A real-life illusion of assimilation in the human face: eye size illusion caused by eyebrows and eye shadow

Upper eyelid morphology and age-related changes in Japanese and Chinese females

BACKGROUND

Many consumers use cosmetic eye products to counteract age-related changes in appearance. Measurements of eyelid shape in Asian women have been reported in the frontal view or 45-degree profile only. The aim of this study was to describe morphological characteristics of the upper eyelid in Japanese and Chinese females from the frontal and profile aspects and examine morphological changes with age.

MATERIALS AND METHODS

Standardized digital photographs of 772 Japanese and 346 Chinese women (15-79 years of age) were acquired in frontal and 90-degree profile aspects. Eleven upper eyelid parameters (e.g., width, length, depth, aperture, and curvature) were measured using image analysis to determine age-related changes and compare by ethnicity.

RESULTS

Eyelid width, area between eyebrow and eyelid, and eyelid curvature were comparable for both ethnicities under age 40, but the aging effect was more pronounced in Chinese subjects. Eyelid height, depth, and upper eyelid aperture angle were also comparable for both ethnicities under age 40, but the aging effect was more evident in Japanese subjects. Upper eyelid incline angle, eye orientation, and upper eyelid protrusion angle changed comparably with age for both ethnicities. No prominent age-related changes were evident for eyelid length or area between eyebrow and eye with the eye closed.

CONCLUSION

Upper eyelid morphology changes with age in Japanese and Chinese females, starting around 40 years of age. Ethnic differences are limited in younger age groups but become more prominent with age. The findings suggest that aging affects some upper eyelid features earlier than others.

Defining Ideal Double Eyelids With a Morphometric Analysis in Asians

BACKGROUND

Double eyelids are always considered crucial aesthetic symbols. Despite numerous studies conducted on the attractiveness of double eyelids, there remains a dearth of research on quantitative and morphological evaluation of ideal double eyelids.

OBJECTIVES

In this we study aimed to investigate the optimal height and morphological characteristics of ideal double eyelids.

METHODS

Participants were presented with a total of 9 images, consisting of 1 single eyelid image and 8 double eyelid images, featuring 2 distinct shapes and 4 varied pretarsal shows. Respondents were instructed to assign scores ranging from 1 (least attractive) to 5 (most attractive) for each image. Subsequently, the scores for each image were analyzed based on population demographics, followed by the calculation of aesthetic metrics.

RESULTS

The whole cohort deemed images with a 2-mm fold to be more attractive than 1 mm (P < .001), followed by 3 mm and 0 mm (single eyelid), and finally, 4 mm. Morphologically, significant differences were found between images with the same pretarsal shows of 3 mm (P < .001) and 4 mm (P = .026). Most subgroup analysis results were aligned with those of the cohort, with gender being the most significant factor in distinguishing double eyelid aesthetics. Additionally, aesthetic characteristics of 2-mm folds were found to be comparable to appealing double eyelids in previous studies.

CONCLUSIONS

In this study we validated the optimal heights and morphology of double eyelids, thereby addressing the existing gap in aesthetic studies on double eyelids. These findings hold significant implications for surgical planning, effect assessment, and other periocular procedures related to upper blepharoplasty.

LEVEL OF EVIDENCE: 4

Eye size recognition of self and others among people with self-face dissatisfaction

Previous studies have shown that individuals visually recognize their eye size as larger than the actual. However, it is unclear whether this cognitive tendency occurs in people with high self-face dissatisfaction. Therefore, this study aimed to investigate whether the cognitive size of one's own and others' eyes differs according to the degree of self-face dissatisfaction. Participants comprised 32 college students (5 males, 27 females; age: 21.3 ± 2.11) who completed the Face Dissatisfaction Scale (FDS) and a face recognition memory task. The task was to choose whether their or their friends' eyes in the face photos with changed eye size were larger or smaller than their actual eye size. The cognitively equivalent eye size to the actual one was estimated from a psychophysical function. We conducted a correlation analysis of the total scores on the FDS and the point of subjective equality (PSE) of eye size. We found a high negative correlation between the FDS and the PSE of own eye size. There was also a high positive correlation between the FDS and the PSE for all others' faces. Thus, high self-face dissatisfaction is differentially associated with cognitive distortions of the face, depending on whether it is self or other.

