When Perception Trumps Reality: Republicans aren’t nearly as rich as Democrats estimate. Democrats aren’t nearly as gay or atheistic as Republicans estimate.

Democrats wildly over-estimate the percentage of Republicans who make over 250k a year (estimated: 44%; actual: 2%).  Republicans are almost as bad when it comes to predicting the percentage of Democrats who are LBG (estimated: 38%; actual: 6%) and atheist/agnostic (estimated: 36%; actual: 9%). Both groups were a little closer to the mark when asked to estimate details about their own parties, but the perception they are acting on is much more extreme than the data suggest. Caring more about partisan victories than about specific issues leads to extremism.

The academic article from which these statistics are drawn is “The Parties in Our Heads: Misperceptions about Party Composition and Their Consequences,” by Douglas J. Ahler and Gaurav Sood. (Journal of Politics 80.3).

If you’re not up to reading an academic article (and this one, being outside my field, was not easy for me to get through) here’s a paragraph from the discussion that helps explain why the researchers found these results significant:

Beyond beliefs about extremity, we suspect that perceptions about party composition affect people’s beliefs about the parties’ priorities. For instance, believing that a third of Democrats are atheist or agnostic, or that half of Republicans are evangelical, may lead one to believe that cultural issues like school prayer are far more important to the parties than they actually are. More generally, we suspect that people associate a narrow set of policy demands with each party-stereotypical group and think these groups have sway over the party’s agenda. This is liable to fuel more resentment and cynicism about the motivations of party elites

Here’s some analysis from a more informal, general-interest essay drawing on the above research. Caution — after Chrome loaded the page partway, it froze numerous times. My ad-blocker said it had blocked almost 10,000 popups before I gave up and tried Safari.)

This partisan divide is such a big part of people’s political identities, in fact, that it’s reinforced simply by “negative partisanship,” or loyalty to a party because you don’t like the other party. A Pew Research Center poll from last year found that about 40 percent of both Democrats and Republicans belong to their party because they oppose the other party’s values, rather than because they are particularly aligned with their own party.

But what if Americans’ views of the parties, particularly whichever one they don’t belong to, are, well, kind of wrong? That’s the argument of a study by scholars Douglas Ahler and Gaurav Sood that was recently published in The Journal of Politics. They had the polling firm YouGov ask American adults to estimate the size of groups in each party. For example, what percentage of Democrats are black, or lesbian, gay or bisexual? What percentage of Republicans earn more than $250,000 a year, or are age 65 or older?