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.

Information order effects in clinical psychological diagnoses

“…Furthermore, Rebitschek, Bocklisch, et al () showed how stepwise diagnostic reasoning partially counteracts the primacy effect and can even lead to a recency effect (see experiments 1B, 2B, and 3). Given this procedural influence, one could speculate that stepwise diagnostic reasoning may also counteract decoy effects.…”

“…This hypothesis has also to be rejected. However, studies in diagnostic reasoning indicate that—depending on the presentation rate—both a primacy effect and a recency effect occur when the order of symptom presentation is varied (Lange, Thomas, Buttaccio, Illingworth, & Davelaar, ; Lange, Thomas, & Davelaar, ; Rebitschek, Bocklisch, et al, ). Nevertheless, there is also evidence for a recency effect in medical decision‐making (Bergus, Chapman, Levy, Ely, & Oppliger, ; Croskerry, ; Lawson & Daniel, ), consistent with our findings.…”

The Role of Physicians’ First Impressions in the Diagnosis of Possible Cancers without Alarm Symptoms

“…Larrick 42 suggests considering the opposite, as a way of avoiding confirmation bias and reducing overconfidence. Rebitschek and colleagues 36 found a reduction of the primacy effect when participants assessed each symptom in relation to each competing, potential cause. Educators could consider how such strategies can be formally and systematically introduced to the medical curricula.…”

“…There is, however, substantial evidence for predecisional information distortion in the literature, 29,30 which suggests that, as a judgment, hypothesis or preference emerges, information gets distorted to support it (either bolstered or denigrated or both), 31–33 and that this happens with not only ambiguous but also diagnostic information. 34,35 In a series of experiments on diagnostic reasoning, in which students were taught the probabilistic relationships between fictitious chemicals and resulting health symptoms and were subsequently asked to identify the chemical that had caused the presenting symptoms, Rebitschek and colleagues 36 found a strong primacy effect: once an initial, leading hypothesis was established, it determined the final diagnosis, even in cases in which subsequent information was inconsistent. The authors attributed their findings to information distortion: participants changed the subjective value of the sequentially presented information to maintain coherence with their initial hypothesis, a phenomenon also supported by a number of other studies.…”

The diversity effect in diagnostic reasoning

“…1), adapted for the chemical accident paradigm (Jahn & Braatz, 2014;Meder & Mayrhofer, 2013;Mehlhorn, Taatgen, Lebiere, & Krems, 2011;Rebitschek, Bocklisch, Scholz, Krems, & Jahn, 2015). Participants were told that patients showing symptoms (effects) may have been affected by a chemical (root cause) because of an accident in a chemical plant.…”