Embedded Player If you've taken part in a religious service, have you ever stopped to think about how it all came to be? How did people become believers? Where did the rituals come from? And most of all, what purpose does it all serve? This week, we explore these questions with psychologist Azim Shariff, who argues that we can think of religion from a Darwinian perspective, as an innovation that helped human societies to survive and flourish.