The Longshot Bias Is a Context Effect
研究发现赌徒高估高风险赌注的“长线偏差”源于对比效应：赌注的收益维度比概率维度更易比较，从而增强了长线赌注的吸引力。历史赔率分析和实验室实验支持这一解释，且当赌注单独呈现或概率易比较时偏差消失。
In nearly every betting market, gamblers overvalue the riskiest bets. This “longshot bias” is usually explained by a tendency to overweight low-probability events. We offer a novel explanation: contrast effects enhance the attractiveness of longshots because gambles presented in terms of their payoffs are easier to compare along the payoff dimension than along the probability dimension. Our analysis of historical betting odds suggests that contrasts between gamble payoffs can explain the longshot bias. Laboratory experiments confirm those contrast effects and show that the longshot bias disappears when gamblers consider bets in isolation or when winning probabilities are easier to compare. This paper was accepted by Manel Baucells, behavioral economics and decision analysis. Funding: The authors thank the University of Chicago’s Center for Decision Research and Richard Thaler for funding. Supplemental Material: The online supplement and data are available at https://doi.org/10.1287/mnsc.2023.4684 .