Take, for instance, the number 13. It was considered unlucky in ancient Norse, Maya, and Christian traditions. This superstition persists today. Many modern hotels and tall buildings don’t have a 13th floor. Or maybe you’ve heard that you shouldn’t walk under ladders. This belief dates back to the ancient Egyptians, who viewed triangular shapes, like pyramids, as sacred. Since an open or leaning ladder makes a triangular shape, passing beneath one was —and still is—considered unlucky.
Not all superstitions involve misfortune, though. Finding a penny, hanging a horseshoe, or knocking on wood are thought to ward off bad luck. No matter the superstition, they were all created to serve the same purpose, says Saucier: “By avoiding black cats or throwing salt over their shoulders, people were able to believe they could better control what happened to them.”