This study was conducted to examine the effects of independently manipulated luminance contrast (facial contrast) of facial parts on appearance impressions and to explore factors contributing to attractiveness. We created high-contrast and low-contrast images of faces with respect to the surrounding skin for the eyebrows, eyes, nose, and mouth of an androgynous face based on average images of male and female faces. After 82 university students were presented with side-by-side stimuli of high-contrast and low-contrast faces including each of the four parts, each participant was asked to judge the depicted person's attractiveness, femininity, and health. Results obtained using Scheffe's method of paired comparisons indicated a significant sex × face parts (contrast manipulation site) interaction. The subtest results showed the following characteristics. First, women rated faces with high mouth contrast as higher for attractiveness, femininity, and healthiness, and judged faces with low nose contrast to be attractive. They also judged faces with high eyebrow contrast as healthy. Men rated faces with high eye contrast as higher for attractiveness, femininity, and healthiness, and judged faces with lower nose contrast to be more feminine. Overall, no correlation was found between attractiveness, femininity, and healthiness. Regarding correlations by gender and facial parts, significant positive correlations were found between attractiveness and femininity, attractiveness and femininity of the eyebrows and mouth, and between attractiveness and healthiness of eyes and nose among men, but no significant correlation was found among women.

When judging attractiveness, women were found to be influenced significantly by the mouth contrast. Men were influenced by the eye contrast. Correlations between the impressions revealed differences depending on the evaluator gender. The findings suggest the importance of gender differences when judging facial attractiveness.

For this study, we re-examined and resolved a problem raised by an earlier study, which indicated that the most beautiful eye-mouth spatial arrangement differs depending on the mouth width. Specifically, we set three levels of mouth width as wide, average, and narrow, and conducted an experiment using more appropriate stimuli and image-processing methods. Nine stimuli were created by altering the inter-eye distance (discrete, average, and concentrated) and the eye-mouth distance (high, average, and low). Ratings of facial beauty were obtained using Thurston's paired comparison method. The results indicated that, irrespective of the mouth width, the highest beauty rating was assigned for faces with average inter-eye distance and low eye-mouth distance. Earlier studies found that the average spatial arrangement balance and a high eye-mouth distance were regarded as beautiful for wide-mouth faces. However, based on the more appropriate method used for this study, a face with a child-like placement balance with low eye-mouth distance, as in the baby schema, was judged as the most beautiful, irrespective of the mouth width.

In Japan, the concept of "omokage" has long been used in relation to face, etc. Omokage (looks, trace, vestige, etc.) is a subjective experience that emerges through the mutual evaluation of similarities between perceived face and remembered face.

In this study, we first attempted to visualize "faces with the omokage" using the "reverse correlation method", a data-driven exploratory method (Study 1). Specifically, I assigned a task to participants in which they were asked to select an image from among multiple child face images that felt the current omokage of a specific celebrity. As a result, by repeating the process of finding the omokage of the celebrity in the child face images, "a child face with the current omokage of the celebrity" could be visualized with a certain degree of accuracy. Furthermore, the analysis of the pixel regions that were given particular importance in image selection showed that the visual features that determine the omokage were distributed among features such as the eyes, mouth, and contour.

Next, I conducted an evaluation survey to investigate whether the visualized face images could be perceived by a third party as "a face with the celebrity's omokage", and how similar they were to the celebrity's actual childhood faces (Study 2). The results showed that the images visualized based on high accuracy were also evaluated as "face with the omokage" by third parties, indicating that the omokage can be shared to some extent within a population. Furthermore, it was also shown that when based on high accuracy, it is possible to generate a face that is more strongly reminiscent of the omokage than the celebrity's actual childhood face.

The purpose of the present study was to examine the effect of colors of eyeliner on the perceived size of eyes and eye- shaped figures. The colors of eyeliner were none, yellow, orange, pink, red, purple, blue, green, brown, and black. There were two ways of drawing eyeliner: upper+lower 1/3 condition and full-surrounding condition. The task of participants was to report a numerical value that corresponded to the perceived size of the whole eye (or eye-shaped figure) with or without eyeliner (or imitated eyeliner), when the perceived size of the whole eye of the face image (or figure) without eyeliner (or imitated eyeliner) was assigned as 100 (i.e. magnitude estimation method). The results of Experiment 1 showed that the color of the eyeliner significantly affected the perceived size of the eyes on the face figures. The results of Experiment 2 showed that the eyeliner imitated color significantly affected the perceived size of eye-shaped figures. The tendencies of the effect of color of eyeliner and eyeliner imitated color on the perceived size of eyes and eye-shaped figures differed, respectively. These results suggested that the effect of color of eyeliner on the perceived size of eyes was a face specific phenomenon.

The appearance of the lips changes with age. However, it is unclear what kind of visible characteristics affect the apparent age of lips. The present study aimed to identify the factors that affect the apparent age of the lips and determine the impact of those factors. Study participants were asked to state their impressions of various pictures of the lips of adult women and estimate the apparent age of the lips. Factor analysis of the participants' rating values yielded four factors: complexion, volume, shape, and wrinkles. Multiple regression analyses indicated that regarding apparent age of the lips, the impact of complexion and volume was significant. Conversely, the effect of shape and wrinkle was not significant.

