王琛_品职助教 · 2020年12月01日
亲要回答你的两个问题，需要先了解 prospect theory 的两个组成部分 value function 和 decision weights 哈
1. prospect theory
- 首先在原版书 P18，通过对比 expected utility theory，得出 prospect theory 的两个重要组成部分：value function 和 decision weights
- "Prospect theory assigns value to gains and losses (changes in wealth) rather than to final wealth, and probabilities are replaced by decision weights."
- 其次在 P24，对两个组成部分，给出了「定性」解释
1）value function 对应 how gains and losses are evaluated
2）decision weights 对应 how uncertain outcomes are weighted
- 接着在 P26，给出了「定量」公式，以及解释
1）value function：s-shaped; moreover, as its asymmetry implies, given the same variation in absolute value there is a bigger impact of losses than of gains (loss aversion）
2）the probability-weighting function：expresses the fact that people tend to overreact to small probability events but underreact to mid-sized and large probabilities.
有了上面对 prospect theory 的两个组成部分的理解，就可以回答你的问题了
2. 解析理解
- 你问的这句话，对应的就是 probability-weighting function，也是课后题第 1 题中 client 2 符合 prospect theory 的原因
- overreact to small probability events but underreact to mid-sized and large probabilities
3. loss aversion
- loss aversion 其实对应的是 prospect theory 的 value function 部分，而不是 probability-weighting function 部分
- "steeper for losses than for gains (loss aversion)" P18
- "given the same variation in absolute value there is a bigger impact of losses than of gains" P26
