A human baby is not born being able to recognize faces, but the skill is picked up very quickly; after two months, an infant knows faces are important, and shortly thereafter mom and dad can be identified visually. Before a baby is a year old, emotions like love, anger or excitement are understood via facial cues. It doesn't end there. Though there are those who lack the ability to discern differences in faces (called prosopagnosia), recognition and understanding the meaning behind expressions is important to human cultural evolution and communication and develops throughout our lives. In David Perrett's book, "In Your Face: The New Science of Human Attraction," he puts together his years of research to open up the sometimes mysterious world of what our faces reveal to those around us — and what determinations, both conscious and subconscious, we make about others. 


If you'd like an overview of Perrett's work before picking up the book, check out his Perception Lab. Run from the University of St. Andrews in Scotland's psychology department, the site hosts demos that are described in the book, from transforming a picture of your face to understand cues on your own mug, to participating in ongoing research on face cues.


 MNN: What can you really tell just from looking at someone's face?

Perrett: [Faces] allow us to isolate cues that tell us about behaviour: whether or not someone can be trusted or whether or not they are open or averse to "one night stands." Other cues we find tell us about levels of sex hormones, and health: the likelihood of contracting flu; how many fruit and vegetables portions they eat.


Are you one of the "naturals" who is great at reading faces without training? Do you have any insights into what traits make someone great or terrible at reading faces? (I know in one section of the book you mention that people who are more judgmental and cool tend to be better at this than warm, optimistic ones. Any more about that?)

What makes people different in the way they read faces is incredibly important. Each domain of face reading is different. If we are not very powerful then we may become more tuned into face cues to suggest cooperation. We find that socially anxious individuals are more attentive and needy of positive expressions in others. Those in hostile social environments can become biased or perhaps more sensitive to negative expressions.


It seems that people are simultaneously great in some cases, and terrible in others at reading faces. How is it that some of us only have moderate talent at reading others' faces?

I think the average person has amazing face reading talents. In all the face tests I illustrate in the book or run online at Perceptionlab.com, there is a consensus on the answers. Your readers can try out their own face reading skills. That said, the cues in faces are subtle. In social situations we have to second guess what others will do, and how relationships will turn out. Our hunches are right the majority of times, but we should not expect 100 percent success.


In Chapter 9, you reference how Lavater, a Swiss pastor, attempted to ascribe particular personality traits to facial features in his book "Essays on Physiognomy." The connection between a person's basic features and their actions was discredited hundreds of years ago. Yet we still tend to judge people based on their faces. Why do you think this is?

The short answer is that there are face cues to personality. Physiognomy was just bad science. Modern medicine works even though many old practices from Lavater’s time are discredited. Bloodletting was a medical panacea for centuries but is now recognized as useless except for very specific conditions.


Does the ubiquity of plastic surgery affect the outcome of your work? Or are eyelifts, nose jobs and and Botoxed areas insignificant in the overall reading of a face?

There is a huge industry selling us beauty. Surgery seems misplaced. What my research shows is that there are far more powerful ways of improving our allure. Face structure may contribute to first impressions but being attentive to a person; being positive, expressive and reactive counts for far more. Indeed it is a paradox that Botox paralyzes the muscles, preventing smiles.


Health has the most dramatic effect on attraction — our research shows that we recognize health accurately from face structure and facial skin tone. Everyone can improve both their health and attractiveness quite easily through appropriate exercise and a sensible diet.


You write quite a bit about what attracts us to our lovers/partners, getting into the nitty gritty about the complex interactions between attractiveness based on health, hormone levels, family influences and personality too (which is oft-ignored in pop science looks at studies in this category), and point out that for survival of the species, initial attraction is important, but so is longevity of relationships for community cohesion and stability for children. Why do you think the "falling in love" aspect of your work is so much more commonly written about (and studied, it seems)? And what prompted you to look deeper into what about our faces makes us stay with someone over time?

Being in love is dramatic and powerful; no wonder it is the commonest subject of poems and books. Keeping a partnership and bringing up kids is the point of it all. I begun to look deeper into facial signals of quality as a parent and partner because participants were telling me that faces I had masculinized looked "cold." The emphasis of my book is how personal attraction is. Sure there are global rules of what contributes to beauty, but what is more interesting is explaining why we don’t all fall for the same person. As you note, our different tastes in personality and our life experiences ensure unique desires and attractions. I spend time considering why personality shines through in facial appearance, and how our looks shape the way others behave to us.


In her book "The Substance of Style," author Virginia Postrel writes, "An hour watching television, flipping through magazines, or driving down billboard-lined streets exposes us to more beautiful people, more different types, than most of our forbears would have seen in a lifetime." Do you think that modern society, which exposes us to more attractive (and varied) faces, is ultimately confusing to us, having evolved in small communities with a limited number of mates to choose from? Or do you think we can easily adapt our perceptions to a larger and more varied pool of faces?

Undoubtedly our experience biases the way we see faces. I explain the influence that parents have, right from the first moments of life, on faces that draw our attention, and later in life how we take short cuts, copying peers in who they fancy. Our modern life is more complex and populated than it was several thousand years ago, nonetheless the same rules apply. Ultimately, what counts most is our experience with boyfriends or girlfriends; this trains us to love (or loathe) particular faces.


Have you seen the Fox TV show "Lie to Me"? It is about a facial recognition expert (played by Tim Roth) who solves crimes by "reading" people. I was wondering if you think Hollywood has done an accurate job portraying your research.

I haven’t seen the series. There are lots of different situations where people are not forthcoming with the truth or wilfully exploit others. In each situation there will be a variety of facial giveaways, many still to be discovered. Science translates quickly into TV. I’ve seen our findings on changes in sexual attraction used in TV within six months. "Lie to Me" has a perfect setting for drama involving social dilemmas, experts. But the camera, the actors and the script will not be telling the whole truth!


Thanks to your book, we now know so much about faces and what they say about us (or not). What are the next big, interesting questions you are tackling? 

Right now I work on cues to health and personality. We recognize in others charisma, leadership, cooperativeness. How do we do that? Faces seem to act as a health certificate — how so? Some cues are obvious like a cheery smile, but are there other symptoms in stature, posture or skin appearance? At a practical level I am interested to see whether we can get people to improve their health. I think people may be motivated to do this by wanting to look more attractive.