Thinking about the bigger picture: Influence of holistic processing on the dishware size effect

Individuals vary in the extent to which they engage in holistic and analytic information processing styles. Holistic processing involves focusing on the interconnectivity and relatedness of items being evaluated, while analytic processing involves focusing on items being judged as discrete elements and independent of context. We examined the contribution of these basic processing styles to the dishware size effect, which proposes that food consumption patterns may be influenced by the size of the dishware (i.e., larger plates increase the amount of food consumed). We observed that participants self-served and consumed more food when using and eating from a larger plate (LP) compared with a smaller plate (SP) (p≤0.01). Importantly, participants who reported greater levels of holistic information processing related to attitudes towards contradictions and attention allocation exhibited smaller variations in portions of food self-served and consumed based on the dishware size used (SP vs. LP). These findings suggest that the susceptibility of individuals to the dishware size effect may be associated with an individual's dispositional tendency to process information in a holistic (vs. analytic) manner.

Cosmetic makeup enhances facial attractiveness and affective neural responses

Although it is well established that cosmetic makeup enhances perceived facial attractiveness, few studies have examined whether facial makeup modulates neural responses to face images. This study investigated behavioral and attractiveness-related brain responses to self-applied makeup, focusing on the N170, early posterior negativity, P300, and late positive potential components of event-related brain potentials. A total of 77 Japanese women participated in two experiments (N = 34 and 43 for Experiments 1 and 2, respectively). Experiment 1 assessed the effects of self-applied makeup on attractiveness-related event-related potential amplitudes using facial images during a makeup identification task in which makeup was directly relevant to task demands. Experiment 2 examined the effects of self-applied makeup using images of one’s own face and another female’s face when performing a gender classification task, where the presence of makeup had no explicit connection to facial gender classification. In both experiments, faces with makeup were rated as more attractive and elicited more negative early posterior negativity and more positive late positive potential components, regardless of the participant’s own face or another person’s face. These findings suggest that people are spontaneously motivated to pay visual attention to faces with makeup, which supports the idea that makeup adds reward value to the facial appearance of the human. Moreover, neural evidence empirically confirmed that the benefits of makeup are not just limited to how others see your face but also extend to how you see your own face.

Who's Behind the Makeup? The Effects of Varying Levels of Cosmetics Application on Perceptions of Facial Attractiveness, Competence, and Sociosexuality

Research has demonstrated a positive effect of makeup on facial attractiveness (Cash et al., 1989; Russell, 2003; Etcoff et al., 2011). Makeup has also been found to influence social perceptions (Etcoff et al., 2011; Klatt et al., 2016). While researchers have typically compared faces with makeup to faces without makeup, we propose that perceived effects will differ based on the amount of makeup that is applied. To test the effects of varying levels of makeup on perceived facial attractiveness, competence, and sociosexuality, participants assessed 35 faces with no makeup, light makeup, and heavy makeup; makeup was self-applied by participants, not applied by a makeup artist or the experimenter. Participants rated faces with makeup (either light or heavy) as more competent than those without makeup. In addition, participants rated faces with heavy makeup as significantly higher in attractiveness and sociosexuality than faces with light makeup. These results differ from previous research findings that faces with light makeup (applied by professional makeup artists) are perceived as most attractive. Our results suggest that when makeup is self-applied, faces with heavy makeup are perceived as more attractive and sociosexual than faces with light makeup, and faces with any level of makeup are rated as more competent.

Applying Computer Graphic Design Software in a Computer-Assisted Instruction Teaching Model of Makeup Design

