Since the Industrial Revolution, average IQ of whites have been declining rapidly due to the low birth rate of intelligent upper-class and middle-class and high fertility of the lower class. Before the Industrial Revolution, the childhood mortality was 50% but nowadays, childhood mortality is below 1%. In America, intelligence and fertility are correlated at -0.006 among men and -0.196 among women. This decline in intelligence due to differing fertility among classes is called ‘the Woodley Effect’, named after a Scottish baron named Michael Anthony Woodley of Menie. According to Roger Pearson, an English scientist, the average IQ of Asians surpassed that of Whites around year 1900, the end of 19th century and beginning of 20th century.

In the 1700s, the English were the race that is 2nd most intelligent, next only to Jews. However, according to Bruce Charlton, English average IQ declined by 30 pts since the Georgian period. According to Michael Anthony Woodley of Menie, English IQ declined by 13.35 points between 1889 and 2004. (https://www.sciencedirect.com/science/article/abs/pii/S0160289613000470) Woodley also claims that England is the nation in Europe with the most rapid IQ decline with loss of 1.26 pts IQ per decade. According to Richard Lynn, a Scot from Edinburgh, the average English IQ will hit 87 by the end of this century. However, Edward Dutton disagrees and claims that English average IQ will hit 85 by the end of the century.

Germany was a latecomer to Industrial Revolution. Because Germans were less affected by Industrial Revolution, their intelligence eventually surpassed that of the French and English. It is estimated that Germans had average IQ of 120-115 in 1870s, the golden age of Prussia. Germans remained as the 2nd most intelligent race after Jews till mid 1900s. But in the mid 1900s, Koreans became the 2nd most intelligent race after Jews. In 1960, the average German IQ was 105, but it was 102 in 1990, and 99 in 2020.