Chord Ghosts

A sequence of sound waves cannot feel sorrow, yet minor chords universally make humans feel melancholy. When we listen to a piece of music, we are technically just receiving rapid fluctuations in air pressure against our eardrums. There is no physical entity suffering inside the instrument, nor is there any genuine grief encoded in the frequency of a note. Yet, the moment a string or a synthesizer dips into a minor progression, our bodies respond as if we are encountering a real, living presence in distress.

Music can activate our autonomic nervous system and cause profound physical reactions, such as shivers down the spine. A cross-cultural study published in PNAS revealed that music's emotional impact transcends cultures by evoking similar bodily sensations around the world, where happy music energizes arms and legs while sad tunes resonate heavily in the chest. How do invisible waves of air manage to physically ache inside our torsos? The answer lies in how we map sound to emotion, though researchers sharply debate the exact boundary between biology and culture in this process.

Some perspectives emphasize a strictly universal biological or psychoacoustic basis for major and minor emotion mapping, pointing to inherent acoustic qualities. However, extensive cross-cultural experimental data complicates this neat picture. In Western cultures, major chords and progressions are consistently associated with positive emotions, while minor chords and progressions are associated with negative emotions.

Basic emotions can certainly be communicated across cultures through music at least on a rudimentary level of recognition, but Western emotional concepts such as the major-happy and minor-sad distinction are heavily influenced by cultural background. When researchers test participants who have had no exposure to Western music, these individuals do not automatically link specific modes like major and minor with Western emotional concepts, provided that other emotional cues such as tempo, timbre, and loudness are kept constant.

Harmonic style alone has the ability to colour emotional expression in music, but only if it taps into the specific cultural connotations of the listener. Meanwhile, the exact extent to which acoustic properties like minor thirds universally mimic human sobbing versus relying purely on learned cultural signifiers remains debated across different empirical studies. What we do know is that acoustic roughness is an important acoustic phenomenon that typically renders sounds unattractive for human listeners, suggesting our ears are finely tuned to detect distress and discord in our environment.

When we experience a minor chord as sad, we are participating in a remarkable act of projection. Music is an auditory illusion that hijacks our social survival circuits, making us empathize with inanimate sound waves as if they were distressed living creatures.