不背降落伞跳下去更安全：搞笑实验背后的科学道理
Research published in a major medical journal concludes that a parachute is no more effective than an empty backpack at protecting you from harm if you have to jump from an aircraft.
一项发表在主流医学杂志上的研究得出结论，如果你必须从飞机上跳下，在保护你免受伤害方面降落伞并不比空背包更有效。
But before you leap to any rash conclusions, you had better hear the whole story.
不过在草率下结论之前，你最好先听一听整个故事。
The gold standard for medical research is a study that randomly assigns volunteers to try an intervention or to go without one and be part of a control group.
医学研究的金科玉律是一项研究，随机分配志愿者进行干预，或者不进行干预，作为其对照组。
For some reason, nobody has ever done a randomized controlled trial of parachutes.
出于某种原因，还没有人做过降落伞的随机对照试验。
In fact, medical researchers often use the parachute example when they argue they don't need to do a study because they're so sure they already know something works.
事实上，医学研究人员经常使用降落伞的例子来说明，当他们争辩说他们不需要做研究，因为确信他们已经知道这些规律。
Cardiologist Robert Yeh, an associate professor at Harvard Medical School and attending physician at Beth Israel Deaconess Medical Center, got a wicked idea one day.
哈佛大学医学院副教授、贝斯以色列女执事医疗中心主治医师、心脏病学家罗伯特·叶有一天突发奇想。
He and his colleagues would actually attempt the parachute study to make a few choice points about the potential pitfalls of research shortcuts.
他和他的同事们实际上会尝试降落伞研究，来就研究捷径的潜在缺陷给出另外一些选择。
They started by talking to their seatmates on airliners.
他们开始在飞机上与邻座交谈。
"We'd strike up a conversation and say, 'Would you be willing to be randomized in a study where you had a 50 percent chance of jumping out of this airplane with — versus without — a parachute?' " Yeh says.
我们会开始交谈，然后说，“'你愿意被随机分配到一项研究中吗?在这项研究中，你有50%的几率在有—或者没有—降落伞的情况下跳下飞机?’”叶说道。
Only a few people said yes to this outrageous invitation, and they were excluded for reasons of questionable mental health.
只有少数人接受了这一令人发指的邀请，他们因为精神健康问题而被排除在外。
The scientists had much better success asking members of their own research teams from Harvard, University of California, Los Angeles (Where Yeh's brother is a surgery professor), and University of Michigan (where a buddy works) about volunteering to participate in the experiment on other aircraft.
而问到科学家们自己的研究团队是否志愿参与其它飞行器上的实验时，结果则要成功得多，这些团队成员来自哈佛大学，加州大学，洛杉矶大学（叶教授的一个哥哥是一位外科教授）以及密歇根大学（他的一个朋友在那里工作）。
In all, 23 people agreed to be randomly given either a backpack or a parachute and then to jump from a biplane on Martha's Vineyard in Massachusetts or from a helicopter in Michigan.
总共有23人同意随机分配背包或降落伞，然后从马萨诸塞州玛莎葡萄园岛的一架双翼飞机或密歇根州的一架直升机上跳下。
Relying on two locations and only two kinds of aircraft gave the researchers quite a skewed sample.
依靠两个地点和两种飞机，研究人员得到了一个相当扭曲的样本。
But this sort of problem crops up frequently in studies, which was part of the point Yeh and his team were trying to make.
但是这种问题经常出现在研究中，这也是叶和他的团队想要表达的观点之一。
Still, photos taken during the experiment show the volunteers were only too happy to take part.
尽管如此，实验期间拍摄的照片显示，志愿者们非常乐意参加。
"I think people are laughing all of the way to the ground," Yeh says.
“我想，人们是一路笑到了地面上，”叶教授说道。
Oh, there's one important detail here.
噢，这里有一个重要的细节。
The drop in the study was about 2 feet total, because the biplane and helicopter were parked.
实验研究中的落差大概总共是2英尺，因为这架双翼飞机和直升机是停在地面上的。
Nobody suffered any injuries.
没有人会受到任何伤害。
Surprise, surprise.
没想到吧！
So it's technically true that parachutes offered no better protection for these jumpers than the backpacks.
所以，从技术上说降落伞并不能比背包给跳下的人们提供更多的保护。
"But, of course,
that is a ludicrous result," Yeh says.
“不过，显然，这是一个很荒谬的结果，”叶教授说道。
"The real answer is that that trial did not show a benefit because of the types of patients who were enrolled."
