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An opinion dynamics model for the diffusion of innovations

MARTINS, Andre C. R.; PEREIRA, Carlos de B.; VICENTE, Renato
Fonte: ELSEVIER SCIENCE BV Publicador: ELSEVIER SCIENCE BV
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
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We study the dynamics of the adoption of new products by agents with continuous opinions and discrete actions (CODA). The model is such that the refusal in adopting a new idea or product is increasingly weighted by neighbor agents as evidence against the product. Under these rules, we study the distribution of adoption times and the final proportion of adopters in the population. We compare the cases where initial adopters are clustered to the case where they are randomly scattered around the social network and investigate small world effects on the final proportion of adopters. The model predicts a fat tailed distribution for late adopters which is verified by empirical data. (C) 2009 Elsevier B.V. All rights reserved.; Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP)[2008/00383-9]; Conselho Nacional de Desenvolvimento Cientifico a Tecnologico (CNPq)[550981/2007]

A dinâmica de opinião dos debates públicos em redes sociais complexas; The opinion dynamics of the public debates on complex social networks

Savoy, Daniel Prata
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 03/12/2012 Português
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67.258403%
Neste trabalho são estudados os efeitos, causados por variações na topologia de rede, no comportamento de quatro modelos de dinâmica de opinião: o Modelo Votante, o Modelo Confiança Limitada, o Modelo da Regra da Maioria e o Modelo CODA. Primeiramente estes modelos são utilizados em simulações que usam uma série de diversas redes sociais complexas, geradas para apresentar diferentes combinações de valores de certas propriedades chave, como aglomeração, conectividade, assortatividade e distâncias internas. Em seguida, são realizados experimentos que mostram como a topologia influencia os resultados na modelagem de cenários de debates públicos, onde duas opiniões rivais, A e B, disputam sob condições desiguais o consenso de uma população simulada.; This work studies the effects caused by variations in network topology in the behavior of four different models of opinion dynamics: the Voter Model, Bounded Confidence Model, the Majority Rule Model and the CODA Model. First, these models are used in simulations over a number of different complex social networks, generated to show sereval combinations of key properties such as clustering, connectivity, assortativity and path distances. Then, we perform experiments that show how the topology influences the results in modeling scenarios of public debates...

Dinâmica de opinião de Krause-Hegselmann em redes complexas; Opinion dynamics of Krause-Hegselmann on complex networks

Batista, João Luiz Bunoro
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 28/11/2012 Português
Relevância na Pesquisa
67.6348%
Fenômenos coletivos em redes sociais como a formação de linguagem ou cultura, crenças, emergência de consenso em relação a algum assunto, aquisição de conhecimento e aprendizagem, dentre outros, tem conduzido a um grande interesse no estudo de comportamentos cooperativos e fenômenos sociais, resultando numa grande variedade de dinâmicas de opinião. Nestes modelos, uma população de agentes interagentes carrega uma variável (ou um conjunto delas) numérica cujo valor representa uma opinião sobre um tópico, com interpretações distintas em cada contexto. Inspirados em conceitos de mecânica estatística e mecanismos sociais, estes estados evoluem governados por regras matemáticas que controlam a dinâmica de interação entre os agentes e a influência de fatores externos. Outro ingrediente importante na modelagem de sistemas reais é que a representação das interações entre agentes difere bastante de reticulados ou misturas homogêneas, sendo mais bem descritas por redes complexas. Neste trabalho, estudamos a dinâmica de opinião de Krause e Hegselmann. Neste modelo, agentes possuem opiniões que assumem valores contínuos e são atualizados de acordo com a vizinhança compatível, definida pelo princípio da confiança limitada. Após apresentar uma revisão da literatura...

