ARTICLE: "Praying for health: Religious diversity may be caused by disease," The Economist, 2 August 2008, p. 83.

Corey Fincher from the U. of New Mexico, along with colleague Randy Thornhill, have calculated the number of religions per country and found a strong correlation between more religions in a country and that country having more diseases.

Tried to find the article to see the country data, but gave up after a while. Some countries listed: Old Core Canada with only 15 and Norway just 13. New Core Brazil with 159 and Gap Cote D'Ivoire with 76. Range described as 3 to 643 with average of 31.

Diseases average 200 per country with range of 178 to 248.

Theory is your basic keep-out-the-strangers thesis (reduce exposure to contagions). Countries with more religions see their people travel less and shorter distances.

Hypothesis is that more diseases causes more fracturing of religions, which in turn would suggest that if you reduce diseases, you might increase non-denominationalism (the merging of religious sects).

Probably more association than sheer causality, but interesting.

To me, the key thing to remember, though, is that having lotsa religions doesn't necessarily equate to "diversity" in the sense that we usually use the term--meaning tolerance. My guess is that, the higher your number, the more localized religions you have, in addition to the globalized ones. Conversely, the lower your number, the more likely it is you have only globalized religions. So a lower number would suggest more connectivity leading to non-denominationalism, which is typically a sign of more competitiveness among the religions (easier to switch), because the identification isn't so tied to the land.