为什么人人都爱讲阴谋论？

我认识一位投资者总喜欢将股市拟人化，就好像道指是个活生生的野兽。“感觉像不像市场把投资者聚在一起然后迎头给你一棒？”他会这么说。仿佛“市场”是在时代广场摆摊玩三张扑克专门骗游客的坏人。

听起来不合逻辑，但现在有种投资策略越发流行，叫“技术分析”。其实是占星术的分支，即读图术，据说能“解读”市场，尽管从走势图上根本看不到任何跟公司有关的信息。人们光是看曲折的走势图就能编出个故事，例如市场“动能衰竭”，或是“触底”之类。

很多投资者痴迷于这种毫无作用的技术。行为经济学专门研究心理学在财务决策方面的作用，解释了其中原因。作者纳西姆·尼古拉斯·塔勒布称之为“叙事谬误”。从随机事件中寻找规律，事情发生后将意料之外解读为“意料之中”是人类本能倾向，也是人类的需要。

叙事谬误可以解释很多金融领域常见的错误，但理解当今世界种种政治阴谋时用处不大。这就是为何人们很难相信刺杀约翰·F·肯尼迪是一个单独行动的枪手随机行为，会想象出很多阴谋理论，其实就是不想承认混乱才是宇宙的主流，秩序没那么强大。

塔勒布的《黑天鹅》一书出版于2007年，很快变成交易员案头必备书。书中认为面对经济危机之类随机极端事件，再好的计划也没用。个人也难免受到随机事件打击，尤其是一些大灾难中恰好出现在错误地方的人，或是在曾经辉煌的行业工作，例如新闻从业者因为新科技出现失去工作。

对正常行业来说随机性的影响没那么大，只会对部分公司和个人产生巨大影响，其他人感受不到。人寿保险和退休金之所以容易测算，是因为随机性的影响不大，毕竟人类寿命不会突然大幅变化。但飓风非常难测，南弗罗里达州经营财产事故保险的公司就应该时刻准备好应付大额赔付。

许多人都很难接受其实很多领域无法预测。回顾历史也能发现很多事没法解释。总体来说，新闻事件和历史进程并没有想象中容易解读。没人能准确预测2011年911事件，也没有经济学家能在1970年预测财富分配要开始倾斜，富人变得更富，中产阶级陷入停滞。变量实在太多了，而且一些重要的变量（例如新生软件行业的潜力）当时很难意识到。

不过想避免落入叙事谬误还是有可能的。如果是经济学家，就不要把上个经济周期的规律强加在未来走势上。如果在商业界，要将分散的数据汇集起来想清楚要不要继续投资，还要避免从数据中找出连贯故事的倾向。现实很混乱。投资成功也是要在未来成功，得挺过各种复杂环境，例如经济衰退，出现新竞争者或是战争。

投资者尤其要小心过于相信股市里的故事，一旦陷入错误逻辑，任何涨跌都只会印证之前的判断。证券分析可不是寻求真相，说白了就是想尽可能低价买入。但判断很可能出错，一些随机事件可能导致判断错误。

在更广阔的的世界里，如果不愿意接受现实，即所有事很容易出错，就会导致挫败感然后开始指责。还会拼命找原因。

可以看两个正面例子。第一个来自《黑天鹅》一书。塔勒布提到“国王死了，接着王后也死了。”这句话没什么特别。但只要稍微改一下：“国王死了，然后王后也伤心致死。”看！故事出来了。人们还从中找到了因果。难怪王后也死了，原来是因为伤心。

第二个例子来自迈克尔·刘易斯的新书《失败的计划》。刘易斯描写了一个以色列心理学家丹尼尔·卡尼曼和亚摩斯·特沃斯基做的实验，在行为经济学领域比较超前。为了迷惑参与测试者，他们假想出一个“琳达”，而且描述为“31岁，单身，性格直爽而且非常聪明……非常关心社会公平。”

参与者收到的问题是下面哪个选项可能性更大——（a）“琳达是个银行柜员”或（b）“琳达是个银行柜员而且很热衷女权运动。”其实女权主义柜员琳达是柜员琳达的子集，所以正确答案应该是（a）。但85%的人都选了（b）！因为人们更愿意接受琳达是个女权主义者，所以关注社会公平。这样的琳达比较符合预先假设，也就是说对琳达的判断陷入了叙事谬误。