Agent based models and opinion dynamics as Markov chains

Banisch, Sven; Lima, Ricardo; Araújo, Tanya
Fonte: ISEG - Departamento de Economia Publicador: ISEG - Departamento de Economia
Tipo: Outros
Publicado em //2012 Português
Relevância na Pesquisa
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This paper introduces a Markov chain approach that allows a rigorous analysis of agent based opinion dynamics as well as other related agent based models (ABM). By viewing the ABM dynamics as a micro description of the process, we show how the corresponding macro description is obtained by a projection construction. Then, well known conditions for lumpability make it possible to establish the cases where the macro model is stillMarkov. In this case we obtain a complete picture of the dynamics including the transient stage, the most interesting phase in applications. For such a purpose a crucial role is played by the type of probability distribution used to implement the stochastic part of the model which defines the updating rule and governs the dynamics. In addition, we show how restrictions in communication leading to the co–existence of different opinions follow from the emergence of new absorbing states. We describe our analysis in detail with some specific models of opinion dynamics. Generalizations concerning different opinion representations as well as opinion models with other interaction mechanisms are also discussed. We find that our method may be an attractive alternative to mean–field approaches and that this approach provides new perspectives on the modeling of opinion exchange dynamics...

Multi-Level Opinion Dynamics under Bounded Confidence

Kou, Gang; Zhao, Yiyi; Peng, Yi; Shi, Yong
Fonte: Public Library of Science Publicador: Public Library of Science
Tipo: Artigo de Revista Científica
Publicado em 19/09/2012 Português
Relevância na Pesquisa
47.53065%
Opinion dynamics focuses on the opinion evolution in a social community. Recently, some models of continuous opinion dynamics under bounded confidence were proposed by Deffuant and Krause, et al. In the literature, agents were generally assumed to have a homogeneous confidence level. This paper proposes an extended model for a group of agents with heterogeneous confidence levels. First, a social differentiation theory is introduced and a social group is divided into opinion subgroups with distinct confidence levels. Second, a multi-level heterogeneous opinion formation model is formulated under the framework of bounded confidence. Finally, computer simulations are conducted to study the collective opinion evolution, focusing on three key factors: the fractions of heterogeneous agents, the initial opinions, and the group size. The simulation results demonstrate that the number of final opinions depends on the fraction of close-minded agents when the group size and the initial opinions are fixed; the final opinions converge more easily when the initial opinions are closer; and the number of final opinions can be approximately modeled by a linear increasing function of the group size and the increasing rate is the fraction of close-minded agents.

Influence of Opinion Dynamics on the Evolution of Games

Gargiulo, Floriana; Ramasco, José J.
Fonte: Public Library of Science Publicador: Public Library of Science
Tipo: Artigo de Revista Científica
Publicado em 15/11/2012 Português
Relevância na Pesquisa
47.490947%
Under certain circumstances such as lack of information or bounded rationality, human players can take decisions on which strategy to choose in a game on the basis of simple opinions. These opinions can be modified after each round by observing own or others payoff results but can be also modified after interchanging impressions with other players. In this way, the update of the strategies can become a question that goes beyond simple evolutionary rules based on fitness and become a social issue. In this work, we explore this scenario by coupling a game with an opinion dynamics model. The opinion is represented by a continuous variable that corresponds to the certainty of the agents respect to which strategy is best. The opinions transform into actions by making the selection of an strategy a stochastic event with a probability regulated by the opinion. A certain regard for the previous round payoff is included but the main update rules of the opinion are given by a model inspired in social interchanges. We find that the fixed points of the dynamics of the coupled model are different from those of the evolutionary game or the opinion models alone. Furthermore, new features emerge such as the independence of the fraction of cooperators with respect to the topology of the social interaction network or the presence of a small fraction of extremist players.

