投资的怪圈

许多投资者的行为方式似乎表明他们在模仿哈佛大学的哲学家威拉德·范奥曼·奎因（Willard van Orman Quine）。[51]在早期的职业生涯中，奎因从打字机上拆掉了问号键。后来，在其晚年，有人问他是如何做到70年来从未打过一个问号，他回答说：“哦，你看到了，我只跟肯定的事情打交道。”但在金融市场的投资中，几乎没有什么是确定无疑的，你的大脑会夸大你的能力，偏爱熟悉的事物，并想象自己比以往任何时候都更能掌控过去和未来。因此，对我们而言，如果我们不拿掉键盘上的问号键，而是把大部分其他的键都拿掉，用问号替代它们，我们或许会感到更加舒服。

但是你不想把自己的自信削弱到零。没有信心的投资者永远不会投资，因为投资至少需要对未来的不确定因素采取某种立场。所以，你的目标是尽可能准确地判断自己知道什么及不知道什么。你知道多少并不重要，重要的是你清楚地知道自己的无知边界从哪里开始。几乎一无所知甚至都不是问题，只要你知道自己几乎一无所知就行了。你可以按照下面的方法来调整你的自信。

➢给自己一个心理暗示：我不知道，也不在乎。[52]说“我不知道”并不是什么可耻的事情。要想成为一名成功的投资者，你没必要在华尔街创造的猜谜游戏中打败华尔街。你不需要知道易贝的收益是多少，能源和黄金股是否会继续上涨，下个月的失业报告会说什么，或者利率和通货膨胀率的走向如何。全股票市场指数基金就是一个囊括低成本股票的篮子。如果你索性直接买入并长期持有其中两只基金（一只是美国市场的，另一只是非美国市场的），那么你就不再需要对哪些股票、行业或领域表现好或差形成什么看法。这样一来，虽然你直接拒绝了预测游戏，但能赢得这个游戏。

全股票市场指数基金使你有底气说出“我不知道，也不在乎”这几个神奇的字眼。如果有人问你：“下一个高速增长的行业将是互联网还是煤矿？”你完全可以底气十足地回答说：“我不知道，也不在乎，因为我的指数基金同时拥有这两类公司的股票。”如果有人问你：“小型股会比大型股表现更好吗？”你可以底气十足地回答说：“我不知道，也不在乎，因为我的指数基金同时拥有这两类公司的股票。”如果有人问你：“谁将主宰计算机的未来？微软，谷歌，还是一些未知的后起之秀？”你可以底气十足地回答说：“我不知道，也不在乎，因为我的指数基金同时拥有它们的股票。”如果有人问你：“未来几十年，世界上最好的股票市场是什么？”你可以底气十足地回答说：“我不知道，也不在乎，因为我的指数基金同时拥有它们的股票。”

➢把“太难”的问题堆到一边。[53]许多人认为，沃伦·巴菲特之所以成为世界上最成功的投资者，是因为他比任何人都懂得多。但巴菲特本人认为，他成功的关键在于“知之为知之，不知为不知”。他说：“我们对所有的事情都有诸多怀疑，但我们偏偏忘记了这些怀疑。”他补充道：“最基本的原则是像查理·芒格所说的那样，把‘太难’的问题堆到一边。也就是说，我们要把不知道如何评估的问题搁置起来，而我们99%的想法都应该归入此类。”因此，你的工作空间里应该有三个小盒子，第一个装着一些你要考虑的想法，第二个装着你已经明确同意或拒绝的想法，第三个装着实在难以评估的想法。（如果你真的非常认真地想投资，那就在废纸篓边上贴上“太难”二字，把太难决定的文件扔进去。如果你什么事情都是在电脑上做的，那就在桌面创建一个名为“太难”的文件夹。）在你考虑一个想法之前，先自问一下这个问题是否属于“太难”那一类。（如果你不确定一个问题是否“太难”，那它肯定是“太难”了！）

➢评估两次再出手。[54]如果你曾经亲眼见识过一位木匠大师的工作，那么你就会注意到他造成的废料或废木头是多么少，因为他在切割前会非常仔细地测量。所以，在首次对一只股票进行评估之后，你不妨多评估一次。行为金融学作家加里·贝尔斯基（Gary Belsky）和心理学家托马斯·基洛维奇（Thomas Gilovich）建议，为了降低“过度自信”的程度，要将其削减25%。比如，如果你评估一只股票的价值是40~60美元，然后将每个数字削减25%，形成了30~45美元的新区间。这种保守的评估会帮助你避免被自己的过分自信冲昏头脑。

➢写投资日记。[55]心理学家巴鲁克·费斯科霍夫研究“过度自信”问题已有30多年，他建议投资者写投资日记。他说：“记录下你做出预测时脑子里在想什么，并尽可能使这些预测清晰明了。”要从概率角度去考虑问题，包括价格区间和日期，比如，我认为这只股票有70%的可能性在一年内达到20~24美元。（别忘了给你的价格区间打一个25%的折扣。）最后，把你的投资想法用下列句子表述出来：“我认为这笔投资将赚钱，因为……”

在购买之前，把你投资的原因记录下来是很重要的。长期研究记忆的心理学家伊丽莎白·洛夫特斯（Elizabeth Loftus）已经证明，你对早期感觉的回忆很容易受到后来发生的事情的影响。如果你在事后记日记，你对最初动机的记忆可能会受到后来价格变化的影响。（比如，你事后可能会写“我之前以14美元的价格买入，因为我知道它会马上涨到15美元”。）

