Belief polarization (BP) is widely seen to threaten havoc on our shared political lives. It is often assumed that BP is the product of epistemically irrational behaviors at the individual level. After distinguishing between BP as it occurs in intra-group and inter-group settings, this paper argues that neither process necessarily reflects individual epistemic irrationality. It is true that these processes can work in tandem to produce so-called “echo chambers.” But while echo chambers are often problematic from the point of view of collective rationality, it doesn't follow that individuals are doing anything wrong, epistemically speaking, in seeking them out. In non-ideal socio-epistemic contexts, echo chamber construction might provide one's best defense against systematic misinformation and deception.

Studies of the American public demonstrate that partisans often diverge not only on questions of opinion but also on matters of fact. However, little is known about partisan divergence in factual beliefs among the government officials who make real policy decisions, or how it compares to belief polarization among the public. This letter describes the first systematic comparison of factual belief polarization between the public and government officials, which we conducted using a paired survey approach. The results indicate that political elites are consistently more accurately informed than the public across a wide range of politically contentious facts. However, this increase in accuracy does not translate into reduced factual belief polarization. These findings demonstrate that a more informed political elite does not necessarily mitigate partisan factual disagreement in policy making.