Human opinion dynamics: An inspiration to solve complex optimization problems

Kaur, Rishemjit; Kumar, Ritesh; Bhondekar, Amol P.; Kapur, Pawan
Fonte: Nature Publishing Group Publicador: Nature Publishing Group
Tipo: Artigo de Revista Científica
Publicado em 21/10/2013 Português
Relevância na Pesquisa
47.50483%
Human interactions give rise to the formation of different kinds of opinions in a society. The study of formations and dynamics of opinions has been one of the most important areas in social physics. The opinion dynamics and associated social structure leads to decision making or so called opinion consensus. Opinion formation is a process of collective intelligence evolving from the integrative tendencies of social influence with the disintegrative effects of individualisation, and therefore could be exploited for developing search strategies. Here, we demonstrate that human opinion dynamics can be utilised to solve complex mathematical optimization problems. The results have been compared with a standard algorithm inspired from bird flocking behaviour and the comparison proves the efficacy of the proposed approach in general. Our investigation may open new avenues towards understanding the collective decision making.

Communication regimes in opinion dynamics: Changing the number of communicating agents

Urbig, Diemo; Lorenz, Jan
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 24/08/2007 Português
Relevância na Pesquisa
47.50483%
This article contributes in four ways to the research on time-discrete continuous opinion dynamics with compromising agents. First, communication regimes are introduced as an elementary concept of opinion dynamic models. Second, we develop a model that covers two major models of continuous opinion dynamics, i.e. the basic model of Deffuant and Weisbuch as well as the model of Krause and Hegselmann. To combine these models, which handle different numbers of communicating agents, we convert the convergence parameter of Deffuant and Weisbuch into a parameter called self-support. Third, we present simulation results that shed light on how the number of communicating agents but also how the self-support affect opinion dynamics. The fourth contribution is a theoretically driven criterion when to stop a simulation and how to extrapolate to infinite many steps.; Comment: 15 pages, 6 figures, In: Proceedings of the Second Conference of the European Social Simulation Association (ESSA), September 16-19, Valladolid, Spain, 2004 (ISBN 84-688-7964-9)

Opinion Dynamics and Price Formation: a Nonlinear Network Model

D'Errico, Marco; Muradoglu, Gulnur; Stefani, Silvana; Zambruno, Giovanni
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 01/08/2014 Português
Relevância na Pesquisa
47.50483%
Opinions and beliefs determine the evolution of social systems. This is of particular interest in finance, as the increasing complexity of financial systems is coupled with information overload. Opinion formation, therefore, is not always the result of optimal information processing. On the contrary, agents are boundedly rational and naturally tend to observe and imitate others in order to gain further insights. Hence, a certain degree of interaction, which can be envisioned as a network, occurs within the system. Opinions, the interaction network and prices in financial markets are then heavily intertwined and influence one another. We build on previous contributions on adaptive systems, where agents have hetereogenous beliefs, and introduce a dynamic confidence network that captures the interaction and shapes the opinion patterns. The analytical framework we adopt for modeling the interaction is rooted in the opinion dynamics problem. This will allow us to introduce a nonlinear model where the confidence network, opinion dynamics and price formation coevolve in time. A key aspect of the model is the classification of agents according to their topological role in the network, therefore showing that topology matters in determining how of opinions and prices will coevolve. We illustrate the dynamics via simulations...

A Distance Measure for the Analysis of Polar Opinion Dynamics in Social Networks

Amelkin, Victor; Singh, Ambuj; Bogdanov, Petko
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 16/10/2015 Português
Relevância na Pesquisa
47.60232%
Analysis of opinion dynamics in social networks plays an important role in today's life. For applications such as predicting users' political preference, it is particularly important to be able to analyze the dynamics of competing opinions. While observing the evolution of polar opinions of a social network's users over time, can we tell when the network "behaved" abnormally? Furthermore, can we predict how the opinions of the users will change in the future? Do opinions evolve according to existing network opinion dynamics models? To answer such questions, it is not sufficient to study individual user behavior, since opinions can spread far beyond users' egonets. We need a method to analyze opinion dynamics of all network users simultaneously and capture the effect of individuals' behavior on the global evolution pattern of the social network. In this work, we introduce Social Network Distance (SND) - a distance measure that quantifies the "cost" of evolution of one snapshot of a social network into another snapshot under various models of polar opinion propagation. SND has a rich semantics of a transportation problem, yet, is computable in time linear in the number of users, which makes SND applicable to the analysis of large-scale online social networks. In our experiments with synthetic and real-world Twitter data...

