Update 2/4/2017. The whole idea of measuring the average IQ of a whole country, even assuming that IQ tests are given to a representative cross-section of the population, is bogus. I should have known better than to post this. Read IQ: A Skeptic’s View by Fred Reed for Fred on Everything.
Update 10/4/2018. I recommend a study entitled Cognitive Test Scores Measure Net Nutritional Status. The authors link variations in IQ to nutrition, climate and other factors, and debunk the idea that variations in IQ are mainly genetic.
Some psychologists at the University of Rochester did a review of surveys of religion and intelligence, mainly involving North American individuals, and concluded that religious people are less intelligent on average than non-religious people. As these maps show, there is some evidence that the same variation exists among the world’s nations.
To assess the significance of these maps, you have to have an idea of just what it is that is measured on IQ tests (besides the ability to take IQ tests).
The great sociologist Peter Berger wrote that IQ is a measure of “modern consciousness,” which consists of the intellectual skills needed to function in a modern technological society. That would explain why immigrants (including Jewish immigrants) to the 19th century United States on average had lower IQs than the natives, but the U.S.-born children of the immigrants were equal to or better than the natives. It would explain why, during World War Two, Southern rural white men on average did worse on Army intelligence tests than Northern urban black men. It would explain the Flynn Effect of rising IQ in each generation.
If Berger was right, it is non-modern forms of religion, not religion as such, that are correlated with lower IQ. If he was right, IQ is not a measure of innate ability, but rather a measure of generational progress toward modernity.
Of course, not all nations embrace modernity.
I think it is safe to say that religious authorities who execute people for their beliefs do not have confidence in reason or analysis.
Click on the following links for background on the charts.
World IQ 82 by James Thompson for The Unz Review [Added 8/3/2019]
A surprising map of where the world’s atheists live by Max Fisher and Caitlin Dewey of the Washington Post.
equality by Julian Abagond.
The seven countries where the state can execute you for being an atheist by Max Fisher of the Washington Post.