Our face is the most powerful tool for socializing. It conveys a great deal of information about ourselves. For this reason, we regularly check our own reflections in the mirror in everyday life. Previous studies have revealed that context and sensory stimuli alter face perception and evaluation. However, it is unclear how external sensory stimuli change neural processing of self-face perception and evaluation. This study investigated how odor alters self-face perception and evaluation using the mean amplitude of event-related potentials (ERP) and post-survey ratings. Thirty participants showed differences in the mean ERP amplitudes in the frontal region of the left hemisphere after the onset of self-face perception when exposed to a pleasant odor (lavender) or an unpleasant odor (isovaleric acid). The responses also differed depending on sex, body mass index (BMI), and self-esteem. The self-face perception and evaluation response were more sensitive to odors in females than in males. Participants with high BMI or high self-esteem showed little difference between the presented odors. Interestingly, the neural modulation patterns in response to both odors were isovaleric acid–like in the high-BMI group but lavender-like in the high-self-esteem group. These results indicate that accumulated feelings toward the self or sensitivity to the odor stimuli may produce different self-face perceptions and evaluations. The results will help us understand the modulation of neural activity patterns by odors during self-perception and evaluation. Furthermore, they demonstrate distinct responses to odor stimuli according to individual features such as sex, BMI, and self-esteem. This study could be used to develop neuro-cosmetics or enhance social well-being.
Table Of Contents
List of Contents ABSTRACT i List of Contents ii List of Tables v List of Figures vi Ⅰ. Introduction - 1 - 1.1 Overview of this study - 1 - 1.2 Theoretical background of this study - 6 - 1.2.1 Importance of making good social relationships - 6 - 1.2.2 Central roles of self-face perception processing in social relationships - 6 - 1.2.3 Distinct neural patterns: self-face vs. non-self-face - 8 - 1.2.4 Odor stimuli - 11 - 1.2.5 Sex, BMI, and self-esteem - 13 - Ⅱ. Materials & Methods - 17 - 2.1 Participants - 17 - 2.2 Stimulus - 20 - 2.3 Experimental scheme - 22 - 2.4 Questionnaires - 25 - 2.5 EEG data analysis - 31 - 2.6 Statistical analysis - 40 - Ⅲ. Characterization of self-face perception and evaluation depending on sex, BMI, and self-esteem - 41 - 3.1. Significance & Hypothesis - 41 - 3.2 Results - 42 - 3.2.1 Self-face evaluation ratings - 42 - 3.2.2 Neural processing of self-face - 44 - 3.2.3 Effects of sex, BMI, and self-esteem on self-face processing - 46 - 3.3. Discussion - 51 - Ⅳ. Effects of odor stimuli on self-face perception and evaluation - 53 - 4.1 Significance & Hypothesis - 53 - 4.2 Results - 54 - 4.2.1 Odor characteristic ratings - 54 - 4.2.2 Self-face evaluation ratings after odor priming - 59 - 4.2.3 Neural processing of self-face after odor priming - 61 - 4.2.4 Correlation between odor perception and self-face evaluation - 65 - 4.3 Discussion - 67 - Ⅴ. Effects of odor stimuli on self-face perception and evaluation depending on sex, BMI, and self-esteem - 70 - 5.1 Significance & Hypothesis - 70 - 5.2 Results - 71 - 5.2.1. Sex difference - 71 - 5.2.2.BMI - 77 - 5.2.3 Self-esteem - 81 - 5.2.4 BMI & Self-esteem - 85 - 5.3 Discussion - 88 - VI Conclusion - 90 - Reference - 92 - 요 약 문 - 104 -