Before you get too excited, keep in mind that this would also be true in a world in which racists are correct. That's still a world in which college graduates w

Before you get too excited, keep in mind that this would also be true in a world in which racists are correct. That's still a world in which college graduates would generally have college graduate roommates, people who wanted to live in hip neighborhoods would have roommates who wanted the same, and people who liked to get wasted and listen to loud music would live with folks who had the same tastes. It's easy to imagine this applying to age. If an 18-year-old and a 40-year-old share an apartment, it's probably because the 18-year-old is willing to be quiet after 10 PM, not smoke pot in the house, etc. Or because the 40-year-old is tolerant of late night noise and weed. However, the 18- or 40-year-old doesn't see it that way; to him, that 22-year age difference has surprisingly little impact on behavior. However, the this-is-compatible-with-racism viewpoint can be disproven by either a) assigning people random roommates (no, not random roommates who all got roughly the same SAT scores, want to live in the same state, etc.), or b) seeing if there's a selection process that affects whether people pick roommates of one ethnicity based on how closely they stereotypically match the behaviors of another.