it's a full moon tonight and the crazies are out

Ivan Kelly, James Rotton and Roger Culver (1996) examined over 100 studies on lunar effects and concluded that the studies have failed to show a reliable and significant correlation (i.e., one not likely due to chance) between the full moon, or any other phase of the moon, and each of the following:

-the homicide rate
-traffic accidents
-crisis calls to police or fire stations
-domestic violence
-births of babies
-suicide
-major disasters
-casino payout rates
-assassinations
-kidnappings
-aggression by professional hockey players
-violence in prisons
-psychiatric admissions [one study found admissions were lowest during a full moon]
-agitated behavior by nursing home residents
-assaults
-gunshot wounds
-stabbings
-emergency room admissions [but see]
-behavioral outbursts of psychologically challenged rural adults
-lycanthropy
-vampirism
-alcoholism
-sleep walking
-epilepsy

If so many studies have failed to prove a significant correlation between the full moon and anything, why do so many people believe in these lunar myths? Kelly, Rotton, and Culver suspect four factors: media effects, folklore and tradition, misconceptions, and cognitive biases. A fifth factor should be considered, as well: communal reinforcement.