62 research outputs found
Social Aggregation as a Cooperative Game
A new approach for the description of phenomena of social aggregation is
suggested. On the basis of psychological concepts (as for instance social norms
and cultural coordinates), we deduce a general mechanism for the social
aggregation in which different clusters of individuals can merge according to
the cooperation among the agents. In their turn, the agents can cooperate or
defect according to the clusters distribution inside the system. The fitness of
an individual increases with the size of its cluster, but decreases with the
work the individual had to do in order to join it. In order to test the
reliability of such new approach, we introduce a couple of simple toy models
with the features illustrated above. We see, from this preliminary study, how
the cooperation is the most convenient strategy only in presence of very large
clusters, while on the other hand it is not necessary to have one hundred
percent of cooperators for reaching a totally ordered configuration with only
one megacluster filling the whole system.Comment: 18 pages, 10 figure
Consensus Emerging from the Bottom-up: the Role of Cognitive Variables in Opinion Dynamics
The study of opinions e.g., their formation and change, and their effects
on our society by means of theoretical and numerical models has been one of
the main goals of sociophysics until now, but it is one of the defining topics
addressed by social psychology and complexity science. Despite the flourishing
of different models and theories, several key questions still remain
unanswered. The aim of this paper is to provide a cognitively grounded
computational model of opinions in which they are described as mental
representations and defined in terms of distinctive mental features. We also
define how these representations change dynamically through different
processes, describing the interplay between mental and social dynamics of
opinions. We present two versions of the model, one with discrete opinions
(voter model-like), and one with continuous ones (Deffuant-like). By means of
numerical simulations, we compare the behaviour of our cognitive model with the
classical sociophysical models, and we identify interesting differences in the
dynamics of consensus for each of the models considered.Comment: 14 pages, 8 figure
Partner selection supports reputation-based cooperation in a Public Goods Game
In dyadic models of indirect reciprocity, the receivers' history of giving
has a significant impact on the donor's decision. When the interaction involves
more than two agents things become more complicated, and in large groups
cooperation can hardly emerge. In this work we use a Public Goods Game to
investigate whether publicly available reputation scores may support the
evolution of cooperation and whether this is affected by the kind of network
structure adopted. Moreover, if agents interact on a bipartite graph with
partner selection cooperation can thrive in large groups and in a small amount
of time.Comment: 6 pages, 10 figures. In press for Springer E
Ordering phase transition in the one-dimensional Axelrod model
We study the one-dimensional behavior of a cellular automaton aimed at the
description of the formation and evolution of cultural domains. The model
exhibits a non-equilibrium transition between a phase with all the system
sharing the same culture and a disordered phase of coexisting regions with
different cultural features. Depending on the initial distribution of the
disorder the transition occurs at different values of the model parameters.
This phenomenology is qualitatively captured by a mean-field approach, which
maps the dynamics into a multi-species reaction-diffusion problem.Comment: 11 pages, 10 figures, accepted for publication in EPJ
Modelling opinion misperception and the emergence of silence in online social system
In the last decades an increasing deal of research has investigated the
phenomenon of opinion misperception in human communities and, more recently, in
social media. Opinion misperception is the wrong evaluation by community's
members of the real distribution of opinions or beliefs about a given topic. In
this work we explore the mechanisms giving rise to opinion misperception in
social media groups, which are larger than physical ones and have peculiar
topological features. By means of numerical simulations, we suggest that the
structure of connections of such communities plays indeed a role in distorting
the perception of the agents about others' beliefs, but it is essentially an
indirect effect. Moreover, we show that the main ingredient that generates the
misperception is a spiral of silence induced by few, well connected and
charismatic agents, which rapidly drives the majority of individuals to stay
silent without disclosing their true belief, leading minoritarian opinions to
appear more widespread throughout the community.Comment: 13 pages, 5 figures, 1 table. To be submitted soo
Bluffing as a Rational Strategy in a Simple Poker-Like Game Model
We present a simple adaptive learning model of a poker-like game, by means of which we show how a bluffing strategy emerges very naturally and can also be rational and evolutionarily stable. Despite their very simple learning algorithms, agents learn to bluff, and the most bluffing player is usually the winner
Evolution of gossip-based indirect reciprocity on a bipartite network
Cooperation can be supported by indirect reciprocity via reputation. Thanks to gossip, reputations are built and circulated and humans can identify defectors and ostracise them. However, the evolutionary stability of gossip is allegedly undermined by the fact that it is more error-prone that direct observation, whereas ostracism could be ineffective if the partner selection mechanism is not robust. The aim of this work is to investigate the conditions under which the combination of gossip and ostracism might support cooperation in groups of different sizes. We are also interested in exploring the extent to which errors in transmission might undermine the reliability of gossip as a mechanism for identifying defectors. Our results show that a large quantity of gossip is necessary to support cooperation, and that group structure can mitigate the effects of errors in transmission.We want to thank the editor and two anonymous reviewers for their comments and suggestions. D.V. received support from H2020 FETPROACT-GSS CIMPLEX Grant No. 641191
- …