Measuring the Evolution of Contemporary Western Popular Music : Scientific Reports : Nature Publishing Group | cross pond high tech | Scoop.it
Researchers in Spain used a huge archive known as the Million Song Dataset, which breaks down audio and lyrical content into data that can be crunched, to study pop songs from 1955 to 2010.

A team led by artificial intelligence specialist Joan Serra at the Spanish National Research Council ran music from the last 50 years through some complex algorithms and found that pop songs have become intrinsically louder and more bland in terms of the chords, melodies and types of sound used.

.../... (Abstract from Reuters available at http://www.reuters.com/article/2012/07/26/us-science-music-idUSBRE86P0R820120726)