While Koch and Simmons ignored class divisions within the African American community by not attempting to sample rural blacks, they did attempt to deal with the subject of class diversity within the Mexican American community. Mexican Americans occupied a very malleable place in the hierarchy of race in the 1920s and still do today. The racial catego- rization of Mexican Americans depended in part upon their social class. Those of poorer backgrounds were treated as a definitive racial group to be separated from whites. Those of middle-class or more elite backgrounds were referred to as white or as having more pure "Spanish" blood.3 In the tests conducted by Koch and Simmons, this malleability existed and was tied not only to observations of social class but also by how lightly or darkly pigmented the individual Mexican American test subject was. Koch and Simmons kept a log on the pigmentation levels of the African American sample as well. For both Mexican Americans and African Americans (the skin pigmentation for whites was not analyzed) the pigmen- tation levels of "light," "intermediate," and "dark" were used; breakdowns of the test scores were given along these categories (Koch and Simmons, 1926:83).
Their way of categorizing pigmentation level doesn't make sense to me. However, l do agree that when doing a study like this, social class should be taking into consideration. A poor kid could be smarted then a rich kid, obviously, but things like the education they had and the environment they were raised could make an impact on their intelligence level.