Alexander Todorov, an assistant professor of psychology and public affairs at Princeton University, and Nikolaas Oosterhof, a research specialist, have built a computer program that will help scientists better analyze why certain human faces evoke trust while others elicit fear. In past studies, the researchers learned that people make instant judgments about a person's face and that these judgments then affect how they feel about the person. "Humans seem to be wired to look to faces to understand the person's intentions," Todorov said in a press release. "People are always asking themselves, 'Does this person have good or bad intentions?'"
Recently, the researchers discovered that these split-second decisions are based on two things: whether a person should be approached or avoided and whether a person seems weak or strong. So they decided to try to define just which facial characteristics—namely, what eye, nose, and mouth placements—make a face seem trustworthy or dominant. The most trustworthy face, the researchers found, has a U-shaped mouth and eyes that look almost surprised, with upturned eyebrows. The most untrustworthy face has a mouth curled down at the edges and eyebrows that also point downward—basically, an angry face. The least dominant faces, they say, have a larger distance between the eyes and eyebrows than other faces do. While you can't control your facial features, the study shows that expressions do matter, which could be an extra important lesson for people whose jobs require a high-level of public interaction (think teachers, politicians, and religious leaders).
The study appears in the Proceedings of the National Academy of Sciences online. —Heather Wax