The end of this week—June 21—marks the summer solstice, a day that is good to do a lot of surprisingly specific things, according to the Farmer’s Almanac. Whether it’s cutting your hair to “retard its growth” or washing wooden floors, Sunday is the day, it says, based on the moon’s astrological position.
The Almanac also tells us it would be a good time to perform demolitions, if you had any of those planned. But these are just suggestions, after all. Beliefs based on the moon’s influence our lives and behavior has been examined from many angles over time, the most obvious example being the etymology of the word “lunacy.”
Meanwhile, cases of lycanthropy—or the belief that the full moon transforms one into a werewolf—were documented as late as the 1970s. And, earlier this year, a team of researchers at the Queen’s University in Canada sought to explore whether psychiatric episodes and emergency department admissions were in any way related to lunar cycles—and they were far from the first ones to do so. The Queen’s University researchers, led by Varinder Parmar, wrote that the belief in lunar impact might be “a cultural artifact, left over from the time before artificial lighting.”
“The full moon provided an increase in the amount of nighttime illumination and caused a significant sleep disturbance as a result,” wrote Parmar et al in their study. “Recent research has shown that sleep disruptions of as little as 1.5 hours from baseline can induce mania and seizures in vulnerable people.”
But even that question—whether a full moon causes sleep disturbance at all is a recurring one—said Martin Dresler, a neuroscientist and sleep researcher at the Max Planck Institute of Psychiatry in Germany. Dresler and his colleagues have all been asked “the sleep question” at some point or another—or more precisely, why the full moon “makes” one sleep badly.
More than 2,000 nights and 1,265 slumbering volunteers later, Dresler and his colleagues announced their answer Monday: it doesn’t. Instead, Dresler attributes the belief to selective memory.
“You only remember the times you woke up and saw the full moon, and forget all the times you woke up and you didn’t see the full moon,” Dresler told The Daily Beast. “That’s really the best explanation for the notion the moon influences sleep.”
He said the other explanation was the “file-drawer” phenomenon in research: the tendency of researchers not to bother with publishing negative or inconclusive findings, leaving data to gather dust in the…well, file drawer.
And there are others, like Glenn Wilson, a visiting professor of psychology at Gresham College in the United Kingdom, who also keep up with research on whether the moon influences behavior. Several years ago, he was even contracted by tequila manufacturer Jose Cuervo to do a scientific review of literature relating to moon and behavior as Cuervo was promoting full moon parties in Thailand.
“One thing seems to be the observation of the moon’s influence on our tides,” he said in a lecture at Gresham College in March. “Since humans are 80 percent water, people say, then the water in our brain must be similarly affected.” But as he points out, the moon’s effect on our body water is minimal and the new moon has exactly the same gravity as the full moon.
Despite the evidence, there is a tendency for many people to believe in the moon’s impact; the reasons for which vary, experts say.
For those 4 million who read the Farmer’s Almanac daily—some of whom take it very seriously—it is to do with a mixture of tradition (the publication has existed since the 1800s) and good experience with following its advice, said Sandi Duncan, the managing editor of the almanac. But bigger decisions that used to be made based on where the moon is positioned aren’t made anymore.
“People would actually have surgery based on where the moon was, as the moon’s astrological position supposedly correlated with a certain part of the body,” said Duncan. “I don’t remember if it was that you were supposed to have surgery say, on your feet, when the moon was in the position corresponding to feet, or whether that was when you weren’t supposed to.”
Still, she added, “we [Farmer’s Almanac] don’t offer this information anymore, you should have feet surgery when your doctor says you should have feet surgery.”
But unless one is rushing to the nearest pharmacy to stock up on massive amounts of Ambien to prepare for a full moon, or really using its position to determine when to get foot surgery, Duncan argued that like with horoscopes, believing in the moon’s influence—taken with a grain of salt—can’t really hurt.
“If you want to give a chance, maybe it will work for you, maybe not,” said Duncan. “But there’s no harm.”
However, Gresham College’s Wilson is not so sure. In his lecture he cited astrologer Joan Quigley’s influence on former President Ronald Reagan at a time where “he had his finger on the nuclear button.”
Still, for those who feel less like pinning world affairs on lunar and planetary movements, they can start smaller and seek cosmic help for their to-do lists. The fishing calendar, for example, warns us that this Sunday is a “poor day,” meaning “fish will either steal all your bait or will not even touch your line.” So maybe consider bowling instead, or take your chances. In the end, there’s only choice and circumstance.