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It seems like an accepted fact that a full moon makes kids “hyper” or people behave in a crazy way. Is there any truth to this, or is it just an old wives tale? – BH, Watertown, ME

Thanks for the question, BH! This is one of those “common knowledge” beliefs that seems to be everywhere. About 45% of people actually think this is true, which is in line with about 50% of Americans that think astrology is a science. This should make us all sad, because astrology is not a science and more people believe in astrology today than in 2004.

As for the full moon and behavior, this was a big enough question on peoples mind that several groups of scientists actually ran studies to see if there really was an effect on behavior. Universally, they found that there is none, though there was a very small decrease in the amount of sleep that children got during a full moon, which may be related to all that moonlight coming into their window, or to their parents repeatedly telling them that they were “hyper” because of the moon.

Exactly why people believe this is a bit of a mystery. Certainly, it has been around for a long time – this is where the words “lunacy” and “lunatic” comes from – from the Latin lunaticus, which referred to madness or epilepsy because people thought the moon caused these effects. It could be that this is just a relic of the past before electricity when nights with a bright moon in the sky would have allowed for much more activity than dark moonless nights, or maybe just kept people from getting a good night’s sleep.

Many people have anecdotally suggested that the full moon increases the rates of crimes, accidents, suicides, or trips to the emergency rooms. Scientists have studied these links as well, and there is no consistent effect of the phase of the moon on any of them. The same is true for animal behavior.

Others think that the behavioral effects might be related to the gravitational effect that causes tides, but this is not how tides work – they are driven not just by the gravitational pull of the moon, but also the large distances between different regions of the ocean. This is why the pond behind your house doesn’t have tides. The local gravity that a person experiences is influenced more by their distance from the center of the Earth and other large objects around them than the moon.

The bottom line is that the moon doesn’t effect behavior in any consistent way. If your kids are “hyper”, it’s not the moon, and it’s not sugar – maybe they are just kids having a good time?