经济学家教你如何坚持去健身房

If you’re like a lot of Americans, one of your New Year’s resolutions is to work out more. If you’re like a lot of Americans, you’ll join a gym this January as part of that plan. And if you’re like a lot of Americans, you won’t go very much.
你是不是和很多美国人一样，新年规划之一是要多锻炼，并在今年1月为此办了一张健身卡，但实际上却不会常去？

Our overoptimism about how much we will work out has been the subject of academic research. Nearly a decade ago, the economists Stefano DellaVigna and Ulrike Malmendier published “Paying Not to Go to the Gym,” a paper in which they found that members at three Boston gyms went an average of 4.3 times a month. With monthly membership fees of just over $70, that meant an average of $17 per visit — well above the $10 charge to work out as a nonmember.
关于我们对自己会进行多少锻炼过分乐观的问题，一直是学术研究的对象。近10年前，经济学者斯特凡诺·德拉维尼亚(Stefano DellaVigna)和乌尔丽克·马尔门迪尔(Ulrike Malmendier)发表了一篇名为《付了钱却不去健身》(Paying Not to Go to the Gym)的文章。他们在研究中发现，波士顿三家健身房的会员平均每月去4.3次。在月会员费略高于70美元（约合440元人民币）的情况下，这意味着每去一次平均花费17美元，远高于非会员锻炼一次10美元的收费。

So why didn’t they just pay per visit? Because they overestimated how often they would go. The authors surveyed gym members who, on average, said they would work out about 9.5 times a month, more than twice the actual attendance observed in the study. People remained in denial about their gym attendance even after they’d stopped going entirely: On average, nonattending gym members did not cancel until 2.3 months after their last visit, paying for $187 worth of completely unused gym access.
那么，他们为什么不每次单独交钱呢？因为他们高估了自己去健身的频率。文章作者对健身房会员做了一项调查。受访者希望平均每月锻炼9.5次，是研究中观察到的实际次数的两倍多。甚至在彻底不去了以后，人们也依然不愿承认自己去健身房的实际频率。不再去的人注销会员资格的时间，与他们最后一次去平均相隔2.3个月，也就是说他们花187美元买的服务根本没用过。

Lightly used gym memberships aren’t limited to Boston. The last annual shareholder filing from Town Sports International, the parent company of New York Sports Clubs, showed the company had 497,000 members making 29.1 million annual visits; that is, the average member visited five times a month.
健身房会员资格利用不充分的情况并不仅限于波士顿。纽约运动俱乐部(New York Sports Clubs)的母公司城镇运动国际(Town Sports International)最新的一份年度股东备案文件显示，公司有49.7万名会员，全年的健身人次是2910万，即平均每名会员每月去五次。

Since pay-now, work out-later isn’t working as a strategy, economists have been searching for other solutions to get people into the gym more often.
由于“现在付钱、以后锻炼”的策略不起作用，经济学家们一直在寻找其他解决方案，以提高人们去健身房的频率。

“We describe a field experiment measuring the impact of bundling instantly gratifying but guilt-inducing ‘want’ experiences (enjoying page-turner audiobooks) with valuable ‘should’ behaviors providing delayed rewards (exercising),” wrote the economists Katherine Milkman, Julia Minson and Kevin Volpp of Wharton in a 2013 research paper. They gave Penn undergraduates free iPods loaded with audiobooks of their choice, but told them they could listen to them only at the gym.
“我们描述的是一项实地试验，衡量将‘想做’的事情和‘应该做’的事情结合在一起的效应。‘想做’的是当时令人高兴但却会引起内疚的事情（听引人入胜的有声读物），而‘应该做’的是有价值且会在日后带来回馈的事情（锻炼），”沃顿商学院的经济学者凯瑟琳·米尔克曼(Katherine Milkman)、朱莉娅·明森(Julia Minson)和凯文·沃尔普(Kevin Volpp)在2013年的一篇研究论文中写道。他们给宾夕法尼亚大学的本科生提供免费的iPod，里面有学生自己选择的有声读物，但又要求学生，只能在健身房里听。

This worked for a while: The undergrads given the iPods went to the gym about 50 percent more often than others who were just given a Barnes & Noble gift card to spend as they pleased. (A third group, given a book iPod to take home but encouraged to listen only at the gym, placed in between the other two.) But that lasted for about seven weeks. Thanksgiving break came, and the students returned to school having fallen out of love with their audiobooks; they no longer worked out more than their peers in the control group.
这个办法一度奏效：得到了iPod的本科生去健身房的频率，比只拿到了巴诺书店(Barnes & Noble)礼品卡且可以自行决定其用途的学生高出了大约50%。（还有一个小组的学生也得到了有声读物。研究人员让他们把有声读物存在自己家里的iPod上，但鼓励他们只在健身房听。这组学生去健身房的频率介于另外两组之间。）但这种情况只持续了大约七周。感恩节假期结束后，返校的学生已经不再受到有声读物的诱惑，锻炼的频率也不再高于控制组的成员。

