Beyond regional influences, brain conditioning may also move an individual out of the mainstream of mild and moderate religiosity into atheism or zealotry.

Newberg and other researchers have seen changes, for example, in the brains of those who meditate or pray frequently. Imaging studies have revealed that the brain’s frontal lobes, which are activated during prayer, increase in activity and thickness in people. The thalamus, a key relay that integrates sensory information, also showed changes in people who prayed for as little as 12 minutes a day for two months, Newberg explained.

“There’s this saying, ‘the neurons that fire together wire together,'” said Newberg. “The more you believe in it, the more that belief becomes your reality.”

For both non-religious and religious people, then, reinforcement of a set of beliefs modifies the brain to accept information supportive of that system and reject information that goes against it.

Inherent brain biology as determined by genetics could play a role, too. Some findings: A proposed “god gene” could predispose gene carriers to transcendental experiences, while those people with a more prominent brain fold called the paracingulate sulcus might be better able to separate real events from imagination.