Evolutionary explanations for religious beliefs?

From a Scientific American posting, Is Religion Adaptive? It's Complicated - A group of Darwinian theorists discuss religion in Edinburgh, Scotland, by Jesse Bering of Queens University, Belfast (links are in original):

... [T]he past decade has seen tremendous and quite rapid developments in the naturalistic study of religion. Topics such as God, souls and sin are no longer being treated as “outside science” but rather as biologically based emanations of the evolved human mind, subject to psychological scrutiny like any other aspect of human nature.  ...

Here is the fly-on-the-wall’s view of just a few of the topics discussed last weekend: [¶¶]

Political scientist and evolutionary biologist Dominic Johnson from the University of Edinburgh presented his argument that the idea of omniscient supernatural agents served an adaptive social policing function in the ancestral past. Johnson reasons that this would have encouraged individuals in groups to conform to group sanctions out of the fear of divine punishment, thus lessening the chances of social fission. This phenomenon would have been biologically adaptive since larger groups meant better chances of survival and reproductive success for individual members. It’s a bit like Santa Claus knowing whether we’re bad or good (but Santa doesn’t cause you to suffer renal failure, kill your crops, or sentence you to everlasting torment).

Anthropologist Richard Sosis summarized his “costly signaling” hypothesis of religious behavior. The gist of Sosis’s clever theory is that people engage in all sorts of costly religious behaviors—wasting time on rituals, wearing uncomfortable clothes, spending their hard-earned money—because, in doing so, they are advertising their commitment to the religious in-group. In other words, if you’re willing to do things such as cut off your child’s foreskin, pay a regular alms tax of 2.5 percent of your net worth or sit twiddling your thumbs for two hours every Sunday morning on a hard church pew, then your fellow believers will assume that you’re really one of them and can therefore be trusted.

Evolutionary biologist Robert Trivers from Rutgers University, meanwhile, discussed the possible role of psychological self-deception in the realm of religion and reviewed the impossible to ignore evidence that religiosity positively effects human health. ...