No, the belief in gods has been around much longer than the belief of no gods. I would tend to think it is the default human position, and just plain ole human nature.
I would like to see that documented.
I see it as more likely that as mankind evolved from ape-like ancestors that superstition developing out of a hope of controlling seemingly uncontrollable forces. Lightning, lack of game or rainfall, attacks by predatory animals are all forces that threatened early humans and semi-humans. Can't you see that some developed the "ability" to intercede for mankind with these forces? "If we perform the correct ritual, the tigers will leave us alone. I know the ritual, and (for the right fee) can perform it for you." Thus was born the shaman.
The promise of life after death was just an outgrowth of that principle: "Pay me now for a promise of everlasting life later."
Robert A. Heinlein writes:
The profession of shaman has many advantages. It offers high status with a safe livelihood free of work in the dreary, sweaty sense. In most societies it offers legal privileges and immunities not granted to other men. But it is hard to see how a man who has been given a mandate from on High to spread tidings of joy to all mankind can be seriously interested in taking up a collection to pay his salary; it causes one to suspect that the shaman is on the moral level of any other con man. But it is a lovely work if you can stomach it.
Robert A. Heinlein,
Time Enough for Love, 1973
Religious belief does not constitute scientific evidence, nor does it convey scientific knowledge.