79,866 research outputs found
Network regularity and the influence of asycnhronism on the evolution of cooperation
In a population of interacting agents, the update dynamics
defines the temporal relation between the moments at which agents update
the strategies they use when they interact with other agents. The
update dynamics is said to be synchronous if this process occurs simultaneously
for all the agents and asynchronous if this is not the case. On
the other hand, the network of contacts defines who may interact with
whom. In this paper, we investigate the features of the network of contacts
that play an important role in the influence of the update dynamics
on the evolution of cooperative behaviors in a population of agents. First
we show that asynchronous dynamics is detrimental to cooperation only
when 1) the network of contacts is highly regular and 2) there is no noise
in the strategy update process. We then show that, among the different
features of the network of contacts, network regularity plays indeed a
major role in the influence of the update dynamics, in combination with
the temporal scale at which clusters of cooperator agents grow
Degree Variance and Emotional Strategies Catalyze Cooperation in Dynamic Signed Networks
We study the problem of the emergence of cooperation in dynamic signed
networks where agent strategies coevolve with relational signs and network
topology. Running simulations based on an agent-based model, we compare results
obtained in a regular lattice initialization with those obtained on a
comparable random network initialization. We show that the increased degree
heterogeneity at the outset enlarges the parametric conditions in which
cooperation survives in the long run. Furthermore, we show how the presence of
sign-dependent emotional strategies catalyze the evolution of cooperation with
both network topology initializations.Comment: 16 Pages, Proceeding of the European Conference on Modelling and
Simumatio
Cooperation in the snowdrift game on directed small-world networks under self-questioning and noisy conditions
Cooperation in the evolutionary snowdrift game with a self-questioning
updating mechanism is studied on annealed and quenched small-world networks
with directed couplings. Around the payoff parameter value , we find a
size-invariant symmetrical cooperation effect. While generally suppressing
cooperation for payoffs, rewired networks facilitated cooperative
behavior for . Fair amounts of noise were found to break the observed
symmetry and further weaken cooperation at relatively large values of .
However, in the absence of noise, the self-questioning mechanism recovers
symmetrical behavior and elevates altruism even under large-reward conditions.
Our results suggest that an updating mechanism of this type is necessary to
stabilize cooperation in a spatially structured environment which is otherwise
detrimental to cooperative behavior, especially at high cost-to-benefit ratios.
Additionally, we employ component and local stability analyses to better
understand the nature of the manifested dynamics.Comment: 7 pages, 6 figures, 1 tabl
Evolution of ethnocentrism on undirected and directed Barabási-Albert networks
Using Monte Carlo simulations, we study the evolution of contigent cooperation and ethnocentrism in the one-move game. Interactions and reproduction among computational agents are simulated on undirected and directed Barabási-\ud
Albert (BA) networks. We first replicate the Hammond-Axelrod model of in-group favoritism on a square lattice and then generalize this model on undirected and directed BA networks for both asexual and sexual reproduction cases. Our simulations demonstrate that irrespective of the mode of reproduction, ethnocentric strategy becomes common even though cooperation is individually costly and mechanisms such as reciprocity or conformity are absent. Moreover, our results indicate that the spread of favoritism toward similar others highly depends on the network topology and the associated heterogeneity of the studied population
Emotional Strategies as Catalysts for Cooperation in Signed Networks
The evolution of unconditional cooperation is one of the fundamental problems
in science. A new solution is proposed to solve this puzzle. We treat this
issue with an evolutionary model in which agents play the Prisoner's Dilemma on
signed networks. The topology is allowed to co-evolve with relational signs as
well as with agent strategies. We introduce a strategy that is conditional on
the emotional content embedded in network signs. We show that this strategy
acts as a catalyst and creates favorable conditions for the spread of
unconditional cooperation. In line with the literature, we found evidence that
the evolution of cooperation most likely occurs in networks with relatively
high chances of rewiring and with low likelihood of strategy adoption. While a
low likelihood of rewiring enhances cooperation, a very high likelihood seems
to limit its diffusion. Furthermore, unlike in non-signed networks, cooperation
becomes more prevalent in denser topologies.Comment: 24 pages, Accepted for publication in Advances in Complex System
How groups can foster consensus: The case of local cultures
A local culture denotes a commonly shared behaviour within a cluster of
firms. Similar to social norms or conventions, it is an emergent feature
resulting from the firms' interaction in an economic network. To model these
dynamics, we consider a distributed agent population, representing e.g. firms
or individuals. Further, we build on a continuous opinion dynamics model with
bounded confidence (), which assumes that two agents only interact if
differences in their behaviour are less than . Interaction results in
more similarity of behaviour, i.e. convergence towards a common mean. This
framework is extended by two major concepts: (i) The agent's in-group
consisting of acquainted interaction partners is explicitly taken into account.
This leads to an effective agent behaviour reflecting that agents try to
continue to interact with past partners and thus to keep sufficiently close to
them. (ii) The in-group network structure changes over time, as agents can form
new links to other agents with sufficiently close effective behaviour or delete
links to agents no longer close in behaviour. Thus, our model provides a
feedback mechanism between the agents' behaviour and their in-group structure.
Studying its consequences by means of agent-based computer simulations, we find
that for narrow-minded agents (low ) the additional feedback helps to
find consensus more often, whereas for open-minded agents (high )
this does not hold. This counterintuitive result is explained by simulations of
the network evolution
Automata-based adaptive behavior for economic modeling using game theory
In this paper, we deal with some specific domains of applications to game
theory. This is one of the major class of models in the new approaches of
modelling in the economic domain. For that, we use genetic automata which allow
to buid adaptive strategies for the players. We explain how the automata-based
formalism proposed - matrix representation of automata with multiplicities -
allows to define a semi-distance between the strategy behaviors. With that
tools, we are able to generate an automatic processus to compute emergent
systems of entities whose behaviors are represented by these genetic automata
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