What makes a pretty face?

Animals — including people — are innately drawn to beauty, which may be defined by symmetry or health
Dec 2, 2016 — 1:20 pm EST
5 pretty faces

They say that beauty is in the eye of the beholder. But what aspects make someone gorgeous? Science has turned up some answers.


We all know we shouldn’t judge people based on their looks. Beauty is only skin-deep, as the saying goes. Moreover, someone’s appearance doesn’t tell us anything about how kind they are. Or how dependable. Or anything else about their personality.

But it’s hard to ignore the way a person looks. Something about attractive people makes us want to watch them. We can’t take our eyes off a good-looking actor, actress or model. As such, beauty has power over us. But what is beauty?

There is no simple answer. Researchers have, however, begun probing how beauty affects the behavior of humans and other animals. Through this work, especially, they have discovered some of the features that make an individual attractive to others.

Scientists are also learning that there may be a practical side to our obsession with beauty. A pretty face may belong to a healthier person. Or it may simply be easier for our brains to process.

All about averages

Looking at a set of photos, it’s easy to say which faces we find attractive. Different people will usually agree on which faces those are. But few can say precisely why those faces seem so beautiful.

A peacock displays for females by fanning his tail and doing a shivery dance.
Paul Dinning/YouTube

Adeline Loyau is a behavioral ecologist who has seen similar things in peacocks. She works at the Helmholtz Center for Environmental Research in Leipzig, Germany. Back when she was working for a government research agency in France, she began studying the birds’ eyespots. These are the vivid circles at the ends of their tail feathers. She knew peahens prefer males with more eyespots. They also prefer males that show off their tails more. Her work has now shown that healthier peacocks have more eyespots in their tails. These birds also splay their flashy tails more frequently to the females.

EEG setup
These EEG sensors record brain activity. The Langlois lab uses EEG set-ups to learn how our brains process different faces.
Petter Kallioinen/Wikimedia

The researchers then searched the EEGs for patterns of electrical activity. Those patterns offered signs of what the brain was doing. The students’ brains processed human faces faster than chimpanzee faces, the EEGs showed. That makes sense, the researchers now say, because people are more familiar with human faces. They look normal to us, so we don’t have to spend much time thinking about them.

The team also found that brains processed very attractive faces faster than unattractive ones. And they processed average faces even faster. That means their subjects’ brains found averaged faces easiest to handle. Subjects also rated the averaged faces as most attractive.

The beauty bias

In sum, looks may go far more than skin deep after all. They also can affect how people interact.

Scientists discovered long ago that people show favor to those with a pretty face. Attractive people are more likely to get jobs. They make more money than their less attractive coworkers. We even tend to think attractive people are smarter and friendlier than less attractive people.

Langlois and Angela Griffin (then at the University of Texas) looked for more signs of this “beauty is good” stereotype. And they found it.

The researchers asked people to rate photos of young women’s faces on a five-point scale. The scientists then chose the six photos with the lowest ratings and six with the highest. They chose another six photos that had ratings closest to the average (or mean) score. This set made up their group of “medium”-attractive faces.

Nearly 300 college students were asked to view photos in a random order from the three image sets for 4 seconds each. After each quick view, the students had to answer a question about the person in that last picture. For example, how likely was she to be popular, friendly, helpful, kind or smart?

Both men and women ranked people with unattractive faces as less intelligent, less sociable and less likely to help others. Medium attractive people got similar rankings to highly attractive people for everything except sociability.

Griffin and Langlois then repeated the experiment with children aged seven to nine. They got the same results.

Maybe the stereotype isn’t exactly “beauty is good,” the researchers suggest. Maybe it’s more like “ugly is bad.” They suspect this may be because unattractive faces look less like a “normal” or average face.

It can be hard to stop ourselves from stereotyping others. “Appearance is the first thing we judge people on,” says Little. Still, he says, “Being aware that these biases exist is an important step.” For example, he points out, attractive people aren’t actually smarter. “As we get to know people, physical appearance gets less important,” he says.

Schein agrees. “Knowing that the bias exists, acknowledging that we all carry it with us, and taking steps to consciously decrease your own bias are important,” she says. That can keep us from discriminating against people who are unattractive — or simply uneven.


