Does uncertainty about an outcome influence decisions? The sure-thing principle (Savage, 1954) posits that it should not, but Tversky and Shafir (1992) found that people regularly violate it in hypothetical gambling and vacation decisions, a phenomenon they termed “disjunction effect”. Very close replications and extensions of Tversky and Shafir (1992) were conducted in this paper (N = 890, MTurk). The target article demonstrated the effect using two paradigms in a between-subject design: here, an extension also testing a within-subject design, with design being randomly assigned was added. These results were consistent with the original findings for the “paying to know“ problem (original: Cramer’s V = 0.22, 95% (CI) [0.14, 0.32]; replication: Cramer’s V = 0.30, 95% CI [0.24, 0.37]), yet not for the “choice under risk” problem (original: Cramer’s V = 0.26, 95% CI [0.14, 0.39]; replication: Cramer’s V = 0.11, 95% CI [−0.07, 0.20]). The within-subject extension showed very similar results. Implications for the disjunction effect and judgment and decision-making theory are discussed, and a call for improvements on the statistical understanding of comparisons of between-subject and within-subject designs is introduced. All materials, data, and code are available on https://osf.io/gu58m/.

结果不确定性会影响决策吗？确定性原则（Savage，1954）提出不应这样做，但是Tversky和Shafir（1992）发现人们经常在假设的赌博和度假决定中违反该原则，这种现象被称为“分离效应”。Tversky和Shafir（1992）进行了非常接近的复制和扩展（N = 890，MTurk）。目标文章使用主题间设计中的两个范式演示了这种效果：这里，还扩展了一个测试主题内设计的扩展，并随机分配了设计。这些结果与“付钱知道”问题的原始发现相符（原始：Cramer's V = 0.22，95％（CI）[0.14，0.32]；重复：Cramer's V = 0.30，95％CI [0.24，0.37] ），但不适用于“面临风险的选择”问题（原始数据：Cramer的V = 0.26，95％CI [0.14，0.39]；复制：Cramer的V = 0.11，95％CI [−0.07，0.20]）。受试者内部的扩展显示出非常相似的结果。讨论了析取效应，判断和决策理论的含义，并呼吁改进对主体间和主体间设计比较的统计理解。