Original
Indirect reciprocity with dual private assessment
Abstract
People often cooperate out of concern for their reputation. The corresponding theory of indirect reciprocity predicts that such cooperation can only evolve if people's opinions of each other are sufficiently correlated. This correlation, however, can be difficult to achieve when individuals form their opinions independently from one another, as in private assessment models. In that case, errors can generate disagreements that propagate throughout a population. Here, we identify a simple mechanism that mitigates this problem. Most prior work assumes that observers revise only the reputations of donors-the individuals who choose whether to cooperate or defect. We instead allow observers to also revise the reputations of recipients-the individuals affected by the donors' choices. Using analytical calculations and simulations, we show that such dual reputation updates help synchronize opinions and facilitate cooperation. To demonstrate this approach, we focus on a particularly simple rule, which we call Recipient Image Scoring (RIS). Under RIS, recipients are assessed as good whenever donors choose to cooperate with them. We show that this rule for judging recipients effectively complements the classical leading-eight rules for judging donors. Our results establish dual assessment as a simple mechanism for cooperation that relies only on directly observable information.
中文
双重私人评价下的间接互惠
摘要
人们常常出于对自身声誉的关心而合作。相应的间接互惠理论预测，这种合作只有在人们彼此的看法充分相关时才能演化。然而，当个体像在私人评价模型中那样独立形成各自看法时，这种相关性可能难以实现。在这种情况下，错误会产生分歧，并在整个群体中传播。在此，我们识别出一种缓解该问题的简单机制。多数既有研究假设观察者只更新捐赠者——即选择合作或不合作的人——的声誉。我们则允许观察者也更新接受者——即受捐赠者选择影响的人——的声誉。通过解析计算和模拟，我们表明这种双重声誉更新有助于同步看法并促进合作。为展示这一方法，我们聚焦于一条特别简单的规则，我们称之为接受者形象评分（Recipient Image Scoring, RIS）。在RIS下，只要捐赠者选择与其合作，接受者就被评价为好的。我们表明，这条用于评判接受者的规则有效补充了用于评判捐赠者的经典“前八”（leading-eight）规则。我们的结果确立了双重评价作为一种仅依赖可直接观察信息的简单合作机制。
关键词
间接互惠、声誉、私人评价、双重评价、合作演化、接受者形象评分、社会规范、演化博弈论