The role of inflexible minorities in the breaking of democratic opinion dynamics

Galam, Serge; Jacobs, Frans
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 02/03/2007 Português
Relevância na Pesquisa
47.60232%
We study the effect of inflexible agents on two state opinion dynamics. The model operates via repeated local updates of random grouping of agents. While floater agents do eventually flip their opinion to follow the local majority, inflexible agents keep their opinion always unchanged. It is a quenched individual opinion. In the bare model (no inflexibles), a separator at 50% drives the dynamics towards either one of two pure attractors, each associated with a full polarization along one of the opinions. The initial majority wins. The existence of inflexibles for only one of the two opinions is found to shift the separator at a lower value than 50% in favor of that side. Moreover it creates an incompressible minority around the inflexibles, one of the pure attractors becoming a mixed phase attractor. In addition above a threshold of 17% inflexibles make their side sure of winning whatever the initial conditions are. The inflexible minority wins. An equal presence of inflexibles on both sides restores the balanced dynamics with again a separator at 50% and now two mixed phase attractors on each side. Nevertheless, beyond 25% the dynamics is reversed with a unique attractor at a fifty-fifty stable equilibrium. But a very small advantage in inflexibles results in a decisive lowering of the separator at the advantage of the corresponding opinion. A few percent advantage does guarantee to become majority with one single attractor. The model is solved exhaustedly for groups of size 3.; Comment: 18 pages...

Opinion dynamics: inhomogeneous Boltzmann-type equations modelling opinion leadership and political segregation

Düring, Bertram; Wolfram, Marie-Therese
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 27/05/2015 Português
Relevância na Pesquisa
47.690767%
We propose and investigate different kinetic models for opinion formation, when the opinion formation process depends on an additional independent variable, e.g. a leadership or a spatial variable. More specifically, we consider:(i) opinion dynamics under the effect of opinion leadership, where each individual is characterised not only by its opinion, but also by another independent variable which quantifies leadership qualities; (ii) opinion dynamics modelling political segregation in the `The Big Sort', a phenomenon that US citizens increasingly prefer to live in neighbourhoods with politically like-minded individuals. Based on microscopic opinion consensus dynamics such models lead to inhomogeneous Boltzmann-type equations for the opinion distribution. We derive macroscopic Fokker-Planck-type equations in a quasi-invariant opinion limit and present results of numerical experiments.; Comment: 20 pages

Impact of Preference and Equivocators on Opinion Dynamics with Evolutionary Game Framework

Deng, Xinyang; Wang, Zhen; Liu, Qi; Deng, Yong; Shyr, Yu
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 28/07/2015 Português
Relevância na Pesquisa
47.5867%
Opinion dynamics, aiming to understand the evolution of collective behavior through various interaction mechanisms of opinions, represents one of the most challenges in natural and social science. To elucidate this issue clearly, binary opinion model becomes a useful framework, where agents can take an independent opinion. Inspired by the realistic observations, here we propose two basic interaction mechanisms of binary opinion model: one is the so-called BSO model in which players benefit from holding the same opinion; the other is called BDO model in which players benefit from taking different opinions. In terms of these two basic models, the synthetical effect of opinion preference and equivocators on the evolution of binary opinion is studied under the framework of evolutionary game theory (EGT), where the replicator equation (RE) is employed to mimick the evolution of opinions. By means of numerous simulations, we show the theoretical equilibrium states of binary opinion dynamics, and mathematically analyze the stability of each equilibrium state as well.; Comment: 15 pages, 6 figures

