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This laboratory experiment (N=120) explored the possibility that overconfidence research concerning overestimation and overplacement may be affected by the one-half heuristic, a tendency of individuals to estimate quantities with unknown distributions at half of the maximum value. The data from multiple rounds of the computerized hand game Rock–Paper–Scissors provide convincing evidence that half of the maximum is the most popular estimate and that manipulating the game’s average score can affect the direction and magnitude of estimation, averaging, and placement levels. The resulting methodological proposal is that the score participants estimate should have an expected value equal to half of the maximum so that the hypothesized effect of the heuristic is accounted for. Additionally, this study introduces confidence levels, a standardized measure of overconfidence, allowing a direct comparison of results across studies.


ESI Working Paper 24-08



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