90 JOURNAL OF COSMETIC SCIENCE CONCLUSION This study investigated the effects of foam with different viscosities used as tactile stimuli, on the emotions of healthy female adults using neurophysiological indices. The tactile stimulation-induced changes in these indices in relation to the foam viscosity indicate that pleasant feelings were evoked by low and medium viscosity foams and more stressful emotions were associated with the high viscosity foam. These results also suggest that neurophysiological indices, such as EEG and salivary cortisol, can be useful for comparing user experiences across different products. ACKNOWLEDGMENTS K.I., M.K., and T.K. are employees of the FANCL Corporation (Yokohama, Kanagawa, Japan). A.G., T.K., T.U., and K.H. declare no potential conflict of interest. This research was funded by the FANCL Corporation. DATA AVAILABILITY The data generated and/or analyzed during the current study are available from the corresponding author on reasonable request. REFERENCES (1) Corniani G, Saal HP. Tactile innervation densities across the whole body. J Neurophysiol. 2020 124(4):1229–1240. (2) Taneja P, Olausson H, Trulsson M, Svensson P, Baad-Hansen L. Defining pleasant touch stimuli: A systematic review and meta-analysis. Psychol Res. 2021 85(1):20–35. (3) Wijaya M, Lau D, Horrocks S, McGlone F, Ling H, Schirmer A. The human “feel” of touch contributes to its perceived pleasantness. J Exp Psychol Hum Percept Perform. 2020 46(2):155–171. (4) Björnsdotter M, Löken L, Olausson H, Vallbo A, Wessberg J. Somatotopic organization of gentle touch processing in the posterior insular cortex. J Neurosci. 2009 29(29):9314–9320. (5) Russo V, Ottaviani C, Spitoni GF. Affective touch: A meta-analysis on sex differences. Neurosci Biobehav Rev. 2020 108:445–452. (6) Basdogan C, Giraud F, Levesque V, Choi S. A review of surface haptics: enabling tactile effects on touch surfaces. IEEE Trans Haptics. 2020 13(3):450–470. (7) Lee Y, Ahn JH7. Biomimetic tactile sensors based on nanomaterials. ACS Nano. 2020 14(2):1220–1226. (8) Yasaka K, Mori T, Yamaguchi M, Kaba H. Representations of microgeometric tactile information during object recognition. Cogn Process. 2019 20(1):19–30. (9) Kida T, Shinohara K9. Gentle touch activates the anterior prefrontal cortex: an NIRS study. Neurosci Res. 2013 76(1-2):76–82. (10) Greco A, Guidi A, Bianchi M, Lanata A, Valenza G, Scilingo EP. Brain dynamics induced by pleasant/unpleasant tactile stimuli conveyed by different fabrics. IEEE J Biomed Health Inform. 2019 23(6):2417–2427. (11) Ohmura K, Minami T, Yanagi M, Mori N, Nakamura T, Masubuchi Y. Characterization of transitional behavior of the facial wash foams via dynamic viscoelastic measurements. Nihon Reoroji Gakkaishi. 2015 43(3_4):71–75. (12) Pourtois G, Grandjean D, Sander D, Vuilleumier P. Electrophysiological correlates of rapid spatial orienting towards fearful faces. Cereb Cortex. 2004 14(6):619–633.

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