title: Biased Processing of Ambiguous Symptoms Favors the Initially Leading Hypothesis in Sequential Diagnostic Reasoning.
abstract: In sequential diagnostic reasoning, observed pieces of evidence activate hypotheses in memory and are integrated to reach a final diagnosis. The order of evidence can influence diagnostic reasoning. This article examines the processing of ambiguous evidence underlying order effects if multiple hypotheses are activated. In five experiments with a quasi-medical scenario, participants dealt with symptom sequences supporting multiple diagnoses. The symptom order, the response mode (end-of-sequence, step-by-step), and the consistency of evidence were manipulated. A primacy order effect occurred with both response modes suggesting that ambiguous pieces of evidence were distorted toward the hypothesis that strongly corresponded with the first piece. The primacy effect was partially counteracted by stepwise belief ratings, which strengthened the weight of recent evidence and promoted switching to an alternative diagnosis. We conclude that once hypotheses are generated, the interplay of coherence-oriented information distortion and memory-dependent analytic processes propagates into distinct order effects in diagnoses.
authors.affiliation: 1 Department of Psychology, University of Greifswald, Germany.
authors.forename: Felix G
authors.initials: FG
authors.lastname: Rebitschek
authors.affiliation: 2 Department of Psychology, Technische Universität Chemnitz, Germany.
authors.forename: Franziska
authors.initials: F
authors.lastname: Bocklisch
authors.affiliation: 2 Department of Psychology, Technische Universität Chemnitz, Germany.
authors.forename: Agnes
authors.initials: A
authors.lastname: Scholz
authors.affiliation: 2 Department of Psychology, Technische Universität Chemnitz, Germany.
authors.forename: Josef F
authors.initials: JF
authors.lastname: Krems
authors.affiliation: 1 Department of Psychology, University of Greifswald, Germany.
authors.forename: Georg
authors.initials: G
authors.lastname: Jahn
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D008297:Male; D008568:Memory / Q000502:physiology*; D009483:Neuropsychological Tests; D013850:Thinking / Q000502:physiology*; D055815:Young Adult
keywords: belief updating; diagnostic reasoning; evidence integration; information distortion; order effects; probabilistic inference