The Bell Curve (1970)
Based off of the book "The Bell Curve: Intelligence and Class Structure in American Life" by psychologist Richard J. Herrnstein and political scientist Charles Murray Book synopsis - "...in which the authors argue that human intelligence is substantially influenced by both inherited and environmental factors and that it is a better predictor of many personal outcomes, including financial income, job performance, birth out of wedlock, and involvement in crime than are an individual's parental socioeconomic status. They also argue that those with high intelligence, the "cognitive elite", are becoming separated from those of average and below-average intelligence. The book was controversial, especially where the authors wrote about racial differences in intelligence and discussed the implications of those differences." - Wikipedia