War and religion — name a more iconic duo.

Image credits: David Ilff / Wikipedia (CC-BY-SA 3.0).

Over the centuries, countless wars have been fought over religion. From Ancient times and up until the very current day, religion has often been a spark for war. But does it go the other way around too? In other words, can war make people more religious? In a new study, an international team of researchers analyzed this possibility, finding a strong connection between the two.

“Why would war increase religiosity? Here, we consider two interrelated sets of hypotheses derived from cultural evolutionary theory. First, both theory and evidence suggest that external threats cause people to adhere more tightly to social norms, including their religious beliefs and practices,” researchers write. As for the second hypothesis, “religions may have culturally evolved to specifically exploit the psychological states created by uncertainty and existential threats as a means to more effectively disseminate themselves.”

There’s even another reason why war could induce increased religiousness: the belief in gods goes hand in hand with some idea of divine protection and afterlife, which can help individuals operate in existential uncertainty and extreme danger. But whether or not this was really the case remained unclear until now.

In order to get to the bottom of things, researchers analyzed survey data from 1,709 individuals in three post-conflict societies: Uganda, Sierra Leone, and Tajikistan. The unfortunate environment of these countries makes them suitable for this type of study, and the fact that they were in different geographical areas and come from different cultures also give an extra degree of robustness to the results.

The nature and intensity of the conflicts in these countries varied substantially. However, regardless of these factors, there did seem to be a connection between war and religiosity: across all three sites, those more exposed to war were more likely to be members of religious groups and attend rituals. Even years after the conflict had ceased, people who were more affected by the war were more likely to participate in religious groups — both Christian and Muslim. The results hold even when researchers compared only individuals from the same community, ethnic group, and religion.

In other words, it doesn’t look like there’s any external factor responsible for this. It’s still a correlation and not a causation, but it there are good reasons to believe that there is a cause-effect relationship at play.

This could have important consequences. If war makes people more religious, and if religion makes people more war-prone, we have the recipe for a devastating feedback loop — which could help to at least partially explain some of the current situations in modern-day war areas.

“In conclusion, our results suggest that the experience of war-related violence increases religious engagement and ritual participation. The potential existence of these relationships has important theoretical, political and social implications,” researchers conclude.

The study “War increases religiosity” by Henrich et al. has been published in Nature Behavior.