If you’re a music fan, chances are you know what a song is. You may have sung ‘Happy Birthday’ to your friends, or danced around the living room to your favorite tune. You probably know that songs tend to be short, often in the three-minute range, and contain words. Most songs have a form that includes verses, and the chorus—a repeated phrase at the end of each verse. Some songs even have a meter, or beat. But do you know what a song is, in a deeper sense?
The word “song” can refer to any musical work that incorporates lyrics. But it also can be a specific type of music, such as a folk song, an opera, or a pop hit. And it can be sung, either without accompaniment (a cappella) or with instruments. It can have a simple structure of one or two verses and a refrain, or a more complex one with multiple verses and several different choruses. It can have a meter or beat, but it doesn’t have to.
A corpus of ethnographic texts on music in all societies and a discography of audio recordings have revealed that musical behavior is universal, but varies in a set of dimensions—formality, arousal, religiosity—more within than across societies. These dimensions reflect the complexity of music’s power laws, and their impact on the social world they help to shape. For example, excerpts of songs high on formality resemble ceremonial events, with large audiences and many singers; those low on formality describe informal events, such as people singing to themselves or their children. Similarly, the arousal of songs varies considerably—examples high on arousal are lively works with loud instrumental accompaniment and a pronounced rhythm; those low on arousal are calmer, more relaxed.