A dart in the evolving science of perception and race: a new study suggests that self-described partisanship influences how a candidate with biracial skin tone is evaluated. The biracial candidate in question, of course, is Barack Obama. In a study published today in the Proceedings of the National Academy of Sciences, researchers found that self-described liberals looked at artificially lightened photographs of President Barack Obama and judged them as more representative of his actual likeness, while self-described conservative students more often chose artificially darkened photos of Obama.

First, researchers showed students a picture of a biracial man. They were told that the person was a candidate for a government job. Some in the group were told that the man supported their views; others weren't. Those who were told that the person supported their views were more likely to judge a lightened version of the person as more representative of the person's actual likeness. Those who were not rated a darkened photograph as more representative. "The more people considered the lighter versions of the candidate as representative of him, the stronger their stated intentions of voting for him."

The findings held for a candidate that all the participants knew about -- Barack Obama. Photos of him were shown before the presidential election. Working backwards, the researchers wanted to know whether photographs of Obama scored as "light" were correlated with the degree of support for him regardless of underlying political orientation. The researchers created a "conservatism" score, and performed a regression analysis. The more "people considered the lighter skin tone as representative of a candidate who shared their own ideology, the stronger their stated intentions of voting for that candidate." A third part of the study theorized that people with ingrained racial prejudice would see Obama and vote against automatically, and that the correlation was simply a matter of prejudice. Controlling for overt racial attitudes, however, the difference persisted.

The basic conclusion: the more you like a candidate, the more likely you are to "lighten" a photograph of him or her. The less likely you like a candidate, the more likely you are to "darken a photograph."

"The results from three studies suggest that political partisanship can shape which perceptual depictions of a biracial candidate people see as most representative of who he really is. Our data suggest that people's perceptions of skin tone for both novel and known candidates are systematically related to their stated voting intentions and reported voting behavior, such that both are positively correlated with the extent to which people see lighter skin tone as representative of the candidate. Across the three studies reported here, we found that partisans not only ''darken'' those with whom they disagree, but also ''lighten'' those with whom they agree. Future research should aim to clarify the specific relationship between skin tone perception and voting behavior, to determine whether ''coloring'' a biracial candidate's skin tone plays a causal role in the relationship between political partisanship and voting behavior."

Eugene Caruso, an assistant professor of behavioral science at Chicago Booth; Emily Balcetis, an assistant professor of psychology at NYU; and Nicole Mead, a postdoctoral fellow at Tilburg University, were the lead authors of the study.