I recall vividly the Rev. Dr. Martin Luther King Jr. speaking to members of the American Psychological Association in Washington a few months before his assassination. He urged us not to focus only on helping people adjust to society, but also on helping make society better for all people. One obvious need was to help eradicate racial prejudice.

Since then we have made considerable progress, aided in part by the efforts of psychologists. Still, we find prejudice very much with us. Incidents of racial prejudice, both blatant and subtle, provide fodder for heated discussions in newspaper columns and TV talk shows. Where does it come from? Why does it persist, despite more than a half century of national effort to eradicate it?

A large part of the answer, it seems, lies in the way children learn and in the very early age at which prejudice takes root. Multidisciplinary studies in cognitive science, child development, social perception, and educational research are now enriching our understanding of this crucial area of early childhood learning.

A recent research study, for example, showed that young children naturally group other children on the basis of skin color. Moreover, they assume that children who are more like them in appearance will share common interests and values.

This finding is consistent with previous psychological research in cognitive development and attitude formation, which shows that the way children learn makes it natural for them to acquire prejudices along the way. Unlike the Rogers and Hammerstein message in South Pacific that prejudice "has got to be carefully taught," normal learning entails grouping objects and people into categories: birds, fish, policemen, schoolteachers, black children, and white children. Attitudinal and emotional components quickly become associated with these groups.

I recall a striking example of such early learning while watching TV with my son when he had barely learned to speak. I was absorbed in the performance of Ella Fitzgerald when he interrupted to ask, "Daddy, when is she going to run the cleaner?"

My brother had a somewhat similar experience. On passing a well-dressed African American man, while walking with his little boy, the 3-year-old waved, flashed a big smile and called out, "Hello, trash man!"

As parents who are strong advocates of racial equality, we were taken aback when our children initially assumed that all African American men were trash men and African American women cleaning women.

Such experiences indicate that parents need to talk about racial differences rather than assume, that, if they ignore race, their children will not notice it or will assume that it is unimportant. Young children are learning machines, taking in prodigious amounts of information from the world around them, organizing it and remembering it. This initial learning is, however, replete with misconceptions and overgeneralizations of the "if it looks like a duck it must be a duck" kind, so that much subsequent learning requires children to unlearn things that they "know." Not every species that swims is a fish; not every bird can fly; not all teachers are women.

Racial differences are a natural part of a child's learning, and parents should neither ignore them nor feel that they are not competent to teach the child about them. And when a child makes an incorrect generalization about race, the parent should simply correct it. "Yes, that lady looks like Clara who runs the cleaner, but she is a singer, and her name is Ella" and "That man does look something like the men who collect the trash, but he is a doctor, like Dr. Frank," in the same way that we tell a child: "That looks like a bird because it can fly, but it's called a bat."

As a society, we have reduced our prejudices and can continue to do so. A few generations ago many ethnic and religious groups, including Americans of Irish, Italian, and Polish background, were targets of prejudice; today, they are seldom differentiated from other Americans. A majority of the Supreme Court justices today are Catholic. At one time this would have created a furor in the media and swelled the ranks of the Ku Klux Klan; today, the public response to this situation is one protracted yawn.

So we trudge along on the road to a more perfect Union: two steps forward, one back - each new generation learning a particular set of biases early on. Fortunately, we are now learning more about how to overcome them, starting at an early age.

E-mail John Rooney at rooney@lasalle.edu.