The negative stereotypes associated with many immigrant groups, for example, have largely disappeared over time. For African-Americans, civil rights laws forced integration and nondiscrimination, which, in turn, helped to change public opinion.

But psychologists have no ready roadmap for undoing such overt and especially hidden stereotypes and prejudices.

Learned at an early age
The first step may be to admit biases are learned early and are counter to our commitment to just treatment. Parents, teachers, faith leaders and other community leaders can help children question their values and beliefs and point out subtle stereotypes used by peers and in the media. Children should also be surrounded by cues that equality matters.

In his classic book, The Nature of Prejudice, the psychologist Gordon Allport observed children are more likely to grow up tolerant if they live in a home that is supportive and loving. "They feel welcome, accepted, loved, no matter what they do."

In such an environment, different views are welcomed, punishment is not harsh or capricious, and these children generally think of people positively and carry a sense of goodwill and even affection.

Community matters
Integration, by itself, has not been shown to produce dramatic changes in attitudes and behavior. But many studies show when people work together in a structured environment to solve shared problems through community service, their attitudes about diversity can change dramatically.

By including members of other groups in a task, children begin to think of themselves as part of a larger community in which everyone has skills and can contribute. Such experiences have been shown to improve attitudes across racial lines and between people old and young.

There also is preliminary evidence that unconscious attitudes, contrary to initial expectations, may be malleable. For example, imagining strong women leaders or seeing positive role models of African Americans has been shown to, at least temporarily, change unconscious biases.

'Feeling' unconscious bias
But there is another aspect of the very experience of taking a test of hidden bias that may be helpful. Many test takers can "feel" their hidden prejudices as they perform the tests.

They can feel themselves unable to respond as rapidly to (for example) old + good concepts than young + good concepts. The very act of taking the tests can force hidden biases into the conscious part of the mind.

We would like to believe that when a person has a conscious commitment to change, the very act of discovering one's hidden biases can propel one to act to correct for it. It may not be possible to avoid the automatic stereotype or prejudice, but it is certainly possible to consciously rectify it.

Committing to change
If people are aware of their hidden biases, they can monitor and attempt to ameliorate hidden attitudes before they are expressed through behavior. This compensation can include attention to language, body language and to the stigmatization felt by target groups.

Common sense and research evidence also suggest that a change in behavior can modify beliefs and attitudes. It would seem logical that a conscious decision to be egalitarian might lead one to widen one's circle of friends and knowledge of other groups. Such efforts may, over time, reduce the strength of unconscious biases.

It can be easy to reject the results of the tests as "not me" when you first encounter them. But that's the easy path. To ask where these biases come from, what they mean, and what we can do about them is the harder task.