Someone actually did a study on earworms. Really. “Dissecting Earworms: Further Evidence on the ‘Song-Stuck-in-Your Head’ Phenomenon, James J. Kellaris, PhD, presentation to Society for Consumer Psychology, Feb. 22, 2003. It’s summarized at http://my.webmd.com/content/article/61/67505.htm. Be warned, though—it lists the top…