Opinion dynamics with disagreement and modulated information

Sîrbu, Alina; Loreto, Vittorio; Servedio, Vito D. P.; Tria, Francesca
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 01/12/2012 Português
Relevância na Pesquisa
47.50483%
Opinion dynamics concerns social processes through which populations or groups of individuals agree or disagree on specific issues. As such, modelling opinion dynamics represents an important research area that has been progressively acquiring relevance in many different domains. Existing approaches have mostly represented opinions through discrete binary or continuous variables by exploring a whole panoply of cases: e.g. independence, noise, external effects, multiple issues. In most of these cases the crucial ingredient is an attractive dynamics through which similar or similar enough agents get closer. Only rarely the possibility of explicit disagreement has been taken into account (i.e., the possibility for a repulsive interaction among individuals' opinions), and mostly for discrete or 1-dimensional opinions, through the introduction of additional model parameters. Here we introduce a new model of opinion formation, which focuses on the interplay between the possibility of explicit disagreement, modulated in a self-consistent way by the existing opinions' overlaps between the interacting individuals, and the effect of external information on the system. Opinions are modelled as a vector of continuous variables related to multiple possible choices for an issue. Information can be modulated to account for promoting multiple possible choices. Numerical results show that extreme information results in segregation and has a limited effect on the population...

Agent Based Models and Opinion Dynamics as Markov Chains

Banisch, Sven; Lima, Ricardo; Araújo, Tanya
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
47.659365%
This paper introduces a Markov chain approach that allows a rigorous analysis of agent based opinion dynamics as well as other related agent based models (ABM). By viewing the ABM dynamics as a micro description of the process, we show how the corresponding macro description is obtained by a projection construction. Then, well known conditions for lumpability make it possible to establish the cases where the macro model is still Markov. In this case we obtain a complete picture of the dynamics including the transient stage, the most interesting phase in applications. For such a purpose a crucial role is played by the type of probability distribution used to implement the stochastic part of the model which defines the updating rule and governs the dynamics. In addition, we show how restrictions in communication leading to the co-existence of different opinions follow from the emergence of new absorbing states. We describe our analysis in detail with some specific models of opinion dynamics. Generalizations concerning different opinion representations as well as opinion models with other interaction mechanisms are also discussed. We find that our method may be an attractive alternative to mean-field approaches and that this approach provides new perspectives on the modeling of opinion exchange dynamics...

Opinion Dynamics with Decaying Confidence: Application to Community Detection in Graphs

Morarescu, Irinel Constantin; Girard, Antoine
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
47.755117%
We study a class of discrete-time multi-agent systems modelling opinion dynamics with decaying confidence. We consider a network of agents where each agent has an opinion. At each time step, the agents exchange their opinion with their neighbors and update it by taking into account only the opinions that differ from their own less than some confidence bound. This confidence bound is decaying: an agent gives repetitively confidence only to its neighbors that approach sufficiently fast its opinion. Essentially, the agents try to reach an agreement with the constraint that it has to be approached no slower than a prescribed convergence rate. Under that constraint, global consensus may not be achieved and only local agreements may be reached. The agents reaching a local agreement form communities inside the network. In this paper, we analyze this opinion dynamics model: we show that communities correspond to asymptotically connected component of the network and give an algebraic characterization of communities in terms of eigenvalues of the matrix defining the collective dynamics. Finally, we apply our opinion dynamics model to address the problem of community detection in graphs. We propose a new formulation of the community detection problem based on eigenvalues of normalized Laplacian matrix of graphs and show that this problem can be solved using our opinion dynamics model. We consider three examples of networks...

The noisy Hegselmann-Krause model for opinion dynamics

Pineda, Miguel; Toral, Raul; Hernandez-Garcia, Emilio
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 11/09/2013 Português
Relevância na Pesquisa
47.62437%
In the model for continuous opinion dynamics introduced by Hegselmann and Krause, each individual moves to the average opinion of all individuals within an area of confidence. In this work we study the effects of noise in this system. With certain probability, individuals are given the opportunity to change spontaneously their opinion to another one selected randomly inside the opinion space with different rules. If the random jump does not occur, individuals interact through the Hegselmann-Krause's rule. We analyze two cases, one where individuals can carry out opinion random jumps inside the whole opinion space, and other where they are allowed to perform jumps just inside a small interval centered around the current opinion. We found that these opinion random jumps change the model behavior inducing interesting phenomena. Using pattern formation techniques, we obtain approximate analytical results for critical conditions of opinion cluster formation. Finally, we compare the results of this work with the noisy version of the Deffuant et al. model for continuous-opinion dynamics.

