Four key elements or x factors. ♪ >> reporter: number one, long and detailed musical phrases. ♪ entertain us >> reporter: number two, multipitch changes in the song's hook. number three, male vocalist. ♪ brown-eyed girl >> reporter: higher male voices making a noticeable vocal effort. ♪ living on a prayer >> reporter: using this formula, a list was compiled of the top ten catchiest songs of all time. "final countdown" by europe made the cut. so did the theme song from "baywatch," "i'm always here" by jamie jamieson. number two catchiest song of all time almost acted out as much as it i...