Here's why Friday the 13th scares us

Jane Risen, a behavioral scientist at the University of Chicago Booth School of Business, has found that superstitions can influence even nonbelievers. In one 2016 study, Risen found that people who identify as superstitious and non-superstitious both believe a bad outcome is more likely when they've been jinxed. For example, they worry that stating they definitely won't get into a car accident will make it more likely to happen.

“Generally speaking, I find that this occurs because the bad outcome springs to mind and is imagined more clearly following the jinx,” she explains. “People use the ease of imagining something as a cue to its likelihood.”

, Risen's research also suggests that performing rituals that ward off bad luck can have surprising results. In a 2014 study, she found that some people use them even when they don't actively believe, and when tested, both types of people reported benefits from such acts.

It's difficult to pin down the origins and evolution of a superstition. But Stuart Vyse, an author and former of psychology at Connecticut College in New London, told National Geographic in 2014 that our fear of Friday the 13th may be rooted in religious beliefs surrounding the 13th guest at the Last Supper—Judas, the apostle said to have betrayed Jesus—and the of Jesus on a Friday, which was known as hangman's day. The combination of those factors produced a "sort of double whammy of 13 falling on an already nervous day," Vyse explained.

(Fonte: National Geographic - adaptado.)