Richard Lynn and Tatu Vanhanen
Westport, CT: Praeger, 2002
$64.95
256 pp.
Reviewed by Edward Miller
The thesis of Richard Lynn and Tatu Vanhanen’s IQ and the Wealth of Nations is that differences between nations in income are basically due to differences in their populations’ intelligence. Countries with more intelligent populations are better able to master complex modern technologies and hence enjoy higher standards of living. While this theory has probably occurred to others, this is the first time it has been rigorously developed and put to a quantitative test.
The heart of the book is the demonstration that national IQ and national incomes are correlated. Lynn is well suited for this exercise because he is probably the leading expert on international comparisons of IQ. In the course of other work, he has accumulated a massive database of studies in which IQ tests were given in different countries. Because there are different tests, scored in various ways, an appreciable amount of work had to be done to make all of the scores compatible. Since test scores appear to be increasing over time (for reasons that are unknown, although Lynn has speculated that improved nutrition is a major part of the explanation), scores had to be adjusted to provide for this factor as well. A natural question is whether it is even meaningful to talk about an average national IQ. By comparing cases in which a minimum of two tests had been given in the same nation, Lynn demonstrates that similar scores were achieved, thus showing that the reliability is sufficient to make international comparisons.
The book's most important finding is in 1998 there was a correlation of 0.733 between real gross domestic product and the national IQ calculated over eighty-one nations. The gross domestic products here have been calculated using published exchange rates. Since some think it is more accurate to compare national incomes in terms of what the incomes will actually purchase, results are also presented and compared for gross domestic products using purchasing power parity. For sixty-five countries with suitable data in 1998, the correlation was 0.775.
Although the subject of the book under review is IQ and national wealth, the evidence shows clearly the importance of the type of economic system. Socialist command economies have been much less favorable for economic development than have market economies. This having been established by other authors, the contribution of IQ and the Wealth of Nations lies in its demonstrating the powerful explanatory power of a single variable, the IQ of the country’s population.