Is There Really Odd Behavior When the Moon Is Full?

When things seem off, chaotic, or just plain strange, we’re quick to ask this: “Is there a full moon tonight?” For centuries, people have believed that the full moon brings out unusual behavior in humans. From emergency room surges to bizarre public incidents, stories about the “lunar effect” are widespread in both folklore and modern culture. But is there any truth to these claims?

The History of Full Moon Lore

Beliefs about the full moon’s power date back to ancient civilizations. The word lunatic comes from luna, the Latin word for moon, reflecting the long-standing belief that lunar cycles influence mental health and behavior. Ancient Greeks and Romans thought the full moon could incite madness, while in medieval Europe, it was linked to werewolves, witches, and sorcery.

In modern times, emergency service workers, police officers, and hospital staff often share anecdotal evidence of heightened activity during full moons. Sergeant Al Shaffer, with the Newark Police Department, tells us this: “As a 29-year veteran of the Newark Police Department, I’ve seen my share of wild nights. More times than I can count, I’ve heard officers say, ‘It must be a full moon.’ And, truth be told, sometimes it actually was.”

The Moon’s Gravitational Pull: More Than Just Tides?

It’s a scientific fact that the moon’s gravitational pull affects Earth’s tides. But it does more than raise and lower ocean levels. In fact, the moon actually tugs on the Earth itself — ever so slightly stretching the planet into an oval shape, especially near the equator. Scientists call this “Earth tide” and though the shift is tiny — measured in centimeters — it’s a real and measurable deformation of the planet’s surface.

Now consider this: if the moon can pull at the Earth’s crust and move entire oceans, could it also affect our bodies, which are composed mostly of water? Some researchers and spiritual thinkers speculate that even if the effects are too subtle to measure directly, they may influence us subconsciously. Our circadian rhythms, hormonal cycles, and even mood might be nudged ever so slightly by the moon’s phases. While science hasn’t conclusively proven this, it remains a compelling line of thought that fuels continued research and curiosity.

This can be compared to women’s menstrual cycles. Men, take note — many don’t even realize what’s happening during a period. The body is shedding an unfertilized egg, contracting and flushing out material that’s no longer needed. It’s a natural force, just like the pull of a full moon. And while women often get dismissed as “cranky” or “PMS-ing,” it’s undeniable that these forces, though unconscious, have real impact on mood.

The Power of Expectation and Perception

One major factor contributing to the belief in full moon effects is confirmation bias. If someone expects strange things to happen during a full moon, they are more likely to notice and remember odd incidents — and less likely to recall similar events on other nights. This phenomenon plays a powerful role in shaping our perceptions and reinforcing superstitions.

Sgt. Shaffer explained it this way: “When I step back and look at it more carefully, the evidence just isn’t there. Studies show very little proof that full moons cause more crimes or 911 calls. What really seems to happen is something called confirmation bias. Here’s how it works: if I have a very busy night on patrol, then look up and see the full moon, I connect the two. That ‘confirms’ the old belief, even if the moon had nothing to do with it.”

Additionally, the media often highlights bizarre stories that coincide with the full moon, further embedding the idea that the moon influences behavior.

So, Does the Full Moon Really Change Us?

It doesn’t seem so. “The truth is, there’s no strong statistical link between moon cycles and crime. The real reasons for busy nights are things like alcohol, large crowds, holidays, or big events in the city,” Sgt. Shaffer said.

“Still, the folklore around the full moon isn’t going away. People like to find meaning in what they see, and a glowing full moon is a powerful symbol. Even today, after a hectic shift, you might still hear officers say, ‘It must be a full moon.’ Sometimes it is — and sometimes it’s not,” he said.

The moon has pulled at the Earth since time began. Maybe it’s not so far-fetched to think it tugs at us, too.