Lunar effect
The lunar effect is a purported correlation between specific stages of the roughly 29.5-day
In a number of marine animals, there is stronger evidence for the effects of lunar cycles. Observed effects relating to
Contexts
Claims of a lunar connection have appeared in the following contexts:
Fertility
It is widely believed that the Moon has a relationship with fertility due to the corresponding human menstrual cycle, which averages 28 days.[9][10][11] However, no connection between lunar rhythms and menstrual onset has been conclusively shown to exist, and the similarity in length between the two cycles is most likely coincidental.[12][13]
Birth rate
Multiple studies have found no connection between
Blood loss
It is sometimes claimed that surgeons used to refuse to operate during the full Moon because of the increased risk of death of the patient through blood loss.[23] One team, in Barcelona, Spain, reported a weak correlation between lunar phase and hospital admissions due to gastrointestinal bleeding, but only when comparing full Moon days to all non-full Moon days lumped together.[24] This methodology has been criticized, and the statistical significance of the results disappears if one compares day 29 of the lunar cycle (full Moon) to days 9, 12, 13, or 27 of the lunar cycle, which all have an almost equal number of hospital admissions.[25] The Spanish team acknowledged that the wide variation in the number of admissions throughout the lunar cycle limited the interpretation of the results.[24]
In October 2009, British politician David Tredinnick asserted that during a full Moon "[s]urgeons will not operate because blood clotting is not effective and the police have to put more people on the street.".[26] A spokesman for the Royal College of Surgeons said they would "laugh their heads off" at the suggestion they could not operate on the full Moon.[27]
Human behavior
Epilepsy
A study into epilepsy found a significant negative correlation between the mean number of epileptic seizures per day and the fraction of the Moon that is illuminated, but the effect resulted from the overall brightness of the night, rather than from the moon phase per se.[28]
Law and order
Senior police officers in Brighton, UK, announced in June 2007 that they were planning to deploy more officers over the summer to counter trouble they believe is linked to the lunar cycle.[29] This followed research by the Sussex Police force that concluded there was a rise in violent crime when the Moon was full. A spokeswoman for the police force said "research carried out by us has shown a correlation between violent incidents and full moons". A police officer responsible for the research told the BBC that "From my experience of 19 years of being a police officer, undoubtedly on full moons we do seem to get people with sort of strange behavior – more fractious, argumentative."[30]
Police in Ohio and Kentucky have blamed temporary rises in crime on the full Moon.[31][32][33]
In January 2008, New Zealand's Justice Minister Annette King suggested that a spate of stabbings in the country could have been caused by the lunar cycle.[34]
A reported correlation between Moon phase and the number of homicides in Miami-Dade County was found, through later analysis, not to be supported by the data and to have been the result of inappropriate and misleading statistical procedures.[3]
Motorcycle fatalities
A study of 13,029 motorcyclists killed in nighttime crashes found that there were 5.3% more fatalities on nights with a full moon compared to other nights.[35] The authors speculate that the increase might be due to visual distractions created by the moon, especially when it is near the horizon and appears abruptly between trees, around turns, etc.
