The belief that there is a connection between the moon and madness is widespread, the word 'lunatic' being derived from the latin luna, the moon. That such a connection is believed evident can be seen from the Lunacy Act of 1942, which defined a lunatic as "a demented person enjoying lucid intervals during the first two phases of the moon and 'afflicted' with a period of fatuity in the period following after the full moon."

Although almost 400,000 kilometres away the moon exerts a tremendous influence on both the land masses and the oceans, the obvious inference being that our bodies, and in particular the semi-liquid mass of the brain, could also be subject to such a force. The moon's periodicity seems to epitomize the cyclic rhythms we find both in the cosmos and in the physical world around us. Those who have studied the physiological life of women point to the link between the cycle of human ovulation and its approximation with the lunar cycle. The moon is also said to serve as a trigger for biological clocks in flatworms, plants, and even the sexual inclinations of oysters.

Observations made by those who deal with large numbers of people, record an increase in unusual or eccentric behaviour, and police report an increase in all forms of crime at the time of a full moon, in particular, crimes of violence. Traffic accidents too, are alleged to become more frequent, and doctors and nurses in mental hospitals testify to an increased restiveness among their patients at the time of the full moon. Even some psychiatrists have subscribed privately to the notion of 'moon-madness'.

Scientific studies also seem to confirm the probability of adverse lunar influence on the activities of man. A study of homicides in Dade County, Florida, for example, shows that a disproportionate number of homicides occurred during the 24-hour period before and after the full moon. Another, in 1982, showed that the same disproportionate number of traffic accidents occurred during the night hours of the three day periods of the new moon and the full moon. Others have come to the same conclusion after examining the relationship between the phases of the moon and aggressiveness, and have also reported increased rates of suicide.

It is not considered unreasonable by some to suggest that as our bodies are constituted largely of liquid elements (approximately sixty per cent) and the human brain, being a mass of semi-liquid pulp, that they also could be stirred in some strange way. Many studies have been undertaken, and evidence presented to show that there is an effect, usually in the form of erratic, violent or unusual behaviour, but does the evidence stand up to scrutiny?

The suggestion of similarity between the planet and our bodies fails on two counts: first, only the "surface" of the earth has a 80:20 ratio and gravity involves the attraction of a total mass, not just surface composition. Second, the moon only causes tides in great unbounded bodies of water such as the oceans and even in large land-locked lakes the influence is negligible. In comparison, the water contained in the human body is quite insignificant.

A comparison of other tide-raising objects by which we are surrounded, emphasizes the point even more dramatically. Using the principles of classical mechanics, it can be shown that a mother weighing 55 kg and holding a child at a distance of 15 cms or so, will exert 12 million times more tidal-force on her child than the full moon in whose shadow she stands. When the other large masses by which we are surrounded are taken into consideration, then it can be seen that the effect of the moon is of no concern.

Examination of much of the research which purports to show a correlation between the moon and human behaviour, inevitably discloses bias on the part of the researcher and faulty data analysis. Typical is the inappropriate and misleading statistical procedures in the oft quoted study of homicides in Dade County, Florida, where it was claimed that a disproportionate number of homicides occurred during the twenty-four hour period before and after a full moon. Applying more conventional test procedures however, it was found that homicides were evenly distributed across the phases of the moon.

Another study claimed that a disproportionate number of traffic accidents occurred during the night hours of the three-day periods of the new moon and the full moon. However, it was noted that a large number of these nights fell on weekends, which suggested an alternative correlation that more accidents occur on weekends than on weekdays.

Two examinations of the alleged effects of lunar influence on blood usage and crop germination were carried out by Australian Skeptics in 1991.

In the first, evidence was sought for the increased trauma associated with the Full Moon in the patterns of blood usage at a Sydney Metropolitan Hospital. If, as is claimed, accidents tend to occur more frequently at the Full Moon, then one would expect to see this reflected in the levels of blood usage. Using information supplied by the Hornsby and Kuring-gai Hospital, one of the largest in Sydney, no evidence was found to support the view that increased trauma is associated with any Full Moon effect.

In the second, the Canberra Skeptics analysed a test of the alleged effects of the moon and stars on plant growth. This was prompted by a Canberra Times gardening article and letters to the editor attesting to the veracity of "Moon Planting." Seeds were planted at various times under controlled conditions, and there was no significant difference in germination time or weight of produce when seeds were planted at "good" and "bad" times, according to alleged astrological influences.

The reasons for belief in lunar effects are many – there is the misconception about physical factors as in the tidal-force theory, the media effect which favours occult to rational explanations of phenomena, selective perception where an event is more likely because it supports a belief, and illusory correlation whereby we seek data which supports our beliefs, preconceptions and hypotheses.
 

Bibliography:

Abel, G. and Greenspan, B. 1979. "Human Births and the Phases of the Moon." New England Journal of Medicine. 300:96.
Abel, G. and Singer, B. (Eds.) 1981. Moon Madness. Science and the Paranormal. Charles Scribner's Sons. NY.
Brown, F.A. 1954. "Persistent activity rhythms in the oyster." American Journal of Physiology, 178:510-514.
Campbell, D. and Beets, J. 1978. "Lunacy and the Moon." Psychological Bulletin. 85, 1123-1129.
Happs. John C. 1987, "Belief Systems." the Skeptic. 7(2): 21-26.
Australian Skeptics Inc. PO Box A2324, Sydney South, NSW. 2000. Katzeff, Paul. 1981. Moon Madness. St Edmundsbury Press Ltd., Bury St Edmonds, Suffolk. England.
Leiber, A. 1978. The Lunar Effect: Biological Tides and Human Emotions. Doubleday. Garden City.
Leiber, A. and Sherin, C. 1972. "Homicides and the Lunar Cycle." American Journal of Psychiatry. 129, 69-74.
Oberg, J. "Modern Moon Myths and UFO Folklore." Search Magazine. 5-8, 52-62.
Hines, T. 1988. Pseudoscience and the Paranormal. Prometheus Books. Buffalo, New York.
Meek, Drew. 1991. A Test of Lunar Effects on Crop Germination Times and Yield. theSkeptic. 11(l):13-14.
Smyrk, J. and Fekitoa, R. 1991. Effect of Lunar Phase on Blood Usage in a Sydney Hospital. the Skeptic. 11(l):10-12.
Williams, B. 1991. Full Moon and Empty Heads. the Skeptic. 11(l):8-9. Australian Skeptics Inc.