In the June 23, 2011 issue of Nature (available online only to subscribers), A. C. Grayling reviews Michael Shermer's new book, The Believing Brain (2011). He notes Shermer's double-barreled explanation for why humans are so ready and willing to believe things that aren't true:

One is the brain's readiness to perceive patterns even in random phenomena. The other is its readiness to nominate agency--intentional action--as the cause of natural events. Both explain belief-formation in general, not just religious or super naturalistic belief.

I've written about Michael Shermer before at this website, mentioning, as does Grayling, that Shermer "gives the names 'patternicity' and 'agenticity' to the brain's pattern-seeking and agency-attributing propensities . . ." Once these beliefs are somewhat established in one's mind, it's difficult to turn back, due to the confirmation bias, which blinds us to evidence contrary to our beliefs and makes evidence supporting our beliefs extra salient. [caption id="attachment_19088" align="alignright" width="300" caption="Image by Erich Vieth using Dreamstime Image by FourOaks with permission"][/caption] Shermer suggests that there is an evolution-based explanation for this over-eagerness to find patterns and to attribute agency, and it has to do with whether one should act quickly or not to the rustling in the bushes nearby, which might be a tiger. Grayling also points out that the belief in modern religions could not possibly be a hardwired phenomenon given that these "God-believing religions are very young in historical terms; they seem to have developed after and perhaps because of agriculture and associated settled urban life, and are therefore less than 10,000 years old."   There is thus no evidence for a "God-gene."