Most of us probably are familiar with Job, the Biblical character whose faith was deliberately tested with misfortunes.

First, marauders stole his oxen and donkeys, and killed his servants. Then, a wind swept in and collapsed his house, killing his sons and daughters. If that wasn't enough, he then was afflicted with painful sores from the soles of his feet to the crown of his head.

Things got so bad for Job that at one point, he even cursed the day of his birth. “Sighing has become my daily food," he wailed. “My groans pour out like water."

Job had it pretty rough, but he hasn't been the only one. Plenty of others throughout history have been plagued by successive calamities.

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There's Violet Jessop, who worked as a stewardess on the maiden voyage of the Titanic in 1912, and managed to survive the giant liner's collision in the North Atlantic with an iceberg -- only to take a job as a nurse on the Britannic, which sank in 1916 in the Aegean Sea.

And more recently, there's the bizarre story of English tourists Jason and Jenny Cairns-Lawrence, who were visiting New York City when Al Qaeda hijackers crashed two planes into the World Trade Center on September 11, 2001, and happened to be in London when the city's public transportation system was attacked by terrorists in July 2005, and traveled to Mumbai, India in November 2008, just in time to witness a third terrorist attack.

Newspaper writers took to calling them “the world's unluckiest couple."

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The idea that some people are destined to suffer chronic misfortune is so ingrained in our consciousness that there even have been songs written about it -- for example, “Born Under a Bad Sign," the blues classic recorded by Albert King back in 1967, in which the narrator complains that “if it wasn't for bad luck, I wouldn't have no luck at all."

But is there really such a thing as chronic bad luck, and if so, why do some people seem to be plagued by it?

Psychologists and academic experts in probability and statistics, who've studied the phenomenon of bad luck, provide a complicated answer. It is true that in the course of a lifetime, some people have a lot more bad things happen to them than most of us do. But that outcome can be influenced by a variety of factors, including random chance, the actions of other people, and individuals' own decision-making skills and competence at performing tasks.

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But in our minds, it all blends together and forms this thing that we think of as bad luck.

Rami Zwick, a business professor at the University of California-Riverside, points out that the idea of bad luck exists, in part, because most of us don't have a very good understanding of how the science of probability works.

“There is a difference between individual and aggregate experiences of people in a population," he explains. If you ask 100 people to flip a coin 100 times, for example, over time, you can expect that the average result for the group will be 50 heads and 50 tails. But within the group, individuals may have more heads than tails, or vice-versa. “If we think of heads as good and tails as bad, a few people will have a sequence of mostly good outcomes, and others will have mostly bad ones."

Friday the 13th? Unlucky for some.Corbis

In events where non-random factors such as decision-making and competence also come into play, it becomes a little trickier to determine exactly what causes what we often perceive as bad luck, Zwick says.

“When we think of someone like Steve Jobs or Bill Gates and ask why they're successful, the natural answer is to say that they're very talented," he says. “However, there are also many other people who are talented, who started businesses but were not successful."

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By looking at a sequence of decisions and outcomes over time, it may be possible to identify someone who repeatedly suffers misfortune because he or she makes bad decisions, or mistakes in execution. (Think of a car manufacturer that habitually scrimps on parts to keep prices down, leading to a reputation for shoddy products that drives consumers away.) But often, Zwick notes, it's difficult to filter out the influence of randomness.

The problem is that even when sequences of bad events are caused purely by random chance, our minds still crave an explanation.

“We believe in bad luck," explains psychologist and skeptical investigator Michael Shermer, author of the 1997 book Why People Believe Weird Things: Pseudoscience, Superstition, and Other Confusions of Our Time. He says that our ability to find patterns in masses of sensory data—a crucial skill that helped humans to survive and thrive—also tends to spot patterns in random noise, where none actually exist.

“Unfortunately, we have patternicity, but we aren't equipped with a good baloney detector."

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Indeed, British psychologist Peter Bentley, author of the 2009 book Why Sh*t Happens: The Science of a Really Bad Day, says that bad luck seems to afflict people who believe in it.

He notes, for example, that studies have shown that people who believe in bad luck will have more accidents on Friday the 13, traditionally perceived as an unlucky day.

“I think those that believe they suffer from chronic bad luck, are almost certainly those people who have a very ingrained mindset about how their life is going," Bentley writes in an email. “Some people learn from mishaps, they see the positive, even turn them into amusing stories. Others dwell on their perceived misfortunes, and start to perceive everything as yet another example of bad luck. Where one person may see missing a bus as an opportunity to take a look around a nice store, another may turn the experience into a depressing mope about how nothing in their life ever goes right."

But that subjective aspect of bad luck also makes it possible for people to rid themselves of the perception that they suffer from it. Zwick and colleagues, in an experiment detailed in a 2012 article in Journal of Experimental Psychology, found that subjects who experienced misfortune were more willing to take risks again, if they had washed their hands -- a traditional superstitious ritual that supposedly cleanses a person of bad luck.