“因为参与实验的人员类型的缘故，真正的答案就是这种实验没有任何好处。”
If they had enrolled people at high risk for injury, that is people in flying aircraft, the results would have been quite different (not to mention unethical).
如果他们招募了受伤风险高的人，也就是乘坐飞机的人，结果会大不相同(更不用说不道德了)。
But something like this happens in everyday medical research.
然而，类似的情形还会发生在日常的医学研究中。
It's far too easy for scientists who have already anticipated the outcome of their research to cherry-pick patients and circumstances to achieve the results they expect to see.
科学家们往往太容易会提前预见到他们研究的结果，以至于刻意挑选患者和病情来达到他们期望见到的结果。
This research paper carried that idea to the ridiculous extreme.
这篇研究论文把这种想法推演到了极致。
The study's findings were published in the traditionally lighthearted Christmas issue of the medical journal, BMJ.
这项研究结果发表在一向轻松愉快的《英国医学杂志》圣诞节版上。
"It's a little bit of a parable, to say we have to look at the fine print, we have to understand the context in which research is designed and conducted to really properly interpret the results," Yeh says.
叶教授说:“这有点像个寓言，就是说我们必须仔细研究细节，我们必须理解研究设计和实施的背景，以便真正正确地解释研究结果。”
Scientists often read just the conclusion of a study and then draw their own conclusions that are far more sweeping than are justified by the actual findings.
科学家通常只阅读研究的结论，然后得出自己的结论，这些结论比实际发现所证明的要广泛得多。
This is a real problem in science.
而这却是科学中的一个真正问题所在。
"I know that people often don't look detailed enough into what is being investigated to know how to interpret the results of a trial," says Cecile Janssens, an epidemiology professor at Emory University.
埃默里大学流行病学教授塞西尔·詹森表示:“我知道，人们往往会对正在调查的东西不够详细，不知道如何解释试验结果。”
Janssens was delighted to come across the paper on Twitter.
詹森很高兴在Twitter上看到了这篇文章。
She says like a lot of research, its results are accurate as far as they go, but "the results can only be generalized to situations where people jump out of an aircraft within a few feet above the ground."
她说，就像很多研究一样，它的结果在一定程度上是准确的，但“这个结果只能推广到人们从离地面几英尺的飞机上跳下的情况。”
She plans to give this paper to her students with a straight face and see how long it takes for them to get the deeper points about scientific methodology buried in this absurd experiment.
她打算把这篇论文严肃地交给她的学生，看看他们要花多长时间才能从这个荒谬的实验中获得关于科学方法论的更深层次的观点。
"It will be unforgettable," she says — far better than assigning a straight-ahead scientific study.
“这将是令人难忘的，”她说——这比安排一项直截了当的科学研究要好得多。
Yeh is pleased to see that the fun he had with his colleagues is turning into a teaching tool.
叶教授很高兴看到他和他的同事们的乐趣变成了一种教学工具。
He also savors some of the more subtle lessons buried in the paper.
他还品味着论文中隐藏的一些更微妙的教训。
For example, the scientists attempted to submit it to a government registry of research studies, which is required for many studies involving human subjects.
例如，科学家们试图将其提交给政府研究注册中心，这是涉及人类受试者的许多研究所必需的步骤。
They chose one in Sri Lanka to reduce the risk that it would be discovered in advance, spoiling the joke.
他们选择了斯里兰卡的一个，以降低它被提前发现的风险，那破坏了这个笑话。
It was rejected.
论文被拒了。
"They thought that a trial conducted in this manner could not lead to scientifically valid evidence," he said.
他说:“他们认为以这种方式进行的实验不能得出科学上有效的证据。”
"They're right!" he adds with a laugh.
“他们是对的！”他笑着补充道。
In fact, the paper acknowledges that the research team members cracked themselves up so much that "all authors suffered substantial abdominal discomfort from laughter."
事实上，这篇论文承认，研究小组成员笑得太过开怀，以至于“所有的作者都因为笑而感到腹部不适”。
"Our greatest accomplishment from all of this was we felt very good that we were able to cite Sir Isaac Newton in the paper," he says.
他表示:“我们从这一切中取得的最大成就是，能够在论文中引用艾萨克·牛顿爵士的话，我们感到非常高兴。”
They referred to Newton's classic 1687 paper establishing the law of gravity.
他们参考了牛顿1687年的经典论文《万有引力定律》。
Yes, gravity is a law.
是的，重力是一个定律。
Mess with it at your own risk.
违反它就得自食其果。
对于这次搞笑实验的结果，朋友们有什么看法呢？欢迎给amber留言哦！
感谢关注
跟amber一起看世界