<p>^^
Right. You are promised that your blocking mates will live in the same house, but that’s only 8 people (I think it’s 8 - maybe 12?). Then these blocks are thrown together with very varied blocks to create a relatively heterogeneous group (if you consider Harvard’s population to be heterogeneous to begin with). I don’t think this encourages “tribalism” at all. It guarantees that you will be living with a group of friends, and that there will be many such groups of different ilks living with you.</p>