I can relate with that question even in modern times. With the occasional stare I get from my superior during brain storming sessions. Like how could you possible get such insight being Black? Followed by refutations that defies logic.
It does have an awful effect on your morale, and in most cases one has to persistently prove one's competency to break down the walls of prejudice.
I wonder if other Software Engineers of African descent or other ethnic minorities in the West have similar experiences.
How do you scale through such hoops?
