I've heard of a experiment, but I don't remember exactly where (some podcast), perhaps someone knows something about.

The experiment consisted in fooling an interviewer to think that he was going to interview someone while wearing a fake scar, to later report how he felt aversion from the persons being interviewed, how they stared differently because of the scar and so on. But actually, he'd do the interview without the fake scar, but wouldn't realize, and yet would believe that the persons actually stared differently at him, even pointing in the videotape of the interview when the person supposedly stared at him in a different manner.

Quite interesting, I think. Anyone knows about it? I don't remember anything besides this description. :(