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New research published in Perception indicates that the color of a person’s hair and the background behind them can change how other people perceive their skin. By altering the visual contrast around a face, scientists found that darker hair and black backgrounds tend to make facial skin appear more even. The findings suggest that everyday styling choices have visual effects that may influence how healthy and attractive a person appears to others.
The central focus of this research is perceived skin evenness, which refers to how uniform a person’s skin color and surface texture appear to an observer. When skin has a steady distribution of color and lacks bumps, spots, or wrinkles, observers tend to judge the face as younger, healthier, and more attractive. Beyond physical attractiveness, observers often link smooth skin to abstract social traits like trustworthiness and competence. Because these social judgments carry heavy weight in daily life, understanding exactly what makes skin look even is an active area of study.
Researchers already know that the biological condition of the skin plays a primary role in how it looks. But human visual perception is complex, and the appearance of skin is also swayed by the features directly next to it. Past work demonstrates that increasing the visual contrast between the skin and facial features like the eyes, lips, and eyebrows actually makes the skin itself look more even. This visual illusion happens even when dark makeup is applied only to the eyes and lips, leaving the skin entirely untouched.
“Previous research has found that increased contrast between skin and adjacent surfaces increases perceived skin evenness,” lead researcher Carlota Batres, an associate professor of psychology at Franklin & Marshall College and the director of the Preferences Lab, told PsyPost. “Our study aimed to examine whether this effect can be extended to situations where the entire face is left untouched and contrast is modified by increasing or decreasing the luminance of surfaces surrounding the face.”
This visual effect is thought to stem from a basic processing mechanism in the brain known as contrast gain control. In simple terms, this means the human visual system evaluates the brightness and texture of a specific region relative to its immediate surroundings. The research team, which also included Richard Russell at Gettysburg College, wanted to know if this visual mechanism operates over larger spatial distances. They set out to test whether modifying the contrast entirely outside the face, by changing hair lightness or background color, would still trick the eye into seeing more even skin.
The neurological reach of this mechanism was previously unclear. “The effects of contrast gain control are believed to operate within but not across cortical hypercolumns, meaning I was not sure this effect would be present across greater spatial expanses such as the contrast surrounding the face,” Batres explained. “In other words, previous studies have addressed contrast within the face, and here we aimed to address contrast outside the face.”
To explore this, the researchers set up two separate experiments. In the first experiment, they gathered photographs of 45 white women ranging in age from 19 to 79. All the women were photographed facing forward with neutral expressions. The scientists selected images where the hair could be entirely masked by an oval border, leaving only the facial skin and features visible.
For each face, the researchers created two versions. One version placed the face against a high-contrast black oval background. The other version placed the face against a low-contrast, skin-colored background, which was created by averaging the actual skin colors from the cheeks of the photographed faces. A group of 61 participants recruited online viewed these 90 images one by one in a random order.
For each image, participants rated the evenness of the person’s skin on a scale from one to seven, where one meant very uneven and seven meant very even. The participants were instructed to look for similar coloration throughout the face and a lack of blemishes, spots, and blotchiness.
The results of the first experiment showed that the background color shifted how observers rated the skin. When faces were presented against the high-contrast black background, their skin was rated as more even, scoring an average of 4.18 out of 7. In comparison, the exact same faces received an average evenness score of 3.95 when presented against the low-contrast skin-colored background. This effect appeared whether the face being judged belonged to a younger woman under 30 or an older woman over 30.
The second experiment aimed to test this visual effect using a more natural, everyday adjustment. The researchers selected a new set of photographs featuring 41 white women, again spanning ages 19 to 79. This time, they specifically chose images with a sharp visual boundary between the person’s hair and their skin.
Using photo editing software, the scientists slightly altered the lightness of each woman’s hair. They created two versions of each face: one where the hair was lightened by a small set amount, and one where the hair was darkened by the same amount. A new group of 80 online participants rated the skin evenness of these 82 images using the same one to seven scale from the first experiment.
Just like the background colors, the hair lightness shifted the participants’ perception of the skin. Faces with artificially darkened hair were rated as having more even skin, with an average score of 4.06. When the exact same faces were shown with lightened hair, the average skin evenness score dropped slightly to 4.01, representing a small difference of just 0.05 points on the seven-point scale.
When the researchers separated the faces by age, they noticed a difference in how hair lightness affected perception. The visual trick was not statistically significant for the younger faces, whose skin was generally already quite uniform. However, for the older faces, the darkened hair made the skin appear more even. The researchers suspect this is because the hair manipulation was a very mild adjustment compared to the stark black background used in the first study, making its subtle effect only detectable on faces that started with more uneven skin.
“Many practices of grooming and personal decoration involve surfaces adjacent to the skin, such as hair, clothing, or other backgrounds, and the results of this study show that these social practices have perceptual consequences related to skin appearance,” Batres noted. The results confirm “that the contrast between the facial skin and the surfaces surrounding the face, whether background color or hair color, influence perceived skin evenness.”
These modest visual effects offer a potential scientific explanation for certain fashion and grooming preferences. Past research shows that women are often rated as more attractive when wearing black clothing. The new findings suggest this boost in attractiveness might happen partly because dark clothing provides high contrast against the skin, making the face look more even and healthier. Similarly, women are often rated as more attractive when wearing their hair down rather than pulled back. Hair framing the face increases the visual contrast directly next to the skin, which might naturally boost perceived skin evenness.
As with all research, there are a few things to keep in mind. The study relied exclusively on photographs of lightly pigmented white women, meaning the results might not automatically apply to faces of other races or genders. It remains unknown if this contrast trick works in the exact same way for people with darker skin tones, or if different hair and background combinations might be needed to achieve the highest contrast.
Another point to consider is the subtle nature of the hair edits in the second experiment. The researchers only adjusted how light or dark the hair was, keeping the original color family intact. “Our hair manipulation was slight, and it would be interesting for future studies to further examine this effect,” Batres said.
Future studies could test more dramatic hair changes, such as shifting entirely from blonde to black, to see if more extreme contrast creates a stronger illusion of even skin. This could be done “by changing the hair color altogether to one that is high contrast relative to each face’s skin tone versus one that is low contrast relative to each face’s skin tone,” Batres added. The researchers also hope to test other common facial accessories, like glasses, hijabs, or jewelry, to see how they interact with skin perception.
The study, “Perceived skin evenness is influenced by background color and hair color,” was authored by Carlota Batres and Richard Russell.