Pretend you’re an alien anthropologist come to Earth to study humans. What do you notice most about these strange, bipedal creatures? Their glittering cities? Their fondness for chocolate? Their use of daringly creative insults during traffic jams? Maybe, but let’s not forget one behavior that distinguishes humans almost more than anything else: ritual, and lots of it. No other animal participates in, invents, or performs rituals as complex and detailed as humans. But why? Our bemused alien anthropologist might benefit from new Danish research describing how ritual, using what’s called “cognitive resource depletion,” helps cultures pass knowledge and values down to new members.