When hundreds of Californians invaded the state capitol last week to demand the right not to vaccinate their kids, they were playing out a very modern conflict: science versus belief systems. Scientists tell parents that vaccinations are safe. But many parents prefer to trust their gut instinct that they’re not safe. This dialogue of the deaf is becoming the norm. Increasingly, people make their own decisions on health and diet, instead of outsourcing them to scientists, doctors or governments.
不久前，数百名美国加州人闯入州议会大厦，要求拥有不让自己的孩子接种疫苗的权利，他们演绎了一场极为现代的冲突——科学vs观念体系。科学家告诉家长接种疫苗是安全的，但许多家长宁愿相信自己的直觉——接种疫苗不安全。这种鸡同鸭讲式的对话已成常态。人们在健康和饮食方面越来越自作主张，而不是相信科学家、医生或政府。
If you want to change people’s behaviour, don’t recite science at them, says Alan Dangour, nutritionist at the London School of Hygiene and Tropical Medicine (LSHTM). Rather, to nudge people to better decisions, we need to understand how they decide. Behavioural economics has identified cognitive biases that influence our decisions about money. Here are some biases and misjudgments that shape decisions on health and diet:
伦敦卫生暨热带医学院(London School of Hygiene & Tropical Medicine)营养学家阿伦•丹古尔(Alan Dangour)表示，如果你想改变人们的行为，不要跟他们大讲科学道理。相反，想劝人们作出更好的决定，我们需要去了解他们是怎么做决定的。行为经济学已发现多种影响人类消费决定的认知偏见。以下是一些影响人们决定健康和饮食方式的偏见和错误观念：“‘Natural’ is good.”
“‘天然的’就是好的”
When faced with complex problems, people often resort to a heuristic: a pragmatic, simplified mental shortcut. A common shortcut is to use labels such as “natural”, “organic”, “local” or “homeopathic” as proxies for healthy. Conversely, “artificial” gets equated with unhealthy. This heuristic appeals partly because it relies on words. Not everyone understands science but we all know language.
当面对复杂问题时，人们往往会采用启发法(heuristic)，这是一种务实、简单化的心理捷径(mental shortcut)。常见的捷径之一是使用“天然”、“有机”、“本地”或“顺势疗法”等标签代表健康。反之，“人造的”就等同于不健康的。这种启发法之所以具有吸引力，部分在于它依靠文字。不是人人都懂科学，但所有人都懂语言。Sometimes, natural actually is good. The World Health Organisation announced last month that the world’s most common weedkiller, glyphosate, can probably cause cancer. But often natural isn’t good. For instance, homeopathy is ineffective for treating any medical condition, concluded Australia’s National Health and Medical Research Council last month, echoing a report for Britain’s House of Commons in 2010.
有时天然的确是好的。世界卫生组织(WHO)在今年3月宣布，全球最常见的除草剂草甘膦可能会致癌。但多数情况下，天然的并不好。比如，澳大利亚国家健康与医学研究理事会(National Health and Medical Research Council)也在今年3月发表了一个结论，顺势疗法对治疗任何疾病都毫无疗效，附和了2010年提交到英国下议院的一份报告的结论。Likewise, “natural” organic foods aren’t more nutritious than other foods, said researchers from the LSHTM, after reviewing 50 years of studies. A Stanford analysis of 237 studies concurred.
此外，伦敦卫生暨热带医学院的研究人员回顾了50年来的研究成果之后，表示“天然”有机食品并不比其他食物更有营养。斯坦福大学(Stanford)从237项研究中也得出了同样结论。“All ‘scientific’ studies are equal.”
“所有‘科学的’研究都是平等的”In fact, as Eula Biss explains in her book On Immunity, any single study in medicine is meaningless. To quote medical researcher John Ioannidis: “Most published research findings are false.” A single study might have been small, poorly conducted or produce findings that are due simply to chance. “What matters,” says Ioannidis, “is the totality of evidence.” That’s why the gold standard of medical research is the meta-study, such as the ones cited above on organic food, which aggregate previous research on a topic. Nonetheless anti-vaccinators still cite one now-retracted study of 12 children, published by Andrew Wakefield and others in 1998, which suggested that vaccinating children might cause autism.
事实上，正如尤拉•比斯(Eula Biss)在其著作《免疫》(On Immunity)中所述，医学上的任何单一研究都毫无意义。引用医学研究人员约翰•约安尼季斯(John Ioannidis)的一句话：“大多数业已发表的研究成果都是虚假的。”单一研究有可能规模很小，操作不当，或者仅仅是偶然状况下得出的结果。约安尼季斯说：“重要的是所有证据的总和。”这就是为什么医学研究的黄金标准是元研究，它集合了关于某一课题的以往研究，比如前文中提到的关于有机食品的研究。尽管如此，反疫苗者仍引用一份已经撤销的关于12名儿童案例的研究报告，该研究由安德鲁•韦克菲尔德(Andrew Wakefield)与其他研究人员在1998年发布，他们认为儿童接种疫苗可能引起自闭症。People seize on single studies because we are bad at weighing quantities. We struggle to distinguish between “a little” and “lots”. That’s also why people panic when “traces” of “toxins” show up in a product — traces of mercury in vaccines, for instance. But quantity is crucial. Biss quotes a toxicologists’ adage: “The dose makes the poison.”
