Forgetting can be a salient source of uncertainty for subjective beliefs, confidence, and ambiguity attitudes. To investigate this, we run several experiments where people bet on propositions (facts) that they cannot recall with certainty. We use betting preferences to infer subjects’ revealed beliefs and their revealed confidence in these beliefs. Forgetting is induced via interference tasks and time delays (up to one year). We observe a natural memory decay pattern where beliefs become less accurate and confidence is reduced as well. Moreover, we find a form of comparative ignorance where subjects are more ambiguity averse when they cannot recall the truth rather than never having learnt it. In a different vein, we identify an overconfidence pattern: on average, subjects overpay for bets on propositions that they believe in, but underpay for the opposite bets. We formulate a two-signal behavioral model of forgetting that generates all of these patterns. It suggests new testable hypotheses that are confirmed by our data.

中文翻译：

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遗忘事实时的主观信念和信心

忘记可能是主观信念，信心和模棱两可态度的不确定性的重要来源。为了对此进行调查，我们进行了一些实验，人们押注他们无法确定地回忆的命题（事实）。我们使用投注的喜好来推断受试者透露信仰及其透露的信心在这些信念。忘记是通过干扰任务和时间延迟（长达一年）引起的。我们观察到一种自然的记忆衰退模式，其中信念变得不那么准确，信心也降低了。此外，我们发现了一种比较无知的形式，即当受试者无法回忆起真理而不是从未学习过真理时，他们就会变得更加模棱两可。换句话说，我们确定了过度自信模式：平均而言，受试者为他们所相信的命题多付赌注，但为相反的赌注少付钱。我们制定了遗忘的两信号行为模型，该模型生成了所有这些模式。这表明我们的数据证实了新的可检验的假设。