Intelligence, equal opportunity and social equality

Christopher Badcock Ph.D. on human intelligence:

Equal opportunities and increasing social equality in certain respects means that a person’s innate qualities count for more than they may have done in the past. This is demonstrably so in the case of intelligence and education. In 1930, Ivy League graduates had IQs just over 1 standard deviation (SD) above the population mean. By 1990 it was almost 2.7 SDs above, and as Herrnstein and Murray pointed out, “when a society makes good on the ideal of letting every youngster have equal access to the things that allow cognitive ability to develop, it is in effect driving the environmental component of IQ variation closer and closer to nil.” But of course by the same reasoning it is also driving the genetic factor closer and closer to being the dominant one, and what is true of IQ in particular is also likely to be generally true of other cognitive skills and abilities.