Dr. Fazio’s Indiana study found that three times as many randomly assigned interracial roommates were no longer living together at the end of the semester, compared with white roommates. The interracial roommates spent less time together, had fewer joint activities and were less involved with each other’s friends than the white pairs. And, the study found, whites’ pre-existing negative racial attitudes predicted which roommate arrangements would break up.

Several studies have shown that living with a roommate of a different race changes students’ attitudes. One, from the University of California at Los Angeles, generally found decreased prejudice among students with different-race roommates  but those who roomed with Asian-Americans, the group that scored the highest on measures of prejudice, became more prejudiced themselves.

Image Sam Boakye, an Ohio State University student, was determined to get good grades to prevent his white roommate from developing negative racial views. Credit... J. Kevin Fitzsimons for The New York Times

Professionals who watch over roommate relationships say that interracial roommate assignments are an important part of campus diversity.

“Most of them do fine, and I think it can be more interesting, because they have more to learn from each other,” said Phil Badaszewski, a hall director at Ohio State. “When there are conflicts, it’s usually different ideas about property sharing, or music, or cleanliness, or coming in late at night  the same things that can be problems for same-race roommates.”

Sometimes, such disputes mask underlying racial issues.

“I had one student who chose to move out, who said they just didn’t like the roommate’s friends, who were too loud,” Mr. Badaszewski said. “I thought there was a racial piece to it, but I didn’t bring it up and name it. It’s one of those topics  race, religion and politics  your parents tell you not to talk about at dinner because it can be explosive. And in this case, I knew it wouldn’t make things better.”

Occasionally, there are explicit racial problems.

“I had a black student who heard racist remarks being made in her quad,” said Gina Kozlowski, another Ohio State hall director. “She said she didn’t want it being made into a spectacle, and she didn’t want to be the person who had to educate her roommates about race.”