CONICET | Buscador de Institutos y Recursos Humanos

Social dynamic opinion models have been widely studied to understand how interactionsamong individuals cause opinions to evolve. Most opinion models that utilizespin interaction models usually produce a consensus steady state in which only one opinionexists. Because in reality different opinions usually coexist, we focus on non-consensusopinion models in which above a certain threshold two opinions coexist in a stable relationship.We revisit and extend the non-consensus opinion (NCO) model introduced by Shaoet al. (Phys. Rev. Lett. 103:01870, 2009). The NCO model in random networks displays asecond order phase transition that belongs to regular mean field percolation and is characterizedby the appearance (above a certain threshold) of a large spanning cluster of the minorityopinion. We generalize the NCO model by adding a weight factor W to each individual?soriginal opinion when determining their future opinion (NCOW model). We find that asW increases the minority opinion holders tend to form stable clusters with a smaller initialminority fraction than in the NCO model. We also revisit another non-consensus opinionmodel based on the NCO model, the inflexible contrarian opinion (ICO) model (Li et al. inPhys. Rev. E 84:066101, 2011), which introduces inflexible contrarians to model the competitionbetween two opinions in a steady state. Inflexible contrarians are individuals that neverchange their original opinion but may influence the opinions of others. To place the inflexiblecontrarians in the ICO model we use two different strategies, random placement and one in which high-degree nodes are targeted. The inflexible contrarians effectively decrease thesize of the largest rival-opinion cluster in both strategies, but the effect is more pronouncedunder the targeted method. All of the above models have previously been explored in termsof a single network, but human communities are usually interconnected, not isolated. Becauseopinions propagate not only within single networks but also between networks, andbecause the rules of opinion formation within a network may differ from those between networks,we study here the opinion dynamics in coupled networks. Each network representsa social group or community and the interdependent links joining individuals from differentnetworks may be social ties that are unusually strong, e.g., married couples. We apply thenon-consensus opinion (NCO) rule on each individual network and the global majority ruleon interdependent pairs such that two interdependent agents with different opinions will,due to the influence of mass media, follow the majority opinion of the entire population.The opinion interactions within each network and the interdependent links across networksinterlace periodically until a steady state is reached. We find that the interdependent linkseffectively force the system from a second order phase transition, which is characteristic ofthe NCO model on a single network, to a hybrid phase transition, i.e., a mix of second-orderand abrupt jump-like transitions that ultimately becomes, as we increase the percentage ofinterdependent agents, a pure abrupt transition. We conclude that for the NCO model oncoupled networks, interactions through interdependent links could push the non-consensusopinion model to a consensus opinion model, which mimics the reality that increased masscommunication causes people to hold opinions that are increasingly similar. We also findthat the effect of interdependent links is more pronounced in interdependent scale free networksthan in interdependent Erd˝os Rényi networks.