364 research outputs found
Transitions between homophilic and heterophilic modes of cooperation
Cooperation is ubiquitous in biological and social systems. Previous studies
revealed that a preference toward similar appearance promotes cooperation, a
phenomenon called tag-mediated cooperation or communitarian cooperation. This
effect is enhanced when a spatial structure is incorporated, because space
allows agents sharing an identical tag to regroup to form locally cooperative
clusters. In spatially distributed settings, one can also consider migration of
organisms, which has a potential to further promote evolution of cooperation by
facilitating spatial clustering. However, it has not yet been considered in
spatial tag-mediated cooperation models. Here we show, using computer
simulations of a spatial model of evolutionary games with organismal migration,
that tag-based segregation and homophilic cooperation arise for a wide range of
parameters. In the meantime, our results also show another evolutionarily
stable outcome, where a high level of heterophilic cooperation is maintained in
spatially well-mixed patterns. We found that these two different forms of
tag-mediated cooperation appear alternately as the parameter for temptation to
defect is increased.Comment: 16 pages, 7 figure
Adaptive long-range migration promotes cooperation under tempting conditions
Migration is a fundamental trait in humans and animals. Recent studies
investigated the effect of migration on the evolution of cooperation, showing
that contingent migration favors cooperation in spatial structures. In those
studies, only local migration to immediate neighbors was considered, while
long-range migration has not been considered yet, partly because the long-range
migration has been generally regarded as harmful for cooperation as it would
bring the population to a well-mixed state that favors defection. Here, we
studied the effects of adaptive long-range migration on the evolution of
cooperation through agent-based simulations of a spatial Prisoner's Dilemma
game where individuals can jump to a farther site if they are surrounded by
more defectors. Our results show that adaptive long-range migration strongly
promotes cooperation, especially under conditions where the temptation to
defect is considerably high. These findings demonstrate the significance of
adaptive long-range migration for the evolution of cooperation.Comment: 7 pages, 9 figure
日本におけるインフルエンザ定点観測データの解析
Open House, ISM in Tachikawa, 2013.6.14統計数理研究所オープンハウス(立川)、H25.6.14ポスター発
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