Literature has shown faces are an important source of information to evaluate someone's age. However, it has not been fully understood how much each part of a face affects estimating his/her age and whether the face's gender affects it. Particularly, wearing sanitary masks has been too common during the COVID-19 pandemic to ignore its effect on our ability to age estimation. This study aimed to explore how masking any part of the face, i.e., forehead, eyebrows, eyes, nose, and mouth, affects age estimation with 33 undergraduate and graduate students. Participants were parallelly presented a facial picture each at a time along with the picture with a part of the face covered by a black rectangle, and asked for the age difference between the pictures. Results showed that participants evaluated both male and female pictures looked older in the eyes covered condition than in the other conditions, but there was sex difference in age estimation: Participants evaluated the female pictures with their forehead, nose, or mouth covered by the rectangles younger than the pictures with full face but no such effect was found for the male pictures. These findings suggest that parts of faces and their gender affect differently in age estimation, and women wearing sanitary masks could look younger than they are due to the cover of their noses and areas around mouths.

Caricaturized portraits (Nigaoe, in Japanese) have a long history in Japan, extending from Nise-e in the Heian period to the present day. In recent years, computerized Nigaoe have also been developed. Computerized Nigaoe present benefits of objective extraction and exaggeration of morphological differences of a model's face from an average face. Nigaoe produced by a human creator are drawn with some reflection of the model's personality obtained through comprehensive observation of a model. To develop a new method for creating Nigaoe images that incorporate these important benefits of both computer and human creators, the following stimuli of three types were created by collecting the Nigaoe of 12 models created by 22 artists: (1) Digitized Nigaoe created by tracing the original drawings (original Nigaoe); (2) Nigaoe averaged from the original Nigaoe of individual models (individual average Nigaoe); and (3) Nigaoe that are extracted, with differences exaggerated from the standard template that is a re-averaged "individual average Nigaoe" (exaggerated Nigaoe). When the degrees of similarity of these Nigaoe stimuli of three types were compared through experimentation, similarity was evaluated as reflecting the following order: (3) exaggerated Nigaoe>(2) individual average Nigaoe>(1) original Nigaoe. The results demonstrate that this newly developed Nigaoe creation method can accumulate human-drawn portraits using rudimentary drawing software.

In this study, we investigated the brain activity related to eyeshadow color preference using functional magnetic resonance image (fMRI). We also investigated gaze patterns during face perception both with and without face mask using eye tracker. Before performing fMRI, participants chose their favorite/neutral/unfavorite eyeshadow out of 10 different colors. Then their facial pictures applying each eyeshadow and also not applying eyeshadow for both with and without face mask, were prepared. Others' facial pictures applying same color of eyeshadows corresponds to each participant were used for control. In the fMRI scanner, participants rated the preference for each picture from 1 to 6 rating scale.

Behaviorally, we found significant difference in preference rating for favorite eyeshadow color compared to unfavorite color, specific to self-face picture. This eyeshadow color preference was coded in dorsal striatum, which may play roles in processing higher-order social reward and value. Also, the preference rating was higher for the self-face picture with face mask than without it when applying a favorite color of eyeshadow. Striatum and posterior cingulate cortex were related to this rating, suggesting that social reward and positive emotion were elicited by wearing a face mask. Moreover, the picture of self-face applying neutral color of eyeshadow was rated higher than applying unfavorite color, and nucleus accumbens was activated. It suggests that seeing unfamiliar looks with a new color of eyeshadow elicited a curiosity and motivation to try it.

Additionally, gaze patterns indicated that wearing face mask draw more attention to eye area compared to without it.

As remote control technology for hydraulic excavators continues to develop, the issue of visually induced motion sickness (VIMS) during operation has become a concern. One method of detecting VIMS is through biometric measurement, but the use of sensors can be burdensome, particularly for remote operation.

Therefore, this study focused on non-invasive facial analysis using an RGB camera and investigated changes in facial expressions during VIMS. With the participation of 11 healthy male subjects experienced in hydraulic excavator work, VIMS was subjectively evaluated on a five-point scale during simulated excavation work, and the Simulation Sickness Questionnaire (SSQ) was used to evaluate the subjects before and after the experiment. Facial expressions were analyzed using Google's Mediapipe FaceMesh, which extracted 468 facial feature points from the subjects' facial images during the work. Changes in facial feature points were compared with the subjective evaluation of VIMS.

Based on the SSQ, six participants experienced VIMS, and all of them showed changes in feature point coordinates near their cheeks. Additionally, for two participants, characteristic movements were observed near the nasolabial folds, where feature point coordinates moved away from the center of the face. This suggests that VIMS can be detected through changes in facial expressions.

In the future, we will collect more data for confirmation, and by combining this with instantaneous facial expression changes due to emotional changes, we may be able to detect negative facial expressions due to VIMS discomfort by combining it with the momentary facial expression changes caused by emotional changes. It is also necessary to distinguish negative facial expressions due to VIMS from those due to fatigue or decreased arousal caused by work.