But the critics persist. Philip Tetlock, a professor of organizational behavior in the business school at the University of California at Berkeley, and Ohio State University psychology professor Hal Arkes argue that Jesse Jackson might score poorly on the test. They cite the civil rights leader's statement a decade ago that there was nothing more painful at that stage of his life "than to walk down the street and hear footsteps and start thinking about robbery. Then look around and see somebody white and feel relieved."
If a prominent black civil rights leader could hold such a bias, Tetlock and Arkes ask, what do bias scores really mean? Whatever the IAT is measuring, Tetlock and Arkes argue, it is not what people would call discrimination -- no one would dream of accusing Jesse Jackson of harboring feelings of hostility toward African Americans.
Harvard's Mahzarin Banaji is one of three researchers who developed the Implicit Association Test.
Banaji says Tetlock and Arkes are relying on an outmoded notion of discrimination. The IAT research shows that hostility is not needed for discrimination to occur. Women and minorities can just as easily harbor biases, absorbed from the larger culture, that can lead them to discriminate against people like themselves.
Tetlock says he thinks the IAT research project is drawing conclusions much more sweeping than are justified.
"One of the key points in contention is not a psychological point, it is a political point," says Tetlock. "It is where we are going to set our threshold of proof for saying something represents prejudice. My view is the implicit prejudice program sets the threshold at a historical low."
By the standards of slavery and segregation, the critics argue, delays in mental associations are trivial. "We've come a long way from Selma, Alabama, if we have to calibrate prejudice in milliseconds," says Tetlock.
But the biases that the tests uncover are not trivial, Banaji counters. Their consequences, while subtler, could be devastating. In settings such as the criminal justice system, she argues, lives may hang in the balance.
In their most controversial argument, Tetlock and Arkes asked whether some implicit biases might simply be politically incorrect truths. By comparing national statistics of violent crime against census figures of different ethnic groups, the researchers argued it was more likely for a violent crime to be perpetrated by an African American man than a white man. Would it not therefore be rational, they asked, for people to hold biases against blacks?
Even here, however, rationality did not appear to be the prime mover, Banaji argues. Even if whites and blacks committed crimes at exactly the same rate, Banaji says, people would assign greater weight to the black crimes. This phenomenon is known as an illusory correlation: Aberrational behavior by a member of a minority group is not only given greater prominence in the mind but is also more easily associated with the entire group, rather than just the individual. "When in-groups do bad things, we think it is individual behavior or circumstance," says Jerry Kang, a UCLA law professor who is interested in policy applications of the research. "I screw up because it is a bad day; others screw up because they are incompetent."
THE APPARENT ABILITY OF THE IMPLICIT ASSOCIATION TEST TO DETECT HIDDEN ATTITUDES AND PREDICT BEHAVIOR has raised questions about its potential uses. Might it predict, for example, which police officers are likely to mistakenly shoot an unarmed black man? Should such tests be used to cull juries of people with high bias scores? Might employers use such tests to weed out potential racists? Might employees trying to prove discrimination demand that their bosses take bias tests?
The problem, Banaji says, is that all those uses assume that someone who shows bias on the test will always act in a biased manner. Because this isn't true, Banaji and her colleagues argue against the use of the IAT as a selection tool or a means to prove discrimination. Banaji says she and her colleagues will testify in court against any attempt to use the test to identify biased individuals.
Another reason to limit the IAT's use: Research has shown that individuals who are highly motivated can successfully fool the tests by temporarily holding counter-stereotypes in their minds. (Other attempts to fool the tests -- such as consciously attempting to respond faster or slower -- tend to change results only slightly, if at all, Banaji says.) Banaji hesitates to perform real-world studies that examine, for instance, whether police officers with the most bias are the most likely to shoot an unarmed suspect in an ambiguous situation, because the results of such studies could be subpoenaed and used in lawsuits against police departments. The researchers say they want to keep the focus of the tests on public education and research. They are wary of having the tests used in lawsuits, because if people feared their results might one day be used against them, they would be hesitant to use the tests for personal education.
Banaji says she is keenly aware that psychology has a long history of tests -- starting with the "lie-detector" polygraph -- that have been hyped and misused. Personality tests that lack the rigor of the Implicit Association Test have been widely used by companies in employee training and even hiring. Atop Banaji's desk at work is a bust of a human skull marked with different brain areas once thought to be responsible for different emotions: a representation of the discredited science of phrenology. The bust is a daily warning about the many failed ways science has promised to unlock people's minds and personalities.
But even as Banaji hears from critics who say the Implicit Association Test, which is not patented, will get misused, some proponents tell her it would be unethical not to use the test to screen officials who make life-and-death decisions about others. One test in a British jail showed that, compared with other criminals, pedophiles had implicit associations linking children and sexual attraction. Should such tests be used to determine which pedophiles have been rehabilitated and should be eligible for parole or, more controversially, as a law enforcement tool to evaluate which individuals are at risk of harming children?
