Whether out in polite society or answering the questions of nosy psychologists, most people insist to the utmost that they’re not racist. But when those same psychologists test people's subconscious feelings, they find a much different story. More than 80 percent of white people show some measurable prejudice (pdf) against black people, for instance.

About 7 percent of white people, though, actually show a distinct lack of racism on probing psychological tests, says psychologist Robert Livingston of Northwestern University. Recently Livingston and Brian Drwecki of the University of Wisconsin studied these people to find out why they're not racist and, by implication, why the rest of us are. It turns out that the nonracists share a unique emotional style: They rarely form any negative associations, whether they're thinking about meaningless symbols or real human beings.

In their experiment, the researchers tested people’s tendency to form positive and negative associations by showing them written Chinese characters followed quickly by pictures of “ good” things—like baby seals, flowers, and waterfalls—or pictures of “bad” things, like mutilated faces, snarling dogs, and feces. (Previous research has showed that Chinese characters appear meaningless and neutral to English speakers.) The researchers presumed that the characters would take on positive or negative traits depending on what images they were paired with. And indeed, most people liked the characters that were paired with good pictures and disliked those linked to bad images.

A select few, though, did not form negative associations with Chinese characters. They made positive links just as often as anybody else, but the negative images didn’t stick in their minds. They seemed not to pay as much attention to negative information as others did and were less likely to form negative associations between two things. “They have rose-colored filters,” Livingston says.

It turns out these people are generally the same people who show no prejudice on the implicit racism test.

In this type of experiment—which has been used by other scientists studying race psychology—subjects look at pictures of faces on a screen and press one button if the face is black and another if it is white. Interspersed with the faces are words that are either positive (“glorious,” “joyful”) or pejorative(“terrible,” “nasty”). In one round, subjects use one key for white faces and positive words and another key for black faces and negative words. In another round, the keys are switched so that the white faces are matched with negative words and black faces with positive words. If a person takes longer to press the “black” key when it’s paired with the “good” key than when it’s paired with the “bad” key, psychologists believe, that comes from a subconscious resistance to associating black people with goodness—a sure sign of racial prejudice. You can take this test yourself on Harvard University's website.

The researchers say that negative associations likely have such power in most people's minds because evolution prepared us to notice bad things more than good things. “If there’s a lion hiding in a bush, you’d better see it,” Livingston says. “Whereas if there’s a tree of mangoes, it’s unfortunate if you don’t notice it, but it’s not as critical to your survival.” Since each negative association has more weight in the brain, one must overcompensate with many positive links just to get back to neutral. The psychologists aren’t clear on why some people don’t make negative associations, but they are looking for genetic and social factors that predict it.

Other recent research on race has shown that the desire to look past these powerful negative associations is, unfortunately, not very effective at decreasing people's actual level of prejudice. “It’s not a matter of teaching people that prejudice is wrong,” Livingston says. “They know that already. You need to expose them to positive associations.” So how do you motivate people to form positive feelings for people they don't like? Psychologist Linda Tropp of the University of Massachusetts at Amherst calls Livingston and Drwecki’s paper “provocative and important,” but she says that the desire to avoid being racist can compel people to seek contact with the very people they're biased against, which is known to be the best way to reduce prejudice. So maybe our conscious angels can help us silence those subconscious devils after all.