用刘易斯的话说，卡尼曼和特沃斯基其实在问“人们如何理解随环境变化的事物。”塔勒布提供了答案，当然两位心理学家也推测到了：人们需要听故事。

人们会发现偏执狂与阴谋论逻辑出奇地相似。原本“偏执”就是由历史学家理查德·霍夫斯塔德提出用来描述政治倾向的。肯尼迪遇刺一年后，《哈珀》杂志发表了一篇题为《美国政治中的偏执类型》，作者霍夫斯塔德在文中梳理了美国阴谋论的历史。霍夫斯塔德写道，政治上偏执的人“将种种艰难困苦归咎于人为，”仿佛总在跟（至少他自己相信）什么神奇又凶狠的“邪恶超人”生死搏斗：“就是这个恶人制造危机，弄得银行挤兑，导致衰退，诱发灾难。”

虽然霍夫斯塔德写的是麦卡锡主义，但个中描述完全适用当代很多事件，辛辛那提牛顿校园枪击案后拒绝承认事实的人，盲目抵制疫苗的人，还有唐纳德·特朗普演讲中各种各样的虚构说法（质疑奥巴马出生地，还有数百万非法投票）。半个世纪前书中的描述跃然纸上：“比起现实世界，偏执狂的逻辑缜密得多。”

《波士顿环球报》最近在俄亥俄州贝尔维尤采访了一位特朗普的支持者，他正感慨周围的家庭杂货店关门。“都怪政府不好，”他说。注意他找的指责对象，其实很有逻辑：一个简单的解释就能应付极为复杂的问题。

霍夫斯塔德描述的“逻辑连贯”其实就是叙事谬误，主要用来排解政治上的焦虑。行为经济学家已经解释为何人类这么想的根源。其实不只涉及经济学，跟政治和日常生活都有关系。讲故事让人相信和满足，符合人类的需求。王后伤心至死。呵呵，说得好像亲眼见到一样。（财富中文网）

作者：Roger Lowenstein

译者：Pessy

审稿：夏林

本文另一版本发表于2017年3月15日出版的《财富》杂志上，标题为《那些我们信以为真的故事》

I know an investor who anthropomorphizes the stock market, as if the Dow were a living beast. “Wouldn’t it be just like the market to draw us in with a rally, then deliver a sucker punch?” he will say, as if “the market” were a canny three-card monte player, entrapping tourists in Times Square.

Irrational as that may sound, it’s no more so than the ever-popular investing method known as “technical analysis.” This is a branch of astrology—¬chart -interpretation—that purportedly “reads” the market, even though it tells you nothing about the under¬ lying companies. You see a chart of zigs and zags and impute to it a story—the market is “exhausted,” or “bottoming,” or whatever.

Many investors are addicted to such fruitless techniques. Behavioral economics, which studies the impact of psychology on financial decision-making, explains why. It reflects what author Nassim Nicholas Taleb called the “narrative fallacy.” It’s the human tendency, actually the human need, to impose order on random events and to make events we didn’t anticipate seem “predictable” after the fact.

The narrative fallacy explains many common financial errors. The news is that it’s equally useful for understanding today’s conspiracy politics. It’s why, rather than accept that John F. Kennedy was killed by a lone, random gunman, we invented conspiracy theories—to spare us the ontological despair of acknowledging that chaos, not order, rules the universe.

Taleb’s The Black Swan, published in 2007, became a handbook for market traders—a reminder that random, extreme events like economic crashes overtake the best of plans. They also overtake individuals—those who happened to be in the wrong place during a natural disaster or who worked in a once-healthy industry, such as journalism, that was undercut by a new technology.

Randomness has a subtler significance for ordinary business. It delivers extreme results for some firms and human endeavors but not for others. Life insurance and pensions are predictable businesses because the randomness is contained—average life spans aren’t going to suddenly change by much. But given the unpredictability of hurricanes, a property and casualty insurer concentrated in South Florida should prepare for the possibility of very big variations in claims.

