To see how this relates to decision making and the "search for excellence" check out a post from Greg Mankiw here. Surowiecki references a book by Nassim Taleb at the end of part III in chapter two. This paragraph explains in a nutshell the effect Derren Brown's system had on Khadisha in the clips above.
We seek out experts, because we get, as the writer Nassim Taleb asserts, "fooled by randomness". If there are enough people out there making predictions, a few of them are going to compile an impressive record over time. That does not mean that the record was the product of skill, nor does it mean that the record will continue into the future. Again, trying to find smart people will not lead you astray. Trying to find the smartest person will.