为何有人愿为维基百科撰文？ Why does anyone bother contributing to Wikipedia?
A “Dear Economist” correspondent once asked me why people post clips of classic comedies on YouTube, or go to the trouble of writing online reviews, given that there seems to be nothing in it for them. A textbook economics model would say that people would not, in fact, post online reviews or contribute to YouTube. And my answer, in brief, was that they don’t. Far more people read books than write reviews of them, and far more watch YouTube videos than post them. As a broad defence of rational economic man, my answer wasn’t too bad; but as a way of understanding online volunteering, it was useless.
《亲爱的经济学家》的一位读者曾经写信问我，为什么看上去无利可图，还会有人在 YouTube上发布经典的搞笑视频，或者费心在网上撰写评论？按照教科书上的经济学模型，人们不应该在网上撰写评论或者在YouTube上发布视频。简 单地说，我的答案是他们并没有这样做。读书的人远远多于写评论的人，看视频的人也远远多于上传视频的人。作为对理性经济人的宽泛辩护，我的答案还算不错， 可惜对于理解在线志愿行为并没有帮助。
Economic theory is not entirely helpful, either. “Public good provision” is the economists’ name for installing a solar hot water system for the sake of the planet, or endowing a library, or contributing a paragraph to Wikipedia. The trouble is not that economics has no explanation for such contributions, but that it has too many. Perhaps people are pure altruists, motivated by the joy of others. Perhaps they enjoy the process of contributing, whether or not it actually produces something of value. Or perhaps they enjoy the good reputation that comes with being acknowledged as a Doer of Good Deeds.
经济学理论也不是很有帮助。为了保护地球安装太阳能热水器、资助图书馆或者在维基百科 中撰写一个段落之类的行为，经济学家称之为“公共物品提供”。问题不是经济学无法解释这种贡献行为，而是解释太多。可能有人是纯粹的利他主义者，自己的动 力就来源于他人的喜悦；可能他们享受的是贡献的过程，不论实际上是否创造了有价值的东西；可能他们只是喜欢“爱做好人好事”的好名声。
Until now, most of our understanding of the question has come from laboratory experiments. Given the importance of social context, these experiments may well be giving precise answers to the wrong question.
But a new study by two economists, Xiaoquan Zhang and Feng Zhu, has cast light on this problem. Zhang and Zhu look at the Chinese version of Wikipedia. Wikipedia keeps track of all the changes every registered user has ever made to the site, when the edits were made, and what they were. It also hosts user pages, where individual users can talk to each other and discuss the changes they’ve been making.
不过，经济学家张晓泉和朱峰最新的研究成果对解决这个问题有所启发。张晓泉和朱峰对维 基百科(Wikipedia)中文版进行了研究。维基百科会记录所有注册用户对网站所做的所有改动，包括编辑时间和编辑内容。网站上还设有用户页面，各个 用户之间可以互相交谈，对所做的修改展开讨论。
The Chinese government has a habit of blocking access to Wikipedia. Zhang and Zhu study a particular episode in October 2005 during which contributors who lived on the Chinese mainland couldn’t reach the site, but contributors from outside could.
The researchers painstakingly isolated 1,707 contributors who had access to Wikipedia during the block. In most cases, the evidence for this was that those contributors had made at least one change to the site while mainland users couldn’t get to it. They found that while the block was in force, contributions from these unblocked users plummeted by more than 40 per cent.
This finding contrasts with some economic models of public good provision, which say that the larger the group, the larger the free rider problem, because any individual contribution will be spread across a large number of people. (An imprecise analogy: you might bring expensive wine to a dinner party because at least you’ll get a glass. You wouldn’t bring it to a house party, where you’re unlikely to get a sip.)
这项研究与有关公共物品提供的一些经济学模型相冲突。模型认为，群体越大，免费搭车问 题就越严重，因为任何个人贡献都会由许多人分享。（一个不太恰当的比喻是，参加小宴席时你可能会带一瓶昂贵的红酒，因为至少自己能喝到一杯，但是参加大派 对时就不会，因为自己一口都喝不到。）
Chinese Wikipedia contributors, on the other hand, got coy when nobody was watching. When a large number of potential readers were cut off from the site, many writers who could have continued to contribute stopped bothering. The most sociable editors – those with active user pages – were the ones most likely to be discouraged.
So now I have a slightly better answer for my Dear Economist correspondent: people are posting those videos on YouTube because they’d really like you to watch them.