On Risk and Rationality
On Risk and Rationality
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论风险与理性
DOI：
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发表时间：
2014
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通讯作者：
B. Armendt
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作者：
B. Armendt
人们普遍认为，风险对理性决策的影响不能完全用代理人效用曲线的形状来解释。Buchak （Erkenntnis, 2013, Risk and rationality, Oxford University Press, Oxford, in Press）提出了一种公理决策理论——风险加权期望效用理论（REU），其中决策权重是由其风险函数r修正的主体主观概率。对REU进行了简要描述，并讨论了r的全局适用性。Rabin （Econometrica 68:1281-1292, 2000）的校准定理强烈表明，风险厌恶的合理水平不能完全用凹效用函数来解释；这为REU和其他理论提供了动力。但将其应用于个体行为者的共时性偏好，拉宾的结果并不像乍看起来那样有问题。将结果视为收益和损失的理论（例如前景理论和累积前景理论）以REU无法获得的方式解释风险敏感性。标记收益和损失之间差异的参考点受制于框架，其中许多情况不能被视为合理的。然而，理性决策理论可能会认识到收益和损失之间的差异，而不是赞同所有固定参考点的方法。无论如何，REU是一个非常有趣的理论。
It is widely held that the influence of risk on rational decisions is not entirely explained by the shape of an agent’s utility curve. Buchak (Erkenntnis, 2013, Risk and rationality, Oxford University Press, Oxford, in press) presents an axiomatic decision theory, risk-weighted expected utility theory (REU), in which decision weights are the agent’s subjective probabilities modified by his risk-function r. REU is briefly described, and the global applicability of r is discussed. Rabin’s (Econometrica 68:1281–1292, 2000) calibration theorem strongly suggests that plausible levels of risk aversion cannot be fully explained by concave utility functions; this provides motivation for REU and other theories. But applied to the synchronic preferences of an individual agent, Rabin’s result is not as problematic as it may first appear. Theories that treat outcomes as gains and losses (e.g. prospect theory and cumulative prospect theory) account for risk sensitivity in a way not available to REU. Reference points that mark the difference between gains and losses are subject to framing, many instances of which cannot be regarded as rational. However, rational decision theory may recognize the difference between gains and losses, without endorsing all ways of fixing the point of reference. In any event, REU is a very interesting theory.