We really do judge a book by its cover—and, it seems, the competence of politicians by their faces. What's more, adults and kids see the same competence—or, as the case may be, ineptitude—in a person's visage, which helps explain why children can accurately predict presidential elections, according to new research published today in Science.

Swiss adults unfamiliar with French politics were shown 57 pairs of photos of opponents from an old French parliamentary election and asked to pick which ones looked most competent. In a separate experiment, Swiss kids ages 5 to 13 played a computer game that enacted Odysseus' trip from Troy to Ithaca. Then, using the same pairs of photos, researchers asked the kids which candidate they'd choose to captain their ship. In both experiments, the adults and children tended to pick the winners of the election.

"Adults and children infer competence in precisely the same way, whether that [person] is six or seven — or 67. That is the shocking finding here," study co-author John Antonakis, a professor of organizational behavior at the University of Lausanne, tells ScientificAmerican.com. "This stereotype is already formed in young childhood, which leads us to suggest this mechanism is innate or develops very, very rapidly at a young age."

The study didn’t examine what, exactly, led people to see competence in one face more than another. All the photos were black and white and were of same-sex, same-race pairs of candidates wearing about the same expression. The findings build on research published in Science four years ago showing that Americans who judged competence based on facial appearance predicted the true outcomes of U.S. congressional elections at rates better than chance. (Kids' publisher Scholastic, which has held student presidential votes since 1940, says that their results have been the same as the general election outcome all but twice, in 1948 and 1960. In 2000, the kids voted the same as the electoral college—and so, for George W. Bush—but not the popular vote, which went to Al Gore.)

None of this is to say that the truism "don't judge a book by its cover" is obsolete. While our judgments about competence tend to translate into election results, they're not so great at predicting true leadership. What does correlate with a president's performance is his estimated IQ—not his face, according to a 2006 study in Political Psychology.

"If people were good at inferring how smart people are from a distance," Antonakis says,  "all the politicians we elected would be very clever."

Image courtesy of Science/AAAS