A population-level divide in human sensitivity to musical harmony

This study identifies a new, special class of subjects with a musically important type of auditory sensitivity. Participants (𝑁 = 59,897) in a gamified experiment listened to rapid, randomly ordered sequences of tones drawn from either a major or a minor triad and strove to classify what they heard. Performance in this major-minor tone-scramble task was strongly bimodal: a minority of “super-listeners” performed near ceiling, while most subjects (“non-supers”) performed near chance. We subsequently confirmed these results in a pre-registered direct replication (𝑁 = 25,758). We call the sensitivity required for high performance in this task “MM-sensitivity”. The heat map relating years-of-music-lessons to performance reveals (1) many super-listeners who never had any lessons, and (2) many non-supers whose years of lessons failed to increase their MM-sensitivity. Whether lessons increase MM-sensitivity in some lis- teners remains an open question. Importantly, super-listeners tend to take many more years of lessons than non-supers, implying that super-listeners tend to achieve higher levels of musical competence than non-supers. We argue that super-listeners may have greater sensitivity than non-supers to the qualities conferred to music by variations in scale.