The Japanese Society for Artificial Intelligence

Echo chamber, the state in which agents are split into groups sharing the same opinions, is a well-known phenomenon in social networks. Opinion dynamics models have been proposed to explain how the phenomenon occurs through agents revising their opinions. However, social network users also exchange beliefs supporting their opinions. This has not been taken into account. In this paper, we extend an existing opinion dynamics model by allowing agents to exchange and update both beliefs and opinions. The process of updating beliefs is described based on the classical belief revision theory. Beliefs and opinions can influence each other guided by values that agents share. We compare opinion propagation with respect to belief influence. Simulation results show that echo chambers are reinforced by interactions between opinions and beliefs.