Opinion Fluctuations and Disagreement in Social Networks

被引:302
作者
Acemoglu, Daron [1 ]
Como, Giacomo [2 ]
Fagnani, Fabio [3 ]
Ozdaglar, Asuman [4 ,5 ]
机构
[1] MIT, Dept Econ, Cambridge, MA 02139 USA
[2] Lund Univ, Dept Automat Control, S-22100 Lund, Sweden
[3] Politecn Torino, Dipartimento Sci Matemat, I-10129 Turin, Italy
[4] MIT, Lab Informat & Decis Syst, Cambridge, MA 02139 USA
[5] MIT, Dept Elect Engn, Cambridge, MA 02139 USA
基金
瑞典研究理事会;
关键词
opinion dynamics; multiagent systems; social networks; persistent disagreement; opinion fluctuations; social influence; CONSENSUS; DYNAMICS; AGENTS; FAMILY; MODEL;
D O I
10.1287/moor.1120.0570
中图分类号
C93 [管理学]; O22 [运筹学];
学科分类号
070105 ; 12 ; 1201 ; 1202 ; 120202 ;
摘要
We study a tractable opinion dynamics model that generates long-run disagreements and persistent opinion fluctuations. Our model involves an inhomogeneous stochastic gossip process of continuous opinion dynamics in a society consisting of two types of agents: (1) regular agents who update their beliefs according to information that they receive from their social neighbors and (2) stubborn agents who never update their opinions and might represent leaders, political parties, or media sources attempting to influence the beliefs in the rest of the society. When the society contains stubborn agents with different opinions, the belief dynamics never lead to a consensus (among the regular agents). Instead, beliefs in the society fail to converge almost surely, the belief profile keeps on fluctuating in an ergodic fashion, and it converges in law to a nondegenerate random vector. The structure of the graph describing the social network and the location of the stubborn agents within it shape the opinion dynamics. The expected belief vector is proved to evolve according to an ordinary differential equation coinciding with the Kolmogorov backward equation of a continuous-time Markov chain on the graph with absorbing states corresponding to the stubborn agents, and hence to converge to a harmonic vector, with every regular agent's value being the weighted average of its neighbors' values, and boundary conditions corresponding to the stubborn agents' beliefs. Expected cross products of the agents' beliefs allow for a similar characterization in terms of coupled Markov chains on the graph describing the social network. We prove that, in large-scale societies, which are highly fluid, meaning that the product of the mixing time of the Markov chain on the graph describing the social network and the relative size of the linkages to stubborn agents vanishes as the population size grows large, a condition of homogeneous influence emerges, whereby the stationary beliefs' marginal distributions of most of the regular agents have approximately equal first and second moments.
引用
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页码:1 / 27
页数:27
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