Case D A, Nichols P, Fantino E
Department of Psychology, University of California, San Diego, La Jolla 92093-0109, USA.
J Exp Anal Behav. 1995 Nov;64(3):299-311. doi: 10.1901/jeab.1995.64-299.
Water budget of pigeons was varied to assess the dependence of risk-sensitive preferences upon economic context such as has been reported for energy-budget manipulations with small animals in behavioral ecology research. Fixed- and variable-interval terminal-link water schedules reinforced choice between equal variable-interval initial-link schedules arranged on two pecking keys. While keeping a severely restrictive budget the same across three phases of the experiment, a contrasting distinct ample budget was arranged in each. To mimic typical methods in behavioral ecology studies, in each ample budget a more than three-fold increase in amount of water per reinforcer presentation was instituted simultaneously with significantly increased overall access to water. Total choice response rates plummeted in the ample budgets, and body weights either increased significantly or remained unchanged in different phases as expected by the nature of the different manipulations. Clear preferences for the variable-interval schedule were found throughout the experiment, except for rare instances of key bias. The results agree with similar operant food-reinforcement studies and extend conditions under which risk preference apparently does not depend upon economic context.
改变鸽子的水预算，以评估风险敏感偏好对经济背景的依赖性，这与行为生态学研究中对小型动物能量预算操纵的报道类似。固定间隔和可变间隔的终端链接水时间表强化了在两个啄键上安排的相等可变间隔初始链接时间表之间的选择。在实验的三个阶段保持相同的严格限制预算的同时，每个阶段安排了一个对比鲜明的充足预算。为了模仿行为生态学研究中的典型方法，在每个充足预算中，每次强化物呈现的水量增加了三倍多，同时总体水摄入量显著增加。在充足预算下，总选择反应率大幅下降，不同阶段的体重根据不同操作的性质显著增加或保持不变。除了罕见的按键偏差情况外，在整个实验中都发现了对可变间隔时间表的明显偏好。结果与类似的操作性食物强化研究一致，并扩展了风险偏好显然不依赖于经济背景的条件。
