Wide of the mark: Evidence on the underlying causes of overprecision in judgment

• Published in: Organizational behavior and human decision processes Vol. 131; pp. 110 - 120
• Main Authors: Moore, Don A., Carter, Ashli B., Yang, Heather H.J.
• Format: Journal Article
• Language: English
• Published: New York Elsevier Inc 01.11.2015; Elsevier Science Publishing Company, Inc
• Subjects: Behavioral sciences; Belief & doubt; Causality; Confidence; Confidence intervals; Epistemic uncertainty; Judgement; Judgment; Overconfidence; Overprecision; Probability; Probability distribution; Studies; Probability; Epistemic uncertainty; Overprecision; Overconfidence; Judgment
• ISSN: 0749-5978; 1095-9920
• DOI: 10.1016/j.obhdp.2015.09.003

The reported probabilities form, on average, too flat a distribution, relative to the actual probability distribution. These data contradict the widely held assumption that overprecision in judgment arises due to overly narrow subjective probability distributions. (Experiment 3, “Still photo” quincunx condition.) [Display omitted] •We test the assumption that overprecision is due to narrow subjective probability distributions.•Subjective probability distributions are, in fact, too wide.•Findings contradict prevailing consensus on causes of overprecision.•Underprecision is reduced by experience.•Underprecision is reduced by framing the uncertainty as epistemic (vs. aleatory). Overprecision is the most robust and least understood form of overconfidence. In an attempt to elucidate the underlying causes of overprecision in judgment, the present paper offers a new approach – examining people’s beliefs about the likelihood of chance events drawn from known probability distributions. This approach allows us to test the assumption that low hit rates inside subjective confidence intervals arise because those confidence intervals are drawn too narrowly. In fact, subjective probability distributions are systematically too wide, or insufficiently precise. This result raises profound questions for the study of overconfidence.