Abstract
When public opinion gets polarized, the population’s beliefs can experience two different changes: they can become more extreme in their contents or they can be held with greater confidence. These two possibilities point to two different understandings of the rupture that characterizes political polarization: extremism and radicalism. In this article, I show that from the close examination of the best available evidence regarding how we get polarized, it follows that the pernicious type of political polarization has more to do with radicalism than with extremism. Reinforcing the confidence in the core beliefs of the group we identify with makes our beliefs immune to the reasons coming from the other political side. Finally, I also suggest that the rise of political polarization is not necessarily the result of an irrational process.