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Light or dark? When researchers asked students to choose the photo that best represents Barack Obama's "true essence," the response depended on political persuasion.

Eugene Caruso, Nicole Mead, and Emily Balcetis

Skin Color Is in the Eye of the Beholder

A new study suggests that we mentally alter politicians' skin tones to match how we feel about them. When presented with three photos of President Barack Obama and asked to choose which was most representative of him, liberals tended to pick a shot in which his skin had been digitally lightened, whereas conservatives tended to choose a darkened version.

Previous studies indicate that people tend to view lighter skin more favorably than they do darker skin. Darker skin tones are associated with more negative stereotypes, says Eugene Caruso, a social psychologist at the University of Chicago in Illinois and co-author of the new study. Clearly, skin tone affects how we perceive an individual. But can our perception of an individual affect how we see their skin tone?

To find out, Caruso and his colleagues quizzed undergraduate students--about 90% were white and 10% were black--on their political views and then presented them with three photos of Obama. The researchers had doctored two of the photos. In one, they digitally lightened Obama's skin tone slightly, and in the other they darkened his skin tone. The researchers then asked the students to choose the photo that best captured the candidate's "true essence."

Not everyone picked a single photo, but among those who did, a clear pattern emerged: Liberals were roughly twice as likely to choose the lightened version of Obama, with 19% choosing the lightened version versus 10% of conservatives. Conservatives were more likely to choose the darkened version--25% versus 15%--the authors report online today in the Proceedings of the National Academy of Sciences. Even when the researchers controlled for racial attitudes by using standard tests designed to measure prejudice, the difference persisted. Moreover, students who chose the lightened version of Obama as most representative were more likely to have voted for him in the election, regardless of political affiliation.

In a separate study, Caruso and colleagues invented a racially ambiguous politician they said was being considered for a position at the U.S. Department of Education. A different group of students, again about 90% white and 10% black, saw an unaltered photo of the candidate and read his biography. The researchers then asked the participants about their positions on education reform. They told half that the candidate mostly agreed with them. The other half were told that the candidate mostly disagreed with them. When asked to pick which altered photo of the candidate was more representative, students who thought the candidate agreed with their views were two-and-a-half times more likely to chose the lightened photo. Those who thought the candidate disagreed with them were two-and-a-half times more likely to choose the darkened photo.

The findings don't appear to hold for racially unambiguous candidates, however. When participants were presented with three versions of John McCain--each with different skin colors--skin tone had no effect on their choices. The more racial ambiguity, Caruso says, "the more room there is for judgmental bias."

The study is "superb" and "timely," says David Dunning, a social psychologist at Cornell University. "This is the first study to show how the impact of political allegiances can extend down to our literal perception of the physical world and the people in it," he says. "The take-home message is that social stereotypes can be quite subtle, and they can work in ways that lie far below our awareness," he says.

"These studies aren't really about political partisanship," says Mahzarin Banaji, a social psychologist at Harvard University. "They tell us that, in our minds, light skin is a stand-in for what's good; and dark skin is a stand-in for what's bad." We strive to choose our leaders based on their competence and character rather than skin color, she adds, "Yet we cannot shake that off when making consequential decisions."