Hastjarjo T, Silberberg A, Hursh S R
Department of Psychology, American University, Washington, DC 20016.
J Exp Anal Behav. 1990 Jan;53(1):155-61. doi: 10.1901/jeab.1990.53-155.
In Experiment 1, 4 rats earned their daily food ration by choosing on a trials basis between a "risky" and a "riskless" lever. The risky lever produced either 15 45-mg food pellets or no pellets, and on average provided five pellets per choice. The riskless lever always produced three pellets. Across conditions, the number of trials per session was varied. Body weight and choice of the risky lever decreased as the number of trials per session decreased, even though body weight could only be defended by increased choice of the risky lever. In Experiment 2, trials per session were fixed, but the number of pellets delivered by the risky and riskless levers was either at the same level as in Experiment 1 or tripled from those levels. Now choice of the risky lever was inversely related to the size of reinforcement and to body weight. The results of these experiments show that risk aversion covaries with the amount of food available in a session and the daily variance in the amount of food earned.
在实验1中，4只大鼠通过在“有风险”和“无风险”杠杆之间进行逐次选择来获取每日食物定量。有风险的杠杆要么产生15颗45毫克的食物颗粒，要么不产生颗粒，平均每次选择提供5颗颗粒。无风险的杠杆总是产生3颗颗粒。在不同条件下，每节实验的试验次数有所变化。随着每节实验的试验次数减少，体重和选择有风险杠杆的次数也会减少，尽管体重只能通过增加对有风险杠杆的选择来维持。在实验2中，每节实验的试验次数是固定的，但有风险和无风险杠杆提供的颗粒数量要么与实验1中的水平相同，要么是那些水平的三倍。现在，对有风险杠杆的选择与强化物的大小和体重呈负相关。这些实验的结果表明，风险厌恶与一节实验中可得食物的量以及每日获取食物量的变化相关。
