Number of words: 393

Ambady had originally wanted to study what makes teachers effective. She suspected that nonverbal cues — body language and such — were important. To test this, she used some videotapes that had been made of a group of Harvard teaching fellows. She planned to show silent video clips to a group of people and have them rate the teachers for effectiveness.

Ambady wanted to use one-minute clips of each teacher. Unfortunately, the tapes hadn’t been shot with this end in mind. They showed the teachers interacting with stu-dents. That was a problem, because having students visible in the clips might unconsciously affect the raters’ opinions of the teachers. Ambady went to her adviser and said it wasn’t going to work. Then Ambady looked at the tapes again and decided she could get ten-second clips of teachers in which no students were visible. She did the study with those ten-second clips. Based on just ten seconds, the raters judged the teachers on a fifteen-item list of qualities.

Okay, if you have to judge someone from a ten-second video clip, you can. You probably wouldn’t expect sueh a judgment to be worth anything. Ambady repeated the experiment with five-second clips of the same teachers. Another group of raters judged them. Their assessments were, allowing for statistical error, identical to the ratings of the people who saw the ten-second clips. Ambady then had another group view two-second clips of the same teachers. Again, the ratings were essentially the same.

The shocker was this: Ambady compared the video-clip ratings to ratings made by the students of the same teachers after a semester of classes. The students knew the professors much better than anyone possibly could from a silent video clip. No matter — the students’ ratings were in close agreement with those of the people who saw only the videos. Complete strangers’ opinions of a teacher, based on a silent two-second video, were nearly the same as those of students who had sat through a semester of classes.

It looks like people make a snap judgment of a person within two seconds of meeting him or her — a judgment not based on anything the person says. Only rarely does anything that happens after the first two seconds cause the judger to revise that first impression significantly.

Excerpted from page numbers15-16 of ‘How Would You Move Mount Fuji?’ by William Poundstone.