Stereotypes come from a wide range of sources, many from popular literature, and are often supported by a variety of prejudices and group interests. Until the mid-19th century, most whites considered the Native American Great Plains Indians to be aristocrats. But as white people increasingly sought to drive them out of their territory, popular literature increasingly portrayed Native Americans as creatures inferior to humans as the conflict between the two escalated. This stereotype supported the group interests of the white race. Conflict between nations often produces stereotypes that demean the other: if we consider them inferior to us as "human beings," then we will have no pain of conscience when we destroy our enemies. Stereotypes are more likely to work when interracial differences can be exploited to one's advantage.
--Brooke Noel Moore, Critical Thinking