The Full Moon Causes Strange Behaviour
"The belief that a full moon leads to a measurable rise in crime, accidents, hospital visits, or erratic behaviour."
Decades of research have looked for a real connection between the full moon and crime rates, psychiatric admissions, emergency room visits, births, and more, and the pattern essentially isn't there. Meta-analyses combining results across many individual studies have found full moons to be statistically unrelated to the events people most often blame on them; one dataset even showed a slight dip in homicides during a full moon rather than a rise. There is one small, genuine effect: a 2013 study found people sleep somewhat less deeply around the full moon, roughly 20 minutes less sleep and about 30% less deep sleep, though the effect size is modest. The belief itself persists largely through confirmation bias: an unusual incident on a full-moon night gets remembered and retold, while an ordinary night, full moon or not, doesn't.