As Psychologists we like to think that we ‘never judge a book by its cover’, however when it comes to human faces there are many assumptions that we do make. Professor Perrett argues that many of those assumptions are supported by evidence; faces do give us important clues as to personality, trustworthiness and health.

Professor Perrett gave his presentation in the impressive surroundings of The Dynamic Earth Centre in Edinburgh. Trustworthiness is something we tend to judge by behaviour rather than appearance, and indeed, early research by Michael Stirrat found that evidence gathered from static faces was unreliable. Further research, using economic games based on co-operation or exploitation, uncovered that slim faces were likely to be judged more trustworthy than more robust, wider faces. This correlates with evidence from ice hockey, that players with wide faces tended to spend more time in the penalty box. On the whole, it is male faces that are wider and this is linked to testosterone. Professor Perrett argued that human faces have evolved to become narrower as co-operation became more important for survival.

Research by Stephen, Coetzee and Law Smith found that perception of health is linked to colour cues in the skin. Of course, we know this already, all our grandmothers have told us we looked pale and therefore must be ill at some time or other. Women, use make-up to mimic good health; rouge on their cheeks and lipstick to mimic sexual attraction and arousal. Human skin colour is obviously linked to ethnicity and race, but there are some constants. Faces reflect health through skin tone. Some of the factors of apparent health are HLA immune genes, reproductive genes, body fat and lifestyle (sleep, exercise, diet). To investigate this experimentally, composite faces were made by blending several images to create average faces. These were then colour manipulated.  Participants were asked to change the colour of the faces, using the computer mouse to make them look healthier. In the UK, South Africa and Australia, participants added more red. Rankin, Coetzee even found this in African faces. When participants were asked to manipulate the blue/yellow axis, they added more yellow. So red/yellow faces are judged healthiest.

There are three factors that effect skin pigment; these are blood, melanin and carotenoids. Oxygenated blood is redder and this makes skin look healthier. Oxygenation of blood is improved by fitness training and influenced by reproductive hormones.  Therefore exercise can improve the appearance of the skin, making an individual both look and actually be healthier. Tanned faces reflect the presence of melanin, people do tend to look healthier with a bit of a tan, however, remember your sun screen! Carotenoids are found in food, especially fruit and vegetables. It turns out that eating too many carrots really can turn you orange! Carotenoids are yellow-red pigments that aid the immune system, in some animals they are used in ornamentation for sexual selection (feather colour etc.) When participants were fed ß-carotene over an 8 week period their skin tone did change. So eating more fruit and vegetables can not only make us healthier, but change our appearance for the better too. Skin really does reflect diet.

Of course, fashion and ethnicity are variables in preferences for faces, but the findings suggest that judgements of health remain constant. Perhaps the most important implication of this research is that it could be used to motivate people to live a healthier lifestyle. Telling young people that eating their five-a-day of fruit and vegetables will make them live longer, be less likely to contract certain illnesses in the future etc., is not effective, however, saying it will improve your physical appearance and therefore make you more attractive to perspective partners could well be.

Deb Gajic
Chair of the ATP

Further references: -
www.perceptionlab.com
www.faceresearch.org