Religious belief is very common in Homo sapiens, with almost all cultures having some kind of supernatural belief that is important to their sense of identity, although that’s about the only unifying characteristic of these ideas. Within the spectrum of human society is a similarly broad spectrum of religious beliefs. These range from the simple “animal spirits” who are responsible for the unexplained (but not much else) to a “High” or “King” God who takes an active role in the world, dictating morals of a people he created.

Given the prevalence and importance of these religious ideas studying them is obviously something which greatly interests many evolutionary anthropologists. This interest is further amplified by the fact it is one of the behaviours which is most distinct from the animal kingdom, with few precedents found even in our closest relatives. Unfortunately, whilst we do have a decent understanding of when religious ideas arose, the hows and whys of their appearance are still unknown.

However, anthropologists have managed to identify certain factors which seem to be associated with the rise of complex religious beliefs (such as the “high” god). Notably, social and economic complexity. For example, animal sacrifice and altars in the Near East are consistently preceded by groups acquiring surplus food (and the economic and social changes associated with such an acquisition). However, not much has been figured out beyond that. Increasing social complexity is correlated with more complex religious ideas, but why?

A myriad of potential causal relationships have been proposed to fill this gap. Complex “high” god ideas could’ve be a way to try and stop free-riders exploiting the work of the group. “Don’t co-operate and God will get you.” Alternatively it could’ve been a method used by a few individuals to cement their power. “God says you should make me your leader.” Now, I (nor the researchers) am not not trying to imply that a god concept was invented by self serving individuals. Rather, it arose and spread organically but this spread was driven by some benefit it conferred in much the same way a beneficial gene might spread throughout the population. Its not even necessarily beneficial, neutral genes can spread too!

In an effort to identify which of these competing ideas was correct two anthropologists decided to do some science. They favoured the hypothesis that the “high” god concept was fostered because it helped strong co-operative bonds develop. This co-operation was necessary for large complex societies and/or those dependent on resource which required extensive co-operative effort. So they predicted that “high” gods would be more prevalent in larger cultures and amongst farming communities (since farming requires a lot of people to work together). They also expected that pastoralists (those who live off a herd of animals they own) would not fit on this trend. Although typically small in number, maintaining a herd requires a lot of work by the entire group.

So they went out and gathered data (albeit from other researchers) on 178 different cultures, comparing their source of food, group size, social complexity and type of religious belief. When analysed this information almost exactly matched their predictions. Amongst foragers – who can easily gather enough food with minimal co-operation between individuals – 88% had either no “high” god or a “high” god which did not bestow morals and did not interact with the world. At the other extreme of the scale, ~40% of groups dependent on intensive agriculture had a “high” god who interfered with the world and gave morals to the group.

Similarly the data on group size and type of god also matched their predictions. 95% of groups with <1,000 individuals lacked a “high” god whilst ~43% of groups with >10,000 members did have a moral giving “high” god. Curiously the percentage does not increase further after that. Belief in a “high” god is no more prevalent in a group with >100,000 members than it is in a group with 10,000 – 99,999 members. This suggests that the threshold at which ideas which maintain co-operation – such as a “high” god – is between 10,000 – 99,999 members.

Social complexity data once again fits with these predictions. 80% of egalitarian groups lack the “high” god whilst 40% of groups with either a class system or wealth distinctions (i.e. someone being richer than others) had a “high” god. Pastoralism, again, fits right in with what was expected. The more one depends on animal husbandry the more one has to work together and also the more likely one is to have a “high” god. Indeed, this trend was so powerful that cultures entirely dependent on animal husbandry had a higher rate of “high” god belief than either the largest or most complex societies of other sorts.

All in all this research provides a compelling and well substantiated explanation for the prevalence of “high” gods. As co-operation became more and more important to survival the beliefs which fostered this co-operation also became more and more important and as a result more and more common. Be it a resource that requires a communal effort to gather or a large society which is difficult to manage, situations which demanded co-operation demanded beliefs to bolster this behaviour. This information can provide key insights into the past. For example, we find evidence of a prehistoric tribe performing a ritual but estimates indicate the tribe had <999 members then we know the odds of that ritual involving a “high” god are very small.

That said the picture is still not complete. For example, farming is typically responsible for population growth and so it could only be linked with a “high” god because it is also linked with large populations. Disentangling all these threads will require more work. So the researchers suggest that further research be undertaken to find more information on the ultimate cause of belief in a “high” god, along with working out how some societies can survive without it. How can co-operation be fostered without a binding religious belief?

This is a question that will not only help us understand society but is very key to our future. Co-operation will likely remain the foundation of civilisation but a “high” god may not. Secularity is rising in many countries – arguably for good reason – but we mustn’t forget that religion once played a key role in many societies. We must be sure that we do not loose the glue which binds us together and be sure to develop secular ways of ensuring humanity continues to work together.

Human nature (Hawthorne, N.Y.) PMID: Peoples HC, & Marlowe FW (2012). Subsistence and the Evolution of Religion.PMID: 22837060

On a somewhat self-congratulatory note, this is my 100th post on this blog!