Intuitive Biases in Choice versus Estimation: Implications for the Wisdom of Crowds
通过NFL博彩实验发现，群体在预测比赛时存在直觉偏差，偏好热门队而忽视让分盘的不利影响，且偏差随时间加剧；但改用估计分差的方式后，群体预测变得无偏且更明智。
Although researchers have documented many instances of crowd wisdom, it is important to know whether some kinds of judgments may lead the crowd astray, whether crowds’ judgments improve with feedback over time, and whether crowds’ judgments can be improved by changing the way judgments are elicited. We investigated these questions in a sports gambling context (predictions against point spreads) believed to elicit crowd wisdom. In a season-long experiment, fans wagered over $20,000 on NFL football predictions. Contrary to the wisdom-of-crowds hypothesis, faulty intuitions led the crowd to predict “favorites” more than “underdogs” against point spreads that disadvantaged favorites, even when bettors knew that the spreads disadvantaged favorites. Moreover, the bias increased over time, a result consistent with attributions for success and failure that rewarded intuitive choosing. However, when the crowd predicted game outcomes by estimating point differentials rather than by predicting against point spreads, its predictions were unbiased and wiser.