People have a tough time accepting that many realms are beyond the power to forecast. Even retrospectively, many occurrences cannot be explained. In general, news events and historical developments are less predictable than people suppose. No one could have forecast Sept. 11, 2001, with any useful specificity—nor could economists foresee in 1970 that wealth distribution was about to skew, the rich were about to get richer, and middle America was going to stagnate. The number of variables is simply too great. The important variables (say, the potential of a new industry called software) might not even be recognized.

It’s possible to avoid falling for the narrative fallacy. If you’re an economist, this means trying not to superimpose, say, a pattern from the last economic cycle on the future. If you’re in business, assessing diffuse data to figure out whether to go ahead with an investment, it means resisting the temptation to see a coherent story in that data. Reality is messy. If the investment works, it will have to work in a future that abides a wide range of ¬environments—recessions, new competitors, wars.

Investors, in particular, should be wary of falling in love with a stock’s story, after which every data point is seen as confirmation. Securities analysis is not an exercise in metaphysical truth seeking. It’s a prosaic business of buying stocks at a discount. But judgments can be wrong, or random stuff can make them wrong.

In the broader world, refusing to accept that stuff can go randomly wrong can lead to frustration, then to blame. A reason is sought.

Consider a pair of benign examples. The first is from The Black Swan. Taleb offers the sentence “The king died, and the queen died.” It is unmemorable. Then a slight refinement: “The king died, and then the queen died of grief.” Voilà! We have narrative; what’s more, we have the satisfaction of causation. No need to wonder why the queen died—it was from grief.

The second is from Michael Lewis’s new book, The Undoing Project. Lewis describes an experiment conducted by the Israeli psychologists Daniel Kahneman and Amos Tversky, pioneers in behavioral economics. For the purpose of quizzing unknowing test subjects, the two invented ¬“Linda.” They cast her as a type: “31 years old, single, outspoken and very bright … deeply concerned with issues of social justice.”

They then asked subjects which was more likely—(a) “Linda is a bank teller” or (b) “Linda is a bank teller and is active in the feminist movement.” Since feminist bank-teller Lindas are a subset of all bank-teller Lindas, the correct answer is (a). But 85% of the subjects said (b)! People find it easier to engage with a feminist Linda who cares about social justice. This Linda adheres to a preconceived type; she bows to the narrative fallacy.

Kahneman and Tversky, in Lewis’s words, were asking how “a person’s understanding of what he sees change(s) with the context in which he sees it.” Taleb supplies an answer, also anticipated by the psychologists: People need narrative.

It’s striking how similar this is to the language of paranoia and conspiracy. The idea of “paranoia” as a political tendency was introduced by historian Richard Hofstadter. In “The Paranoid Style in American Politics,” an essay that appeared in Harper’s Magazine a year after the Kennedy assassination, Hofstadter traced the history of conspiracy theory in American life. A politically paranoid person, Hofstadter wrote, “is always manning the barricades of civilization,” engaged (so he believes) in a life-and-death struggle against an “amoral superman” endowed with magical, malevolent powers: “He makes crises, starts runs on banks, causes depressions, manufactures disasters.”

Although Hofstadter was writing about McCarthyism, his words apply equally to contemporary Newtown school-shooting deniers, vaccine paranoids, and the sundry confabulations (birtherism, millions of illegal voters) echoed in Donald Trump’s speeches. From the distance of half a century, one phrase leaps off the page: “The paranoid mind is far more coherent than the real world.”

The Boston Globe recently talked to a supporter of the President in Bellevue, Ohio, who lamented the disappearance of mom-and-pop stores. “You can thank the government for that,” he said. Notice how his chosen culprit supplies coherence: a simple explanation for a numbingly complex issue.

Hofstadter’s “coherence” is the narrative fallacy, harnessed to the saddle of political anxiety. Behavioral economists have shown us why we’re prone to think that way. Their insights go far beyond economics, to politics and ordinary life. Narrative fulfills and satisfies. It answers a human need. The queen died of grief. If only we knew it.

A version of this article appears in the March 15, 2017 issue of Fortune with the headline "The Stories We Fall For."