WASHINGTON - Women had better appear attractive as well as competent if they want to be elected to political office, according to research published on Thursday.
The reason may be the same as people preferring attractive mates -- good looks tend to signal overall biological fitness, said psychologist Joan Chiao of Northwestern University in Illinois.
"People have found that aspects of the face predict, for example, whether or not somebody is at height of their estrus cycle" and thus fertile, Chiao said in a telephone interview. "Aspects of male faces seem to predict levels of testosterone."
In other words, humans find certain features attractive not because there is some "true" measure of beauty but because they signal success.
The study relied on 73 college students but the researchers said the findings fit in not only with conventional wisdom but with other research.
Despite inroads made by the likes of New York Sen. Hillary Clinton and Republican vice presidential candidate and Alaska Gov. Sarah Palin, men continue to hold an advantage overall.
"All voters perceived male politicians as significantly more competent compared to female politicians," Chiao and colleagues wrote in their report, published in the Public Library of Science journal PLoS ONE.
Chiao's team showed photographs of candidates for Congress in 2006 to their volunteers and asked questions such as whether they would choose one over the other for president.
Everyone had to seem competent to get a vote. But while men needed to appear approachable to get an edge, women had to be good-looking, the researchers found.
Studies have shown that this effect tends to go away when more women run for high office -- as has happened in India, for example, Chiao said.
"Voters may be able to learn to reduce their reliance on these cognitive short-cuts," she said.
Although Chiao's team only used photographs to ask about the hypothetical voting situation, they found that their "election" mirrored the real 2006 results.
"Candidates who were more likely to get votes in this experiment were more likely to get votes in the real election," Chiao said.
Perhaps once people get into the voting booth, they rely on their guts more than any careful thinking, she said.
"Contrary to the notion that people use deliberate, rational strategies when deciding whom to vote for in major political elections, research indicates that people use shallow decision heuristics, such as impressions of competence solely from a candidate's facial appearance, when deciding whom to vote for," the researchers wrote.