Why you don’t howl at the moon

Abstract: Why claims of lunar-induced lunacy are bollocks…

One of the most fascinating people I ever met when I started in radio was the station’s late night presenter. He was something of a wistful, so-called New Age character. When I first met him his head was buried in his hands as he bemoaned the fact that it was a full moon that night. “What difference does that make?” I asked him. He gave me a tired smile and shook his head, “‘Cos it brings out the crazies.” I remember thinking, “Hey, it’s the 1980s! Do people still believe that rubbish?” [I may have used another word.]

It seems they did – and still do. And not just in a silly, breathless Twilight-Saga-kiss-the-werewolf-and-he-turns-into-a-strapping-young-hunk kind of way. But rather in a furiously nodding, yes-there’s-definitely-something-in-it kind of way. So I’d be failing in my duty as Sceptic Guru if I didn’t strap on my goggles, grab my trusty torch of science, and shine it at the moon.

Full moon madness
First of all, we must dust off all the ancient folklore around the moon and its supposed effect on human behaviour. Given its prominence in the night-time sky, it’s no surprise that since recorded history, across diverse cultures, the moon has played an important role in shaping everything from superstition to religious belief to science.

Of all the phases, a full moon – when the moon is on the opposite side of the Earth from the Sun and appears at its brightest – is the one that sparks the most excited old wives’ tales; the most common of these being that a full moon induces madness. It is from this belief that we have the term ‘lunacy’.

This belief remains popular today, even in the face of modern science. And I have to admit that the logic behind it is…well…quite logical. It goes a little like this: the position and phases of the moon influence the tides of the seas, which are large masses of water. The brain is 80% water, ergo the moon must affect human behaviour in some way.

Now, to say that the moon influences the tides is a little simplistic. The reality is that the tidal activity of the Earth’s oceans is the result of a complicated interplay between the Earth’s rotation, the positions of both the Sun and the Moon, and bathymetry – the depth and structure of the ocean floors.

However, for the sake of the argument…yes, the moon does provide a gravitational tug on the Earth’s oceans and seas – in fact, it pulls on the solid ground as well – but only the water in the oceans and seas move in response to the gravitational pull because it is unbounded.. And here is the critical difference between the watery depths of the oceans and the water found our brain: the water in the human brain is bound by the body, and so isn’t affected by the gravitational pull of the moon.

“It’s in the newspaper so it must be true…”
So if the moon can’t physically affect the human body, what about all the evidence in the popular media about increases in criminal activity, emergency room admissions, domestic abuse, and even casino payouts during a full moon?

Well, first of all, the term ‘popular media’ gives us a hefty clue. It wouldn’t be ‘popular’ if it didn’t pander to fashionable sentiment. It’s why most newspapers don’t have a science section but still publish horoscopes (a bone of contention for all science journalists).

Secondly, any supposed ‘evidence’ is purely anecdotal. Furthermore, it is influenced by what psychologists call confirmation bias and communal reinforcement. Confirmation bias is the tendency to select information as evidence to support a preconception. It’s why supporters of an opposing football team always seem hairier and more ugly than you – based on your selection in the crowd of an individual that seems to embody that trait. If you find that the opinion is shared by your fellow supporters, you may find your own opinion being reinforced – despite it not being based on any empirical evidence whatsoever. This is understandable. After all, you’re part of community…and, well, you can see where this is going…

In brief: if brought up with a belief – rooted in folklore and perpetuated by the popular media – that there may be a link between the moon and madness, people focus on events that support that belief, egged on by similar sentiment within their communities. So police report higher incidences of crime during full moon; emergency room staff report higher admissions during the same period; and so on. This is then picked up by the popular media, who report it; and so the cycle continues.

Shedding light on the dark side of the moon
And what does scientific research say on all this ‘evidence’? Numerous independent studies and meta-analysis studies of claims and reports have come to the same clear conclusion: there is no evidence of any causal link whatsoever between the phases of the moon and human behaviour.

But the blinding realities of science don’t seem to stop those who continue to dabble in the dark recesses of pseudoscience – just are there are still those who invoke physics in the support of their belief in tales of full moons and ghosts and demons. You might find them lurking in places like the Spiritual Research Foundation.

Go and have look. But don’t forget your flashlight.

Originally published in the December 2012 edition of Guru magazine.