Read this excerpt from pg 172-173 in Inequality by Design: Cracking the Bell Curve Myth / Claude S. Fischer ... [et al.]
"Consider this situation: Members of a minority, many of whom were brought to this country as slave labor, are at the bottom of the social ladder. They do the dirty work, when they have work. The rest of the society considers them violent and stupid and discriminates against them. Over the years, tension between minority and majority has occasionally broken out in deadly riots. In the past, minority children were compelled to go to segregated schools and did poorly academically. Even now, minority children drop out of school relatively early and often get into trouble with the law. Schools with mx`any minority children are seen as problem-ridden , so majority parents sometimes move out of the school district or send their children to private schools. And, as might be expected, the minority children do worse on standardized tests than majority children do. What is this minority?
Koreans in Japan.
Koreans, who are of the same "racial" stock as Japanese and who in the United States do about as well academically as Americans of Japanese origin (that is, above average), are distinctively "dumb" in Japan. The explanation cannot be racial, nor even cultural in any simple way. The explanation is that Koreans, whose nation was a colony of japan for about a half-centry, have formed a lower-caste group in Japan.
Consider another case: immigrants flood into the United States to take low-wage jobs. They are "swarthier" and more "primitive' than most Americans they seem unwilling or unable to assimilate; they are suspected of criminal behavior; and they threaten native workers' jobs. Together with other newcomers, these immigrants provoke a backlash against easy immigration into the country. Objective tests show that immigrants are low in intelligence; and their children do poorly in school. Who does this describe?
Polish Jews in the 1900s and 1910s.
These same Polish Jews, whose descendants now do well both economically and on tests, were scorned when tehy came. Many scholars of teh day believed that the Jes, along with Italians and other "dark" types, were dim-witted. Can race or genes explain what happens in the intervening seventy years or so? No, but social location can. As a peripheral and subservient group in the early twentieth century, Polish Jews were failures, even in school. As they came to be accepted in American society, their position and their "intelligence rose."
Our argument...is that a racial or ethnic group's POSITION in SOCIETY determines its measured intelligence rather than vice versa. Some ethnic groups find themselves in inferior positions through conqeust or capture (e.g., the Irish in Great Britain, Maori in New Zealand, Africans, Mexicans, and Indians in the United States). These are the groups that suffer the most drastic and lasting effects of subordination. Other minority groups enter a society through immigration, often made under economic duress (e.g. Italians in the US, Eastern-origin Jews in Israel, Turks in Germany). These groups typically move closer to equality faster. In either case, subordination leads to low performance in three ways...."