The authors of the study, music psychologist Prof. Dr. E. Glenn Schellenberg from the University of Toronto Mississauga and sociologist Prof. Dr. Christian von Scheve from Freie Universität Berlin, working together in a joint research project at the Languages of Emotion Cluster of Excellence, found that during the past decades the songs in the American charts have increasingly often been composed in a minor key and their pace has often been slow. In fact, the percentage of minor scales in the songs doubled in the decades between the 1960s and today. In the 1960s, 85 percent of the songs – such as the hits "Help" or "She loves you" by the Beatles – were written in a major key, while today only 42 percent are. Most listeners associate the slow tempo and minor keys with sadness and a fast pace and major keys with happiness.
"Just as the lyrics of pop songs have become more self-referential and negative in recent decades, the music has also changed: it sounds sadder and emotionally more ambivalent," explained Schellenberg and von Scheve in their recent study. They conclude, "Listeners of popular music today like emotionally complex pieces." The development of popular music during the past 50 years has amazing parallels to that of the 17th to 19th century. "During the 17th and 18th centuries, the music that dominated was clearly happy sounding or sad sounding. During the Romantic Period, there was an increasing tendency toward different emotional nuances in one composition." That makes it possible to express a greater scale of emotions in a single piece of music.
The researchers suggest cultural developments giving more attention to emotion as a possible explanation for the increasing tendency toward sad music. According to the sociologist von Schreve, "Emotions are increasingly becoming the focus of our self-understanding. In addition, ambivalence is an important facet of modernization. Both lead to a reflexive approach to emotions, which is reflected in popular music." Von Schreve thinks it would be incorrect to conclude that individuals are becoming increasingly sad, just because they listen to or compose that kind of music. "I would suggest it means that sadness can even be enjoyed," said von Schreve.
The study examined more than 1,000 songs, each of which appeared during the last five years of a decade (1965–69, 1975–79, 1985–1989, 1995–1999, 2005–2009) and at the end of the year was among the top 40 in the "Hot 100" charts of the Billboard popular magazine. Each song was analyzed according to female or male artist, length, tempo, and key.