One thing I have said many times,
The blacks that are direct from Africa are much different on a genetic level from the blacks descended from slaves.
This might sound a bit low, but slaves were selectively bred, much like dogs were. The ones that ended up strong and able to work the most were bred, and the ones that showed independence, and enough thought to potentially seek freedom were not.
I'm not saying that it's impossible to rise above genetics, but it is definitely disfavorable.
Call me a racist if you want, using dog analogies, but genetics DO play a roll in personality. For example, all (house) dogs are all the same species. Yet various breeds have distinct personalities, think about how chiwawas usually act, now think about a golden lab. They are of the same species, yet have very distinctive "racial" personalities.
Lets look at the attributes that were bred in, and those that were bred out.
breeding for Strength and stamina. Yes, it's a stereotype, but NFL football teams are disproportionately black.
breeding against traits that make them seek freedom and independence. Take a look at
http://www.topix.com/forum/afam/TS6CBT754MKNC4E90 , Blacks are disproportionately high on welfare.