Steven Sloman | PubMed Health

PubMed2004

Typical versus atypical unpacking and superadditive probability judgment.

Probability judgments for packed descriptions of events (e.g., the probability that a businessman does business with a European country) are compared with judgments for unpacked descriptions of the same events (e.g., the probability that a businessman does business with England, France, or some other European country). The prediction that unpacking can decrease probability judgments, derived from the hypothesis that category descriptions are interpreted narrowly in terms of typical instances, is contrasted to the prediction of support theory that unpacking will generally increase judged probabilities (A. Tversky & D. J. Koehler, 1994). The authors varied the typicality of unpacked instances and found no effect of unpacking with typical instances (additivity) and a negative effect with atypical instances (superadditivity). Support theory cannot account for these findings in its current formulation.

Humans↗

PubMed2004

The advantage of timely intervention.

Can people learn causal structure more effectively through intervention rather than observation? Four studies used a trial-based learning paradigm in which participants obtained probabilistic data about a causal chain through either observation or intervention and then selected the causal model most likely to have generated the data. Experiment 1 demonstrated that interveners made more correct model choices than did observers, and Experiments 2 and 3 ruled out explanations for this advantage in terms of informational differences between the 2 conditions. Experiment 4 tested the hypothesis that the advantage was driven by a temporal signal; interveners may exploit the cue that their interventions are the most likely causes of any subsequent changes. Results supported this temporal cue hypothesis.

Cues↗

PubMed2002

Physicians' judgments of survival after medical management and mortality risk reduction due to revascularization procedures for patients with coronary artery disease.

STUDY OBJECTIVE: s: To assess the accuracy of physicians' judgments of survival probability for medically managed patients with coronary artery disease (CAD), and of the absolute risk reduction of mortality due to coronary artery bypass grafting (CABG) or percutaneous transluminal coronary angioplasty (PTCA) for such patients; and relationships among these judgments and the physicians' propensity to perform revascularization. DESIGN: Two surveys (for three-vessel or two-vessel CAD) for patients presenting with stable CAD, currently managed medically, and without other life-limiting problems. SETTING: Multiple educational conferences, 1996-1997. PARTICIPANTS: Conference attendees. MEASUREMENTS AND RESULTS: Main outcomes were proportions of patients for whom the physicians would recommend revascularization (CABG for three-vessel CAD, CABG or PTCA for two-vessel CAD), and judgments of the proportions of medically managed patients who would be alive after 5 years, 7 years, and 11 years, and of absolute risk reduction of mortality due to CABG (or PTCA for two-vessel CAD). At least one half of the participants judged the survival rate of medically managed patients with three-vessel or two-vessel CAD to be less than the lowest rates supported by the best available evidence. More than one fourth judged the absolute risk reduction due to CABG to be higher than the highest values based on such evidence. Physicians' propensity to perform revascularization correlated inversely with their judgments of survival given medical management, and with their judgments of absolute risk reduction due to revascularization. CONCLUSIONS: Physicians may overuse revascularization because of excessive pessimism about survival of medically managed patients, and excessive optimism about the survival benefits of revascularization.

Angioplasty, Balloon, Coronary↗