In the journal Nature, cognitive scientist Pascal Boyer (author of Religion Explained) has an essay about why “atheism will always be a harder sell than religion.” This argument is common among many scientists studying religion:
One important finding is that people are only aware of some of their religious ideas. True, they can describe their beliefs, such as that there is an omnipotent God who created the world, or that spirits are hiding in the forest. But cognitive psychology shows that explicitly accessible beliefs of this sort are always accompanied by a host of tacit assumptions that are generally not available to conscious inspection.
Continue reading in Nature. Anthropologist Scott Atran also makes a similar case in the last chapter of his In Gods We Trust.