Range of interaction in an opinion evolution model of ideological self-positioning: Contagion, hesitance and polarization

• A new model for the study of the ideological self-positioning was developed.
• Our results were compared with real data from opinion polls in some countries.
• The presence of undecided agents is crucial to reproduce data from polls.

The evolution of public opinion using tools and concepts borrowed from Statistical Physics is an emerging area within the field of Sociophysics. In the present paper, a Statistical Physics model was developed to study the evolution of the ideological self-positioning of an ensemble of agents. The model consists of an array of LL components, each one of which represents the ideology of an agent. The proposed mechanism is based on the “voter model”, in which one agent can adopt the opinion of another one if the difference of their opinions lies within a certain range. The existence of “undecided” agents (i.e. agents with no definite opinion) was implemented in the model. The possibility of radicalization of an agent’s opinion upon interaction with another one was also implemented. The results of our simulations are compared to statistical data taken from the Latinobarómetro databank for the cases of Argentina, Chile, Brazil and Uruguay in the last decade. Among other results, the effect of taking into account the undecided agents is the formation of a single peak at the middle of the ideological spectrum (which corresponds to a centrist ideological position), in agreement with the real cases studied.