While Stanley Milgram is best known for his experiments in convincing strangers to electrocute one another in the 1960s, he has also played a critical role in helping make sense of urban anonymity. In the early 1970s, through a series of surveys and experiments in public places such as train stations and university campuses, Milgram explored and refined the concept of the familiar stranger. If you have ever seen the same person repeatedly during your commute, in the gym, or in another public place, and have found yourself both curious about them and resistant to making eye contact, you will have an appreciation for the type of relationship Milgram sought to understand.
The concept is not well studied, but as cities grow and social networks evolve, the familiar stranger is increasingly of interest to everyone from transport planners to epidemiologists to dating coaches. It turns out that even people we have never spoken to and know nothing about can provide us with feelings of grounding and community, while our unacknowledged presence does the same for them.