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PLoS Comput Biol. 2016 Jan 25;12(1):e1004709. doi: 10.1371/journal.pcbi.1004709. eCollection 2016 Jan.

Social Norms of Cooperation in Small-Scale Societies.

Author information

1
INESC-ID and Instituto Superior Técnico, Universidade de Lisboa, IST-Tagusparque, Porto Salvo, Portugal.
2
ATP-Group, Lisboa, Portugal.
3
Centro de Biologia Molecular e Ambiental, Universidade do Minho, Braga, Portugal.
4
Departamento de Matemática e Aplicações, Universidade do Minho, Braga, Portugal.

Abstract

Indirect reciprocity, besides providing a convenient framework to address the evolution of moral systems, offers a simple and plausible explanation for the prevalence of cooperation among unrelated individuals. By helping someone, an individual may increase her/his reputation, which may change the pre-disposition of others to help her/him in the future. This, however, depends on what is reckoned as a good or a bad action, i.e., on the adopted social norm responsible for raising or damaging a reputation. In particular, it remains an open question which social norms are able to foster cooperation in small-scale societies, while enduring the wide plethora of stochastic affects inherent to finite populations. Here we address this problem by studying the stochastic dynamics of cooperation under distinct social norms, showing that the leading norms capable of promoting cooperation depend on the community size. However, only a single norm systematically leads to the highest cooperative standards in small communities. That simple norm dictates that only whoever cooperates with good individuals, and defects against bad ones, deserves a good reputation, a pattern that proves robust to errors, mutations and variations in the intensity of selection.

PMID:
26808261
PMCID:
PMC4726523
DOI:
10.1371/journal.pcbi.1004709
[Indexed for MEDLINE]
Free PMC Article

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