Methods for teaching contemporary makeup design involve drawing on paper, which requires considerable time and is difficult to edit. To change the makeup color, one must redraw their entire makeup design again, which is both inefficient and not environmentally friendly. Furthermore, design drawings are difficult to preserve. However, computer graphic design has not been used in the teaching of makeup design drawing; instead, learners rely on knowledge from professors and the experience they accumulate through practicing drawing on paper. Computer graphic design software allows users to experiment with various color designs, lines, and shading options before finalizing their makeup design. Thus, this study sought to employ such technology to improve upon conventional hand drawing practice techniques. The experiment was divided into a preliminary experiment and main experiment, where a two-stage questionnaire was conducted. In the preliminary experiment, the researchers compared the time required to complete the hand-drawn and computer-drawn makeup designs. The results revealed that the hand-drawn designs required almost double time than computer-drawn designs to complete. Additionally, time-lapse photography was taken during the computer drawing process; the photos were used to explain—to participants in a digital drawing group in the main experiment—the digital drawing makeup design procedures and the required operation time. The first stage of the main experiment comprised a brush selection experiment. The participants, 39 students from a cosmetology department, completed a Likert-scale questionnaire. They also performed item analysis to discuss and select drawing tools from a graphic design software, which met the requirements for makeup design pertaining to the eyebrow, eyeshadow, eyeliner, blush, nose contour, and lips. The software allowed the students to experiment with different colors in their design and immediately displays the results. In the second stage, an experiment on optimizing brush arrangements was performed by 10 experts, all of whom were teachers from the department of cosmetology, had at least 5 years of teaching experience, and had obtained a Level B (advanced level) Beauty Technician Certificate. Data from a Likert-scale questionnaire were analyzed and narrative analysis was conducted to determine the rating and evaluation priorities for standards pertaining to the eyebrows, eyeshadow, eyeliners, blush, nose contour, and lips. The requirement for design symmetry was achieved by using the mirror function of the software. This function was useful: it enabled students to complete their makeup design in approximately half the time. This study transformed the conventional learning method through interdisciplinary integration, established novel and innovative teaching models, and provides crucial insights into future research on improving teaching practice.

Viewpoint Invariance of Eye Size Illusion Caused by Eyeshadow

Previous research found that application of eyeshadow on the upper eyelids induces overestimation of eye size. The present study examined whether or not this eyeshadow illusion is dependent on viewpoint. We created a three-dimensional model of a female face and manipulated the presence/absence of eyeshadow and face orientation around the axis of yaw (Experiment 1) or pitch (Experiment 2) rotation. Using the staircase method, we measured perceived eye size for each face stimulus. Results showed that the eyeshadow illusion occurred regardless of face orientation around axes of both yaw and pitch rotations. Crucially, the illusion’s magnitude did not vary across face orientations; lack of interaction between the illusion’s magnitude and face orientation was confirmed by small values of Bayes factors. These findings ruled out the hypothesis that eyeshadow serves as a depth cue and leads to overestimation of eye size due to size-distance scaling. Alternatively, the present findings suggest that the eyeshadow illusion can be well explained by the assimilation between the eyes and eyeshadow, which also facilitates assimilation between the eyes and eyebrows. Practical implications and the present findings’ generalizability are also discussed.

The Role of Regional Contrast Changes and Asymmetry in Facial Attractiveness Related to Cosmetic Use

This study collected behavioral data for testing how regional contrast changes due to the addition of cosmetics would affect attractiveness ratings. In addition, we used an established model of asymmetry to look for a correlation between changes in attractiveness related to the application of cosmetics to specific regions of the face and changes in symmetry. Using this asymmetry model we compared female faces with and without makeup. Specifically, we used a highly controlled set of grayscale faces in which makeup application was standardized to explore these issues from a perceptual perspective. The human data showed that adding upper eye makeup significantly increased attractiveness ratings. In contrast, increases in contrast to the lower eyes and lips did not lead to increases in attractiveness ratings; application of cosmetics to the lower eyes led to a significant decrease in attractiveness. We found that for the makeup condition that led to increased attractiveness, asymmetry did not change significantly when makeup was applied to the female faces. This suggests a role for mechanisms other than symmetry related to increases in attractiveness related to makeup use in females.

The boundary of holistic processing in the appraisal of facial attractiveness

Facial attractiveness is often studied on the basis of the internal facial features alone. This study investigated how this exclusion of the external features affects the perception of attractiveness. We studied the effects of two most commonly used methods of exclusion, where the shape of an occluding mask was defined by either the facial outline or an oval. Participants rated attractiveness of the same faces under these conditions. Results showed that faces were consistently rated more attractive when they were masked by an oval shape rather than by their outline (Experiment 1). Attractive faces were more strongly affected by this effect than were less attractive faces when participants were able to control the viewing time. However, unattractive faces benefited more from this effect when the same face stimuli were presented briefly for only 20 ms (Experiment 2). Further manipulation confirmed that the effect was mainly due to the occlusion of a larger area of the external features rather than the regular and symmetrical features of the oval shape (Experiment 3) or lacks contextual cues about the face boundary (Experiment 4). The effect was only relative to masked faces, with no advantage over unmasked faces (Experiment 5), and is likely a result of the interaction between the shape of a mask and the internal features of the face. This holistic effect in the appraisal of facial attractiveness is striking, because the oval shape of the mask is not a part of the face but is the edge of an occluding object.

