Study: How to Look Trustworthy

Princeton researchers find a U-shaped mouth and surprised eyes are judged trustworthy.

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Two researchers at Princeton University have discovered they can tweak certain features of a computerized human face to maximize its appearance of trustworthiness or untrustworthiness.

The researchers say their work may have implications for people in jobs like sales—where facial expressions would have a considerable effect on customer interaction and business overall. Humans "make split-second judgments on faces on two major measures—whether the person should be approached or avoided and whether the person is weak or strong," according to the report on Princeton's website.

From the report:

A trustworthy face, at its most extreme, has a U-shaped mouth and eyes that form an almost surprised look. An untrustworthy face, at its most extreme, is an angry one with the edges of the mouth curled down and eyebrows pointing down at the center. The least dominant face possible is one resembling a baby's with a larger distance between the eyes and the eyebrows than other faces. A threatening face can be obtained by averaging an untrustworthy and a dominant face.

This should probably not be interpreted as a report on physical appearance—rather on outward expression. Facial expressions tend to be outward displays of inward feelings, and sometimes we convey emotions we're not aware of. I fear, however, the manipulation of a study like this. After all, we don't want to arm untrustworthy people with the details on how to charm their way past our brains' innate evaluative mechanisms.