Why does having a superior religion provide an edge over atheists? As I asked, what about wars between people of the same religion?
What kind of religious evidence would neanderthals provide?
The old saying "There are no atheists in foxholes" sums it up. Atheists are more likely to crack under pressure while religious people have an extra optimism, confidence, bravery, focus, solidarity, and are more willing to die to save their tribe. Religion also acts as a conduit for passing on culture and knowledge.
Religious artifacts and burying their dead a certain way such as pointing East or West with items for an afterlife are evidence of religion. The Cro-Magnons did this. There is little evidence the Neanderthals did.
Just about every non-cosmetic human trait can be traced to an advantage in tribal warfare. Walking on two legs isn't an advantage. Being able to carry weapons and having lubricated armpits that respond to stress is. From a human evolutionary perspective, religion is simply another trait selected for on the battlefield.