Data from: Reciprocity and the tragedies of maintaining and providing the commons

Social cooperation often requires collectively beneficial but individually costly restraint to maintain a public good, or it needs costly generosity to create one. Status quo effects predict that maintaining a public good is easier than providing a new one. Here, we show experimentally and with simulations that even under identical incentives, low levels of cooperation (the ‘tragedy of the commons’) are systematically more likely in maintenance than provision. Across three series of experiments, we find that strong and weak positive reciprocity, known to be fundamental tendencies underpinning human cooperation, are substantially diminished under maintenance compared with provision. As we show in a fourth experiment, the opposite holds for negative reciprocity (‘punishment’). Our findings suggest that incentives to avoid the ‘tragedy of the commons’ need to contend with dilemma-specific reciprocity.

社会合作往往需要个体付出代价、但能惠及整体的克制行为，以维系公共物品；或是需要投入高昂成本的慷慨举措，来创建公共物品。现状效应（status quo effects）指出，维系公共物品比创建全新公共物品更为容易。本研究通过实验与模拟分析证实，即便激励条件完全一致，公共物品维系场景下合作水平低下（即“公地悲剧（tragedy of the commons）”）的系统性发生概率，显著高于公共物品创建场景。在三组系列实验中，我们发现，被视为支撑人类合作核心倾向的强正互惠与弱正互惠，在维系场景下相较于创建场景出现了显著衰减。正如第四项实验所证实的，负互惠（即“惩罚”）的表现则恰好相反。本研究结果表明，规避“公地悲剧”的激励机制，需针对不同困境特有的互惠模式进行适配。