A recent podcast by the German radio station Deutschlandfunk on the new science of geomythology reminded me of how important and adaptive religion must have been for early humans (related article in The Guardian). Geomythology refers to the search for natural catastrophes at the origin of ancient myths. The podcast mentioned a vulcanic eruption which coincided with the appearance of a myth about a god of the underworld, Llao, living undernath a in a fiery mountain in a Native American tribe. They also talk about a lake-god punishing greedy people in Afrika (near three volcanic crater lakes in Cameroon and Rwanda) with white smoke from a lake running down the valleys and killing everything in its path. This myth was related to carbon dioxide emanating as white smoke from the crater lakes (this PBS article explains more about these lakes and what is done today to prevent these catastrophes from occuring). I found one story particularly amusing (and telling). In Italy in the fifth century AD, a legend tells of an earthquake and flames in the air and all that. When the scared people ran to the local bishop, he told them that the archangel Michael had appeared to him and demanded a church to be built (how convenient for the bishop!) in a cave under Mount Tumba (now Monte Sant' Angelo). When geologists now examined the area, they found an acive site right underneath the mountain.
All these stories share an unpredictable catastrophe and a supernatural explanation, the understanding of which will prevent further catastrophe from happening. In most cases, there is some god which needs to be pleased by good ebhavior in order to prevent death. In other words, priests, shamans and other religious leaders have used unpredictable death and destruction very early on to police the behavior of their populace. The origins of such religiosity are easy enough to spot. There are probably a number of factors, but I'll focus on what I find are the most important three. The first one is that we cannot think outside of causality. Everything needs to have a cause, even things where we cannot find a cause. The demand for causes is so strong that we invent them if we can't find them. Deriving from that is our uncanny ability to construct what is called a theory of mind. We infer other's intentions from their actions, facial expressions and the like. It is well studied that this search for intentions is so strong that we even attribute intentions and emotions to inanimate objects. So the myths explain an unpredictable event with intentions of supernatural beings. This all makes a lot of sense. After all, this is what we evolved to do: being smarter than our competitors and knowing what they're up to. The third and final point is what rounds the story off, though. Almost all of these myths contain some sort of moral imperative: if you behave, these bad things won't happen to you. They express our strong desire to be able to control our fate, to know what is going to happen to us and to be able to behave in a certain way to make sure everything will be fine. Much as a rain-dance is performed to stop the draught or a prayer to cure cancer or going to church to be elected US president, these myths are part of a psychological crutch that developed in order to keep people from developing "learned helplessness" in the face of uncontrollable events (i.e., depression). Maybe not surprisingly, religious people are less likely to develop symptoms of depression.
This is all not new, and several other people have also recognized these mechanisms. But the geomythology added a somewhat new and even more general angle to the whole "religiosiy as an operant" story, so I thought it was ok to repeat myself a little.