人们之所以会抓住一项研究不撒手，是因为我们非常不善于权衡数量。我们很难区分出“少量”与“大量”之间的差别。这也是为什么当某一产品显现出“有毒迹象”时人们会恐慌，比如当疫苗中含有汞成分时。但分量才是关键因素。比斯引用了一句毒理学格言：“只要剂量足，万物皆有毒。”(The dose makes the poison)“Self-denial is good for you.”
“弃绝自我是有益的”This religious notion survives in today’s “detox diets”, which often entail forswearing everything except selected “natural” products such as juices. In fact, “sinful” things such as wine, chocolate and coffee (a rare legal, mind-altering, performance-enhancing drug) are healthy in small quantities.
这种宗教观念在如今的“节食排毒”(detox diets)饮食理念中得到延续。该饮食方式通常需要戒绝一切食物，只食用果汁之类的选定的“天然”产品。事实上，少量食用“罪恶的”食物对健康有利，比如葡萄酒、巧克力和咖啡（咖啡是一种少有的合法、会改变精神、提高效率的药品）。Confirmation bias
确认偏见Our main source of information on health today is Google. However, you can find anything online, and most people gravitate to websites that confirm their beliefs.
我们今天关于健康的信息主要来自谷歌(Google)。但是网上可以找到各种各样的说法，而且绝大多数人倾向于那些能证明他们观念的网站。Ambiguity aversion
模糊厌恶People like certainty. In health, that’s rarely available. Authorities sometimes change their minds: for instance, the US government is expected to announce soon that high-cholesterol foods are OK after all.
人们喜欢确定性，但在健康方面确定性很难得到。相关部门不时会改变观点，比如美国政府预计很快将宣布，高胆固醇食物是没有问题的。Instead of seeking certainty, we should make decisions on the balance of probability: vaccinating your kids is very probably smart. But probability feels too ambiguous to be reassuring.
在健康问题上，我们不该去追求确定性，而是应该基于概然性来做出决定：给你的孩子接种疫苗非常可能是个明智的决定。但可能性听起来太模棱两可，无法让人放心。Rare, spectacular kinds of death grip our imaginations.
我们的想象里充斥着各种稀奇的、耸人听闻的死法People fret about terrorists, sharks, Ebola and plane crashes because of the availability heuristic. The more available a piece of information is to the memory — a terrorist attack, say — the more likely it is to influence our decisions. In fact, terrorism kills fewer people than sitting at a desk.
人们担心恐怖分子、鲨鱼、埃博拉(Ebola)和飞机失事是因为它们具有“可得性启发”(availability heuristic)。一条信息——比如恐怖袭击——对记忆的启发越多，对我们做决定的影响很可能就越大。事实上，死于恐怖主义的人远远少于死在办公桌前的人。Optimism bias
乐观倾向Smokers know that smoking is addictive and lethal. But they tend to believe it will only enslave and kill other smokers, says Jody Sindelar, professor at the Yale School of Public Health. In general, people downplay their unhealthy habits, preferring instead to blame disease on factors beyond their control: their genes or environmental factors such as mobile phones or radiation. You can see why.
耶鲁大学(Yale)公共卫生学院(School of Public Health)的乔迪•辛德拉尔教授(Jody Sindelar)表示，吸烟者知道吸烟会上瘾，还会致命，可他们往往相信香烟只会征服和杀死其他吸烟者。一般来说，人们会低估自己的不良习惯的影响，而偏向将病因归结于那些他们无法控制的因素，比如基因或手机、辐射等环境因素。个中原因可想而知。Present bias
重视眼前的倾向We value the present above the future. The best time to quit smoking is therefore always tomorrow, says Sindelar.
辛德拉尔说，比起未来，我们更看重眼前，所以戒烟的最佳时机永远是明天。Scientists and governments need to change tack. Instead of bombarding people with science, they should design policies that use our cognitive biases. One obvious technique is advertising. A gorgeous ad showing a mother cuddling a baby who is being vaccinated might be worth 10,000 scientific studies. Sindelar suggests other methods:
科学家和政府需要改变策略。不应该用科学道理去轰炸民众，而是应该根据我们的认知偏差来设计政策。最易行的手法就是广告。比如拍摄一位母亲怀里抱着正在接种的小宝宝，这样一支动人的广告或许比得上一万个科学研究。辛德拉尔还提出了其他方法：● Reminders: on sunny days, send people messages suggesting they put on sunscreen.
●提醒：在阳光明媚的日子，给人们发消息建议他们涂上防晒霜。● Pre-commitments: encourage people to bet that they will lose specific amounts of weight.
●预承诺：鼓励人们打赌他们能够减掉多少体重。● Financial incentives: pay people to give up smoking.
●财务奖励：以奖金鼓励人们戒烟。These nudges could do more than scientific findings to change behaviour. In today’s low-trust world, science is in the doghouse with most other authorities.
这些温和的规劝比科学发现更能改变人类行为。在如今这个低信任度的世界，科学与其他多数权威都已被打入冷宫。