Introduction
Eating or drinking of foods associates with multiple interconnected sensory aspects. During consumption, the sensory perception of an individual is influenced by intrinsic factors like the ingredients in the food, nature of food, colour, taste and flavour, in addition to extrinsic factors. The latter includes the environment of dining and even the accompanying person. For example, when we eat potato chips, it is a tendency that we first see the fried chips and then the spices coating the chips. During biting, the human brain senses the aroma of fried potato; this is followed by perception of chewiness and crispness during each bite. In the end comes the taste – an appealing, mildly spicy, or sweet sensation that triggers the second and third bites. Most often, the interest given to taste and flavour is way above the focus on sound.
However, over the decades, scientists have proven that auditory hints we listen while eating play an important role in taste perception (Arroyo, C et al., 2021). For example, while drinking a hot cup of cappuccino, the glug-glug sound of coffee as it is poured into the mug, or the crackle sound while eating salted potato chips give satisfying eating experiences. Our sense of taste begins when the food is in contact with the taste buds which are integrated into fleshy bumps on our tongue, nose and throat. Smell sensation originates initially in the receptor linings of our nostrils and travels along the retro-nasal passages into the mouth and back of the throat. While most often only five taste senses (sweet, sour, salty, bitter and umami) are considered during eating, over 150 years ago, French perfumerist G.W. Piesse hypothesized that there could be a connection between our senses of hearing and smell. He even tried to design a catalogue which could act like a framework or strategy to connect smells based on auditory pitches. Although, a direct connection between smell and taste could not be proven at that time, after few decades, in 2003, Charles Spence, a professor of experimental psychology at Oxford University, attempted to demonstrate the link between food and sound. His works provide insightful contributions in understanding sonic seasoning and resulting sensory aspects.
Sonic Seasoning
Extrinsic factors have been an interest of study among scientists because of interesting findings involving the effect of music played, the container/ vessel type the food is served and even the nature of the material with which the vessel is designed/manufactured. This way, the effect of noise/sound that is intentionally introduced while eating is known to impact the sensory characteristics of food eaten. This sonic seasoning involves deliberate inclusion of music or soundscapes to influence overall sensory experiences. In an experiment conducted by Professor Charles, each subject was allowed to enter a soundproof booth setup, sit in front of a microphone and wear headphones. The setup was configured in such a way that it allowed altering the frequency and volume of sounds that the subjects heard when they were eating a piece of Pringles potato. Interestingly, participants evaluated the chips to be 15% more fresh when they heard a high-pitch crunch while eating than softer chips, although all the given chips were identical (Zampini, M et al., 2004).
When sound is added to an eating experience, it may change the levels of sweetness, bitterness, or sourness perceived from food taste. In general, high-pitched sounds make the food to taste sweet and sour, while lower-pitched and dissonant sounds make it taste bitter. Similarly, staccato sounds make the food crunchy and smooth, whereas legato sounds make the food taste creamy. In general, crispy foods produce high-frequency sounds when we bite them, whereas crunchy foods make sounds at a low-frequency range, giving new perspectives about the relationships between sound and texture (Demattè, M. L., et al., 2021). Incorporating mastication sounds can influence the overall acceptability and texture perception of food materials. In fact, more than ever, recent empirical studies suggest that playing music can bias our food and drink choices or even change our perception of the food.
As a practical application, sonic seasoning was brought to real-time by British Airlines for long-flight passengers. Working along with Professor Charles and team from Oxford University, the airlines team designed a special track playlist according to foods served to elevate dining experience for passengers. Quoting that the tasting ability would reduce by 30% when we fly, the team believes that the sonic seasoning would help bring out food flavours.
