Psychological Process
Research Team
Research Summary
We conduct research to elucidate the computational mechanisms of human mind (emotions, cognition, and behavior) to develop robots with mind.
- Main Research Fields
-
- Experimental psychology
- Basic/Social brain science
- Intelligent robotics
- Keywords
-
- Emotion
- Facial expression
- Social interaction
- Human-robot interaction
- Neuroimaging
- Research theme
-
- Computational elucidation of human mind; its implementation in robots collaborating with engineers.
- Psychological evaluation of robots' functions.
- Interdisciplinary research across psychology, informatics, and robotics, especially on emotional communication.
Wataru Sato

History
- 2005
- Primate Research Institute, Kyoto University
- 2010
- Hakubi Center, Kyoto University
- 2014
- Graduate School of Medicine, Kyoto University
- 2017
- Kokoro Research Center, Kyoto University
- 2020
- RIKEN
Award
- 2011
- Award for Distinguished Early and Middle Career Contributions, The Japanese Psychological Association
Members
- Chun-Ting Hsu
- Research Scientist
- Akie Saito
- Research Scientist
- Koh Shimokawa
- Technical Staff I
- Masaru Usami
- Research Part-time Worker II
- Yang Dongsheng
- Student Trainee
- Naoya Kawamura
- Student Trainee
Former member
- Shushi Namba
- Research Scientist(2020/10-2023/03)
- Saori Namba
- Research Part-time Worker I(2021/04-2023/03)
- Rena Kato
- Research Part-time Worker II (2020/07-2022/01)
Research results
Emotional valence sensing using a wearable facial EMG device
(Sato, Murata, Uraoka, Shibata, Yoshikawa, & Furuta: Sci Rep)
Emotion sensing using physiological signals in real-life situations can be practically valuable. Previous studies developed wearable devices that record autonomic nervous system activity, which reflects emotional arousal. However, no study has determined whether emotional valence can be assessed using wearable devices.
To this end, we developed a wearable device to record facial electromyography (EMG) from the corrugator supercilii (CS) and zygomatic major (ZM) muscles.
To validate the device, in Experiment 1, we used a traditional wired device and our wearable device, to record participants' facial EMG while they were viewing emotional films.
Participants viewed the films again and continuously rated their recalled subjective valence during the first viewing. The facial EMG signals recorded using both wired and wearable devices showed that CS and ZM activities were, respectively, negatively and positively correlated with continuous valence ratings.
In Experiment 2, we used the wearable device to record participants' facial EMG while they were playing Wii Bowling games and assessed their cued-recall continuous valence ratings. CS and ZM activities were correlated negatively and positively, respectively, with continuous valence ratings.
These data suggest the possibility that facial EMG signals recorded by a wearable device can be used to assess subjective emotional valence in future naturalistic studies.

Enhanced emotional and motor responses to live vs. videotaped dynamic facial
(Hsu, Sato, & Yoshikawa: Sci Rep)
Facial expression is an integral aspect of non-verbal communication of affective information. Earlier psychological studies have reported that the presentation of prerecorded photographs or videos of emotional facial expressions automatically elicits divergent responses, such as emotions and facial mimicry.
However, such highly controlled experimental procedures may lack the vividness of reallife social interactions.
This study incorporated a live image relay system that delivered models’ real-time performance of positive (smiling) and negative (frowning) dynamic facial expressions or their prerecorded videos to participants. We measured subjective ratings of valence and arousal and facial electromyography (EMG) activity in the zygomaticus major and corrugator supercilii muscles.
Subjective ratings showed that the live facial expressions were rated to elicit higher valence and more arousing than the corresponding videos for positive emotion conditions. Facial EMG data showed that compared with the video, live facial expressions more effectively elicited facial muscular activity congruent with the models’ positive facial expressions.
The findings indicate that emotional facial expressions in live social interactions are more evocative of emotional reactions and facial mimicry than earlier experimental data have suggested.

Selected Publications
- Hsu, C.-T., Sato, W., Kochiyama, T., Nakai, R., Asano, K., Abe, N., & Yoshikawa, S. (in press). Enhanced mirror neuron network activity and effective connectivity during live interaction among female subjects.Neuroimage.
- Sato, W., & Kochiyama, T. (2022). Exploration of emotion dynamics sensing using trapezius EMG and fingertip temperature. Sensors, 22, 6553.