把你的日记存起来一年，然后回过头来看看你的预测有多准确，你是否倾向于低估或高估，以及你的投资理论究竟有多好。这样做并不是为了看你的投资是否增值了，因为此时此刻你已经知道了结果。相反，你需要看的是它们是否因你预期的原因而上涨了。这有助于你知道你获益是因为你的预测是对的，还是仅仅得益于好运气。反过来，这会帮助你控制住内心的骗子。此外，有了真正的“后见之明”以后，你现在就可以问自己，什么样的附加信息会帮你提高做出正确决定的可能性，或者提供更准确的价格区间。

➢通过追踪不明智的投资去总结经验和教训。[56]当我们自己的行为得到及时而明确的反馈时，我们才会从中学习得最好。这就是为什么老师们会立即批改作业，并给出具体的分数和改进建议。（想象一下，如果你永远不知道什么时候能把作业拿回来，或者得到的反馈只是“到目前为止作业写得还不错”，那么学校会是什么样子。）

不幸的是，金融市场充斥着混乱的反馈。假设你以10美元的价格买入了一只股票，很快涨到了11美元，你就会觉得自己聪明，进而自鸣得意。但你的高兴劲儿还没退，股价却跌到了9美元，你又觉得自己很愚蠢。一个决定的好坏，在一定程度上取决于你的评估时机。从短期来看，你赖以评估的证据（即真实股价）是不断变化的，股价有涨有跌，你便觉得自己的决定有对有错，有聪明也有愚蠢。要想对自己的选股能力有一个可靠的了解，你需要跟踪很长一段时间，并综合考虑多个选择，然后对其进行评估。你还需要看看自己想买而未买的股票的走势。庞培法布拉大学的心理学家罗宾·霍加斯建议你长期跟踪三类股票的表现：一类是那些你正在持有的，一类是你已经卖出的，一类是你想买但尚未买入的。要做到这一点，你可以使用组合投资网站，比如www.morningstar.com。

这种做法对专业投资者、理财规划师或任何经常交易的人特别有用。它不仅仅可以告诉你股票的涨跌，还能告诉你已经卖出的股票是否持续上涨，以及你想买却未买的股票是否比你之前买入的股票表现更好。要确定你的买卖决策究竟有多好，这三方面的信息都是必须掌握的。

➢给你内心的骗子戴上手铐。[57]你可以通过问三个问题来避免误判自己的能力：

1.我的收益水平比平均水平高多少？

2.我能达到什么样的水平？

3.随着时间的推移，其他人的平均表现如何？

比如，你认为自己在选股方面比平均水平高出25%，你认为自己的投资组合每年能赚15%。在考虑第三个问题之前，这听起来很现实。标准普尔500指数的蓝筹股的长期平均年回报率为10.4%。然而，如果你根据人们在投资组合中增加和减少的现金量来调整这个数字，那么1926年以来的年均回报率会下降到8.6%。考虑到税收成本、交易成本和通货膨胀，典型投资者的年回报率会下降到4%以下。如果你真的比平均水平高出25%，那么在扣除所有成本后，你的年回报率不大可能高于5%。你的选股水平至少要比平均水平高出3倍，才有可能每年赚15%。

➢接受错误。[58]纽约戴维斯精选顾问公司（Davis Selected Advisors）的克里斯托弗·戴维斯（Christopher Davis）管理着价值600多亿美元的基金。他用股票装饰办公室外面的墙壁，但获得这一“殊荣”的股票并不是该公司最佳的投资，反而是最差的投资。该区域被戏称为“错误墙”，展示了16家公司的股票。戴维斯挖苦地说：“刚挂上去一个，另一个就要装进相框了。一开始，我没有想到它会变成这样的壁画。”有一家公司，名叫“韦斯特管理公司”（Waste Management），其股票两次出现在“错误墙”上，因为戴维斯不仅因为错误的原因买了它，而且在错误的情况下卖掉了它。对戴维斯来说，一个错误意味着在信息错误或分析有所缺陷的基础上，对一个企业的价值做出了重大的误判，而这些误判本来是可以避免的。

当事实证明交易某只股票是一个错误时，戴维斯就会将该股票用相框装裱起来并挂到墙上，同时简要总结一下从错误中可以学到什么。许多基金经理谈论投资回报率或净资产收益率，而戴维斯也发明了一个词，名为“错误回报率”（return on mistake）。虽然戴维斯错误地卖出了挂在“错误墙”上的韦斯特管理公司的股票，但这使他阴差阳错地没有在最悲观的时刻卖掉泰科国际（Tyco International）的股票（其股价后来涨了两倍）。戴维斯从对朗讯科技的错误投资中总结出了一个教训，即“不要对自己不理解的回答感到满意”。正是这个教训阻止了戴维斯基金在安然公司破产前买入其股票。

你要从投资错误中总结教训，也没有必要专门给投错的股票弄一个相框。可以简单地把你投错的股票名字和教训写在便签纸上。直面你的错误，而不是掩盖它们，就可以把它们从负债变成资产。研究你的错误并把它们放在显眼的地方，可以帮助你避免重蹈覆辙。

