By the light of the moon

PUBLISHED : Sunday, 04 October, 2009, 12:00am
UPDATED : Sunday, 04 October, 2009, 12:00am

If anything bizarre happened last night, don't panic - it's just the full moon. Or at least that's what lunar urban legends suggest.

For centuries, the moon has inspired countless stories. The ones we tend to remember are the scary rumours related to a full moon: murder tides and werewolves, for example, things that provide perfect campfire fodder.

But are all the myths unfounded? After all, the words 'lunatic', 'lunacy' and 'lunar' share the same Latin root. Past generations certainly believed there was a connection between the moon's phases and how people behaved. In 18th-century England, if a murder was committed under the full moon, the murderer was entitled to plead 'lunacy' to get a more lenient sentence.

We know the moon controls the tides by exerting its gravitational pull on water. It's also a fact that about two-thirds of the human body is water. Combine the two statements and there's a convincing argument that the Moon's gravity could affect human behaviour, too.

'I am neutral, but inclined to believe [lunar effects] may happen,' says Dr Tso Wung-wai from Chinese University's faculty of science. He said animals and plants that can sense the full moon may act in accordance to the lunar phases, but without any supporting, significant statistics, theses beliefs are groundless.

Among the supporters of the 'biological tides theory' is psychologist Arnold Leiber from the University of Miami, who released a groundbreaking book on the topic in 1978, The Lunar Effect: Biological Tides and Human Emotions. The book examines the link between the lunar cycle and homicide rates, and found the full moon marks a monthly peak in murders.

But eight years after the book was published, researchers from the University of Saskatchewan in Canada looked at around 100 studies and found 'no causal relationship between lunar phenomena and human behaviour'.

Yet the studies continue. A simple search on the internet will lead you to a long list of events that appear to be statistically related to the moon's phases: from birthrate, timing and gender of babies to post-operative bleeding; from the occurrence of arson attacks and road accidents to asthma attack and bladder problems. Some studies even suggest nutrient needs and meal choices may depend on the moon's waxing (moving towards full) and waning.

There are some interesting hypotheses as to how the moon influences us.

For example, Dr Michal Zimecki of the Polish Academy of Science suggests the moon's electromagnetic radiation and/or gravity affects immune systems by triggering the release of hormones and steroids.

And the Journal of Affective Disorders published an article in 1999 that suggested the lack of conclusions on lunar effect studies was caused by modern lights. It speculated that, before the invention of lamps, the light from the full moon would keep people awake and the resulting sleep deprivation 'would have been sufficient to induce mania ... in susceptible bipolar patients and seizures in patients with seizure disorders'. But modern lighting eases the lunar effect, making research impossible.

While he's not certain the moon affects us physically, Tso does believe it influences us 'via our mind', adding the sight of the beautiful full moon can put us in a romantic and/or happy mood.

As they follow a lunar calendar, the moon is particularly important to the Chinese. Farmers used to sync their agricultural events to its waxing and waning, and would consult the lunar calendar on even the most trivial decision.

The lunar calendar is still of sentimental and cultural significance: many people refer to it when picking 'lucky dates' for events such as weddings, funerals, moving house and the opening of a new business.

It seems we may never know the truth about the effect the moon has on us. But just in case, we should pay extra attention to what we say and do around Mid-Autumn Festival!