Linkage Based on the Kandori Norm Successfully Sustains Cooperation in Social Dilemmas

Since social dilemmas among n-persons are often embedded in other types of social exchanges, the exclusion of defectors in social dilemmas from other exchanges functions as a costless selective incentive. Recently, such “linkage” has been considered as a promising solution to resolve the social dilemma problem. However, previous research showed that cooperation sustained by linkage is fragile when subjective perception errors exist. The purpose of this study is to find linkage strategies that are robust against subjective perception errors. Based on the strategies presented in previous studies on indirect reciprocity, we devised several linkage strategies and examined their evolutionary stability by agent-based simulation. The simulation results showed that the linkage strategy based on kandori was evolutionarily stable even when perception errors existed. Our study provides substantial support for the argument that linkage is a plausible solution to the social dilemma problem.

Selective Incentive Mechanisms in the Union Voluntary Assistance and their Implications for Equity in the Brazilian Federalism

O artigo analisa o efeito dos mecanismos de incentivo seletivos adotados nas transferências da assistência voluntária da União, entre 2004 e 2014, tendo em vista os propósitos de maior equidade entre os entes federados na distribuição dos recursos. O estudo combina estatística descritiva e análise de conteúdo das resoluções do FNDE que regulamentaram a assistência técnica e financeira da União aos entes federados subnacionais, tomando como referência as abordagens neoinstitucionalistas no campo do federalismo. Os resultados apontam para os limites dos mecanismos utilizados diante da profunda desigualdade territorial que marca a federação brasileira.

Tactical Innovation, Democratic Governance, and Mixed Motives: Popular Movement Resilience in Peru and Ecuador

Urban popular movements that organize illegal land invasion communities present an intriguing puzzle. When most invasion organizations acquire land titles, their participation levels plummet and their agendas stagnate; yet some neighborhoods achieve land titles, sustain high participation, and acquire other services, such as piped-in water. Why do these organizations achieve movement resilience? The more typical trajectory of movement collapse is explained by the disappearance of the key selective incentive, property security. Some organizations, however, evade this “security trap” through mixed motives: their basic material agenda is supplemented by a nonmaterial and often altruistic agenda, which sustains participation in the face of reduced selective incentives. Examining three neighborhood case studies in Lima and Quito, this article argues that a new, “innovator” type of invasion organization is more likely to exhibit sustained participation and movement resilience due to tactical innovation, democratic governance, and mixed motives.

Cheating can stabilize cooperation in mutualisms

Mutualisms present a challenge for evolutionary theory. How is cooperation maintained in the face of selection for selfishness and cheating? Both theory and data suggest that partner choice, where one species preferentially directs aid to the more cooperative members of the other species, is central to cooperation in many mutualisms. However, the theory has only so far considered the evolutionary effects of partner choice on one of the species in a mutualism in isolation. Here, we investigate the co-evolution of cooperation and choice in a choosy host and its symbiont. Our model reveals that even though choice and cooperation may be initially selected, it will often be unstable. This is because choice reduces variation in the symbiont and, therefore, tends to remove the selective incentive for its own maintenance (a scenario paralleled in the lek paradox in female choice and policing in within-species cooperation). However, we also show that when variability is reintroduced into symbionts each generation, in the form of less cooperative individuals, choice is maintained. This suggests that the presence of cheaters and cheater species in many mutualisms is central to the maintenance of partner choice and, paradoxically, cooperation itself.