Jazmyn Singleton, a black Duke senior agrees. After living in a predominantly white dorm freshman year, she lives with five African-American women in an all-black dormitory. “Both communities tend to be very judgmental,” says Ms. Singleton, ruefully. “There is pressure to be black. The black community can be harsh. People will say there are 600 blacks on campus but only two-thirds are ‘black’ because you can’t count blacks who hang out with white people.”