title: Behaviorial evolution: does similarity breed cooperation?
abstract: Reciprocity, whether direct or indirect, is thought to be the key to establishing cooperation among non-relatives. But Riolo et al. have presented a model in which cooperation is instead based on similarity: agents donate only when their partner's 'tag' lies within a 'tolerance' range around their own. Here we point out that their model requires individuals with identical tags to cooperate with each other, and show that cooperation tends to collapse when individuals bearing identical tags are given the option of not donating. We therefore question their mechanism for maintaining cooperation without reciprocity.
authors.affiliation: Evolution and Behaviour Research Group, School of Biological Sciences, Henry Wellcome Building for Neuroecology, University of Newcastle upon Tyne, Newcastle upon Tyne NE2 4HH, UK. gilbert.roberts@ncl.ac.uk
authors.forename: Gilbert
authors.initials: G
authors.lastname: Roberts
authors.forename: Thomas N
authors.initials: TN
authors.lastname: Sherratt
mesh_terms: D000533:Altruism; D000818:Animals; D015982:Bias; D005075:Biological Evolution; D003299:Cooperative Behavior; D005716:Game Theory; D006801:Humans; D008954:Models, Biological; D011157:Population Dynamics; D013045:Species Specificity