Out of the crooked¹ timber of humanity, no straight thing was ever made. This famous remark of the German philosopher, Immanuel Kant, is particularly relevant to economists². “Homo economicus” is far-sighted, rational and self-interested. Real human beings are none of these things. We are bundles of emotions, not calculating machines. This matters.

“人性这根曲木，绝然造不出任何笔直的东西。”经济学家尤其应该听听德国哲学家伊曼努尔•康德(Immanuel Kant)的这句名言。“经济人”有远见、理性而且自私。真正的人跟经济人完全不一样。我们感情充沛，不是精于计算的机器。这非常关键。

The World Bank’s latest World Development Report examines this territory. It notes that “behavioural economics” alters our view of human behaviour in three ways: first, most of our thinking is not deliberative, but automatic; second, it is socially conditioned; and, third, it is shaped by inaccurate³ mental models.

世界银行(World Bank)在其发布的最新一期《世界发展报告》(World Development Report)中研究了该领域。它指出，“行为经济学”从3个方面改变了我们对人类行为的看法：首先，我们的大部分想法并非经过深思熟虑，而是自动产生的；其次，它受到社会的制约；第三，它脱胎于不精确的思维模式。

The Nobel laureate, Daniel Kahneman, explored the idea that we think in two different ways in his 2011 bookThinking, Fast and Slow. The need for an automatic system is evident. Our ancestors did not have the time to work out answers to life’s challenges from first principles. They acquired automatic responses and a cultural predisposition towards rules of thumb. We inherited both these traits. Thus, we are influenced by how a problem is framed.

诺贝尔奖得主丹尼尔•卡内曼(Daniel Kahneman)在其2011年出版的《思维，快慢有别》(Thinking, Fast and Slow)一书中探讨了人类有两种不同思维方式的观点。拥有一种自动反应的思维体系显然是必要的。我们的祖先没时间从基本原则中寻找解决生活挑战的办法。他们获得了自动反应的本领，也形成了听从经验法则的文化倾向。这两种特质我们都继承了。因此，我们会受问题提出方式的影响。

Another characteristic is “confirmation⁴ bias⁵” — the tendency to interpret new information as support for pre-existing beliefs. We also suffer from loss aversion, fierce resistance to losing what one already has. For our ancestors, on the margin⁶ of survival, that made sense.

另一个特征是“确认偏误”(confirmation bias)——即将新信息解读为能够支持已有观点的倾向。我们还有“厌恶损失”(loss aversion)的倾向，即强烈抗拒失去我们已经拥有的东西。对我们只能勉强维持生存的祖先来说，这种倾向非常明智。

The fact that humans are intensely social is clear. Even the idea that we are autonomous⁷ is itself socially conditioned. We are also far from solely⁸ self-interested. A bad consequence of the power of norms is that societies may be stuck in destructive patterns of behaviour. Nepotism⁹ and corruption¹⁰ are examples. If they are entrenched¹¹, it may be difficult (or dangerous) for individuals not to participate. But social norms can also be valuable. Trust is a valuable norm. It rests on one of humanity’s strongest behaviours: conditional¹² co-operation. People will punish free-riders even when it costs them to do so. This trait strengthens groups and so must raise members’ ability to survive.

人类具有强烈的社会性，这是显而易见的。就连我们是独立的个体这个想法本身，也是受到社会制约的。我们也绝非完全自私。社会规范的强大威力带来的一个糟糕后果是，社会可能陷入消极的行为模式。裙带关系和腐败就是例证。如果裙带关系或腐败根深蒂固，个人不参与其中或许就很困难（或危险）。但社会规范也可能是有用的。信任是一种有用的规范。它依赖于人类最擅长的行为之一：有条件的合作。人们将会惩罚搭便车者，即便惩罚他们要付出代价。这种特质增强了团队的凝聚力，从而肯定会提高团队成员的生存能力。

Mental models are essential. Some seem to be inbuilt; and some can be damaging — as well as productive. Ideas about “us” and “them”, reinforced by social norms, may well lead to results that range from the merely unfair to the catastrophic. Equally important may be mental models that create self-fulfilling expectations of who will succeed and who will fail. There is evidence, notes the WDR, that mental models rooted in history may shape people’s view of the world for centuries: caste is an example. Such mental models survive because they are reproduced socially and become part of the automatic rather than the deliberative system. They influence not just our perceptions of others, but perceptions of ourselves.

思维模式非常关键。有些似乎是人内在固有的，此外，有些模式可能同时具有创造性和破坏性。关于“我们”和“他们”的观念如果经过社会规范的强化，很可能导致各种各样的结果，从仅仅是不公平的，到酿成灾难的。有些思维模式能够产生有关谁将成功、谁将失败的预期（并且这种预期具有自我实现的能力），这些思维模式同样重要。《世界发展报告》指出，有证据表明，有深厚历史根源的思维模式可能决定人们数百年的世界观：种姓制度就是一个例子。此类思维模式之所以经久不衰，是因为它们在社会上不断繁殖，成为了一种自动（而非经过深思熟虑）的反应。它们不仅影响我们对其他人的看法，还影响我们对自己的看法。

To illustrate¹³ the relevance¹⁴ of these realities, the report analyses the policy challenges of poverty, early childhood development, household finance, productivity, health and climate change.

