Perceived age: Eyes, skin tone give away years

Key Points

International report - A person's perceived age depends largely upon the appearance of their periocular area and skin color, according to a recent study.

The study, moreover, shows that in estimating someone's age, older people focus on the lips, while younger people look to dark circles, nasolabial folds and brown spots.

"Makeup, cosmetic skincare and aesthetic surgical and nonsurgical procedures are different ways to address people's needs for a youthful appearance," says Christiane Bertin, M.D., research fellow with Paris-based Johnson & Johnson Consumer Products and lead author of the study.

"We believed that it would be helpful for skincare professionals to know the contribution of the different facial attributes to perceived age," she says.

Therefore, researchers recruited 48 graders (20 male, 28 female) to assess the impact of 23 skin attributes on the perceived ages of 173 women by looking at clinical photos. Researchers then studied the relationship between each attribute and perceived age using curve fitting.

More specifically, researchers used partial least square (PLS) regression models to characterize and understand the relationship between facial attributes and perceived age.

PLS regression gives an equation that relates the target (age, for example) to the explicative variables, and PLS is particularly recommended when the explicative variables are highly correlated, says Alex Nkengne, a scientist with Johnson & Johnson Consumer Products and a study co-author.

"In our case," Mr. Nkengne says, "the facial attributes that we measured are correlated between themselves. For example, wrinkles increase as the lips become thinner."

The weight of each variable or facial attribute in the PLS regression model characterizes its importance for the prediction of perceived age, Mr. Nkengne tells Dermatology Times.

Researchers also factored in the ages of graders themselves, whom they grouped into three categories: young (under 35 years old), middle-aged (35 to 50 years) and senior (more than 50 years).

"We built a PLS regression model between facial attributes and the perceived age given by each group of graders - young, middle-aged, old and all graders together. We defined the perceived age of an individual as her average age from all the graders within the group," Mr. Nkengne says.

Researchers then compared the relative contribution of each attribute, expressed as a percentage, to the prediction.

Researchers concluded that, overall, the appearance of the eye area and the uniformity of skin color are key attributes in perceived age. Their importance was actually overestimated by the graders, Mr. Nkengne says.

"Graders under age 35 are more driven by dark circles, nasolabial folds and brown spots, while older graders are more driven by lips' border definition, lip shape and the appearance of eye openings," he says.

"The importance of the eyes area was not surprising, since the eyes are considered attractive features in the face. The importance of skin color uniformity has also been recently demonstrated by another research team (Fink B, Matts PJ. J Eur Acad Dermatol Venereol. 2008 Apr;22(4):493-498. Epub 2007 Dec 13)," Dr. Bertin says.

However, Mr. Nkengne says, "We were more surprised to see that young and old people do not preferentially look at the same attributes."

Psychological literature suggests that face recognition and memorization are learning processes, and that people perform these tasks more accurately within their own age group, he says.

"This may explain why older people focus on the lips and eye openings, since they are facing major changes in these areas with age," Mr. Nkengne says.

Conversely, younger people are more concerned with changes that appear at earlier life stages, even if the changes - such as tone unevenness and nasolabial folds - are unrelated to aging, he says.

The study's findings could allow dermatologists to simplify cosmetic procedures, Dr. Bertin says.