多樣化社區科普也要講究方法

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，數百名美國加州人闖入州議會大廈，要求擁有不讓自己的孩子接種疫苗的權利，他們演繹了一場極爲現代的衝突——科學vs觀念體系。科學家告訴家長接種疫苗是安全的，但許多家長寧願相信自己的直覺——接種疫苗不安全。這種雞同鴨講式的對話已成常態。人們在健康和飲食方面越來越自作主張，而不是相信科學家、醫生或政府。

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:

倫敦衛生暨熱帶醫學院(London School of Hygiene & Tropical Medicine)營養學家阿倫•丹古爾(Alan Dangour)表示，如果你想改變人們的行爲，不要跟他們大講科學道理。相反，想勸人們作出更好的決定，我們需要去了解他們是怎麼做決定的。行爲經濟學已發現多種影響人類消費決定的認知偏見。以下是一些影響人們決定健康和飲食方式的偏見和錯誤觀念：

“‘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.

當面對複雜問題時，人們往往會採用啓發法(heuristic)，這是一種務實、簡單化的心理捷徑(mental shortcut)。常見的捷徑之一是使用“天然”、“有機”、“本地”或“順勢療法”等標籤代表健康。反之，“人造的”就等同於不健康的。這種啓發法之所以具有吸引力，部分在於它依靠文字。不是人人都懂科學，但所有人都懂語言。

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.

有時天然的確是好的。世界衛生組織(WHO)在今年3月宣佈，全球最常見的除草劑草甘膦可能會致癌。但多數情況下，天然的並不好。比如，澳大利亞國家健康與醫學研究理事會(National Health and Medical Research Council)也在今年3月發表了一個結論，順勢療法對治療任何疾病都毫無療效，附和了2010年提交到英國下議院的一份報告的結論。

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，倫敦衛生暨熱帶醫學院的研究人員回顧了50年來的研究成果之後，表示“天然”有機食品並不比其他食物更有營養。斯坦福大學(Stanford)從237項研究中也得出了同樣結論。

“All ‘scientific’ studies are equal.”

“所有‘科學的’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.

事實上，正如尤拉•比斯(Eula Biss)在其著作《免疫》(On Immunity)中所述，醫學上的任何單一研究都毫無意義。引用醫學研究人員約翰•約安尼季斯(John Ioannidis)的一句話：“大多數業已發表的研究成果都是虛假的。”單一研究有可能規模很小，操作不當，或者僅僅是偶然狀況下得出的結果。約安尼季斯說：“重要的是所有證據的總和。”這就是爲什麼醫學研究的黃金標準是元研究，它集合了關於某一課題的以往研究，比如前文中提到的關於有機食品的研究。儘管如此，反疫苗者仍引用一份已經撤銷的關於12名兒童案例的研究報告，該研究由安德魯•韋克菲爾德(Andrew Wakefield)與其他研究人員在1998年發佈，他們認爲兒童接種疫苗可能引起自閉症。

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.”

人們之所以會抓住一項研究不撒手，是因爲我們非常不善於權衡數量。我們很難區分出“少量”與“大量”之間的差別。這也是爲什麼當某一產品顯現出“有毒跡象”時人們會恐慌，比如當疫苗中含有汞成分時。但分量纔是關鍵因素。比斯引用了一句毒理學格言：“只要劑量足，萬物皆有毒。”(The dose makes the poison)

“Self-denial is good for you.”

“棄絕自我是有益的”

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.

這種宗教觀念在如今的“節食排毒”(detox diets)飲食理念中得到延續。該飲食方式通常需要戒絕一切食物，只食用果汁之類的選定的“天然”產品。事實上，少量食用“罪惡的”食物對健康有利，比如葡萄酒、巧克力和咖啡（咖啡是一種少有的合法、會改變精神、提高效率的藥品）。

Confirmation bias

確認偏見

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.

我們今天關於健康的信息主要來自谷歌(Google)。但是網上可以找到各種各樣的說法，而且絕大多數人傾向於那些能證明他們觀念的網站。

Ambiguity aversion

模糊厭惡

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.

人們喜歡確定性，但在健康方面確定性很難得到。相關部門不時會改變觀點，比如美國政府預計很快將宣佈，高膽固醇食物是沒有問題的。

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.

在健康問題上，我們不該去追求確定性，而是應該基於概然性來做出決定：給你的孩子接種疫苗非常可能是個明智的決定。但可能性聽起來太模棱兩可，無法讓人放心。

Rare, spectacular kinds of death grip our imaginations.

我們的想象裏充斥着各種稀奇的、聳人聽聞的死法

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.

人們擔心恐怖分子、鯊魚、埃博拉(Ebola)和飛機失事是因爲它們具有“可得性啓發”(availability heuristic)。一條信息——比如恐怖襲擊——對記憶的啓發越多，對我們做決定的影響很可能就越大。事實上，死於恐怖主義的人遠遠少於死在辦公桌前的人。

Optimism bias

樂觀傾向

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.

耶魯大學(Yale)公共衛生學院(School of Public Health)的喬迪•辛德拉爾教授(Jody Sindelar)表示，吸菸者知道吸菸會上癮，還會致命，可他們往往相信香菸只會征服和殺死其他吸菸者。一般來說，人們會低估自己的不良習慣的影響，而偏向將病因歸結於那些他們無法控制的因素，比如基因或手機、輻射等環境因素。箇中原因可想而知。

Present bias

重視眼前的傾向

We value the present above the future. The best time to quit smoking is therefore always tomorrow, says Sindelar.

辛德拉爾說，比起未來，我們更看重眼前，所以戒菸的最佳時機永遠是明天。

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:

科學家和政府需要改變策略。不應該用科學道理去轟炸民衆，而是應該根據我們的認知偏差來設計政策。最易行的手法就是廣告。比如拍攝一位母親懷裏抱着正在接種的小寶寶，這樣一支動人的廣告或許比得上一萬個科學研究。辛德拉爾還提出了其他方法：

● Reminders: on sunny days, send people messages suggesting they put on sunscreen.

●提醒：在陽光明媚的日子，給人們發消息建議他們塗上防曬霜。

● Pre-commitments: encourage people to bet that they will lose specific amounts of weight.

●預承諾：鼓勵人們打賭他們能夠減掉多少體重。

● Financial incentives: pay people to give up smoking.

●財務獎勵：以獎金鼓勵人們戒菸。

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.

這些溫和的規勸比科學發現更能改變人類行爲。在如今這個低信任度的世界，科學與其他多數權威都已被打入冷宮。