Research Investigating the Relationship between Shape and Taste of Chocolate Pieces Printed by a 3D Food Printer Accepted by Frontiers in Psychology
This is Shigeo YOSHIDA, a Senior Researcher at OMRON SINIC X (OSX).
We are glad to announce that our paper demonstrating that the shape of chocolate pieces printed by a 3D food printer could change how we perceive taste has been accepted for publication in Frontiers in Psychology.
This research was done with Kazuhiro Ogata (an intern from Kyoto Institute of Technology) and Reo Gakumi (an intern from Kyoto University).
Kazuhiro Ogata, Reo Gakumi, Atsushi Hashimoto, Yoshitaka Ushiku, and Shigeo Yoshida. 2023. The Influence of Bouba- and Kiki-like Shape on Perceived Taste of Chocolate Pieces. Frontiers in Psychology, Vol.14, June 2023. https://doi.org/10.3389/fpsyg.2023.1170674
This research revealed that the interaction between different modalities (in this case, taste and visual/tactile), which is called “Crossmodal Correspondences,” can be used to change the perceived taste of chocolate pieces made with the same ingredients and quantity. For more information, please refer to our paper.
Crossmodal Correspondences
Humans feel a natural connection between different modalities, such as sight and hearing (e.g., “bright voices” and “dark voices”). This non-arbitrary associative relationship between different modalities is called “Crossmodal Correspondences.”
A well-known example of crossmodal correspondences is the “Bouba-Kiki”. When asked the question, “If you had to name the two shapes below, which would be Bouba and which would be Kiki?” most people will answer that the left one is Kiki and the right one is Bouba.
Bouba-Kiki is not limited to the association between shape and sound. It has also been shown that there are consistent associative relationships among people for shape and smells/tastes.
For example, when asked someone to smell a certain odor and to choose between “Bouba” and “Kiki,” the responses tended to be “Kiki” for sour odors and “Bouba” for sweet odors. Also, when asked someone to choose between “Bouba” and “Kiki” as the word for representing taste, the responses tended to be “Kiki” for sour tastes and “Bouba” for sweet tastes.
On the other hand, there is little research that has investigated the taste perceived when actually eating a food with a certain shape (e.g., Bouba and Kiki) (*1), rather than the shape recalled from the taste or the taste recalled from the shape.
In this research, we conducted an experiment to investigate the relationship between the shape of a chocolate piece and the taste perceived when eating it, using “chocolate,” a familiar food that contains a variety of tastes such as bitter, sweet, and sour.
*1 Just as we were preparing for the experiments for this research, a study was published in which they also evaluated the taste perception by eating Bouba-Kiki shaped gelatin (relatively neutral taste/flavor).
Printing Chocolate in Bouba- and Kiki-like Shape using a 3D Food Printer
It was necessary to produce a large number of chocolate pieces of different shapes for the participants to eat to conduct this experiment.
Therefore, we decided to use a “3D food printer” for this research. A 3D food printer is a kind of 3D printer that can handle food as a printing material and can print food of any shape and structure by extruding paste-like food through a thin nozzle and building it up in layers. Referring to past research on Bouba-Kiki, we used a 3D food printer to print chocolate pieces of four different shapes.
3D models similar to the ones we printed are available on github.
Experiment
Participants in the experiment were asked to taste four different chocolate pieces in sequence and to fill out a questionnaire about the taste of these pieces (n=24).
Bayesian analysis of the experimental result revealed that the Bouba-shaped chocolate pieces tasted sweeter than the Kiki-shaped pieces (p(Bouba-A6 > Kiki-A6) = 98.7%, p([Bouba-A6, Bouba-S6] > [Kiki-A6, Kiki-A10]) = 90 .0%). However, no differences were found in the ratings for sourness and bitterness.
Conclusion
Our study shows that the shape of the food we consume affects our taste perception and that 3D food printers have the potential to design new taste experiences.
In addition to this research, OSX is researching and developing systems that leverage the perceptual and cognitive properties of humans (e.g., a musical instrument practice support system that utilizes timbre-shape correspondences) and is designing a future where people and machines are in harmony based on an understanding of people.
Call for Interns
At OSX, we will continue fundamental research on natural language processing, computer vision, machine learning, robotics, and human-computer interaction (HCI). If you are interested in working with us as an intern, please visit our call for internship page.