➢不要只买你知道的东西。[59]富达麦哲伦基金（Fidelity Magellan Fund）富有传奇色彩的经理彼得·林奇曾以建议投资者购买熟悉的产品而闻名。林奇写道，你可以通过投资那些你亲自消费其产品和服务的公司，“让你的常识发挥用武之地”。比如，林奇投资墨西哥快餐品牌塔可钟（Taco Bell）的股票是因为他喜欢该公司的墨西哥卷饼，投资沃尔沃是因为他开过一辆该公司生产的汽车，投资唐恩都乐（Dunkin Donuts）是因为他喜欢它的咖啡，投资恒适（Hanes）是因为他的妻子喜欢它的L’eggs系列连裤袜。

然而，投资者经常忘记的是，林奇投资唐恩都乐并不仅仅是因为他喜欢它的咖啡和甜甜圈，他还花了数小时分析该公司的财务报表，研究有关该公司及其业务的一切因素。仅仅因为喜欢某家公司的产品或服务就买入它的股票，就像仅仅因为喜欢一个人的穿着就决定和其结婚一样。如果你因为熟悉一家公司销售的东西而对其感兴趣，固然是件好事，但你不应该在没有事先审视投资清单的情况下就贸然买入其股票。（关于排除某些投资的规则清单，见附录2。）

➢不要局限于自己所在公司的股票。[60]不管你对自己的公司多么熟悉，也不管你从自己的公司中得到了多少温暖，它的股票都堪称风险最高的投资之一。2004年9月30日，默克公司（Merck & Co.）宣布召回其广受欢迎的关节炎药物万络（Vioxx），因为研究表明该药会增加患心脏病的风险。默克公司的股票也因为这个消息出现了大麻烦，在短短几分钟内就暴跌了27%。由于默克公司员工的401（k）计划账户里面，高达1/4的资金都投给了该公司的股票，导致他们超过5%的退休储蓄在一天之内化为乌有。

就在两周后，纽约州总检察长艾略特·斯皮策（Eliot Spitzer）以保险欺诈为由起诉了大型保险经纪公司威达信集团（Marsh &McLennan）。该公司员工的退休计划账户中持有12亿美元的该公司股票。该公司的股票价格在4天内暴跌48%，亏掉了超过5亿美元的退休储蓄。不到1个月后，该公司解雇了3000名员工，4个月后又裁员2500人。所有这些工人都没有工作，退休基金也少了一半。

事实上，把所有的鸡蛋放在同一个篮子里非常危险，克莱蒙特·麦肯纳学院的金融学教授丽萨·梅尔布洛克（Lisa Meulbroek）估计，如果在长达10年的时间内将投资组合的50%分配给一家公司的股票，那么考虑到你的投资组合可能遭到的各种风险因素，它的最终价值可能只剩下本金的60%。即使你只把投资组合的25%分配给一家公司的股票，那么经过风险调整之后它的价值也可能只剩下本金的74%。

试着这样想一下：你今天会死吗？也许不会，但你还是应该买人寿保险。你的房子明天会被烧毁吗？也许不会，但是给房子上保险是个好主意。你的公司会沦为下一个安然公司吗？也许不会，但为你的投资组合投保以防万一绝对是个好主意。最好的保险政策是投资自己公司的股票（或期权）的资金比例不超过10%，并将剩余的资金尽可能广泛地分散。

➢多元化是最好的防御。[61]在今天看来，如果你在20世纪80年代初把所有的钱都投入计算机相关的股票，你显然可以赚一大笔钱，但后见之明偏误使你看不到真相。回到个人计算机时代的初期，你不可能想到买入微软的股票。事实上，微软直到1986年才上市。当时科技领域的超级明星是宝来公司（Burroughs）、康懋达国际（Commodore International）、计算机视觉公司（Computervision）、克雷研究公司（Cray Research）、迪吉多（Digital Equipment）、普莱莫计算机公司（Prime Computer）、坦迪公司（Tandy）和王安实验室（Wang Laboratories）。的确，在1980年12月苹果公司首次公开发行股票之后，你本可以买下苹果公司的股票，但你可能想要的是康懋达国际的股份，因为如果你早在1974年底将1万美元投给康懋达国际，到1980年12月就变成了170万美元。

计算机行业早期的明星几乎都一个接一个地黯然失色了。它们的创新产品失去了优势，最优秀的人才流失了，最终走向破产或被人们遗忘。几乎所有这些股票的投资者都一败涂地。回头来看，最初选择微软和苹果的人显然都成了赢家。但在当时的情况下，谁也不清楚哪些公司会赢得胜利，只有竞争形势明朗之后，才能看出来。

这就是为什么多元化投资如此重要。如果你在国内外拥有多样化的股票和债券，基本上可以消除少量垃圾投资毁掉未来财务状况的可能性。

➢假装你才四岁。每个家长都知道，四岁的孩子有问为什么的习惯，一遍又一遍地问，直到耗尽父母的知识储备。问自己四五遍“为什么”是测试你自己（或别人）的知识极限的好方法。如果一位理财规划师对你说“你应该把一大笔钱投入专门投资中国股票的基金，因为中国是你应该投资的地方”，那么，你就要反问一句“为什么”。如果他回答“因为中国将成为世界上增长最快的经济体”，你要再问一次“为什么”。如果他回答“因为中国将继续保持低制造成本”，你还要再问一次“为什么”。很有可能，你永远不会有机会问第五个为什么。不知道自己在说什么的人很少能连续两次回答清楚“为什么”。如果你也做不到这一点，那就说明你还没有足够的知识来做出明智的决定。聪明的投资者知道，表现得像个四岁小孩通常是个好主意。

[1] Cited in Paul A. Samuelson,“Is There Life After Nobel Coronation?,” at http://nobelprize.org/economics/articles/samuelson/index.html.

