http://www.sciencemag.org/news/2017/11/what-makes-happy-song-chances-are-it-has-more-seventh-chords http://www.sciencemag.org/news/2017/11/what-makes-happy-song-chances-are-it-has-more-seventh-chords
Major and minor sevenths were both more prevalent in happier songs http://rsos.royalsocietypublishing.org/lookup/doi/10.1098/rsos.170952, the researchers report today in Royal Society Open Science. But there were some regional differences: Songs from Asia and Oceania tended to be more positive than songs from North America, whereas songs from Scandinavia tended to be more negative (thanks to the popularity there of darker genres like power and death metal, the researchers say). The study also found an overall decrease in positive music and lyrics, which peaked in the 1950s. But those good vibes may be making a comeback—since 2010, the “happiness score” of popular songs has been on the rebound.
