中文摘要
观察到的受试者在风险彩票之间所作的选择难以与期望效用最大化相协调，原因有二：一是正如 Rabin（2000）所强调的，受试者在面对小额赌局时似乎过于厌恶风险，以致无法用财富边际效用递减来解释；二是受试者的反应包含随机成分。我们为这两种异常现象提出了一种统一的解释，与知觉判断领域对相关现象的解释类似：这些异常现象源于受试者依据对决策情境的不精确（且带噪声）的心理表征所作的判断。在该模型中，风险厌恶源于某种知觉偏差——但在给定决策情境的心理表征存在局限的条件下，这种偏差体现了一种最优决策规则。我们依据有关数值认知的其他证据，提出了一个描述简单彩票的带噪声心理表征的定量模型，并检验该模型解释我们在实验室实验中观察到的选择频率的能力。
Abstract
Abstract Observed choices between risky lotteries are difficult to reconcile with expected utility maximization, both because subjects appear to be too risk averse with regard to small gambles for this to be explained by diminishing marginal utility of wealth, as stressed by Rabin (2000), and because subjects’ responses involve a random element. We propose a unified explanation for both anomalies, similar to the explanation given for related phenomena in the case of perceptual judgments: they result from judgments based on imprecise (and noisy) mental representations of the decision situation. In this model, risk aversion results from a sort of perceptual bias—but one that represents an optimal decision rule, given the limitations of the mental representation of the situation. We propose a quantitative model of the noisy mental representation of simple lotteries, based on other evidence regarding numerical cognition, and test its ability to explain the choice frequencies that we observe in a laboratory experiment.