Power Words

(more about Power Words)

asymmetry      Not symmetrical, such as not the same shape on the left and right sides.

average     (in science) A term for the arithmetic mean, which is the sum of a group of numbers that is then divided by the size of the group.

behavioral ecologist   A scientist who studies how animal behavior relates to where animals live.

bias      The tendency to hold a particular perspective or preference that favors some thing, some group or some choice. Scientists often “blind” subjects to the details of a test (don’t tell them what it is) so that their biases will not affect the results.

discriminate   The detection or recognition of a difference between two or more versions of something. (in social science) To treat groups of people or things differently based a bias about one or more of their attributes (such as race, sex, religion or age).

electrode  (in brain science) Sensors that can pick up electrical activity.

electroencephalography (abbr. EEG)     A technique to detect electrical activity in the brain using electrodes that press against the outside of the head. This technique charts a series of brainwaves. A graph of the measured brainwaves is called an electroencephalogram, which also is abbreviated EEG.

genetic diversity   The range of genes types — and traits — within a population.

immune system    The collection of cells and their responses that help the body fight off infections and deal with foreign substances that may provoke allergies.

innate    Something such as a behavior, attitude or response that is natural, or inborn, and doesn’t have to be learned.

mean    One of several measures of the “average size” of a data set. Most commonly used is the arithmetic mean, obtained by adding the data and dividing by the number of data points.

parasite   An organism that gets benefits from another species, called a host, but doesn’t provide it any benefits. Classic examples of parasites include ticks, fleas and tapeworms.

psychology    (adj. psychological) The study of the human mind, especially in relation to actions and behavior. To do this, some perform research using animals. Scientists and mental-health professionals who work in this field are known as psychologists.

stereotype   A widely held view or explanation for something, which often may be wrong because it has been overly simplified.

subtly      An adverb to describe something that may be important, but can be hard to see or describe. For instance, the first cellular changes that signal the start of a cancer may be subtly visible  — as in small and hard to distinguish from nearby healthy tissues.

symmetry   In geometry, the property of being indistinguishable from a shifted, rotated or reflected image of the same object. For example, the letter X looks the same whether reflected in a mirror or turned upside down — two different kinds of symmetry.

ultraviolet    A portion of the light spectrum that is close to violet but invisible to the human eye.


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Journal: K.F. Ryan & I. Gauthier. Gender differences in recognition of toy faces suggest a contribution of experience. Vision Research. Vol. 129, December 2016, p. 69. doi: 10.1016/j.visres.2016.10.003.

Journal: L.T. Trujillo et al. Beauty is in the ease of the beholding: A neurophysiological test of the averageness theory of facial attractiveness. Cognitive, Affective, & Behavioral Neuroscience. Vol. 14, published online December 11, 2013, p. 1061. doi: 10.3758/s13415-013-0230-2.

Journal: M.R. Morris et al. Fluctuating asymmetry indicates the optimization of growth rate over developmental stability. Functional Ecology. Vol. 26, published online March 27, 2012, p. 723. doi: 10.1111/j.1365-2435.2012.01983.x.

Journal: A.C. Little et al. Facial attractiveness: evolutionary based research. Philosophical Transactions of the Royal Society B. Vol. 366, published online May 2, 2011, p. 1638. doi: 10.1098/rstb.2010.0404.

Journal: P.M Pallett et al. New “golden” ratios for facial beauty. Vision Research. Vol. 50, published online November 6, 2009, p. 149. doi: 10.1016/j.visres.2009.11.003.

Journal: A.C. Little et al. Symmetry is related to sexual dimorphism in faces: Data across culture and species. PLOS One. Vol. 3, May 7, 2008, p. e2016. doi: 10.1271/journal.pone.0002106.

Journal: C.L. Apicella et al. Facial averageness and attractiveness in an isolated population of hunter-gatherers. Perception. Vol. 36, published online January 31, 2007, p. 1813. doi: 10.1068/p5601.

Journal: A.M. Griffin and J.H. Langlois. Stereotype directionality and attractiveness stereotyping: Is beauty good or is ugly bad? Social Cognition. Vol. 24, October 1, 2006, p. 187. doi: 10.1521/soco.2006.24.2.187.

Journal: S.M. Doucet and R. Montgomerie. Multiple sexual ornaments in satin bowerbirds: Ultraviolet plumage and bowers signal different aspects of male quality. Behavioral Ecology. Vol. 14, September 2002, p. 503. doi: 10.1093/beheco/arg035.

Book: R.A. Hoss and J.H. Langlois. Infants prefer attractive faces. A chapter in O. Pascalis & A. Slater (eds.), The Development of Face Processing in Infancy and Early Childhood: Current Perspectives (p. 27-38). 2003.  New York: Nova Science Publishers.

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