In The Bell Curve, Murray and Richard Herrnstein argued that since the Second World War our educational system has become very efficient at tracking high-IQ students into college, and the highest-IQ students into elite colleges. In this book, Murray continues that theme with newer data. He shows that after two generations of tracking brains into college and stocking the high-income occupations with college brains, the "cognitive elite" is now efficiently reproducing itself.
In previous generations, the elite of money married money. But it is hard to pass on the skills that made the money. Now, the elite of brains marries brains, and brains are more heritable.
Murray shows the mean white IQ of two generations of adults by the level of education they attained. I will reproduce that simple table here. What is interesting here is that, even though 50% more people graduate from college than did a generation ago, the central characteristic of those who graduated - their intelligence level - has not. The first column represents the mean IQ of people who were 25 in the mid-'80s; the second, those who were 25 in the mid-'00s:
88, 89 No degree
99, 99 High School diploma/GED
105, 104 Associate's degree
113, 113 Bachelor's degree
117, 117 Master's degree
126, 124 Ph.D., LLD, MD, DDS
The upper-middle class dominates college enrollment, especially at elite colleges. This fact is well known. Murray argues that this is true even with affirmative action. Why?
“The reason that upper-middle-class children dominate the population of elite schools is that the parents of the upper-middle class now produce a disproportionate number of the smartest children.”