Visualizing taste” by expressing the impression one gets from taste in an abstract form

At “Brain World 2024 for Everyone: Super Diversity,” visitors can come into contact with cutting-edge research results from various companies, universities, and research institutes that are working to realize a neurodiverse society. The Multisensory and Cognitive Design Laboratory at Ritsumeikan University is engaged in research to visualize the impressions that each person receives from different tastes by expressing them in abstract form. Nanako Ishido (Photo 5), director of the B Lab, which is promoting the “Brain World for Everyone” exhibition, interviewed Professor Arifumi Wada (Photo 1) of the laboratory.

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Professor, Multisensory and Cognitive Design Laboratory, Ritsumeikan University
Mr. Yushi Wada

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If the impression we get from the taste of food is the same as the impression we get from its shape
I think we can express the taste in a visual form.

Ishido: “This is the second time for the Multisensory and Cognitive Design Laboratory of Ritsumeikan University to participate in the exhibition, following the 2023 event. Could you describe your latest research, including the contents of your exhibit at “Brain World for Everyone”?”

Wada: “At Ritsumeikan University’s Multisensory and Cognitive Design Laboratory, we are engaged in research focusing on ‘eating and tasting,’ including how we experience food with our five senses. We will be exhibiting our work on the theme of “Sweet and Bitter Forms – Visualization of Flavor. How do you taste food? When I ask this question, many people say, “I taste with my tongue inside my mouth. In the past, it was believed that different tastes were perceived more strongly on different parts of the tongue, such as bitterness on the back of the tongue, and even elementary school supplementary readers drew a “taste chart of the tongue”. However, it was well known to taste researchers that this was not the case. Research has now advanced, and it is now known that taste buds exist on the tip, sides, and back of the tongue, and that each taste bud has receptors (like sensors) that sense sour, salty, sweet, umami, bitter, and other tastes. (▲Picture 2▲)

This means that people taste with their entire tongue, but in fact, it is not only the tongue that tastes, but sight is also deeply involved in taste. For example, shaved ice syrup tastes almost the same as strawberry, melon, etc., even though the smell and color of the fruits are different.

With this in mind, we are conducting a slightly different kind of research. From the perspective that vision is related to the taste of food, we are asking people about their impressions of the taste and shape when they taste a certain food, and we are investigating whether visual forms that are consistent with the impression of sweetness in the mouth of a certain food may appear to express sweetness. To a variety of people, chocolate flavors can include sweet, milky, melty, and bitter. Using the semantic differential method, a psychological technique, we asked not only about impressions of these flavors, but also about impressions of various forms, to see if any of the flavors and forms produced similar impressions. (Photo 3)

Then, we have found that the shape that produces an impression similar to that of “sweet,” “milky,” “melting,” and “bitter” tastes is this shape. In fact, many people feel this way, and if this is the case, they may be tasting not only with their tongue and nose, but also with their eyesight and other five senses combined.

Chocolate gives a strong impression of sweetness, but we would like visitors to actually try the same chocolate and think about ‘what would happen if it were no longer sweet? In the “Everyone’s Brain World” exhibit, we would like visitors to try the “no longer sweet chocolate” and experience how the impression of sweetness would change into a form that expresses the impression of bitterness.

In this demonstration, we will use the fact that when people drink Gymnema tea, which is sold as a diet tea, the Gymnemic acid attaches to their sweet receptors, and for a while, they do not feel sweetness anymore, The participants were asked to experience how their impression of the chocolate changed before and after drinking the Gymnema tea. (Photo 4)

Which do you feel is sweeter and which do you feel is bitter? 90% of you feel that the left side is sweeter, but do you feel the same way? We are also investigating and researching whether people feel that the same chocolate is bitter when only the sweetness is gone, even if there is the smell of chocolate.

In some cases, when patissiers are asked to look at this kind of research, they will say, “You know, I feel like that, don’t you? In fact, a famous patissier once made a sweet shaped chocolate and a bitter shaped chocolate.

I believe that we actually enjoy food with our eyes, so I feel that ‘food is something to be tasted with all five senses. There is also diversity in the sense of taste, with some people feeling extremely bitter about certain foods, and others not feeling the opposite. If we do not understand this and force people to eat a food because they do not find it bitter, it may be extremely bitter to the person or child who finds it bitter. So, we need to know how the five senses work so that we can enjoy the gap in communication and have a happy eating life without forcing people to eat foods that they don’t like. I think we need to know how the five senses work.

Considering Diversity in Taste

Ishido: “I also experienced Dr. Wada’s research last year and was surprised at how much the impression of chocolate changes just by losing its sweetness. So I would like to ask you, why do so many people associate sweet foods with ’rounded shapes’?”

Wada: “The Buba/Kiki effect is well-known for voice impressions of shape, and roundness is almost always a positive impression. Internationally, there is agreement that sweet is a round impression. There is no definitive reason for this, but it seems certain that sweet has a round impression worldwide.