- Sawada, R., Sato, W., Nakashima, R., & Kumada, T. (2022). How are emotional facial expressions detected rapidly and accurately? A diffusion model analysis. Cognition, 229, 105235.
- Namba, S., Sato, W., Nakamura, K., & Watanabe, K. (2022). Computational process of sharing emotion: An authentic information perspective. Frontiers in Psychology, 13, 849499.
- Sawabe, T., Honda, S., Sato, W., Ishikura, T., Kanbara, M., Yoshikawa, S., Fujimoto, Y., & Kato, H. (2022). Robot touch with speech boosts positive emotions. Scientific Reports, 12, 6884.
- Namba, S., Sato, W., & Matsui, H. (in press). Spatio-temporal properties of amused, embarrassed and pained smiles. Journal of Nonverbal Behavior.
- Saito, A., Sato, W., & Yoshikawa, S.(2022). Rapid detection of neutral faces associated with emotional value among older adults. Journal of Gerontology: Psychological Sciences, 77, 1219-1228.
- Sato, W., Namba, S., Yang, D., Nishida, S., Ishi, C., & Minato, T.(2022). An android for emotional interaction: Spatiotemporal validation of its facial expressions. Frontiers in Psychology, 12, 800657.
- Uono, S., Sato, W., Kochiyama, T., Yoshimura, S., Sawada, R., Kubota, Y., Sakihama, M., & Toichi, M.(2022). The structural neural correlates of atypical facial expression recognition in autism spectrum disorder. Brain Imaging and Behavior, 16, 1428-1440.
- Saito, A., Sato, W., & Yoshikawa, S.(2022). Rapid detection of neutral faces associated with emotional value. Cognition and Emotion, 36, 546-559.
- Sato, W., Ikegami, A., Ishihara, S., Nakauma, M., Funami, T., Yoshikawa, S., & Fushiki, T.(2021). Brow and masticatory muscle activity senses subjective hedonic experiences during food consumption. Nutrients, 13, 4216.
- Namba, S., Sato, W., & Yoshikawa, S.(2021). Viewpoint robustness of automated facial action unit detection systems. Applied Sciences, 11, 11171.
- Sato, W.(2021). Color's indispensable role in the rapid detection of food. Frontiers in Psychology, 12, 753654.
- Uono, S., Sato, W., Sawada, R., Kawakami, S., Yoshimura, S., & Toichi, M.(2021). Schizotypy is associated with difficulties detecting emotional facial expressions. Royal Society Open Science, 8, 211322.
- Sato, W., Usui, N., Sawada, R., Kondo, A., Toichi, M., & Inoue, Y. (2021). Impairment of emotional expression detection after unilateral medial temporal structure resection. Scientific Reports, 11, 20617.
- Huggins, C., Cameron, I.M., Scott, N.W., Williams, J.H., Yoshikawa, S., & Sato, W. (2021). Cross-cultural differences and psychometric properties of the Japanese Actions and Feelings Questionnaire (J-AFQ). Frontiers in Psychology, 12, 722108.
- Namba, S., Sato, W., Osumi, M., & Shimokawa, K. (2021). Assessing automated facial action unit detection systems for analyzing cross-domain facial expression databases. Sensors, 21, 4222.
- Zickfeld, J.H., van de Ven, N., Pich, O., Schubert, T.W., Berkessel, J.B., Pizarro, J.J., Bhushan, B., Mateo, N.J., Barbosa, S., Sharman, L., K ökönyei, G., Schrover, E., Kardum, I., Aruta, J.J.B., Lazarevic, L.B., Escobar, M.J., Stadel, M., Arriaga, P., Dodaj, A., Shankland, R., Majeed, N.M., Li, Y., Lekkou, E., Hartanto, A., Özdoğru, A.A., Vaughn, L.A., Espinozay, M.C., Caballero, A., Kolen, A., Karsten, J., Manley, H., Maeura, N., Eşkisu, M., Shani, Y., Chittham, P., Ferreira, D., Bavolar, J., Konova, I., Sato, W., Morvinski, C., Carrera, P., Villar, S., Ibanez, A., Hareli, S., Garcia, A.M., Kremer, I., Götz, F.M., Schwerdtfeger, A., Estrada-Mejia, C., Nakayama, M., Ng, W.Q., Sesar, K., Orjiakor, C., Dumont, K., Allred, T.B., Gračanin, A., Rentfrow, P.J., Sch önefeld, V., Vally, Z., Barzykowski, K., Peltola, H.R., Tcherkassof, A., Haque, S., Śmieja, M., Su-May, T.T., IJzerman, H., Vatakis, A., Ong, C.W., Choi, E., Schorch, S.L., Páez, D., Malik, S., Kačmár, P., Bobowik, M., Jose, P., Vuoskoski, J., Basabe, N., Doğan, U., Ebert, T., Uchida, Y., Zheng, M.X., Mefoh, P., Šebeňa, R., Stanke, F.A., Ballada, C.J., Blaut, A., Wu, Y., Daniels, J.K., Kocsel, N., Burak, E.G.D., Balt, N.F., Vanman, E., Stewart, S.L.K., Verschuere, B., Sikka, P., Boudesseul, J., Martins, D., Nussinson, R., Ito, K., Mentser, S., Çolak, T.S., Martinez-Zelaya, C., & Vingerhoets, A. (2021). Tears evoke the intention to offer social support: A systematic investigation of the interpersonal effects of emotional crying across 41 countries. Journal of Experiment Social Psychology, 95, 104137.
