Opinion dynamics under the influence of radical groups, charismatic leaders, and other constant signals: A simple unifying model

By a simple extension of the bounded confidence model, it is possible tomodel the influence of a radical group, or a charismatic leader on theopinion dynamics of `normal' agents that update their opinions underboth, the influence of their normal peers, and the additional influenceof the radical group or a charismatic leader. From a more abstract pointof view, we model the influence of a signal, that is constant, may havedifferent intensities, and is `heard' only by agents with opinions, that arenot too far away. For such a dynamic a Constant Signal Theorem is proven.In the model we get a lot of surprising effects. For instance,the more intensive signal may have less effect; more radicals may lead to less radicalization of normal agents. The model is an extremely simple conceptual model. Undersome assumptions the whole parameter space can be analyzed. The modelinspires new possible explanations, new perspectives for empirical studies,and new ideas for prevention or intervention policies.