ratio was increased over a series of daily sessions once in the absence of concurrently available sucrose and again when sucrose pellets were freely available. For both series, increases in the fixed ratio reduced food intake, but body weight was reduced only in the no-sucrose condition. In the sucrose condition, body weight and total caloric intake (sucrose plus food) were relatively unaffected by increases in the fixed ratio. At all fixed ratios, food intake was proportionally reduced by the intake of sucrose. In Experiment 3, monkeys obtained food or saccharin by pressing keys; the fixed ratio of presses per food pellet was increased once when tap water was each monkey's only source of fluid, again when each monkey's water was sweetened with saccharin, and a third time when each monkey had concurrent access to the saccharin solution and plain water. Increases in the fixed ratio, but not the intake of the saccharin solution, reduced each monkey's food intake. Because neither rats' sucrose nor monkeys' saccharin intakes affected the slope of the respective demand curves for food, monkeys and rats increased their daily output of presses and thereby defended their daily intake of those complementary elements of food. However, sucrose reduced rats' food intake. The relative constancy of body weight and total caloric intake in the sucrose condition is consistent with the possibility that rats tended to regulate caloric intake.
进行了三项实验，以研究在封闭经济中，一种不完全的食物替代品对食物需求的影响。在实验1和实验2中，大鼠按压杠杆获取其每日全部食物定量，每颗食物颗粒需要固定的按压次数。在这两项实验中，每日实验时段内固定比例保持不变，但在不同时段之间会增加。在没有同时提供蔗糖以及蔗糖颗粒可自由获取这两种情况下，固定比例在一系列每日实验时段中都有所增加。对于这两个系列，固定比例的增加都减少了食物摄入量，但仅在无蔗糖条件下体重有所下降。在有蔗糖的条件下，体重和总热量摄入（蔗糖加食物）相对不受固定比例增加的影响。在所有固定比例下，蔗糖的摄入按比例减少了食物摄入量。在实验3中，猴子通过按键获取食物或糖精；当自来水是每只猴子唯一的液体来源时，每颗食物颗粒的固定按压比例增加一次，当每只猴子的水用糖精调味时再次增加，当每只猴子可以同时获取糖精溶液和普通水时第三次增加。固定比例的增加而非糖精溶液的摄入减少了每只猴子的食物摄入量。因为大鼠的蔗糖摄入和猴子的糖精摄入都没有影响各自食物需求曲线的斜率，所以猴子和大鼠增加了它们每日的按压次数，从而维持了它们对那些食物补充成分的每日摄入量。然而，蔗糖减少了大鼠的食物摄入量。在有蔗糖条件下体重和总热量摄入的相对稳定性与大鼠倾向于调节热量摄入的可能性是一致的。
