In the experiment, white male basketball players watched one of three videos -- one depicting white players as the best free throwers in the NBA, one depicting black players as the best, and one that was completely neutral. The first was supposed to represent a positive stereotype to reinforce that apparently white men can jump after all.
Next, the players were asked to shoot some free throws, wherein half of them were videotaped and the other half were not. The results showed that the players who had been exposed to the positive stereotype performed better, but only if there wasn't any camera. So apparently, they only really believed in themselves as long as nobody was watching.
"OK, everyone turn around for a second."
So we guess the problem is, as interesting as the effect may be, working yourself up with positive stereotypes before the big game probably won't help you much unless you ask the entire audience to close their eyes the whole time.