Milinski Manfred, Semmann Dirk, Krambeck Hans-Jürgen, Marotzke Jochem
Department of Evolutionary Ecology, Max Planck Institute of Limnology, 24306 Plön, Germany.
Proc Natl Acad Sci U S A. 2006 Mar 14;103(11):3994-8. doi: 10.1073/pnas.0504902103. Epub 2006 Mar 1.
Maintaining the Earth's climate within habitable boundaries is probably the greatest "public goods game" played by humans. However, with >6 billion "players" taking part, the game seems to rule out individual altruistic behavior. Thus, climate protection is a problem of sustaining a public resource that everybody is free to overuse, a "tragedy of the commons" problem that emerges in many social dilemmas. We perform a previously undescribed type of public goods experiment with human subjects contributing to a public pool. In contrast to the standard protocol, here the common pool is not divided among the participants; instead, it is promised that the pool will be invested to encourage people to reduce their fossil fuel use. Our extensive experiments demonstrate that players can behave altruistically to maintain the Earth's climate given the right set of circumstances. We find a nonzero basic level of altruistic behavior, which is enhanced if the players are provided with expert information describing the state of knowledge in climate research. Furthermore, personal investments in climate protection increase substantially if players can invest publicly, thus gaining social reputation. This increase occurs because subjects reward other subjects' contributions to sustaining the climate, thus reinforcing their altruism. Therefore, altruism may convert to net personal benefit and to relaxing the dilemma if the gain in reputation is large enough. Our finding that people reward contributions to sustaining the climate of others is a surprising result. There are obvious ways these unexpected findings can be applied on a large scale.
将地球气候维持在宜居范围内可能是人类参与的最重大的“公共物品博弈”。然而，有60多亿“参与者”参与其中，这场博弈似乎排除了个人的利他行为。因此，气候保护是一个维持公共资源的问题，每个人都可以随意过度使用这一资源，这是一个在许多社会困境中都会出现的“公地悲剧”问题。我们对人类受试者进行了一种前所未有的公共物品实验，让他们为一个公共资源池做出贡献。与标准方案不同的是，这里的公共资源池不会在参与者之间分配；相反，承诺会对该资源池进行投资，以鼓励人们减少化石燃料的使用。我们广泛的实验表明，在合适的环境下，参与者可以表现出利他行为来维持地球气候。我们发现了一个非零的利他行为基本水平，如果向参与者提供描述气候研究知识状态的专家信息，这个水平会得到提高。此外，如果参与者能够公开投资，从而获得社会声誉，那么他们在气候保护方面的个人投资会大幅增加。这种增加的出现是因为受试者会奖励其他受试者为维持气候所做出的贡献，从而强化了他们的利他主义。因此，如果声誉的提升足够大，利他主义可能会转化为个人的净收益，并缓解困境。我们发现人们会奖励他人为维持气候所做出的贡献，这是一个令人惊讶的结果。这些意外发现有明显的大规模应用方式。
