Janine Willis and Alexander Todorov asked university students to rate the attractiveness, likeability, competence, trustworthiness, and aggressiveness of actors’ faces after looking at their photos for just 100ms. The ratings they gave the faces correlated strongly with ratings given by other students who were allowed as long as they wanted to rate the faces. The strongest correlation was for trustworthiness. “Maybe as soon as a face is there, you know whether to trust it”, the researchers surmised.
As the time the students were given was increased up to half a second, or to a whole second, their ratings continued to correlate just as strongly with the ratings given by the students who were allowed as long as they wanted to rate the faces. However, with more time, the students’ ratings became slightly more negative and their confidence in their judgments increased.
“These findings suggest that minimal exposure to faces is sufficient for people to form trait impressions, and that additional exposure time can simply boost confidence in these impressions. That is, additional encounters with a person may only serve to justify quick, initial, on-line judgments”, the researchers said.
Willis, J. & Todorov, A. (2006). First impressions. Making up your mind after a 100-Ms exposure to a face. Psychological Science, 17, 592-598.