What's the Deal with Friday the 13th?!

Friday the 13th is one of the best-known superstitions in the Western world. For some, it's just another day on the calendar. But for others, it evokes an odd sense of dread - enough to postpone weddings, avoid air travel, or even skip work. Current estimates show that between 17 million and 21 million Americans believe that Friday the 13th brings bad luck. The word "paraskevidekatriaphobia" (the fear of Friday the thirteenth) was coined by the psychologist Dr. Donald Dossey, who told his patients that "when you learn to pronounce it, you're cured!" How did this specific combination of day and number come to be so feared?

The fear of the number 13 dates back to ancient times. In many cultures, 12 is considered a "complete" number: there are 12 months in a year, 12 zodiac signs, 12 apostles, and 12 gods of Olympus. Dr. Thomas Fernsler, an associate policy scientist in the Mathematics and Science Education Resource Center at the University of Delaware, explained that the number 13's unluckiness most likely "has to do with [13] just being a little beyond completeness." That belief was reinforced in religious texts and folklore. One popular Christian tradition points to the Last Supper, where Jesus dined with his 12 apostles. Judas, the disciple who would betray him, was the 13th guest. Dr. Phil Stevens, associate professor of anthropology at the University at Buffalo, said, "The number 13 became a problematic number because of the number of people at that table during that fateful event." In modern times, many buildings skip labeling a 13th floor, and some airlines avoid having a row 13.

Friday has long been associated with bad luck in Western culture. In The Canterbury Tales, written by Geoffrey Chaucer in 1392, Friday is presented as an unlucky day. Chaucer warned readers not to begin a journey or start a project on that day of the week. Some believe that this association with Friday is rooted in Christianity, as Friday is traditionally thought to be the day of Jesus's crucifixion. "Because Friday was the day of the crucifixion, Fridays were always regarded as a day of penance and abstinence. This religious belief spilled over into a general dislike of starting anything or doing anything important on a Friday," described Steve Roud, author of the 2003 book The Penguin Guide to the Superstitions of Britain and Ireland.

Combine the ominous power of the number thirteen with the suspect reputation of Friday, and you get what some call a "double whammy" of misfortune. There is also a historical theory: on Friday, October 13, 1307, Pope Clement V and King Philip IV of France ordered the mass arrest of the Knights Templar, a powerful religious and military order. Many were tortured and executed. While historians debate how much this event influenced the superstition, it is frequently cited as a possible origin of the date's legacy. This superstition continued into medieval times, when public executions were normally scheduled on Fridays, and condemned prisoners had to ascend 13 steps to reach the gallows.

The first concrete mention of Friday the 13th as a particularly unlucky day didn't appear until 1907 when Thomas W. Lawson published a novel titled Friday, the Thirteenth. In this book, a stock broker picks Friday the thirteenth as the day in which he sets about events to bring Wall Street to its knees. After the novel's success, stock brokers around the world allegedly refused to trade on any Friday the 13th. Then, in 1980, the horror movie Friday the 13th was released, launching a pop culture franchise that further cemented the day's eerie reputation.

Despite all of this lore, there is no scientific evidence that Friday the 13th is any more dangerous or unlucky than any other day. Studies on accidents, hospital admissions, and financial markets have yielded mixed results, with some even showing a slight dip in activity - possibly because people stay home out of caution. But still, the superstition persists. Some projections suggest that the date costs the American economy between $700 million and $900 million in lost revenues each time it occurs due to consumer reluctance to participate in normal economic activities. Dr. Simon Bronner, a professor of American studies and folklore at Pennsylvania State University, noted, "Psychologists treat [the fear of Friday the 13th] as real, but my sense is that... it's something to blame. I think it was a constructed belief." Regardless, the legacy of Friday the 13th remains influential in the collective cultural imagination.