Figure 3

The emergence of political polarization. The top panels show an unpolarized (left panel) and a polarized (right panel) ideology distribution (synthetic/simulation data only). Democrats are represented by blue disks and Republicans by red disks. We use \(\Delta (\lambda )\) to denote the absolute value of the difference between the shifts in the mean ideologies. The bottom panels show the corresponding transition probabilities which define the ideology distribution according to Eqs. (6) and (7) with \(N=21\) states. We rescaled the probabilities in the right panel according to Eqs. (10) and (11) by setting \(\lambda =\lambda _{A}=\lambda _{B}=1.13\)