Here is a long, but fascinating, article that addresses God-belief and evolution. The article concludes as following:
At first blush, Barrett's faith might seem confusing. How does his view of God as a byproduct of our mental architecture coexist with his Christianity? Why doesn't the byproduct theory turn him into a skeptic?
"Christian theology teaches that people were crafted by God to be in a loving relationship with him and other people," Barrett wrote in his e-mail message. "Why wouldn't God, then, design us in such a way as to find belief in divinity quite natural?" Having a scientific explanation for mental phenomena does not mean we should stop believing in them, he wrote. "Suppose science produces a convincing account for why I think my wife loves me "” should I then stop believing that she does?"
What can be made of atheists, then? If the evolutionary view of religion is true, they have to work hard at being atheists, to resist slipping into intrinsic habits of mind that make it easier to believe than not to believe. Atran says he faces an emotional and intellectual struggle to live without God in a nonatheist world, and he suspects that is where his little superstitions come from, his passing thought about crossing his fingers during turbulence or knocking on wood just in case. It is like an atavistic theism erupting when his guard is down. The comforts and consolations of belief are alluring even to him, he says, and probably will become more so as he gets closer to the end of his life. He fights it because he is a scientist and holds the values of rationalism higher than the values of spiritualism.
This internal push and pull between the spiritual and the rational reflects what used to be called the "God of the gaps" view of religion. The presumption was that as science was able to answer more questions about the natural world, God would be invoked to answer fewer, and religion would eventually recede. Research about the evolution of religion suggests otherwise. No matter how much science can explain, it seems, the real gap that God fills is an emptiness that our big-brained mental architecture interprets as a yearning for the supernatural. The drive to satisfy that yearning, according to both adaptationists and byproduct theorists, might be an inevitable and eternal part of what Atran calls the tragedy of human cognition.