Red in the face: One of the computer manipulated faces used for the study. It looks healthy because it appears to be flushed with oxygenated blood, making it bright and rosy.
Credit: Perceptionlab.com
SYDNEY: People use facial colour as an indicator of wellbeing, associating a rosy complexion with good health, a new study reports.
Though the idea has long been suspected, the research, reported in the journal PloS One, is the first to show that healthy faces appear redder due to higher levels of blood and oxygen in the skin and that this may be an important factor in selecting a mate.
“Since health and attractiveness are closely related, this may have implications for evolution,” said Ian Stephen, study co-author and psychologist at the University of St Andrews in Scotland.
Blood benefits
The researchers first measured how skin colour varies with the amount of oxygen and blood in the skin. More blood turns a face red, but the shade depends on the blood’s oxygen content. Oxygen-rich blood turns the face a bright red, while deoxygenated blood results in a blue-red.
The researchers then presented 59 study participants with photographs of 51 different faces. Using computer graphics, participants were told to manipulate the faces’ colours to make them appear as healthy as possible.
The participants choose to add red pigment to most faces – a change that would occur with the addition of oxygen-rich blood. Their colour adjustments suggested that people view oxygen-rich blood as more healthy than deoxygenated.
“It was remarkable that observers are so sensitive to this difference and that there should be such a strong preference for oxygen,” Stephen said.
Link to attractiveness
There is such a thing as too much red, however. The redder a face was to begin with, the less red pigment participants chose to add. “This actually hints at an optimum level of facial redness,” commented Kevin Brooks, a psychologist with Macquarie University in Sydney. “Just as a face that is not red enough looks unhealthy, one that is too red also looks unhealthy.”
Stephen said these results make sense because blood levels actually do correlate with health. People in good shape or with high levels of sex hormones have more blood in the skin than smokers or the elderly. In addition, the physically fit have more oxygen in their blood.
The good news is that “you may be able to improve your complexion to look healthier and more attractive by taking some simple steps like exercising more or quitting smoking,” Stephens said.
Brooks, who was not involved with the research, said the study was well-designed and offered possible applications for its findings. “It would not be surprising if advertising agencies promoting health products were to use spokespeople with redder than average skin,” Brooks said.
Leigh Simmons, an evolutionary biologist with the University of Western Australia in Perth, said a healthy-looking face could provide an advantage in finding a mate because a healthy partner could offer benefits such as avoiding infections.
He added that other facial features, including symmetry and 'averageness', have already been linked to attractiveness. To add facial colour to that list, Simmons said, “the next step will be to ask whether optimal levels of facial redness… influence reproductive success.”