Scaling limits for continuous opinion dynamics systems

Como, Giacomo; Fagnani, Fabio
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
47.55734%
Scaling limits are analyzed for stochastic continuous opinion dynamics systems, also known as gossip models. In such models, agents update their vector-valued opinion to a convex combination (possibly agent- and opinion-dependent) of their current value and that of another observed agent. It is shown that, in the limit of large agent population size, the empirical opinion density concentrates, at an exponential probability rate, around the solution of a probability-measure-valued ordinary differential equation describing the system's mean-field dynamics. Properties of the associated initial value problem are studied. The asymptotic behavior of the solution is analyzed for bounded-confidence opinion dynamics, and in the presence of an heterogeneous influential environment.; Comment: Published at http://dx.doi.org/10.1214/10-AAP739 the Annals of Applied Probability (http://www.imstat.org/aap/) by the Institute of Mathematical Statistics (http://www.imstat.org)

Noisy continuous-opinion dynamics

Pineda, Miguel; Toral, Raúl; Hernández-García, Emilio
Fonte: Conselho Superior de Investigações Científicas Publicador: Conselho Superior de Investigações Científicas
Tipo: Pre-print Formato: 2373 bytes; 213769 bytes; text/plain; application/pdf
Português
Relevância na Pesquisa
57.5867%
18 pages, 7 figures, 1 appendix.-- Published in Journal of statistical mechanics (8): P08001 (2009).-- http://dx.doi.org/10.1088/1742-5468/2009/08/P08001; We study the Deffuant et al. model for continuous-opinion dynamics under the influence of noise. In the original version of this model, individuals meet in random pairwise encounters after which they compromise or not depending of a confidence parameter. Free will is introduced in the form of noisy perturbations: individuals are given the opportunity to change their opinion, with a given probability, to a randomly selected opinion inside the whole opinion space. We derive the master equation of this process. One of the main effects of noise is to induce an order-disorder transition. In the disordered state the opinion distribution tends to be uniform, while for the ordered state a set of well defined opinion groups are formed, although with some opinion spread inside them. Using a linear stability analysis we can derive approximate conditions for the transition between opinion groups and the disordered state. The master equation analysis is compared with direct Monte-Carlo simulations. We find that the master equation and the Monte-Carlo simulations do not always agree due to finite-size induced fluctuations that we analyze in some detail.; We acknowledge the financial support of project FIS2007-60327 from MICINN (Spain) and FEDER (EU) and project FP6-2005-NEST-Path-043268 (EU).; Peer reviewed

A spatially explicit agent-based model of opinion and reputation dynamics

Voorn, George van; Ligtenberg, Arend; Broeke, Guus ten
Fonte: Universidade Autônoma de Barcelona Publicador: Universidade Autônoma de Barcelona
Tipo: Conferência ou Objeto de Conferência Formato: application/pdf
Publicado em //2014 Português
Relevância na Pesquisa
57.55734%
Key in spatial planning are opinion dynamics (the exchange of opinions between agents and the consecutive updates in opinions by individual agents). A number of possibly relevant factors that are commonly excluded in well-known models of opinion dynamics are peer pressure, localized opinion formation through isolation, and the reputation of the agents involved. We present a model of agents with a fixed spatial location (e.g., a household) in a “village” who are capable of only local interactions with their neighbours. There exist nonlinear feedbacks between updates in opinion and reputation, which are described by smooth mathematical functions. Sensitivity analysis is used to quantify the contributions of different factors to the convergence of opinions within the “village”.