# Does the Full Moon affect human behavior? **URL:** \ **Category:** Factual Questions\ **Created:** [March 23, 2004, 12:10pm UTC](https://boards.straightdope.com/t/does-the-full-moon-affect-human-behavior/235885 "2004-03-23T12:10:25Z")\ **Posts on this page:** 19\ **Page:** 1
**Author:** ![Starguard](https://avatars.discourse-cdn.com/v4/letter/s/8dc957/32.png) [@Starguard](https://boards.straightdope.com/u/Starguard)\ **Post date:** [March 23, 2004, 12:10pm UTC](https://boards.straightdope.com/t/does-the-full-moon-affect-human-behavior/235885/1 "2004-03-23T12:10:25Z")
I’m not talking about people changing into Werewolves or anything crazy like that. I mean the full moon affecting our behavior in a _moderate_ way. I’ve read scientific reports before stating that since most people believe that the human body is supposedly made up of over 70% water ( give or take a few percentages ), the gravitational pull of the moon would effect the water in our bodies the same way it effects the tide in the oceans, thus making us more physically active. But scientific studies have firmly proven this to be false. (Something to do with the mass of our bodies or something like that). Regardless of this “fact”, the full moon still has been associated with several other behavioral patterns that have yet to be explained “_at least to me anyway_”. Some examples are: It is believed by many that People tend to become more “Romanticized” or “Sexually Enchanted” during full moons…(especially writers of several romance novels) Police reports in some urban areas have shown a slight rise in violent crimes and domestic issues during periods of the full moon…( **note** : these reports also state that these rises are not constistant from month to month, but are more often than not) In a few mental institutions ( not all ), several doctors and nurses have reported seeing a slight rise in the overall level of restlessness in most of their patients during periods of the full moon. (\*\* Note:\*\* These reports also state these incidents are not consistant from month to month, but are more often than not) There are several others that escape my mind at the moment, but I will post them later as they all come to mind… _even the origin of the fictional stories about Werewolves themselves supposedly origionated from this belief_ So far, no one that I have heard of has provided any solid proof or eveidence that the gravitational forces of the full moon is directly responsible for any of these events. But it is still believed my many that they are. What I would like to know is, Do \*\* you \*\* think it is? If so…why? ---
**Author:** ![tomndebb](https://avatars.discourse-cdn.com/v4/letter/t/b9e5f3/32.png) [@tomndebb](https://boards.straightdope.com/u/tomndebb)\ **Post date:** [March 23, 2004, 12:20pm UTC](https://boards.straightdope.com/t/does-the-full-moon-affect-human-behavior/235885/2 "2004-03-23T12:20:42Z")
As far as I am aware, every study using incident reports or police blotters has been shown to have been cherry-picked from larger sources that do not support the conclusions. I would think that there is a remote chance that some people, hearing that they are “supposed” to be more wild during a full moon, might experience a slight suppression of their inhibitions, but I have also noticed that such people do not even pay attention to the exact day of the full moon, often picking any day within two days before or after the full moon to “excuse” their behavior because it “looks” full. ---
**Author:** ![Kinthalis](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/kinthalis/32/16084_2.png) [@Kinthalis](https://boards.straightdope.com/u/Kinthalis)\ **Post date:** [March 23, 2004, 12:23pm UTC](https://boards.straightdope.com/t/does-the-full-moon-affect-human-behavior/235885/3 "2004-03-23T12:23:05Z")
> [@Starguard](#): > > But scientific studies have firmly proven this to be false. Yep, a lot of bunk. The earth (I might be wrong, but I think even the sun) would have a much higher effect on us. > [@](#): > > Regardless of this “fact”, the full moon still has been associated with several other behavioral patterns that have yet to be explained “_at least to me anyway_”. Some examples are: I don’t really need to even hear the examples (although I did read them). They are very subjective and almost ALWAYS can be explained with a very simple human quality: Selective memory. I’ll give you an example: When my father died, me and my family were discussing many weird things death makes you think about. Some of my family members recalled how, near their home there were a lot of crows. And how it was said that everytime a crow sat on the window sill of a house someone from that family just died or was about