If you carried around a good-luck charm as a kid, you might have noticed that you sometimes performed better on tests or scored more goals at soccer practice. This extra fortune may have just been in your head, but psychologists say that doesn't matter. In fact, that's precisely why your lucky charm worked in the first place.

As the SciShow's Hank Green explains in the video below, talismans do inspire confidence (if not magic), as well as self-assurance. In fact, simply perceiving yourself as a lucky person can lead to success, as self-fulfilling prophecies are way more potent than four-leaf clovers or horseshoes.

This phenomenon is backed by science. Take, for instance, a 2010 study in which German psychologists challenged 28 university students to a game of mini golf. Participants who were informed they'd been given a "lucky" ball ended up performing 35 percent better than the subjects who were told they were using ordinary equipment.

The same researchers then did a follow-up study of 40 students who admitted to having lucky charms. They asked them to take a memory test either with or without the charms. Those who had their totems scored better on the test—and had higher confidence.

Learn how the psychology of luck works—and how to make your own—by watching the video below.