Indirect reciprocity under incomplete observation

Mitsuhiro Nakamura, Naoki Masuda*


研究成果: Article査読

32 被引用数 (Scopus)


Indirect reciprocity, in which individuals help others with a good reputation but not those with a bad reputation, is a mechanism for cooperation in social dilemma situations when individuals do not repeatedly interact with the same partners. In a relatively large society where indirect reciprocity is relevant, individuals may not know each other's reputation even indirectly. Previous studies investigated the situations where individuals playing the game have to determine the action possibly without knowing others' reputations. Nevertheless, the possibility that observers of the game, who generate the reputation of the interacting players, assign reputations without complete information about them has been neglected. Because an individual acts as an interacting player and as an observer on different occasions if indirect reciprocity is endogenously sustained in a society, the incompleteness of information may affect either role. We examine the game of indirect reciprocity when the reputations of players are not necessarily known to observers and to interacting players. We find that the trustful discriminator, which cooperates with good and unknown players and defects against bad players, realizes cooperative societies under seven social norms. Among the seven social norms, three of the four suspicious norms under which cooperation (defection) to unknown players leads to a good (bad) reputation enable cooperation down to a relatively small observation probability. In contrast, the three trustful norms under which both cooperation and defection to unknown players lead to a good reputation are relatively efficient.

ジャーナルPLoS Computational Biology
出版ステータスPublished - 2011 7月

ASJC Scopus subject areas

  • 生態、進化、行動および分類学
  • モデリングとシミュレーション
  • 生態学
  • 分子生物学
  • 遺伝学
  • 細胞および分子神経科学
  • 計算理論と計算数学


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