Jennifer Ouellette in Ars Technica:
Hip-hop artist Childish Gambino (aka actor Donald Glover) made a splash in 2018 with the release of his Grammy-winning hit single, “This Is America.” With its stark, sudden shifts between choral melodies in major chords and menacing percussive elements drawn from the trap subgenre, the song constantly defies the listener’s expectations throughout.
That’s why “This is America” also tops the list of pop songs rich in so-called “harmonic surprise,” or points when the music deviates from listener expectations. This is according to a recent study published in the journal Frontiers in Human Neuroscience that analyzes Billboard hits from 1958 to 2019. And it’s no coincidence that the tune is among the most recent: the study also found that harmonic surprise in popular music has been increasing over the decades—a phenomenon the authors have dubbed “inflationary surprise.”