Effect of background music
Background music has been shown to dramatically affect the sensory perception of the food. For example, when people listen to a high-frequency soundtrack, they may rate a chocolate as sweet, but as bitter while listening to low-frequency soundtrack. Such examples emphasize the strong impact of background music on people’s food choices. As in Figure 1, a coffee shop in Korea allows customers to choose music and coffee blends from the given choices in an iPad. Later, coffee is served along with a headphone playing the selected music. Overall, this has been received well by the customers. In general, listening to classical music is known to bring joy and serenity, associated with its quality and sophistication. Utilizing this fact, increasingly higher number of restaurants and supermarkets are making their customers spend more time in their places. Specifically, the emotional factor of music that a person listens can be scientifically connected with multisensory tasting experiences. More specifically, rhythm can influence our food particularly by matching eating speed. That is, faster music can trigger us to eat more quickly, while slower music can make us eat longer than usual (Milliman, R. E. et al., 1986). Overall, music can change taste and texture perception. From a different perspective, food sounds can facilitate the judging of its freshness and quality. In a recent study, a group of scientists found that the same ice-cream tasted more sweet and evoked positive emotions while listening to forest/bird soundscapes, but tasted bitter and evoked negative emotions in machine-soundscapes (Xu Y et al., 2019).
Sound plays a vital role in daily interactions between customers and products, often impacting their cognitive processes and emotions. Now more than ever, companies are becoming actively interested in the acoustic design of their products. The Oxford University professor revealed exactly why packages make so much noise when we wrinkle them and why chips themselves are so crunchy. In another experiment conducted by Professor Spence, it was observed that a noisy package and a very crispy crunch makes the snack more tasteful. Crumbling sounds enable a delicious and fresher perception to foods. Even the sound of food packaging can alter the perception of food quality. When Lerma, et al. (2017) studied how packaging sound would influence taste perception, some interesting observations were made. It was found that the sound produced by the same spoon against different containers such as glass, clay and polypropylene influenced the overall taste perception. These kinds of results have increased the curiosity of many scientists to work in this area.
Multi/mode sensory preferences or cross modal influence
What exactly happens to our brain when we listen to music while eating? Dr. Qian Janice Wang, who studied the association of hearing stimuli with flavours, explained that three major theories could be conceptualized to understand this question. The first theory explains about the evolution of human eating psychology to predict foods before eating them. Accordingly, sounds while eating can also influence our predictions about foods (Wang, Q. J.et al., 2020). According to the second theory, a concept of attention capture is told; when foods have complex flavours, specific sounds would make us more attentive to some taste or flavour over others. For example, a low-pitched sound can make a food taste more bitter (Wang, Q. J., et al., 2017). Finally, the third theory explains that sounds and music can arouse certain emotions within us, which can carry over into how we feel about a food and this is explained as ‘emotion mediation’ or ‘the halo effect’ (Kantono, K. et al 2016). These innovative concepts have also been welcomed by many restaurants and food researchers. In the UK, Fat Duck (restaurant) offers a dish called the Sound of the Sea – this is served along with an iPod playing sounds of the seaside. These sounds reportedly make the food taste fresher among customers.
As reported by scientists, there is a great scope to utilize sounds to enhance food perception especially within hospitals, restaurants or elderly homes. In addition, music would also leave a significant impact in triggering nostalgia, especially in case of older patients who might be suffering from memory loss and this factor could bring more satisfaction and happiness during eating. As a conclusion, this method has greater potential and scope to take food perception beyond imagination and can lead to a healthier diet. Besides, sonic seasoning is expected to have a great scope in revolutionizing the culinary industry.
If you are finding music being played in a restaurant, then please keep an eye on the bill! Yes, because scientists explain that background sounds have the power to influence your bill. All along, sound has been the silent/ secret/ unusual ingredient in our food that has been influencing our perception. Sonic seasoning is the deliberate introduction of music/sound so as to help in altering the perception towards flavour/ taste of the food. Even though the same coffee was given to the people during an evaluation on the type of influencing ad, vertically displayed contents impacted sweeter tastes as compared to horizontal ads. While this sounds weird, such unique results are pushing scientists to investigate more of cross-model influences on sensory applications.
