1,786 research outputs found
Coevolutionary games - a mini review
Prevalence of cooperation within groups of selfish individuals is puzzling in
that it contradicts with the basic premise of natural selection. Favoring
players with higher fitness, the latter is key for understanding the challenges
faced by cooperators when competing with defectors. Evolutionary game theory
provides a competent theoretical framework for addressing the subtleties of
cooperation in such situations, which are known as social dilemmas. Recent
advances point towards the fact that the evolution of strategies alone may be
insufficient to fully exploit the benefits offered by cooperative behavior.
Indeed, while spatial structure and heterogeneity, for example, have been
recognized as potent promoters of cooperation, coevolutionary rules can extend
the potentials of such entities further, and even more importantly, lead to the
understanding of their emergence. The introduction of coevolutionary rules to
evolutionary games implies, that besides the evolution of strategies, another
property may simultaneously be subject to evolution as well. Coevolutionary
rules may affect the interaction network, the reproduction capability of
players, their reputation, mobility or age. Here we review recent works on
evolutionary games incorporating coevolutionary rules, as well as give a
didactic description of potential pitfalls and misconceptions associated with
the subject. In addition, we briefly outline directions for future research
that we feel are promising, thereby particularly focusing on dynamical effects
of coevolutionary rules on the evolution of cooperation, which are still widely
open to research and thus hold promise of exciting new discoveries.Comment: 24 two-column pages, 10 figures; accepted for publication in
BioSystem
Evolution of interactions and cooperation in the spatial prisoner's dilemma game
We study the evolution of cooperation in the spatial prisoner's dilemma game
where players are allowed to establish new interactions with others. By
employing a simple coevolutionary rule entailing only two crucial parameters,
we find that different selection criteria for the new interaction partners as
well as their number vitally affect the outcome of the game. The resolution of
the social dilemma is most probable if the selection favors more successful
players and if their maximally attainable number is restricted. While the
preferential selection of the best players promotes cooperation irrespective of
game parametrization, the optimal number of new interactions depends somewhat
on the temptation to defect. Our findings reveal that the "making of new
friends" may be an important activity for the successful evolution of
cooperation, but also that partners must be selected carefully and their number
limited.Comment: 14 pages, 6 figures; accepted for publication in PLoS ON
Optimal interdependence between networks for the evolution of cooperation
Recent research has identified interactions between networks as crucial for the outcome of evolutionary
games taking place on them. While the consensus is that interdependence does promote cooperation by
means of organizational complexity and enhanced reciprocity that is out of reach on isolated networks, we
here address the question just how much interdependence there should be. Intuitively, one might assume
the more the better. However, we show that in fact only an intermediate density of sufficiently strong
interactions between networks warrants an optimal resolution of social dilemmas. This is due to an intricate
interplay between the heterogeneity that causes an asymmetric strategy flow because of the additional links
between the networks, and the independent formation of cooperative patterns on each individual network.
Presented results are robust to variations of the strategy updating rule, the topology of interdependent
networks, and the governing social dilemma, thus suggesting a high degree of universality
Collective behavior and evolutionary games - An introduction
This is an introduction to the special issue titled "Collective behavior and
evolutionary games" that is in the making at Chaos, Solitons & Fractals. The
term collective behavior covers many different phenomena in nature and society.
From bird flocks and fish swarms to social movements and herding effects, it is
the lack of a central planner that makes the spontaneous emergence of sometimes
beautifully ordered and seemingly meticulously designed behavior all the more
sensational and intriguing. The goal of the special issue is to attract
submissions that identify unifying principles that describe the essential
aspects of collective behavior, and which thus allow for a better
interpretation and foster the understanding of the complexity arising in such
systems. As the title of the special issue suggests, the later may come from
the realm of evolutionary games, but this is certainly not a necessity, neither
for this special issue, and certainly not in general. Interdisciplinary work on
all aspects of collective behavior, regardless of background and motivation,
and including synchronization and human cognition, is very welcome.Comment: 6 two-column pages, 1 figure; accepted for publication in Chaos,
Solitons & Fractals [the special issue is available at
http://www.sciencedirect.com/science/journal/09600779/56
Conformity enhances network reciprocity in evolutionary social dilemmas
The pursuit of highest payoffs in evolutionary social dilemmas is risky and
sometimes inferior to conformity. Choosing the most common strategy within the
interaction range is safer because it ensures that the payoff of an individual
will not be much lower than average. Herding instincts and crowd behavior in
humans and social animals also compel to conformity on their own right.
