Study: What Makes a Song Catchy?

Speaking of sonic branding. "There may be cognitive reasons behind a tune's appeal. Referring to a study done at Dartmouth College last year, Keith Duffy explained that MRIs show that a catchy song makes the auditory part of the brain 'itch,' and the only way the itch can be scratched is by listening to the song." --physorg

Earlier:
Computer scientists at the Massachusetts Institute of Technology have developed a computer program which they claim can accurately forecast where a song will appear in the charts.

The Echo Nest software has been developed by Brian Whitman and Tristan Jehan, who believe it will fundamentally change the way people choose the music they listen to.