to die. They swore up and down that this was true, because everytime there was a death in their family or a friend’s family a crow would stop to relax by a window sill. But the real truth is that crows sat on window sills all the time, it was a common occurance, however, they only remebered the times there was a crow on the window sill AND someone died. Same thing happens in hospitals. If you were to take a look at admittance charts you’d see that there is no significant elevation in the number of patients during a full moon, but doctors and nurses will remeber that one or two days that it was a little hectic in the OR AND it was a full moon, but not the thursday, last week, when it was even more hectic, and there wasn’t a full moon. It’s all selective memory. BTW, the police reports have also been debunked, unless you have a cite proving that criminal activity rises on the full moon? ---
**Author:** ![scr4](https://avatars.discourse-cdn.com/v4/letter/s/59ef9b/32.png) [@scr4](https://boards.straightdope.com/u/scr4)\ **Post date:** [March 23, 2004, 12:23pm UTC](https://boards.straightdope.com/t/does-the-full-moon-affect-human-behavior/235885/4 "2004-03-23T12:23:44Z")
I’m sure the presence of a bright light source in the night sky affects human behavior. Amateur astronomers become less active, for example. 🙂 If you’re strictly talking about the moon’s gravity (or tidal force) affecting human psychology, forget it. There’s no theory predicting that there should be a measurable effect, and there is no evidence for such an effect. ---
**Author:** ![Starguard](https://avatars.discourse-cdn.com/v4/letter/s/8dc957/32.png) [@Starguard](https://boards.straightdope.com/u/Starguard)\ **Post date:** [March 23, 2004, 12:28pm UTC](https://boards.straightdope.com/t/does-the-full-moon-affect-human-behavior/235885/5 "2004-03-23T12:28:48Z")
> [@Kinthalis](#): > > I don’t really need to even hear the examples (although I did read them). They are very subjective and almost ALWAYS can be explained with a very simple human quality: Selective memory. That is something I can easily believe ---
**Author:** ![Bromley](https://avatars.discourse-cdn.com/v4/letter/b/4da419/32.png) [@Bromley](https://boards.straightdope.com/u/Bromley)\ **Post date:** [March 23, 2004, 12:38pm UTC](https://boards.straightdope.com/t/does-the-full-moon-affect-human-behavior/235885/6 "2004-03-23T12:38:10Z")
[Cecil](http://www.straightdope.com/classics/a2_337.html) on full moon fever. On a related note, [Cecil](http://www.straightdope.com/classics/a990924.html) on menstruation & the moon. ---
**Author:** ![Philster](https://avatars.discourse-cdn.com/v4/letter/p/13edae/32.png) [@Philster](https://boards.straightdope.com/u/Philster)\ **Post date:** [March 23, 2004, 1:08pm UTC](https://boards.straightdope.com/t/does-the-full-moon-affect-human-behavior/235885/7 "2004-03-23T13:08:58Z")
visit [www.skepdic.com](http://www.skepdic.com) (the skeptics dictionary), which has an excellent review of the issue. It’s alphabetical, so you’ll find it under moon, or full moon. It’s also a great resource for a number of topics, with tons of links to factual findings, double blind studies and such. Generally, there is no correllation. Also, you’ll find it interesting in surfing around that there is no connection between the Superbowl and domestic violence, prize fights and violent crime…etc… ---
**Author:** ![Dog80](https://avatars.discourse-cdn.com/v4/letter/d/6bbea6/32.png) [@Dog80](https://boards.straightdope.com/u/Dog80)\ **Post date:** [March 23, 2004, 3:08pm UTC](https://boards.straightdope.com/t/does-the-full-moon-affect-human-behavior/235885/8 "2004-03-23T15:08:43Z")
> [@Starguard](#): > > I’m not talking about people changing into Werewolves or anything crazy like that. I mean the full moon affecting our behavior in a _moderate_ way. I’ve read scientific reports before stating that since most people believe that the human body is supposedly made up of over 70% water ( give or take a few percentages ), the gravitational pull of the moon would effect the water in our bodies the same way it effects the tide in the oceans, thus making us more physically active. The moon’s gravitational pull has the same effect in the whole body, not just our water molecules. It’s also a misconception that only water bodies are lifted during tidal waves. Land rises too! ---
**Author:** ![Annie-Xmas](https://avatars.discourse-cdn.com/v4/letter/a/ecc23a/32.png) [@Annie-Xmas](https://boards.straightdope.com/u/Annie-Xmas)\ **Post date:** [March 23, 2004, 3:24pm UTC](https://boards.straightdope.com/t/does-the-full-moon-affect-human-behavior/235885/9 "2004-03-23T15:24:02Z")
Under “Bridey Murphy,” [www.skepdic.com](http://www.skepdic.com) refers to the column by Cecil 😃 ! ---
