Do People Inherently Dislike Uncertain Advice?

The authors present a reconciliation of 3 distinct ways in which the research literature has defined overconfidence: (a) overestimation of one's actual performance, (b) overplacement of one's performance relative to others, and (c) excessive precision in one's beliefs. Experimental evidence shows that reversals of the first 2 (apparent underconfidence), when they occur, tend to be on different types of tasks. On difficult tasks, people overestimate their actual performances but also mistakenly believe that they are worse than others; on easy tasks, people underestimate their actual performances but mistakenly believe they are better than others. The authors offer a straightforward theory that can explain these inconsistencies. Overprecision appears to be more persistent than either of the other 2 types of overconfidence, but its presence reduces the magnitude of both overestimation and overplacement.

In explaining the prevalence of the overconfident belief that one is better than others, prior work has focused on the motive to maintain high self-esteem, abetted by biases in attention, memory, and cognition. An additional possibility is that overconfidence enhances the person's social status. We tested this status-enhancing account of overconfidence in 6 studies. Studies 1-3 found that overconfidence leads to higher social status in both short- and longer-term groups, using naturalistic and experimental designs. Study 4 applied a Brunswikian lens analysis (Brunswik, 1956) and found that overconfidence leads to a behavioral signature that makes the individual appear competent to others. Studies 5 and 6 measured and experimentally manipulated the desire for status and found that the status motive promotes overconfidence. Together, these studies suggest that people might so often believe they are better than others because it helps them achieve higher social status.

Judges were asked to make numerical estimates (e.g., "In what year was the first flight of a hot air balloon?"). Judges provided high and low estimates such that they were X% sure that the correct answer lay between them. They exhibited substantial overconfidence: The correct answer fell inside their intervals much less than X% of the time. This contrasts with choices between 2 possible answers to a question, which showed much less overconfidence. The authors show that overconfidence in interval estimates can result from variability in setting interval widths. However, the main cause is that subjective intervals are systematically too narrow given the accuracy of one's information-sometimes only 40% as large as necessary to be well calibrated. The degree of overconfidence varies greatly depending on how intervals are elicited. There are also substantial differences among domains and between male and female judges. The authors discuss the possible psychological mechanisms underlying this pattern of findings.