Simulation Models of the Collective Consequences of Bounded Rationality in Opinion Formation in Networks: Cases of Market Concentration and Vaccination Opinion Polarization

Human opinions emerge from a complex interplay of psychological, social, and environmental factors. This dissertation explores the collective consequences of bounded rationality in opinion formation, particularly market concentration and opinion polarization, and examines how these outcomes arise from the social interactions of heterogeneous individuals from a theoretical perspective. These micro-macro interactions are intricate, not only due to the multitude of heterogeneous individual agents involved, each of which is a complex system in itself, but also because they occur through various types of networks. The simulation results reveal that, in the consumer market, we see that even perfectly homogeneous product markets can produce market concentration due to consumers’ limited attention and complex social processes. In the public health domain, people’s decision-making process for vaccination is subject to a combination of heuristic strategies, cognitive biases, and sociocultural influences, which may result in social polarization. These findings help us understand a number of related social phenomena.