In the article, "Stereotypes and Prejudices," the author writes, "Our society often innocently creates and perpetuates stereotypes, but these stereotypes often lead to unfair discrimination and persecution when the stereotype is unfavorable." Some examples that the author reveals are that from the Genocide and Holocaust. Here, the Jews were discriminated, persecuted, murdered, and mocked by the Nazi Germans.
In addition, the author speaks of how the movie industry portrayed African-Americans as being unintelligent, lazy, or violence-prone.
As a result of viewing these stereotyped pictures of African-Americans, for example, prejudice against African-Americans has been encouraged.
http://remember.org/guide/history-root-stereotypes