What explains the tremendous cross-national variation in religious devotion? IQ? Race?

If you're like me, you could use a break from all the coronavirus, stuff, so let's focus for a moment on race, IQ, and religion. The 2010-2014 World Values Survey asked 88,042 around the world whether they were religious, not religious, or atheist. Here are the percentages listed by country who answered that they were religious:

Percent religious

Pakistan    99.7
Georgia   97.1
Ghana   97.0
Nigeria   95.9
Rwanda   95.9
Qatar   93.8
South Africa   90.7
Haiti  90.3 
India  88.8
Armenia  88.5
Yemen   86.3
Poland   86.2
Turkey   83.5
Colombia  82.5
Morocco   82.4
Peru   81.5
Romania  81.4
Philippines   80.7
South Africa  80.0
Brazil  79.7
Trinidad and Tobago  78.8
Cyprus   78.3
Iraq   76.8
Algeria   74.2
Mexico   74.2
Azerbaijan  73.2
Palestine  72.4
Ecuador   71.1
Libya   68.5
Ukraine   68.3
Argentina   67.8
USA   67.0

Total Sample  66.7

Tunisia   65.1
Slovenia   64.2
Lebanon   63.6
Belarus   62.2
Kazakhstan   61.7
Malaysia   53.7
Russia   53.1
Singapore   53.1
Uruguay   50.8
Chile   50.3
Germany   49.5
Uzbekistan   48.7
Netherlands    43.8
Taiwan   43.3
Netherlands   43.8
New Zealand   42.7
Spain   40.0
Thailand   32.0
Sweden   31.2
Estonia   30.9
Japan   20.9
Hong Kong  19.8
China  12.5

First, the world is quite religious: two-thirds of the total sample described themselves this way. On the other hand, there is tremendous variation. Almost all Pakistanis are religious, while few Chinese are.

On the issue of race, noticeable patterns emerge. South Asians and blacks tend to be very religious, and while the numbers here suggest Islam is associated with greater religiosity, countries like India, Ghana, and Rwanda show that South Asians and blacks do not need to be Muslim to be highly religious. The least religious country with lots of blacks is Trinidad and Tobago, but it is still well above average.

On the other end, East Asians are typically secular. China is at the bottom with 12.5% religious. Filipinos are the exception. This raises the importance of IQ in explaining religiosity. Depending on the estimate, mean IQ for the Philippines is between 74 and 86, and research clearly shows that lower IQ people tend to be more devout.

Europeans vary a lot with levels from 97.1% in Georgia down to 30.9% in Estonia.  Historical factors are important, but a virtue of focusing on IQ is that it helps simplify the world--a major goal of science. Estonians, for example, have a mean IQ of around 100, while it is in the low to mid-90s in Georgia.

Muslim-dominated societies vary quite a bit, too, from 99.7% religious (Pakistan) to 48.7% (Uzbekistan). IQ appears to be a little higher in Uzbekistan. Malaysia, another somewhat secular,  Muslim-dominated country (53.7% religious) has a mean IQ somewhere in the low-to-mid 90s. Overall, Muslim countries are religious.

Latin Americans countries are also fairly devout. On the high end, 82.5% of Colombians are religious, and on the low end, 50.3% of Chileans. Again, IQ might help explain the pattern: it's in the high 80s in Chile, but the low 80s in Colombia.

It looks like any association between race, ethnicity and religious devotion is, in large part, simply a reflection of differences in IQ.  The simple three-race categorization works very well: blacks (low IQ/high religiosity), whites (medium IQ/medium religiosity), and East Asians (not Filipinos) (high IQ/low religiosity). We could add South Asians as well (low IQ/high religiosity).