It is best to understand first the three major theories of immigrant and ethnic-group integration. The theories are the classic and new assimilation models, the racial/ethnic disadvantage model, and the segmented assimilation model. West Indies, South Asia, Koreans and Cubans considered as the Black Americans because of their color. They have been a victim of racial discrimination and racism.
The classic assimilation theory sees immigrant/ethnic and majority groups following a "straight-line" convergence, becoming more similar over time in norms, values, behaviors, and characteristics. This theory expects those immigrants residing the longest in the host society, as well as the members of later generations, to show greater similarities with the majority group than immigrants who have spent less time in the host society. However, old West Indies remains with their culture and beliefs because of the discrimination and racism they experience from white Americans. The second generation of West Indies were able to adopt their belief and values in education. In employment most of them were engaged in self-employment, to avoid discrimination and racism. South Indians, Koreans and Cubans also believe in self employment because of the same reasons of discrimination and racism. ...
West Indies, South Asians, Koreans and Cubans live on a community where most of the same origins stay. They usually live together to ensure that they will have a mutual support in an alien land. Immigrants such as West Indies, South Asians, Koreans and Cubans, to the United States tended to maintain a strong national, cultural, and ethnic identity to their homelands. Barriers usually blocked their assimilation. Because immigrants compare socioeconomic opportunities in the host country to those in their countries of origin, they may not perceive these barriers. However, by the second or third generations, they may realize that the goal of full assimilation may be more difficult and take longer than originally presumed.
Segmented assimilation is a combination of the straight line assimilation and the racial ethnic disadvantage model. In this model others have noted that some members of immigrant groups become cut off from economic mobility, others find multiple pathways to assimilation depending on their national origins, socioeconomic status, contexts of reception in the United States, and family resources, both social and financial. They theorize that structural barriers, such as poor urban schools, cut off access to employment and other opportunities - obstacles that often are particularly severe in the case of the most disadvantaged members of immigrant groups. Such impediments can lead to stagnant or downward mobility, even as the children of other immigrants follow divergent paths toward classic straight-line assimilation.
The 1965 immigration and nationally act has increased the numbers of Asians and other nationality to migrate in US. The revision of this act has helped the immigrants to lessen the