**Author:** ![beajerry](https://avatars.discourse-cdn.com/v4/letter/b/7bcc69/32.png) [@beajerry](https://boards.straightdope.com/u/beajerry)\ **Post date:** [March 23, 2004, 4:17pm UTC](https://boards.straightdope.com/t/does-the-full-moon-affect-human-behavior/235885/10 "2004-03-23T16:17:52Z")
Working in a hospital on the night shift, you invariably get people who swear that there is more ER action on full moon nights (especially saturday full moon nights). So, I’m constantly pointing out the other **non-full moon** nights when the ‘action’ was the same or even greater. It doesn’t help sway this tired persistent belief. ---
**Author:** ![Ring](https://avatars.discourse-cdn.com/v4/letter/r/6a8cbe/32.png) [@Ring](https://boards.straightdope.com/u/Ring)\ **Post date:** [March 23, 2004, 4:17pm UTC](https://boards.straightdope.com/t/does-the-full-moon-affect-human-behavior/235885/11 "2004-03-23T16:17:56Z")
I know very little about astronomy but why would the amount of light reflected by the moon affect its gravitational field? Is it closer to the earth at this time of the month or something? ---
**Author:** ![detop](https://avatars.discourse-cdn.com/v4/letter/d/bcef8e/32.png) [@detop](https://boards.straightdope.com/u/detop)\ **Post date:** [March 23, 2004, 4:26pm UTC](https://boards.straightdope.com/t/does-the-full-moon-affect-human-behavior/235885/12 "2004-03-23T16:26:17Z")
> [@Starguard](#): > > There are several others that escape my mind at the moment, but I will post them later as they all come to mind… _even the origin of the fictional stories about Werewolves themselves supposedly origionated from this belief_ Actually, this is a Hollywood invention (as well as the silver bullet). In traditional folklore (at least Western European folklore), a person became a werewolf after either making a pact with the Devil or undertaking rituals to become one (usually involving the wearing of a wolf skin). ---
**Author:** ![Cervaise](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cervaise/32/16693_2.png) [@Cervaise](https://boards.straightdope.com/u/Cervaise)\ **Post date:** [March 23, 2004, 6:35pm UTC](https://boards.straightdope.com/t/does-the-full-moon-affect-human-behavior/235885/13 "2004-03-23T18:35:03Z")
> [@Ring](#): > > I know very little about astronomy but why would the amount of light reflected by the moon affect its gravitational field? Is it closer to the earth at this time of the month or something? No, it’s not related to the mass of the moon. You’re right, more light != more gravity. It has to do with the position of the moon _and the sun_ relative to the earth. Try to visualize: The light from the moon is reflected from the sun. When we have a half moon, that means the sun is oriented off to the left or right relative to where we’re standing and looking. And when we have a full moon, that means the sun is more or less behind us, illuminating the whole visible face of the moon. (If it were _directly_ behind us, we’d have a lunar eclipse.) So on nights where there’s a full moon, the earth is approximately on a line between the sun and the moon, obviously much closer to the moon. Now: Tides rise not just on the side of the earth facing the gravitational body, but on the opposite side as well. This is kind of complicated, so in my mind I simplify the model so the tides on the near side are being pulled by the body while the tides on the far side are being flung outward due to angular momentum. (Same thing that keeps the water in the bottom of a bucket being whirled around on a rope.) That’s not a strictly accurate model, but it’s simple enough for our purposes. The rise and fall of tides reflects a complex gravitational attraction of not just the moon but also the sun. When the effect of the sun and the moon “lines up,” so to speak, you get higher tides. And we can tell when we’re lined up because the moon will be full, completely lit by the sun behind us. Make sense? ---
**Author:** ![RogueRacer](https://avatars.discourse-cdn.com/v4/letter/r/7ab992/32.png) [@RogueRacer](https://boards.straightdope.com/u/RogueRacer)\ **Post date:** [March 23, 2004, 7:20pm UTC](https://boards.straightdope.com/t/does-the-full-moon-affect-human-behavior/235885/14 "2004-03-23T19:20:27Z")
I do some local stock car racing during the summer. There are definitely people who believe that nights with a lot of crashes are linked to the moon being full. There are many times when after a nasty wreck I have heard comments like, “I had to check to see if there was a full moon.” I have watched this myself just to see if there was a connection with aggressive driving on the track. For the most part, my conclusion is the same as mentioned in other posts. People remember when there are a lot of wrecks and a full moon, but ignore the clean nights with a full moon or the wreck filled nights with other moon phases. I do think that there is a little bit of a self-fulfilling prophecy going on too. There are times that it seems like some drivers use the full moon as an excuse to drive like an idiot. ---
