Vanderbilt Law School, Nashville, TN, USA.
Kennedy School of Government, Harvard University, Cambridge, MA, USA.
Risk Anal. 2017 May;37(5):969-981. doi: 10.1111/risa.12701. Epub 2017 Jan 17.
Recollection bias is the phenomenon whereby people who observe a highly unexpected event hold current risk beliefs about a similar event that are no higher than their recollection of their prior beliefs. This article replicates and extends the authors' previous study of recollection bias in relation to individuals' perceptions of the risks of terrorism attacks. Over 60% of respondents in a national U.S. sample of over 900 adults believe that the current risk of a future terrorist attack by either an airplane or in a public setting is no higher than they recall having believed, respectively, before the 9/11 attack and before the Boston Marathon bombing. By contrast, a rational Bayesian model would update to a higher currently assessed risk of these previously uncontemplated events. Recollection bias is a persistent trait: individuals who exhibited this bias for the 9/11 attack exhibited it for the Boston Marathon bombing. Only one-fifth of respondents are free of any type of recollection bias. Recollection bias is negatively correlated with absolute levels of risk belief. Recollection bias in relation to highly unexpected terrorist events-the belief that perceived risks did not increase after the surprise occurrence-dampens support for a variety of anti-terrorism measures, controlling for the level of risk beliefs and demographic factors. Persistent recollection bias for both 9/11 and the Boston Marathon bombing is especially influential in diminishing support for protective policy measures, such as surveillance cameras in public places. Given that public attitudes influence policy, educating the public about risk is critical.
记忆偏差是指人们观察到一个高度意外的事件时，当前对类似事件的风险信念不会高于他们对先前信念的记忆。本文复制并扩展了作者之前关于记忆偏差与个人对恐怖袭击风险感知的研究。在美国一项针对 900 多名成年人的全国性抽样调查中，超过 60%的受访者认为，未来发生的飞机恐怖袭击或公共场所恐怖袭击的当前风险与 9·11 袭击前和波士顿马拉松爆炸案前相比，他们的记忆中分别认为的风险要低。相比之下，一个理性的贝叶斯模型会更新这些之前未曾考虑过的事件的当前风险评估。记忆偏差是一种持续存在的特征：对 9·11 袭击表现出这种偏差的人，对波士顿马拉松爆炸案也表现出了这种偏差。只有五分之一的受访者没有任何类型的记忆偏差。记忆偏差与绝对风险信念水平呈负相关。对高度意外的恐怖事件的记忆偏差——即认为在意外发生后感知到的风险没有增加——削弱了对各种反恐措施的支持，控制了风险信念水平和人口统计因素。对 9·11 事件和波士顿马拉松爆炸案的持续记忆偏差，对降低对保护政策措施的支持，如公共场所的监控摄像头，尤其有影响。鉴于公众态度会影响政策，对公众进行风险教育至关重要。