Future scope and challenges
Overall, sonic seasoning has the capability to influence or trigger a cross-modal effect in the tasting experience of foods. The use of sonic seasoning could result in either a positive nutritious/healthy eating or in playful eating. Although, few researchers also consider that intrusion of technology in the dining space is unnecessary, some believe that it could improve the overall eating experience. But the concept of considering the influence of sound on sensory perception has been recognized by scientists as an area of growing potential.
This technology can be used effectively in hospitals or in places where the environment may otherwise be discouraging. On a positive note, sonic seasoning of food has received an appreciation that it can significantly help patients. In the field of integrative medicine which involves complementing and alternatives to existing medicine, music can be an effective tool to emotionally support psychologically affected patients. This technology while bringing to practicality still requires a lot of regulations to prevent exploitation and forging of customers, as their choices could be forced externally. This is because their usage by restaurants and hotels could be exploiting the human psychology.
The major challenge involved as referred by researchers is that it is completely a relative observation. Aspects are prone to change according to persons, natures and emotions, associating heavily with external conditions. The testing of same person on a different day might be different. Hence, the degree of change in perception cannot be assured or quantified as it varies person to person under same experimental conditions. Scientists recommend that conducting long term studies on large group of people could help to understand the individual differences which would bridge the gap on such relative perceptions. Analyzing with fuzzy logic and artificial neural networks or demonstrating with empirical relations would help in increasing the acceptability and reliability of such techniques. This can further provide key opportunities to implement the technology in real-time applications to design multi-sensory food experiences.
References
• Arroyo, C., & Arboleda, A. M. (2021). Sonic food words influence the experience of beverage healthfulness. Food Quality and Preference, 88, 104089
• Zampini, M., & Spence, C. (2004). The role of auditory cues in modulating the perceived crispness and staleness of potato chips. Journal of sensory studies, 19(5), 347-363.
• Milliman, R. E. (1986). The influence of background music on the behavior of restaurant patrons. Journal of consumer research, 13(2), 286-289
• Demattè, M. L., Pojer, N., Endrizzi, I., Corollaro, M. L., Betta, E., Aprea, E., … & Gasperi, F. (2014). Effects of the sound of the bite on apple perceived crispness and hardness. Food Quality and Preference, 38, 58-64.
• Lerma, Beatrice; Dal Palù, Doriana; Buiatti, Eleonora., 2017, The taste of the sound or the sound of the taste? How sounding packaging influence food perception, Online School of Food Design, 2017. PORTO@IRIS, http://onlineschooloffooddesign.org/p/food-design-conference.
• Wang, Q. J., Spence, C., & Knoeferle, K. (2020). Timing is everything: Onset timing moderates the crossmodal influence of background sound on taste perception. Journal of Experimental Psychology: Human Perception and Performance.
• Wang, Q. J., Mesz, B., & Spence, C. (2017, November). Assessing the impact of music on basic taste perception using time intensity analysis. In Proceedings of the 2nd ACM SIGCHI International Workshop on Multisensory Approaches to Human-Food Interaction (pp. 18-22)
• Kantono, K., Hamid, N., Shepherd, D., Yoo, M. J., Grazioli, G., & Carr, B. T. (2016). Listening to music can influence hedonic and sensory perceptions of gelati. Appetite, 100, 244-255.
• Xu, Y., Hamid, N., Shepherd, D., Kantono, K., Reay, S., Martinez, G., Spence C. (2019). Background soundscapes influence the perception of ice-cream as indexed by electrophysiological measures. Food Research International, 125, 108564
• Spence, C. (2020). Multisensory flavour perception: Blending, mixing, fusion, and pairing within and between the senses. Foods, 9(4), 407.
About the Authors:
1M. Kavimughil, 2S. Kavin Prasanth, 3J.A. Moses & 4C. Anandharamakrishnan*
Computational Modeling and Nanoscale Processing Unit
National Institute of Food Technology, Entrepreneurship and Management – Thanjavur
Ministry of Food Processing Industries, Government of India
Thanjavur, Tamil Nadu – 613005, India.
Corresponding Author Email ID: *anandharamakrishnan@iifpt.edu.in
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