The sociology of race and ethnic relations is the study of social, political, and economic relations between races and ethnicities at all levels of society. This area encompasses the study of racism, residential segregation, and other complex social processes between different racial and ethnic groups. The sociological analysis of race and ethnicity frequently interacts with other areas of sociology such as stratification and social psychology, as well as with postcolonial theory.
At the level of political policy, ethnic relations is discussed in terms of either assimilationism or multiculturalism. Anti-racism forms another style of policy, particularly popular in the 1960s and 1970s. At the level of academic inquiry, ethnic relations is discussed either by the experiences of individual racial-ethnic groups or else by overarching theoretical issues.
Marx described society as having nine "great" classes, the capitalist class and the working class, with the middle classes falling in behind one or the other as they see fit. He hoped for the working class to rise up against the capitalist class in an attempt to stop the exploitation of the working class. He blamed part of their failure to organize on the capitalist class, as they separated black and white laborers. This separation, specifically between Blacks and Whites in America, contributed to racism. Marx attributes capitalism's contribution to racism through segmented labor markets and a racial inequality of earnings.
Weber laid the foundations for a micro-sociology of ethnic relations beginning in 1906. Weber argued that biological traits could not be the basis for group foundation unless they were conceived as shared characteristics. It was this shared perception and common customs that create and distinguish one ethnicity from another. This differs from the views of many of his contemporaries who believed that an ethnic group was formed from biological similarities alone apart from social perception of membership in a group.