- Nishimura, S., Nakamura, T., Sato, W., Kanbara, M., Fujimoto, Y., Kato, H., & Hagita, N. (2021). Vocal synchrony of robots boosts positive affective empathy. Applied Sciences, 11, 2502.
- Sato, W., Murata, K., Uraoka, Y., Shibata, K., Yoshikawa, S., & Furuta, M. (2021). Emotional valence sensing using a wearable facial EMG device. Scientific Reports, 11, 5757.
- Sato, W., Yoshikawa, S., & Fushiki, T. (2021). Facial EMG activity is associated with hedonic experiences but not nutritional values while viewing food images. Nutrients, 13, 11.
- Nishimura, S., Kimata, D., Sato, W., Kanbara, M., Fujimoto, Y., Kato, H., & Hagita, N. (2020). Positive emotion amplification by representing excitement scene with TV chat agents. Sensors, 20, 7330.
- Sato, W., Kochiyama, T., & Yoshikawa, S. (2020). Physiological correlates of subjective emotional valence and arousal dynamics while viewing films. Biological Psychology, 157, 107974.
- Sato, W., Rymarczyk, K., Minemoto, K., & Hyniewska, S. (2020). Cultural differences in food detection. Scientific Reports, 10, 17285.
- Hsu, C.-T., Sato, W., & Yoshikawa, S.(2020). Enhanced emotional and motor responses to live vs.videotaped dynamic facial expressions. Scientific Reports, 10, 16825.
- Sato, W., Uono, S., & Kochiyama, T. (2020). Neurocognitive mechanisms underlying social atypicalities in autism: Weak amygdala’s emotional modulation hypothesis. Frontiers in Psychiatry, 11, 864.
- Sato, W. (2020). Association between dieting failure and unconscious hedonic responses to food. Frontiers in Psychology, 11, 2089.
- Sato, W., Minemoto, K., Sawada, R., Miyazaki, Y., & Fushiki, T. (2020). Image database of Japanese food samples with nutrition information. PeerJ, 8, e9206.
- Sato, W., Minemoto, K., Ikegami, A., Nakauma, M., Funami, T., & Fushiki, T. (2020). Facial EMG correlates of subjective hedonic responses during food consumption. Nutrients, 12, 1174.
- Saito, A., Sato, W., & Yoshikawa, S. (2020). Older adults detect happy facial expressions less rapidly. Royal Society Open Science, 7, 191715.
- Williams, J., Huggins, C., Zupan, B., Willis, M., Van Rheenen, T., Sato, W., Palermo, R., Ortner, C., Krippl, M., Kret, M., Dickson, J., Li, C S R., & Lowe, L. (2020). A sensorimotor control framework for understanding emotional communication and regulation. Neuroscience and Biobehavioral Reviews, 112, 503-518.
- Sato, W.*, Kochiyama, T.*, Uono, S., Sawada, R., & Yoshikawa, S.(* equal contributors) (2020). Amygdala activity related to perceived social support. Scientific Reports, 10, 2951.
- Kong, F., Heller, A.S., van Reekum, C.M., & Sato, W. (2020). Editorial: Positive neuroscience: the neuroscience of human flourishing. Frontiers in Human Neuroscience, 14, 47: 1-3.
Links
Psychological Process Research Team(RIKEN)
Contact Information
wataru.sato.ya [at] riken.jp