If you’ve traveled even a little bit, you’ve surely had the experience of sharing a public space with someone (or many someones) who wants to stand closer to you than you’d allow your partner most of the time. (I often had this experience at the ATMs in Baku, Azerbaijan, where crowding has replaced queuing.)
It’s because personal space — how close we stand to our colleagues, our friends, strangers — varies widely between countries. Sociologists have studied the whys and hows, and they’ve come up with some theories about why these social norms exist. Temperature tends to affect how people define personal space. So do gender and age.