Price P C, Yates J F
Department of Psychology, University of Michigan, Ann Arbor 48104-2994.
Mem Cognit. 1993 Sep;21(5):561-72. doi: 10.3758/bf03197189.
We investigated a phenomenon called judgmental overshadowing. Subjects predicted whether each of several patients had a disease on the basis of whether or not the patient had each of two symptoms. For all the subjects, the presence of the disease was moderately contingent on the presence of one of the symptoms (S1). In Condition 1 of our first experiment, the presence of the disease was highly contingent on the presence of the other symptom (S2). In Condition 2, the presence of the disease was independent of S2. Judgmental overshadowing occurred in that the S1-disease contingency was judged to be stronger in Condition 2 than in Condition 1. Subsequent experiments showed that judgmental overshadowing depends little on the form of the judgment, is not due to a response bias or contrast effect, and does not depend on subjects' actively diagnosing each patient. These results are consistent with, and are generally predicted by, an associative-learning model of contingency judgment.
我们研究了一种被称为判断性遮蔽的现象。受试者根据几位患者是否有两种症状中的每一种来预测每位患者是否患有某种疾病。对所有受试者而言，疾病的存在与其中一种症状（S1）的存在有中等程度的相关性。在我们第一个实验的条件1中，疾病的存在与另一种症状（S2）的存在高度相关。在条件2中，疾病的存在与S2无关。出现了判断性遮蔽，即S1与疾病的相关性在条件2中被判断为比在条件1中更强。后续实验表明，判断性遮蔽几乎不依赖于判断形式，不是由反应偏差或对比效应导致的，也不依赖于受试者对每位患者进行主动诊断。这些结果与偶然性判断的联想学习模型一致，并且通常由该模型预测得出。
