A current line of research focuses on rituals. People the world over engage in regular collective rituals, where they sing, dance, chant, pray, march together. More puzzling, these activities emerged very early on in our archaeological record. Such activities do cost a lot of energy and have no immediate benefit to individuals and groups that engage in them, yet, we have evidence that early humans engaged in these tasks even while competing with Neanderthals and braving the ice age. What are the possible reasons for this widespread and ancient practice? We test various explanations for these activities, including hypotheses that these activities help us to bond better and that they reduce anxiety. We use a wide range of methods for these studies, including experimental lab studies and ethnographic field experiments.