Chen's Double Eyelid Fold Illusion: An Eye Size Assimilation Illusion Induced by a Supratarsal Fold in the Brow-Eye Unit, A Preliminary Report

BACKGROUND

Double eyelidplasty can enhance the eye size and facial attractiveness of Asian individuals with single eyelids. The authors hypothesize that a supratarsal fold can induce an eye size assimilation illusion to enhance eye dimensions and aesthetics, and seek to define the optimum vertical proportion between a supratarsal fold and the eye fissure associated with maximal induction of the size assimilation illusion.

METHODS

A photometric study of the replicated photographs of ten female Taiwanese patients after double eyelidplasty was designed. Each photograph was edited by shifting the supratarsal folds vertically at a regular fold/eye ratio increment of 0.1. The perceived attractiveness of edited photographs of each patient was rated by 100 adult observers using a score of 1-5. The palpebral parameters were measured and analyzed.

RESULTS

The mean rating score increased gradually when a supratarsal fold was added and peaked when the fold/eye ratio was 0.3 and the mean Chen's double eyelid fold ratio was 0.631 ± 0.023. After the peak, the mean score decreased gradually and was lower than the photograph without a fold when the fold/eye ratio exceeded 0.5 and the mean Chen's ratio exceeded 0.729 ± 0.027.

CONCLUSION

Within the optimal ranges of the fold/eye ratio and Chen's double eyelid fold ratio, eyes are perceived as larger and more attractive due to a hybrid presentation of two interdependent eye size assimilation illusions induced by a supratarsal fold in the brow-eye unit. "Chen's double eyelid fold illusion" is proposed to describe this complex visual phenomenon.

LEVEL OF EVIDENCE IV

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Effects of Lip Color on Perceived Lightness of Human Facial Skin

Whereas geometric illusions in human faces have been reported by several studies, illusions of color or lightness in faces have seldom been explored. Here, we psychophysically investigated whether lip color influences facial skin’s perceived lightness. Results of Experiment 1 demonstrated that redder lips lightened and darker lips darkened the perceived complexion. These lightness or darkness inducing effects differ from the classical illusion of lightness contrast in nonface objects for two reasons. First, illusory effects are more assimilative than contrastive. Second, the inducing area (i.e., lips) is much smaller than the influenced area (facial skin). Experiment 2 showed that the assimilative lightness induction was caused by holistic processing of faces. This is the first study to scientifically substantiate the claim of cosmetics manufacturers and makeup artists that lip colors can alter perceived facial skin color. Implications for face perception, lightness illusion, and perceptual effects of cosmetics are discussed.

Chen's Double Eyelid Fold Ratio

BACKGROUND

Double eyelidplasty can construct palpebral folds and enhance beauty perception for Asians with single eyelids. A new palpebral parameter for the quantitative interpretation of surgical outcomes is proposed on the basis of a photometric study of the altered proportions of Asian eyes after double eyelid operation.

METHODS

A total of 100 Asian adults with single upper eyelids who were satisfied with the enlarged eyes by operation were included in the study. A retrospective measurement of palpebral parameters in the frontal profile both preoperatively and 6 months postoperatively was performed. The proportions of various parameters in the eyebrow-eye aesthetic unit were calculated and analyzed.

RESULTS

Double eyelidplasty can augment the vertical dimension of palpebral fissure by 27.9% increase on average. The vertical ratio of palpebral fissure to the eyebrow-eye unit is augmented by 34.4% increase. The vertical ratio of the subunit below double eyelid fold peak to the unit is augmented by 82.6% increase.

CONCLUSIONS

Double eyelidplasty can substantially enlarge the vertical dimensions of the eyes of Asians with single eyelids. The eyes are perceived to be larger because of the visually assimilated illusion of the superimposed eyelid fold and the relative proportions of the eyebrow-eye unit. The authors propose using a vertical ratio of the subunit below double eyelid fold peak in the eyebrow-eye unit to measure the visually perceived proportion of the eye in the unit. This ratio can be applied clinically for a quantitative evaluation of the surgical outcome after double eyelidplasty.