85 Behavior and the Moon

Based on research by James Rotton and I.W. Kelly, 1985. Psychology Science Minute written by Juanita N. Baker, Ph.D..

Why are humans susceptible to erroneous conclusions?   Reasonable sounding statements can mislead us. Being aware of this common error can help us think more critically.

Every month, we see the beauty of the full moon, markedly changing our night sky. Since its gravitational pull is strong enough to influence ocean tides, it seems “reasonable” that there could be a lunar effect influencing human or other animal behavior.  James Rotton, Florida International University, and Ivan Kelly, University of Saskatchewan, reviewed many published studies that have examined whether the full moon was associated with birth rate, mental hospital admissions, psychiatric disturbances, suicide, crisis calls, homicide, or other criminal offenses. They found no overall significant association between the full moon and any of these events when compared to non full moon days.

Since the full moon is so noticeable, emergency personnel and the public may take note when something major happens at the same time.  Yet, when these same events occur the other 25 days of the month, they do not notice this lack of association.  Thus illusionary correlations can lead to myths.

Next time someone states something amazing, stop and think, “Yes, it sounds plausible, but what is the scientific evidence?”


Kelly, Ivan; Rotton, James; Culver, Roger (1986), “The Moon Was Full and Nothing Happened: A Review of Studies on the Moon and Human Behavior,” Skeptical Inquirer, 10 (2): 129–43.

Martens, R.; Kelly, I. W.; Saklofske, D. H. (1988). “Lunar Phase and Birthrate: A 50-year Critical Review.” Psychological Reports 63 (3): 923–934. doi:10.2466/pr0.1988.63.3.923. ISSN 0033-2941.

Rotton, J., & Kelly, I. W. (1985). Much ado about the full moon: A meta-analysis of lunar-lunacy research. Psychological Bulletin, 97(2), 286-306. doi:10.1037/0033-2909.97.2.286

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