Have a look at Explanatory Theories of Religion ( http://genealogyreligion.net/explanatory-theories-of-religion ). I found that article on Cris Campbell's blog.
There are many explanatory and evolutionary theories of how magical and religious thoughts (and different religions) emerged among our ancestors.
In this reblogged article we can read about Cris Campbell's take on that topic.
Cris holds advanced degrees in anthropology, philosophy, and law. He's apparently very interested in the origin of magical and religious thoughts. And he obviously knows a lot - and I really mean a great deal; he's a scholar! - about the many hypotheses and theories that try to explain how it became possible for our ancestors to invent divine spiritual beings of different kinds.
His blog readers get a very good resume of how this "religification process" may have looked like. Here are some quotes taken from Cris Campbell's blog article:
This is not, of course, a simple question and no single theory provides a definitive answer. Since 1990 (i.e., the beginning of the modern era of evolutionary theorizing about religion), scholars have proposed so many different varieties of “cognitive byproduct” and “social adaptive” theories that simply surveying, sorting, and analyzing them is a considerable challenge. Synthesizing them is an even greater challenge and, given their differing premises, may be impossible.
[...]
Seeking clarity, last year I decided to conduct an intensive review of all previous theories (i.e., those predating 1990) that could variously be characterized as: (1) explanatory, (2) developmental, and/or (3) evolutionary. The latter category can be confusing because many scholars working within a post-Darwinian evolutionary paradigm tend to conflate biological withcultural evolution. Such scholars may also prefer non-Darwinian explanations, but they are still working within an evolutionary or developmental paradigm. When this occurs, I refer to them as “evolutionist.”
My richly rewarding review resulted in a great deal of writing, most of which has appeared here in scattered posts over the past year. Now that the review is nearly finished, I want to gather all those posts and links on a single page. The theorists are listed mostly in chronological order of their appearance. I chose this arrangement not just for convenience. One thing I discovered is that the scholars working within the developmental-evolutionist tradition were fully aware of previous work and were responding to their predecessors or contemporaries. If you read these scholars’ original works in serial order, you will find yourself eavesdropping on a brilliant conversation that lasted for well over 100 years.
BTW, here's an interesting TED Talk video: https://www.youtube.com/watch?v=c7vH4rgdmxw .
The speaker is Yuval Noah Harari, author of the book "Sapiens: A Brief History of Humankind". For a short review of that book, have a look at http://www.theguardian.com/books/2014/sep/21/sapiens-brief-history-mankind-review-yuval-noah-harari
As an atheist I especially like Harari's take on money and gods. Suggest to a chimp that if he gives me one of his bananas, I'll give him some paper money in return, and the chimp would, maybe, wonder if you've gone insane.
The same thing goes for gods and heavens. If you pay tithes to your church, your priest/minister promises you that he'll do all he can to help you entering Heaven through its Pearly Gates.
A chimp would NEVER buy that concept, that imaginary and creative symbolic idea. (Neither would I, but many religious fellow humans seem to accept that kind of deal without any hesitation at all. How about you?)