[2] Caroline E. Preston and Stanley Harris,“Psychology of Drivers in Traffic Accidents,”JAP, vol. 49, no. 4 (1965), pp. 284–88; Ola Svenson,“Are We All Less Risky and More Skillful than Our Fellow Drivers?” Acta Psychologica, vol. 47 (1981), pp.143–48.

[3] JZ first ran this little test, inspired by Richard Thaler of the University of Chicago,around 1998. The lowest ratio between“my savings” and“average savings” seems to be around 1.5; people often think they will save at least twice as much as the typical person in the room.

[4] JZ,“Did You Beat the Market?” MM, Jan. 2000, p. 56; Arnold C. Cooper et al.,“Entrepreneurs’ Perceived Chances for Success,” Journal of Business Venturing, vol.3 (1988), pp. 97–108; Daniel Kahneman, remarks at the Institute of Certified Financial Planners’ Wealth Management Symposium, New York, April 30, 1999.

[5] Kenneth L. Fisher and Meir Statman,“Bubble Expectations,” Journal of Wealth Management, fall 2002, pp. 17–22; press release, Montgomery Asset Management,Jan. 12, 1998; survey conducted by Intersearch Corp., Nov. 17–Dec. 9, 1997; Robert F.Bruner,“Does M&A Pay?” http://faculty.darden.edu/brunerb/Bruner_PDF/Does%20 M&A%20Pay.pdf; JZ email interview with Bruner, Nov. 7, 2005; Neil D. Weinstein,Unrealistic Optimism about Future Life Events, JPSP, vol. 39, no. 5 (1980), pp.806–20 (this experiment was conducted with 120 students at Rutgers’s Cook College,all of them women); Barna Research Group nationwide telephone survey of more than 1,000 adult Americans, released Oct. 21, 2003, www.barna.org.

[6] Justin Kruger and David Dunning,“Unskilled and Unaware of It,” JPSP, vol. 77, no.6 (1999), pp. 1121–34; Shelley E. Taylor and Jonathon D. Brown,“Illusion and Well Being,” PB, vol. 103, no. 2 (1988), pp. 193–210. The term“con man,” of course, is short for“confidence man,” someone who earns trust by projecting a suave sense of ability, power, and knowledge (see David W. Maurer, The Big Con [New York: Anchor, 1999].)

[7] JZ,“Did You Beat the Market?” MM, Jan. 2000, pp. 55–57; Don A. Moore et al.,“Positive Illusions and Forecasting Errors in Mutual Fund Investment Decisions,”OBHDP, vol. 79, no. 2 (Aug. 1999), pp. 95–114; JZ telephone interviews with Max Bazerman and Don A. Moore, Nov. 16, 1999.

[8] JZ spoke at the Boston Globe Personal Finance Conference, Mar. 23, 2002; Bethany McLean and Peter Elkind, The Smartest Guys in the Room (New York: Portfolio,2003), pp. 242, 314, 401.

[9] Gur Huberman,“Familiarity Breeds Investment,” RFS, vol. 14, no. 3 (Fall 2001),pp. 659–80; Joshua D. Coval and Tobias J. Moskowitz,“Home Bias at Home,”JF, vol. 54, no. 6 (Dec. 1999), pp. 2045–73; Kalok Chan et al.,“What Determines the Domestic Bias and Foreign Bias?,” JF, vol. 60, no. 3 (June 2005), pp. 1495–1534; Kenneth R. French and James M. Poterba,“Investor Diversification and International Equity Markets” (Jan. 1991), www.nber.org/papers/w3609; Yesim Tokat,“International Equity Investing: Long-Term Expectations and Short-Term Departures,” Vanguard Investment Counseling & Research, May 2004, p. 11; Morgan Stanley Capital International Blue Book, Dec. 2005, p. 4; Michael Kilka and Martin Weber,“Home Bias in International Stock Return Expectations,” JBF, vol. 1, no. 3–4(2000), pp. 176–92; Shlomo Benartzi,“Excessive Extrapolation and the Allocation of 401(k) Accounts to Company Stock,” JF, vol. 56, no. 5 (Oct. 2001), pp. 1747–64.

[10] I am indebted to Professor Zeev Mankowitz of Hebrew University for this metaphor.

[11] R. B. Zajonc,“Attitudinal Effects of Mere Exposure,” JPSP, Monograph Supplement, vol. 9 (1968), pp. 1–27; JZ telephone interview with Robert Zajonc, Oct.12, 2005; William Raft Kunst-Wilson and R. Zajonc,“Affective Discrimination of Stimuli That Cannot Be Recognized,” Science, vol. 207 (Feb. 1, 1980), pp. 557–58;Jennifer L. Monahan et al.,“Subliminal Mere Exposure: Specific, General, and Diffuse Effects,”PS, vol. 11, no. 6 (Nov. 2000), pp. 462–66; R. B. Zajonc,“Mere Exposure: A Gateway to the Subliminal,” CDPS, vol. 10, no. 6 (Dec. 2001), pp. 228.Although the duration of a“blink of an eye” is highly variable, it averages roughly one-third of a second (Frans Vander Werf et al.,“Eyelid Movements: Behavioral Studies of Blinking in Humans under Different Stimulus Conditions,” Journal of Neurophysiology, vol. 89 (2003), pp. 2784–96).