Stock market
Several studies have argued that the stock market's average returns are much higher during the half of the month closest to the new moon than the half closest to the full moon. The reasons for this have not been studied, but the authors suggest this may be due to lunar influences on mood.[36][37][38] Another study has found contradictory results and questioned these claims.[39]
Meta-analyses
A meta-analysis of thirty-seven studies that examined relationships between the Moon's four phases and human behavior revealed no significant correlation. The authors found that, of twenty-three studies that had claimed to show correlation, nearly half contained at least one statistical error.[1][3] Similarly, in a review of twenty studies examining correlations between Moon phase and suicides, most of the twenty studies found no correlation, and the ones that did report positive results were inconsistent with each other.[3] A 1978 review of the literature also found that lunar phases and human behavior are not related.[40]
Sleep quality
A 2013 study by Christian Cajochen and collaborators at the University of Basel suggested a correlation between the full Moon and human sleep quality.[41] However, the validity of these results may be limited because of a relatively small (n=33) sample size and inappropriate controls for age and sex.[42] A 2014 study with larger sample sizes (n1=366, n2=29, n3=870) and better experimental controls found no effect of the lunar phase on sleep quality metrics.[42] A 2015 study of 795 children found a three-minute increase in sleep duration near the full moon,[43] but a 2016 study of 5,812 children found a five-minute decrease in sleep duration near the full moon.[44] No other modification in activity behaviors were reported,[44] and the lead scientist concluded: "Our study provides compelling evidence that the moon does not seem to influence people's behavior."[45] A study published in 2021 by researchers from the University of Washington, Yale University, and the National University of Quilmes showed a correlation between lunar cycles and sleep cycles. During the days preceding a full moon, people went to bed later and slept for shorter periods (in some cases with differences of up to 90 minutes), even in locations with full access to electric light.[46] Finally, a Swedish study including one-night at-home sleep recordings from 492 women and 360 men found that men whose sleep was recorded during nights in the waxing period of the lunar cycle exhibited lower sleep efficiency and increased time awake after sleep onset compared to men whose sleep was measured during nights in the waning period. In contrast, the sleep of women remained largely unaffected by the lunar cycle. These results were robust to adjustment for chronic sleep problems and obstructive sleep apnea severity.[47]
As for how the belief started in the first place, a 1999 study conjectures that the alleged connection of moon to lunacy might be a ‘cultural fossil’ from a time before the advent of outdoor lighting, when the bright light of the full moon might have induced sleep deprivation in people living outside, thereby triggering erratic behaviour in predisposed people with mental conditions such as bipolar disorder.[48]
In animals
Corals contain light-sensitive
Another marine animal, the bristle worm Platynereis dumerilii, also spawns a few days after a full moon. It is used as a model for studying cryptochromes and photoreduction in proteins. The L-Cry protein can distinguish between sunlight and moonlight through the differential activity of two protein strands that contain light-absorbing structures called flavins. Another molecule, called r-Opsin, may act as a moonrise sensor. Exactly how different biological signals are transmitted within the worm is not yet known.[6][7][8]
Correlation between hormonal changes in the
California grunion fish have an unusual mating and spawning ritual during the spring and summer months. The egg laying takes place on four consecutive nights, beginning on the nights of the full and new Moons, when tides are highest. This well understood reproductive strategy is related to tides, which are highest when the Sun, Earth, and Moon are aligned, i.e., at new Moon or full Moon.[53]
In insects, the lunar cycle may affect hormonal changes.
Evidence for lunar effect in reptiles, birds and mammals is scant,[52] but among reptiles marine iguanas (which live in the Galápagos Islands) time their trips to the sea in order to arrive at low tide.[55]
A relationship between the Moon and the birth rate of cows was reported in a 2016 study.[56]
In 2000, a retrospective study in the
In plants
Serious doubts have been raised[58] about the claim that a species of Ephedra synchronizes its pollination peak to the full moon in July.[59] Reviewers conclude that more research is needed to answer this question.[60]
See also
- List of topics characterized as pseudoscience
- Astrology
- Human menstrual cycle
- Menstrual synchrony
- Reproductive synchrony
- Solunar theory
- Tide
References
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- ^ Carroll, Robert Todd (12 August 2011). "Full Moon and Lunar Effects". The Skeptic's Dictionary. Retrieved 22 October 2011.
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- ^ Adams, Cecil (24 September 1999). "What's the link between the moon and menstruation?". The Straight Dope. Retrieved 14 December 2011.
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- ^ Attewill, Fred (5 June 2007). "Police link full moon to aggression". The Guardian. London. Retrieved 11 May 2010.
- ^ "Crackdown on lunar-fuelled crime". BBC News. 5 June 2007. Retrieved 26 July 2013.
- ^ "toledoblade.com – Analysis shines light on full Moon, crime". Archived from the original on 1 May 2020. Retrieved 27 July 2005.
- ^ Skeptic's Dictionary and Refuge: Mass Media Bunk
- ^ "Police busy for full moon". The Kentucky Post. E. W. Scripps Company. 29 January 2002. Archived from the original on 6 July 2007.
