“Reality has a well-known liberal bias.” —Stephen Colbert, White House Correspondents’ Dinner 2006 “Comedians have a well-known liberal bias.” —Bob

Bob might be correct, but that doesn’t mean Colbert is wrong. One of the important questions of dueling fact perceptions is whether the biases driving them— of preferred values onto perceived facts, , to social groups—are symmetric across ideologies. Do conservatives project their beliefs into biased perceptions more than liberals do? Or do both sides do this relatively equally?

Responses to a recent article suggest that some readers clearly believe that dueling fact perceptions are a phenomenon of the Right:

“What it says to me is that conservatives always tend towards any narrative that supports their viewpoint of the world. That conservatives more easily coalesce with each other when it comes to ideas. Liberals on the other hand have broader horizons and while they too tend towards narratives that support their beliefs they are far more open to facts.” “The center and center-left in the US are informed by facts about reality, while the right and far-right make decisions based entirely on emotion. And the best part? The right accuses the left of doing exactly what they do. Their only weapon is projection.”

“Both-siderism” is surely a vice, because each ideological group is not always equally guilty of the same flaws. But our own ideological biases may blind us to what is really going on. What does the evidence say about perceptions across the aisle?

In a particularly clever study, Anthony Washburn and Linda Skitka created presentations of information that could easily be interpreted one way, but actually show the opposite when closely examined. When asked what the information suggested, both conservatives and liberals interpreted the evidence in ways that bolstered their initial views. And when errors were pointed out, both sides rejected this inconvenient evidence at the same rate. The study concludes that “liberals and conservatives appear to be similarly motivated to deny scientific claims that are inconsistent with their attitudes.”

In our studies on the origins of dueling fact perceptions, liberals projected their values as much as conservatives did. Extremes of individualism and collectivism predicted perceptions of and . Extremes of theism and humanism predicted perceptions of . Conservative values like Sanctity, Loyalty, and Authority predicted perceptions of the national debt, vaccines, false convictions, and the effects of immigration. But so did liberal moral values of Care and Fairness. [Note 1]

Liberal fact perceptions often match the most widely available evidence and information. But that does not mean that this is why many liberals hold those perceptions. When empirical evidence and value predispositions point in the same direction, it may not be obvious which is the true driver of perceptions.

Another way to address the question of whether one partisan group has more biased perceptions is the degree of certainty they hold. Here our research does not find symmetry, but a distinct imbalance. Liberal ideology predicts substantially greater certainty across a range of perceptions. And the liberal value of Care is the single strongest predictor. Certainty bolsters all of the psychological mechanisms that lead to denial and rejection of new evidence. It also leads to refusal to compromise or to deliberate with those who disagree.

The same imbalance between liberals and conservatives applies to the rejection of others who hold different perceptions. In our experiments, both liberals and conservatives were less willing to work with someone who held opposing perceptions. But liberals took a harder line against them. Across several different perceptual disputes, conservatives were on average 37 percent less likely to want to work with our fictional man Bob when he saw the facts of the world differently. But liberals were 56 percent less likely. Liberals may be less indulgent of perceptual differences than they are of cultural differences. In other words, tolerance is for , not reality.

Many scholars have argued that conservatives are more rigid, intolerant, and certain. But in regard to factual perceptions, the evidence does not bear this out. Both liberals and conservatives can fall prey to the psychological forces that make perceptions subservient to values.