Increasingly, we Americans occupy alternate universes, with very little common ground -- only battling perceptions of reality. A Pew study finds 81 of voters say .brIn this TEDx talk in Miami, Columbia University Professor Peter T. Coleman explains why politics in the US are more deadlocked and polarized today than they .brDescription.brLilliana Mason (University of Maryland) about polarization in American politics. Why are Democrat and Republican voters nowadays so devided? And what does .