The Lunar Effect


The “Lunar Effect”, sometimes called the “Transylvania Effect” is the notion that the phases of the moon have a note-worthy effect on human behaviour and mental health (Neil, Colledge 2000). More specifically, the idea that when there is a full moon people are more likely to act out, commit crimes, become injured and the like. This theory also posits that the gravitational effect of the moon effects things such as how the body behaves during surgery and with fertility.

The following video from Two Minute Universe briefly explains the Lunar Effect:

While that video may be a little bit comical, especially toward the end, it should serve to elucidate what exactly the Lunar Effect is and why it is a thing worth discussing. During the discussion of the Lunar Effect throughout this article I will try to present as strong a case for the Lunar Effect as possible before showing why it is still a pseudoscience.

Lunar Effect Explained


The idea of a “lunar effect” seems to be a rather commonplace belief among people in general. It is often heard of, for example, a teacher at an elementary school saying that as the children are acting up it must be a full moon. In comic books, films, and fiction the notion of a werewolf that transforms at the full moon is also frequently used. That being said there is a very real history to this idea. While it has been linked to the Babylonians among others I think the linguistic tie between the moon and insanity are very interesting. For example the linguistic tie between insanity and the moon can be traced back to at least the 13th century with the word “lunatic”. This word is derived from the Latin phrase “lunaticus” which means “to be moon-struck”(Etymology Online). Although this may not be the first case of the moon being used to describe or explain insanity, its is worth noting that it is still used presently.

To be sure there must be many other examples of a connection between moon and people in ancient pagan religions, but it is much easier to find well documented connections such as those found in linguistics. The point that is important is that the notion of the moon influencing our behaviour is not a recent development and is so thoroughly entrenched in our collective consciousness that it is even pervasive in our language.

While there seem to be very few clear examples of historical references to the moon influencing our behaviour, it seems as though it's something that is always, at least in part, taken for granted. It seems to be relatively pervasive throughout our society that there is at least a minimal connection between us and the moon. This perceived connection has manifested in many ways, and is one that people seem hard-pressed to let go of.


As previously mentioned, the moon as a trigger for insanity in people is very common in fiction, especially in relation to werewolves. The connection in these seems to reflect the notion of “lunacy”, the idea that as soon as there is a full moon not only does the mind change to a sort of insanity but the body as well. An interesting, and not entirely unrelated, observation is that wolves seem to howl at the moon as well. While this may not be crucial to the theory, it is another coincidence around the idea of the moon influencing nature that is worth noting. More importantly than that, however, it seems that people do actually hold the belief that the moon influences our actual behaviour, not just in fairy tales. While it may not be uncommon to hear someone say something dismissive, along the lines of “well the children are acting up, it must be a full moon”, sometimes that train of thought is taken very seriously by people in positions of authority.
A good example of people of authority taking this seriously is that in 2007 the police in Brighton, England decided that there was a link between full moons and aggressive behaviour in citizens. They decided that the appropriate way to respond to this information was by deploying more police officers accordingly (Attwil, 2007). Likewise in 2008, the Justice Minister of New Zealand, Annette King, commented that the moon cycle could be to blame for a surge in violence. It is worth noting,h owever, that oether people in New Zealand dismissed this comment as a joke, this is illustrated by an MP, Dr Wayne Mapp, “I think the minister needs to get a grip on reality” (Fairfax News 2008).
Another correlation that is often noted is that the lunar cycle comparable to the average menstrual cycle of women. This seems to suggest that there might be a connection between fertility and the moon, or at least according to people who believe in the Lunar Effect. While some people believe this, it does not seem to be a very widely held belief, though definitely a note worthy one. This is a topic that is addressed bellow in the brief discussion by Neil Degrass Tyson on the topic of the lunar effect.
Yet Another example of people taking the full-moon notion seriously is the idea that the moon has an effect on surgery, specifically in relation to blood clotting. A prominent politician in the UK, David Tedennick, for example, says “In 2001 I raised in the House the influence of the moon, on the basis of the evidence then that at certain phases of the moon there are more accidents. Surgeons will not operate because blood clotting is not effective and the police have to put more people on the street.”(Tedennick, 2009) I think what is most shocking about this quotation is the fact that there is a person in office who actually believes that surgeons all just collectively take a day off whenever there's a full moon. That aside, I believe a very acute response to this is best demonstrated by Neil Degrass Tyson in the following video when he discusses the effect of gravity of the moon on people, and on the lunar cycle in relation to fertility:

But Is The Lunar Effect A Science?