[12] Rebecca Elliott and Raymond J. Dolan,“Neural Response During Preference and Memory Judgments for Subliminally Presented Stimuli: A Functional Neuroimaging Study,” JN, vol. 18, no. 12 (June 15, 1998), pp. 4697–4704; Samuel M. McClure et al.,“Neural Correlates of Behavioral Preference for Culturally Familiar Drinks,”Neuron, vol. 44 (Oct. 14, 2004), pp. 379–87.

[13] The theory of place cells was first proposed in John O’Keefe and Lynn Nadel’s masterpiece, The Hippocampus as a Cognitive Map (Oxford, U.K.: Oxford University Press, 1978), www.cognitivemap. net. See also Eleanor A. Maguire et al.,“Recalling Routes Around London: Activation of the Right Hippocampus in Taxi Drivers,” JN,vol. 17, no. 18 (Sept. 15, 1997), pp. 7103–10; Eleanor A. Maguire et al.,“Navigation Related Structural Change in the Hippocampi of Taxi Drivers,” PNAS, vol. 97, no. 8(April 11, 2000), pp. 4398–4403; Gabriel Kreiman et al.,“Category-Specific Visual Responses of Single Neurons in the Human Medial Temporal Lobe,” NNS, vol. 3, no.9 (Sept. 2000), pp. 946–53; Arne D. Ekstrom et al.,“Cellular Networks Underlying Human Spatial Navigation,” Nature, vol. 425 (Sept. 11, 2003), pp. 184–87; R. Quian Quiroga et al.,“Invariant Visual Representation by Single Neurons in the Human Brain,” Nature, vol. 435 (June 23, 2005), pp. 1102–7.

[14] JZ interview with Kenning, Society for Neuroeconomics annual meeting, Sept. 10,2006; Peter Kenning et al.,“The Role of Fear in Home-Biased Decision Making,”University of Münster, working paper (January 2007).

[15] Nicholas Epley et al.,“What Every Skeptic Should Know about Subliminal Persuasion,” Skeptical Inquirer, Sept./Oct. 1999, pp. 40–45; JZ interview with Piotr Winkielman, April 19, 2005; JZ interview with Zajonc, Oct. 12, 2005;Shlomo Benartzi et al.,“Company Stock, Market Rationality, and Legal Reform,”University of Chicago Law School working paper (July 2004), pp. 2, 8, 28; www.ici.org/stats/res/per12-01_appendix.pdf, p. 26; Merrill Lynch & Co. Inc., Form 11K, June 26, 2006, www.sec.gov/Archives/edgar/data/65100/000095012306008132/y22548e11vk.htm.

[16] Yoav Ganzach,“Judging Risk and Return of Financial Assets,” OBHDP, vol. 83,no. 2 (Nov. 2000), pp. 353–70; Michael J. Brennan et al.,“Alternative Factor Specifications, Security Characteristics, and the Cross-Section of Expected Stock Returns,” JFE, vol.49, no. 3 (Sept. 1998), pp. 345–73; Charles M. C. Lee and Bhaskaran Swaminathan,“Price Momentum and Trading Volume,” JF, vol. 55, no. 5(Oct. 2000), pp. 2017–69; Brad M. Barber and Terrance Odean,“All That Glitters”(March 2006), http://ssrn.com/abstract=460660; JZ interview with Zajonc, Oct. 12,2005.

[17] David Hirshleifer et al.,“Fear of the Unknown” (May 2004), http://public.kenan-flagler.unc.edu/faculty/zhangha/familiarity-5-30-2004-v2.pdf.

[18] This is not her real name, but the story is true.

[19] B. F. Skinner,“ ‘Superstition’ in the Pigeon,” JEP, vol. 38 (1948), pp. 168–72,http://psychclassics.yorku.ca/Skinner/Pigeon/; John Staddon, The New Behaviorism(Philadelphia: Psychology Press, 2001), pp. 54–68. While later research refuted some of Skinner’s observations, the basic finding still holds: that the pigeons behave“as if” their behavior causes them to be fed.

[20] The bet on the stock tables is adapted from Chip Heath and Amos Tversky,“Preference and Belief,” JRU, vol. 4 (1991), pp. 5–28. The dice experiment is Lloyd H. Strickland et al.,“Temporal Orientation and Perceived Control as Determinants of Risk-Taking,” JESP, vol. 2, no. 2 (1966), pp. 143–51; copy kindly provided to JZ by Roy Lewicki.

[21] Ellen J. Langer,“The Illusion of Control,” JPSP, vol. 32, no. 2 (Aug. 1975), pp.311–28; Rosa Bersabé and Rosario Martínez Arias,“Superstition in Gambling,”Psychology in Spain, vol. 4, no. 1 (2000), www.psychologyinspain.com/content/reprints/2000/3.pdf; see also Deborah Davis et al.,“Illusory Personal Control as a Determinant of Bet Size and Type in Casino Craps Games,” Journal of Applied Social Psychology, vol. 30, no. 6 (2000), pp. 1224–42. Retirement investors: William N. Goetzmann and Nadav Peles,“Cognitive Dissonance and Mutual Fund Investors,”Journal of Financial Research, vol. 20, no. 2 (1997), pp. 145–58.

