Opinion dynamics models describing the emergence of polarization phenomena

Some novel models of opinion dynamics are here formulated in terms of ordinary and of stochastic differential equations. The focus is on the possible emergence of polarization phenomena. Alongside attitudes and mechanisms related to individual-individual interactions, issues such as the influence of persuaders, acting perhaps on different time-scales, and uncertainty are taken into account. The existence of stationary solutions corresponding to polarized opinion distributions, together with their stability or instability properties, is established in correspondence to different parameter values.