The Lunar Effect is, if assumed to be actually scientific and not a pseudo-science, essentially a social science. I say this as social sciences deal more with behaviour of people and more abstract ideas. As the lunar effect is a theory which states that when there is a full moon people at large will act differently, I believe it fits under this category. As this would be a social science theory it seems as though it would have to follow a different set of a criteria that would prove it to be either a pseudo-science or not. For this case I believe that proof for this theory would have to consist of a noteworthy statistical difference in behaviour on days when there is a full moon. If it were found that there were no noticeable difference for those days, we could say that this theory is decidedly false.

To give an example of a sort of proof of this theory, there have been claims that the crime rates are higher on nights with a full moon. In 1978 a study was released which showed that there were more cases of assault that happened on a full moon than any other day of the month (Lieber, 1978). Furthermore in 2009 a thirty six year study was concluded which showed that there were fewer people treated for trauma when there was a full moon, although there was only a small decrease (Surq, 2004). One more example is taken from Neuroscience For Kids, they describe a study which found that of “130 patients who suffered a rupture of an abdominal aortic aneurysm: significantly more ruptures during the waxing moon period.” (Neuroscience for Kids).
If it were found that there are far more studies that show this outcome than ones that show that there is no noticeable increase/decrease on the full moon, it would seem as though this theory is more likely to be true. That would make this theory seem more likely to considered to have scientific validity. Likewise this theory would be falsified if contrary to that the studies showed that there was no correlation between full moons and the previously discussed events.
That being said the studies have in reality overwhelmingly shown that there is no constant correlation between full moons and these sorts of events and states of affairs. It seems as those these two studies were anomalies as in an article by the Skeptic's Dictionary, the author says 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 [a list of things generally associated with 'lunar theory']”. (Skeptic's Dictionary, 2011) It seems as though any correlation that has been shown, has been very rare and so is associated with chance.

Why The Lunar Effect Is A Pseudoscience

The difference between Pseudoscience and Science

The Stanford Philosophy Dictionary explains that the goal of both science and pseudo-science is, very broadly, the endeavour of “systematic and critical investigations aimed at acquiring the best possible understanding of the workings of nature, man, and human society.” (SPU). The noteable difference however is that the community associated with the pseudo-sciences are very much in conflict with the methods and conclusions of the scientific community.
There are many ways to differentiate between science and pseudo-science. Among which include whether the researchers are accredited, how the theory responds to new information, whether it makes risky predictions and so on. Karl Popper, for example, said that in order for something to be a science it must be falsifiable. In his essay Popper says first that “the criterion of the scientific status of a theory is its falsifiability, or refutability, or testability.”(Popper, 1963) He also says that a sign of a theory that is not genuinely scientific, is one which in spite of being found false, people still find reason to believe in it. He says:
Some genuinely testable theories, when found to be false, are still upheld by their admirers — for example by introducing ad hoc some auxiliary assumption, or by reinterpreting the theory ad hoc in such a way that it escapes refutation. Such a procedure is always possible, but it rescues the theory from refutation only at the price of destroying, or at least lowering, its scientific status. (Popper, 1963)

At this point it is worth briefly discussion the notion of causation and correlation. Causation is the notion that event A causes event/state of affairs B. Correlation is used to explain the notion that whenever there is an event A, there is also event/state of affairs B. Correlation can be caused by coincidence or complete chance. An example to help elucidate this is found on the website Neuroscience For Kids when the author suggests a hypothetical situation in which it seems as though whenever there is a high basketball score more books are checked out of the library. The author suggests that the high basketball score does not cause more books to be checked out of the library but that both of those events just happen at the same time. A possible explanation might be that it's raining outside which causes the basketball teams to practice more and cause more people to go to the library. The point being that not every noteworthy correlation is the result of a causal relation.