为了表明这些研究与现实密切相关，该报告还分析了贫穷、幼儿期发展、家庭财务、生产率、健康和气候变化的政策挑战。

On household finance, for example, the report notes that it makes a difference whether would-be borrowers are told explicitly¹⁵ how much more expensive is a payday loan than an equivalent loan on a credit card. Revealing the status of low-caste boys in a mixed-caste classroom depresses the performance of students from lower castes compared with what happens if caste is not revealed. The boys respond to how they are presented. Again, poverty is not just a lack of material resources:it undermines the ability to think deliberately¹⁷.

例如，在家庭财务方面，该报告指出，潜在借款者是否被明确告知发薪日贷款(payday loan,一种小额、短期的高利贷,用于贷款人下一次发薪之前临时急用——译者注)与等额信用卡贷款相比有多么昂贵，结果将大为不同。如果在一个种姓混杂的班级里让大家知道谁是低种姓学生，那么低种姓学生的表现就会不如其身份没有暴露时的表现。别人如何介绍自己，会影响这些男孩的表现。同样，贫穷不仅仅是物质资源的匮乏：它还削弱一个人审慎思考的能力。

The way people think may also affect their productivity. An example is the benefits of contracts that penalise a worker for failing to meet the output targets she has chosen for herself. This is a way of closing the gap between good intentions and actual performance, such as when we agree to put money in the swearbox when we curse. We often disappoint ourselves. We may wish to bind¹⁸ ourselves to better behaviour, like Odysseus to his mast.

人们的思考方式也可能影响他们的生产效率。一个例子是，签订这样的合同有不错的效果：约定工人如果未能完成自己选择的产量目标就会受到惩罚。要消除良好意愿与实际表现的差距，这是一种方法，比如我们同意只要我们骂人就要往罚款箱里投钱。我们常常让自己失望。我们可能希望约束自己、迫使自己表现得更好，就像奥德修斯(Odysseus)让人把自己捆在桅杆上（以抵挡海妖歌声的诱惑）那样。

Health creates vital examples. One is the importance of mental models. An obvious one is the anti-vaccination hysteria. Another, illustrated¹⁹ by the WDR, is the tendency of poor women to believe that the right treatment for diarrhoea is to cut fluid intake²⁰, to stop their child “leaking”. Another is the tendency of people to be put off by even a very small charge for health products. The explanation for the reluctance²¹ to pay anything may, it suggests, be because free provision underpins²² the norm that everybody ought to take the medicine.

健康领域产生了一些重要的例子，其中之一是思维模式的重要性。一种明显的思维模式是非理性地反对接种疫苗。《世界发展报告》举出的另一种思维模式是，贫穷的妇女往往认为，腹泻的正确治疗方法是减少液体的摄入，这样他们的孩子就不再“拉稀”。还有一种思维模式是，人们往往不愿购买收费的健康产品，哪怕金额极低。报告称，人们之所以一分钱都不愿花，可能是因为，免费提供才符合有难同当的社会规范。

These then are intriguing²³ examples of a more nuanced approach to policy. Another area where a narrow focus only on incentives²⁴ is likely to be misleading is financial regulation. Many economists believe that dysfunctional behaviour in financial markets is due solely to distorted incentives: deposit insurance, the perception that institutions are “too big to fail” and a host of other explicit¹⁶ and implicit²⁵ subsidies²⁶. Equally important, however, are behavioural norms, such as the view that the primary duty of bankers is to themselves not their customers; or inappropriate mental models, such as the widespread pre-crisis belief that house prices could not fall across the US. Regulation needs to be built on an understanding of such human frailties²⁷. It must focus on norms and groupthink, as well as on distorted incentives.

因此这些有趣的例子表明了政策手段有必要更加细致。另一个关键领域是金融监管，在这一领域中，如果仅仅关注于激励就可能导致误解。许多经济学家相信，金融市场中的失灵行为完全是扭曲的动机造成的，比如：存款保险、机构“太大而不能倒闭”的观念，以及其他众多显性和隐性补贴。然而，同样重要的是社会行为规范，比如认为银行家主要应该对他们自己、而不是客户负责的观点；或者不适当的思维模式，比如危机前人们普遍认为，美国的房价不会普跌。监管需要建立在了解此类人性弱点的基础之上。它必须不仅关注于扭曲的动机，还关注于社会规范和群体迷思(groupthink)。

How far should policy be based on these perceptions, particularly since those who make policy are, as the WDR admits, prone²⁸ to all sorts of biases²⁹ in their own decision-making? We are all made of Kant’s crooked timber: nobody has godlike wisdom and self-control.

政策应该在多大程度上以这些观念为基础？尤其是正如《世界发展报告》承认的那样，那些制定政策的人士往往对他们自己的决策存在各种各样的偏见。我们全都由康德所说的“曲木”制成：没有人有上帝那样的智慧和自制力。

Yet policy must be made. It is surely better to make well-informed and realistic policy than base it on a grossly simplistic view of our true capacities. Moreover, nudging people in the direction they already want to go — by encouraging them to save, learn, behave healthily or bring up their children better — is hardly a gross violation³⁰ of liberty. Yet encouragement should not slide too easily into coercion³¹. Adults are not to be treated as children. That, too, is a social norm and quite a fundamental one.

然而政策是必须制定的。充分了解相关信息、从现实出发制定政策，肯定要比基于对我们真实能力的过分简单化理解制定政策要好。此外，通过鼓励人们储蓄、学习、过健康生活或更好地抚育子女，推动人们朝他们本来就希望的方向前进，这不能说是严重侵犯自由。然而，鼓励不应轻易地演变为强制。不应把成年人当做小孩对待。那也是一种社会规范，而且还是相当根深蒂固的一种。