according to the article, religions probably appeared as humans evolved the ability to handle complicated social interactions during the past 60,000 years or so. however, most evidence of religious behavior only dates back about 10,000 years, raising questions about why humans didn't become religious sooner... maybe because there were smaller groups wandering around that didn't need any external pressure to enjoy life as it was.
without religion, the article reads, "large scale cooperation, which now spans the world, would be impossible. religion can help foster cooperation because it ensures that people share the same set of rules about behavior, and think they'll be punished if they don't follow them. religion also unites people, especially in times of great uncertainty."that last paragraph made me think... are we the only species that cooperate and has rules on behaviour? i don't think so. we might be the only species who believes in punishment from a superior being for being disobedient, though. but cooperation comes naturally to many species and maybe religion is just a byproduct of it, not the other way around.