Ishido: “It is my own impression, but I thought that ‘bitter’ food is something that should not be eaten in some cases, and that humans need to sense danger in order to protect their lives, and that is why it has a ‘thorny impression’. On the other hand, I also thought that sweetness is a positive thing for human life, which is why we have the impression of roundness and warmth.

Mr. Wada: “I think there is. There are few variations of receptors for sweet and umami tastes, but there are 25 different types of receptors for bitter tastes. It is often said that we are trying to detect what is not good for the body by making full use of these varied receptors. Bitterness is something that we have to defend against, so I think it is a function of ‘dislike’ in the first place.

Taste and form have been studied in many different places. However, most researchers directly try to understand the connection between taste and shape by combining them, but I am doing research in which I ask for several levels of impressions such as ‘good/bad’ and ‘active/inactive’ between taste and shape and connect them with these impressions as well. This is called the semantic differential method, and it is a study to connect these impressions with ‘hazy’ impressions that are not specific to each sense, as can be measured by this technique.

Ishido: “I was also shocked when I first heard that all shaved ice syrups taste the same and are only different colors, but the human brain can be fooled to that extent. I wondered if people would feel “bitterness” if the color of something very sweet was toxic.

Mr. Wada: “As for shaved ice syrups, there are differences in smell. For example, when you lick a candy, if you pinch your nose and lick it, you may not be able to tell what flavor of candy it is. It is not as if a poisonous color makes something sweet bitter. It is difficult to induce bias in the intensity of a sense when what each sense indicates is not quite consistent. It may feel like an emphasis when the meanings match, or a sweet food with a toxic color may feel awesomely intense and sweet. I think it is only when these directions are combined that an impression with a change in intensity occurs. We cannot change the taste in the exact opposite direction, but I believe we can emphasize when the impressions coincide.”

Ishido: “In the “Brain World for Everyone” exhibit, we also have a section where visitors can experience the diversity of the five senses. I contacted Dr. Wada because, although there are researchers on the diversity of sight and hearing, it has been difficult to find a study that shares the differences in taste and smell among the five senses.

Although our neurodiversity project targets all people and is based on the premise that each person is different, there are many people with developmental disabilities and autism spectrum disorders who experience difficulties in their lives due to sensory idiosyncrasies such as visual and auditory sensitivities. What is the range of diversity in terms of taste?

Wada: “In terms of taste, we are often confronted with elderly people who say that they cannot taste anything when they have dry mouth. This makes it difficult for them to swallow, which makes eating less enjoyable. When elderly people become frail and lose their sense of taste, it can be boring to go out, so I think there is one diversity issue to consider.

There are also other cultural differences. Many Koreans like spicy food, but they do not seem to have liked spicy food since they were babies. When I ask Koreans, ‘How did you eat kimchi when you were little?’ they reply, ‘When my parents shared it with me, they washed kimchi with water and fed it to me. They gradually step up to stronger and spicier spiciness, so there is a culture of getting used to spiciness in this way.

Ishido: “Then, the differences in innate taste sensors are not that great?

Mr. Wada: “Although all human beings share the same sense of bitterness, there are 25 variations of bitterness, and it is said that the ratio of some bitternesses perceived as weak or strong varies depending on race. Even within the same race, there is a mix of people who perceive certain “bitterness” extremely strongly and people who do not perceive certain “bitterness” at all. For example, there may be people who eat the same bitter melon stir-fry and say it is not bitter at all.

There can be differences even between parents and children, so when a child says, “I can’t eat this because it is bitter,” you may be giving them a hard time if you force them to eat it by saying, “Don’t tell me what you like and don’t like. In Japan, there is a tendency to force children to eat whatever they want out of concern for food loss, but forcing children to eat foods they don’t like can cause them unimaginable suffering.

Ishido: “You are saying that there are some people who cannot eat certain foods due to inborn differences in taste, such as inability to eat or a strong sense of “bitterness”. By the way, you say that each race has a different sense of taste, but are there any “bitterness” that Japanese people don’t like?

Mr. Wada: “I have only seen some of the data, but I think that Japanese people do not have any outstanding characteristics compared to other races, and are relatively neutral. One well-known data on individual differences in perception of bitterness is PROP, which is said to have a large individual difference in sensitivity to bitterness, but it means that some people may have difficulty perceiving it, not that all Japanese people have difficulty perceiving that bitterness.

Ishido: “I was reminded once again that food is not only about taste, but also about the five senses, including aroma, appearance, and texture. I also feel that it may be difficult to extract and analyze only the sense of taste among them.”

Wada: “Researchers studying receptors may find it easier to conduct research if the research is completed only with taste, but food development researchers seem to think that they need to think comprehensively. There are basically five tastes in the sense of taste, and a new receptor for ‘fatty taste’ has been discovered. And as we learn more about its receptor mechanism, the mystery is deepening.”

