Animal studies on the meta choice behavior under uncertainty

“Meta”选择是在两个选择情境中的选择，每个情境都由一些备选方案组成。“自由”与“被迫”选择实验是Meta选择的一个恰当例子。在这样的实验中，被试在第一阶段从两个情境中选择一个，然后在第二阶段在自由选择情境中从多个备选方案中选择一个，或者在强制选择情境中强制选择一个备选方案。对任何替代方案的反应都会导致相同的结果。在项目1中，我们在1996年使用并发链时间表在四只鸽子中测试这种类型的Meta选择。虽然先前的研究结果预测鸽子在通常的设置中更喜欢自由侧而不是强迫侧，但在延迟强化的某些设置中不喜欢自由侧，我们甚至在延迟强化条件下和在自由选择情况下将灭绝时间表添加到其中一个选项的条件下也没有发现这种一致的偏好。我们在1997年详细阐述了我们的程序，如Stubbs & Pliskoff方法的应用，并使用概率加固代替延迟加固。如果强化概率（Pr）为1，7只鸽子更喜欢自由侧一点，但没有一致的偏好，如果Pr不是1。当自由选择情境中的一种方案的Pr部分减少时，他们表现出风险厌恶。在项目2中，我们试图评估“对变化的抵制”，作为一种新的选择偏好的衡量标准。比较由FI和VI组成的多链方案和并行链方案，发现后者的响应率更高，对VI变化的抵抗力更强。

A "meta" choice is a choice between two choice situations, each of which are consisted of some alternatives. The "free" versus "forced" choice experiment is one of appropriate examples of the meta choice. In such an experiment, subjects choose one of two situations in the first stage, then they choose one of multiple alternatives in the free choice situation or choose forcefully single alternative in the forced choice situation in the second stage. Responses to any alternatives result to the same outcomes. In Project 1, we used the concurrent-chains schedule for testing this type of the meta choice in four pigeons in 1996. Although previous results predicted that pigeons preferred the free to the forced side in the usual settings but not preferred the free side in some settings under delayd reinforcement, we could not find such consistent preference even in the delayd reinforcement condition and in the condition which added the extinction schedule to one of alternatives in the free choice situation. We elaborated our procedures in 1997, such as application of Stubbs & Pliskoff method, and used probabilistic reinforcement instead of delayd reinforcement. Seven pigeons preferred the free side a little if the reinforcement probability (Pr) was one, but showed no consistent preference if Pr was not one. They showed risk averse when Pr of one alternative in the free choice situation partly decreased. In Project 2, we tried to evaluate "resistance to change" as a new measure of preference between alternatives. Compared the concurrent-chains schedule to the multiple-chains schedule, both were consisted of FI and VI with same interval values, we observed higher response rate and stronger resistance to change in VI only in the latter schedule.