We each have a dome of cautious space - an extension in part of our flesh - that gels and flexes depending on our surroundings. Any stranger that tiptoes into this space is treated as a kind of invader.
Thus concludes a Yale study, where the natural rhythms of bus passengers were logged over three years.
Passengers first priority was the maintenance of their dome - scowls, feigned sleep, and other trickery were used to keep people away from the empty seat next to them. But once the transport became too crowded, and a breach of the dome certain, people adapted and instead sought like a wiley bower-bird to entice a 'normal' person into their dome, and avoid any 'crazies'.
My point at the start - that our dome can expand or contract based on where we are, is based on the vague property rights we attach to our environment. Thus if, when wandering down the street, one bumps into a stranger, apologies are usually proffered by both parties, and rancour rarely follows. We recognise the silent dome of the other.
But if it were an s-series that cut in front of our sulking Citroen, then because of the implicit property rights attached to our car, and the fact that our dome has expanded to include it, we find this an unforgivable breach of our citadel, and our reaction follows a familiar course.
The padded seat on the bus is a greyer area, but the loose principle still applies, and our bodies are wider than they look.