There's a curious and interesting social experiment that occurs every day on the train I take. It involves human nature and an acquired sense of entitlement that would seem to be inbred in us. Unless you get on the train at the first few stops, chances are good that you will have to share a row of seats with a stranger. There are two and three-seaters (with the middle one left open usually functioning as a sort of no-man's land demilitarized zone.) Each has its own set of psychological politics around it. What's striking is how quickly people gain a sense of ownership of their seats after sitting down in them. The vacant seats beside them are usually occupied by a bag or briefcase - and how willingly people make room for new arrivals is a fascinating character study. There are those who stare off into the distance acting like the people scanning the aisles for a seat just aren't there until they practically have to beg to be allowed to sit down like desperate asylum seekers. Others look up and smile quickly and vacate their belongings (These are almost invariably women in their middle years). In the three-seaters, a different dynamic takes place. The outside seat is empty so no permission is required to sit there. The middle baggage-occupying seat is another story. Many people, whose stuff takes up nearly the whole seat, make no effort to clear any space. Others make a token effort to shift their backpack a few inches - and this is appreciated. It's rare that someone will really clear a space for a new arrival like they are making a houseguest feel at home. I try to be this type of person. Once, when an especially prickly women got on next to me she thought I wasn't acting fast enough and nearly shrieked, "I just want half!" When I'm in a two-seater, though, I do admit that I secretly hope no one will sit next to me and usually only move my bag after someone has asked to sit down. Because somewhere deep inside I think that I (and all of us) secretly hope they won't have to cede any territory to strangers, no matter how tenuous our claims are. Which explains a lot.