Metric Accent Affects Perception of Key Center in Pop-Music Chord Loops

Looped chord progressions in popular music can often be heard as having multiple plausible key centers. In a series of two experiments, we investigate meter’s role as an orienting force within these progressions. Both experiments presented listeners with a progression that looped the C major, F major, A minor, and G major triads, a series that could plausibly be heard in multiple keys. While the ordering of the triads remained constant across trials, we modified which chord began the loop, thus altering the placement of the initiating metric accent. In Experiment 1, participants heard the loop followed by a probe chord and were asked to rate the probe’s stability, a proxy for identifying a key center. In Experiment 2, participants saw a notated loop and were asked to select the most stable chord. We found a significant effect of metric position and chord identity, with participants rating metric accents and the C major triad as the most stable/centric event. We use these findings to create an algorithmic key-finding model that incorporates both pitch and metric information. Our study argues that metric position has a strong influence on key perception in popular music, challenging an inherited Western art music bias toward purely pitch-based understandings of musical key.