The new analysis of data that dates back to the 1970s shows that disdain for an opposing party, or "out-party hate," for the first time has exceeded "warm" feelings American partisans have for their fellow party members, according to researchers at Northwestern University.
The authors of the study, published in the journal Science, determined that hatred of the opposing party is now "the dominant feeling in American politics" -- a phenomenon they have termed "political sectarianism."
Lead author Eli Finkel, a Northwestern professor of social psychology, said the political variety bears some resemblance to traditional religious sectarianism.
"The current state of political sectarianism produces prejudice, discrimination and cognitive distortion, undermining the ability of government to serve its core functions of representing the people and solving the nation's problems," Finkel said.
"Along the way, it makes people increasingly willing to support candidates who undermine democracy and to favor violence in support of their political goals."
Titled "Political Sectarianism in America," the study tapped experts in political science, psychology, sociology, economics, management and computational social science to examine three key elements of political sectarianism -- seeing the other side as different (othering), as dislikeable (aversion) and as immoral (moralization).
Researchers pored over survey data going back 50 years to calculate the difference between Americans' warm feelings toward their fellow partisans and cold feelings toward political counterparts. They found that although warm feelings have remained consistent, cold feelings have risen to a point that, for the first time, exceeds the former.
"Things have gotten much more severe in the past decade, and there is no sign we've hit bottom," said co-author James Druckman, a Northwestern University political science professor.
The key to overcoming rising cold feelings, he said, is pointed out in the study -- realizing that actual differences between partisans are far smaller than they're perceived to be.
President Donald Trump's rhetoric and constant derision of all Democrats as extremist left-wing socialists is a good example of a major influence on erroneous perceptions of a vast political divide.
"As much as the parties differ from one another, partisans perceive even greater differences, believing, for example, that the other party is ideologically extreme, engaged and hostile," Druckman said. "Correcting these types of misperceptions could partially vitiate sectarianism."
In another example, the study's authors say Republicans estimate that nearly a third of Democrats are members of the LGBT community, when in reality the true figure is 6%. Likewise, Democrats guess that nearly 40% of Republicans earn more than $250,000 per year, when just 2% actually do.
The study's authors lay some of the blame for the skewed political perceptions on the growth of partisan media -- which began during the 1980s when the Reagan administration terminated the Federal Communications Commission's "fairness doctrine," which called for news media to be fair and unbiased in their reporting.