The more repitious the music, the more "hook" it has and becomes popular.

While listening to a song, if a person can predict the next note based on repitiion, the person is more likely to prefer the song. It's the brain's lazy way of listening to something. And when the brain doesn't have to work, it goes into a different wavelength - trance state.

Similar to mantra repetition, which is histories "music" that quickly induces trances states.

Popular music has devolved into the same few notes being repeated over and over again. The brain latches on to it.the brain almost deadens while people mindlessly repeat the words or perform the associated dance (gangnam style anyone?). Sounds like the pied piper story.

Then, lyrics are easily inserted to a trancesd out brain. People freak out over binaural beats inserting non-productive, or negative affirmations. Yet the music industry already does this on a global scale. For a profit even!

Classical music, on the other hand, challenges the brain to work differently. Which is why people report better memory and flashes of wisdom when listening to Bach.