25,072 research outputs found
Conformity-Driven Agents Support Ordered Phases in the Spatial Public Goods Game
We investigate the spatial Public Goods Game in the presence of
fitness-driven and conformity-driven agents. This framework usually considers
only the former type of agents, i.e., agents that tend to imitate the strategy
of their fittest neighbors. However, whenever we study social systems, the
evolution of a population might be affected also by social behaviors as
conformism, stubbornness, altruism, and selfishness. Although the term
evolution can assume different meanings depending on the considered domain,
here it corresponds to the set of processes that lead a system towards an
equilibrium or a steady-state. We map fitness to the agents' payoff so that
richer agents are those most imitated by fitness-driven agents, while
conformity-driven agents tend to imitate the strategy assumed by the majority
of their neighbors. Numerical simulations aim to identify the nature of the
transition, on varying the amount of the relative density of conformity-driven
agents in the population, and to study the nature of related equilibria.
Remarkably, we find that conformism generally fosters ordered cooperative
phases and may also lead to bistable behaviors.Comment: 13 pages, 5 figure
Agent-based Social Psychology: from Neurocognitive Processes to Social Data
Moral Foundation Theory states that groups of different observers may rely on
partially dissimilar sets of moral foundations, thereby reaching different
moral valuations. The use of functional imaging techniques has revealed a
spectrum of cognitive styles with respect to the differential handling of novel
or corroborating information that is correlated to political affiliation. Here
we characterize the collective behavior of an agent-based model whose inter
individual interactions due to information exchange in the form of opinions are
in qualitative agreement with experimental neuroscience data. The main
conclusion derived connects the existence of diversity in the cognitive
strategies and statistics of the sets of moral foundations and suggests that
this connection arises from interactions between agents. Thus a simple
interacting agent model, whose interactions are in accord with empirical data
on conformity and learning processes, presents statistical signatures
consistent with moral judgment patterns of conservatives and liberals as
obtained by survey studies of social psychology.Comment: 11 pages, 4 figures, 2 C codes, to appear in Advances in Complex
System
Homogeneous symmetrical threshold model with nonconformity: independence vs. anticonformity
We study two variants of the modified Watts threshold model with a noise
(with nonconformity, in the terminology of social psychology) on a complete
graph. Within the first version, a noise is introduced via so-called
independence, whereas in the second version anticonformity plays the role of a
noise, which destroys the order. The modified Watts threshold model, studied
here, is homogeneous and posses an up-down symmetry, which makes it similar to
other binary opinion models with a single-flip dynamics, such as the
majority-vote and the q-voter models. Because within the majority-vote model
with independence only continuous phase transitions are observed, whereas
within the q-voter model with independence also discontinuous phase transitions
are possible, we ask the question about the factor, which could be responsible
for discontinuity of the order parameter. We investigate the model via the
mean-field approach, which gives the exact result in the case of a complete
graph, as well as via Monte Carlo simulations. Additionally, we provide a
heuristic reasoning, which explains observed phenomena. We show that indeed, if
the threshold r = 0.5, which corresponds to the majority-vote model, an
order-disorder transition is continuous. Moreover, results obtained for both
versions of the model (one with independence and the second one with
anticonformity) give the same results, only rescaled by the factor of 2.
However, for r > 0.5 the jump of the order parameter and the hysteresis is
observed for the model with independence, and both versions of the model give
qualitatively different results.Comment: 12 pages, 4 figures, accepted to Complexit
Social Conformity Despite Individual Preferences for Distinctiveness
We demonstrate that individual behaviors directed at the attainment of
distinctiveness can in fact produce complete social conformity. We thus offer
an unexpected generative mechanism for this central social phenomenon.
Specifically, we establish that agents who have fixed needs to be distinct and
adapt their positions to achieve distinctiveness goals, can nevertheless
self-organize to a limiting state of absolute conformity. This seemingly
paradoxical result is deduced formally from a small number of natural
assumptions, and is then explored at length computationally. Interesting
departures from this conformity equilibrium are also possible, including
divergence in positions. The effect of extremist minorities on these dynamics
is discussed. A simple extension is then introduced, which allows the model to
generate and maintain social diversity, including multimodal distinctiveness
distributions. The paper contributes formal definitions, analytical deductions,
and counterintuitive findings to the literature on individual distinctiveness
and social conformity.Comment: 11 pages, 6 figures, appendi
The Role of Noise in the Spatial Public Goods Game
In this work we aim to analyze the role of noise in the spatial Public Goods
Game, one of the most famous games in Evolutionary Game Theory. The dynamics of
this game is affected by a number of parameters and processes, namely the
topology of interactions among the agents, the synergy factor, and the strategy
revision phase. The latter is a process that allows agents to change their
strategy. Notably, rational agents tend to imitate richer neighbors, in order
to increase the probability to maximize their payoff. By implementing a
stochastic revision process, it is possible to control the level of noise in
the system, so that even irrational updates may occur. In particular, in this
work we study the effect of noise on the macroscopic behavior of a finite
structured population playing the Public Goods Game. We consider both the case
of a homogeneous population, where the noise in the system is controlled by
tuning a parameter representing the level of stochasticity in the strategy
revision phase, and a heterogeneous population composed of a variable
proportion of rational and irrational agents. In both cases numerical
investigations show that the Public Goods Game has a very rich behavior which
strongly depends on the amount of noise in the system and on the value of the
synergy factor. To conclude, our study sheds a new light on the relations
between the microscopic dynamics of the Public Goods Game and its macroscopic
behavior, strengthening the link between the field of Evolutionary Game Theory
and statistical physics.Comment: 14 pages, 3 figure
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