Recent Research Has Shown That the Divide Between Democrats and Republicans

Recent research has shown that the divide between Democrats and Republicans in the United States has become such a major part of people's identities that they are often loyal to their party not because they agree with its platform or policies but because they don't like the people they believe to be in the other party. Additional research shows that this is problematic because many people are wrong about who is actually in the other party. For example, Republicans believe a third of Democrats are agnostics or atheists, while in fact, only 9% of Democrats are. On the other hand, Democrats believe almost half of Republicans make over $250,000 a year, while in fact, only 2% of Republicans do (https://fivethirtyeight.com/features/democrats-are-wrong-about-republicans-republicans-are-wrong-about-democrats/). What cultural factor creates these misperceptions, and what imperative of intercultural communication asserts that Democrats and Republicans should learn how to communicate with each other?