Fixation and polarization in a three-species opinion dynamics model

Motivated by the dynamics of cultural change and diversity, we generalize the three-species constrained voter model on a complete graph introduced in J. Phys. A, 37 (2004) 8479. In this opinion dynamics model, a population of size N is composed of leftists and rightists that interact with centrists: a leftist and centrist can both become leftists with rate (1+q)/2 or centrists with rate (1−q)/2 (and similarly for rightists and centrists), where q denotes the bias towards extremism (q > 0) or centrism (q  0, but there is always a finite probability to reach a consensus; the opposite happens when q < 0. Our findings are corroborated by stochastic simulations.