Religion, many commentators have complained, is frustratingly multifaceted. It can give profound meaning to life but, at the same time, pit rival human groups against each other. It can inspire hope for a better life and hatred for outsiders simultaneously. So why the seeming dark and light side of religion? Specifically, why do religions create sharp, often hostile divisions between groups? One research team from the University of New Mexico has found evidence that may surprise you. Hint: it has to do with creepy-crawlies.