Bicameralism

"In psychology, bicameralism is a hypothesis which argues that the human brain once assumed a state known as a bicameral mind in which cognitive functions are divided between one part of the brain which appears to be "speaking", and a second part which listens and obeys." The Almight Wikipedia

perhaps my notion of sensing 'god' in the past is little more than an advancement of the sense/voice of the 'other' in my mind. Here's how this might work: there's has been selection pressure in human evolution to give sexual selection favoritism to those that can easily and adeptly communicate. Part of learning how to do this in an advanced manner very well may have developed from a mental ability to model/practice having conversations in our minds. Think of your own experience. Haven't you on some level experienced a sense of both speaking to another (who is yourself, but a different yourself...) as well as hearing our 'conscience'/Jiminy Cricket which 'speaks' to us from within and without...IT's hard to describe without sounding like a stark raving lunatic, but perhaps you will with very little effort understand what I'm saying.  We have a built in "other" inside ourselves--a speech modeling simulator that allows us to have internal dialog with ourselves. This ability may have been valuable to allows us to train to be able to fluently communicate ideas. Perhaps a side effect of this isn't in fact that far off from our sense of 'the other' in spirituality both as a soul and as the presence of a deity.
Much more could be said about how we needed to be able to understand another beings mind, which is a very advanced form of cognition and primatologist debate on how well other primates can do it.  No question that we do it so well that we give inanimate objects animation, personification, identities, names and imagine they have a mind.  Ever gotten angry at a machine/computer?  Then you're guilty. :)