# Descriptive Decision Theory

> 【EN】Descriptive decision theory is concerned with characterising and explaining regularities in the choices that people are disposed to make. It is standardly distinguished from a parallel enterprise, normative decision theory, which seeks to provide an account of the choices that people ought to be disposed to make. Much of the work in this area has been devoted to the building and testing of formal models that aim to improve on the descriptive adequacy of a framework known as “Subjective Expected Utility” (SEU). This adequacy was first called into question in the middle of the last century and further challenged by a slew of experimental work in psychology and economics from the mid 1960s onwards. … 【中】描述性决策理论关注刻画与解释人们实际倾向于做出的选择中的规律性，通常与并行的规范决策理论相区别——后者旨在说明人们应当倾向于做出怎样的选择。该领域大量工作用于建立并检验改进主观期望效用（SEU）描述充分性的模型。词条讨论萨维奇的证明、概率三角、独立性问题（含阿莱悖论）、概率精致化、非可加的概率与多先验等理论回应。

- ID: m13186
- Category: decide
- Domain: 决策科学

## Definition

描述性决策理论旨在刻画与解释人们实际倾向于做出的选择中的规律性；它与规范决策理论相对，后者试图说明人们应当倾向于做出怎样的选择。该领域大量工作用于建立并检验改进主观期望效用框架描述充分性的形式模型。 脚手架作用：- 偏差识别：对照规范模型找出实际选择的系统性偏离。 - 行为预判：依实测规律推测他人在风险下会怎么选。 - 误差归因：区分能力不足与偏好不同，判断是否真非理性。

## How it works

SEU 把选择解释为在主观概率与效用下的期望最大化，但实验显示实际选择会系统性偏离其公理：阿莱悖论暴露独立性公理的失效，含混规避显示人们并不按单一概率行动。于是理论家或把概率放宽为非可加容量，或改用多先验集合上的最坏情形排序，以提高预测力。

## Practice

1) 先明确任务是预测实际选择还是评估应当如何选择，二者不可混用。2) 用阿莱式、含混式的成对选择检验独立性等公理是否成立。3) 若系统性违反，改用非期望效用模型。4) 用新样本检验模型的预测力。

## Use

- 偏差识别：对照规范模型找出实际选择的系统性偏离。 - 行为预判：依实测规律推测他人在风险下会怎么选。 - 误差归因：区分能力不足与偏好不同，判断是否真非理性。

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