What Do Scents and Sounds Have in Common?

The language of perfumery is thoroughly borrowed from music: top note, heart note, base note; a good perfume is ‘composed’, and the finest noses in the industry are still called ‘perfumers’ — literally, in French, parfumeurs, never mere ‘mixers’. This vocabulary is over a hundred years old — the perfumer Septimus Piesse published, in 1857, an actual ‘odophone’, a scale that assigned individual raw materials specific pitches, from the ‘deep bass’ of heavy musk and amber notes to the ‘high treble’ of mint and citrus.

For a long time this was taken as a pretty metaphor and nothing more. But experimental psychology has, over the past two decades, begun tracing this analogy in earnest, and has found remarkably consistent, cross-cultural patterns: in studies including work by Anne-Sylvie Crisinel and Charles Spence at the University of Oxford, participants reliably matched sweet, fruity scents to high pitches, and smoky, earthy scents to low ones — regardless of whether they had any musical training at all.

These so-called crossmodal correspondences are probably no accident, but a byproduct of how the brain organizes perception in the first place: the areas responsible for smell, for hearing, and even for perceiving brightness exchange far more information with one another than was long assumed. In synesthetes — people in whom these channels become entangled into conscious, often very precise color or shape perceptions — this effect shows up especially clearly; but in a weaker form, the studies suggest, we all carry a little synesthesia within us.

Long before Kandinsky, the French Jesuit priest Louis-Bertrand Castel had already designed, in 1725, an ‘ocular harpsichord’ (clavecin oculaire) — a keyboard instrument meant to display a colored surface with every key struck, built on the firm conviction that tones and colors could be set into a precise, almost mathematical relationship with one another. The device worked poorly in practice and was mocked by some contemporaries, but the idea behind it — a formal, reproducible translation between sensory qualities — kept returning in ever new variations, all the way to Scriabin’s ‘light keyboard’ almost two hundred years later.

Outside art and research too, the analogy has proven itself in practice: wine tasters reach quite naturally for musical terms — a wine is described as ‘harmonious’, as ‘discordant’, or as having a ‘long finish’ — and the food industry now experiments deliberately with background music to shape the perceived taste of food and drink: high, bright tones make sweetness taste sweeter, low, dissonant sounds heighten the impression of bitterness — a commercially applied confirmation of exactly the crossmodal correspondences Crisinel and Spence demonstrated in the laboratory.

Historically this connection was never entirely forgotten. Goethe’s theory of colors already sought correspondences between tones and colors, and Kandinsky explicitly described how certain colors triggered musical associations in him — yellow like a shrill trumpet, blue like a cello. That scent was usually missing from these considerations likely had less to do with the connection being weaker than with the fact that, in Western cultural history, smell was long regarded as the least ‘spiritual’ of the senses — too bodily, too animal, to stand seriously alongside eye and ear.

A project like Incense of Music, which has deliberately placed music and incense side by side since its very first evening in June 2015, is not, in that sense, working against a mere metaphor, but with a kinship anchored more deeply in perception itself than the phrase ‘scent chord’ might suggest. Whoever hears a tone and smells a smoke at the same concert brings both, consciously or not, into the same inner workshop — the place where perception has long since stopped sorting itself neatly by sense organ.