Unraveling the Full Moon Myth: The Science Behind Lunar Lunacy and Illusory Correlations

Have you ever noticed odd occurrences and thought, “There must be a full moon out there”? You're not alone. Many believe the full moon influences human behaviour, attributing strange events to this celestial phenomenon. This belief isn't new; it stretches back to ancient times when the Roman goddess of the moon, Luna, whose name is the root of the word “lunatic,” was thought to wield immense influence over our lives. The Greek philosopher Aristotle and Roman historian Pliny the Elder proposed that the brain, the “moistest” organ, was highly responsive to the moon's influence, much like the tides it controls. 


Luna, the Roman goddess of the moon, is the root of the word “lunatic,” highlighting the long-standing connection between the moon and perceived erratic behaviour.

Despite these long-held beliefs, modern science has a different perspective. According to Scientific American, phenomena like the “lunar lunacy effect” or “Transylvania effect” are classic examples of an illusory correlation. This is where we perceive a relationship between two variables that don’t exist. For instance, think about how some people claim their joint pain worsens with wet, rainy weather. Research doesn’t support this connection either, yet the belief persists. So, is the full moon truly a harbinger of chaos or simply a case of mistaken correlation?

solar eclipse

The Moist Brain Theory: Aristotle’s Influence on Moon Myths

Aristotle’s notion that the brain, being the moistest organ, was particularly vulnerable to the moon’s influence is a compelling example of early scientific theory blending with myth. Pliny the Elder further bolstered this idea, proposing that the same forces affecting the tides could impact the human psyche equally. Such theories were widely accepted during their time, forming a foundation for later misconceptions linking lunar cycles with human behaviour. 

Interestingly, these beliefs likely offered a form of psychological comfort. People felt they had control over unpredictability by attributing unexplainable behaviours to the full moon. This ancient form of reassurance helped cement the moon’s influence in popular notions about human behaviour, even as modern science challenged and debunked these ideas. 

Today, we understand the moon’s primary effects relate to tides and do not extend to altering human biology in the dramatic ways suggested by historical figures. Nonetheless, Aristotle’s and Pliny’s ideas remain fascinating, illustrating how early thinkers combined observation with imaginative explanations to understand the world around them. Their theories, though incorrect, illuminate the evolving relationship between human culture and scientific inquiry.

Transylvania Effect: Werewolves, Vampires, and Full Moon Myths

Even in modern times, the Transylvania Effect holds a fascinating sway over our imaginations. Films, books, and TV shows brim with tales of lycanthropy and bloodsuckers, capturing our fascination with the supernatural. The archetypal image of the werewolf transforming under the silvery glow of a full moon continues to resonate deeply within popular culture. 

This connection isn’t just the stuff of folklore. Some historical theories suggest that living conditions, particularly before the advent of modern indoor lighting, may have amplified behaviours we now associate with lunar phases. For instance, the bright illumination of a full moon might have disrupted sleep patterns, potentially exacerbating mental health issues and fuelling tales of night-time transformations. 

The term “lunatic” reflects this ancient belief in the moon’s power over the human mind. In 18th-century England, defendants could even seek a lighter sentence for crimes committed during a full moon, asserting that ‘lunar-induced lunacy’ was at play. Such beliefs offered a semblance of predictability in a chaotic world, allowing people to rationalise inexplicable behaviours and events. 

While modern science has debunked the direct influence of the moon on human behaviour, the allure of the full moon remains. Cognitive biases and the power of suggestion lead us to interpret and remember strange occurrences as moon-induced phenomena. The potent mix of historical context and contemporary culture ensures that the legends of werewolves, vampires, and the full moon will endure for generations.

moon photo

From classic literature to blockbuster films, the moon has often been depicted as a powerful force capable of altering human behaviour. Bram Stoker’s Dracula, for example, capitalises on lunar imagery to evoke a sense of dread and inevitability. Likewise, movies such as An American Werewolf in London and The Wolfman delve into the mystique of the full moon, attributing physical transformations and violent tendencies to its light. 

But it doesn’t stop there. Television series like Teen Wolf and Buffy the Vampire Slayer have also popularised the notion of the moon’s impact on human actions, often using the full moon as a backdrop for episodes laden with supernatural events. Even animation has its share of lunar lunacy, with shows like Sailor Moon drawing direct connections between moon phases and character transformations. 

