In the mid-20th century, a new generation of historians began to review the beginnings of American experience and had been looking over the original documents related to the establishment of the American colony for years. Their study shows that there is no ethnic belief in the 19th and 19th centuries. Ethnicity is born of folk beliefs and ideology of human differences, which is a social invention. Historians documented how the ideological tribes penetrated our culture and consciousness.
Race and its ideology on human differences are derived from the background of slavery in Africa. But many people in history are enslaved and do not impose racial ideology. When seeing the colonies of the 17th century, the United States just legalized slavery in Africa and its descendants (after 1660) before enacting the law, and several facts became clear. In the latter part of the 17th century, labor demand increased significantly. It is clear that neither the Irish nor the Indians have become good slaves. More importantly, the real threat to social order is Caucasians liberated by the poor who demands land and privileges that upper class colonial governments reject. Colonial leaders believe that turning to African workers can ease many poor white people
Ultimately, the "race" as an ideology of the human difference spread to other parts of the world afterwards. It became a strategy to divide, rank and control colonists used by colonists. But it is not limited to colonial situation. In the late nineteenth century, Europeans used it to rank each other, and kept people's social, economic and political inequality. During World War II, the Nazis under Adolf Hitler condemns the expansion of the difference between "race" ideology and "race" and enables them to achieve a logical purpose. For example, 11 million "inferior race" (destroy, Jewish, gypsies, Africans, homosexuals, barbaric acts that the Holocaust can not express)