- ^ "Link between moon and crime supported – national". Stuff.co.nz. 7 February 2008. Archived from the original on 5 February 2009. Retrieved 11 July 2011.
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- ^ Riley, Alex (20 February 2016). "Playing Cupid to get reluctant corals in the mood for love". New Scientist.
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- ^ PMID 16407788. Archived from the originalon 26 June 2017. Retrieved 24 July 2015.
- ^ "What is a grunion?". Pepperdine University. Retrieved 17 September 2013.
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Bibliography
- Abell, George (1979). Review of the book The Alleged Lunar Effect by Arnold Lieber, ISBN 0-87975-314-5.
- Abell, George and Barry Singer (1981). Science and the Paranormal - probing the existence of the supernatural, ISBN 0-684-17820-6.
- Berman, Bob (2003). Fooled by the Full Moon - Scientists search for the sober truth behind some loony ideas, Discover, September 2003, page 30.
- Caton, Dan (2001). Natality and the Moon Revisited: Do Birth Rates Depend on the Phase of the Moon?, Bulletin of the American Astronomical Society, Vol 33, No. 4, 2001, p. 1371. A summary of the results of the paper.
- Diefendorf, David (2007), Amazing... But false! Hundreds of "facts" you thought were true, but aren't, ISBN 978-1-4027-3791-6
- Foster, Russell G.; Roenneberg, Till (2008). "Human Responses to the Geophysical Daily, Annual and Lunar Cycles". Current Biology. 18 (17): R784–R794. S2CID 15429616.
Lunar cycles had, and continue to have, an influence upon human culture, though despite a persistent belief that our mental health and other behaviours are modulated by the phase of the moon, there is no solid evidence that human biology is in any way regulated by the lunar cycle
- Packer, C.; Swanson, A.; Ikanda, D.; Kushnir, H. (2011). "Fear of Darkness, the Full Moon and the Nocturnal Ecology of African Lions". PLOS ONE. 6 (7): 22285. PMID 21799812.
- Palmer, JD; Udry, JR; Morris, NM (1982). "Diurnal and weekly, but no lunar rhythms in humans copulation". Human Biology; an International Record of Research. 54 (1): 111–21. PMID 7200945.
- Sanduleak, Nicholas (1985). The Moon is Acquitted of Murder in Cleveland, Skeptical Inquirer, Spring 1985, 236–42. Reprinted in Science Confronts the Paranormal, edited by ISBN 0-87975-314-5.
- Zimecki, Michał (2006). "The lunar cycle: effects on human and animal behavior and physiology". Postepy Higieny I Medycyny Doswiadczalnej. 60: 1–7. PMID 16407788. Archived from the originalon 26 June 2017. Retrieved 25 July 2015.
In fish the lunar clock influences reproduction and involves the hypothalamus-pituitary-gonadal axis. In birds, the daily variations in melatonin and corticosterone disappear during full-moon days. The lunar cycle also exerts effects on laboratory rats with regard to taste sensitivity and the ultrastructure of pineal gland cells. Cyclic variations related to the moon's phases in the magnitude of the humoral immune response of mice to polivinylpyrrolidone and sheep erythrocytes were also described. It is suggested that melatonin and endogenous steroids may mediate the described cyclic alterations of physiological processes. The release of neurohormones may be triggered by the electromagnetic radiation and/or the gravitational pull of the moon
External links
- The Skeptic's Dictionary on the lunar effect
- McGowan, Iain; Owens, Mark (2006). "Madness & The Moon: The Lunar Cycle & Psychopathology". German Journal of Psychiatry. 9 (1): 123–127. CiteSeerX 10.1.1.511.5967.
- McDowall, R. M. (December 1969). "Lunar Rhythms in Aquatic Animals: A General Review". Tuatara. 17 (3): 133–143.
- Linley, G. D.; Pauligk, Y.; Marneweck, C.; Ritchie, E. G. (2021). "Moon phase and nocturnal activity of native Australian mammals". Australian Mammalogy. 43 (2): 190. S2CID 219918342.