A new study claims that religion may have helped prevent the spread of disease among ancient humans by dividing people and reducing the likelihood that they'd pass infections to one another. When religious beliefs kept one group apart from its neighbors, the theory goes, members of the group were less likely to pick up new diseases and, generation after generation, the group's genetic makeup would change.
The scientists, Corey Fincher and Randy Thornhill of the University of New Mexico, Albuquerque, believe their study explains the genesis of religious diversity—namely, why countries with hotter climates, where disease is more common, have a greater number of different religions than do countries with cooler climates. "Why does Cote d'Ivoire have 76 religions while Norway has 13, and why does Brazil have 159 religions while Canada has 15 even though in both comparisons the countries are similar in size?" the scientists ask.
What they found is that "religion diversity is the highest where disease diversity is also the highest and the lowest where disease diversity is also the lowest," they say in their report.
"Our analysis suggests that the nature of religion needs to be reconsidered," the researchers conclude. Although religion apparently is for establishing a social marker of group alliance and allegiance, at the most fundamental level, it may be for the avoidance and management of infectious disease."
The study appears in the Proceedings of the Royal Society, Biological Sciences. —Heather Wax