From Nature:
Prejudice may seem inescapable, but scientists now report the first group of people who seem not to form racial stereotypes. Children with a neurodevelopmental disorder called Williams syndrome (WS) are overly friendly because they do not fear strangers. Now, a study shows that these children also do not develop negative attitudes about other ethnic groups, even though they show patterns of gender stereotyping found in other children. “This is the first evidence that different forms of stereotypes are biologically dissociable,” says Andreas Meyer-Lindenberg, director of the Central Institute of Mental Health in Mannheim, Germany, who led the study published today in Current Biology.
Adults with WS show abnormal activity in a brain structure called the amygdala, which is involved in responding to social threats and triggering unconscious negative emotional reactions to other races. Racial bias has been tied to fear: adults are more likely to associate negative objects and events, such as electric shocks, with people of other ethnic groups compared with those of their own group. But according to Meyer-Lindenberg, his latest study offers the strongest evidence so far that social fear leads to racial stereotyping.
More here.