Our strongest prejudice - partisan hostility

Jonathan Haidt points to the fascinating work by political scientists Shanto Iyengar and Sean Westwood, titled “Fear and Loathing Across Party Lines: New Evidence on Group Polarization.”, who found - in four studies designed to reveal prejudice based on race, gender, religion, or political party or ideology - that cross-partisan prejudice was the largest. For white participants who identified with a party, the cross-partisan effect was about 50 percent larger than the cross-race effect. Haidt points out that This is extremely bad news for America because:

...rising cross-partisan hostility means that Americans increasingly see the other side not just as wrong but as evil, as a threat to the very existence of the nation, according to Pew Research. Americans can expect rising polarization, nastiness, paralysis, and governmental dysfunction for a long time to come...This is extremely bad news for science and universities because universities are usually associated with the left...we can expect increasing hostility from Republican legislators toward universities and the things they desire, including research funding and freedom from federal and state control...This is a warning for the rest of the world because some of the trends that have driven America to this point are occurring in many other countries, including: rising education and individualism (which make people more ideological), rising immigration and ethnic diversity (which reduces social capital and trust), and stagnant economic growth (which puts people into a zero-sum mindset).

The situation is made worse by the "motive attribution asymmetry" that I have referenced in a previous post. Both sides of a political divide attribute their own aggressive behavior to love, but the opposite side's to hatred. Millions of Americans believe that their side is basically benevolent while the other side is evil and out to get them.