[22] Robert E. Knox and James A. Inkster,“Postdecision Dissonance at Post Time,” JPSP,vol. 8, no. 4 (April 1968), pp. 319–23; Jonathan C.Younger et al.,“Postdecision Dissonance at the Fair,” PSPB, vol. 3, no. 2 (1977), pp. 284–87; Robert B. Cialdini,Influence (New York: William Morrow, 1993), pp. 57–59; Paul Rosenfeld et al.,“Decision Making,” Journal of Social Psychology, vol. 126, no. 5 (2001), pp.663–65.

[23] Ellen J. Langer,“The Illusion of Control,” JPSP, vol. 32, no. 2 (Aug. 1975), pp. 311–28; Ellen J. Langer,“The Psychology of Chance,” Journal for the Theory of Social Behaviour, vol. 7, no. 2 (Oct. 1977), pp. 185–207.

[24] Meghan Collins,“Traders Ward off Evil Spirits,” cnn.com, Oct. 29, 2003, http://money.cnn.com/2003/10/28/markets/trader_superstition /index.htm; William M.O’Barr and John M. Conley, Fortune and Folly (Homewood, Ill.: Business One Irwin, 1992), p. 155; Mark Fenton-O’Creevy et al., Traders (Oxford, U.K.: Oxford University Press, 2005), p. 87; Business Week, Sept. 3, 2001, p. 70; NYT, Oct. 15,2001, p. C1;www.globalcrossing.com/xml/news/2002/january/28.xml.

[25] Elizabeth M. Tricomi et al.,“Modulation of Caudate Activity by Action Contingency,” Neuron, vol. 41 (Jan. 22, 2004), pp. 281–92; JZ e-mail interviews with Delgado, Oct. 31 and Dec. 12, 2005; Arthur Aron et al.“Reward, Motivation,and Emotion Systems Associated with Early-Stage Intense Romantic Love,” Journal of Neurophysiology, vol. 94 (2005), pp. 327–37; Caroline F. Zink et al.,“Human Striatal Responses to Monetary Reward Depend on Saliency,” Neuron, vol. 42(May 13, 2004), pp. 509–17; JZ telephone interview with Caroline Zink, Jan. 18,2005. Caroline is the sister of Laurie Zink (see“I Know How Good It Would Feel,”Chapter Three, p. 34).

[26] Tim V. Salomons et al.,“Perceived Controllability Modulates the Neural Response to Pain,” JN, vol. 24, no. 32 (Aug. 11, 2004), pp. 7199–7203.

[27] Michael T. Rogan et al.,“Distinct Neural Signatures for Safety and Danger in the Amygdala and Striatum of the Mouse,” Neuron, vol. 46 (Apr. 21, 2005), pp. 309–20;JZ e-mail interview with Kandel and Rogan, Dec. 14, 2005.

[28] JZ e-mail interviews with Brad Russell, Jan. 10, 2005; Richard H. Thaler and Eric J.Johnson,“Gambling with the House Money and Trying to Break Even,” MS, vol. 36,no. 6 (June 1990), pp. 643–60.

[29] Amanda Bischoff-Grethe et al.,“The Context of Uncertainty Modulates the Subcortical Response to Predictability,” JCN, vol. 13, no. 7 (2001), pp. 986–93.

[30] Ellen J. Langer and Jane Roth,“Heads I Win, Tails It’s Chance,” JPSP, vol. 32, no.6 (Dec. 1975), pp. 951–55; Willem A. Wagenaar and Gideon B. Keren,“Chance and Luck Are Not the Same,” JBDM, vol. 1, no. 2 (1988), pp. 65–75; Nehemia Friedland,“On Luck and Chance,” JBDM, vol. 5, no. 4 (1992), pp. 267–82.

[31] www.ge.com/annual94/iba3a18.htm; http://pages.stern.nyu.edu/~lcabral/teaching/ge.pdf; Robert L. Conn et al.,“Why Must All Good Things Come to an End?”(Feb. 2004), http://ssrn.com/abstract=499310; Matthew T. Billett and Yiming Qian,“Are Overconfident Managers Born or Made?” (May 2006), http://ssrn.com/abstract=696301; Richard Roll,“The Hubris Hypothesis of Corporate Takeovers,”JB, vol. 59, no. 2 (Apr. 1986), pp. 197–216; Gilles Hilary and Lior Menzly,“Does Past Success Lead Analysts to Become Overconfident?” MS, vol. 52, no. 4 (April 2006), pp. 489–500; Vernon L. Smith et al.,“Bubbles, Crashes, and Endogenous Expectations in Experimental Spot Asset Markets,” Econometrica, vol. 56, no. 5 (Sept. 1988), pp. 1119–51; David P. Porter and Vernon L. Smith,“Stock Market Bubbles in the Laboratory,” Applied Mathematical Finance, vol. 1 (1994), pp.111–27.

[32] 1英尺≈0.3米。6英尺4英寸约为193厘米。——编者注

[33] JZ telephone interview with John Allman, Dec. 28, 2004; Stephanie Kovalchik and John Allman,“Measuring Reversal Learning,” C&E, vol. 20, no. 5 (2005), pp.714–28.

[34] J. Hornak et al.,“Reward-Related Reversal Learning after Surgical Excisions in Orbito-frontal or Dorsolateral Prefrontal Cortex in Humans,” JCN, vol. 16, no. 3(2004), pp. 463–78. Most of these patients had suffered minor brain damage as a result of corrective surgery for stroke, epilepsy, brain tumors, or head trauma.