Across the literary landscape, the moon continues to serve as a versatile symbol. Poetry often represents mystery, change, or madness, with works by William Wordsworth and Sylvia Plath exploring these themes. Moreover, contemporary novels such as Stephenie Meyer’s Twilight series employ the moon to enhance their otherworldly narratives. 

The enduring presence of lunar lunacy in popular culture demonstrates our fascination with the celestial body and its perceived enigmatic influence. While entertaining, this widespread representation also helps sustain the myths and misconceptions surrounding the full moon and human behaviour.

However, in contrast, recently – in the 2023 Movie ‘Hit Man’ – we get this exchange between the main characters:

And we’re mostly water, how could a full moon not affect you? Think about it.

[Gary] Well, technically, that makes no sense.

No, it makes sense.

[Gary] No. A phase of the moon has nothing to do with gravity. It has to do with shadows. A phase is just how much of the sun’s light we’re blocking on the way to the moon. You know, the gravitational relationship between the moon and Earth, these two planetary bodies, is fixed so the moon may look different throughout the month, but nothing is actually changing on Earth, you know?

full moon on cloudy sky during nighttime

Belief vs. Reality: The Power of Illusory Correlations

The illusory correlation is a powerful psychological mechanism. It explains why so many people believe the full moon affects human behaviour despite the lack of scientific evidence. Our brains are wired to make connections between unrelated events because we remember occurrences better than non-occurrences. This means when something odd happens on a night with a full moon, you’re more likely to remember it—and mistakenly attribute the weirdness to the moon. 

Moreover, cognitive biases play a crucial role. For instance, if you suspect that strange things happen during a full moon, you’re more likely to notice and remember instances confirming this belief. This selective memory reinforces the superstition, making it feel all the more legitimate. It’s a fascinating quirk of human psychology that has real-world effects. 

Believing in the power of the full moon can also provide psychological comfort. Superstitions often give us a sense of predictability in an unpredictable world. When things go haywire, attributing the chaos to the full moon can offer a form of reassurance, making us feel we better understand the mysterious forces affecting our lives. 

It’s noteworthy that this belief has permeated various aspects of society. Police often link full moons to spikes in aggression and crime, even though statistical evidence doesn’t support this correlation. Similarly, research has not validated that lunar cycles influence financial markets despite persistent claims in stock market folklore. 

Numerous meta-analyses reveal no significant correlation between the Moon’s phases and human behaviour. Yet the allure of the full moon’s supposed influence remains strong, capturing our imaginations and shaping our perceptions long after the moon has waned.

moon photography

The Psychological Appeal of the Full Moon Myth

Many find comfort in the idea that external celestial forces influence our behaviour. Assigning power to the full moon as a superstition can provide psychological reassurance by giving a sense of predictability in an unpredictable world. This predictability becomes a narrative, a story that helps us make sense of random or chaotic events. 

Cognitive biases play a significant role here. People who believe strange things happen during a full moon seek evidence to confirm their suspicions. This selective perception reinforces the belief, making it feel more real and impactful than it is. It’s a classic case of finding what you’re looking for, even if what you’re looking for isn’t truly there. 

Moreover, this myth is perpetuated by numerous tales from history and modern culture. Police records and anecdotal evidence often link full moons to higher instances of crime and aggression. However, rigorous scientific study does not support these observations, making them an example of illusory correlation. Yet, the storytelling continues, fuelled by anecdotal memories and pop culture sensationalism. 

Interestingly, scientific research does touch upon factors that may have given rise to these beliefs. In ancient times, when many people lived outdoors, and the full moon’s bright light affected their sleep patterns, it might have exacerbated mental illnesses, leading to erratic behaviour. Lacking modern street lighting, the increased visibility at night might have allowed for more nocturnal activities, including crimes, hence forging a cultural memory of the moon, which influences human behaviour. 

Ultimately, the appeal of the full moon myth lies in its ability to offer a simple explanation for complex human behaviours. It captivates our imagination and provides a semblance of control, even if just a comforting illusion. After all, it’s human nature to find patterns and meanings in the world around us, and the full moon serves as a perfect canvas for those projections.