Pop songs trend sadder since the Sixties

data visualization mood of pop music
Detail of graph showing results of study on the changing mood of pop music (WNYC)

The mood of Top 40 pop songs has turned sadder over the past 5 decades, according to a study of tempos and major/minor keys by Glenn Schellenberg, professor of psychology and music at the University of Toronto. His results are charted below by John Keefe of WNYC in New York. Blue indicates songs in minor keys; the left axis marks tempo in beats per minute. [via Studio360]