"People ask me, 'How do you sleep at night knowing this can be misused?'" Banaji says. "Others ask me, 'How do you sleep at night knowing this won't be used fully?'"
IN SEPTEMBER, 50 TOP LEHMAN BROTHERS EXECUTIVES GATHERED IN A CONFERENCE ROOM ON THE FIFTH FLOOR OF THE PALACE HOTEL on Madison Avenue, across from New York's St. Patrick's Cathedral. They were a self-assured, competitive bunch, the type of crowd that usually views academics with skepticism. The executives had assembled for one of the leadership training programs that the firm mandates, and the mood in the room was very much "uh-huh, uh-huh," and "here we go again," says Barbara Byrne, a senior executive at the company who was present.
Banaji told the executives she was going to test their skills of observation. She played a video of a basketball game. Shot in black-and-white, the video showed a swift series of basketball passes between players with rapidly changing positions. Banaji asked the executives to count the number of passes. The group loved competitive exercises. As soon as the short clip was over, answers came flying from all sides: Five! Seven! Eleven!
Banaji asked whether anyone had seen anything unusual? No one had noticed anything out of place. Banaji played the video again, this time instructing her audience not to pay any attention to the basketball passes. Halfway through the video clip, a woman with an open umbrella slowly walked through the frame from one end to the other. Stunned at what they had missed, the executives collapsed in helpless laughter.
"I sat there and said, God, it wasn't subtle," says Byrne. "It was a woman with an open umbrella. It was right in front of your eyes. But you were so focused on counting the basketballs, that part of your brain was not functioning."
Banaji's point was that human beings filter what they see through the lenses of their own expectations. People believe they are acting rationally, but numerous psychological tests prove that subtle cues influence people all the time without their knowledge.
"You thought to yourself, Maybe [hidden biases] could influence me in other ways," Byrne says.
No one knows exactly why people develop implicit biases. Living in a diverse neighborhood does not in itself seem to reduce bias, but having close friendships with people from other ethnic groups does appear to lower bias, the IAT researchers have found. Saj-nicole Joni, who is white, for example, did not have test results showing a race bias and said she has long been close friends with an African American woman. Morgan Walls, an African American woman who works at the Peace Corps in the District, used to work in Thailand and has retained her connections with Asia. Her test suggested no bias toward European Americans or Asian Americans. Jeff Chenoweth, the director of national operations at the Catholic Legal Immigration Network in Washington, appeared tohave no bias against Arab Muslims compared with people from other parts of the world. As he took the tests, Chenoweth, a white man and a devout evangelical, said he was planning to have two Iraqi Shiite Muslims over to his home for Christmas dinner. "I've lived as a minority in an Arab country and have 10 close friends who are Arab," he said.
Banaji herself shows no implicit biases against gays or Jews -- a result, she believes, of an upbringing where explicit biases against those groups were largely nonexistent.
There is growing evidence that implicit attitudes can be changed through exposure to counter-stereotypes. When the race test is administered by a black man, test takers' implicit bias toward blacks is reduced, says Irene Blair, a University of Colorado psychologist who recently conducted a review of studies that looked at how attitudes could be changed. Volunteers who mentally visualized a strong woman for a few seconds -- some thought of athletes, some thought of professionals, some thought of the strength it takes to be a homemaker -- had lower bias scores on gender tests. Having people think of black exemplars such as Bill Cosby or Michael Jordan lowered race bias scores. One experiment found that stereotypes about women became weaker after test takers watched a Chinese woman use chopsticks and became stronger after they watched the woman put on makeup. Interventions as brief as a few seconds had effects that lasted at least as long as 24 hours. But the volunteers were not aware of their attitudes having been changed.
Having counter-stereotypical experiences, in other words, might be much like going on a new diet with healthier food. Just as healthy eating can have a subtle impact on how people look and feel, counter-stereotypical experiences sustained throughout one's life seem to subtly change how one thinks. But, Banaji says, such experiences may not eliminate bias altogether.
Banaji believes that conscious efforts are needed to fight what she calls ordinary prejudice, the primitive brain filtering the world through its biased lenses without the conscious part of the brain being aware of it. Tests have shown, for example, that when people are given a sense of power, they show greater biases than they did before. As a result, workplaces that are explicitly more egalitarian might be implicitly less biased, she says. Since Mullainathan found startling differences in his résumé study, he says, he has come to believe that personal identifiers should be removed from résumés to make evaluations more fair. Another area highly prone to implicit biases is job interviews, says Max Bazerman of Harvard Business School. "What you need to do is look at objective measures separate from the interview."