Ishido: “The more you know, the deeper the mystery becomes.”

Mr. Wada: “As the world population further increases in the future, plant-based foods and cultured meats are attracting attention. We need to eat more plant foods, but some people inevitably find animal foods tastier, so attempts are being made to achieve a taste like animal foods with plant foods. Some people think, “What is the animal-like taste?” or “Can’t we get by with the aroma?” which have been difficult to research so far, while some companies are researching that there is a secret in the receptor mechanism and that even plant foods can provide the satisfaction of animal foods if their conditions are changed. I myself am doing research with them. Aroma, of course, is also important for the five senses, but I am working on it because I believe that delving into both aroma, vision, and the reception mechanism is an important attempt to fill the world with a happy diet after switching to plant-based foods.”

Utilizing advanced technology to visualize not only taste, but other senses as well.

Ishido: “I would like to ask you about visualization of taste. It is sometimes difficult to realize in everyday life that ‘the five senses are diverse and everyone feels differently. That is why I think there is value in visualizing it. I think it is an interesting attempt to visualize the sense of taste. In addition to expressing the sense of taste in a form, is there anything else you are trying to tackle in the visualization of taste? I also feel that other senses, like taste, could be visualized using Dr. Wada’s method. Could you tell us about its application?”

Wada: “First of all, the reason why we shaped the sense of taste was because there was a lot of research on color. Color is the one with the greatest cultural differences. Sour color can be expressed as yellow if you think of lemons, but if you are in a region where only limes are squeezed, it will be green.

I believe that adding other modalities, such as color, will make it even more expressive. For example, it is difficult to convey the taste itself online, but if we can visually express the impression of eating, we may be able to communicate with each other even online. I am thinking that if we can express the impression of eating visually, we can communicate our feelings online as well.

Regarding abstract shapes, I think that “if there were generality across cultures, it would be possible to visualize that we feel different things even if we eat the same food,” and “it would be possible to realize a new way of communicating with the mind, such as feeling the same impression even if we eat different foods.

As for whether it can be applied to other senses, we originally intended to do so. For example, it was pointed out that the reason “Zoom drinking” seemed to be popular but never caught on was that the atmosphere was not communicated. It is possible to make it look like you are eating the same food even if you are eating different foods and in different scenes, and even if you eat the same food, there are people who say it tastes good and people who say it tastes bad. I have a dream that if people could communicate with each other, even if it is only through feelings, they could transcend distance and merge.

Ishido: “That is very interesting. For example, if a Japanese person eats natto (fermented soybeans) and an Indian person eats curry, the same shape appears, so although they are eating different foods, you can tell that this food is like natto for the Japanese people.

Mr. Wada: “Yes, that’s right. We want to make it possible for people to communicate with each other even if they are eating different foods. We are expressing ourselves as if we are in tune with the five tastes, but we hope that we can communicate only with our feelings. Happy moods, sad moods, and so on across countries, so I think everyone likes food regardless of country, so maybe all we need to do is just communicate our feelings.”

Ishido: “Perhaps it is an attempt to convert taste into emotion through visualizing the differences in taste.

Mr. Wada: “A communication of feelings that transcends culture. I think it would be interesting to see, ‘Oh, those people are so happy to eat that.

Ishido: “After taste, what would you tackle next?”

Mr. Wada: “It is not food, but I am thinking about the state of my body. There are times when your mind and body are disconnected. If you are invited to go out for a drink, but you don’t want to drink because you don’t feel well, you might lie and say, ‘My family is waiting for me at home tonight,’ but it is better to visualize the fact that ‘my body is telling me I can’t drink,’ or to say, ‘My body is telling me I can’t drink. I think it would be good if we could create a communication in which my feelings and my body are conversing with each other. I would like to visualize my body’s feelings.

Ishido: “That is very interesting. Certainly, if you visualize your physical condition, you can become aware of things such as ‘I am very tired right now,’ and you may be able to be honest about your physical and mental state.

Mr. Wada: “There are mobile devices that can measure vital values, but I think that if you know that ‘my body is sad right now’ and ask yourself, ‘Hey, are you okay? I believe I can have a body that will follow me to my grave.”

Ishido: “What is your message for the realization of a neuro-diverse society and your aspirations for the future of Dr. Wada’s research?

Mr. Wada: “The Japanese have always had interesting thoughts about wellbeing, and there is the concept of ‘the beauty of the unfinished’ by Okakura Tenshin. It means, ‘True beauty is found in those who complete imperfect things in their minds.’ Creating perfection in the mind is one of the virtues of the Japanese people, and I am sure that this will be shared with the world in the future. By remembering such sensitivity, Japanese people may be able to promote attempts such as neurodiversity in the realm of software and create wellbeing in the mind. I believe that if we can reach the borderline of creating perfection where the digital and the mind are combined in the Okakura Tenshin style, we will be able to create a Japanese advantage.”