Say what you will about Sarah Palin’s experience, competence and views on (to pick just two of Lab Notes' favorites) creationism and climate change, give her this: she's got that whole beauty queen thing going for her. Roll your eyes if you must, but in a finding that will further depress anyone who still thinks that voters are rational scientists, for female pols, looks really, really matter.

According to a new study, to win the votes of men as well as women, female political candidates need to be seen as attractive. “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,” said psychology researcher Joan Y. Chiao of Northwestern University, who led the study, which is being published tomorrow in the online journal PLoS One.

The research is part of the growing recognition that voting decisions do not reflect logical, rational analyses of candidates’ positions and records, but an emotional, even visceral reaction. Or as Chiao and her colleagues put it, “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.”

For their study, the scientists had 73 volunteers (college students) score 106 male and female candidates in the 2006 congressional elections on a 7-point scale on several traits: competence, dominance, attractiveness and approachability, all based on their looks (face only). Then the volunteers saw the same candidates, in pairs, and were asked to say which one they would vote for for president. (The scientists made sure than the volunteers did not recognize any of the candidates; no Nancy Pelosi pictures, for instance.)

All of the volunteer voters were more likely to vote for candidates who looked more competent. (I guess that's good news, except that the assessment of "competence' was based purely on looks.) But more-attractive female candidates got more votes than homelier ones, especially from men, and the difference in vote-getting ability between attractive and less-attractive candidates was greater for female candidates than for males. Perhaps it is no coincidence that more men than women have favorable views of Palin.

What’s “attractive”? For men, faces with “mature” features (thick eyebrows, square face, large chins), which are associated with strength and assertiveness, traits that society expects from men. For women, immature features (thin eyebrows, round face, small chins), which are considered signs of less physical strength and assertiveness and of a more nurturing and sensitive nature, traits that society expects from women.

The scientists put it this way in their conclusion: “Good looks was almost all that mattered in predicting men’s votes for female candidates. And, true to prevailing stereotypes, competence was almost all that mattered in predicting men’s votes for male candidates.” Chiao gives campaign managers credit for “understanding that image really matters,” she said. “They know that, contrary to popular notions, people are not necessarily using deliberate and rational strategies in deciding who to vote for, especially when it comes to women.”

Other research has also found that appearance plays a role in how voters judge candidates. A 2005 study found that people’s impressions of the competence of a candidate based solely on their facial appearance predict the outcomes of recent U.S. congressional elections, while a 2007 study found that differences in facial shape predict which candidate will win an election.

Oh, and if this seems like some empty academic exercise, consider this. In the actual 2006 congressional races, candidates perceived as more attractive by men in this lab experiment were more likely to win. So let’s forget all this high-minded talk about how undecideds will break and how Reagan Democrats will vote, and focus on the question that can really predict next Tuesday’s outcome: who’s cuter, McCain or Obama?