Effects of Assortativity on Consensus Formation with Heterogeneous Agents

Abstract

AbstractUnderstanding the consensus formation and exploring its dynamics play an imperative role in studies of multi-agent systems. Researchers are aware of the significant effects of network topology on the dynamical process of consensus formation; therefore, much more attention has been devoted to analyzing these dependencies on the network topology. For example, it is known that the degree correlation between nodes in a network (assortativity) is a moderator factor which may have serious effects on the dynamics, and ignoring its effects in information diffusion studies may produce misleading results. Despite the widespread use of Barabasi’s scale-free networks and Erdos-Renyi networks of which degree correlation (assortativity) is neutral, numerous studies demonstrated that online social networks tend to show assortative mixing (positive degree correlation), while non-social networks show a disassortative mixing (negative degree correlation). First, we analyzed the variability in the assortativity coefficients of different groups of the same platform by using three different subreddits in Reddit. Our data analysis results showed that Reddit is disassortative, and assortativity coefficients of the aforementioned subreddits are computed as \(-0.0384\), \(-0.0588\) and \(-0.1107\), respectively. Motivated by the variability in the results even in the same platform, we decided to investigate the sensitivity of dynamics of consensus formation to the assortativity of the network. We concluded that the system is more likely to reach a consensus when the network is disassortatively mixed or neutral; however, the likelihood of the consensus significantly decreases when the network is assortatively mixed. Surprisingly, the time elapsed until all nodes fix their opinions is slightly lower when the network is neutral compared to either assortative or disassortative networks. These results are more pronounced when the thresholds of agents are more heterogeneously distributed.KeywordsConsensusDegree correlationMulti-agent systemReddit