Identity Drives Polarization: Advancing the Hegselmann-Krause Model by Identity Groups

In this article we describe an Agent-Based Model that extends the Hegselmann-Krause model of opinion dynamics to study the role of social identity in opinion polarization. In our model, an agent's social identity is a function of two things-the agent's opinion in relation to those of the other agents, and the observer's sensitivity to the tightness of clustering. We implement this by first selecting a subset of the agent population that are deemed to have close neighbors, and then using Louvain community detection to find identity groups. At every time step, agents only consider the opinions of other agents within their identity group that also fall within their Hegselmann-Krause opinion boundary, epsilon. We show that our dynamic implementation of social identity systematically modulates the relationship between average e and polarization.