Applied to Lunar Effect

When we take this and apply it to the “lunar effect theory” we note that it does in fact make a large prediction- that people will act noticeably different during full moons, or that blood will not clot as well during full moons. However there has been shown countless times over that there is no meaningful correlation whatsoever, and yet people still cling to this theory. For example, in an article by the Skeptic's Dictionary, the author says 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 [a list of things generally associated with 'lunar theory']” (the list mentioned in the quotation is rather comprehensive but includes things such as violent crimes, pregnancies, suicides and car accidents among other things). (Skeptic's Dictionary, 2011)
Consequently, we can conclude from the fact that this theory is still used to describe phenomena, even when found to be overwhelmingly wrong in the face of a large base of evidence, that this theory is not scientific. It is a pseudoscience in that it does not adequately explain anything and is still held to be true contrary to a lot of evidence. While it may have risky predictions, the fact that a failure for those predictions to be met is usually answered with various explanations suggests that this theory is not scientific after all.
So if the theory fails so often, why do people still consider it to be true? The people mentioned in the Skeptic's Dictionary suggest that it may be due to the simple fact that it is prevalent in our society, that the media reinforces the idea and that our language does as well. Furthermore the fact that the news seems to reinforce this idea relatively frequently, even if only with flippant remarks about people acting out as it's a full moon, likely contributes to the notion that the moon actually does play a role in our behaviour. Essentially the fact that it socially engrained in us to feel as though it effects us will cause us to think that it effects us, and will cause us to repeat that it effects us. Regardless, the point remains that if it is a falsifiable theory that has been proven false, and if people still consider it to be true, it most certainly is not science.

Why Lunar Effect as a Theory is Bad For People in General

While it seems as though this theory is marginally harmless, as it seems to just hypothesize that people are more likely to commit crimes and the line on a certain day of the month, I believe it is still at least a bit harmful. The sort of harm that can come from this could be divided into two categories, I believe. The first being more plausible, the cost to people in general. The second would be a sort of butterfly effect if this theory were spread and everyone were to adopt it.
As mentioned the first of the possible harms was the cost to people in general. Let us return to the example of the police officers who suggested that they would increase police presence during a full moon. What would most likely be the case in this scenario is that the increase in police presence would cost tax payers slightly more in increased spending on police expenditures. This would likely not be a huge harm to the people in general, but still an unnecessary one.
What could be the larger harm, although seems much more unlikely, falls under the second category I gave, which is the one stemming from a sort of butterfly effect, as it were. Taking the example of hospitals and surgery to an extreme, imagine a person who has requires a surgery to be done which would save their life but they refuse to get it done because the moon is full and they refuse to have surgery done during a full moon. They would be more likely to pass away. Moreover imagine a world such that the surgeons refuse to perform surgery on a full moon because there is a lower survival rate, or at least they think there is. People who need treatment would have to wait an extra day which could be very harmful. Of course these are rather extravagant hypothetical situations.
More reasonably than either of those categories, one of the main reasons this theory might be harmful to hold is that it alleviates responsibility from people. One can simply explain away behaviour by blaming it on the moon. If this is taken seriously we could conceive of people being let off from criminal charges with the excuse of having done whatever the crime is on a full moon among other things.
Essentially all of these examples were rather fantastic hypothetical scenarios and none of them are too terribly convincing. I do not believe that this is a particularly dangerous theory to hold to be true consequently. The largest problem is that it seems to impede on a better understanding of people by accounting for certain observations and dismissing them with the idea that the moon was to blame.


Lunar Effect is a theory which has no ration ground for continued belief. It is very much a pseudoscience and has been proven to be false countless times.


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