“Sound is a forgotten flavour sense.” Food scientist and experimental psychologist Charles Spence definitely hit the nail on the head with that observation. Our memories of food usually include its colour, taste, and texture. However, the accompanying sound, whether during the process of cooking or eating, often allows us to make clearer recollections.

Now, play this video on mute – it feels like something feels missing, doesn’t it?

As morsels of fresh seafood and vegetables are dipped into tempura batter, an unmistakably unguent sound gently whispers in your ear, but only if you are standing close enough. Each batter-coated slice enters a bath of golden oil, producing mouth-watering crackling that intensifies with every second. And when you take your first bite, the crunch that resonates from the inside of your mouth, all the way to your brain, sends warm tingles throughout your body.

And it’s not just with fried food – imagine the gurgle from a pot of soup, as if demanding to be stirred; the sizzle of sauce when it hits a red-hot pan to slather the eagerly-awaiting meat within; or the almost-metallic tinkle you hear when you run the sharp edge of your knife across the top of a freshly-baked loaf of sourdough bread, followed by a familiar crunch as said knife slices through the crust to reach its warm, pillowy interior.

All these sounds effortlessly whet appetites and stimulate your desire for food. As the head of Crossmodal Research Laboratory at Oxford University, Professor Charles Spence has spent his career studying the link between the human senses. He believes that enjoying food is an all-round experience that involves not only the mouth, nose and eyes, but also the ears.

For years, Spence has been researching the connection between sound and food. “Our brains are all the time trying to pick up correlations in the environment,” he says. It could be that sound acts as an indicator for texture, and therefore, affects the way we perceive quality. People give carbonated drinks higher ratings if the fizzy sound is more prominent, and rate an apple higher if it makes a satisfying snap when bitten into.

SOUND & TASTE: A LOVE STORY

In Chinese culture, there is a belief in “the harmony of sound and taste”, which shows that even long ago, food and sound already shared an unmistakeable bond. According to recent studies on dietary behaviour, the information that we get from sounds can be divided into two categories: interoceptive cues (from the interaction between the person and the food, such as sounds made from chewing, swallowing, preparing or cooking) and exteroceptive cues (mainly external sounds like ambient noises and background music).

Midnight Diner is one example of how sound plays a huge part in affecting the way you perceive food. This hugely popular Japanese TV series revolves mainly around food – the intro includes a close-up process of preparing tonjiru (miso soup with pork) – and each episode features a specific dish that is often cooked on-screen, tantalising viewers who choose to watch the drama during the wee hours of the morning.

The tendency of people leaning towards interoceptive cues as the deciding factor for freshness or taste might also explain why cooking shows still reign supreme on YouTube, even during the influencer era where content quality has become somewhat diluted by pranks and “tea” commentaries. Watching videos on channels like Bon Appetit (5.8 million subs), Gordon Ramsay (17.1 million subs) or Maangchi (5.4 million subs), you’ll notice the common denominator: the extra focus on the sound produced by the food. Take the video below, for example: you hear the scallions being sliced into perfect little rings, the darkened skin of the squid being peeled, and the marinade being mixed in a metal bowl. And this is what keeps viewers coming back.

SINGING A SONG OF FRIED CHICKEN

Whether we are consciously aware of it or not, there is a “soundtrack” to the food we eat. In Spence’s book, Gastrophysics: The New Science of Eating (2017), he writes: “Many of the food properties that we find highly desirable – crispy, crackly, carbonated, creamy – depend, at least in part, on what we hear.”

Spence’s breakthrough experiment “Sonic Chip”, which won the Ig Nobel prize for improbable research in 2008, further cemented the relationship between taste and sound. By changing the volume of the crunch, he was able to alter people’s perception about how good a potato chip tasted, when in fact, they were all given identical Pringles potato chips.

Through generations of conditioning, our brains associate crunchy and crispy sounds with freshness. This is why fast food advertisements nowadays often place so much emphasis on the ASMR aspect. If you turn off the volume, there is no way to distinguish whether that particular piece of fried chicken tastes good. The signature crunch acts as a condiment to improve your overall fast food experience!

So, what makes “The Crunch” so irresistible? Spence believes that there may be several reasons: “The noise draws attention to the mouth in the way something silent cannot. If you’re eating paté, your attention can drift elsewhere. But a crunch will draw your attention to what you’re eating, making you concentrate on it, even if you can’t see what you’re putting into your mouth.” That’s why cinema popcorn never tastes the same when you’re eating it outside of the movie theatre.

John S. Allen, a research scientist at the University of Southern California, says that the answer stems from our ancestors’ eating habits. “Sometime between one to two million years ago, our ancestors started to make and use fire to cook food. This opened up a whole new world of energy-rich foods to eat. Cooking introduced a source of crispy foods while giving them the nutrition they needed.”

Because they loved the crunch factor so much, our ancestors started looking for other sources of crispy food. Combine that with evolution, and here we are today. Crunchy, fried food is usually high in fat content, and our brains are wired to prefer fat that provides energy to the body. After all, the human brain is made up of at least 60% fat!

The next time you find yourself craving fried chicken or potato chips, remember: it’s not your fault. You’re just genetically built to gravitate towards “The Crunch”!

Liked the article above? You might enjoy reading these too:
How Sound Engineering Is Changing Consumer Experience
Progressive Dining Experiences That Marry Taste & Sound
What Is ASMR And Why Is It So Popular?

This article was originally published in Chinese on Sound of Life on 26 February 2021.

Cover Credit: SOL Team

Writer | Michelle Tan

Lover of all things bizarre, Michelle has a soft spot for dinosaurs, animal videos and a strong G&T. Her lifelong dream is to become an urban hermit.