At a recent workshop presented by the UC Berkeley Institute for Human Development, McKown addressed an audience of educators, school counselors and administrators to bring to light this important issue, as well as to discuss strategies for preventing stereotyping.

"First, multicultural curricula that simply expose children to positive images of people from different ethnic groups do not work," he said. "They are not harmful; but they are not helpful either." He continued with useful strategies.

"For younger children, for example, simply teaching children to notice the individuating qualities of people reduces stereotyping," he said. He explained how a researcher showed white second and fifth graders slides of African Americans until the children had correctly associated the names with the faces. This had a marked effect on children's level of stereotyping.

A Canadian curriculum used a similar strategy. Children spent several weeks "getting to know" a fictional class of 30 children from diverse ethnic backgrounds. This curriculum had a dramatic and lasting effect on children's level of stereotyping.

"Both interventions probably worked because they trained children to notice what makes people unique, weakening the sway of ethnicity," McKown said.

In ethnically mixed classrooms, any practice that increases children's dependence on one another for success and equalizes social status is likely to reduce stereotyping.

"The key is to structure the activity so that children depend on each other for success," McKown said. "Assigning a group a task and making the final grade for each student the average of all students' performance will reduce stereotyping - 'if my grade depends on my partner's, I have a vested interest in my partner's success.' This strategy has been shown to increase learning and reduce stereotypes.

"It is critical that educators know about stereotyping and children's well-being because ethnically mixed schools represent a unique opportunity to promote tolerance, and in so doing, to positively affect children's well-being," he said.

McKown surprised the participants when he told them that children in the United States come to understand ethnicity concepts between the ages of 3 and 4. At around age 6, children become accurate at sorting people by ethnicity, and at around age 7 or 8, children understand that ethnicity does not change. "So by second or third grade," McKown explained, "children have an adult-like idea of what ethnicity is."

McKown believes there are costs associated with stereotyping. "First, there is little doubt that stereotypes are at play in hate crimes such as the murder of Eddie Araujo," he said. "Second, we know that the more children are the targets of stereotypes, the more likely they are to be depressed." He also explained that those who endorse stereotypes have more anxiety. "The clear message is that stereotypes are bad for the mental health of perpetrator and target alike."

"Stereotypes can also affect children's academic achievement," he continued. In his research, McKown found evidence that when African American and Latino children are aware that others judge people because of their ethnicity, the conditions of testing can affect their performance.

"Specifically, African American and Latino children do worse on a cognitive task when it is described as a test of ability than when it is described as not a test of ability," he said.

McKown concluded that pervasive ethnic stereotypes about academic ability become activated in the testing situation, creating a self-fulfilling prophecy. The more the student is aware of negative stereotypes regarding his or her particular ethnic group, the more likely he or she will do badly on a test that is supposed to show intelligence or academic ability. McKown also explained that this can happen very early in a child's school experience. "As early as 7, but definitely by age 9," he said, "a significant proportion of African American and Latino children are aware of others' stereotypes."