"Key to its success is its musical reiteration and the instructional nature of its lyrics, according to Dr Elizabeth Margulis, director of the Music Cognition Lab at the University Of Arkansas and author of On Repeat: How Music Plays the Mind. 'That’s a pretty repetitive song,” she says of Happy. “There is a catchy bit that expressly invites you to clap along. It is literally inviting you.' ...
She adds: 'The thing repetition really does is it captures the motor circuitry of the brain, so you have this sense the music is really pulling you along. It can make people feel really happy. There is something about having a song that is literally about being happy that is using this technique that makes people happy. It just feels good.' "
