Across the centuries, many a person has uttered the phrase “There must be a full moon out there” in an attempt to explain weird happenings at night. Indeed, the Roman goddess of the moon bore a name that remains familiar to us today: Luna, prefix of the word “lunatic.” Greek philosopher Aristotle and Roman historian Pliny the Elder suggested that the brain was the “moistest” organ in the body and thereby most susceptible to the pernicious influences of the moon, which triggers the tides. Belief in the “lunar lunacy effect,” or “Transylvania effect,” as it is sometimes called, persisted in Europe through the Middle Ages, when humans were widely reputed to transmogrify into werewolves or vampires during a full moon.

Even today many people think the mystical powers of the full moon induce erratic behaviors, psychiatric hospital admissions, suicides, homicides, emergency room calls, traffic accidents, fights at professional hockey games, dog bites and all manner of strange events. One survey revealed that 45 percent of college students believe moonstruck humans are prone to unusual behaviors, and other surveys suggest that mental health professionals may be still more likely than laypeople to hold this conviction. In 2007 several police departments in the U.K. even added officers on full-moon nights in an effort to cope with presumed higher crime rates.