Book excerpt: In 2006, scientist Richard Dawkins published a blockbuster bestseller, The God Delusion. This atheist manifesto sparked a furious reaction from believers, who have responded with numerous books of their own. By pitting science against religion, however, this debate overlooks what science can tell us about religion. According to evolutionary psychologist Matt J. Rossano, what science reveals is that religion made us human. In Supernatural Selection, Rossano presents an evolutionary history of religion. Neither an apologist for religion nor a religion-basher, he draws together evidence from a wide range of disciplines to show the valuable--even essential--adaptive purpose served by systematic belief in the supernatural. The roots of religion stretch as far back as half a million years, when our ancestors developed the motor control to engage in social rituals--that is, to sing and dance together. Then, about 70,000 years ago, a global ecological crisis drove humanity to the edge of extinction. It forced the survivors to create new strategies for survival, and religious rituals were foremost among them. Fundamentally, Rossano writes, religion is a way for humans to relate to each other and the world around them--and, in the grim struggles of prehistory, it offered significant survival and reproductive advantages. It emerged as our ancestors' first health care system, and a critical part of that health care system was social support. Religious groups tended to be far more cohesive, which gave them a competitive advantage over non-religious groups, and enabled them to conquer the globe. Rather than focusing on one aspect of religion, as many theorists do, Rossano offers an all-encompassing approach that is rich with surprises, insights, and provocative conclusions.