You're driving to work, listening to your favorite radio station, when on comes Britney Spears' "Baby One More Time." By the time you pull into your office parking lot, you have, "Oh baby, baby" running through your head. You hum it at your desk. You tap it out on the conference table during your morning meeting. When five o'clock finally rolls around, your coworkers are shooting you the evil eye and you're ready to pull your hair out.
Why do songs get inextricably stuck in our heads? Experts say the culprits are earworms (or "ohrwurms," as they're called in Germany). No, they're not parasites that crawl into your ear and lay musical eggs in your brain, but they are parasitic in the sense that they get lodged in your head and cause a sort of "cognitive itch" -- a need for the brain to fill in the gaps in a song's rhythm.