The intriguing question prompted by Eibach's study is why whites and blacks are unconsciously drawn to different yardsticks. Eibach said one reason might be that racial equality means different things to whites and blacks: Whites see it as an ideal, blacks as a necessity. When people evaluate progress toward idealistic or optional goals -- saving for a vacation -- they tend to focus on progress made. But when people think of necessities -- paying the rent -- they focus on how much they are short.
That's a really important insight. White folks can wax lyrical about how we're getting closer to those ideals that animated the constitution and the American dream, because by and large they already possess them. It's other people for whom we're falling short. But for Blacks, those guarantees -- liberty, life, pursuit of happiness -- are not luxuries but necessities. And insofar as they do not have them, they're going to focus on what's missing, rather than the distance we've made from slavery to today.
The entire article is chock full of other good insights. I highly recommend that you read it in full.