[35] Alanna Nash, The Colonel (New York: Simon & Schuster, 2003), p. 322; Carolyn Abraham,“Diapers Keep Gamblers at Slots,” Ottawa Citizen, May 3, 1997, p. A1.

[36] Wayne C. Drevets et al.,“Subgenual Prefrontal Cortex Abnormalities in Mood Disorders,” Nature, vol. 386 (Apr. 24, 1997), pp. 824–27; Rita Carter, Mapping the Mind (Berkeley: University of California Press, 1999), p. 197; Rebecca Elliott et al.,“Dissociable Neural Responses in Human Reward Systems,” JN, vol. 20, no. 16 (Aug.15, 2000), pp. 6159–65; Edmund T. Rolls et al.,“Activity of Primate Subgenual Cingulate Cortex Neurons Is Related to Sleep,” Journal of Neurophysiology, vol. 90(2003), pp. 134–42.

[37] Ravi Dhar and William N. Goetzmann,“Bubble Investors” (Aug. 2006), http://ssrn.com/abstract=683366; JZ e-mail interview with Will Goetzmann, Nov. 9, 2005.

[38] Baruch Fischhoff and Ruth Beyth,“ ‘I Knew It Would Happen,’” OBHDP, vol.13 (1975), pp. 1–16; Baruch Fischhoff,“Hindsight Does Not Equal Foresight...”JEPHPP, vol. 1, no. 3 (1975), pp. 288–99; JZ telephone interview with Baruch Fischhoff, Sept. 21, 2005; remarks by Daniel Kahneman, panel discussion moderated by JZ, Oxford Programme on Investment Decision-Making, Saïd Business School,Oxford University, U.K. Oct. 22, 2004.

[39] Gary Rivlin,“The Madness of King George,” Wired (July 2002), www.wired.com/wired/archive/10.07/gilder.html; Jeanne Lee,“Crash Test,” MM, June 2000, p. 39;Pablo Galarza and Jeanne Lee,“The Sensible Internet Portfolio,” MM, Dec. 1999,p. 129. (Disclosure: In May 1999, JZ wrote a column for Money entitled“Baloney.com,” warning investors not to buy Internet stocks. But he did not stop his friend Pablo Galarza from recommending Ariba.)

[40] This example is inspired by Meir Statman and Jonathan Scheid,“Buffett in Foresight and Hindsight,” FAJ, vol. 58, no. 4 (July/Aug. 2002), pp. 11–18. The number of funds in existence at year-end 1996 is from www.icifactbook.org/pdf/06_fb_table06.pdf. The odds of flipping heads ten times in a row are 1 ⁄ 210, or 1 ⁄ 1024, or 0.001. Thus the probability against a given manager getting ten heads in a row is 99.9%. The probability that none of the 1,325 managers will flip ten heads in a row is .9991325,or 27.4%. Thus, the odds that at least one manager will get ten straight heads are 1.274, or 72.6%.

[41] www.cea.fn and Science, vol. 309 (Aug. 19, 2005), pp. 1170–71. The percentages of people’s certainty about the answers to these three questions are based on audience responses at speeches JZ has given over the past ten years.“The Inner Tube of Life,”Science, vol. 307 (Mar. 25, 2005), p. 1914.

[42] Baruch Fischhoff et al.,“Knowing with Certainty,” JEPHPP, vol. 3, no. 4 (1977), pp.552–64. A $1 bet in 1977, adjusted for inflation, is equivalent to roughly $3 today.

[43] 2006 EBRI Retirement Confidence Survey, www.ebri.org/surveys/rcs/2006/.

[44] This message applies to all the people who confidently attribute this proverb to Will Rogers. According to Steven Gragert, archival historian at the Will Rogers Memorial Museums in Claymore, Okla., there is no evidence that Rogers ever said it. Bartlett’s Familiar Quotations suggests that it is probably based on an aphorism by the 19thcentury American humorist Josh Billings:“It is better to know nothing than to know what ain’t so.”

[45] Carl-Axel S. Staël von Holstein,“Probabilistic Forecasting,” OBHDP, vol. 8(1972), pp. 139–58; J. Frank Yates et al.,“Probabilistic Forecasts of Stock Prices and Earnings,” OBHDP, vol. 49 (1991), pp. 60–79; Gustaf Törngren and Henry Montgomery,“Worse than Chance?” JBF, vol. 5, no. 3 (2004), pp. 148–53; Brad M.Barber and Terrance Odean,“The Courage of Misguided Convictions,” FAJ, vol.55, no. 6 (Nov./Dec. 1999);“Trading Is Hazardous to Your Wealth,” JF, vol. 55,no. 2 (Apr., 2000);“Individual Investors,” in Richard H. Thaler, ed., Advances in Behavioral Finance, vol. 2 (Princeton, N.J.: Princeton University Press, 2005), pp.543–69, www.odean.us; Richard Deaves et al.,“The Dynamics of Overconfidence”(Nov. 2005), http://ssrn.com/abstract=868970.

[46] Sarah Lichtenstein and Baruch Fischhoff,“Do Those Who Know More Also Know More about How Much They Know?” OBHDP, vol. 20, no. 2 (Dec. 1977),pp. 159–83; Dale Griffin and Amos Tversky,“The Weighing of Evidence and the Determinants of Confidence,” in HAB, pp. 230–49.

