Time Discounting: The Concavity of Time Discount Function:<BR>An Experimental Study
Time Discounting: The Concavity of Time Discount Function:<BR>An Experimental Study
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时间折扣：时间折扣函数的凹性：<BR>实验研究
DOI：
10.11167/jbef.5.2
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发表时间：
2012
期刊：
影响因子：
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通讯作者：
Kan Takeuchi
中科院分区：
文献类型：
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作者：
Toyotaka Sakai;Toyotaka Sakai;坂井豊貴;坂井豊貴;坂井豊貴;坂井豊貴;坂井豊貴;古瀬 啓之;古瀬啓之;大津敬介;Kan Takeuchi
本文研究了时间折扣函数的性质。37名受试者的实验提供了支持反S形时间折扣函数而不是双曲（和凸）时间折扣函数的证据。如果时间折扣函数在t附近是凹的，则决策者存在未来偏差，但由于不容易识别，因此在文献中很少有关于未来偏差的报道。时间偏好的实验通常让受试者比较两个（延迟）支付选项，并调整其中一个选项的奖励水平，使受试者在两个选项之间无差异。为了检测未来偏差，在这项研究中，我调整了支付的时间，而不是奖励金额。这种新的启发方法也独立于现有实验中常见的混杂因素。具体地说，该方法没有对效用函数的形式做任何假设，也没有假设时间和报酬是可分离的。这个优势使我们能够更精确地估计时间偏好。
This paper examines the concavity of time discount function. The experiment with 37 subjects provides the evidence in favor of an inverse S-shaped time discount function rather than a hyperbolic (and convex) time discount function. If time discount function is concave around t, then the decision-maker exhibits future bias.Future bias has seldom been reported in the literature, since it is not easily identified. Experiments on time preference commonly let subjects compare two (delayed) payment options and adjust the reward level of one option to make the subject be indifferent between the two options. To detect future bias, in this study, I adjust the timing of the payment instead of the reward amount. This new elicitation method is also independent of the confounding factors that are common in the existing experiments. Specifically, the method does not put any assumption on the form of utility function and does not assume that time and reward are separable either. This advantage enables us to estimate time preference more precisely.