Motivated by these facts, we here study the impact of conformity on the
evolution of cooperation in social dilemmas. We show that an appropriate
fraction of conformists within the population introduces an effective surface
tension around cooperative clusters and ensures smooth interfaces between
different strategy domains. Payoff-driven players brake the symmetry in favor
of cooperation and enable an expansion of clusters past the boundaries imposed
by traditional network reciprocity. This mechanism works even under the most
testing conditions, and it is robust against variations of the interaction
network as long as degree-normalized payoffs are applied. Conformity may thus
be beneficial for the resolution of social dilemmas.Comment: 8 two-column pages, 5 figures; accepted for publication in Journal of
the Royal Society Interfac
Coevolution of Cooperation and Partner Rewiring Range in Spatial Social Networks
In recent years, there has been growing interest in the study of
coevolutionary games on networks. Despite much progress, little attention has
been paid to spatially embedded networks, where the underlying geographic
distance, rather than the graph distance, is an important and relevant aspect
of the partner rewiring process. It thus remains largely unclear how individual
partner rewiring range preference, local vs. global, emerges and affects
cooperation. Here we explicitly address this issue using a coevolutionary model
of cooperation and partner rewiring range preference in spatially embedded
social networks. In contrast to local rewiring, global rewiring has no distance
restriction but incurs a one-time cost upon establishing any long range link.
We find that under a wide range of model parameters, global partner switching
preference can coevolve with cooperation. Moreover, the resulting partner
network is highly degree-heterogeneous with small average shortest path length
while maintaining high clustering, thereby possessing small-world properties.
We also discover an optimum availability of reputation information for the
emergence of global cooperators, who form distant partnerships at a cost to
themselves. From the coevolutionary perspective, our work may help explain the
ubiquity of small-world topologies arising alongside cooperation in the real
world
Different reactions to adverse neighborhoods in games of cooperation
In social dilemmas, cooperation among randomly interacting individuals is
often difficult to achieve. The situation changes if interactions take place in
a network where the network structure jointly evolves with the behavioral
strategies of the interacting individuals. In particular, cooperation can be
stabilized if individuals tend to cut interaction links when facing adverse
neighborhoods. Here we consider two different types of reaction to adverse
neighborhoods, and all possible mixtures between these reactions. When faced
with a gloomy outlook, players can either choose to cut and rewire some of
their links to other individuals, or they can migrate to another location and
establish new links in the new local neighborhood. We find that in general
local rewiring is more favorable for the evolution of cooperation than
emigration from adverse neighborhoods. Rewiring helps to maintain the diversity
in the degree distribution of players and favors the spontaneous emergence of
cooperative clusters. Both properties are known to favor the evolution of
cooperation on networks. Interestingly, a mixture of migration and rewiring is
even more favorable for the evolution of cooperation than rewiring on its own.
While most models only consider a single type of reaction to adverse
neighborhoods, the coexistence of several such reactions may actually be an
optimal setting for the evolution of cooperation.Comment: 12 pages, 5 figures; accepted for publication in PLoS ON
The Impact of Coevolution and Abstention on the Emergence of Cooperation
This paper explores the Coevolutionary Optional Prisoner's Dilemma (COPD)
game, which is a simple model to coevolve game strategy and link weights of
agents playing the Optional Prisoner's Dilemma game. We consider a population
of agents placed in a lattice grid with boundary conditions. A number of Monte
Carlo simulations are performed to investigate the impacts of the COPD game on
the emergence of cooperation. Results show that the coevolutionary rules enable
cooperators to survive and even dominate, with the presence of abstainers in
the population playing a key role in the protection of cooperators against
exploitation from defectors. We observe that in adverse conditions such as when
the initial population of abstainers is too scarce/abundant, or when the
temptation to defect is very high, cooperation has no chance of emerging.
However, when the simple coevolutionary rules are applied, cooperators
flourish.Comment: To appear at Studies in Computational Intelligence (SCI), Springer,
201
Leaders should not be conformists in evolutionary social dilemmas
The most common assumption in evolutionary game theory is that players should
adopt a strategy that warrants the highest payoff. However, recent studies
indicate that the spatial selection for cooperation is enhanced if an
appropriate fraction of the population chooses the most common rather than the
most profitable strategy within the interaction range. Such conformity might be
due to herding instincts or crowd behavior in humans and social animals. In a
heterogeneous population where individuals differ in their degree, collective
influence, or other traits, an unanswered question remains who should conform.
Selecting conformists randomly is the simplest choice, but it is neither a
realistic nor the optimal one. We show that, regardless of the source of
heterogeneity and game parametrization, socially the most favorable outcomes
emerge if the masses conform. On the other hand, forcing leaders to conform
significantly hinders the constructive interplay between heterogeneity and
coordination, leading to evolutionary outcomes that are worse still than if
conformists were chosen randomly. We conclude that leaders must be able to
create a following for network reciprocity to be optimally augmented by
conformity. In the opposite case, when leaders are castrated and made to
follow, the failure of coordination impairs the evolution of cooperation.Comment: 7 two-column pages, 4 figures; accepted for publication in Scientific
Reports [related work available at arXiv:1412.4113
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