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By their very definition, according to Merriam-Webster, superstitions are nonsensical: “A belief or practice resulting from ignorance, fear of the unknown, trust in magic or chance, or a false conception of causation.” In other words, a superstition is “an action that is inconsistent with science,” Stuart Vyse, a psychologist and professor at Connecticut College, told CBS.

Still, for a set of supposedly irrational beliefs, superstitions have a surprisingly large following. An estimated 17 to 21 million people in America. are afraid of Friday the 13th, 74 percent of those in the U.K. say they knock on wood to avoid bad luck, and 13 percent of Americans cringe at the sight of a black cat.

So why does more than 50 percent of the country, as per a recent Gallop poll, consider themselves superstitious? And why, even when people don’t truly believe superstitions can impact our fate, do they continue to participate in them?

For one, superstitions have been ingrained in our lives since the very beginning. “People teach them to us when we’re young,” Vyse, the author of Believing in Magic: The Psychology of Superstition, told LifeHacker. “They’re part of the lore of any culture. The basic process of socialization is a major part of it.”

Secondly, they can be a soothing control mechanism. “We live in a world where you can’t always control the outcome,” says Vyse. “Superstitions tend to emerge in those contexts. You do everything you possibly can to ensure that things will work out.” Together, those two factors have made a very real impact.

“One of the interesting things about superstitions is their seemingly arbitrary nature,” Tom Gilovich, a psychology professor at Cornell University, told CBS. “Like, why 13? Why black cats? Why can’t you walk under that ladder? It has no rational bearing. Yet somehow you feel like you’re tempting fate, and the outcome, a bad outcome, that could befall you is going to be worse because you deliberately did something that people say you shouldn’t do.”

Evolution might also be at play here. “A prehistoric human might associate rustling grass with the approach of a predator and hide. Most of the time, the wind will have caused the sound, but if a group of lions is coming, there’s a huge benefit to not being around,” Kevin Foster, an evolutionary biologist at Harvard University, told the New Scientist.

Speaking of the benefit of superstitions, many of the ones that indicate good fortune—a lucky penny or a trusty charm bracelet—can have their perks. In one study published in Psychological Science, researchers gave golf balls to all of their participants and told half that their golf ball was lucky. The subjects with the “lucky” golf balls made 35 percent more successful putts.

“Feeling lucky gave them a better sense of self-efficacy (a belief in your own competence), which then enhanced their performance with the golf playing,” Matthew Hutson, science writer and author of The 7 Laws of Magical Thinking, told LifeHacker about the study. “The same researcher did several other experiments where she crossed fingers for them or the subjects had lucky charms on them. Their superstition helped them perform better on certain cognitive tasks, memory games, and physical tasks.”

So go ahead and wear your trusty charm bracelet, and ditch your fear of Friday the 13th. It could bring you a little bit of—dare we say—luck.

MORE: Here are some pretty bizarre things that happened on Friday the 13th.