【音楽の進化】「歌は世につれ」と言うけれど

A quantitative analysis of songs in the Million Song Dataset reveals a number of emerging patterns in the evolution of contemporary popular music. The study, published in Scientific Reports, suggests that over the past 50 years pop songs have become louder, their pitch has become more restricted and their timbre more homogenized.

Like language, music is an important form of cultural expression, but the long-term variations of the underlying patterns remain poorly understood. Joan Serra and colleagues studied the Million Song Dataset, which includes descriptions of the pitch, timbre and loudness of musical recordings from 1955 to 2010, spanning a variety of genres, from pop and rock to hip hop. They report several statistical patterns and metrics characterizing the general usage of pitch, timbre and loudness in contemporary western pop music. Many of these patterns have remained stable over a period of more than 50 years, suggesting a tendency towards conventionalism in the creation of this type of music. But the authors also observed three important trends in the evolution of popular music: the restriction of pitch sequences, the homogenization of timbre and an increasing average loudness.

The authors suggest this means that an old tune rerecorded using modern techniques that allow for increased loudness and with slightly simpler chord progressions and new instrument sonorities could be perceived as novel and fashionable. The development of further historical music databases could allow the quantification of major transitions in the history of music and the discovery of more subtle evolving characteristics of particular genres or artists.