@ Ankou - In your post, you state " it is interesting that the increase in religion within human evolution and development has coincided with the reduction in brain size."
Did you mean to say that? It is my understanding that brain size has increased with evolution, regardless of the religiousness or otherwise :)
The other points you made - are you talking about memes?
@ Jake - I think that as newborns and in early years, the default state of religiousity within an individual is atheist. But, as a species, we are hardwired for a narrative view of the universe, and we gain that narrative view through mimicry and adoption of a worldview. Most of that information inevitably will come from the parents.
Brainwashing is perhaps a perjorative term ,but, as a species, it is undeniable that much of those early beliefs and experiences occur through mimicry and imprinting.
Various studies i have read, and indeed my own experience, have emphasized the point that for many people, religiousness was passed on from the parent - and proves remarkably resistant to critical and sceptical analysis.