Wrinkles around the eyes are the primary driver of age perception across five ethnic groups

Recent research published in the International Journal of Cosmetic Science provides evidence that wrinkles around the eyes are the primary physical feature driving perceptions of age and attractiveness across diverse ethnic groups. While factors such as skin color and gloss contribute to how healthy a woman appears, the depth and density of lines in the periorbital region consistently predict age assessments in women from Asia, Europe, and Africa.

The rationale behind this study stems from the fact that the skin around the eyes is structurally unique. It is significantly thinner than facial skin in other areas and contains fewer oil glands. This biological reality makes the eye area particularly susceptible to the effects of aging and environmental damage.

In addition to its delicate structure, the skin around the eyes is subjected to constant mechanical stress. Humans blink approximately 15,000 times per day, and these repeated muscle contractions eventually lead to permanent lines. Previous surveys have indicated that women worldwide consider under-eye bags, dark circles, and “crow’s feet” to be among their top aesthetic concerns.

However, most prior research on this topic has focused on specific populations or general facial aging. It has remained unclear whether specific changes in the eye region influence social perceptions in the same way across different cultures. The authors of the current study aimed to determine if the visual impact of periorbital skin features is consistent globally or if it varies significantly by ethnicity.

To investigate this, the researchers utilized a multi-center approach involving participants and assessors from five distinct locations. Data collection took place in Guangzhou, China; Tokyo, Japan; Lyon, France; New Delhi, India; and Cape Town, South Africa. The team initially recruited 526 women across these five locations to serve as the pool for the study.

From this larger group, the researchers selected a standardized subset of 180 women to serve as the subjects of the analysis. This final sample included exactly 36 women from each of the five ethnic groups. The participants ranged in age from 20 to 65 years, allowing for a comprehensive view of the aging process.

The researchers recorded high-resolution digital portraits of these women using a specialized system known as ColorFace. This equipment allowed for the standardization of lighting and angles, which is essential for accurate computer analysis. The team then defined two specific regions of interest on each face for detailed measurement.

The first region analyzed was the area directly under the eyes, which included the lower eyelid and the infraorbital hollow. The second region was the area at the outer corners of the eyes where lateral canthal lines, commonly known as crow’s feet, typically develop. The researchers used digital image analysis software to objectively quantify skin characteristics in these zones.

For the region under the eyes, the software measured skin color, gloss, skin tone evenness, and wrinkles. Skin color was broken down into specific components, including lightness, redness, and yellowness. Gloss was measured in terms of its intensity and contrast, while tone evenness was calculated based on the similarity of adjacent pixels.

For the crow’s feet region, the analysis focused exclusively on the measurement of wrinkles. The software identified wrinkles by detecting lines in the image that met specific criteria. The researchers quantified these features by calculating the total length of the wrinkles, their density within the region, and their volume.

To determine how these objective features translated into social perceptions, the study employed a large panel of human assessors. The researchers recruited 120 assessors in each of the five study locations, resulting in a total of 600 raters. These assessors were “naïve,” meaning they were not experts in dermatology or cosmetics.

The assessors were matched to the participants by ethnicity. For example, Chinese assessors rated the images of Chinese women, and French assessors rated the images of French women. Each assessor viewed the digital portraits on color-calibrated monitors.

They were asked to rate each face for perceived age, health, and attractiveness. These ratings were given on a continuous scale ranging from 0 to 100, where 0 represented a low attribute score and 100 represented a high attribute score. The researchers then used statistical methods to identify relationships between the objective skin measurements and the subjective ratings.

The results revealed distinct biological differences in how skin ages across the different groups. For instance, Indian and South African women tended to have lower skin lightness scores under the eyes compared to Chinese, Japanese, and French women. South African women also exhibited the highest density of wrinkles in the under-eye region among all groups.

Regarding the crow’s feet region, the analysis showed that South African, Chinese, and French women had similar levels of wrinkling. These levels were notably higher than those observed in Indian and Japanese women. This finding aligns with some previous research suggesting that wrinkle onset and progression can vary significantly based on ethnic background.

Despite these physical differences, the study found strong consistencies in how these features influenced perception. When looking at the full sample, wrinkles in both the under-eye and crow’s feet regions showed a strong positive correlation with perceived age. This means that as wrinkle density and volume increased, assessors consistently rated the faces as looking older.

On the other hand, wrinkles were negatively correlated with ratings of health and attractiveness. Faces with more pronounced lines around the eyes were perceived as less healthy and less attractive. This pattern held true regardless of the ethnic group of the woman or the assessor.

The study also highlighted the role of skin gloss, or radiance. Higher levels of specular gloss, which corresponds to the shine or glow of the skin, were associated with perceptions of better health and higher attractiveness. This suggests that skin radiance is a universal cue for vitality.

In contrast, skin tone evenness showed a more complex relationship. While generally associated with youth and health, it appeared to be a stronger cue for health judgments than for age. Uneven pigmentation and lower skin lightness were linked to lower health ratings, particularly in populations with darker skin tones.

Regression analyses allowed the researchers to determine which features were the strongest predictors of the ratings. For perceived age, wrinkles in the crow’s feet region emerged as a significant predictor for all five ethnic groups. This confirms that lines at the corners of the eyes are a primary marker used by people to estimate a woman’s age.

For Japanese and French women, wrinkles specifically under the eyes provided additional information for age judgments. This suggests that in these groups, the under-eye area may contribute more distinct visual information regarding aging than in other groups.

When predicting perceived health, the results were more varied. While wrinkles remained a negative predictor, skin color variables played a more prominent role. For Indian women, lighter skin in the under-eye region was a significant positive predictor of rated health.

Similarly, for South African women, skin yellowness was a positive predictor of both health and attractiveness ratings. This indicates that while wrinkles drive age perception, color cues are vital for judgments of well-being in these populations. The researchers posit that pigmentary issues, such as dark circles, may weigh more heavily on health perception in darker skin types.

An exception to these specific predictive patterns was observed in the French group regarding health ratings. While the overall statistical models were effective, no single skin feature stood out as a solitary predictor for health judgments in French women. This implies that French assessors might use a more holistic approach, combining multiple features rather than relying on a single cue like wrinkles or color.

The study has certain limitations that warrant mention. The sample size for the specific sub-group analyses was relatively small, with only 36 women per ethnicity. This reduces the statistical power to detect very subtle differences within each group.

Additionally, the study relied on static digital images. In real-world interactions, facial dynamics and expressions play a major role in the visibility of crow’s feet and other lines. Future research could investigate how movement influences the perception of these features.

The study, “Effects of under-eye skin and crow’s feet on perceived facial appearance in women of five ethnic groups,” was authored by Bernhard Fink, Remo Campiche, Todd K. Shackelford, and Rainer Voegeli.