So, just as culture evolved, language evolved and technology evolved, I believe that that human religious imagination evolved. So, Steve, part of what we're doing here is trying to think about behavior and think about evolution and sort of how they can play off of each other, and I know that the field of evolution in psychology is dedicated to trying to make those kinds of connections precise. Can you just give us a sense of what evolutionary psychology actually does and how it can give insight into these kinds of issues?