Humans more likely to believe in powerful and judgmental gods during times of hardship and extremes of weather

Plagues, floods and famines often play a central role in religious stories. Research suggests they may have also helped start the belief in some gods in the first place.

A study of 583 religious societies around the world has concluded that humans are more likely to believe in powerful and judgmental gods during times of hardship and extremes of weather. The research may help to shed light on how religions such as Christianity, Judaism and Islam first emerged.

It suggests that believing in a high god, where followers are required to live by certain moral rules, helped to unite communities in harsh environments and when food was scarce.

Dr Carlos Botero, a biologist at North Carolina State University, who led the work, said the harsher the conditions, the more likely was belief in a powerful deity. “Environmental duress and environmental uncertainty can make life very difficult and there is pretty good evidence that these conditions tend to promote sociality in non-human animals, because group living can help individuals thrive when conditions are good and survive when they suddenly turn bad,” Botero said.

“We believe that similar reasons may explain the links between this particular aspect of religious beliefs and resource scarcity or environmental uncertainty. Among humans, there is also good evidence that religious beliefs may help shape social behaviour by, for example, promoting cooperation, fairness and honesty.”

The study, published in the journal Proceedings of the National Academy of Sciences, used historical, social and ecological data from between 1900 and 1960 for 583 traditional societies with religious beliefs around the world. These included common religions like Christianity and Islam along with rarer religions such as Zahv, the belief system of the Akha people in south-east Asia.

The researchers used detailed climate, rainfall and plant growth data for each area to build up a picture of who religious belief compared to the ecological conditions each society was living in. Overall they found the belief structures were driven by a complex combination of social, ecological and historical factors.

The emergence of religion has long been explained as a result of either culture or environmental factors but not both. But the researchers found that food scarcity and climate instability were particularly strongly associated with belief in high gods that enforced a moral code. This might help to explain why religions such as Christianity and Islam emerged in parts of the world that have suffered extreme climatic changes and where famine was rife.

Some scholars have claimed that dramatic changes in the climate around 535 AD have been linked to the rise of Islam and its expansion around the world.

The researchers behind the latest study warn against oversimplifying the spread of religions and said they hope to investigate how trade, conquest and spread of language also played a role.

Professor Russell Gray, a psychologist at the University of Auckland and a founding director of the Max Planck Institute for History and the Sciences in Jena, Germany, who also took part in the study, said it was clear that adversity played a key role in whether people believe in certain types of god.

“When life is tough or when it’s uncertain, people believe in big gods,” he said. “Pro-social behaviour maybe helps people do well in harsh or unpredictable environments.”