It's a very very interesting study especially seeing how most people tend to identify themselves based upon perceived race and color.
People like to categorize. Animal, mineral, or vegetable, it's nice to have a good clean label. Same with race. And if we're not sure from the get-go, we even label kids of mixed race as whatever the child is closest to in features and skin tone (and, yes, I know the article states, basically, that we're all mixed anyway).
No matter how much evidence we see to the contrary, I'll always be black, Pariah will always be wrongy whitey, and Jack Mehoff will forever be green.