Let’s say you are standing at a party, or in your office, or on your front lawn. Someone you vaguely know walks up to you. He walks up very close, face-to-face like the Seinfeld close-talker. Close enough that you can see up his nose and smell his breath. He starts a conversation. What do you do?

You will probably have a strong urge to step back. You may or may not do it, depending on the social situation and a host of other factors. But when someone we don’t know well enters our personal space bubble, it can be very uncomfortable.