Collaborative Research: Models of Unawareness and Ambiguity

合作研究：无意识和模糊性模型

• 批准号: 0550224
• 负责人: David Ahn
• 金额: --
• 依托单位: University of California-Berkeley
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-03-01 至 2011-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0550224&HistoricalAwards=false
• 关键词: Collaborative; Research; Models; Unawareness; Ambiguity

This study of unawareness and ambiguity has three components. First, a model is development, where implicit information is embedded in the description of an act. For example, if a consumer is offered a warranty that provides $500 in case her tires disintegrate, she is made aware that such a contingency is possible. Given this recognition, the way a contract frames the states of the world becomes important. The model complements prospect theory, which considers the framing of consequences, by considering the framing of states. The choice objects of the model are lists of contingencies and payments. This model provides two technical innovations to the theory of awareness. First, the decision maker's awareness is identified by her preferences over standard bets. Therefore, unawareness is associated with concepts of likelihood and probability rather than with knowledge and truth. This allows for partial awareness of her own unawareness. The explicit axiomatic approach also allows the analyst to predict how the decision maker will behave given a particular level of awareness from her preferences with other levels of awareness. Second, unawareness is defined over partitions of the entire state space, rather than over particular states. Then the decision maker can be aware of an event without being aware of its sub-events. For example, she can be aware that her transmission can fail, without listing all the specific components in her transmission that might break.The second component of the study formulates a representation of ambiguity where the decision maker has a second order belief on the set of priors that is possibly nonlinearly aggregated. The existence of ambiguity is modeled by the spread of her second order belief while the attitude towards ambiguity is modeled by the curvature of the aggregator. Existing characterizations of this utility assume an exogenous product structure on the state space. For example, in a resent study, Klibanoff, Marinacci, and Mukerji assume that the second dimension of uncertainty is over the priors on the first dimension. This is especially troubling for providing f oundations, because the very concept of a prior is a decisional theoretical construct, like a discount factor or an Arrow-Pratt measure. This project attempts to disentangle the theory from such exogenous structure, identifying the representation from preference over direct bets on the states. An interesting procedure is presented for identifying the second order belief and the aggregator from first order preferences, which should yield a full characterization.In the final part of the study, an experiment designed to estimate the parameters of this representation for ambiguity. It uses a novel graphical choice-theoretic design that provides enough data to confidently calibrate parameters, rather than simply test hypotheses. Such an estimate would be eminently useful in empirical applications.The broader impact of this study is that both theories are especially conducive for applications. The model of unawareness developed here is constructed in the spirit of standard subjective models to facilitate its use. It keeps standard acts and contracts as its primitives. In fact, actual contracts are often communicated as lists of contingencies and payments. The representation of ambiguity allows separate comparative statics for the existence and aversion to ambiguity. Moreover, these comparative statics carry much of the intuition in standard risk theory. By providing foundations for such a representation, these techniques can be used confidently. In addition, the measurement device outlined here is of independent interest because it provides a general method to infer ambiguity aversion from a sparse amount of "local" data. The experimental calibration of ambiguity aversion provides a useful estimate to identify other empirical models that incorporate ambiguity aversion, in the same way that an estimate of the Arrow-Pratt measure helps to identify empirical models that incorporate risk aversion.

本研究的无意识和歧义有三个组成部分。 首先，模型是发展，其中隐含的信息嵌入在对行为的描述中。 例如，如果消费者被提供了一个保修，提供500美元的情况下，她的轮胎解体，她意识到这种意外是可能的。 有了这种认识，契约如何界定世界各国就变得很重要。 该模型补充了前景理论，其中考虑到框架的后果，考虑框架的国家。 该模型的选择对象是或有事项和付款清单。该模型为意识理论提供了两个技术创新。 首先，决策者的意识是通过她对标准赌注的偏好来识别的。 因此，无意识与可能性和概率的概念有关，而不是与知识和真理有关。 这允许她对自己的无意识有部分的意识。 显式公理化方法还允许分析师预测决策者在给定特定意识水平的情况下将如何从她对其他意识水平的偏好中表现出来。 其次，无意识是在整个状态空间的分区上定义的，而不是在特定的状态上。 然后，决策者可以知道一个事件，而不知道其子事件。 例如，她可以意识到，她的传输可能会失败，没有列出所有的具体组件在她的传输，可能break.The研究的第二个组成部分制定了一个代表性的模糊性，决策者有一个二阶的信念，可能是非线性聚合的先验集。 歧义的存在是由她的二阶信念的传播建模，而对歧义的态度是由聚合器的曲率建模。 现有的这种效用的特征假设状态空间上的外生产品结构。 例如，在最近的一项研究中，Klibanoff，Marinacci和Mukerji假设第二维的不确定性高于第一维的先验。 这在提供基础时尤其令人不安，因为先验的概念本身就是一个决定性的理论结构，就像折扣因子或阿罗-普拉特测度一样。 这个项目试图从这样的外生结构中解开理论，从对国家的直接赌注的偏好中识别代表性。 一个有趣的过程，提出了一阶preferences.In研究的最后一部分，一个实验设计来估计这种表示的参数的模糊性识别的二阶信念和聚合器，这应该产生一个完整的characterization. In。 它使用了一种新的图形选择理论设计，提供了足够的数据来自信地校准参数，而不是简单地测试假设。 这样的估计在实证应用中非常有用。这项研究的更广泛的影响是，这两种理论都特别有利于应用。 这里开发的无意识模型是按照标准主观模型的精神构建的，以便于使用。 它将标准行为和契约作为其原语。 事实上，实际合同往往是作为意外开支和付款清单来传达的。 歧义的表示允许对歧义的存在和厌恶进行单独的比较静态。 此外，这些比较静态学带有标准风险理论中的许多直觉。 通过为这种表示提供基础，可以自信地使用这些技术。 此外，这里概述的测量设备是独立的利益，因为它提供了一个通用的方法来推断模糊性规避从稀疏量的“本地”数据。 模糊性厌恶的实验校准提供了一个有用的估计，以确定其他经验模型，包括模糊性厌恶，以同样的方式，阿罗-普拉特措施的估计有助于识别经验模型，包括风险厌恶。