On Nov. 27, 2008, Indian police interrogators came face to face with the only gunman captured alive in last year's bloody Mumbai terror attacks. They were surprised by what they saw. Ajmal Kasab, who had murdered dozens in the city's main railway station, stood barely 5 feet tall, with bright eyes and apple cheeks. His boyish looks earned him a nickname among Indians—"the baby-faced killer"—and further spooked a rattled public. "Who or what is he? Dangerous fanatic or exploited innocent?"wondered a horrified columnist in the Times of India. No one, it seems, had expected the face of terror to look so sweet.
The notion that a man's mug reveals his character is an age-old bias. Since Aristotle, people have thought it possible to infer personality traits from the face and body, an art known as physiognomy. The practice grew popular in the years after the American Revolution, when a Swiss enthusiast published a series of illustrated pocket guides to help readers interpret faces on the go. Soon, it was plain to everyone that a man's greatness was prefigured in his face. (George Washington's big schnoz, for example, signaled strength and foresight.) Over the next 150 years, a gang of enterprising physiognomists set about using the new "science" to identify society's bad apples, too.
In the late 19th century, the Italian criminologist Cesare Lombroso ran autopsies on convicts and cataloged features that might identify "born criminals," such as jug ears and overdeveloped canines. In the 1930s, Harvard's Earnest Hooton examined 14,000 prisoners and observed that first-degree murderers tended to have straight hair, while the hair of second-degree murderers was unusually golden. A few years later, Columbia psychologist William Sheldon studied delinquent youth and invented a human taxonomy consisting of three types—ectomorphs (thin-faced, skinny, brainy), mesomorphs (broad-faced, muscular, aggressive), and endomorphs (round-faced, fat, sociable). He further divided these groups into 88 subtypes named after animals, such as the Herons (very often Phi Beta Kappas, he wrote) and the Foxes and Coyotes (Jesus Christ's type, per Sheldon). Overall, he concluded that the meaty-faced mesomorphs were most prone to criminality.
Much of this work fell apart under scrutiny. Lombroso's statistical methods stunk. Hooton chucked data that didn't fit his hypothesis. Sheldon had not examined very many criminal delinquents, and no one much understood how he distinguished a Great Cat (such as King Arthur) from a Great Saber-tooth Bobcat (e.g., Bronko Nagurski) in the first place. In the wake of the Nazi death camps, theories of "criminal anthropology" fell from favor, and researchers emphasized social explanations for behavior.
But today, physiognomy is making a comeback. In the last decade, breakthroughs in 3-D modeling and animation software have opened up the field. At the same time, ideas from genetics and evolutionary psychology are reanimating old debates about biological determinism, race and gender differences, and why humans possess the faces and bodies that we do.
The new research suggests we are more skilled at "reading faces" than we knew. People are surprisingly adept at assessing sexual orientation from headshots. Five-year-olds can predict election outcomes based on photos of the candidates. We can even guess whether a face belongs to a Democrat or a Republican at a rate better than chance, according to a forthcoming study out of Princeton.
Now some of the "new physiognomists" are resurrecting an old claim: that you can gauge a man's penchant for aggression by the cut of his jib. Last fall University of California-Santa Barbara psychologist Aaron Sell reported that college students could accurately estimate the upper body strength of unfamiliar men after viewing their faces alone. (The men's necks were obscured.) The students did equally well with fellow undergraduates and men from South American indigenous groups—all of whom had had their strength measured using gym equipment. Interestingly, the toughest-looking undergrads also reported getting in the most fights. Another study by Sell suggests that such formidable men are more prone to use violence—or advocate military action—to resolve conflicts.
Many animals employ similar systems. Male orangutans grow fatty cheek pads that reflect group status. Lions with long, dark manes tend to rule the pride. From an evolutionary perspective, these advertisements may be a convenient way of saying, "Hey bro—btw, I can kick your ass" without having to go through the risk of combat.