People form judgments about a stranger’s trustworthiness and competence after seeing their face for just one-tenth of a second — and Princeton researchers found that more viewing time did surprisingly little to change the impression, mostly making people more confident in it.

People form judgments about a stranger’s trustworthiness and competence after seeing their face for just one-tenth of a second — and Princeton researchers found that more viewing time did surprisingly little to change the impression, mostly making people more confident in it.

One-tenth of a second is shorter than a blink. In a series of Princeton experiments, it was still enough time for people to decide whether an unfamiliar face looked trustworthy, competent, likeable, attractive or aggressive. Their 100-millisecond judgments closely resembled the ratings made by another group who could inspect the same faces without a time limit. Giving viewers half a second or a full second did not significantly improve that agre…