Rational populists: the social consequences of shared narratives

We study a simple opinion dynamic model where a number of influencers have the possibility of conditioning it by supporting one of two alternative narratives. Influencers choose the narrative to support in order to optimize their return. They can therefore choose to support a narrative that is socially dysfunctional with which they need not agree with, insofar as the environmental conditions make it convenient. We show in particular under what conditions the dynamic leads to social polarization, that is, eventual takeover of one narrative over the other. The critical factors in this regard are the persuasion strength of the narratives and the number of influencers who are active. Stronger persuasion and a larger number of influencers both favor the takeover of one narrative over the other. In particular, simulation results suggest that even small changes in persuasion strength may cause major changes in the social dynamic and sudden regime shifts. We discuss the policy implications of these results, with an eye to current trends in online media in reinforcement of persuasion strength, e.g. by deploying artificial bots that reverberate one narrative at the expense of the others.