Pop music is getting sadder, slower, and more sophisticated, according to a new study published in a psychology journal. Researchers analyzed Top 40 hits in Billboard from the mid-60's through 2010 and discovered that popular tunes have increasingly been written in "minor modes"—which associate with darker emotions, reports Pacific Standard. The top songs also have gradually become lengthier and slower in tempo, and their messages aren't as straight-forward.
“As the lyrics of popular music became more self-focused and negative over time, the music itself became sadder-sounding and more emotionally ambiguous,” say the researchers. They also pointed out a compelling similarity with the evolution of classical music, although on a much shorter scale. “Throughout the 17th and 18th centuries ...pieces tended to sound unambiguously happy or sad. By the 1800s, and the middle of the Romantic era, tempo and mode cues were more likely to conflict."