[47] Christopher D. Fiorillo et al.,“Discrete Coding of Reward Probability and Uncertainty by Dopamine Neurons,” Science, vol. 299 (March 21, 2003), pp.1898–1902; Peter Shizgal and Andreas Arvanitogiannis,“Gambling on Dopamine,”Science, vol. 299 (March 21, 2003), pp. 1856–58; Hugo D. Critchley et al.,“Neural Activity in the Human Brain Relating to Uncertainty and Arousal during Anticipation,” Neuron, vol. 29 (Feb. 2001), pp. 537–45.

[48] Gerd Gigerenzer, Adaptive Thinking (Oxford, U.K.: Oxford University Press, 2000),and“Fast and Frugal Heuristics,” in BHJDM, pp. 62–88; WSJ, Jan. 18, 1995, p. A1;U.S. Securities and Exchange Commission, Office of Municipal Securities, Cases and Materials (1999), www.sec.gov/pdf/mbondcs.pdf, pp. 59–100; Pensions & Investments, March 6, 2006, p. 28; WSJ, Sept. 20, 2006, p. C1; www.sdcera.org/ pdf/SDCERAInvestmentPerformanceAward.pdf.

[49] Hart Blanton et al.,“Overconfidence as Dissonance Reduction,” JESP, vol. 37 (2001),pp. 373–85; Robert H. Thouless,“The Tendency to Certainty in Religious Belief,”British Journal of Psychology, vol. 26 (1935), pp. 16–31, http://psychclassics.yorku.ca/Thouless/certainty.pdf.

[50] “Chairman’s Letter,” 1992 Berkshire Hathaway Inc. annual report, www.berkshirehathaway.com/letters/1992.html.

[51] Nicholas Dawidoff, The Fly Swatter (New York: Pantheon, 2002), pp. 212–13.

[52] JZ,“I Don’t Know, I Don’t Care,” cnn.com, Aug. 29, 2001, http://money.cnn.com/2001/08/29/investing/Zweig/.

[53] JZ telephone interview with Buffett, May 5, 2005; see also Peter D. Kaufman, ed.,Poor Charlie’s Almanack (Virginia Beach, Va.: Donning Publishers, 2005), pp. 43,95.

[54] Gary Belsky and Thomas Gilovich, Why Smart People Make Big Money Mistakes and How to Correct Them (New York: Fireside, 1999), pp. 172–73.

[55] JZ telephone interview with Baruch Fischhoff, Sept. 21, 2005; Baruch Fischhoff,“For Those Condemned to Study the Past: Heuristics and Biases in Hindsight,”JUU, pp. 335–51; Elizabeth Loftus,“Our Changeable Memories: Legal and Practical Implications,” NNS, vol. 4 (March 2003), pp. 231–34, www.seweb.uci.edu/faculty/loftus/.

[56] JZ telephone interview with Robin Hogarth, March 17, 2005; Robin Hogarth,Educating Intuition (Chicago: University of Chicago Press, 2001), pp. 81–91.

[57] S&P 500 return from Stocks, Bonds, Bills, and Inflation 2005 Yearbook (Chicago:Ibbotson Associates, 2005). Return adjusted for cash added and withdrawn is from Ilia D. Dichev,“What Are Stock Investors’ Actual Historical Returns?” (Jan. 2006),http://ssrn.com/abstract=544142. These three questions are inspired by Daniel Kahneman and Amos Tversky,“Intuitive Prediction,” in JUU, pp. 414–21.

[58] JZ interview with Christopher Davis, Dec. 8, 2005.

[59] Peter Lynch with John Rothchild, One up on Wall Street (New York: Penguin, 1990),pp. 18–19; Peter Lynch with John Rothchild, Beating the Street (New York: Simon &Schuster, 1993), pp. 152–59.

[60] Merck & Co. press release, Sept. 30, 2004, at www.merck.com; Merck & Co. Form 11-K, July 8, 2005, www.sec/gov/Archives/edgar/data/64978/000095014405007240/g96187e11vk.htm; N.Y. State Attorney General press release, Oct. 14, 2004, www.oag.state.ny.us/press/2004/oct/oct14a_04.html; Marsh & McLennan press releases,Nov. 9, 2004, and March 1, 2005, at www.marsh.com; Marsh and McLennan Cos.,Inc., Form 11-K, June 29, 2005, www.sec.gov/Archives/edgar/data/62709/00000627 0905000183/000006 2709-05-000183-index.htm; Lisa Meulbroek,“Company Stock in Pension Plans: How Costly Is It?” Journal of Law and Economics, vol. 48, no. 2(Oct. 2005), pp. 443–74; JZ e-mail interview with Meulbroek, Nov. 1, 2005; JZ e-mail interview with David Laibson, Oct. 8, 2005. See also JZ,“Don’t Try This with Your 401(k),” cnn.com, Nov. 4, 1999, http://money.cnn.com/1999/11/04/mailbag/mailbag/.Meulbroek’s calculation assumes that you have no savings outside of your 401(k).But even if your 401(k) is just half of your total net worth, a 25% allocation of your 401(k) to company stock for ten years would have an effective value of only 84 cents on the dollar.

[61] Rodger W. Bridwell, High-Tech Investing (New York: New York Times Book Co.,1983), pp. 12–13; Robert Metz, Future Stocks (New York: Harper & Row, 1982), pp.31–32.