They therefore predict that patterns of behaviour which promote group exclusivity will be stronger in disease-ridden areas.

ECONOMIST: Religious diversity may be caused by disease

They found that in more religiously diverse (and more disease-ridden) places people move shorter distances than in healthier, religiously monotonous societies.

ECONOMIST: Religious diversity may be caused by disease

When they have been, the correlation between the number of religions in a place and how disease-ridden it is looks impressive.

ECONOMIST: Religious diversity may be caused by disease