Climate predicts religious beliefs

What do religion and the environment have in common? In the biggest study of its kind, where people live has predicted what they believe...

People living places where the climate is harsh, like around the Saharan desert, tend to believe in so-called moralising high gods - gods who created the Earth and care about how humans treat each other. But why do we see this pattern?

"It has long been theorised that religions tend to function as a kind of social glue that bonds people together. One prominent theory is that beliefs in the moralising Gods function to support efficient and reliable cooperative exchange, a kind of social glue," explained Joseph Bulbulia, a religious scholar working on this study. 

But the social glue hypothesis came to Carlos Botero in his own way. He was working at the National Evolutionary Synthesis Center (NESCent), a multidisciplinary group studying the evolution of human culture, when he happened upon a dataset about the societies around the world worshipping moralising high gods. 

When he plotted this data on the world map, he noticed where these peoples lived there were also many bird species that cooperated for breeding by helping unrelated young survive. Pondering this surprising correlation led him to the social glue hypothesis, and he found many studies linking religion to cooperation in humans.

The NESCent research group pooled their resources under his lead to compile one of the world's richest datasets, the Ethnographic Atlas. This combines information about the cultures of 583 societies with brand new high-resolution climate data. The data was good enough that they could weed out the biggest confounding causes in this type of research: shared cultural ancestry and the spread of beliefs between nearby peoples during war and trade.

The factors they found that determined who would worship moralising high gods were the harshness and unpredictability of the environment, the practice of animal husbandry and farming, having a complex political hierarchy, and recognising ownership of 'moveable' property like animals. In the end, their model could predict which societies would believe in these gods with 91% accuracy - miles better than usual 'good' social science predictions with 75% accuracy. 

"Our results therefore support the idea that moralising religions may have played a central role in supporting cooperation at a societal level around the world. The first systematic global test for the social glue hypothesis supports its predictions," says Bulbulia.  

But the study is more important than just its results. It is a blueprint for how scientists from different fields can work with the new big datasets available to investigate basic, yet poorly understood, questions about humans and religion. 

"Embracing understanding is something that is a worthwhile pursuit," says Botero. "I don't see why some of the aspects of religious belief would not be amenable to this. This study shows how science and religion can actually explore joint interests without any animosity."