When slurping on “hot dry” noodles from a dingy, styrofoam box, a lot of senses come together to create the full experience of the meal. First, you see the bright red vegetables and thick sauce coating the noodles. Then there’s the fragrant aroma, followed by chewiness and slipperiness accompanying each bite. And then comes the taste—an addictive, mildly-spicy-and-sweet sensation that prompts second and third bites.
Those are the four senses most people think of when eating a meal. But over the years, researchers have found that a fifth sense matters: sound—from dinner party chatter to bees buzzing around a picnic—can act as a sort of “sonic seasoning.” When noise is added to an eating experience, it can affect the levels of sweetness, bitterness, or sourness people perceive from their food. Scientists have experimented with single tones, testing how listening to particular frequencies and pitches can make affect the overall sensation one has when dining.
One of the leading researchers in the space is Charles Spence, who runs the Crossmodal Research Laboratory at Oxford University’s experimental psychology department. In a 2010 study, Spence’s team found that in addition to connecting different pitches of sound with our basic tastes (sweet, bitter, sour, salty), their 34 test subjects also consistently matched particular tastes with instrument characteristics, such as pairing bitterness with brass.
They used that data to develop a hypothesis: they could change someone’s perception of food by playing them music that had some of those pitches and instrument characteristics. The team chose a number of 40-second music tracks they believed to possess a sweet or bitter “connotation,” and played them for 20 subjects who were asked to eat some cinder toffee while listening, and then give their thoughts on how the toffee tasted. The study proved their hypotheses correct: the music they expected to convey sweeter notes made the toffee taste sweeter, while the predicted bitter tracks made the toffee more bitter.
It’s still not clear exactly how it all works. There’s a rich scientific literature on “tasting sound” when it comes to synesthesia, a rare neurological phenomenon whereby stimulation of one sensory pathway causes an involuntary experience in a second pathway. For example, in a review paper, Spence describes a Russian who reported experiencing the taste of borscht upon hearing a 50 Hz tone but would experience a repulsive, briny pickle when he heard a 3,000 Hz tone. Spence believes that while synesthetes may experience particularly nuanced sensations, there may be certain aspects of synesthesia that we all possess—such as a connection of sweetness to higher pitches and bitterness to lower pitches.
There are other theories: Felipe Carvalho, a sound designer and Ph.D. candidate at Vrije Universiteit Brussel, says that sound parameters like pitch, loudness, and timbre “are naturally congruent with specific taste or flavor attributes. Some of these associations may be more physiologically driven, whereas others may be more related to our culture and life experience.”
Whatever the underlying explanation, in Spence’s eyes it’s only a matter of time before linking sound and taste leaves the lab. He’s already taken his own work into the field by, for example, collaborating with modernist chefs like Kitchen Theory’s Jozef Youssef in designing high-brow, pop-up tasting events, and the Fat Duck’s Heston Blumenthal in preparing dishes that specifically try to unify auditory and olfactory senses. Soon enough, he thinks, big brands will latch on.
In 2014, the late food writer Joshua Ozersky dismissed the idea of marrying sound and food as a gimmick—”as unnatural as trying to thumb-wrestle and defecate at the same time.” But Spence and others feel they’re on the verge of proving him wrong—using chocolate.
In a paper recently published in Appetite, Carvalho and Spence announced that they’d designed music to effectively amplify the sensation of chocolate’s creaminess and sweetness. The soundtracks, Carvalho writes, were formulated on the basis of two pools of previous research. The first is the “bouba-kiki” effect, which describes the phenomenon that people tend to associate round or smooth auditory cues with “bouba”-like words, and sharp or rough auditory cues with “kiki” like words. (In a 2015 paper, subjects reported that subjects perceived the name “Molly” as a bouba sound, while “Kate” was associated with kiki.) The second is a body of work that has found certains characteristics of an instrument’s sound can be mapped to audio-tactile metaphors. A flute, for example, is typically considered “smooth” or “blunt” while a violin is “rough” and “sharp.”
Carvalho recruited musicians to compose songs built around these observed phenomena. Then he compiled them into a playlist, each song paired with a chocolate as a “multisensory seasoning” for the sweet. The project, titled “Sound of Chocolate,” is available for purchase online and at collaborating chocolatiers in Belgium. Beyond just experiencing enhanced chocolate, customers can learn about the scientific process behind the sound-taste pairings through an accompanying booklet.
Meanwhile, Caroline Hobkinson, a London-based experimental artist whose primary medium is food, is working with Sainsbury’s, a supermarket chain in the UK, to start to bring sonic seasoning to a wider audience. There, she has orchestrated a system where QR codes would be placed next to samples of cheeses at the supermarket. When scanned, the code downloads a mp3 file of a soundscape designed to enhance the experience of consuming the specific cheese.
Staccato sounds, Hobkinson says, make you “much more aware and much more perceptive.” By heightening the sensation of sinking your teeth into nibs of calcium lactate, the sound further draws out the sharpness of the product. In addition, “with a staccato noise, the drumming noise, it really brings out texture in cheese,” she says. “So any time you have the salt crystals [in cheese], the fast repetition, it really brings out the crystals. But if you have something constant or melodious, you’re not aware of them.”
Spence hopes his research will go beyond just the experiential hedonism of making your eggnog taste sweeter; he’s now trying to figure out how to use sonic seasoning to improve public health. Previous experiments have found that when higher-pitch frequencies are played for someone while they drink coffee, it tastes noticeably sweeter; lower-pitch frequencies made it more taste bitterer. With further research, there could be a foreseeable future where companies, for example, sold reduced-sugar products accompanied by a particular sound that makes them taste full-sugar.
However, Spence acknowledges that a lot more testing is needed. He also worries that marketers could take it too far, too quick—it’s easy to imagine a weight loss marketing campaign for “sound as the new sweetener” before it’s been proven out.
Whether or not sonic seasoning will prove a health benefit, Hobkinson thinks that in a few years, thanks to our growing accustomization of technology, sonic seasoning could slowly be introduced to the masses. Consider your morning coffee run: “Starbucks wants to know your name anyways, so they can send you just a little sound thing every time” says Hobkinson. “Like, ‘Hi, your coffee’s ready, and here’s today’s sweetness preference,’ and you have your track, and you can listen to it while you sip. You can even have it loud or just quietly. And it will taste sweet.”