But a "trustworthy face" can be faked.
Judging character or personality traits in a face is an idea that never seems to go away: In Victorian literature, men will have "cruel mouths"; in New York magazine, Kristen Stewart was diagnosed with "bitchy resting face." Those unfairly topped with devious faces can take some encouragement from new research just published in the journal Personality and Social Psychology Bulletin, which indicates that, while some personality traits are etched into the shape of the face itself, some positive traits can be brought out with a simple change of expression.
Whether or not our personalities actually match our faces, these judgments, which we make quickly and unconsciously, exert real sway in the world. Studies have shown that people are less likely to find baby-faced men guilty for crimes but more likely to find them guilty of negligence. People also will vote for politicians who have "competent-looking faces," and pick financial advisors who have "trustworthy faces." Even if you couldn't draw or imagine a "competent" or "trustworthy" face right now, the research indicates that you'd know it if you saw it.
Researchers paid people via Amazon's Mechanical Turk to rate how "trustworthy" or "untrustworthy" they thought people in pictures were, and found that people strongly agreed on which pictures had trustworthy looking people in them. However, this perceived trustworthiness varied among different pictures of the same person, so the researchers were able to use different pictures to test the same face with subtly altered facial features and expressions. They even digitally generated faces and changed specific features to fine tune it. They discovered that the difference between someone seeming trustworthy or not is pretty simple.
"We found that a face's subtle resemblance to an angry expression (with downturned brows) leads an individual to more readily be perceived as untrustworthy. A face's subtle resemblance to a happy expression (with upturned brows and upward curving mouth) leads an individual to more readily be perceived as trustworthy," Jonathan Freeman, one of the study's co-authors, told me in an email.
Freeman runs the Social Cognitive & Neural Sciences Lab at New York University, and I asked him if there was any research that looked into why having a cheerful resting face makes someone look more trustworthy.
"In our prior brain-imaging research, we have shown that the brain is highly sensitive to trustworthiness cues and can process it without conscious awareness," he said. "We believe this is because the brain is strongly attuned to emotional expressions, and when our faces subtly resemble one, a number of inferences are generated spontaneously, including trustworthiness."
Somewhat ironically, the fact that we assess trustworthiness partly on facial expressions means it can be faked. That's not the case for a "competent face" however. The researchers found that perceptions of competence are based on "facial width-to-height ratio"—basically, the wider the better.
"Unlike trustworthiness, which is conveyed largely by the face's dynamic musculature, [perceived competence] is based in the face's skeletal structure which cannot be changed for the most part," Freeman said. Prior work has linked a wider face to higher amounts of testosterone, as well as more aggressive behavior in men.
"It is possible that by observing wider-faced men tending to be more aggressive, the association is implicitly learned between facial width and more general forms of ability, but this is a question that would need to be directly tested in future research," Freeman said.
Of course, in the real world, we make snap judgments based on many traits, like body language, clothing, posture, not just faces. But as the presidential election cycle begins anew in America, it's worth taking a minute to ask yourself, "am I voting for the policies I want, or just a great facial width-to-height ratio?"