Multipolar opinion evolution in biased networks

Motivated by empirical research on bias and opinion formation, we introduce a novel multidimensional nonlinear opinion dynamical model where agents have individual biases, which are fixed, as well as opinions, which evolve. The dimensions are coupled through a normalization step, which is also the source of the nonlinearity, so that the state describes an agent's relative opinion of various options. This can capture, for example, an individual's relative trust in different media. In special cases including where biases are uniform across agents our model achieves consensus, but in general, behaviors are richer and capture multipolar opinion distributions. We examine general fixed points of the system, as well as special cases such as zero biases toward certain options or partitioned decision sets. Lastly, we demonstrate that our model exhibits polarization when biases are spatially correlated across the network, while, as empirical research suggests, a mixed community can mediate biases.