Luminosity in the eyes of the beholder
Caren B. Les
The human eye takes significant cues from visual contrast within a woman’s facial skin
to evaluate her age, health and attractiveness according to a study by researchers
at Ludwig Boltzman Institute of Urban Ethology in Vienna, Austria, and in the department
of sociobiology/anthropology at University of Göttingen in Germany. Using
digital imaging and morphing software technologies, they determined that contrast
produced by skin discoloration and uneven tone, independent of lines, wrinkles or
facial shape, can make a woman appear older — or even younger — than
her chronological age. Cosmetic treatment for the related skin conditions could
be developed as a result of the study.
In collaboration with Paul Matts of Procter &
Gamble Co., the study was made to determine the extent to which the skin’s
overall homogeneity and color saturation function as an age cue. Behavioral scientists
have paid little attention to skin tone and luminosity, which may affect how a woman
is perceived, possibly in terms of mate selection.
The quality of a woman’s facial skin tone and the way in which others perceive
it in terms of age and attractiveness were analyzed using 3-D imaging and morphing
software. The examples show images of skin from three females mapped onto universal
head models. The faces represent subjects at the biological ages of 12, 42 and 55
years, from left to right. Their mean perceived ages were 20, 24 and 31 years, respectively.
Photos courtesy of P&G Beauty.
Led by Karl Grammer and Bernhard Fink,
the group used a Fuji S2 Pro 6.2-megapixel digital camera to take standardized images
of 169 Caucasian women ranging in age from 10 to 70 years. Each woman’s face
was photographed frontally, and from the left and right profiles. The high-resolution
images were taken under cross-polarized lighting conditions to eliminate visible
high-frequency/low-amplitude skin surface topography (i.e., ”microtexture”)
in the initial imaging stage.
High-amplitude features that potentially
define age, such as lines and wrinkles around the mouth, nose and eye areas were
then removed using the soft cloning stamp in Adobe Photoshop 7.0. Each face was
fitted onto a template to create 2-D skin color maps incorporating the front and
side views, and the maps were matched with a template grid to fit onto a virtual
standardized 3-D skull, modeled from that of a 20-year-old woman.
Variables such as lighting, camera
angle and such characteristics as eye color, hairstyle and facial shape were eliminated,
leaving skin tone as the only variable.
The 169 standardized faces were blind-rated
by 430 participants on the basis of skin color distribution alone. The raters were
asked to estimate the age of the faces and to answer general questions related to
health, attractiveness and skin characteristics. The faces that were judged to have
the most even skin tone were perceived as being younger and received higher ratings
for health and attractiveness.
The scientists also used the SIAscope
developed by Astron Clinica of Cambridge, UK, to show how light-absorbing molecules
in the skin, called chromophores (which are responsible for visible skin coloration),
are affected by age and UV damage. The noninvasive imaging tool uses a model of
light transport within skin to map the distribution and concentration of melanin
and blood. The scientists plan to use the instrument to further explore the distribution
of chromophores in facial skin as it relates to perceived attractiveness.
Funded by Procter & Gamble, the
project was the subject of a poster presentation at the 2006 Human Behavior and
Evolution Society annual meeting in Philadelphia in June.
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