Some examples of historically oppressed groups include people of African descent, people of Jewish faith and people of Asian descent. Since oppression is closely tied to the condition of being perceived as "outsiders," the identity of oppressed groups varies regionally, and oppressed people in one area may be oppressors elsewhere.
Oppression is based on discrimination, which is based on perceived or real differences. For this reason, oppression becomes a condition foisted onto minority groups, who have less power, by majority groups, who have more. Discrimination appears in the United States in situations where a group is perceived as different from the ever-evolving standard of what is considered "normal." Some of these groups include African-Americans, Native Americans, and immigrants from Europe, Asia and Central and South America.
In other regions of the world, the evolving standard of "normal" gives rise to different forms of discrimination and oppression. For example, albinos born to black populations in Sub-Saharan Africa are often shunned for the fear that they are the result of some evil happenstance. In India, people are discriminated against and oppressed because of a complex caste system that delineates social status at birth. The dichotomy of insider versus outsider is largely responsible for determining who will be oppressed.