Voters look for someone who appears both competent and attractive when choosing a president, at least when the candidate is female, finds a new study.

If true, the reportedly astronomical fees spent on vice presidential candidate Sarah Palin's appearance could have been right on the money.

"Campaign managers seem to be ahead of the game in understanding that image really matters," said Joan Y. Chiao, a psychologist at Northwestern University in Illinois. "They know that, contrary to popular notions, people are not necessarily using deliberate and rational strategies in deciding whom to vote for, especially when it comes to women."

Male and female voters

Chiao and her colleagues asked a group of more than 70 undergraduate students, about evenly split between females and males, to judge a series of male and female political candidates on how competent, dominant, attractive and approachable they seemed based on their facial appearances.

Then participants looked at images showing pairs of political candidates and indicated which candidate they would vote for in a hypothetical election for U.S. president.

Overall, participants judged male faces as more competent and dominant than females. And the participants perceived female faces as more attractive and approachable than males.

All participants were most likely to vote for candidates who appeared more competent. However, male candidates who appeared more approachable and female candidates who appeared more attractive were most likely to win votes.

Both male and female participants in the study were most likely to vote for women candidates seen as attractive and competent.

"Even female voters seemed to tap into the cultural expectation that women who are attractive as well as competent are more worthy of high status roles," Chiao said.

The results, detailed online in the Oct. 31 issue of the journal PLoS ONE, diverged for male candidates. Male voters were more likely to vote for a guy only if that candidate appeared competent, while female voters preferred a male candidate who was both competent and approachable.

Voting on the brain

Another recent study also shows that facial looks matter for political candidates. The study, published online this week in the journal Social Cognitive and Affective Neuroscience, suggests that negative views about a person's facial appearance could cost that candidate the election.

The researchers used functional MRI scans to measure brain blood oxygenation of participants as they made decisions about pairs of political candidates based solely on the candidates' photos. The candidates had run in elections in 2002, 2004 or 2006. In some cases, the participants had to cast a hypothetical vote and in others they made character judgments about each candidate, including which of the two looked more competent to hold a congressional office or looked more physically threatening.

When participants viewed photos of politicians who lost elections, in the lab and in the actual elections, brain areas associated with processing emotions showed activity. The results suggest negative evaluations of a candidate based on appearance affect real election outcomes, said lead researcher Michael Spezio, a psychologist at Scripps College and a visiting associate at Caltech.

The researchers stress that the brain effects seen, while statistically significant, were small. In addition, the results likely only apply to voters who know very little about the political candidates, and in general, appearance is just one piece of the political puzzle.

"We are not claiming that how the candidates look is all there is to the story of how voters make up their minds — or that this is even the biggest part of the story," said Ralph Adolphs, a professor of psychology and neuroscience at Caltech. "However, we do think it has some effect — and, moreover, that this effect may be largest when voters know little else about a candidate."

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