From the liner notes of John H. McWhorter's Losing the Race: Self-Sabotage in Black America: "Is school a "white" thing? If not, then why do African-American students from comfortable middle-class backgrounds perform so badly in the classroom?" The theory is that blacks are held back in academic achievement by other blacks, who disdain excellence in schoolwork as "acting white".
This is an interesting phenomenon, but IMO it's not unique to blacks. Doing exceptionally well in school didn't score us white guys any social points either.
IMO it's not just academic performance that is inhibited by peers. You couldn't be too "arty" either, unless you had some offsetting virtue (probably athletics).