“It was a bummer from the perspective that we’d like to design interventions that work forever,” said Ms. Milkman. But she also noted that there are lots of opportunities to try again. Gym visits don’t just pick up at New Year’s but at the start of each week, each semester, after holidays, and even after birthdays (though not 21st birthdays). The key is getting one of the fresh starts to stick.
“从我们希望设计永久有效的干预这个角度来说，这种结果令人失望，”米尔克曼说。不过她也指出，有很多重新尝试的机会。去健身房的人次增加不仅出现在新年伊始，也出现在每周和每学期开始的时候，以及节假日甚至生日（但并不包括达到合法饮酒年龄的那个生日）过后。关键是让其中一种坚持下去。

Heather Royer, an economist at the University of California, Santa Barbara, thinks she has hit on a way. In partnership with a Fortune 500 company, she and her research partners ran an experiment that combined two interventions: One to get people to start going to the gym, and another to keep them there. For four weeks, the company paid its employees to work out, $10 per visit up to three times a week. After those four weeks, there were no more payments, but some workers were offered a “commitment contract”: They could set aside their own money that would be released to them only if they worked out over the next two months; otherwise, it would be given away to charity.
加州大学圣巴巴拉分校(University of California, Santa Barbara)的经济学者希瑟·罗耶(Heather Royer)认为自己发现了一种方法。她和研究伙伴与一家财富500强(Fortune 500)公司合作，进行了一项实验，将两种干预结合起来：一种是让人们开始去健身，另一种是让他们坚持下去。在四周的时间里，这家公司出钱让员工去锻炼，每次奖励10美元，一周最多三次。四周过后，公司不再发钱，但部分员工签署了一份“承诺合约”：他们自己留出一部分钱，接下来两个月如果坚持锻炼，就会还给他们；如果没能坚持锻炼，这些钱将被捐给慈善机构。

Even though those commitment contracts ended three months after the start of the study, the effects on workout frequency persisted for years: Three years after the study, the workers who had been offered the contracts remained 20 percent more likely to work out than those who had not been offered any incentives. By inducing a habit with cash payments, and then reinforcing that habit with self-funded payments, the researchers were able to permanently change workout habits for at least some people.
尽管这类承诺合约在研究开始三个月后就到期了，但它们对锻炼频率的影响却持续了多年：研究项目过去三年后，当初签署合约的员工健身的几率，依然比那些什么激励都没得到的人高20%。通过用现金奖励的方式培养一种习惯，然后再用自己出钱的方式来巩固习惯，研究人员永久性地改变了至少部分人的锻炼习惯。

The researchers at Wharton also found demand for continuing self-control devices: After study completion, 61 percent of subjects said they’d be willing to pay for gym-only audio books as a measure to help themselves work out.
沃顿商学院的研究人员还发现，需要有持续性的自我控制策略：研究结束后，61%的实验对象表示愿意出钱购买只能在健身房听的有声读物，以此作为促进他们锻炼的手段。

So why don’t gyms offer these kinds of devices to drive members to work out more?
那么，健身房为何不提供这类措施，促使会员多锻炼呢？

“They have a little bit of a conflict of interest,” says Richard Thaler, a behavioral economist at the University of Chicago. The fact that lots of people join gyms and rarely go to them isn’t great for our national waistline, but it’s pretty good for people who own gyms. “If they succeeded in getting people to go to the gym three times a week instead of three times a month, they wouldn’t be able to have as many members.”
“这里有一点利益冲突，”芝加哥大学(University of Chicago)行为经济学家理查德·塞勒(Richard Thaler)说。很多人办了健身卡却很少去这个事实，对国民腰围不利，但对健身房老板却很有利。“如果他们成功地让人们一周去三次健身房，而不是一个月三次，可能就没法接纳那么多会员了。”

The more promising avenue may be employers. Ms. Royer hopes to later demonstrate not just that commitment contracts work to get employees to the gym, but also that they save employers enough through improved health to be worth paying for.
更靠谱的途径可能在于雇主。罗耶随后希望证明，承诺合约不仅可以颇有成效地促使雇员去健身房，还可以通过改善员工的健康，为雇主省下足够多的钱，从而让雇主的投入物有所值。

For now, you can use a service like Stickk to set up your own commitment contract: Promise to go to the gym, and set aside money that will be given to charity if you don’t. For extra incentive, you can even use an anti-charity: If you don’t work out, your money will be given to a cause you hate. That’s more likely to keep you working out through beach season than simply paying up front for a gym membership.
目前，你可以用Stickk等服务制定自己的承诺合约：承诺去健身房，并留出一些钱，如果不去便捐给慈善机构。如果需要额外的激励，你甚至可以利用自己不喜欢的机构：如果不锻炼，你的钱就会捐给你讨厌的某项事业。和预先花钱办健身房会员卡相比，这种做法更有可能让你在整个去沙滩游玩的季节坚持锻炼。