List your top ten favourite songs and then ask yourself if they are overall happy or sad. This is what researchers at the University of California at Irvine did when they looked at 500,000 songs released in the U.K. between 1985 and 2015 and then categorized them by mood. “‘Happiness’ is going down, ‘brightness’ is going down, ‘sadness’ is going up, and at the same time, the songs are becoming more ‘danceable’ and more ‘party-like,’” Natalia L. Komarova reported to The Associated Press.

The researchers emphasize that they were looking for the trends in the acoustic properties and the moods describing the sounds. This doesn't mean to say that all popular songs in 1985 were happy and all popular songs in 2015 were sad. Songs with a low-happiness index in 2014 that were very popular were “Stay With Me” by Sam Smith, “Whispers” by Passenger and “Unmissable” by Gorgon City.

According to the research, the public does prefer happier songs even though more sad songs are being released. The most successful genres of music are pop and dance while rock has seen a “clear downward trend” since 2000. "So it looks like, while the overall mood is becoming less happy, people seem to want to forget it all and dance,” Natalia added.