**Author:** ![Philster](https://avatars.discourse-cdn.com/v4/letter/p/13edae/32.png) [@Philster](https://boards.straightdope.com/u/Philster)\ **Post date:** [March 23, 2004, 7:47pm UTC](https://boards.straightdope.com/t/does-the-full-moon-affect-human-behavior/235885/15 "2004-03-23T19:47:12Z")
As pointed out in [Skepdic.com](http://Skepdic.com), anything close to a full moon is declared a full moon. This is called shoe horning - making things fit when they really don’t. ---
**Author:** ![El\_Zagna](https://avatars.discourse-cdn.com/v4/letter/e/d2c977/32.png) [@El\_Zagna](https://boards.straightdope.com/u/El_Zagna)\ **Post date:** [March 23, 2004, 7:49pm UTC](https://boards.straightdope.com/t/does-the-full-moon-affect-human-behavior/235885/16 "2004-03-23T19:49:39Z")
> [@Cervaise](#): > > The rise and fall of tides reflects a complex gravitational attraction of not just the moon but also the sun. When the effect of the sun and the moon “lines up,” so to speak, you get higher tides. And we can tell when we’re lined up because the moon will be full, completely lit by the sun behind us. The same thing also happens during a new moon when the bodies are lined up earth–\>moon–\>sun as opposed to a full moon: moon–\>earth–\>sun. I’ve always assumed that new moon tides would be greater than full moon tides since you have both objects pulling in one direction. (I’m sure this is stated on the Web somewhere, I just couldn’t find it.) If my assumption is correct, and if the presumed difference in human behavior is based on gravitational (tidal) pulls, then you should expect even greater numbers of crimes, injuries, car accidents, etc. during new moons than during full moons. ---
**Author:** ![Ring](https://avatars.discourse-cdn.com/v4/letter/r/6a8cbe/32.png) [@Ring](https://boards.straightdope.com/u/Ring)\ **Post date:** [March 23, 2004, 8:02pm UTC](https://boards.straightdope.com/t/does-the-full-moon-affect-human-behavior/235885/17 "2004-03-23T20:02:28Z")
> [@Cervaise](#): > > Make sense? Sort of. There’s no doubt that when the sun and moon are approximately opposite each other that the horizontal differential tidal forces are greatest. But it would seem that their actual gravitational attraction on us would tend to cancel. On the other hand when there’s a quarter moon it would seem the forces would tend to reinforce. I guess we could look at it from the other direction and consider the Earth’s gravity to be stronger at spring tide and weaker at neap tide. Man that pop up screen for guest posting is aggravating. ---
**Author:** ![Ring](https://avatars.discourse-cdn.com/v4/letter/r/6a8cbe/32.png) [@Ring](https://boards.straightdope.com/u/Ring)\ **Post date:** [March 23, 2004, 8:48pm UTC](https://boards.straightdope.com/t/does-the-full-moon-affect-human-behavior/235885/18 "2004-03-23T20:48:51Z")
> [@bnorton](#): > > I’ve always assumed that new moon tides would be greater than full moon tides since you have both objects pulling in one direction. (I’m sure this is stated on the Web somewhere, I just couldn’t find it.) I don’t think that’s true **bnorton.**. I’m not sure but I don’t think the force vertical to Earth’s surface plays much of a part in producing tides. I think it’s pretty much the tangential component pulling the oceans along the surface towards the axis connecting the center of the Earth and the common center of mass. ---
**Author:** ![El\_Zagna](https://avatars.discourse-cdn.com/v4/letter/e/d2c977/32.png) [@El\_Zagna](https://boards.straightdope.com/u/El_Zagna)\ **Post date:** [March 23, 2004, 9:43pm UTC](https://boards.straightdope.com/t/does-the-full-moon-affect-human-behavior/235885/19 "2004-03-23T21:43:44Z")
See Figure 8r-2 [this](http://www.physicalgeography.net/fundamentals/8r.html) to see what I’m talking about. Even if there is no appreciable difference between the full-moon and new-moon tides, you still have _spring_ tides (the strongest tides) during each of those two periods. Ah-ha! I did find [this](http://www.enchantedlearning.com/subjects/astronomy/moon/Tides.shtml): > [@](#): > > The Proxigean Spring Tide is a rare, unusually high tide. This very high tide occurs when the moon is both unusually close to the Earth (at its closest perigee, called the proxigee) **and in the New Moon phase** (when the Moon is between the Sun and the Earth). The proxigean spring tide occurs at most once every 1.5 years.