550 research outputs found
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
Theories of the evolution of cooperative behaviour: A critical survey plus some new results
Gratuitous cooperation (in favour of non-relatives and without repeated interaction) eludes traditional evolutionary explanations. In this paper we survey the various theories of cooperative behaviour, and we describe our own effort to integrate these theories into a self-contained framework. Our main conclusions are as follows. First: altruistic punishment, conformism and gratuitous cooperation co-evolve, and group selection is a necessary ingredient for the co-evolution to take place. Second: people do not cooperate by mistake, as most theories imply; on the contrary, people knowingly sacrifice themselves for others. Third: in cooperative dilemmas conformism is an expression of preference, not a learning rule. Fourth, group-mutations (e.g., the rare emergence of a charismatic leader that brings order to the group) are necessary to sustain cooperation in the long run.Cooperation; altruism; altruistic punishment; conformism; group-selection
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
Cooperation and the Emergence of Role Differentiation in the Dynamics of Social Networks
By means of extensive computer simulations, the authors consider the
entangled coevolution of actions and social structure in a new version of a
spatial Prisoner's Dilemma model that naturally gives way to a process of
social differentiation. Diverse social roles emerge from the dynamics of the
system: leaders are individuals getting a large payoff who are imitated by a
considerable fraction of the population, conformists are unsatisfied
cooperative agents that keep cooperating, and exploiters are defectors with a
payoff larger than the average one obtained by cooperators. The dynamics
generate a social network that can have the topology of a small world network.
The network has a strong hierarchical structure in which the leaders play an
essential role in sustaining a highly cooperative stable regime. But
disruptions affecting leaders produce social crises described as dynamical
cascades that propagate through the network.Comment: (15 pages, 7 figures
Theories of the evolution of cooperative behaviour: A critical survey plus some new results
Gratuitous cooperation (in favour of non-relatives and without repeated interaction) eludes traditional evolutionary explanations. In this paper we survey the various theories of cooperative behaviour, and we describe our own effort to integrate these theories into a self-contained framework. Our main conclusions are as follows. First: altruistic punishment, conformism and gratuitous cooperation co-evolve, and group selection is a necessary ingredient for the co-evolution to take place. Second: people do not cooperate by mistake, as most theories imply; on the contrary, people knowingly sacrifice themselves for others. Third: in cooperative dilemmas conformism is an expression of preference, not a learning rule. Fourth, group-mutations (e.g., the rare emergence of a charismatic leader that brings order to the group) are necessary to sustain cooperation in the long run
Theories of the evolution of cooperative behaviour: A critical survey plus some new results
Gratuitous cooperation (in favour of non-relatives and without repeated interaction) eludes traditional evolutionary explanations. In this paper we survey the various theories of cooperative behaviour, and we describe our own effort to integrate these theories into a self-contained framework. Our main conclusions are as follows. First: altruistic punishment, conformism and gratuitous cooperation co-evolve, and group selection is a necessary ingredient for the co-evolution to take place. Second: people do not cooperate by mistake, as most theories imply; on the contrary, people knowingly sacrifice themselves for others. Third: in cooperative dilemmas conformism is an expression of preference, not a learning rule. Fourth, group-mutations (e.g., the rare emergence of a charismatic leader that brings order to the group) are necessary to sustain cooperation in the long run
Cooperative Prisoners and Aggressive Chickens: Evolution of Strategies and Preferences in 2x2 Games
By means of simulations I investigate a two-speed dynamic on strategies and preferences in the prisoners' dilemma and in the chicken game. Players learn strategies according to their preferences while evolution leads to a change in preference composition. With complete information cooperation in the prisoners' dilemma is often achieved, with 'reciprocal' preferences. In the chicken game a symmetric correlated strategy profile is played that is as efficient as the symmetric equilibrium. Among preferences only pure 'hawkish' preferences and 'selfish' preferences survive. With incomplete information, the symmetric equilibrium of the material payoff game is played. All types of preferences are present in the population in the medium run.
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