22,804 research outputs found
Kinetic models of collective decision-making in the presence of equality bias
We introduce and discuss kinetic models describing the influence of the
competence in the evolution of decisions in a multi-agent system. The original
exchange mechanism, which is based on the human tendency to compromise and
change opinion through self-thinking, is here modified to include the role of
the agents' competence. In particular, we take into account the agents'
tendency to behave in the same way as if they were as good, or as bad, as their
partner: the so-called equality bias. This occurred in a situation where a wide
gap separated the competence of group members. We discuss the main properties
of the kinetic models and numerically investigate some examples of collective
decision under the influence of the equality bias. The results confirm that the
equality bias leads the group to suboptimal decisions
Acquaintance role for decision making and exchanges in social networks
We model a social network by a random graph whose nodes represent agents and
links between two of them stand for a reciprocal interaction; each agent is
also associated to a binary variable which represents a dichotomic opinion or
attribute. We consider both the case of pair-wise (p=2) and multiple (p>2)
interactions among agents and we study the behavior of the resulting system by
means of the energy-entropy scheme, typical of statistical mechanics methods.
We show, analytically and numerically, that the connectivity of the social
network plays a non-trivial role: while for pair-wise interactions (p=2) the
connectivity weights linearly, when interactions involve contemporary a number
of agents larger than two (p>2), its weight gets more and more important. As a
result, when p is large, a full consensus within the system, can be reached at
relatively small critical couplings with respect to the p=2 case usually
analyzed, or, otherwise stated, relatively small coupling strengths among
agents are sufficient to orient most of the system.Comment: 7 pages, 1 figur
Price dynamics in financial markets: a kinetic approach
The use of kinetic modelling based on partial differential equations for the
dynamics of stock price formation in financial markets is briefly reviewed. The
importance of behavioral aspects in market booms and crashes and the role of
agents' heterogeneity in emerging power laws for price distributions is
emphasized and discussed
Mass Media and Polarisation Processes in the Bounded Confidence Model of Opinion Dynamics
This paper presents a social simulation in which we add an additional layer of mass media communication to the social network \'bounded confidence\' model of Deffuant et al (2000). A population of agents on a lattice with continuous opinions and bounded confidence adjust their opinions on the basis of binary social network interactions between neighbours or communication with a fixed opinion. There are two mechanisms for interaction. \'Social interaction\' occurs between neighbours on a lattice and \'mass communication,\' adjusts opinions based on an agent interacting with a fixed opinion. Two new variables are added, polarisation: the degree to which two mass media opinions differ, and broadcast ratio: the number of social interactions for each mass media communication. Four dynamical regimes are observed, fragmented, double extreme convergence, a state of persistent opinion exchange leading to single extreme convergence and a disordered state. Double extreme convergence is found where agents are less willing to change opinion and mass media communications are common or where there is moderate willingness to change opinion and a high frequency of mass media communications. Single extreme convergence is found where there is moderate willingness to change opinion and a lower frequency of mass media communication. A period of persistent opinion exchange precedes single extreme convergence, it is characterized by the formation of two opposing groups of opinion separated by a gradient of opinion exchange. With even very low frequencies of mass media communications this results in a move to central opinions followed by a global drift to one extreme as one of the opposing groups of opinion dominates. A similar pattern of findings is observed for Neumann and Moore neighbourhoods.Opinion Dynamics, Mass Media, Polarisation, Extremists, Consensus
Adaptive network models of collective decision making in swarming systems
We consider a class of adaptive network models where links can only be
created or deleted between nodes in different states. These models provide an
approximate description of a set of systems where nodes represent agents moving
in physical or abstract space, the state of each node represents the agent's
heading direction, and links indicate mutual awareness. We show analytically
that the adaptive network description captures the phase transition to
collective motion in swarming systems and that the properties of this
transition are determined by the number of states (discrete heading directions)
that can be accessed by each agent.Comment: 8 pages, 5 figure
- …