CSICOP's Library & Research Center

Surveys have revealed that roughly half of the population in the U.S. believes that the moon has an influence on human behavior. In 1978, Arnold Lieber, a psychiatrist, labeled this influence the “lunar effect”. Popular folklore and the media often reinforce this belief. News stories, novels and movies can promote the connection between a full moon and odd incidents. However, science does not support it. Scientific equations show us why the moon causes tidal changes in oceans. But, there essentially no tidal effects in smaller, enclosed bodies of water such as lakes, ponds or the human body (of which water is a significant portion).
After many decades of controlled medical studies for all sorts of behavior, hormones, emotion, etc., patterns directly relating to lunar cycles have not been found. Specific studies investigating moon phases versus crime, birth rates, sleepwalking, violence or disasters have either found no relationship or have serious shortcomings. In the 1980’s skeptical investigators who analyzed the studies that did show a link, revealed that reports of lunar effect contained inappropriate, misleading or erroneous statistics, inappropriate use of data or test procedures or improper controls. The “positive” studies are even inconsistent with each other as to which phase of the moon is most influential.
Unfortunately, many people consider very unreliable folktales as accurate information. But, widespread belief in something does not mean it actually exists. People are more likely to notice things that support their belief and ignore that which does not. Plus, people tend to hold tight to certain ideas, ignoring the logic and evidence that contradicts them. Thus, it looks like the lunar effect will be slower to wane than the full moon itself.
- Sharon Hill (Scientist)
CSICOP Resources
Skeptical Inquirer Online Articles

How the Moon Affects You (book review)


Skeptical Briefs Online Articles
Skeptiseum Online Exhibits
Other Online Resources
Serendip:   Full Moon Madness: The Search for a Relationship between the Mind and Lunar Cycles
Neuroscience for Kids:   Moonstruck! Does The Full Moon Influence Behavior?
The Straight Dope:   Do Things Get Crazy When the Moon is Full
NOVA:   Lunar Puzzlers
Museum of Hoaxes:   The Great Moon Hoax
Pro-Paranormal Online Resources
One Giant Leap:The Allure of the Moon - A Wet, Howling Mouthful of Moon

Young Skeptics Topic Database
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