Friday The 13th Isn't Really Unlucky, But You Still Might Have Friggatriskaidekaphobia

Friday the 13th isn't any luckier or unluckier than any other day on the calendar ... knock on wood.

Still, that doesn't stop some poor souls who are certain that the day is going to result in bad luck and bad news.

In fact, a study by the Stress Management Center and Phobia Institute in Asheville, North Carolina, suggests an estimated 17 to 21 million people in the United States are affected by a fear of this day.

The official phobia is called, depending on which shrink manual you're afraid to read, "friggatriskaidekaphobia" (Frigga being the name of the Norse goddess for whom "Friday" is named and triskaidekaphobia meaning fear of the number thirteen), or "paraskevidekatriaphobia."

Either way, just learning to pronounce it is part of the cure.

However, research into the people who suffer a fear of Friday the 13th suggests that these poor souls are so paralyzed by fear that they avoid their normal routines in doing business, taking flights or even getting out of bed.

Although it's not good to let fear dictate your life, it's hard to fault when it gets you one to three additional three-day weekends per year.

This year, there's only one Friday the 13th on the calendar. That might seem like good news to those in fear of the day, except when you think that it comes eight days before the supposed end of the world.

Supposedly, an estimated $900 million is lost in business on Friday the 13th, especially on the stock market. However, Dr. Glenn Pettengill, a professor of finance at Grand Valley State University in MIchigan, doesn't take much stock in that claim.

Pettengill says the research shows that there's no proof that Friday the 13th has any more of an effect on the stock market than Tuesday the 10th or Monday the 25th.

In fact, he says that Thursday the 13th would be more likely to be a bad day because it falls during a natural mid-week, mid-month slump.

So why do people fear Friday the 13th instead of, say, Thursday the 13th? It's hard to say exactly why because the perception that this day is particularly unlucky is relatively young.

Although the number 13 has been considered bad news for centuries, and Friday also had a bad reputation, they were only combined into one Reese's peanut butter cup of superstition in 1869 in a biography of composer Gioachino Rossini that read, at one point: Rossini was surrounded to the last by admiring and affectionate friends; Why Friday the 13th Is Unlucky

Dr. Richard Brown, a neuroscientist who works at the Exploratorium in San Francisco, says the reason humans develop superstitions like the one surrounding Friday the 13th is a side effect of the way our noggins are wired.

"By nature, we're looking for causality and pattern," he told AOL Weird News. "Just as there are visual illusions, we have cognitive illusions."

Brown says superstitions differ by cultures, but they are so ingrained that even people who accept that they are nonsense in their heads still act irrationally.

"A while back, we did an admittedly unscientific study where we had people challenge their superstitious beliefs," he said. "We had people spill salt and not throw it over their shoulder and make a prediction about the future without knocking on wood. No matter how many of these superstitions people challenged, there was one they wouldn't do."

For that reason, it's entirely possible that you are still quaking in your boots about what may or may not happen today. Well, to put you at ease, here is a list, courtesy of Daily Brew, of some positive things that happened on previous Friday the 13ths:

• On August 13, 2004, the opening ceremonies of the Athens Olympics took place without a single serious mishap

Well, maybe Friday the 13th is unlucky after all.