Decision makers often reject mixed gambles offering equal probabilities of a larger gain and a smaller loss. This important phenomenon, referred to as loss aversion, is typically explained by prospect theory, which proposes that decision makers give losses higher utility weights than gains. In this paper we consider alternative psychological mechanisms capable of explaining loss aversion, such as a fixed utility bias favoring rejection, as well as a bias favoring rejection prior to gamble valuation. We use a drift diffusion model of decision making to conceptually distinguish, formally define, and empirically measure these mechanisms. In two preregistered experiments, we show that the pre-valuation bias provides a very large contribution to model fits, predicts key response time patterns, reflects prior expectations regarding gamble desirability, and can be manipulated independently of the valuation process. Our results indicate that loss aversion is the result of multiple different psychological mechanisms, and that the pre-valuation bias is a fundamental determinant of this well-known behavioral tendency. These results have important implications for how we model behavior in risky choice tasks, and how we interpret its relationship with various psychological, clinical, and neurobiological variables.

中文翻译：

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损失厌恶的心理机制：漂移扩散分解

决策者经常拒绝提供更大收益和更小损失的相同概率的混合赌博。这种被称为损失厌恶的重要现象通常由前景理论解释，该理论认为决策者给予损失的效用权重高于收益。在本文中，我们考虑了能够解释损失厌恶的替代心理机制，例如有利于拒绝的固定效用偏差，以及在赌博估值之前有利于拒绝的偏差。我们使用决策的漂移扩散模型来概念区分、形式定义和经验测量这些机制。在两个预先注册的实验中，我们表明预估值偏差对模型拟合提供了非常大的贡献，预测了关键响应时间模式，反映了对赌博可取性的先前期望，并且可以独立于估值过程进行操作。我们的研究结果表明，损失厌恶是多种不同心理机制的结果，预估偏差是这种众所周知的行为倾向的基本决定因素。这些结果对我们如何模拟风险选择任务中的行为，以及我们如何解释其与各种心理、临床和神经生物学变量的关系具有重要意义。